Sample records for accessory subunit kchip2

  1. Role of N-terminal domain and accessory subunits in controlling deactivation-inactivation coupling of Kv4.2 channels.

    PubMed

    Barghaan, Jan; Tozakidou, Magdalini; Ehmke, Heimo; Bähring, Robert

    2008-02-15

    We examined the relationship between deactivation and inactivation in Kv4.2 channels. In particular, we were interested in the role of a Kv4.2 N-terminal domain and accessory subunits in controlling macroscopic gating kinetics and asked if the effects of N-terminal deletion and accessory subunit coexpression conform to a kinetic coupling of deactivation and inactivation. We expressed Kv4.2 wild-type channels and N-terminal deletion mutants in the absence and presence of Kv channel interacting proteins (KChIPs) and dipeptidyl aminopeptidase-like proteins (DPPs) in human embryonic kidney 293 cells. Kv4.2-mediated A-type currents at positive and deactivation tail currents at negative membrane potentials were recorded under whole-cell voltage-clamp and analyzed by multi-exponential fitting. The observed changes in Kv4.2 macroscopic inactivation kinetics caused by N-terminal deletion, accessory subunit coexpression, or a combination of the two maneuvers were compared with respective changes in deactivation kinetics. Extensive correlation analyses indicated that modulatory effects on deactivation closely parallel respective effects on inactivation, including both onset and recovery kinetics. Searching for the structural determinants, which control deactivation and inactivation, we found that in a Kv4.2 Delta 2-10 N-terminal deletion mutant both the initial rapid phase of macroscopic inactivation and tail current deactivation were slowed. On the other hand, the intermediate and slow phase of A-type current decay, recovery from inactivation, and tail current decay kinetics were accelerated in Kv4.2 Delta 2-10 by KChIP2 and DPPX. Thus, a Kv4.2 N-terminal domain, which may control both inactivation and deactivation, is not necessary for active modulation of current kinetics by accessory subunits. Our results further suggest distinct mechanisms for Kv4.2 gating modulation by KChIPs and DPPs.

  2. Unanticipated region- and cell-specific downregulation of individual KChIP auxiliary subunit isotypes in Kv4.2 knock-out mouse brain.

    PubMed

    Menegola, Milena; Trimmer, James S

    2006-11-22

    Kv4 family voltage-gated potassium channel alpha subunits and Kv channel-interacting protein (KChIP) and dipeptidyl aminopeptidase-like protein subunits comprise somatodendritic A-type channels in mammalian neurons. Recently, a mouse was generated with a targeted deletion of Kv4.2, a Kv4 alpha subunit expressed in many but not all mammalian brain neurons. Kv4.2-/- mice are grossly indistinguishable from wild-type (WT) littermates. Here we used immunohistochemistry to analyze expression of component Kv4 and KChIP subunits of A-type channels in WT and Kv4.2-/- brains. We found that the expression level, and cellular and subcellular distribution of the other prominent brain Kv4 family member Kv4.3, was indistinguishable between WT and Kv4.2-/- samples. However, we found unanticipated regional and cell-specific decreases in expression of KChIPs. The degree of altered expression of individual KChIP isoforms in different regions and neurons precisely follows the level of Kv4.2 normally found at those sites and presumably their extent of association of these KChIPs with Kv4.2. The dramatic effects of Kv4.2 deletion on KChIP expression suggest that, in addition to previously characterized effects of KChIPs on the functional properties, trafficking, and turnover rate of Kv4 channels, Kv4:KChIP association may confer reciprocal Kv4.2-dependent effects on KChIPs. The impact of Kv4.2 deletion on KChIP expression also supports the major role of KChIPs as auxiliary subunits of Kv4 channels.

  3. The auxiliary subunit KChIP2 is an essential regulator of homeostatic excitability.

    PubMed

    Wang, Hong-Gang; He, Xiao Ping; Li, Qiang; Madison, Roger D; Moore, Scott D; McNamara, James O; Pitt, Geoffrey S

    2013-05-10

    The necessity for, or redundancy of, distinctive KChIP proteins is not known. Deletion of KChIP2 leads to increased susceptibility to epilepsy and to a reduction in IA and increased excitability in pyramidal hippocampal neurons. KChIP2 is essential for homeostasis in hippocampal neurons. Mutations in K(A) channel auxiliary subunits may be loci for epilepsy. The somatodendritic IA (A-type) K(+) current underlies neuronal excitability, and loss of IA has been associated with the development of epilepsy. Whether any one of the four auxiliary potassium channel interacting proteins (KChIPs), KChIP1-KChIP4, in specific neuronal populations is critical for IA is not known. Here we show that KChIP2, which is abundantly expressed in hippocampal pyramidal cells, is essential for IA regulation in hippocampal neurons and that deletion of Kchip2 affects susceptibility to limbic seizures. The specific effects of Kchip2 deletion on IA recorded from isolated hippocampal pyramidal neurons were a reduction in amplitude and shift in the V½ for steady-state inactivation to hyperpolarized potentials when compared with WT neurons. Consistent with the relative loss of IA, hippocampal neurons from Kchip2(-/-) mice showed increased excitability. WT cultured neurons fired only occasional single action potentials, but the average spontaneous firing rate (spikes/s) was almost 10-fold greater in Kchip2(-/-) neurons. In slice preparations, spontaneous firing was detected in CA1 pyramidal neurons from Kchip2(-/-) mice but not from WT. Additionally, when seizures were induced by kindling, the number of stimulations required to evoke an initial class 4 or 5 seizure was decreased, and the average duration of electrographic seizures was longer in Kchip2(-/-) mice compared with WT controls. Together, these data demonstrate that the KChIP2 is essential for physiologic IA modulation and homeostatic stability and that there is a lack of functional redundancy among the different KChIPs in hippocampal

  4. Different KChIPs compete for heteromultimeric assembly with pore-forming Kv4 subunits.

    PubMed

    Zhou, Jingheng; Tang, Yiquan; Zheng, Qin; Li, Meng; Yuan, Tianyi; Chen, Liangyi; Huang, Zhuo; Wang, KeWei

    2015-06-02

    Auxiliary Kv channel-interacting proteins 1-4 (KChIPs1-4) coassemble with pore-forming Kv4 α-subunits to form channel complexes underlying somatodendritic subthreshold A-type current that regulates neuronal excitability. It has been hypothesized that different KChIPs can competitively bind to Kv4 α-subunit to form variable channel complexes that can exhibit distinct biophysical properties for modulation of neural function. In this study, we use single-molecule subunit counting by total internal reflection fluorescence microscopy in combinations with electrophysiology and biochemistry to investigate whether different isoforms of auxiliary KChIPs, KChIP4a, and KChIP4bl, can compete for binding of Kv4.3 to coassemble heteromultimeric channel complexes for modulation of channel function. To count the number of photobleaching steps solely from cell membrane, we take advantage of a membrane tethered k-ras-CAAX peptide that anchors cytosolic KChIP4 proteins to the surface for reduction of background noise. Single-molecule subunit counting reveals that the number of KChIP4 isoforms in Kv4.3-KChIP4 complexes can vary depending on the KChIP4 expression level. Increasing the amount of KChIP4bl gradually reduces bleaching steps of KChIP4a isoform proteins, and vice versa. Further analysis of channel gating kinetics from different Kv4-KChIP4 subunit compositions confirms that both KChIP4a and KChIP4bl can modulate the channel complex function upon coassembly. Taken together, our findings show that auxiliary KChIPs can heteroassemble with Kv4 in a competitive manner to form heteromultimeric Kv4-KChIP4 channel complexes that are biophysically distinct and regulated under physiological or pathological conditions. Copyright © 2015 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  5. KChIPs and Kv4 alpha subunits as integral components of A-type potassium channels in mammalian brain.

    PubMed

    Rhodes, Kenneth J; Carroll, Karen I; Sung, M Amy; Doliveira, Lisa C; Monaghan, Michael M; Burke, Sharon L; Strassle, Brian W; Buchwalder, Lynn; Menegola, Milena; Cao, Jie; An, W Frank; Trimmer, James S

    2004-09-08

    Voltage-gated potassium (Kv) channels from the Kv4, or Shal-related, gene family underlie a major component of the A-type potassium current in mammalian central neurons. We recently identified a family of calcium-binding proteins, termed KChIPs (Kv channel interacting proteins), that bind to the cytoplasmic N termini of Kv4 family alpha subunits and modulate their surface density, inactivation kinetics, and rate of recovery from inactivation (An et al., 2000). Here, we used single and double-label immunohistochemistry, together with circumscribed lesions and coimmunoprecipitation analyses, to examine the regional and subcellular distribution of KChIPs1-4 and Kv4 family alpha subunits in adult rat brain. Immunohistochemical staining using KChIP-specific monoclonal antibodies revealed that the KChIP polypeptides are concentrated in neuronal somata and dendrites where their cellular and subcellular distribution overlaps, in an isoform-specific manner, with that of Kv4.2 and Kv4.3. For example, immunoreactivity for KChIP1 and Kv4.3 is concentrated in the somata and dendrites of hippocampal, striatal, and neocortical interneurons. Immunoreactivity for KChIP2, KChIP4, and Kv4.2 is concentrated in the apical and basal dendrites of hippocampal and neocortical pyramidal cells. Double-label immunofluorescence labeling revealed that throughout the forebrain, KChIP2 and KChIP4 are frequently colocalized with Kv4.2, whereas in cortical, hippocampal, and striatal interneurons, KChIP1 is frequently colocalized with Kv4.3. Coimmunoprecipitation analyses confirmed that all KChIPs coassociate with Kv4 alpha subunits in brain membranes, indicating that KChIPs 1-4 are integral components of native A-type Kv channel complexes and are likely to play a major role as modulators of somatodendritic excitability.

  6. Somatodendritic surface expression of epitope-tagged and KChIP binding-deficient Kv4.2 channels in hippocampal neurons.

    PubMed

    Prechtel, Helena; Hartmann, Sven; Minge, Daniel; Bähring, Robert

    2018-01-01

    Kv4.2 channels mediate a subthreshold-activating somatodendritic A-type current (ISA) in hippocampal neurons. We examined the role of accessory Kv channel interacting protein (KChIP) binding in somatodendritic surface expression and activity-dependent decrease in the availability of Kv4.2 channels. For this purpose we transfected cultured hippocampal neurons with cDNA coding for Kv4.2 wild-type (wt) or KChIP binding-deficient Kv4.2 mutants. All channels were equipped with an externally accessible hemagglutinin (HA)-tag and an EGFP-tag, which was attached to the C-terminal end. Combined analyses of EGFP self-fluorescence, surface HA immunostaining and patch-clamp recordings demonstrated similar dendritic trafficking and functional surface expression for Kv4.2[wt]HA,EGFP and the KChIP binding-deficient Kv4.2[A14K]HA,EGFP. Coexpression of exogenous KChIP2 augmented the surface expression of Kv4.2[wt]HA,EGFP but not Kv4.2[A14K]HA,EGFP. Notably, activity-dependent decrease in availability was more pronounced in Kv4.2[wt]HA,EGFP + KChIP2 coexpressing than in Kv4.2[A14K]HA,EGFP + KChIP2 coexpressing neurons. Our results do not support the notion that accessory KChIP binding is a prerequisite for dendritic trafficking and functional surface expression of Kv4.2 channels, however, accessory KChIP binding may play a potential role in Kv4.2 modulation during intrinsic plasticity processes.

  7. KChIP1 modulation of Kv4.3-mediated A-type K(+) currents and repetitive firing in hippocampal interneurons.

    PubMed

    Bourdeau, M L; Laplante, I; Laurent, C E; Lacaille, J-C

    2011-03-10

    Neuronal A-type K(+) channels regulate action potential waveform, back-propagation and firing frequency. In hippocampal CA1 interneurons located at the stratum lacunosum-moleculare/radiatum junction (LM/RAD), Kv4.3 mediates A-type K(+) currents and a Kv4 β-subunit of the Kv channel interacting protein (KChIP) family, KChIP1, appears specifically expressed in these cells. However, the functional role of this accessory subunit in A-type K(+) currents and interneuron excitability remains largely unknown. Thus, first we studied KChIP1 and Kv4.3 channel interactions in human embryonic kidney 293 (HEK293) cells and determined that KChIP1 coexpression modulated the biophysical properties of Kv4.3 A-type currents (faster recovery from inactivation, leftward shift of activation curve, faster rise time and slower decay) and this modulation was selectively prevented by KChIP1 short interfering RNA (siRNA) knockdown. Next, we evaluated the effects of KChIP1 down-regulation by siRNA on A-type K(+) currents in LM/RAD interneurons in slice cultures. Recovery from inactivation of A-type K(+) currents was slower after KChIP1 down-regulation but other properties were unchanged. In addition, down-regulation of KChIP1 levels did not affect action potential waveform and firing, but increased firing frequency during suprathreshold depolarizations, indicating that KChIP1 regulates interneuron excitability. The effects of KChIP1 down-regulation were cell-specific since CA1 pyramidal cells that do not express KChIP1 were unaffected. Overall, our findings suggest that KChIP1 interacts with Kv4.3 in LM/RAD interneurons, enabling faster recovery from inactivation of A-type currents and thus promoting stronger inhibitory control of firing during sustained activity. Copyright © 2011 IBRO. Published by Elsevier Ltd. All rights reserved.

  8. Multiprotein assembly of Kv4.2, KChIP3 and DPP10 produces ternary channel complexes with ISA-like properties.

    PubMed

    Jerng, Henry H; Kunjilwar, Kumud; Pfaffinger, Paul J

    2005-11-01

    Kv4 pore-forming subunits are the principal constituents of the voltage-gated K+ channel underlying somatodendritic subthreshold A-type currents (I(SA)) in neurones. Two structurally distinct types of Kv4 channel modulators, Kv channel-interacting proteins (KChIPs) and dipeptidyl-peptidase-like proteins (DPLs: DPP6 or DPPX, DPP10 or DPPY), enhance surface expression and modify functional properties. Since KChIP and DPL distributions overlap in the brain, we investigated the potential coassembly of Kv4.2, KChIP3 and DPL proteins, and the contribution of DPLs to ternary complex properties. Immunoprecipitation results show that KChIP3 and DPP10 associate simultaneously with Kv4.2 proteins in rat brain as well as heterologously expressing Xenopus oocytes, indicating Kv4.2 + KChIP3 + DPP10 multiprotein complexes. Consistent with ternary complex formation, coexpression of Kv4.2, KChIP3 and DPP10 in oocytes and CHO cells results in current waveforms distinct from the arithmetic sum of Kv4.2 + KChIP3 and Kv4.2 + DPP10 currents. Furthermore, the Kv4.2 + KChIP3 + DPP10 channels recover from inactivation very rapidly (tau(rec) approximately 18-26 ms), closely matching that of native I(SA) and significantly faster than the recovery of Kv4.2 + KChIP3 or Kv4.2 + DPP10 channels. For comparison, identical triple coexpression experiments were performed using DPP6 variants. While most results are similar, the Kv4.2 + KChIP3 + DPP6 channels exhibit inactivation that slows with increasing membrane potential, resulting in inactivation slower than that of Kv4.2 + KChIP3 + DPP10 channels at positive voltages. In conclusion, the native neuronal subthreshold A-type channel is probably a macromolecular complex formed from Kv4 and a combination of both KChIP and DPL proteins, with the precise composition of channel alpha and auxiliary subunits underlying tissue and regional variability in I(SA) properties.

  9. [Modulation of Kv4 channels by KChIPs clamping].

    PubMed

    Cui, Yuan-Yuan; Wang, Ke-Wei

    2009-01-01

    The rapidly inactivating (A-type) potassium channels regulate membrane excitability that defines the fundamental mechanism of neuronal functions such as pain signaling. Cytosolic Kv channel-interacting proteins KChIPs co-assemble with Kv4 (Shal) alpha subunits to form a native complex. The specific binding of auxiliary KChIPs to the Kv4 N-terminus results in modulation of gating properties, surface expression and subunit assembly of Kv4 channels. Based on recent structural efforts, here we attempt to emphasize the interaction between KChIPs and Kv4 channel complex in which a single KChIP1 molecule laterally clamps two neighboring Kv4.3 N-termini in a 4:4 manner. Greater insights into molecular mechanism between KChIPs and Kv4 interaction may provide therapeutic potentials by structure-based design of chemical compounds aimed at disrupting the protein-protein interaction for treatment of membrane excitability-related disorders.

  10. Modulation by clamping: Kv4 and KChIP interactions.

    PubMed

    Wang, Kewei

    2008-10-01

    The rapidly inactivating (A-type) potassium channels regulate membrane excitability that defines the fundamental mechanism of neuronal functions such as pain signaling. Cytosolic Kv channel-interacting proteins KChIPs that belong to neuronal calcium sensor (NCS) family of calcium binding EF-hand proteins co-assemble with Kv4 (Shal) alpha subunits to form a native complex that encodes major components of neuronal somatodendritic A-type K+ current, I(SA), in neurons and transient outward current, I(TO), in cardiac myocytes. The specific binding of auxiliary KChIPs to the Kv4 N-terminus results in modulation of gating properties, surface expression and subunit assembly of Kv4 channels. Here, I attempt to emphasize the interaction between KChIPs and Kv4 based on recent progress made in understanding the structure complex in which a single KChIP1 molecule laterally clamps two neighboring Kv4.3 N-termini in a 4:4 manner. Greater insights into molecular mechanism between KChIPs and Kv4 interaction may provide therapeutic potentials of designing compounds aimed at disrupting the protein-protein interaction for treatment of membrane excitability-related disorders.

  11. NHE isoform switching and KChIP2 upregulation in aging porcine atria.

    PubMed

    Kant, Ritu; Hu, Zhaoyang; Malhotra, Jaideep K; Krogh-Madsen, Trine; Christini, David J; Heerdt, Paul M; Abbott, Geoffrey W

    2013-01-01

    Aging increases the risk of cardiac pathologies including atrial fibrillation and can alter myocardial responsiveness to therapeutic agents. Here, seeking molecular correlates of myocardial aging processes, we performed global "whole transcript" analysis of 25,388 genes using 572,667 probes to compare the left atrial (LA) transcriptomes of young adult (9 months old) versus elderly (10 years old) female swine. NHE2 (>9-fold) and KChIP2 (3.8-fold) exhibited the highest aging-related expression increases. Real-time qPCR recapitulated these findings and indicated a 50% decrease in LA NHE1, a twofold increase in right atrial KChIP2, but no significant changes for these transcripts in either ventricle. Notably, even in young adult pigs, NHE2 transcript was detectable and enriched in the atria over the ventricles. NHE1, the recognized cardiac isoform of the sodium hydrogen exchanger, has proven a compelling but clinically disappointing therapeutic target with respect to reperfusion arrhythmias. Our data challenge the dogma that NHE1 is alone in the myocardium and suggest that NHE2 could negatively impact the pharmacological responsiveness of atrial tissue to NHE1-specific inhibitors. KChIP2 is a cytosolic β subunit essential for generation of I to. The increased KChIP2 expression we observed with aging substantially shortened in silico atrial myocyte action potential duration, a predisposing factor in atrial fibrillation. Consistent with this, 4/5 elderly swine sustained pacing-induced AF≥15 s after cessation of stimulation, compared to 0/3 young swine. Our findings uncover potential molecular bases for increased arrhythmogenicity and reduced pharmacologic efficacy in the aging atrium, in a large animal model of human cardiac physiology.

  12. Potassium Channel Interacting Protein 2 (KChIP2) is not a transcriptional regulator of cardiac electrical remodeling

    PubMed Central

    Winther, Sine V.; Tuomainen, Tomi; Borup, Rehannah; Tavi, Pasi; Antoons, Gudrun; Thomsen, Morten B.

    2016-01-01

    The heart-failure relevant Potassium Channel Interacting Protein 2 (KChIP2) augments CaV1.2 and KV4.3. KChIP3 represses CaV1.2 transcription in cardiomyocytes via interaction with regulatory DNA elements. Hence, we tested nuclear presence of KChIP2 and if KChIP2 translocates into the nucleus in a Ca2+ dependent manner. Cardiac biopsies from human heart-failure patients and healthy donor controls showed that nuclear KChIP2 abundance was significantly increased in heart failure; however, this was secondary to a large variation of total KChIP2 content. Administration of ouabain did not increase KChIP2 content in nuclear protein fractions in anesthetized mice. KChIP2 was expressed in cell lines, and Ca2+ ionophores were applied in a concentration- and time-dependent manner. The cell lines had KChIP2-immunoreactive protein in the nucleus in the absence of treatments to modulate intracellular Ca2+ concentration. Neither increasing nor decreasing intracellular Ca2+ concentrations caused translocation of KChIP2. Microarray analysis did not identify relief of transcriptional repression in murine KChIP2−/− heart samples. We conclude that although there is a baseline presence of KChIP2 in the nucleus both in vivo and in vitro, KChIP2 does not directly regulate transcriptional activity. Moreover, the nuclear transport of KChIP2 is not dependent on Ca2+. Thus, KChIP2 does not function as a conventional transcription factor in the heart. PMID:27349185

  13. KChIP2 genotype dependence of transient outward current (Ito) properties in cardiomyocytes isolated from male and female mice

    PubMed Central

    Waldschmidt, Lara; Junkereit, Vera; Bähring, Robert

    2017-01-01

    The transient outward current (Ito) in cardiomyocytes is largely mediated by Kv4 channels associated with Kv Channel Interacting Protein 2 (KChIP2). A knockout model has documented the critical role of KChIP2 in Ito expression. The present study was conducted to characterize in both sexes the dependence of Ito properties, including current magnitude, inactivation kinetics, recovery from inactivation and voltage dependence of inactivation, on the number of functional KChIP2 alleles. For this purpose we performed whole-cell patch-clamp experiments on isolated left ventricular cardiomyocytes from male and female mice which had different KChIP2 genotypes; i.e., wild-type (KChIP2+/+), heterozygous knockout (KChIP2+/-) or complete knockout of KChIP2 (KChIP2-/-). We found in both sexes a KChIP2 gene dosage effect (i.e., a proportionality between number of alleles and phenotype) on Ito magnitude, however, concerning other Ito properties, KChIP2+/- resembled KChIP2+/+. Only in the total absence of KChIP2 (KChIP2-/-) we observed a slowing of Ito kinetics, a slowing of recovery from inactivation and a negative shift of a portion of the voltage dependence of inactivation. In a minor fraction of KChIP2-/- myocytes Ito was completely lost. The distinct KChIP2 genotype dependences of Ito magnitude and inactivation kinetics, respectively, seen in cardiomyocytes were reproduced with two-electrode voltage-clamp experiments on Xenopus oocytes expressing Kv4.2 and different amounts of KChIP2. Our results corroborate the critical role of KChIP2 in controlling Ito properties. They demonstrate that the Kv4.2/KChIP2 interaction in cardiomyocytes is highly dynamic, with a clear KChIP2 gene dosage effect on Kv4 channel surface expression but not on inactivation gating. PMID:28141821

  14. KChIP2 genotype dependence of transient outward current (Ito) properties in cardiomyocytes isolated from male and female mice.

    PubMed

    Waldschmidt, Lara; Junkereit, Vera; Bähring, Robert

    2017-01-01

    The transient outward current (Ito) in cardiomyocytes is largely mediated by Kv4 channels associated with Kv Channel Interacting Protein 2 (KChIP2). A knockout model has documented the critical role of KChIP2 in Ito expression. The present study was conducted to characterize in both sexes the dependence of Ito properties, including current magnitude, inactivation kinetics, recovery from inactivation and voltage dependence of inactivation, on the number of functional KChIP2 alleles. For this purpose we performed whole-cell patch-clamp experiments on isolated left ventricular cardiomyocytes from male and female mice which had different KChIP2 genotypes; i.e., wild-type (KChIP2+/+), heterozygous knockout (KChIP2+/-) or complete knockout of KChIP2 (KChIP2-/-). We found in both sexes a KChIP2 gene dosage effect (i.e., a proportionality between number of alleles and phenotype) on Ito magnitude, however, concerning other Ito properties, KChIP2+/- resembled KChIP2+/+. Only in the total absence of KChIP2 (KChIP2-/-) we observed a slowing of Ito kinetics, a slowing of recovery from inactivation and a negative shift of a portion of the voltage dependence of inactivation. In a minor fraction of KChIP2-/- myocytes Ito was completely lost. The distinct KChIP2 genotype dependences of Ito magnitude and inactivation kinetics, respectively, seen in cardiomyocytes were reproduced with two-electrode voltage-clamp experiments on Xenopus oocytes expressing Kv4.2 and different amounts of KChIP2. Our results corroborate the critical role of KChIP2 in controlling Ito properties. They demonstrate that the Kv4.2/KChIP2 interaction in cardiomyocytes is highly dynamic, with a clear KChIP2 gene dosage effect on Kv4 channel surface expression but not on inactivation gating.

  15. Unorthodox Acetylcholine Binding Sites Formed by α5 and β3 Accessory Subunits in α4β2* Nicotinic Acetylcholine Receptors.

    PubMed

    Jain, Akansha; Kuryatov, Alexander; Wang, Jingyi; Kamenecka, Theodore M; Lindstrom, Jon

    2016-11-04

    All nicotinic acetylcholine receptors (nAChRs) evolved from homomeric nAChRs in which all five subunits are involved in forming acetylcholine (ACh) binding sites at their interfaces. Heteromeric α4β2* nAChRs typically have two ACh binding sites at α4/β2 interfaces and a fifth accessory subunit surrounding the central cation channel. β2 accessory subunits do not form ACh binding sites, but α4 accessory subunits do at the α4/α4 interface in (α4β2) 2 α4 nAChRs. α5 and β3 are closely related subunits that had been thought to act only as accessory subunits and not take part in forming ACh binding sites. The effect of agonists at various subunit interfaces was determined by blocking homologous sites at these interfaces using the thioreactive agent 2-((trimethylammonium)ethyl) methanethiosulfonate (MTSET). We found that α5/α4 and β3/α4 interfaces formed ACh binding sites in (α4β2) 2 α5 and (α4β2) 2 β3 nAChRs. The α4/α5 interface in (β2α4) 2 α5 nAChRs also formed an ACh binding site. Blocking of these sites with MTSET reduced the maximal ACh evoked responses of these nAChRs by 30-50%. However, site-selective agonists NS9283 (for the α4/α4 site) and sazetidine-A (for the α4/β2 site) did not act on the ACh sites formed by the α5/α4 or β3/α4 interfaces. This suggests that unorthodox sites formed by α5 and β3 subunits have unique ligand selectivity. Agonists or antagonists for these unorthodox sites might be selective and effective drugs for modulating nAChR function to treat nicotine addiction and other disorders. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  16. Expression and distribution of Kv4 potassium channel subunits and potassium channel interacting proteins in subpopulations of interneurons in the basolateral amygdala.

    PubMed

    Dabrowska, J; Rainnie, D G

    2010-12-15

    The Kv4 potassium channel α subunits, Kv4.1, Kv4.2, and Kv4.3, determine some of the fundamental physiological properties of neurons in the CNS. Kv4 subunits are associated with auxiliary β-subunits, such as the potassium channel interacting proteins (KChIP1 - 4), which are thought to regulate the trafficking and gating of native Kv4 potassium channels. Intriguingly, KChIP1 is thought to show cell type-selective expression in GABA-ergic inhibitory interneurons, while other β-subunits (KChIP2-4) are associated with principal glutamatergic neurons. However, nothing is known about the expression of Kv4 family α- and β-subunits in specific interneurons populations in the BLA. Here, we have used immunofluorescence, co-immunoprecipitation, and Western Blotting to determine the relative expression of KChIP1 in the different interneuron subtypes within the BLA, and its co-localization with one or more of the Kv4 α subunits. We show that all three α-subunits of Kv4 potassium channel are found in rat BLA neurons, and that the immunoreactivity of KChIP1 closely resembles that of Kv4.3. Indeed, Kv4.3 showed almost complete co-localization with KChIP1 in the soma and dendrites of a distinct subpopulation of BLA neurons. Dual-immunofluorescence studies revealed this to be in BLA interneurons immunoreactive for parvalbumin, cholecystokin-8, and somatostatin. Finally, co-immunoprecipitation studies showed that KChIP1 was associated with all three Kv4 α subunits. Together our results suggest that KChIP1 is selectively expressed in BLA interneurons where it may function to regulate the activity of A-type potassium channels. Hence, KChIP1 might be considered as a cell type-specific regulator of GABAergic inhibitory circuits in the BLA. Copyright © 2010 IBRO. Published by Elsevier Ltd. All rights reserved.

  17. Modulatory mechanisms and multiple functions of somatodendritic A-type K (+) channel auxiliary subunits.

    PubMed

    Jerng, Henry H; Pfaffinger, Paul J

    2014-01-01

    Auxiliary subunits are non-conducting, modulatory components of the multi-protein ion channel complexes that underlie normal neuronal signaling. They interact with the pore-forming α-subunits to modulate surface distribution, ion conductance, and channel gating properties. For the somatodendritic subthreshold A-type potassium (ISA) channel based on Kv4 α-subunits, two types of auxiliary subunits have been extensively studied: Kv channel-interacting proteins (KChIPs) and dipeptidyl peptidase-like proteins (DPLPs). KChIPs are cytoplasmic calcium-binding proteins that interact with intracellular portions of the Kv4 subunits, whereas DPLPs are type II transmembrane proteins that associate with the Kv4 channel core. Both KChIPs and DPLPs genes contain multiple start sites that are used by various neuronal populations to drive the differential expression of functionally distinct N-terminal variants. In turn, these N-terminal variants generate tremendous functional diversity across the nervous system. Here, we focus our review on (1) the molecular mechanism underlying the unique properties of different N-terminal variants, (2) the shaping of native ISA properties by the concerted actions of KChIPs and DPLP variants, and (3) the surprising ways that KChIPs and DPLPs coordinate the activity of multiple channels to fine-tune neuronal excitability. Unlocking the unique contributions of different auxiliary subunit N-terminal variants may provide an important opportunity to develop novel targeted therapeutics to treat numerous neurological disorders.

  18. Modulatory mechanisms and multiple functions of somatodendritic A-type K+ channel auxiliary subunits

    PubMed Central

    Jerng, Henry H.; Pfaffinger, Paul J.

    2014-01-01

    Auxiliary subunits are non-conducting, modulatory components of the multi-protein ion channel complexes that underlie normal neuronal signaling. They interact with the pore-forming α-subunits to modulate surface distribution, ion conductance, and channel gating properties. For the somatodendritic subthreshold A-type potassium (ISA) channel based on Kv4 α-subunits, two types of auxiliary subunits have been extensively studied: Kv channel-interacting proteins (KChIPs) and dipeptidyl peptidase-like proteins (DPLPs). KChIPs are cytoplasmic calcium-binding proteins that interact with intracellular portions of the Kv4 subunits, whereas DPLPs are type II transmembrane proteins that associate with the Kv4 channel core. Both KChIPs and DPLPs genes contain multiple start sites that are used by various neuronal populations to drive the differential expression of functionally distinct N-terminal variants. In turn, these N-terminal variants generate tremendous functional diversity across the nervous system. Here, we focus our review on (1) the molecular mechanism underlying the unique properties of different N-terminal variants, (2) the shaping of native ISA properties by the concerted actions of KChIPs and DPLP variants, and (3) the surprising ways that KChIPs and DPLPs coordinate the activity of multiple channels to fine-tune neuronal excitability. Unlocking the unique contributions of different auxiliary subunit N-terminal variants may provide an important opportunity to develop novel targeted therapeutics to treat numerous neurological disorders. PMID:24723849

  19. Preservation of cardiac function by prolonged action potentials in mice deficient of KChIP2.

    PubMed

    Grubb, Søren; Aistrup, Gary L; Koivumäki, Jussi T; Speerschneider, Tobias; Gottlieb, Lisa A; Mutsaers, Nancy A M; Olesen, Søren-Peter; Calloe, Kirstine; Thomsen, Morten B

    2015-08-01

    Inherited ion channelopathies and electrical remodeling in heart disease alter the cardiac action potential with important consequences for excitation-contraction coupling. Potassium channel-interacting protein 2 (KChIP2) is reduced in heart failure and interacts under physiological conditions with both Kv4 to conduct the fast-recovering transient outward K(+) current (Ito,f) and with CaV1.2 to mediate the inward L-type Ca(2+) current (ICa,L). Anesthetized KChIP2(-/-) mice have normal cardiac contraction despite the lower ICa,L, and we hypothesized that the delayed repolarization could contribute to the preservation of contractile function. Detailed analysis of current kinetics shows that only ICa,L density is reduced, and immunoblots demonstrate unaltered CaV1.2 and CaVβ₂ protein levels. Computer modeling suggests that delayed repolarization would prolong the period of Ca(2+) entry into the cell, thereby augmenting Ca(2+)-induced Ca(2+) release. Ca(2+) transients in disaggregated KChIP2(-/-) cardiomyocytes are indeed comparable to wild-type transients, corroborating the preserved contractile function and suggesting that the compensatory mechanism lies in the Ca(2+)-induced Ca(2+) release event. We next functionally probed dyad structure, ryanodine receptor Ca(2+) sensitivity, and sarcoplasmic reticulum Ca(2+) load and found that increased temporal synchronicity of the Ca(2+) release in KChIP2(-/-) cardiomyocytes may reflect improved dyad structure aiding the compensatory mechanisms in preserving cardiac contractile force. Thus the bimodal effect of KChIP2 on Ito,f and ICa,L constitutes an important regulatory effect of KChIP2 on cardiac contractility, and we conclude that delayed repolarization and improved dyad structure function together to preserve cardiac contraction in KChIP2(-/-) mice. Copyright © 2015 the American Physiological Society.

  20. Spatial distributions of Kv4 channels and KChip2 isoforms in the murine heart based on laser capture microdissection.

    PubMed

    Teutsch, Christine; Kondo, Richard P; Dederko, Dorothy A; Chrast, Jacqueline; Chien, Kenneth R; Giles, Wayne R

    2007-03-01

    Regional differences in repolarizing K(+) current densities and expression levels of their molecular components are important for coordinating the pattern of electrical excitation and repolarization of the heart. The small size of hearts from mice may obscure these interventricular and/or transmural expression differences of K(+) channels. We have examined this possibility in adult mouse ventricle using a technology that provides very high spatial resolution of tissue collection. Conventional manual dissection and laser capture microdissection (LCM) were utilized to dissect tissue from distinct ventricular regions. RNA was isolated from epicardial, mid-myocardial and endocardial layers of both the right and left ventricles. Real-time RT-PCR was used to quantify the transcript expression in these different regions. LCM revealed significant interventricular and transmural gradients for both Kv4.2 and the alpha-subunit of KChIP2. The expression profile of a second K(+) channel transcript, Kir2.1, which is responsible for the inwardly rectifying K(+) current I(k1), showed no interventricular or transmural gradients and therefore served as a negative control. Our findings are in contrast to previous reports of a relatively uniform left ventricular transmural pattern of expression of Kv4.2, Kv4.3 and KChIP2 in adult mouse heart, which appear to be different than that in larger mammals. Specifically, our results demonstrate significant epi- to endocardial differences in the patterns of expression of both Kv4.2 and KChIP2.

  1. β Subunits Functionally Differentiate Human Kv4.3 Potassium Channel Splice Variants

    PubMed Central

    Abbott, Geoffrey W.

    2017-01-01

    The human ventricular cardiomyocyte transient outward K+ current (Ito) mediates the initial phase of myocyte repolarization and its disruption is implicated in Brugada Syndrome and heart failure (HF). Human cardiac Ito is generated primarily by two Kv4.3 splice variants (Kv4.3L and Kv4.3S, diverging only by a C-terminal, S6-proximal, 19-residue stretch unique to Kv4.3L), which are differentially remodeled in HF, but considered functionally alike at baseline. Kv4.3 is regulated in human heart by β subunits including KChIP2b and KCNEs, but their effects were previously assumed to be Kv4.3 isoform-independent. Here, this assumption was tested experimentally using two-electrode voltage-clamp analysis of human subunits co-expressed in Xenopus laevis oocytes. Unexpectedly, Kv4.3L-KChIP2b channels exhibited up to 8-fold lower current augmentation, 40% slower inactivation, and 5 mV-shifted steady-state inactivation compared to Kv4.3S-KChIP2b. A synthetic peptide mimicking the 19-residue stretch diminished these differences, reinforcing the importance of this segment in mediating Kv4.3 regulation by KChIP2b. KCNE subunits induced further functional divergence, including a 7-fold increase in Kv4.3S-KCNE4-KChIP2b current compared to Kv4.3L-KCNE4-KChIP2b. The discovery of β-subunit-dependent functional divergence in human Kv4.3 splice variants suggests a C-terminal signaling hub is crucial to governing β-subunit effects upon Kv4.3, and demonstrates the potential significance of differential Kv4.3 gene-splicing and β subunit expression in myocyte physiology and pathobiology. PMID:28228734

  2. β Subunits Functionally Differentiate Human Kv4.3 Potassium Channel Splice Variants.

    PubMed

    Abbott, Geoffrey W

    2017-01-01

    The human ventricular cardiomyocyte transient outward K + current ( I to ) mediates the initial phase of myocyte repolarization and its disruption is implicated in Brugada Syndrome and heart failure (HF). Human cardiac I to is generated primarily by two Kv4.3 splice variants (Kv4.3L and Kv4.3S, diverging only by a C-terminal, S6-proximal, 19-residue stretch unique to Kv4.3L), which are differentially remodeled in HF, but considered functionally alike at baseline. Kv4.3 is regulated in human heart by β subunits including KChIP2b and KCNEs, but their effects were previously assumed to be Kv4.3 isoform-independent. Here, this assumption was tested experimentally using two-electrode voltage-clamp analysis of human subunits co-expressed in Xenopus laevis oocytes. Unexpectedly, Kv4.3L-KChIP2b channels exhibited up to 8-fold lower current augmentation, 40% slower inactivation, and 5 mV-shifted steady-state inactivation compared to Kv4.3S-KChIP2b. A synthetic peptide mimicking the 19-residue stretch diminished these differences, reinforcing the importance of this segment in mediating Kv4.3 regulation by KChIP2b. KCNE subunits induced further functional divergence, including a 7-fold increase in Kv4.3S-KCNE4-KChIP2b current compared to Kv4.3L-KCNE4-KChIP2b. The discovery of β-subunit-dependent functional divergence in human Kv4.3 splice variants suggests a C-terminal signaling hub is crucial to governing β-subunit effects upon Kv4.3, and demonstrates the potential significance of differential Kv4.3 gene-splicing and β subunit expression in myocyte physiology and pathobiology.

  3. Small things considered: the small accessory subunits of RNA polymerase in Gram-positive bacteria

    PubMed Central

    Weiss, Andy; Shaw, Lindsey N.

    2015-01-01

    The DNA-dependent RNA polymerase core enzyme in Gram-positive bacteria consists of seven subunits. Whilst four of them (α2ββ′) are essential, three smaller subunits, δ, ε and ω (∼9–21.5 kDa), are considered accessory. Both δ and ω have been viewed as integral components of RNAP for several decades; however, ε has only recently been described. Functionally these three small subunits carry out a variety of tasks, imparting important, supportive effects on the transcriptional process of Gram-positive bacteria. While ω is thought to have a wide range of roles, reaching from maintaining structural integrity of RNAP to σ factor recruitment, the only suggested function for ε thus far is in protecting cells from phage infection. The third subunit, δ, has been shown to have distinct influences in maintaining transcriptional specificity, and thus has a key role in cellular fitness. Collectively, all three accessory subunits, although dispensable under laboratory conditions, are often thought to be crucial for proper RNAP function. Herein we provide an overview of the available literature on each subunit, summarizing landmark findings that have deepened our understanding of these proteins and their function, and outline future challenges in understanding the role of these small subunits in the transcriptional process. PMID:25878038

  4. The effect of α2-δ and other accessory subunits on expression and properties of the calcium channel α1G

    PubMed Central

    Dolphin, A C; Wyatt, C N; Richards, J; Beattie, R E; Craig, P; Lee, J-H; Cribbs, L L; Volsen, S G; Perez-Reyes, E

    1999-01-01

    The effect has been examined of the accessory α2-δ and β subunits on the properties of α1G currents expressed in monkey COS-7 cells and Xenopus oocytes. In immunocytochemical experiments, the co-expression of α2-δ increased plasma membrane localization of expressed α1G and conversely, the heterologous expression of α1G increased immunostaining for endogenous α2-δ, suggesting an interaction between the two subunits. Heterologous expression of α2-δ together with α1G in COS-7 cells increased the amplitude of expressed α1G currents by about 2-fold. This finding was confirmed in the Xenopus oocyte expression system. The truncated δ construct did not increase α1G current amplitude, or increase its plasma membrane expression. This indicates that it is the exofacial α2 domain that is involved in the enhancement by α2-δ. β1b also produced an increase of functional expression of α1G, either in the absence or the presence of heterologously expressed α2-δ, whereas the other β subunits had much smaller effects. None of the accessory subunits had any marked influence on the voltage dependence or kinetics of the expressed α1G currents. These results therefore suggest that α2-δ and β1b interact with α1G to increase trafficking of, or stabilize, functional α1G channels expressed at the plasma membrane. PMID:10432337

  5. Expression of accessory colonization factor subunit A (ACFA) of Vibrio cholerae and ACFA fused to cholera toxin B subunit in transgenic tomato (Solanum lycopersicum).

    PubMed

    Sharma, Manoj Kumar; Jani, Dewal; Thungapathra, M; Gautam, J K; Meena, L S; Singh, Yogendra; Ghosh, Amit; Tyagi, Akhilesh Kumar; Sharma, Arun Kumar

    2008-05-20

    In earlier study from our group, cholera toxin B subunit had been expressed in tomato for developing a plant-based vaccine against cholera. In the present investigation, gene for accessory colonization factor (acf) subunit A, earlier reported to be essential for efficient colonization in the intestine, has been expressed in Escherichia coli as well as tomato plants. Gene encoding for a chimeric protein having a fusion of cholera toxin B subunit and accessory colonization factor A was also expressed in tomato to generate more potent combinatorial antigen. CaMV35S promoter with a duplicated enhancer sequence was used for expression of these genes in tomato. Integration of transgenes into tomato genome was confirmed by PCR and Southern hybridization. Expression of the genes was confirmed at transcript and protein levels. Accessory colonization factor A and cholera toxin B subunit fused to this protein accumulated up to 0.25% and 0.08% of total soluble protein, respectively, in the fruits of transgenic plants. Whereas protein purified from E. coli, in combination with cholera toxin B subunit can be used for development of conventional subunit vaccine, tomato fruits expressing these proteins can be used together with tomato plants expressing cholera toxin B subunit for development of oral vaccine against cholera.

  6. Elimination of fast inactivation in Kv4 A-type potassium channels by an auxiliary subunit domain.

    PubMed

    Holmqvist, Mats H; Cao, Jie; Hernandez-Pineda, Ricardo; Jacobson, Michael D; Carroll, Karen I; Sung, M Amy; Betty, Maria; Ge, Pei; Gilbride, Kevin J; Brown, Melissa E; Jurman, Mark E; Lawson, Deborah; Silos-Santiago, Inmaculada; Xie, Yu; Covarrubias, Manuel; Rhodes, Kenneth J; Distefano, Peter S; An, W Frank

    2002-01-22

    The Kv4 A-type potassium currents contribute to controlling the frequency of slow repetitive firing and back-propagation of action potentials in neurons and shape the action potential in heart. Kv4 currents exhibit rapid activation and inactivation and are specifically modulated by K-channel interacting proteins (KChIPs). Here we report the discovery and functional characterization of a modular K-channel inactivation suppressor (KIS) domain located in the first 34 aa of an additional KChIP (KChIP4a). Coexpression of KChIP4a with Kv4 alpha-subunits abolishes fast inactivation of the Kv4 currents in various cell types, including cerebellar granule neurons. Kinetic analysis shows that the KIS domain delays Kv4.3 opening, but once the channel is open, it disrupts rapid inactivation and slows Kv4.3 closing. Accordingly, KChIP4a increases the open probability of single Kv4.3 channels. The net effects of KChIP4a and KChIP1-3 on Kv4 gating are quite different. When both KChIP4a and KChIP1 are present, the Kv4.3 current shows mixed inactivation profiles dependent on KChIP4a/KChIP1 ratios. The KIS domain effectively converts the A-type Kv4 current to a slowly inactivating delayed rectifier-type potassium current. This conversion is opposite to that mediated by the Kv1-specific "ball" domain of the Kv beta 1 subunit. Together, these results demonstrate that specific auxiliary subunits with distinct functions actively modulate gating of potassium channels that govern membrane excitability.

  7. Auxiliary KChIP4a Suppresses A-type K+ Current through Endoplasmic Reticulum (ER) Retention and Promoting Closed-state Inactivation of Kv4 Channels*

    PubMed Central

    Tang, Yi-Quan; Liang, Ping; Zhou, Jingheng; Lu, Yanxin; Lei, Lei; Bian, Xiling; Wang, KeWei

    2013-01-01

    In the brain and heart, auxiliary Kv channel-interacting proteins (KChIPs) co-assemble with pore-forming Kv4 α-subunits to form a native K+ channel complex and regulate the expression and gating properties of Kv4 currents. Among the KChIP1–4 members, KChIP4a exhibits a unique N terminus that is known to suppress Kv4 function, but the underlying mechanism of Kv4 inhibition remains unknown. Using a combination of confocal imaging, surface biotinylation, and electrophysiological recordings, we identified a novel endoplasmic reticulum (ER) retention motif, consisting of six hydrophobic and aliphatic residues, 12–17 (LIVIVL), within the KChIP4a N-terminal KID, that functions to reduce surface expression of Kv4-KChIP complexes. This ER retention capacity is transferable and depends on its flanking location. In addition, adjacent to the ER retention motif, the residues 19–21 (VKL motif) directly promote closed-state inactivation of Kv4.3, thus leading to an inhibition of channel current. Taken together, our findings demonstrate that KChIP4a suppresses A-type Kv4 current via ER retention and enhancement of Kv4 closed-state inactivation. PMID:23576435

  8. Auxiliary KChIP4a suppresses A-type K+ current through endoplasmic reticulum (ER) retention and promoting closed-state inactivation of Kv4 channels.

    PubMed

    Tang, Yi-Quan; Liang, Ping; Zhou, Jingheng; Lu, Yanxin; Lei, Lei; Bian, Xiling; Wang, KeWei

    2013-05-24

    In the brain and heart, auxiliary Kv channel-interacting proteins (KChIPs) co-assemble with pore-forming Kv4 α-subunits to form a native K(+) channel complex and regulate the expression and gating properties of Kv4 currents. Among the KChIP1-4 members, KChIP4a exhibits a unique N terminus that is known to suppress Kv4 function, but the underlying mechanism of Kv4 inhibition remains unknown. Using a combination of confocal imaging, surface biotinylation, and electrophysiological recordings, we identified a novel endoplasmic reticulum (ER) retention motif, consisting of six hydrophobic and aliphatic residues, 12-17 (LIVIVL), within the KChIP4a N-terminal KID, that functions to reduce surface expression of Kv4-KChIP complexes. This ER retention capacity is transferable and depends on its flanking location. In addition, adjacent to the ER retention motif, the residues 19-21 (VKL motif) directly promote closed-state inactivation of Kv4.3, thus leading to an inhibition of channel current. Taken together, our findings demonstrate that KChIP4a suppresses A-type Kv4 current via ER retention and enhancement of Kv4 closed-state inactivation.

  9. Dendritic A-type potassium channel subunit expression in CA1 hippocampal interneurons.

    PubMed

    Menegola, M; Misonou, H; Vacher, H; Trimmer, J S

    2008-06-26

    Voltage-gated potassium (Kv) channels are important and diverse determinants of neuronal excitability and exhibit specific expression patterns throughout the brain. Among Kv channels, Kv4 channels are major determinants of somatodendritic A-type current and are essential in controlling the amplitude of backpropagating action potentials (BAPs) into neuronal dendrites. BAPs have been well studied in a variety of neurons, and have been recently described in hippocampal and cortical interneurons, a heterogeneous population of GABAergic inhibitory cells that regulate activity of principal cells and neuronal networks. We used well-characterized mouse monoclonal antibodies against the Kv4.3 and potassium channel interacting protein (KChIP) 1 subunits of A-type Kv channels, and antibodies against different interneuron markers in single- and double-label immunohistochemistry experiments to analyze the expression patterns of Kv4.3 and KChIP1 in hippocampal Ammon's horn (CA1) neurons. Immunohistochemistry was performed on 40 mum rat brain sections using nickel-enhanced diaminobenzidine staining or multiple-label immunofluorescence. Our results show that Kv4.3 and KChIP1 component subunits of A-type channels are co-localized in the soma and dendrites of a large number of GABAergic hippocampal interneurons. These subunits co-localize extensively but not completely with markers defining the four major interneuron subpopulations tested (parvalbumin, calbindin, calretinin, and somatostatin). These results suggest that CA1 hippocampal interneurons can be divided in two groups according to the expression of Kv4.3/KChIP1 channel subunits. Antibodies against Kv4.3 and KChIP1 represent an important new tool for identifying a subpopulation of hippocampal interneurons with a unique dendritic A-type channel complement and ability to control BAPs.

  10. Reductions in the Cardiac Transient Outward K+ Current Ito Caused by Chronic β-Adrenergic Receptor Stimulation Are Partly Rescued by Inhibition of Nuclear Factor κB.

    PubMed

    Panama, Brian K; Korogyi, Adam S; Aschar-Sobbi, Roozbeh; Oh, Yena; Gray, Charles B B; Gang, Hongying; Brown, Joan Heller; Kirshenbaum, Lorrie A; Backx, Peter H

    2016-02-19

    The fast transient outward potassium current (Ito,f) plays a critical role in the electrical and contractile properties of the myocardium. Ito,f channels are formed by the co-assembly of the pore-forming α-subunits, Kv4.2 and Kv4.3, together with the accessory β-subunit KChIP2. Reductions of Ito,f are common in the diseased heart, which is also associated with enhanced stimulation of β-adrenergic receptors (β-ARs). We used cultured neonatal rat ventricular myocytes to examine how chronic β-AR stimulation decreases Ito,f. To determine which downstream pathways mediate these Ito,f changes, adenoviral infections were used to inhibit CaMKIIδc, CaMKIIδb, calcineurin, or nuclear factor κB (NF-κB). We observed that chronic β-AR stimulation with isoproterenol (ISO) for 48 h reduced Ito,f along with mRNA expression of all three of its subunits (Kv4.2, Kv4.3, and KChIP2). Inhibiting either CaMKIIδc nor CaMKIIδb did not prevent the ISO-mediated Ito,f reductions, even though CaMKIIδc and CaMKIIδb clearly regulated Ito,f and the mRNA expression of its subunits. Likewise, calcineurin inhibition did not prevent the Ito,f reductions induced by β-AR stimulation despite strongly modulating Ito,f and subunit mRNA expression. In contrast, NF-κB inhibition partly rescued the ISO-mediated Ito,f reductions in association with restoration of KChIP2 mRNA expression. Consistent with these observations, KChIP2 promoter activity was reduced by p65 as well as β-AR stimulation. In conclusion, NF-κB, and not CaMKIIδ or calcineurin, partly mediates the Ito,f reductions induced by chronic β-AR stimulation. Both mRNA and KChIP2 promoter data suggest that the ISO-induced Ito,f reductions are, in part, mediated through reduced KChIP2 transcription caused by NF-κB activation. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  11. Human Pol ζ purified with accessory subunits is active in translesion DNA synthesis and complements Pol η in cisplatin bypass.

    PubMed

    Lee, Young-Sam; Gregory, Mark T; Yang, Wei

    2014-02-25

    DNA polymerase ζ (Pol ζ) is a eukaryotic B-family DNA polymerase that specializes in translesion synthesis and is essential for normal embryogenesis. At a minimum, Pol ζ consists of a catalytic subunit Rev3 and an accessory subunit Rev7. Mammalian Rev3 contains >3,000 residues and is twice as large as the yeast homolog. To date, no vertebrate Pol ζ has been purified for biochemical characterization. Here we report purification of a series of human Rev3 deletion constructs expressed in HEK293 cells and identification of a minimally catalytically active human Pol ζ variant. With a tagged form of an active Pol ζ variant, we isolated two additional accessory subunits of human Pol ζ, PolD2 and PolD3. The purified four-subunit Pol ζ4 (Rev3-Rev7-PolD2-PolD3) is much more efficient and more processive at bypassing a 1,2-intrastrand d(GpG)-cisplatin cross-link than the two-subunit Pol ζ2 (Rev3-Rev7). We show that complete bypass of cisplatin lesions requires Pol η to insert dCTP opposite the 3' guanine and Pol ζ4 to extend the primers.

  12. Human Pol ζ purified with accessory subunits is active in translesion DNA synthesis and complements Pol η in cisplatin bypass

    PubMed Central

    Lee, Young-Sam; Gregory, Mark T.; Yang, Wei

    2014-01-01

    DNA polymerase ζ (Pol ζ) is a eukaryotic B-family DNA polymerase that specializes in translesion synthesis and is essential for normal embryogenesis. At a minimum, Pol ζ consists of a catalytic subunit Rev3 and an accessory subunit Rev7. Mammalian Rev3 contains >3,000 residues and is twice as large as the yeast homolog. To date, no vertebrate Pol ζ has been purified for biochemical characterization. Here we report purification of a series of human Rev3 deletion constructs expressed in HEK293 cells and identification of a minimally catalytically active human Pol ζ variant. With a tagged form of an active Pol ζ variant, we isolated two additional accessory subunits of human Pol ζ, PolD2 and PolD3. The purified four-subunit Pol ζ4 (Rev3–Rev7–PolD2–PolD3) is much more efficient and more processive at bypassing a 1,2-intrastrand d(GpG)-cisplatin cross-link than the two-subunit Pol ζ2 (Rev3–Rev7). We show that complete bypass of cisplatin lesions requires Pol η to insert dCTP opposite the 3′ guanine and Pol ζ4 to extend the primers. PMID:24449906

  13. Ternary Kv4.2 channels recapitulate voltage-dependent inactivation kinetics of A-type K+ channels in cerebellar granule neurons.

    PubMed

    Amarillo, Yimy; De Santiago-Castillo, Jose A; Dougherty, Kevin; Maffie, Jonathon; Kwon, Elaine; Covarrubias, Manuel; Rudy, Bernardo

    2008-04-15

    Kv4 channels mediate most of the somatodendritic subthreshold operating A-type current (I(SA)) in neurons. This current plays essential roles in the regulation of spike timing, repetitive firing, dendritic integration and plasticity. Neuronal Kv4 channels are thought to be ternary complexes of Kv4 pore-forming subunits and two types of accessory proteins, Kv channel interacting proteins (KChIPs) and the dipeptidyl-peptidase-like proteins (DPPLs) DPPX (DPP6) and DPP10. In heterologous cells, ternary Kv4 channels exhibit inactivation that slows down with increasing depolarization. Here, we compared the voltage dependence of the inactivation rate of channels expressed in heterologous mammalian cells by Kv4.2 proteins with that of channels containing Kv4.2 and KChIP1, Kv4.2 and DPPX-S, or Kv4.2, KChIP1 and DPPX-S, and found that the relation between inactivation rate and membrane potential is distinct for these four conditions. Moreover, recordings from native neurons showed that the inactivation kinetics of the I(SA) in cerebellar granule neurons has voltage dependence that is remarkably similar to that of ternary Kv4 channels containing KChIP1 and DPPX-S proteins in heterologous cells. The fact that this complex and unique behaviour (among A-type K(+) currents) is observed in both the native current and the current expressed in heterologous cells by the ternary complex containing Kv4, DPPX and KChIP proteins supports the hypothesis that somatically recorded native Kv4 channels in neurons include both types of accessory protein. Furthermore, quantitative global kinetic modelling showed that preferential closed-state inactivation and a weakly voltage-dependent opening step can explain the slowing of the inactivation rate with increasing depolarization. Therefore, it is likely that preferential closed-state inactivation is the physiological mechanism that regulates the activity of both ternary Kv4 channel complexes and native I(SA)-mediating channels.

  14. Residues within the myristoylation motif determine intracellular targeting of the neuronal Ca2+ sensor protein KChIP1 to post-ER transport vesicles and traffic of Kv4 K+ channels.

    PubMed

    O'Callaghan, Dermott W; Hasdemir, Burcu; Leighton, Mark; Burgoyne, Robert D

    2003-12-01

    KChIPs (K+ channel interacting proteins) regulate the function of A-type Kv4 potassium channels by modifying channel properties and by increasing their cell surface expression. We have explored factors affecting the localisation of Kv4.2 and the targeting of KChIP1 and other NCS proteins by using GFP-variant fusion proteins expressed in HeLa cells. ECFP-Kv4.2 expressed alone was not retained in the ER but reached the Golgi complex. In cells co-expressing ECFP-Kv4.2 and KChIP1-EYFP, the two proteins were co-localised and were mainly present on the plasma membrane. When KChIP1-EYFP was expressed alone it was instead targeted to punctate structures. This was distinct from the localisation of the NCS proteins NCS-1 and hippocalcin, which were targeted to the trans-Golgi network (TGN) and plasma membrane. The membrane localisation of each NCS protein required myristoylation and minimal myristoylation motifs of hippocalcin or KChIP1 were sufficient to target fusion proteins to either TGN/plasma membrane or to punctate structures. The existence of targeting information within the N-terminal motifs was confirmed by mutagenesis of residues corresponding to three conserved basic amino acids in hippocalcin and NCS-1 at positions 3, 7 and 9. Residues at these positions determined intracellular targeting to the different organelles. Myristoylation and correct targeting of KChIP1 was required for the efficient traffic of ECFP-Kv4.2 to the plasma membrane. Expression of KChIP1(1-11)-EYFP resulted in the formation of enlarged structures that were positive for ERGIC-53 and beta-COP. ECFP-Kv4.2 was also accumulated in these structures suggesting that KChIP1(1-11)-EYFP inhibited traffic out of the ERGIC. We suggest that KChIP1 is targeted by its myristoylation motif to post-ER transport vesicles where it could interact with and regulate the traffic of Kv4 channels to the plasma membrane under the influence of localised Ca2+ signals.

  15. Conserved Kv4 N-terminal domain critical for effects of Kv channel-interacting protein 2.2 on channel expression and gating.

    PubMed

    Bähring, R; Dannenberg, J; Peters, H C; Leicher, T; Pongs, O; Isbrandt, D

    2001-06-29

    Association of Kv channel-interacting proteins (KChIPs) with Kv4 channels leads to modulation of these A-type potassium channels (An, W. F., Bowlby, M. R., Betty, M., Cao, J., Ling, H. P., Mendoza, G., Hinson, J. W., Mattsson, K. I., Strassle, B. W., Trimmer, J. S., and Rhodes, K. J. (2000) Nature 403, 553-556). We cloned a KChIP2 splice variant (KChIP2.2) from human ventricle. In comparison with KChIP2.1, coexpression of KChIP2.2 with human Kv4 channels in mammalian cells slowed the onset of Kv4 current inactivation (2-3-fold), accelerated the recovery from inactivation (5-7-fold), and shifted Kv4 steady-state inactivation curves by 8-29 mV to more positive potentials. The features of Kv4.2/KChIP2.2 currents closely resemble those of cardiac rapidly inactivating transient outward currents. KChIP2.2 stimulated the Kv4 current density in Chinese hamster ovary cells by approximately 55-fold. This correlated with a redistribution of immunoreactivity from perinuclear areas to the plasma membrane. Increased Kv4 cell-surface expression and current density were also obtained in the absence of KChIP2.2 when the highly conserved proximal Kv4 N terminus was deleted. The same domain is required for association of KChIP2.2 with Kv4 alpha-subunits. We propose that an efficient transport of Kv4 channels to the cell surface depends on KChIP binding to the Kv4 N-terminal domain. Our data suggest that the binding is necessary, but not sufficient, for the functional activity of KChIPs.

  16. Impact of Ancillary Subunits on Ventricular Repolarization

    PubMed Central

    Abbott, Geoffrey W.; Xu, Xianghua; Roepke, Torsten K.

    2007-01-01

    spatial Kv current variation, e.g. KChIP2 and the epicardial-endocardial Ito current density gradient. Indeed, it is likely that most native ventricular Kv channels exhibit temporal and spatial heterogeneity of subunit composition, complicating both modeling of their functional impact on the ventricular action potential and design of specific current-targeted compounds. Here, we discuss current thinking and lines of experimentation aimed at resolving the complexities of the Kv channel complexes that repolarize the human ventricular myocardium. PMID:17993327

  17. β Subunits Control the Effects of Human Kv4.3 Potassium Channel Phosphorylation.

    PubMed

    Abbott, Geoffrey W

    2017-01-01

    The transient outward K + current, I to , activates early in the cardiac myocyte action potential, to begin repolarization. Human I to is generated primarily by two Kv4.3 potassium channel α subunit splice variants (Kv4.3L and Kv4.3S) that diverge only by a C-terminal, membrane-proximal, 19-residue stretch unique to Kv4.3L. Protein kinase C (PKC) phosphorylation of threonine 504 within the Kv4.3L-specific 19-residues mediates α-adrenergic inhibition of I to in human heart. Kv4.3 is regulated in human heart by various β subunits, including cytosolic KChIP2b and transmembrane KCNEs, yet their impact on the functional effects of human Kv4.3 phosphorylation has not been reported. Here, this gap in knowledge was addressed using human Kv4.3 splice variants, T504 mutants, and human β subunits. Subunits were co-expressed in Xenopus laevis oocytes and analyzed by two-electrode voltage-clamp, using phorbol 12-myristate 13-acetate (PMA) to stimulate PKC. Unexpectedly, KChIP2b removed the inhibitory effect of PKC on Kv4.3L (but not Kv4.3L threonine phosphorylation by PKC per-se ), while co-expression with KCNE2, but not KCNE4, restored PKC-dependent inhibition of Kv4.3L-KChIP2b to quantitatively resemble previously reported effects of α-adrenergic modulation of human ventricular I to . In addition, PKC accelerated recovery from inactivation of Kv4.3L-KChIP2b channels and, interestingly, of both Kv4.3L and Kv4.3S alone. Thus, β subunits regulate the response of human Kv4.3 to PKC phosphorylation and provide a potential mechanism for modifying the response of I to to α-adrenergic regulation in vivo .

  18. β Subunits Control the Effects of Human Kv4.3 Potassium Channel Phosphorylation

    PubMed Central

    Abbott, Geoffrey W.

    2017-01-01

    The transient outward K+ current, Ito, activates early in the cardiac myocyte action potential, to begin repolarization. Human Ito is generated primarily by two Kv4.3 potassium channel α subunit splice variants (Kv4.3L and Kv4.3S) that diverge only by a C-terminal, membrane-proximal, 19-residue stretch unique to Kv4.3L. Protein kinase C (PKC) phosphorylation of threonine 504 within the Kv4.3L-specific 19-residues mediates α-adrenergic inhibition of Ito in human heart. Kv4.3 is regulated in human heart by various β subunits, including cytosolic KChIP2b and transmembrane KCNEs, yet their impact on the functional effects of human Kv4.3 phosphorylation has not been reported. Here, this gap in knowledge was addressed using human Kv4.3 splice variants, T504 mutants, and human β subunits. Subunits were co-expressed in Xenopus laevis oocytes and analyzed by two-electrode voltage-clamp, using phorbol 12-myristate 13-acetate (PMA) to stimulate PKC. Unexpectedly, KChIP2b removed the inhibitory effect of PKC on Kv4.3L (but not Kv4.3L threonine phosphorylation by PKC per-se), while co-expression with KCNE2, but not KCNE4, restored PKC-dependent inhibition of Kv4.3L-KChIP2b to quantitatively resemble previously reported effects of α-adrenergic modulation of human ventricular Ito. In addition, PKC accelerated recovery from inactivation of Kv4.3L-KChIP2b channels and, interestingly, of both Kv4.3L and Kv4.3S alone. Thus, β subunits regulate the response of human Kv4.3 to PKC phosphorylation and provide a potential mechanism for modifying the response of Ito to α-adrenergic regulation in vivo. PMID:28919864

  19. Distinct cellular distributions of Kv4 pore-forming and auxiliary subunits in rat dorsal root ganglion neurons.

    PubMed

    Matsuyoshi, Hiroko; Takimoto, Koichi; Yunoki, Takakazu; Erickson, Vickie L; Tyagi, Pradeep; Hirao, Yoshihiko; Wanaka, Akio; Yoshimura, Naoki

    2012-09-17

    Dorsal root ganglia contain heterogeneous populations of primary afferent neurons that transmit various sensory stimuli. This functional diversity may be correlated with differential expression of voltage-gated K(+) (Kv) channels. Here, we examine cellular distributions of Kv4 pore-forming and ancillary subunits that are responsible for fast-inactivating A-type K(+) current. Expression pattern of Kv α-subunit, β-subunit and auxiliary subunit was investigated using immunohistochemistry, in situ hybridization and RT-PCR technique. The two pore-forming subunits Kv4.1 and Kv4.3 show distinct cellular distributions: Kv4.3 is predominantly in small-sized C-fiber neurons, whereas Kv4.1 is seen in DRG neurons in various sizes. Furthermore, the two classes of Kv4 channel auxiliary subunits are also distributed in different-sized cells. KChIP3 is the only significantly expressed Ca(2+)-binding cytosolic ancillary subunit in DRGs and present in medium to large-sized neurons. The membrane-spanning auxiliary subunit DPP6 is seen in a large number of DRG neurons in various sizes, whereas DPP10 is restricted in small-sized neurons. Distinct combinations of Kv4 pore-forming and auxiliary subunits may constitute A-type channels in DRG neurons with different physiological roles. Kv4.1 subunit, in combination with KChIP3 and/or DPP6, form A-type K(+) channels in medium to large-sized A-fiber DRG neurons. In contrast, Kv4.3 and DPP10 may contribute to A-type K(+) current in non-peptidergic, C-fiber somatic afferent neurons. Copyright © 2012 Elsevier Inc. All rights reserved.

  20. Potential role of Arabidopsis PHP as an accessory subunit of the PAF1 transcriptional cofactor.

    PubMed

    Park, Sunchung; Ek-Ramos, Maria Julissa; Oh, Sookyung; van Nocker, Steven

    2011-08-01

    Paf1C is a transcriptional cofactor that has been implicated in various transcription-associated mechanisms spanning initiation, elongation and RNA processing, and is important for multiple aspects of development in Arabidopsis. Our recent studies suggest Arabidopsis Paf1C is crucial for proper regulation of genes within H3K27me3-enriched chromatin, and that a protein named PHP may act as an accessory subunit of Paf1C that promotes this function.

  1. IKs channels open slowly because KCNE1 accessory subunits slow the movement of S4 voltage sensors in KCNQ1 pore-forming subunits

    PubMed Central

    Ruscic, Katarina J.; Miceli, Francesco; Villalba-Galea, Carlos A.; Dai, Hui; Mishina, Yukiko; Bezanilla, Francisco; Goldstein, Steve A. N.

    2013-01-01

    Human IKs channels activate slowly with the onset of cardiac action potentials to repolarize the myocardium. IKs channels are composed of KCNQ1 (Q1) pore-forming subunits that carry S4 voltage-sensor segments and KCNE1 (E1) accessory subunits. Together, Q1 and E1 subunits recapitulate the conductive and kinetic properties of IKs. How E1 modulates Q1 has been unclear. Investigators have variously posited that E1 slows the movement of S4 segments, slows opening and closing of the conduction pore, or modifies both aspects of electromechanical coupling. Here, we show that Q1 gating current can be resolved in the absence of E1, but not in its presence, consistent with slowed movement of the voltage sensor. E1 was directly demonstrated to slow S4 movement with a fluorescent probe on the Q1 voltage sensor. Direct correlation of the kinetics of S4 motion and ionic current indicated that slowing of sensor movement by E1 was both necessary and sufficient to determine the slow-activation time course of IKs. PMID:23359697

  2. The Pseudorabies Virus DNA Polymerase Accessory Subunit UL42 Directs Nuclear Transport of the Holoenzyme

    PubMed Central

    Wang, Yi-Ping; Du, Wen-Juan; Huang, Li-Ping; Wei, Yan-Wu; Wu, Hong-Li; Feng, Li; Liu, Chang-Ming

    2016-01-01

    Pseudorabies virus (PRV) DNA replication occurs in the nuclei of infected cells and requires the viral DNA polymerase. The PRV DNA polymerase comprises a catalytic subunit, UL30, and an accessory subunit, UL42, that confers processivity to the enzyme. Its nuclear localization is a prerequisite for its enzymatic function in the initiation of viral DNA replication. However, the mechanisms by which the PRV DNA polymerase holoenzyme enters the nucleus have not been determined. In this study, we characterized the nuclear import pathways of the PRV DNA polymerase catalytic and accessory subunits. Immunofluorescence analysis showed that UL42 localizes independently in the nucleus, whereas UL30 alone predominantly localizes in the cytoplasm. Intriguingly, the localization of UL30 was completely shifted to the nucleus when it was coexpressed with UL42, demonstrating that nuclear transport of UL30 occurs in an UL42-dependent manner. Deletion analysis and site-directed mutagenesis of the two proteins showed that UL42 contains a functional and transferable bipartite nuclear localization signal (NLS) at amino acids 354–370 and that K354, R355, and K367 are important for the NLS function, whereas UL30 has no NLS. Coimmunoprecipitation assays verified that UL42 interacts with importins α3 and α4 through its NLS. In vitro nuclear import assays demonstrated that nuclear accumulation of UL42 is a temperature- and energy-dependent process and requires both importins α and β, confirming that UL42 utilizes the importin α/β-mediated pathway for nuclear entry. In an UL42 NLS-null mutant, the UL42/UL30 heterodimer was completely confined to the cytoplasm when UL42 was coexpressed with UL30, indicating that UL30 utilizes the NLS function of UL42 for its translocation into the nucleus. Collectively, these findings suggest that UL42 contains an importin α/β-mediated bipartite NLS that transports the viral DNA polymerase holoenzyme into the nucleus in an in vitro expression system

  3. The role of calsenilin/DREAM/KChIP3 in contextual fear conditioning.

    PubMed

    Alexander, Jon C; McDermott, Carmel M; Tunur, Tumay; Rands, Vicky; Stelly, Claire; Karhson, Debra; Bowlby, Mark R; An, W Frank; Sweatt, J David; Schrader, Laura A

    2009-03-01

    Potassium channel interacting proteins (KChIPs) are members of a family of calcium binding proteins that interact with Kv4 potassium (K(+)) channel primary subunits and also act as transcription factors. The Kv4 subunit is a primary K(+) channel pore-forming subunit, which contributes to the somatic and dendritic A-type currents throughout the nervous system. These A-type currents play a key role in the regulation of neuronal excitability and dendritic processing of incoming synaptic information. KChIP3 is also known as calsenilin and as the transcription factor, downstream regulatory element antagonist modulator (DREAM), which regulates a number of genes including prodynorphin. KChIP3 and Kv4 primary channel subunits are highly expressed in hippocampus, an area of the brain important for learning and memory. Through its various functions, KChIP3 may play a role in the regulation of synaptic plasticity and learning and memory. We evaluated the role of KChIP3 in a hippocampus-dependent memory task, contextual fear conditioning. Male KChIP3 knockout (KO) mice showed significantly enhanced memory 24 hours after training as measured by percent freezing. In addition, we found that membrane association and interaction with Kv4.2 of KChIP3 protein was significantly decreased and nuclear KChIP3 expression was increased six hours after the fear conditioning training paradigm with no significant change in KChIP3 mRNA. In addition, prodynorphin mRNA expression was significantly decreased six hours after fear conditioning training in wild-type (WT) but not in KO animals. These data suggest a role for regulation of gene expression by KChIP3/DREAM/calsenilin in consolidation of contextual fear conditioning memories.

  4. Expression of Functional Human α6β2β3* Acetylcholine Receptors in Xenopus laevis Oocytes Achieved through Subunit Chimeras and Concatamers

    PubMed Central

    Kuryatov, Alexandre

    2011-01-01

    α6β2β3* acetylcholine receptors (AChRs) on dopaminergic neurons are important targets for drugs to treat nicotine addiction and Parkinson's disease. However, it has not been possible to efficiently express functional α6β2β3* AChRs in oocytes or transfected cells. α6/α3 subunit chimeras permit expression of functional AChRs and reveal that parts of the α6 M1 transmembrane domain and large cytoplasmic domain impair assembly. Concatameric subunits permit assembly of functional α6β2β3* AChRs with defined subunit compositions and subunit orders. Assembly of accessory subunits is limiting in formation of mature AChRs. A single linker between the β3 accessory subunit and an α4 or α6 subunit is sufficient to permit assembly of complex β3-(α4β2)(α6β2) or β3-(α6β2)(α4β2) AChRs. Concatameric pentamers such as β3-α6-β2-α4-β2 have been functionally characterized. α6β2β3* AChRs are sensitive to activation by drugs used for smoking cessation therapy (nicotine, varenicline, and cytisine) and by sazetidine. All these are partial agonists. (α6β2)(α4β2)β3 AChRs are most sensitive to agonists. (α6β2)2β3 AChRs have the greatest Ca2+ permeability. (α4β2)(α6β2)β3 AChRs are most efficiently transported to the cell surface, whereas (α6β2)2β3 AChRs are the least efficiently transported. Dopaminergic neurons may have special chaperones for assembling accessory subunits with α6 subunits and for transporting (α6β2)2β3 AChRs to the cell surface. Concatameric pentamers and pentamers formed from combinations of trimers, dimers, and monomers exhibit similar properties, indicating that the linkers between subunits do not alter their functional properties. For the first time, these concatamers allow analysis of functional properties of α6β2β3* AChRs. These concatamers should enable selection of drugs specific for α6β2β3* AChRs. PMID:20923852

  5. PKA modulation of Kv4.2-encoded A-type potassium channels requires formation of a supramolecular complex.

    PubMed

    Schrader, Laura A; Anderson, Anne E; Mayne, Amber; Pfaffinger, Paul J; Sweatt, John David

    2002-12-01

    A-type channels, encoded by the pore-forming alpha-subunits of the Kv4.x family, are particularly important in regulating membrane excitability in the CNS and the heart. Given the key role of modulation of A currents by kinases, we sought to investigate the protein structure-function relationships underlying the regulation of these currents by PKA. We have previously shown the existence of two PKA phosphorylation sites in the Kv4.2 sequence; therefore, we focused this study on the Kv4.2 primary subunit. In the present studies we made the surprising finding that PKA phosphorylation of the Kv4.2 alpha-subunit is necessary but not sufficient for channel modulation; channel modulation by PKA required the presence of an ancillary subunit, the K+ channel interacting protein (KChIP3). Therefore, these findings indicate a surprising complexity to kinase regulation of A currents, in that an interaction of two separate molecular events, alpha-subunit phosphorylation and the association of an ancillary subunit (KChIP3), are necessary for phosphorylation-dependent regulation of Kv4.2-encoded A channels by PKA. Overall, our studies indicate that PKA must of necessity act on a supramolecular complex of pore-forming alpha-subunits plus ancillary subunits to alter channel properties.

  6. Altered expression and localization of hippocampal A-type potassium channel subunits in the pilocarpine-induced model of temporal lobe epilepsy.

    PubMed

    Monaghan, M M; Menegola, M; Vacher, H; Rhodes, K J; Trimmer, J S

    2008-10-15

    Altered ion channel expression and/or function may contribute to the development of certain human epilepsies. In rats, systemic administration of pilocarpine induces a model of human temporal lobe epilepsy, wherein a brief period of status epilepticus (SE) triggers development of spontaneous recurrent seizures that appear after a latency of 2-3 weeks. Here we investigate changes in expression of A-type voltage-gated potassium (Kv) channels, which control neuronal excitability and regulate action potential propagation and neurotransmitter release, in the pilocarpine model of epilepsy. Using immunohistochemistry, we examined the expression of component subunits of somatodendritic (Kv4.2, Kv4.3, KChIPl and KChIP2) and axonal (Kv1.4) A-type Kv channels in hippocampi of pilocarpine-treated rats that entered SE. We found that Kv4.2, Kv4.3 and KChIP2 staining in the molecular layer of the dentate gyrus changes from being uniformly distributed across the molecular layer to concentrated in just the outer two-thirds. We also observed a loss of KChIP1 immunoreactive interneurons, and a reduction of Kv4.2 and KChIP2 staining in stratum radiatum of CA1. These changes begin to appear 1 week after pilocarpine treatment and persist or are enhanced at 4 and 12 weeks. As such, these changes in Kv channel distribution parallel the acquisition of recurrent spontaneous seizures as observed in this model. We also found temporal changes in Kv1.4 immunoreactivity matching those in Timm's stain, being expanded in stratum lucidum of CA3 and in the inner third of the dentate molecular layer. Among pilocarpine-treated rats, changes were only observed in those that entered SE. These changes in A-type Kv channel expression may contribute to hyperexcitability of dendrites in the associated hippocampal circuits as observed in previous studies of the effects of pilocarpine-induced SE.

  7. Electrical remodelling maintains firing properties in cortical pyramidal neurons lacking KCND2-encoded A-type K+ currents.

    PubMed

    Nerbonne, Jeanne M; Gerber, Benjamin R; Norris, Aaron; Burkhalter, Andreas

    2008-03-15

    Considerable experimental evidence has accumulated demonstrating a role for voltage-gated K(+) (Kv) channel pore-forming (alpha) subunits of the Kv4 subfamily in the generation of fast transient outward K(+), I(A), channels. Immunohistochemical data suggest that I(A) channels in hippocampal and cortical pyramidal neurons reflect the expression of homomeric Kv4.2 channels. The experiments here were designed to define directly the role of Kv4.2 in the generation of I(A) in cortical pyramidal neurons and to determine the functional consequences of the targeted deletion of Kv4.2 on the resting and active membrane properties of these cells. Whole-cell voltage-clamp recordings, obtained from visual cortical pyramidal neurons isolated from mice in which the KCND2 (Kv4.2) locus was disrupted (Kv4.2-/- mice), revealed that I(A) is indeed eliminated. In addition, the densities of other Kv current components, specifically I(K) and I(ss), are increased significantly (P < 0.001) in most ( approximately 80%) Kv4.2-/- cells. The deletion of KCND2 (Kv4.2) and the elimination of I(A) is also accompanied by the loss of the Kv4 channel accessory protein KChIP3, suggesting that in the absence of Kv4.2, the KChIP3 protein is targeted for degradation. The expression levels of several Kv alpha subunits (Kv4.3, Kv1.4, Kv2.1, Kv2.2), however, are not measurably altered in Kv4.2-/- cortices. Although I(A) is eliminated in Kv4.2-/- pyramidal neurons, the mean +/- s.e.m. current threshold for action potential generation and the waveforms of action potentials are indistinguishable from those recorded from wild-type cells. Repetitive firing is also maintained in Kv4.2-/- cortical pyramidal neurons, suggesting that the increased densities of I(K) and I(ss) compensate for the in vivo loss of I(A).

  8. Differential plasma membrane targeting of voltage-dependent calcium channel subunits expressed in a polarized epithelial cell line

    PubMed Central

    Brice, Nicola L; Dolphin, Annette C

    1999-01-01

    Voltage-dependent calcium channels (VDCCs) show a highly non-uniform distribution in many cell types, including neurons and other polarized secretory cells. We have examined whether this can be mimicked in a polarized epithelial cell line (Madin-Darby canine kidney), which has been used extensively to study the targeting of proteins. We expressed the VDCC α1A, α1B or α1C subunits either alone or in combination with accessory subunits α2-δ and the different β subunits, and examined their localization immunocytochemically. An α1 subunit was only targeted to the plasma membrane if co-expressed with the accessory subunits. The combination α1C/α2-δ and all β subunits was always localized predominantly to the basolateral membrane. It has been suggested that this is equivalent to somatodendritic targeting in neurons. In contrast, the α1B subunit was expressed at the apical membrane with all the accessory subunit combinations, by 24 h after microinjection. This membrane destination shows some parallels with axonal targeting in neurons. The α1A subunit was consistently observed at the apical membrane in the combinations α1A/α2-δ/β1b or β4. In contrast, when co-expressed with α2-δ/β2a, α1A was clearly targeted to the basolateral membrane. In conclusion, the VDCC α1 subunit appears to be the primary determinant for targeting the VDCC complex, but the β subunit can modify this destination, particularly for α1A. PMID:10066897

  9. Altered Expression and Localization of Hippocampal A-Type Potassium Channel Subunits in the Pilocarpine-Induced Model of Temporal Lobe Epilepsy

    PubMed Central

    Monaghan, Michael M.; Menegola, Milena; Vacher, Helene; Rhodes, Kenneth J.; Trimmer, James S.

    2010-01-01

    Summary Altered ion channel expression and/or function may contribute to the development of certain human epilepsies. In rats, systemic administration of pilocarpine induces a model of human temporal lobe epilepsy, wherein a brief period of status epilepticus (SE) triggers development of spontaneous recurrent seizures that appear after a latency of two-three weeks. Here we investigate changes in expression of A-type voltage-gated potassium (Kv) channels, which control neuronal excitability and regulate action potential propagation and neurotransmitter release, in the pilocarpine model of epilepsy. Using immunohistochemistry, we examined the expression of component subunits of somatodendritic (Kv4.2, Kv4.3, KChIPl and KChIP2) and axonal (Kv1.4) A-type Kv channels in hippocampi of pilocarpine-treated rats that entered SE. We found that Kv4.2, Kv4.3 and KChIP2 staining in the molecular layer of the dentate gyrus changes from being uniformly distributed across the molecular layer to concentrated in just the outer two-thirds. We also observed a loss of KChIP1 immunoreactive interneurons, and a reduction of Kv4.2 and KChIP2 staining in stratum radiatum of CA1. These changes begin to appear 1 week after pilocarpine treatment and persist or are enhanced at 4 and 12 weeks. As such, these changes in Kv channel distribution parallel the acquisition of recurrent spontaneous seizures as observed in this model. We also found temporal changes in Kv1.4 immunoreactivity matching those in Timm's stain, being expanded in stratum lucidum of CA3 and in the inner third of the dentate molecular layer. Among pilocarpine-treated rats, changes were only observed in those that entered SE. These changes in A-type Kv channel expression may contribute to hyperexcitability of dendrites in the associated hippocampal circuits as observed in previous studies of the effects of pilocarpine-induced SE. PMID:18727953

  10. Expression and high glucose-mediated regulation of K+ channel interacting protein 3 (KChIP3) and KV4 channels in retinal Müller glial cells.

    PubMed

    Chavira-Suárez, Erika; Sandoval, Alejandro; Felix, Ricardo; Lamas, Mónica

    2011-01-14

    Normal vision depends on the correct function of retinal neurons and glia and it is impaired in the course of diabetic retinopathy. Müller cells, the main glial cells of the retina, suffer morphological and functional alterations during diabetes participating in the pathological retinal dysfunction. Recently, we showed that Müller cells express the pleiotropic protein potassium channel interacting protein 3 (KChIP3), an integral component of the voltage-gated K(+) channels K(V)4. Here, we sought to analyze the role of KChIP3 in the molecular mechanisms underlying hyperglycemia-induced phenotypic changes in the glial elements of the retina. The expression and function of KChIp3 was analyzed in vitro in rat Müller primary cultures grown under control (5.6 mM) or high glucose (25 mM) (diabetic-like) conditions. We show the up-regulation of KChIP3 expression in Müller cell cultures under high glucose conditions and demonstrate a previously unknown interaction between the K(V)4 channel and KChIP3 in Müller cells. We show evidence for the expression of a 4-AP-sensitive transient outward voltage-gated K(+) current and an alteration in the inactivation of the macroscopic outward K(+) currents expressed in high glucose-cultured Müller cells. Our data support the notion that induction of KChIP3 and functional changes of K(V)4 channels in Müller cells could exert a physiological role in the onset of diabetic retinopathy. Copyright © 2010 Elsevier Inc. All rights reserved.

  11. Effect of Cavβ Subunits on Structural Organization of Cav1.2 Calcium Channels

    PubMed Central

    Duong, Son Q.; Thomas, Sam; Harry, Jo Beth; Patel, Chirag; Lao, Qi Zong; Soldatov, Nikolai M.

    2009-01-01

    Background Voltage-gated Cav1.2 calcium channels play a crucial role in Ca2+ signaling. The pore-forming α1C subunit is regulated by accessory Cavβ subunits, cytoplasmic proteins of various size encoded by four different genes (Cavβ1 - β4) and expressed in a tissue-specific manner. Methods and Results Here we investigated the effect of three major Cavβ types, β1b, β2d and β3, on the structure of Cav1.2 in the plasma membrane of live cells. Total internal reflection fluorescence microscopy showed that the tendency of Cav1.2 to form clusters depends on the type of the Cavβ subunit present. The highest density of Cav1.2 clusters in the plasma membrane and the smallest cluster size were observed with neuronal/cardiac β1b present. Cav1.2 channels containing β3, the predominant Cavβ subunit of vascular smooth muscle cells, were organized in a significantly smaller number of larger clusters. The inter- and intramolecular distances between α1C and Cavβ in the plasma membrane of live cells were measured by three-color FRET microscopy. The results confirm that the proximity of Cav1.2 channels in the plasma membrane depends on the Cavβ type. The presence of different Cavβ subunits does not result in significant differences in the intramolecular distance between the termini of α1C, but significantly affects the distance between the termini of neighbor α1C subunits, which varies from 67 Å with β1b to 79 Å with β3. Conclusions Thus, our results show that the structural organization of Cav1.2 channels in the plasma membrane depends on the type of Cavβ subunits present. PMID:19492014

  12. Modulation of A-type potassium channels by a family of calcium sensors.

    PubMed

    An, W F; Bowlby, M R; Betty, M; Cao, J; Ling, H P; Mendoza, G; Hinson, J W; Mattsson, K I; Strassle, B W; Trimmer, J S; Rhodes, K J

    2000-02-03

    In the brain and heart, rapidly inactivating (A-type) voltage-gated potassium (Kv) currents operate at subthreshold membrane potentials to control the excitability of neurons and cardiac myocytes. Although pore-forming alpha-subunits of the Kv4, or Shal-related, channel family form A-type currents in heterologous cells, these differ significantly from native A-type currents. Here we describe three Kv channel-interacting proteins (KChIPs) that bind to the cytoplasmic amino termini of Kv4 alpha-subunits. We find that expression of KChIP and Kv4 together reconstitutes several features of native A-type currents by modulating the density, inactivation kinetics and rate of recovery from inactivation of Kv4 channels in heterologous cells. All three KChIPs co-localize and co-immunoprecipitate with brain Kv4 alpha-subunits, and are thus integral components of native Kv4 channel complexes. The KChIPs have four EF-hand-like domains and bind calcium ions. As the activity and density of neuronal A-type currents tightly control responses to excitatory synaptic inputs, these KChIPs may regulate A-type currents, and hence neuronal excitability, in response to changes in intracellular calcium.

  13. Hippocampal A-type current and Kv4.2 channel modulation by the sulfonylurea compound NS5806.

    PubMed

    Witzel, Katrin; Fischer, Paul; Bähring, Robert

    2012-12-01

    We examined the effects of the sulfonylurea compound NS5806 on neuronal A-type channel function. Using whole-cell patch-clamp we studied the effects of NS5806 on the somatodendritic A-type current (I(SA)) in cultured hippocampal neurons and the currents mediated by Kv4.2 channels coexpressed with different auxiliary β-subunits, including both Kv channel interacting proteins (KChIPs) and dipeptidyl aminopeptidase-related proteins (DPPs), in HEK 293 cells. The amplitude of the I(SA) component in hippocampal neurons was reduced in the presence of 20 μM NS5806. I(SA) decay kinetics were slowed and the recovery kinetics accelerated, but the voltage dependence of steady-state inactivation was shifted to more negative potentials by NS5806. The peak amplitudes of currents mediated by ternary Kv4.2 channel complexes, associated with DPP6-S (short splice-variant) and either KChIP2, KChIP3 or KChIP4, were potentiated and their macroscopic inactivation slowed by NS5806, whereas the currents mediated by binary Kv4.2 channels, associated only with DPP6-S, were suppressed, and the NS5806-mediated slowing of macroscopic inactivation was less pronounced. Neither potentiation nor suppression and no effect on current decay kinetics in the presence of NS5806 were observed for Kv4.2 channels associated with KChIP3 and the N-type inactivation-conferring DPP6a splice-variant. For all recombinant channel complexes, NS5806 slowed the recovery from inactivation and shifted the voltage dependence of steady-state inactivation to more negative potentials. Our results demonstrate the activity of NS5806 on native I(SA) and possible molecular correlates in the form of recombinant Kv4.2 channels complexed with different KChIPs and DPPs, and they shed some light on the mechanism of NS5806 action. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Mutant POLG2 Disrupts DNA Polymerase γ Subunits and Causes Progressive External Ophthalmoplegia

    PubMed Central

    Longley, Matthew J.; Clark, Susanna; Yu Wai Man, Cynthia; Hudson, Gavin; Durham, Steve E.; Taylor, Robert W.; Nightingale, Simon; Turnbull, Douglass M.; Copeland, William C.; Chinnery, Patrick F.

    2006-01-01

    DNA polymerase γ (pol γ) is required to maintain the genetic integrity of the 16,569-bp human mitochondrial genome (mtDNA). Mutation of the nuclear gene for the catalytic subunit of pol γ (POLG) has been linked to a wide range of mitochondrial diseases involving mutation, deletion, and depletion of mtDNA. We describe a heterozygous dominant mutation (c.1352G→A/p.G451E) in POLG2, the gene encoding the p55 accessory subunit of pol γ, that causes progressive external ophthalmoplegia with multiple mtDNA deletions and cytochrome c oxidase (COX)–deficient muscle fibers. Biochemical characterization of purified, recombinant G451E-substituted p55 protein in vitro revealed incomplete stimulation of the catalytic subunit due to compromised subunit interaction. Although G451E p55 retains a wild-type ability to bind DNA, it fails to enhance the DNA-binding strength of the p140-p55 complex. In vivo, the disease most likely arises through haplotype insufficiency or heterodimerization of the mutated and wild-type proteins, which promote mtDNA deletions by stalling the DNA replication fork. The progressive accumulation of mtDNA deletions causes COX deficiency in muscle fibers and results in the clinical phenotype. PMID:16685652

  15. Beta3 subunits promote expression and nicotine-induced up-regulation of human nicotinic alpha6* nicotinic acetylcholine receptors expressed in transfected cell lines.

    PubMed

    Tumkosit, Prem; Kuryatov, Alexander; Luo, Jie; Lindstrom, Jon

    2006-10-01

    Nicotinic acetylcholine receptors (AChRs) containing alpha6 subunits are typically found at aminergic nerve endings where they play important roles in nicotine addiction and Parkinson's disease. alpha6* AChRs usually contain beta3 subunits. beta3 subunits are presumed to assemble only in the accessory subunit position within AChRs where they do not participate in forming acetylcholine binding sites. Assembly of subunits in the accessory position may be a critical final step in assembly of mature AChRs. Human alpha6 AChRs subtypes were permanently transfected into human tsA201 human embryonic kidney (HEK) cell lines. alpha6beta2beta3 and alpha6beta4beta3 cell lines were found to express much larger amounts of AChRs and were more sensitive to nicotine-induced increase in the amount of AChRs than were alpha6beta2 or alpha6beta4 cell lines. The increased sensitivity to nicotine-induced up-regulation was due not to a beta3-induced increase in affinity for nicotine but probably to a direct effect on assembly of AChR subunits. HEK cells express only a small amount of mature alpha6beta2 AChRs, but many of these subunits are on the cell surface. This contrasts with Xenopus laevis oocytes, which express a large amount of incorrectly assembled alpha6beta2 subunits that bind cholinergic ligands but form large amorphous intracellular aggregates. Monoclonal antibodies (mAbs) were made to the alpha6 and beta3 subunits to aid in the characterization of these AChRs. The alpha6 mAbs bind to epitopes C-terminal of the extracellular domain. These data demonstrate that both cell type and the accessory subunit beta3 can play important roles in alpha6* AChR expression, stability, and up-regulation by nicotine.

  16. Comparison of Voltage Gated K+ Currents in Arterial Myocytes with Heterologously Expressed K v Subunits.

    PubMed

    Cox, Robert H; Fromme, Samantha

    2016-12-01

    We have shown that three components contribute to functional voltage gated K + (K v ) currents in rat small mesenteric artery myocytes: (1) Kv1.2 plus Kv1.5 with Kvβ1.2 subunits, (2) Kv2.1 probably associated with Kv9.3 subunits, and (3) Kv7.4 subunits. To confirm and address subunit stoichiometry of the first two, we have compared the biophysical properties of K v currents in small mesenteric artery myocytes with those of K v subunits heterologously expressed in HEK293 cells using whole cell voltage clamp methods. Selective inhibitors of Kv1 (correolide, COR) and Kv2 (stromatoxin, ScTx) channels were used to separate these K v current components. Conductance-voltage and steady state inactivation data along with time constants of activation, inactivation, and deactivation of native K v components were generally well represented by those of Kv1.2-1.5-β1.2 and Kv2.1-9.3 channels. The slope of the steady state inactivation-voltage curve (availability slope) proved to be the most sensitive measure of accessory subunit presence. The availability slope curves exhibited a single peak for both native K v components. Availability slope curves for Kv1.2-1.5-β1.2 and Kv2.1-9.3 channels expressed in human embryonic kidney cells also exhibited a single peak that shifted to more depolarized voltages with increasing accessory to α subunit transfection ratio. Availability slope curves for SxTc-insensitive currents were similar to those of Kv1.2-1.5 expressed with Kvβ1.2 at a 1:5 molar ratio while curves for COR-insensitive currents closely resembled those of Kv2.1 expressed with Kv9.3 at a 1:1 molar ratio. These results support the suggested K v subunit combinations in small mesenteric artery, and further suggest that Kv1 α and Kvβ1.2 but not Kv2.1 and Kv9.3 subunits are present in a saturated (4:4) stoichiometry.

  17. Activation of renal ClC-K chloride channels depends on an intact N terminus of their accessory subunit barttin.

    PubMed

    Wojciechowski, Daniel; Thiemann, Stefan; Schaal, Christina; Rahtz, Alina; de la Roche, Jeanne; Begemann, Birgit; Becher, Toni; Fischer, Martin

    2018-06-01

    ClC-K channels belong to the CLC family of chloride channels and chloride/proton antiporters. They contribute to sodium chloride reabsorption in Henle's loop of the kidney and to potassium secretion into the endolymph by the stria vascularis of the inner ear. Their accessory subunit barttin stabilizes the ClC-K/barttin complex, promotes its insertion into the surface membrane, and turns the pore-forming subunits into a conductive state. Barttin mutations cause Bartter syndrome type IV, a salt-wasting nephropathy with sensorineural deafness. Here, studying ClC-K/barttin channels heterologously expressed in MDCK-II and HEK293T cells with confocal imaging and patch-clamp recordings, we demonstrate that the eight-amino-acids-long barttin N terminus is required for channel trafficking and activation. Deletion of the complete N terminus (Δ2-8 barttin) retained barttin and human hClC-Ka channels in intracellular compartments. Partial N-terminal deletions did not compromise subcellular hClC-Ka trafficking but drastically reduced current amplitudes. Sequence deletions encompassing Thr-6, Phe-7, or Arg-8 in barttin completely failed to activate hClC-Ka. Analyses of protein expression and whole-cell current noise revealed that inactive channels reside in the plasma membrane. Substituting the deleted N terminus with a polyalanine sequence was insufficient for recovering chloride currents, and single amino acid substitutions highlighted that the correct sequence is required for proper function. Fast and slow gate activation curves obtained from rat V166E rClC-K1/barttin channels indicated that mutant barttin fails to constitutively open the slow gate. Increasing expression of barttin over that of ClC-K partially recovered this insufficiency, indicating that N-terminal modifications of barttin alter both binding affinities and gating properties. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

  18. The role of accessory cells in polyclonal T cell activation. I. Both induction of interleukin 2 production and of interleukin 2 responsiveness by concanavalin A are accessory cell dependent.

    PubMed

    Hünig, T; Loos, M; Schimpl, A

    1983-01-01

    Recent studies from other laboratories have shown that concanavalin A (Con A) acts at two separate steps in polyclonal T cell activation: interleukin 2 (IL2) production, and induction of responsiveness to IL2. Using a combination of techniques for the depletion of accessory cells from lymph node T cells, we have investigated which of these steps, if not both, is responsible for the known requirement for accessory cells in the Con A response. It was found that with increasing T cell purification, first the ability is lost to produce sufficient levels of endogenous IL2, whereas induction of IL2 responsiveness can still take place. Further removal of accessory cells however yields a population of resting T cells that cannot be induced by Con A to become IL2-reactive. It was concluded that both IL2 production and induction of reactivity to IL2 are accessory cell-dependent events.

  19. Each Monomer of the Dimeric Accessory Protein for Human Mitochondrial DNA Polymerase Has a Distinct Role in Conferring Processivity*

    PubMed Central

    Lee, Young-Sam; Lee, Sujin; Demeler, Borries; Molineux, Ian J.; Johnson, Kenneth A.; Yin, Y. Whitney

    2010-01-01

    The accessory protein polymerase (pol) γB of the human mitochondrial DNA polymerase stimulates the synthetic activity of the catalytic subunit. pol γB functions by both accelerating the polymerization rate and enhancing polymerase-DNA interaction, thereby distinguishing itself from the accessory subunits of other DNA polymerases. The molecular basis for the unique functions of human pol γB lies in its dimeric structure, where the pol γB monomer proximal to pol γA in the holoenzyme strengthens the interaction with DNA, and the distal pol γB monomer accelerates the reaction rate. We further show that human pol γB exhibits a catalytic subunit- and substrate DNA-dependent dimerization. By duplicating the monomeric pol γB of lower eukaryotes, the dimeric mammalian proteins confer additional processivity to the holoenzyme polymerase. PMID:19858216

  20. Calmodulin-dependent gating of Ca(v)1.2 calcium channels in the absence of Ca(v)beta subunits.

    PubMed

    Ravindran, Arippa; Lao, Qi Zong; Harry, Jo Beth; Abrahimi, Parwiz; Kobrinsky, Evgeny; Soldatov, Nikolai M

    2008-06-10

    It is generally accepted that to generate calcium currents in response to depolarization, Ca(v)1.2 calcium channels require association of the pore-forming alpha(1C) subunit with accessory Ca(v)beta and alpha(2)delta subunits. A single calmodulin (CaM) molecule is tethered to the C-terminal alpha(1C)-LA/IQ region and mediates Ca2+-dependent inactivation of the channel. Ca(v)beta subunits are stably associated with the alpha(1C)-interaction domain site of the cytoplasmic linker between internal repeats I and II and also interact dynamically, in a Ca2+-dependent manner, with the alpha(1C)-IQ region. Here, we describe a surprising discovery that coexpression of exogenous CaM (CaM(ex)) with alpha(1C)/alpha(2)delta in COS1 cells in the absence of Ca(v)beta subunits stimulates the plasma membrane targeting of alpha(1C), facilitates calcium channel gating, and supports Ca2+-dependent inactivation. Neither real-time PCR with primers complementary to monkey Ca(v)beta subunits nor coimmunoprecipitation analysis with exogenous alpha(1C) revealed an induction of endogenous Ca(v)beta subunits that could be linked to the effect of CaM(ex). Coexpression of a calcium-insensitive CaM mutant CaM(1234) also facilitated gating of Ca(v)beta-free Ca(v)1.2 channels but did not support Ca2+-dependent inactivation. Our results show there is a functional matchup between CaM(ex) and Ca(v)beta subunits that, in the absence of Ca(v)beta, renders Ca2+ channel gating facilitated by CaM molecules other than the one tethered to LA/IQ to support Ca2+-dependent inactivation. Thus, coexpression of CaM(ex) creates conditions when the channel gating, voltage- and Ca2+-dependent inactivation, and plasma-membrane targeting occur in the absence of Ca(v)beta. We suggest that CaM(ex) affects specific Ca(v)beta-free conformations of the channel that are not available to endogenous CaM.

  1. Development of heart failure is independent of K+ channel-interacting protein 2 expression

    PubMed Central

    Speerschneider, Tobias; Grubb, Søren; Metoska, Artina; Olesen, Søren-Peter; Calloe, Kirstine; Thomsen, Morten B

    2013-01-01

    Abnormal ventricular repolarization in ion channelopathies and heart disease is a major cause of ventricular arrhythmias and sudden cardiac death. K+ channel-interacting protein 2 (KChIP2) expression is significantly reduced in human heart failure (HF), contributing to a loss of the transient outward K+ current (Ito). We aim to investigate the possible significance of a changed KChIP2 expression on the development of HF and proarrhythmia. Transverse aortic constrictions (TAC) and sham operations were performed in wild-type (WT) and KChIP2−/− mice. Echocardiography was performed before and every 2 weeks after the operation. Ten weeks post-surgery, surface ECG was recorded and we paced the heart in vivo to induce arrhythmias. Afterwards, tissue from the left ventricle was used for immunoblotting. Time courses of HF development were comparable in TAC-operated WT and KChIP2−/− mice. Ventricular protein expression of KChIP2 was reduced by 70% after 10 weeks TAC in WT mice. The amplitudes of the J and T waves were enlarged in KChIP2−/− control mice. Ventricular effective refractory period, RR, QRS and QT intervals were longer in mice with HF compared to sham-operated mice of either genotype. Pacing-induced ventricular tachycardia (VT) was observed in 5/10 sham-operated WT mice compared with 2/10 HF WT mice with HF. Interestingly, and contrary to previously published data, sham-operated KChIP2−/− mice were resistant to pacing-induced VT resulting in only 1/10 inducible mice. KChIP2−/− with HF mice had similar low vulnerability to inducible VT (1/9). Our results suggest that although KChIP2 is downregulated in HF, it is not orchestrating the development of HF. Moreover, KChIP2 affects ventricular repolarization and lowers arrhythmia susceptibility. Hence, downregulation of KChIP2 expression in HF may be antiarrhythmic in mice via reduction of the fast transient outward K+ current. PMID:24099801

  2. Specific Inhibition of Herpes Simplex Virus DNA Polymerase by Helical Peptides Corresponding to the Subunit Interface

    NASA Astrophysics Data System (ADS)

    Digard, Paul; Williams, Kevin P.; Hensley, Preston; Brooks, Ian S.; Dahl, Charles E.; Coen, Donald M.

    1995-02-01

    The herpes simplex virus DNA polymerase consists of two subunits-a catalytic subunit and an accessory subunit, UL42, that increases processivity. Mutations affecting the extreme C terminus of the catalytic subunit specifically disrupt subunit interactions and ablate virus replication, suggesting that new antiviral drugs could be rationally designed to interfere with polymerase heterodimerization. To aid design, we performed circular dichroism (CD) spectroscopy and analytical ultracentrifugation studies, which revealed that a 36-residue peptide corresponding to the C terminus of the catalytic subunit folds into a monomeric structure with partial α-helical character. CD studies of shorter peptides were consistent with a model where two separate regions of α-helix interact to form a hairpin-like structure. The 36-residue peptide and a shorter peptide corresponding to the C-terminal 18 residues blocked UL42-dependent long-chain DNA synthesis at concentrations that had no effect on synthesis by the catalytic subunit alone or by calf thymus DNA polymerase δ and its processivity factor. These peptides, therefore, represent a class of specific inhibitors of herpes simplex virus DNA polymerase that act by blocking accessory-subunit-dependent synthesis. These peptides or their structures may form the basis for the synthesis of clinically effective drugs.

  3. Subunit arrangement in P2X receptors.

    PubMed

    Jiang, Lin-Hua; Kim, Miran; Spelta, Valeria; Bo, Xuenong; Surprenant, Annmarie; North, R Alan

    2003-10-01

    ATP-gated ionotropic receptors (P2X receptors) are distributed widely in the nervous system. For example, a hetero-oligomeric receptor containing both P2X2 and P2X3 subunits is involved in primary afferent sensation. Each subunit has two membrane-spanning domains. We have used disulfide bond formation between engineered cysteines to demonstrate close proximity between the outer ends of the first transmembrane domain of one subunit and the second transmembrane domain of another. After expression in HEK 293 cells of such modified P2X2 or P2X4 subunits, the disulfide bond formation is evident because an ATP-evoked channel opening requires previous reduction with dithiothreitol. In the hetero-oligomeric P2X2/3 receptor the coexpression of doubly substituted subunits with wild-type partners allows us to deduce that the hetero-oligomeric channel contains adjacent P2X3 subunits but does not contain adjacent P2X2 subunits. The results suggest a "head-to-tail" subunit arrangement in the quaternary structure of P2X receptors and show that a trimeric P2X2/3 receptor would have the composition P2X2(P2X3)2.

  4. Mechanism of the modulation of Kv4:KChIP-1 channels by external K+.

    PubMed

    Kaulin, Yu A; De Santiago-Castillo, J A; Rocha, C A; Covarrubias, M

    2008-02-15

    In response to a prolonged membrane depolarization, inactivation autoregulates the activity of voltage-gated ion channels. Slow inactivation involving a localized constriction of the selectivity filter (P/C-type mechanism) is prevalent in many voltage-gated K(+) channels of the Kv1 subfamily. However, the generalization of this mechanism to other Kv channel subfamilies has remained uncertain and controversial. In agreement with a "foot-in-the-door" mechanism and the presence of ion-ion interactions in the pore, elevated external K(+) slows the development of P/C-type inactivation and accelerates its recovery. In sharp contrast and resembling the regulation of the hippocampal A-type K(+) current, we found that Kv4.x channels associated with KChIP-1 (an auxiliary subunit) exhibit accelerated inactivation and unaffected recovery from inactivation when exposed to elevated external K(+). This regulation depends on the ability of a permeant ion to enter the selectivity filter (K(+) = Rb(+) = NH4(+) > Cs(+) > Na(+)); and the apparent equilibrium dissociation constant of a single regulatory site is 8 mM for K(+). By applying a robust quantitative global kinetic modeling approach to all macroscopic properties over a 210-mV range of membrane potentials, we determined that elevated external K(+) inhibits unstable closed states outside the main activation pathway and thereby promotes preferential closed-state inactivation. These results suggest the presence of a vestigial and unstable P/C-type mechanism of inactivation in Kv4 channels and strengthen the concept of novel mechanisms of closed-state inactivation. Regulation of Kv4 channel inactivation by hyperkalemia may help to explain the pathophysiology of electrolyte imbalances in excitable tissues.

  5. Circadian rhythm in QT interval is preserved in mice deficient of potassium channel interacting protein 2.

    PubMed

    Gottlieb, Lisa A; Lubberding, Anniek; Larsen, Anders Peter; Thomsen, Morten B

    2017-01-01

    Potassium Channel Interacting Protein 2 (KChIP2) is suggested to be responsible for the circadian rhythm in repolarization duration, ventricular arrhythmias, and sudden cardiac death. We investigated the hypothesis that there is no circadian rhythm in QT interval in the absence of KChIP2. Implanted telemetric devices recorded electrocardiogram continuously for 5 days in conscious wild-type mice (WT, n = 9) and KChIP2 -/- mice (n = 9) in light:dark periods and in complete darkness. QT intervals were determined from all RR intervals and corrected for heart rate (QT 100 = QT/(RR/100) 1/2 ). Moreover, QT intervals were determined from complexes within the RR range of mean-RR ± 1% in the individual mouse (QT mean-RR ). We find that RR intervals are 125 ± 5 ms in WT and 123 ± 4 ms in KChIP2 -/- (p = 0.81), and QT intervals are 52 ± 1 and 52 ± 1 ms, respectively(p = 0.89). No ventricular arrhythmias or sudden cardiac deaths were observed. We find similar diurnal (light:dark) and circadian (darkness) rhythms of RR intervals in WT and KChIP2 -/- mice. Circadian rhythms in QT 100 intervals are present in both groups, but at physiological small amplitudes: 1.6 ± 0.2 and 1.0 ± 0.3 ms in WT and KChIP2 -/- , respectively (p = 0.15). A diurnal rhythm in QT 100 intervals was only found in WT mice. QT mean-RR intervals display clear diurnal and circadian rhythms in both WT and KChIP2 -/- . The amplitude of the circadian rhythm in QT mean-RR is 4.0 ± 0.3 and 3.1 ± 0.5 ms in WT and KChIP2 -/- , respectively (p = 0.16). In conclusion, KChIP2 expression does not appear to underlie the circadian rhythm in repolarization duration.

  6. Atypical properties of a conventional calcium channel beta subunit from the platyhelminth Schistosoma mansoni.

    PubMed

    Salvador-Recatalà, Vicenta; Schneider, Toni; Greenberg, Robert M

    2008-03-26

    The function of voltage-gated calcium (Cav) channels greatly depends on coupling to cytoplasmic accessory beta subunits, which not only promote surface expression, but also modulate gating and kinetic properties of the alpha1 subunit. Schistosomes, parasitic platyhelminths that cause schistosomiasis, express two beta subunit subtypes: a structurally conventional beta subunit and a variant beta subunit with unusual functional properties. We have previously characterized the functional properties of the variant Cavbeta subunit. Here, we focus on the modulatory phenotype of the conventional Cavbeta subunit (SmCavbeta) using the human Cav2.3 channel as the substrate for SmCavbeta and the whole-cell patch-clamp technique. The conventional Schistosoma mansoni Cavbeta subunit markedly increases Cav2.3 currents, slows macroscopic inactivation and shifts steady state inactivation in the hyperpolarizing direction. However, currents produced by Cav2.3 in the presence of SmCavbeta run-down to approximately 75% of their initial amplitudes within two minutes of establishing the whole-cell configuration. This suppressive effect was independent of Ca2+, but dependent on intracellular Mg2+-ATP. Additional experiments revealed that SmCavbeta lends the Cav2.3/SmCavbeta complex sensitivity to Na+ ions. A mutant version of the Cavbeta subunit lacking the first forty-six amino acids, including a string of twenty-two acidic residues, no longer conferred sensitivity to intracellular Mg2+-ATP and Na+ ions, while continuing to show wild type modulation of current amplitude and inactivation of Cav2.3. The data presented in this article provide insights into novel mechanisms employed by platyhelminth Cavbeta subunits to modulate voltage-gated Ca2+ currents that indicate interactions between the Ca2+ channel complex and chelated forms of ATP as well as Na+ ions. These results have potentially important implications for understanding previously unknown mechanisms by which platyhelminths and

  7. INTERIOR VIEW OF BATHROOM 2. SHOWING ORIGINAL TILE. CERAMIC ACCESSORIES, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR VIEW OF BATHROOM 2. SHOWING ORIGINAL TILE. CERAMIC ACCESSORIES, AND MARBLE THRESHOLD. VIEW FACING EAST. - Hickam Field, Officers' Housing Type G, 205 Seventh Street, Honolulu, Honolulu County, HI

  8. 14 CFR 29.1163 - Powerplant accessories.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Powerplant accessories. (a) Each engine mounted accessory must— (1) Be approved for mounting on the engine involved; (2) Use the provisions on the engine for mounting; and (3) Be sealed in such a way as to prevent contamination of the engine oil system and the accessory system. (b) Electrical equipment subject to arcing or...

  9. 14 CFR 29.1163 - Powerplant accessories.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Powerplant accessories. (a) Each engine mounted accessory must— (1) Be approved for mounting on the engine involved; (2) Use the provisions on the engine for mounting; and (3) Be sealed in such a way as to prevent contamination of the engine oil system and the accessory system. (b) Electrical equipment subject to arcing or...

  10. 14 CFR 29.1163 - Powerplant accessories.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Powerplant accessories. (a) Each engine mounted accessory must— (1) Be approved for mounting on the engine involved; (2) Use the provisions on the engine for mounting; and (3) Be sealed in such a way as to prevent contamination of the engine oil system and the accessory system. (b) Electrical equipment subject to arcing or...

  11. 14 CFR 29.1163 - Powerplant accessories.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Powerplant accessories. (a) Each engine mounted accessory must— (1) Be approved for mounting on the engine involved; (2) Use the provisions on the engine for mounting; and (3) Be sealed in such a way as to prevent contamination of the engine oil system and the accessory system. (b) Electrical equipment subject to arcing or...

  12. Pharmacological consequences of the coexpression of BK channel α and auxiliary β subunits

    PubMed Central

    Torres, Yolima P.; Granados, Sara T.; Latorre, Ramón

    2014-01-01

    Coded by a single gene (Slo1, KCM) and activated by depolarizing potentials and by a rise in intracellular Ca2+ concentration, the large conductance voltage- and Ca2+-activated K+ channel (BK) is unique among the superfamily of K+ channels. BK channels are tetramers characterized by a pore-forming α subunit containing seven transmembrane segments (instead of the six found in voltage-dependent K+ channels) and a large C terminus composed of two regulators of K+ conductance domains (RCK domains), where the Ca2+-binding sites reside. BK channels can be associated with accessory β subunits and, although different BK modulatory mechanisms have been described, greater interest has recently been placed on the role that the β subunits may play in the modulation of BK channel gating due to its physiological importance. Four β subunits have currently been identified (i.e., β1, β2, β3, and β4) and despite the fact that they all share the same topology, it has been shown that every β subunit has a specific tissue distribution and that they modify channel kinetics as well as their pharmacological properties and the apparent Ca2+ sensitivity of the α subunit in different ways. Additionally, different studies have shown that natural, endogenous, and synthetic compounds can modulate BK channels through β subunits. Considering the importance of these channels in different pathological conditions, such as hypertension and neurological disorders, this review focuses on the mechanisms by which these compounds modulate the biophysical properties of BK channels through the regulation of β subunits, as well as their potential therapeutic uses for diseases such as those mentioned above. PMID:25346693

  13. Pharmacological consequences of the coexpression of BK channel α and auxiliary β subunits.

    PubMed

    Torres, Yolima P; Granados, Sara T; Latorre, Ramón

    2014-01-01

    Coded by a single gene (Slo1, KCM) and activated by depolarizing potentials and by a rise in intracellular Ca(2+) concentration, the large conductance voltage- and Ca(2+)-activated K(+) channel (BK) is unique among the superfamily of K(+) channels. BK channels are tetramers characterized by a pore-forming α subunit containing seven transmembrane segments (instead of the six found in voltage-dependent K(+) channels) and a large C terminus composed of two regulators of K(+) conductance domains (RCK domains), where the Ca(2+)-binding sites reside. BK channels can be associated with accessory β subunits and, although different BK modulatory mechanisms have been described, greater interest has recently been placed on the role that the β subunits may play in the modulation of BK channel gating due to its physiological importance. Four β subunits have currently been identified (i.e., β1, β2, β3, and β4) and despite the fact that they all share the same topology, it has been shown that every β subunit has a specific tissue distribution and that they modify channel kinetics as well as their pharmacological properties and the apparent Ca(2+) sensitivity of the α subunit in different ways. Additionally, different studies have shown that natural, endogenous, and synthetic compounds can modulate BK channels through β subunits. Considering the importance of these channels in different pathological conditions, such as hypertension and neurological disorders, this review focuses on the mechanisms by which these compounds modulate the biophysical properties of BK channels through the regulation of β subunits, as well as their potential therapeutic uses for diseases such as those mentioned above.

  14. Heteromeric assembly of P2X subunits

    PubMed Central

    Saul, Anika; Hausmann, Ralf; Kless, Achim; Nicke, Annette

    2013-01-01

    Transcripts and/or proteins of P2X receptor (P2XR) subunits have been found in virtually all mammalian tissues. Generally more than one of the seven known P2X subunits have been identified in a given cell type. Six of the seven cloned P2X subunits can efficiently form functional homotrimeric ion channels in recombinant expression systems. This is in contrast to other ligand-gated ion channel families, such as the Cys-loop or glutamate receptors, where homomeric assemblies seem to represent the exception rather than the rule. P2XR mediated responses recorded from native tissues rarely match exactly the biophysical and pharmacological properties of heterologously expressed homomeric P2XRs. Heterotrimerization of P2X subunits is likely to account for this observed diversity. While the existence of heterotrimeric P2X2/3Rs and their role in physiological processes is well established, the composition of most other P2XR heteromers and/or the interplay between distinct trimeric receptor complexes in native tissues is not clear. After a description of P2XR assembly and the structure of the intersubunit ATP-binding site, this review summarizes the distribution of P2XR subunits in selected mammalian cell types and the biochemically and/or functionally characterized heteromeric P2XRs that have been observed upon heterologous co-expression of P2XR subunits. We further provide examples where the postulated heteromeric P2XRs have been suggested to occur in native tissues and an overview of the currently available pharmacological tools that have been used to discriminate between homo- and heteromeric P2XRs. PMID:24391538

  15. 14 CFR 25.1163 - Powerplant accessories.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Powerplant accessories. (a) Each engine mounted accessory must— (1) Be approved for mounting on the engine involved; (2) Use the provisions on the engine for mounting; and (3) Be sealed to prevent contamination of...

  16. Complex expression and localization of inactivating Kv channels in cultured hippocampal astrocytes.

    PubMed

    Bekar, Lane K; Loewen, Matthew E; Cao, Kun; Sun, Xianfeng; Leis, Jerome; Wang, Rui; Forsyth, George W; Walz, Wolfgang

    2005-03-01

    Voltage-gated potassium channels are well established as critical for setting action potential frequency, membrane potential, and neurotransmitter release in neurons. However, their role in the "nonexcitable" glial cell type is yet to be fully understood. We used whole cell current kinetics, pharmacology, immunocytochemistry, and RT-PCR to characterize A-type current in hippocampal astrocyte cultures to better understand its function. Pharmacological analysis suggests that approximately 70, 10, and <5% of total A current is associated with Kv4, Kv3, and Kv1 channels, respectively. In addition, pharmacology and kinetics provide evidence for a significant contribution of KChIP accessory proteins to astrocytic A-channel composition. Localization of the Shaw Kv3.4 channel to astrocytic processes and the Shal Kv4.3 channel to soma suggest that these channels serve a specific function. Given this complex A-type channel expression pattern, we assessed the role of A currents in membrane voltage oscillations in response to current injections. Although TEA-sensitive delayed-rectifying currents are involved in the extent of repolarization, 4-AP-sensitive A currents serve to increase the rate. As in neurons, this effect may enable astrocytes to respond rapidly to high-frequency synaptic events. Our results indicate that hippocampal astrocytes in vitro express multiple A-type Kv channel alpha-subunits with accessory, possibly Ca(2+)-sensitive, cytoplasmic subunits that appear to be specifically localized to subcellular membrane compartments. Function of these channels remains to be determined in a physiological setting. However, this study suggests that they enable astrocytes to respond rapidly with membrane voltage oscillations to high-frequency incoming signals, possibly synchronizing astrocyte function to neuronal activity.

  17. Regulation of human cardiac potassium channels by full-length KCNE3 and KCNE4.

    PubMed

    Abbott, Geoffrey W

    2016-12-06

    Voltage-gated potassium (Kv) channels comprise pore-forming α subunits and a multiplicity of regulatory proteins, including the cardiac-expressed and cardiac arrhythmia-linked transmembrane KCNE subunits. After recently uncovering novel, N-terminally extended (L) KCNE3 and KCNE4 isoforms and detecting their transcripts in human atrium, reported here are their functional effects on human cardiac Kv channel α subunits expressed in Xenopus laevis oocytes. As previously reported for short isoforms KCNE3S and KCNE4S, KCNE3L inhibited hERG; KCNE4L inhibited Kv1.1; neither form regulated the HCN1 pacemaker channel. Unlike KCNE4S, KCNE4L was a potent inhibitor of Kv4.2 and Kv4.3; co-expression of cytosolic β subunit KChIP2, which regulates Kv4 channels in cardiac myocytes, partially relieved Kv4.3 but not Kv4.2 inhibition. Inhibition of Kv4.2 and Kv4.3 by KCNE3L was weaker, and its inhibition of Kv4.2 abolished by KChIP2. KCNE3L and KCNE4L also exhibited subunit-specific effects on Kv4 channel complex inactivation kinetics, voltage dependence and recovery. Further supporting the potential physiological significance of the robust functional effects of KCNE4L on Kv4 channels, KCNE4L protein was detected in human atrium, where it co-localized with Kv4.3. The findings establish functional effects of novel human cardiac-expressed KCNE isoforms and further contribute to our understanding of the potential mechanisms influencing cardiomyocyte repolarization.

  18. 14 CFR 29.1163 - Powerplant accessories.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Powerplant accessories. (a) Each engine mounted accessory must— (1) Be approved for mounting on the engine involved; (2) Use the provisions on the engine for mounting; and (3) Be sealed in such a way as to prevent...

  19. 14 CFR 27.1163 - Powerplant accessories.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Powerplant accessories. (a) Each engine-mounted accessory must— (1) Be approved for mounting on the engine involved; (2) Use the provisions on the engine for mounting; and (3) Be sealed in such a way as to prevent...

  20. Characterization of Atg38 and NRBF2, a fifth subunit of the autophagic Vps34/PIK3C3 complex

    PubMed Central

    Ohashi, Yohei; Soler, Nicolas; García Ortegón, Miguel; Zhang, Lufei; Kirsten, Marie L.; Perisic, Olga; Masson, Glenn R.; Burke, John E.; Jakobi, Arjen J.; Apostolakis, Apostolos A.; Johnson, Christopher M.; Ohashi, Maki; Ktistakis, Nicholas T.; Sachse, Carsten; Williams, Roger L.

    2016-01-01

    ABSTRACT The phosphatidylinositol 3-kinase Vps34 is part of several protein complexes. The structural organization of heterotetrameric complexes is starting to emerge, but little is known about organization of additional accessory subunits that interact with these assemblies. Combining hydrogen-deuterium exchange mass spectrometry (HDX-MS), X-ray crystallography and electron microscopy (EM), we have characterized Atg38 and its human ortholog NRBF2, accessory components of complex I consisting of Vps15-Vps34-Vps30/Atg6-Atg14 (yeast) and PIK3R4/VPS15-PIK3C3/VPS34-BECN1/Beclin 1-ATG14 (human). HDX-MS shows that Atg38 binds the Vps30-Atg14 subcomplex of complex I, using mainly its N-terminal MIT domain and bridges the coiled-coil I regions of Atg14 and Vps30 in the base of complex I. The Atg38 C-terminal domain is important for localization to the phagophore assembly site (PAS) and homodimerization. Our 2.2 Å resolution crystal structure of the Atg38 C-terminal homodimerization domain shows 2 segments of α-helices assembling into a mushroom-like asymmetric homodimer with a 4-helix cap and a parallel coiled-coil stalk. One Atg38 homodimer engages a single complex I. This is in sharp contrast to human NRBF2, which also forms a homodimer, but this homodimer can bridge 2 complex I assemblies. PMID:27630019

  1. Electrophysiology and Beyond: Multiple roles of Na+ channel β subunits in development and disease

    PubMed Central

    Patino, Gustavo A.; Isom, Lori L.

    2010-01-01

    Voltage-gated Na+ channel (VGSC) β subunits are not “auxiliary.” These multifunctional molecules not only modulate Na+ current (INa), but also function as cell adhesion molecules (CAMs) – playing roles in aggregation, migration, invasion, neurite outgrowth, and axonal fasciculation. β subunits are integral members of VGSC signaling complexes at nodes of Ranvier, axon initial segments, and cardiac intercalated disks, regulating action potential propagation through critical intermolecular and cell-cell communication events. At least in vitro, many β subunit cell adhesive functions occur both in the presence and absence of pore-forming VGSC α subunits, and in vivo β subunits are expressed in excitable as well as non-excitable cells, thus β subunits may play important functional roles on their own, in the absence of α subunits. VGSC β1 subunits are essential for life and appear to be especially important during brain development. Mutations in β subunit genes result in a variety of human neurological and cardiovascular diseases. Moreover, some cancer cells exhibit alterations in β subunit expression during metastasis. In short, these proteins, originally thought of as merely accessory to α subunits, are critical players in their own right in human health and disease. Here we discuss the role of VGSC β subunits in the nervous system. PMID:20600605

  2. K(v) channel interacting protein 3 expression and regulation by haloperidol in midbrain dopaminergic neurons.

    PubMed

    Duncan, Carlotta E; Schofield, Peter R; Weickert, Cynthia Shannon

    2009-12-22

    Antipsychotic drugs are the main treatment for schizophrenia, despite their adverse side effects and uncertain mode of action. Gene expression studies in the brains of rodents treated with antipsychotic drugs aim to uncover this mechanism and elucidate more specific targets for schizophrenia treatment. Previous expression profiling analyses showed that K(v) channel interacting protein 3 (KChIP3) was down-regulated in the mouse brain following treatment with multiple antipsychotic drugs. In this study, we used in situ hybridization to anatomically define the expression of KChIP3 mRNA in the mouse brain and to quantify its regulation by 7-day haloperidol treatment. We used immunohistochemistry to localize KChIP3 protein expression in the midbrain, dorsal and ventral striatum and the prefrontal cortex. We found KChIP3 mRNA throughout the grey matter of the brain, with high expression in the hippocampus, specific thalamic nuclei, deeper cortical layers and in the midbrain. KChIP3 mRNA was significantly down-regulated in the dorsal striatum and the ventral tegmental area following haloperidol treatment. KChIP3 protein is expressed in the neuropil in the cortex and striatum, as well as in the soma of deeper layer cortical and striatal neurons. This study, for the first time, also localized KChIP3 protein in the cell bodies and processes of dopaminergic neurons in the midbrain. These findings indicate that regulation of KChIP3, particularly in mesocortical dopamine neurons, may be part of the action of antipsychotic drugs and that prolonged and more specific targeting of ion channel subunits may enhance the therapeutic effects of antipsychotic drugs.

  3. Determination of the Stoichiometry between α- and γ1 Subunits of the BK Channel Using LRET.

    PubMed

    Carrasquel-Ursulaez, Willy; Alvarez, Osvaldo; Bezanilla, Francisco; Latorre, Ramon

    2018-06-05

    Two families of accessory proteins, β and γ, modulate BK channel gating and pharmacology. Notably, in the absence of internal Ca 2+ , the γ1 subunit promotes a large shift of the BK conductance-voltage curve to more negative potentials. However, very little is known about how α- and γ1 subunits interact. In particular, the association stoichiometry between both subunits is unknown. Here, we propose a method to answer this question using lanthanide resonance energy transfer. The method assumes that the kinetics of lanthanide resonance energy transfer-sensitized emission of the donor double-labeled α/γ1 complex is the linear combination of the kinetics of the sensitized emission in single-labeled complexes. We used a lanthanide binding tag engineered either into the α- or the γ1 subunits to bind Tb +3 as the donor. The acceptor (BODIPY) was attached to the BK pore-blocker iberiotoxin. We determined that γ1 associates with the α-subunit with a maximal 1:1 stoichiometry. This method could be applied to determine the stoichiometry of association between proteins within heteromultimeric complexes. Copyright © 2018 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  4. The Laser Accessory Market

    NASA Astrophysics Data System (ADS)

    Desai, Ashvin

    1988-09-01

    Wandering through the exhibit hall yesterday, I noticed that if you look at the laser companies and if you look at the accessory companies, there are pretty much the same number of accessory booths as well as the laser companies. There was one difference. Laser company booths are all sexy looking, very flashy, big booths. Whereas if you look at the accessories booths, they were small, not so prominent.

  5. 14 CFR 23.1163 - Powerplant accessories.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... section, be sealed to prevent contamination of the engine oil system and the accessory system. (b... engine is hazardous when malfunctioning occurs, a means to prevent rotation without interfering with the... Controls and Accessories § 23.1163 Powerplant accessories. (a) Each engine mounted accessory must— (1) Be...

  6. 14 CFR 23.1163 - Powerplant accessories.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... section, be sealed to prevent contamination of the engine oil system and the accessory system. (b... engine is hazardous when malfunctioning occurs, a means to prevent rotation without interfering with the... Controls and Accessories § 23.1163 Powerplant accessories. (a) Each engine mounted accessory must— (1) Be...

  7. 14 CFR 23.1163 - Powerplant accessories.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... section, be sealed to prevent contamination of the engine oil system and the accessory system. (b... engine is hazardous when malfunctioning occurs, a means to prevent rotation without interfering with the... Controls and Accessories § 23.1163 Powerplant accessories. (a) Each engine mounted accessory must— (1) Be...

  8. 14 CFR 23.1163 - Powerplant accessories.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... section, be sealed to prevent contamination of the engine oil system and the accessory system. (b... engine is hazardous when malfunctioning occurs, a means to prevent rotation without interfering with the... Controls and Accessories § 23.1163 Powerplant accessories. (a) Each engine mounted accessory must— (1) Be...

  9. Immunohistochemical localization of DPP10 in rat brain supports the existence of a Kv4/KChIP/DPPL ternary complex in neurons.

    PubMed

    Wang, Wan-Chen; Cheng, Chau-Fu; Tsaur, Meei-Ling

    2015-03-01

    Subthreshold A-type K(+) currents (ISA s) have been recorded from the cell bodies of hippocampal and neocortical interneurons as well as neocortical pyramidal neurons. Kv4 channels are responsible for the somatodendritic ISA s. It has been proposed that neuronal Kv4 channels are ternary complexes including pore-forming Kv4 subunits, K(+) channel-interacting proteins (KChIPs), and dipeptidyl peptidase-like proteins (DPPLs). However, colocalization evidence was still lacking. The distribution of DPP10 mRNA in rodent brain has been reported but its protein localization remains unknown. In this study, we generated a DPP10 antibody to label DPP10 protein in adult rat brain by immunohistochemistry. Absent from glia, DPP10 proteins appear mainly in the cell bodies of DPP10(+) neurons, not only at the plasma membrane but also in the cytoplasm. At least 6.4% of inhibitory interneurons in the hippocampus coexpressed Kv4.3, KChIP1, and DPP10, with the highest density in the CA1 strata alveus/oriens/pyramidale and the dentate hilus. Colocalization of Kv4.3/KChIP1/DPP10 was also detected in at least 6.9% of inhibitory interneurons scattered throughout the neocortex. Both hippocampal and neocortical Kv4.3/KChIP1/DPP10(+) inhibitory interneurons expressed parvalbumin or somatostatin, but not calbindin or calretinin. Furthermore, we found colocalization of Kv4.2/Kv4.3/KChIP3/DPP10 in neocortical layer 5 pyramidal neurons and olfactory bulb mitral cells. Together, although DPP10 is also expressed in some brain neurons lacking Kv4 (such as parvalbumin- and somatostatin-positive Golgi cells in the cerebellum), colocalization of DPP10 with Kv4 and KChIP at the plasma membrane of ISA -expressing neuron somata supports the existence of Kv4/KChIP/DPPL ternary complex in vivo. © 2014 Wiley Periodicals, Inc.

  10. Subcomplexes of Ancestral Respiratory Complex I Subunits Rapidly Turn Over in Vivo as Productive Assembly Intermediates in Arabidopsis*

    PubMed Central

    Li, Lei; Nelson, Clark J.; Carrie, Chris; Gawryluk, Ryan M. R.; Solheim, Cory; Gray, Michael W.; Whelan, James; Millar, A. Harvey

    2013-01-01

    Subcomplexes of mitochondrial respiratory complex I (CI; EC 1.6.5.3) are shown to turn over in vivo, and we propose a role in an ancestral assembly pathway. By progressively labeling Arabidopsis cell cultures with 15N and isolating mitochondria, we have identified CI subcomplexes through differences in 15N incorporation into their protein subunits. The 200-kDa subcomplex, containing the ancestral γ-carbonic anhydrase (γ-CA), γ-carbonic anhydrase-like, and 20.9-kDa subunits, had a significantly higher turnover rate than intact CI or CI+CIII2. In vitro import of precursors for these CI subunits demonstrated rapid generation of subcomplexes and revealed that their specific abundance varied when different ancestral subunits were imported. Time course studies of precursor import showed the further assembly of these subcomplexes into CI and CI+CIII2, indicating that the subcomplexes are productive intermediates of assembly. The strong transient incorporation of new subunits into the 200-kDa subcomplex in a γ-CA mutant is consistent with this subcomplex being a key initiator of CI assembly in plants. This evidence alongside the pattern of coincident occurrence of genes encoding these particular proteins broadly in eukaryotes, except for opisthokonts, provides a framework for the evolutionary conservation of these accessory subunits and evidence of their function in ancestral CI assembly. PMID:23271729

  11. Voltage-gated sodium channel β subunits: The power outside the pore in brain development and disease.

    PubMed

    Hull, Jacob M; Isom, Lori L

    2018-04-01

    Voltage gated sodium channels (VGSCs) were first identified in terms of their role in the upstroke of the action potential. The underlying proteins were later identified as saxitoxin and scorpion toxin receptors consisting of α and β subunits. We now know that VGSCs are heterotrimeric complexes consisting of a single pore forming α subunit joined by two β subunits; a noncovalently linked β1 or β3 and a covalently linked β2 or β4 subunit. VGSC α subunits contain all the machinery necessary for channel cell surface expression, ion conduction, voltage sensing, gating, and inactivation, in one central, polytopic, transmembrane protein. VGSC β subunits are more than simple accessories to α subunits. In the more than two decades since the original cloning of β1, our knowledge of their roles in physiology and pathophysiology has expanded immensely. VGSC β subunits are multifunctional. They confer unique gating mechanisms, regulate cellular excitability, affect brain development, confer distinct channel pharmacology, and have functions that are independent of the α subunits. The vast array of functions of these proteins stems from their special station in the channelome: being the only known constituents that are cell adhesion and intra/extracellular signaling molecules in addition to being part of channel complexes. This functional trifecta and how it goes awry demonstrates the power outside the pore in ion channel signaling complexes, broadening the term channelopathy beyond defects in ion conduction. This article is part of the Special Issue entitled 'Channelopathies.' Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Live-cell imaging reveals the dynamics of PRC2 and recruitment to chromatin by SUZ12-associated subunits.

    PubMed

    Youmans, Daniel T; Schmidt, Jens C; Cech, Thomas R

    2018-06-01

    Polycomb-repressive complex 2 (PRC2) is a histone methyltransferase that promotes epigenetic gene silencing, but the dynamics of its interactions with chromatin are largely unknown. Here we quantitatively measured the binding of PRC2 to chromatin in human cancer cells. Genome editing of a HaloTag into the endogenous EZH2 and SUZ12 loci and single-particle tracking revealed that ∼80% of PRC2 rapidly diffuses through the nucleus, while ∼20% is chromatin-bound. Short-term treatment with a small molecule inhibitor of the EED-H3K27me3 interaction had no immediate effect on the chromatin residence time of PRC2. In contrast, separation-of-function mutants of SUZ12, which still form the core PRC2 complex but cannot bind accessory proteins, revealed a major contribution of AEBP2 and PCL homolog proteins to chromatin binding. We therefore quantified the dynamics of this chromatin-modifying complex in living cells and separated the contributions of H3K27me3 histone marks and various PRC2 subunits to recruitment of PRC2 to chromatin. © 2018 Youmans et al.; Published by Cold Spring Harbor Laboratory Press.

  13. Tetrameric subunit structure of the native brain inwardly rectifying potassium channel Kir 2.2.

    PubMed

    Raab-Graham, K F; Vandenberg, C A

    1998-07-31

    Strongly inwardly rectifying potassium channels of the Kir 2 subfamily (IRK1, IRK2, and IRK3) are involved in maintenance and modulation of cell excitability in brain and heart. Electrophysiological studies of channels expressed in heterologous systems have suggested that the pore-conducting pathway contains four subunits. However, inferences from electrophysiological studies have not been tested on native channels and do not address the possibility of nonconducting auxiliary subunits. Here, we investigate the subunit stoichiometry of endogenous inwardly rectifying potassium channel Kir 2.2 (IRK2) from rat brain. Using chemical cross-linking, immunoprecipitiation, and velocity sedimentation, we report physical evidence demonstrating the tetrameric organization of the native channel. Kir 2.2 was sequentially cross-linked to produce bands on SDS-polyacrylamide gel electrophoresis corresponding in size to monomer, dimer, trimer, and three forms of tetramer. Fully cross-linked channel was present as a single band of tetrameric size. Immunoprecipitation of biotinylated membranes revealed a single band corresponding to Kir 2.2, suggesting that the channel is composed of a single type of subunit. Hydrodynamic properties of 3-[(3-cholamidopropyl)dimethylammonio]-1-propane sulfonic acid-solubilized channel were used to calculate the molecular mass of the channel. Velocity sedimentation in H2O or D2O gave a sharp peak with a sedimentation coefficient of 17.3 S. Gel filtration yielded a Stokes radius of 5.92 nm. These data indicate a multisubunit protein with a molecular mass of 193 kDa, calculated to contain 3.98 subunits. Together, these results demonstrate that Kir 2.2 channels are formed by the homotetrameric association of Kir 2.2 subunits and do not contain tightly associated auxiliary subunits. These studies suggest that Kir 2.2 channels differ in structure from related heterooctomeric ATP-sensitive K channels and heterotetrameric G-protein-regulated inward rectifier K

  14. Loss of GluN2D subunit results in social recognition deficit, social stress, 5-HT2C receptor dysfunction, and anhedonia in mice.

    PubMed

    Yamamoto, Hideko; Kamegaya, Etsuko; Hagino, Yoko; Takamatsu, Yukio; Sawada, Wakako; Matsuzawa, Maaya; Ide, Soichiro; Yamamoto, Toshifumi; Mishina, Masayoshi; Ikeda, Kazutaka

    2017-01-01

    The N-methyl-d-aspartate (NMDA) receptor channel is involved in various physiological functions, including learning and memory. The GluN2D subunit of the NMDA receptor has low expression in the mature brain, and its role is not fully understood. In the present study, the effects of GluN2D subunit deficiency on emotional and cognitive function were investigated in GluN2D knockout (KO) mice. We found a reduction of motility (i.e., a depressive-like state) in the tail suspension test and a reduction of sucrose preference (i.e., an anhedonic state) in GluN2D KO mice that were group-housed with littermates. Despite apparently normal olfactory function and social interaction, GluN2D KO mice exhibited a decrease in preference for social novelty, suggesting a deficit in social recognition or memory. Golgi-Cox staining revealed a reduction of the complexity of dendritic trees in the accessory olfactory bulb in GluN2D KO mice, suggesting a deficit in pheromone processing pathway activation, which modulates social recognition. The deficit in social recognition may result in social stress in GluN2D KO mice. Isolation housing is a procedure that has been shown to reduce stress in mice. Interestingly, 3-week isolation and treatment with agomelatine or the 5-hydroxytryptamine-2C (5-HT 2C ) receptor antagonist SB242084 reversed the anhedonic-like state in GluN2D KO mice. In contrast, treatment with the 5-HT 2C receptor agonist CP809101 induced depressive- and anhedonic-like states in isolated GluN2D KO mice. These results suggest that social stress that is caused by a deficit in social recognition desensitizes 5-HT 2c receptors, followed by an anhedonic- and depressive-like state, in GluN2D KO mice. The GluN2D subunit of the NMDA receptor appears to be important for the recognition of individuals and development of normal emotionality in mice. 5-HT 2C receptor antagonism may be a therapeutic target for treating social stress-induced anhedonia. This article is part of the Special

  15. The first transmembrane domain (TM1) of β2-subunit binds to the transmembrane domain S1 of α-subunit in BK potassium channels

    PubMed Central

    Morera, Francisco J.; Alioua, Abderrahmane; Kundu, Pallob; Salazar, Marcelo; Gonzalez, Carlos; Martinez, Agustin D.; Stefani, Enrico; Toro, Ligia; Latorre, Ramon

    2012-01-01

    The BK channel is one of the most broadly expressed ion channels in mammals. In many tissues, the BK channel pore-forming α-subunit is associated to an auxiliary β-subunit that modulates the voltage- and Ca2+-dependent activation of the channel. Structural components present in β-subunits that are important for the physical association with the α-subunit are yet unknown. Here, we show through co-immunoprecipitation that the intracellular C-terminus, the second transmembrane domain (TM2) and the extracellular loop of the β2-subunit are dispensable for association with the α-subunit pointing transmembrane domain 1 (TM1) as responsible for the interaction. Indeed, the TOXCAT assay for transmembrane protein–protein interactions demonstrated for the first time that TM1 of the β2-subunit physically binds to the transmembrane S1 domain of the α-subunit. PMID:22710124

  16. 21 CFR 876.4890 - Urological table and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ..., stirrups, and belts used to support a patient in a suitable position for endoscopic procedures of the lower...) Class II (special controls) for the electrically powered urological table and accessories. The device is... § 876.9. (2) Class I for the manually powered table and accessories, and for stirrups for electrically...

  17. 14 CFR 25.1163 - Powerplant accessories.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... the engine oil system and the accessory system. (b) Electrical equipment subject to arcing or sparking... to prevent rotation without interfering with the continued operation of the engine. [Doc. No. 5066... Powerplant accessories. (a) Each engine mounted accessory must— (1) Be approved for mounting on the engine...

  18. 14 CFR 25.1163 - Powerplant accessories.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... the engine oil system and the accessory system. (b) Electrical equipment subject to arcing or sparking... to prevent rotation without interfering with the continued operation of the engine. [Doc. No. 5066... Powerplant accessories. (a) Each engine mounted accessory must— (1) Be approved for mounting on the engine...

  19. 14 CFR 25.1163 - Powerplant accessories.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... the engine oil system and the accessory system. (b) Electrical equipment subject to arcing or sparking... to prevent rotation without interfering with the continued operation of the engine. [Doc. No. 5066... Powerplant accessories. (a) Each engine mounted accessory must— (1) Be approved for mounting on the engine...

  20. 14 CFR 25.1163 - Powerplant accessories.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... the engine oil system and the accessory system. (b) Electrical equipment subject to arcing or sparking... to prevent rotation without interfering with the continued operation of the engine. [Doc. No. 5066... Powerplant accessories. (a) Each engine mounted accessory must— (1) Be approved for mounting on the engine...

  1. DPP10 splice variants are localized in distinct neuronal populations and act to differentially regulate the inactivation properties of Kv4-based ion channels.

    PubMed

    Jerng, Henry H; Lauver, Aaron D; Pfaffinger, Paul J

    2007-08-01

    Dipeptidyl peptidase-like proteins (DPLs) and Kv-channel-interacting proteins (KChIPs) join Kv4 pore-forming subunits to form multi-protein complexes that underlie subthreshold A-type currents (I(SA)) in neuronal somatodendritic compartments. Here, we characterize the functional effects and brain distributions of N-terminal variants belonging to the DPL dipeptidyl peptidase 10 (DPP10). In the Kv4.2+KChIP3+DPP10 channel complex, all DPP10 variants accelerate channel gating kinetics; however, the splice variant DPP10a produces uniquely fast inactivation kinetics that accelerates with increasing depolarization. This DPP10a-specific inactivation dominates in co-expression studies with KChIP4a and other DPP10 isoforms. Real-time qRT-PCR and in situ hybridization analyses reveal differential expression of DPP10 variants in rat brain. DPP10a transcripts are prominently expressed in the cortex, whereas DPP10c and DPP10d mRNAs exhibit more diffuse distributions. Our results suggest that DPP10a underlies rapid inactivation of cortical I(SA), and the regulation of isoform expression may contribute to the variable inactivation properties of I(SA) across different brain regions.

  2. Cloning and characterization of two novel zebrafish P2X receptor subunits.

    PubMed

    Diaz-Hernandez, Miguel; Cox, Jane A; Migita, Keisuke; Haines, William; Egan, Terrance M; Voigt, Mark M

    2002-07-26

    In this report we describe the cloning and characterization of two P2X receptor subunits cloned from the zebrafish (Danio rerio). Primary sequence analysis suggests that one cDNA encodes an ortholog of the mammalian P2X(4) subunit and the second cDNA encodes the ortholog of the mammalian P2X(5) subunit. The zP2X(4) subunit forms a homo-oligomeric receptor that displays a low affinity for ATP (EC(50)=274+/-48 microM) and very low affinity (EC(50)>500 microM) for other purinergic ligands such as alphabetameATP, suramin, and PPADS. As seen with the mammalian orthologs, the zP2X(5) subunit forms a homo-oligomeric receptor that yields very small whole-cell currents (<20pA), making determination of an EC(50) problematic. Both subunit genes were physically mapped onto the zebrafish genome using radiation hybrid analysis of the T51 panel, with the zp2x4 localized to LG21 and zp2x5 to LG5.

  3. 21 CFR 878.4960 - Operating tables and accessories and operating chairs and accessories.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Operating tables and accessories and operating chairs and accessories. 878.4960 Section 878.4960 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical...

  4. 21 CFR 878.4960 - Operating tables and accessories and operating chairs and accessories.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Operating tables and accessories and operating chairs and accessories. 878.4960 Section 878.4960 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical...

  5. 21 CFR 878.4960 - Operating tables and accessories and operating chairs and accessories.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Operating tables and accessories and operating chairs and accessories. 878.4960 Section 878.4960 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical...

  6. 21 CFR 878.4960 - Operating tables and accessories and operating chairs and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Operating tables and accessories and operating chairs and accessories. 878.4960 Section 878.4960 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical...

  7. 21 CFR 878.4960 - Operating tables and accessories and operating chairs and accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Operating tables and accessories and operating chairs and accessories. 878.4960 Section 878.4960 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical...

  8. Inhibition of Human Cytomegalovirus DNA Polymerase by C-Terminal Peptides from the UL54 Subunit

    PubMed Central

    Loregian, Arianna; Rigatti, Roberto; Murphy, Mary; Schievano, Elisabetta; Palu, Giorgio; Marsden, Howard S.

    2003-01-01

    In common with other herpesviruses, the human cytomegalovirus (HCMV) DNA polymerase contains a catalytic subunit (Pol or UL54) and an accessory protein (UL44) that is thought to increase the processivity of the enzyme. The observation that antisense inhibition of UL44 synthesis in HCMV-infected cells strongly inhibits viral DNA replication, together with the structural similarity predicted for the herpesvirus processivity subunits, highlights the importance of the accessory protein for virus growth and raises the possibility that the UL54/UL44 interaction might be a valid target for antiviral drugs. To investigate this possibility, overlapping peptides spanning residues 1161 to 1242 of UL54 were synthesized and tested for inhibition of the interaction between purified UL54 and UL44 proteins. A peptide, LPRRLHLEPAFLPYSVKAHECC, corresponding to residues 1221 to 1242 at the very C terminus of UL54, disrupted both the physical interaction between the two proteins and specifically inhibited the stimulation of UL54 by UL44. A mutant peptide lacking the two carboxy-terminal cysteines was markedly less inhibitory, suggesting a role for these residues in the UL54/UL44 interaction. Circular dichroism spectroscopy indicated that the UL54 C-terminal peptide can adopt a partially α-helical structure. Taken together, these results indicate that the two subunits of HCMV DNA polymerase most likely interact in a way which is analogous to that of the two subunits of herpes simplex virus DNA polymerase, even though there is no sequence homology in the binding site, and suggest that the UL54 peptide, or derivatives thereof, could form the basis for developing a new class of anti-HCMV inhibitors that act by disrupting the UL54/UL44 interaction. PMID:12857903

  9. Structural basis of subunit selectivity for competitive NMDA receptor antagonists with preference for GluN2A over GluN2B subunits

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lind, Genevieve E.; Mou, Tung-Chung; Tamborini, Lucia

    NMDA-type glutamate receptors are ligand-gated ion channels that contribute to excitatory neurotransmission in the central nervous system (CNS). Most NMDA receptors comprise two glycine-binding GluN1 and two glutamate-binding GluN2 subunits (GluN2A–D). We describe highly potent (S)-5-[(R)-2-amino-2-carboxyethyl]-4,5-dihydro-1H-pyrazole-3-carboxylic acid (ACEPC) competitive GluN2 antagonists, of which ST3 has a binding affinity of 52 nM at GluN1/2A and 782 nM at GluN1/2B receptors. This 15-fold preference of ST3 for GluN1/2A over GluN1/2B is improved compared with NVP-AAM077, a widely used GluN2A-selective antagonist, which we show has 11-fold preference for GluN1/2A over GluN1/2B. Crystal structures of the GluN1/2A agonist binding domain (ABD) heterodimer with boundmore » ACEPC antagonists reveal a binding mode in which the ligands occupy a cavity that extends toward the subunit interface between GluN1 and GluN2A ABDs. Mutational analyses show that the GluN2A preference of ST3 is primarily mediated by four nonconserved residues that are not directly contacting the ligand, but positioned within 12 Å of the glutamate binding site. Two of these residues influence the cavity occupied by ST3 in a manner that results in favorable binding to GluN2A, but occludes binding to GluN2B. Thus, we reveal opportunities for the design of subunit-selective competitive NMDA receptor antagonists by identifying a cavity for ligand binding in which variations exist between GluN2A and GluN2B subunits. This structural insight suggests that subunit selectivity of glutamate-site antagonists can be mediated by mechanisms in addition to direct contributions of contact residues to binding affinity.« less

  10. Structural basis of subunit selectivity for competitive NMDA receptor antagonists with preference for GluN2A over GluN2B subunits

    PubMed Central

    Lind, Genevieve E.; Mou, Tung-Chung; Tamborini, Lucia; Pomper, Martin G.; De Micheli, Carlo; Conti, Paola; Pinto, Andrea

    2017-01-01

    NMDA-type glutamate receptors are ligand-gated ion channels that contribute to excitatory neurotransmission in the central nervous system (CNS). Most NMDA receptors comprise two glycine-binding GluN1 and two glutamate-binding GluN2 subunits (GluN2A–D). We describe highly potent (S)-5-[(R)-2-amino-2-carboxyethyl]-4,5-dihydro-1H-pyrazole-3-carboxylic acid (ACEPC) competitive GluN2 antagonists, of which ST3 has a binding affinity of 52 nM at GluN1/2A and 782 nM at GluN1/2B receptors. This 15-fold preference of ST3 for GluN1/2A over GluN1/2B is improved compared with NVP-AAM077, a widely used GluN2A-selective antagonist, which we show has 11-fold preference for GluN1/2A over GluN1/2B. Crystal structures of the GluN1/2A agonist binding domain (ABD) heterodimer with bound ACEPC antagonists reveal a binding mode in which the ligands occupy a cavity that extends toward the subunit interface between GluN1 and GluN2A ABDs. Mutational analyses show that the GluN2A preference of ST3 is primarily mediated by four nonconserved residues that are not directly contacting the ligand, but positioned within 12 Å of the glutamate binding site. Two of these residues influence the cavity occupied by ST3 in a manner that results in favorable binding to GluN2A, but occludes binding to GluN2B. Thus, we reveal opportunities for the design of subunit-selective competitive NMDA receptor antagonists by identifying a cavity for ligand binding in which variations exist between GluN2A and GluN2B subunits. This structural insight suggests that subunit selectivity of glutamate-site antagonists can be mediated by mechanisms in addition to direct contributions of contact residues to binding affinity. PMID:28760974

  11. [Excision of accessory navicular with reconstruction of posterior tibial tendon insertion on navicular for treatment of flatfoot related with accessory navicular].

    PubMed

    Cao, Honghui; Tang, Kanglai; Deng, Yinshuan; Tan, Xiaokang; Zhou, Binghua; Tao, Xu; Chen, Lei; Chen, Qianbo

    2012-06-01

    To analyze the excision of accessory navicular with reconstruction of posterior tibial tendon insertion on navicular for the treatment of flatfoot related with accessory navicular and to evaluate its effectiveness. Between May 2006 and June 2011, 33 patients (40 feet) with flatfoot related with accessory navicular were treated. There were 14 males (17 feet) and 19 females (23 feet) with an average age of 30.1 years (range, 16-56 years). All patients had bilateral accessory navicular; 26 had unilateral flatfoot and 7 had bilateral flatfeet. The disease duration ranged from 7 months to 9 years (median, 24 months). The American Orthopaedic Foot and Ankle Society (AOFAS) ankle-midfoot score was 47.9 +/- 7.3. The X-ray films showed type II accessory navicular, the arch height loss, and heel valgus in all patients. All of them received excision of accessory navicular and reconstruction of posterior tibial tendon insertion on navicular with anchor. All patients got primary wound healing without any complication. Thirty patients (36 feet) were followed up 6-54 months with an average of 23 months. All patients achieved complete pain relief at 6 months after surgery and had good appearance of the feet. The AOFAS ankle-midfoot score was 90.4 +/- 2.0 at last follow-up, showing significant difference when compared with preoperative score (t=29.73, P=0.00). X-ray films showed that no screw loosening or breakage was observed. There were significant differences in the arch height, calcaneus inclination angle, talocalcaneal angle, and talar-first metatarsal angle between pre-operation and last follow-up (P < 0.01). The excision of accessory navicular with reconstruction of posterior tibial tendon insertion on navicular is a good choice for the treatment of flatfoot related with accessory navicular, with correction of deformity, excellent effectiveness, and less complications.

  12. Catalytic Subunit 1 of Protein Phosphatase 2A Is a Subunit of the STRIPAK Complex and Governs Fungal Sexual Development.

    PubMed

    Beier, Anna; Teichert, Ines; Krisp, Christoph; Wolters, Dirk A; Kück, Ulrich

    2016-06-21

    The generation of complex three-dimensional structures is a key developmental step for most eukaryotic organisms. The details of the molecular machinery controlling this step remain to be determined. An excellent model system to study this general process is the generation of three-dimensional fruiting bodies in filamentous fungi like Sordaria macrospora Fruiting body development is controlled by subunits of the highly conserved striatin-interacting phosphatase and kinase (STRIPAK) complex, which has been described in organisms ranging from yeasts to humans. The highly conserved heterotrimeric protein phosphatase PP2A is a subunit of STRIPAK. Here, catalytic subunit 1 of PP2A was functionally characterized. The Δpp2Ac1 strain is sterile, unable to undergo hyphal fusion, and devoid of ascogonial septation. Further, PP2Ac1, together with STRIPAK subunit PRO22, governs vegetative and stress-related growth. We revealed in vitro catalytic activity of wild-type PP2Ac1, and our in vivo analysis showed that inactive PP2Ac1 blocks the complementation of the sterile deletion strain. Tandem affinity purification, followed by mass spectrometry and yeast two-hybrid analysis, verified that PP2Ac1 is a subunit of STRIPAK. Further, these data indicate links between the STRIPAK complex and other developmental signaling pathways, implying the presence of a large interconnected signaling network that controls eukaryotic developmental processes. The insights gained in our study can be transferred to higher eukaryotes and will be important for understanding eukaryotic cellular development in general. The striatin-interacting phosphatase and kinase (STRIPAK) complex is highly conserved from yeasts to humans and is an important regulator of numerous eukaryotic developmental processes, such as cellular signaling and cell development. Although functional insights into the STRIPAK complex are accumulating, the detailed molecular mechanisms of single subunits are only partially understood

  13. Highly conserved small subunit residues influence rubisco large subunit catalysis.

    PubMed

    Genkov, Todor; Spreitzer, Robert J

    2009-10-30

    The chloroplast enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) catalyzes the rate-limiting step of photosynthetic CO(2) fixation. With a deeper understanding of its structure-function relationships and competitive inhibition by O(2), it may be possible to engineer an increase in agricultural productivity and renewable energy. The chloroplast-encoded large subunits form the active site, but the nuclear-encoded small subunits can also influence catalytic efficiency and CO(2)/O(2) specificity. To further define the role of the small subunit in Rubisco function, the 10 most conserved residues in all small subunits were substituted with alanine by transformation of a Chlamydomonas reinhardtii mutant that lacks the small subunit gene family. All the mutant strains were able to grow photosynthetically, indicating that none of the residues is essential for function. Three of the substitutions have little or no effect (S16A, P19A, and E92A), one primarily affects holoenzyme stability (L18A), and the remainder affect catalysis with or without some level of associated structural instability (Y32A, E43A, W73A, L78A, P79A, and F81A). Y32A and E43A cause decreases in CO(2)/O(2) specificity. Based on the x-ray crystal structure of Chlamydomonas Rubisco, all but one (Glu-92) of the conserved residues are in contact with large subunits and cluster near the amino- or carboxyl-terminal ends of large subunit alpha-helix 8, which is a structural element of the alpha/beta-barrel active site. Small subunit residues Glu-43 and Trp-73 identify a possible structural connection between active site alpha-helix 8 and the highly variable small subunit loop between beta-strands A and B, which can also influence Rubisco CO(2)/O(2) specificity.

  14. The Kv7.2/Kv7.3 heterotetramer assembles with a random subunit arrangement.

    PubMed

    Stewart, Andrew P; Gómez-Posada, Juan Camilo; McGeorge, Jessica; Rouhani, Maral J; Villarroel, Alvaro; Murrell-Lagnado, Ruth D; Edwardson, J Michael

    2012-04-06

    Voltage-gated K(+) channels composed of Kv7.2 and Kv7.3 are the predominant contributors to the M-current, which plays a key role in controlling neuronal activity. Various lines of evidence have indicated that Kv7.2 and Kv7.3 form a heteromeric channel. However, the subunit stoichiometry and arrangement within this putative heteromer are so far unknown. Here, we have addressed this question using atomic force microscopy imaging of complexes between isolated Kv7.2/Kv7.3 channels and antibodies to epitope tags on the two subunits, Myc on Kv7.2 and HA on Kv7.3. Initially, tsA 201 cells were transiently transfected with equal amounts of cDNA for the two subunits. The heteromer was isolated through binding of either tag to immunoaffinity beads and then decorated with antibodies to the other tag. In both cases, the distribution of angles between pairs of bound antibodies had two peaks, at around 90° and around 180°, and in both cases the 90° peak was about double the size of the 180° peak. These results indicate that the Kv7.2/Kv7.3 heteromer generated by cells expressing approximately equal amounts of the two subunits assembles as a tetramer with a predominantly 2:2 subunit stoichiometry and with a random subunit arrangement. When the DNA ratio for the two subunits was varied, copurification experiments indicated that the subunit stoichiometry was variable and not fixed at 2:2. Hence, there are no constraints on either the subunit stoichiometry or the subunit arrangement.

  15. Accessory Muscles of the Extremities.

    PubMed

    Vanhoenacker, Filip M; Desimpel, Julie; Mespreuve, Marc; Tagliafico, Alberto

    2018-07-01

    Accessory muscles and variations are not uncommon at the upper and lower extremity. They are often overlooked because they are asymptomatic and present as incidental findings on imaging. However, they may present as a soft tissue swelling, thereby mimicking soft tissue tumors. Other symptoms are attributed to impingement on neurovascular structures and to exercise-related pain. Thorough knowledge of the anatomy, systematic imaging analysis, and the awareness of it are the clues to correct identification. On ultrasound, accessory muscles have a similar echotexture as other muscles, whereas the signal intensity on magnetic resonance imaging (MRI) is similar to muscle. Because of the intrinsic contrast with the adjacent intermuscular fat, accessory muscles are best depicted on MRI without fat suppression. This article provides a short overview of the anatomy of most prevalent accessory muscles of the upper and lower limb and its potential pathogenic nature. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  16. 21 CFR 878.4350 - Cryosurgical unit and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... and accessories. (a) Identification—(1) Cryosurgical unit with a liquid nitrogen cooled cryoprobe and accessories. A cryosurgical unit with a liquid nitrogen cooled cryoprobe and accessories is a device intended...

  17. Structure-function of proteins interacting with the α1 pore-forming subunit of high-voltage-activated calcium channels

    PubMed Central

    Neely, Alan; Hidalgo, Patricia

    2014-01-01

    Openings of high-voltage-activated (HVA) calcium channels lead to a transient increase in calcium concentration that in turn activate a plethora of cellular functions, including muscle contraction, secretion and gene transcription. To coordinate all these responses calcium channels form supramolecular assemblies containing effectors and regulatory proteins that couple calcium influx to the downstream signal cascades and to feedback elements. According to the original biochemical characterization of skeletal muscle Dihydropyridine receptors, HVA calcium channels are multi-subunit protein complexes consisting of a pore-forming subunit (α1) associated with four additional polypeptide chains β, α2, δ, and γ, often referred to as accessory subunits. Twenty-five years after the first purification of a high-voltage calcium channel, the concept of a flexible stoichiometry to expand the repertoire of mechanisms that regulate calcium channel influx has emerged. Several other proteins have been identified that associate directly with the α1-subunit, including calmodulin and multiple members of the small and large GTPase family. Some of these proteins only interact with a subset of α1-subunits and during specific stages of biogenesis. More strikingly, most of the α1-subunit interacting proteins, such as the β-subunit and small GTPases, regulate both gating and trafficking through a variety of mechanisms. Modulation of channel activity covers almost all biophysical properties of the channel. Likewise, regulation of the number of channels in the plasma membrane is performed by altering the release of the α1-subunit from the endoplasmic reticulum, by reducing its degradation or enhancing its recycling back to the cell surface. In this review, we discuss the structural basis, interplay and functional role of selected proteins that interact with the central pore-forming subunit of HVA calcium channels. PMID:24917826

  18. 21 CFR 878.4950 - Manual operating table and accessories and manual operating chair and accessories.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Manual operating table and accessories and manual operating chair and accessories. 878.4950 Section 878.4950 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES...

  19. 21 CFR 878.4950 - Manual operating table and accessories and manual operating chair and accessories.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Manual operating table and accessories and manual operating chair and accessories. 878.4950 Section 878.4950 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES...

  20. 21 CFR 878.4950 - Manual operating table and accessories and manual operating chair and accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Manual operating table and accessories and manual operating chair and accessories. 878.4950 Section 878.4950 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES...

  1. 21 CFR 878.4950 - Manual operating table and accessories and manual operating chair and accessories.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Manual operating table and accessories and manual operating chair and accessories. 878.4950 Section 878.4950 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES...

  2. 21 CFR 878.4950 - Manual operating table and accessories and manual operating chair and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Manual operating table and accessories and manual operating chair and accessories. 878.4950 Section 878.4950 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES...

  3. Glycosylation of β2 Subunits Regulates GABAA Receptor Biogenesis and Channel Gating*

    PubMed Central

    Lo, Wen-yi; Lagrange, Andre H.; Hernandez, Ciria C.; Harrison, Rebecca; Dell, Anne; Haslam, Stuart M.; Sheehan, Jonathan H.; Macdonald, Robert L.

    2010-01-01

    γ-Aminobutyric acid type A (GABAA) receptors are heteropentameric glycoproteins. Based on consensus sequences, the GABAA receptor β2 subunit contains three potential N-linked glycosylation sites, Asn-32, Asn-104, and Asn-173. Homology modeling indicates that Asn-32 and Asn-104 are located before the α1 helix and in loop L3, respectively, near the top of the subunit-subunit interface on the minus side, and that Asn-173 is located in the Cys-loop near the bottom of the subunit N-terminal domain. Using site-directed mutagenesis, we demonstrated that all predicted β2 subunit glycosylation sites were glycosylated in transfected HEK293T cells. Glycosylation of each site, however, produced specific changes in α1β2 receptor surface expression and function. Although glycosylation of Asn-173 in the Cys-loop was important for stability of β2 subunits when expressed alone, results obtained with flow cytometry, brefeldin A treatment, and endo-β-N-acetylglucosaminidase H digestion suggested that glycosylation of Asn-104 was required for efficient α1β2 receptor assembly and/or stability in the endoplasmic reticulum. Patch clamp recording revealed that mutation of each site to prevent glycosylation decreased peak α1β2 receptor current amplitudes and altered the gating properties of α1β2 receptor channels by reducing mean open time due to a reduction in the proportion of long open states. In addition to functional heterogeneity, endo-β-N-acetylglucosaminidase H digestion and glycomic profiling revealed that surface β2 subunit N-glycans at Asn-173 were high mannose forms that were different from those of Asn-32 and N104. Using a homology model of the pentameric extracellular domain of α1β2 channel, we propose mechanisms for regulation of GABAA receptors by glycosylation. PMID:20639197

  4. COP9 signalosome subunit 7 from Arabidopsis interacts with and regulates the small subunit of ribonucleotide reductase (RNR2).

    PubMed

    Halimi, Yair; Dessau, Moshe; Pollak, Shaul; Ast, Tslil; Erez, Tamir; Livnat-Levanon, Nurit; Karniol, Baruch; Hirsch, Joel A; Chamovitz, Daniel A

    2011-09-01

    The COP9 Signalosome protein complex (CSN) is a pleiotropic regulator of plant development and contains eight-subunits. Six of these subunits contain the PCI motif which mediates specific protein interactions necessary for the integrity of the complex. COP9 complex subunit 7 (CSN7) contains an N-terminal PCI motif followed by a C-terminal extension which is also necessary for CSN function. A yeast-interaction trap assay identified the small subunit of ribonucelotide reductase (RNR2) from Arabidopsis as interacting with the C-terminal section of CSN7. This interaction was confirmed in planta by both bimolecular fluorescence complementation and immuoprecipitation assays with endogenous proteins. The subcellular localization of RNR2 was primarily nuclear in meristematic regions, and cytoplasmic in adult cells. RNR2 was constitutively nuclear in csn7 mutant seedlings, and was also primarily nuclear in wild type seedlings following exposure to UV-C. These two results correlate with constitutive expression of several DNA-damage response genes in csn7 mutants, and to increased tolerance of csn7 seedlings to UV-C treatment. We propose that the CSN is a negative regulator of RNR activity in Arabidopsis.

  5. Overexpressing wild-type γ2 subunits rescued the seizure phenotype in Gabrg2+/Q390X Dravet syndrome mice.

    PubMed

    Huang, Xuan; Zhou, Chengwen; Tian, Mengnan; Kang, Jing-Qiong; Shen, Wangzhen; Verdier, Kelienne; Pimenta, Aurea; MacDonald, Robert L

    2017-08-01

    The mutant γ-aminobutyric acid type A (GABA A ) receptor γ2(Q390X) subunit (Q351X in the mature peptide) has been associated with the epileptic encephalopathy, Dravet syndrome, and the epilepsy syndrome genetic epilepsy with febrile seizures plus (GEFS+). The mutation generates a premature stop codon that results in translation of a stable truncated and misfolded γ2 subunit that accumulates in neurons, forms intracellular aggregates, disrupts incorporation of γ2 subunits into GABA A receptors, and affects trafficking of partnering α and β subunits. Heterozygous Gabrg2 +/Q390X knock-in (KI) mice had reduced cortical inhibition, spike wave discharges on electroencephalography (EEG), a lower seizure threshold to the convulsant drug pentylenetetrazol (PTZ), and spontaneous generalized tonic-clonic seizures. In this proof-of-principal study, we attempted to rescue these deficits in KI mice using a γ2 subunit gene (GABRG2) replacement therapy. We introduced the GABRG2 allele by crossing Gabrg2 +/Q390X KI mice with bacterial artificial chromosome (BAC) transgenic mice overexpressing HA (hemagglutinin)-tagged human γ2 HA subunits, and compared GABA A receptor subunit expression by Western blot and immunohistochemical staining, seizure threshold by monitoring mouse behavior after PTZ-injection, and thalamocortical inhibition and network oscillation by slice recording. Compared to KI mice, adult mice carrying both mutant allele and transgene had increased wild-type γ2 and partnering α1 and β2/3 subunits, increased miniature inhibitory postsynaptic current (mIPSC) amplitudes recorded from layer VI cortical neurons, reduced thalamocortical network oscillations, and higher PTZ seizure threshold. Based on these results we suggest that seizures in a genetic epilepsy syndrome caused by epilepsy mutant γ2(Q390X) subunits with dominant negative effects could be rescued potentially by overexpression of wild-type γ2 subunits. Wiley Periodicals, Inc. © 2017 International

  6. The NMDA receptor NR2A subunit regulates proliferation of MKN45 human gastric cancer cells

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Watanabe, Kanako; Department of Anesthesiology, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya 663-8501; Kanno, Takeshi

    2008-03-07

    The present study investigated proliferation of MKN28 and MKN45 human gastric cancer cells regulated by the N-methyl-D-aspartate (NMDA) receptor subunit. The NMDA receptor antagonist DL-2-amino-5-phosphonovaleric acid (AP5) inhibited proliferation of MKN45 cells, but not MKN28 cells. Of the NMDA subunits such as NR1, NR2 (2A, 2B, 2C, and 2D), and NR3 (3A and 3B), all the NMDA subunit mRNAs except for the NR2B subunit mRNA were expressed in both MKN28 and MKN45 cells. MKN45 cells were characterized by higher expression of the NR2A subunit mRNA and lower expression of the NR1 subunit mRNA, but MKN28 otherwise by higher expression ofmore » the NR1 subunit mRNA and lower expression of the NR2A subunit mRNA. MKN45 cell proliferation was also inhibited by silencing the NR2A subunit-targeted gene. For MKN45 cells, AP5 or knocking-down the NR2A subunit increased the proportion of cells in the G{sub 1} phase of cell cycling and decreased the proportion in the S/G{sub 2} phase. The results of the present study, thus, suggest that blockage of NMDA receptors including the NR2A subunit suppresses MKN45 cell proliferation due to cell cycle arrest at the G{sub 1} phase; in other words, the NR2A subunit promotes MKN45 cell proliferation by accelerating cell cycling.« less

  7. Complete Spinal Accessory Nerve Palsy From Carrying Climbing Gear.

    PubMed

    Coulter, Jess M; Warme, Winston J

    2015-09-01

    We report an unusual case of spinal accessory nerve palsy sustained while transporting climbing gear. Spinal accessory nerve injury is commonly a result of iatrogenic surgical trauma during lymph node excision. This particular nerve is less frequently injured by blunt trauma. The case reported here results from compression of the spinal accessory nerve for a sustained period-that is, carrying a load over the shoulder using a single nylon rope for 2.5 hours. This highlights the importance of using proper load-carrying equipment to distribute weight over a greater surface area to avoid nerve compression in the posterior triangle of the neck. The signs and symptoms of spinal accessory nerve palsy and its etiology are discussed. This report is particularly relevant to individuals involved in mountaineering and rock climbing but can be extended to anyone carrying a load with a strap over one shoulder and across the body. Copyright © 2015 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

  8. 21 CFR 884.6120 - Assisted reproduction accessories.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... II (special controls) (design specifications, labeling requirements, and clinical testing). ... Assisted reproduction accessories. (a) Identification. Assisted reproduction accessories are a group of...

  9. 21 CFR 884.6120 - Assisted reproduction accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... II (special controls) (design specifications, labeling requirements, and clinical testing). ... Assisted reproduction accessories. (a) Identification. Assisted reproduction accessories are a group of...

  10. 21 CFR 884.6120 - Assisted reproduction accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... II (special controls) (design specifications, labeling requirements, and clinical testing). ... Assisted reproduction accessories. (a) Identification. Assisted reproduction accessories are a group of...

  11. β-Subunits Promote the Expression of CaV2.2 Channels by Reducing Their Proteasomal Degradation*

    PubMed Central

    Waithe, Dominic; Ferron, Laurent; Page, Karen M.; Chaggar, Kanchan; Dolphin, Annette C.

    2011-01-01

    The β-subunits of voltage-gated calcium channels regulate their functional expression and properties. Two mechanisms have been proposed for this, an effect on gating and an enhancement of expression. With respect to the effect on expression, β-subunits have been suggested to enhance trafficking by masking an unidentified endoplasmic reticulum (ER) retention signal. Here we have investigated whether, and how, β-subunits affect the level of CaV2.2 channels within somata and neurites of cultured sympathetic neurons. We have used YFP-CaV2.2 containing a mutation (W391A), that prevents binding of β-subunits to its I-II linker and found that expression of this channel was much reduced compared with WT CFP-CaV2.2 when both were expressed in the same neuron. This effect was particularly evident in neurites and growth cones. The difference between the levels of YFP-CaV2.2(W391A) and CFP-CaV2.2(WT) was lost in the absence of co-expressed β-subunits. Furthermore, the relative reduction of expression of CaV2.2(W391A) compared with the WT channel was reversed by exposure to two proteasome inhibitors, MG132 and lactacystin, particularly in the somata. In further experiments in tsA-201 cells, we found that proteasome inhibition did not augment the cell surface CaV2.2(W391A) level but resulted in the observation of increased ubiquitination, particularly of mutant channels. In contrast, we found no evidence for selective retention of CaV2.2(W391A) in the ER, in either the soma or growth cones. In conclusion, there is a marked effect of β-subunits on CaV2.2 expression, particularly in neurites, but our results point to protection from proteasomal degradation rather than masking of an ER retention signal. PMID:21233207

  12. 21 CFR 872.3980 - Endosseous dental implant accessories.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Endosseous dental implant accessories. 872.3980... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3980 Endosseous dental implant accessories. (a) Identification. Endosseous dental implant accessories are manually powered devices intended...

  13. 21 CFR 872.3980 - Endosseous dental implant accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Endosseous dental implant accessories. 872.3980... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3980 Endosseous dental implant accessories. (a) Identification. Endosseous dental implant accessories are manually powered devices intended...

  14. 21 CFR 872.3980 - Endosseous dental implant accessories.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Endosseous dental implant accessories. 872.3980... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3980 Endosseous dental implant accessories. (a) Identification. Endosseous dental implant accessories are manually powered devices intended...

  15. 21 CFR 872.3980 - Endosseous dental implant accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Endosseous dental implant accessories. 872.3980... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3980 Endosseous dental implant accessories. (a) Identification. Endosseous dental implant accessories are manually powered devices intended...

  16. 21 CFR 872.3980 - Endosseous dental implant accessories.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Endosseous dental implant accessories. 872.3980... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3980 Endosseous dental implant accessories. (a) Identification. Endosseous dental implant accessories are manually powered devices intended...

  17. A novel DPP6 isoform (DPP6-E) can account for differences between neuronal and reconstituted A-type K(+) channels.

    PubMed

    Maffie, Jonathon; Blenkinsop, Timothy; Rudy, Bernardo

    2009-01-16

    The channels mediating most of the somatodendritic A-type K(+) current in neurons are thought to be ternary complexes of Kv4 pore-forming subunits and two types of auxiliary subunits, the K(+) channel interacting proteins (KChIPs) and dipeptidyl-peptidase-like (DPPL) proteins. The channels expressed in heterologous expression systems by mixtures of Kv4.2, KChIP1 and DPP6-S resemble in many properties the A-type current in hippocampal CA1 pyramidal neurons and cerebellar granule cells, neurons with prominent A-type K(+) currents. However, the native currents have faster kinetics. Moreover, the A-type currents in neurons in intermediary layers of the superior colliculus have even faster inactivating rates. We have characterized a new DPP6 spliced isoform, DPP6-E, that produces in heterologous cells ternary Kv4 channels with very fast kinetics. DPP6-E is selectively expressed in a few neuronal populations in brain including cerebellar granule neurons, hippocampal pyramidal cells and neurons in intermediary layers of the superior colliculus. The effects of DPP6-E explain past discrepancies between reconstituted and native Kv4 channels in some neurons, and contributes to the diversity of A-type K(+) currents in neurons.

  18. 21 CFR 876.5250 - Urine collector and accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Urine collector and accessories. 876.5250 Section... (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5250 Urine collector and accessories. (a) Identification. A urine collector and accessories is a device intended to collect...

  19. 21 CFR 876.5250 - Urine collector and accessories.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Urine collector and accessories. 876.5250 Section... (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5250 Urine collector and accessories. (a) Identification. A urine collector and accessories is a device intended to collect...

  20. 21 CFR 876.5250 - Urine collector and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Urine collector and accessories. 876.5250 Section... (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5250 Urine collector and accessories. (a) Identification. A urine collector and accessories is a device intended to collect...

  1. 21 CFR 876.5250 - Urine collector and accessories.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Urine collector and accessories. 876.5250 Section... (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5250 Urine collector and accessories. (a) Identification. A urine collector and accessories is a device intended to collect...

  2. 21 CFR 876.5250 - Urine collector and accessories.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Urine collector and accessories. 876.5250 Section... (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5250 Urine collector and accessories. (a) Identification. A urine collector and accessories is a device intended to collect...

  3. 21 CFR 868.5860 - Pressure tubing and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pressure tubing and accessories. 868.5860 Section... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5860 Pressure tubing and accessories. (a) Identification. Pressure tubing and accessories are flexible or rigid devices intended to...

  4. Visual and auditory accessory stimulus offset and the Simon effect.

    PubMed

    Nishimura, Akio; Yokosawa, Kazuhiko

    2010-10-01

    We investigated the effect on the right and left responses of the disappearance of a task-irrelevant stimulus located on the right or left side. Participants pressed a right or left response key on the basis of the color of a centrally located visual target. Visual (Experiment 1) or auditory (Experiment 2) task-irrelevant accessory stimuli appeared or disappeared at locations to the right or left of the central target. In Experiment 1, responses were faster when onset or offset of the visual accessory stimulus was spatially congruent with the response. In Experiment 2, responses were again faster when onset of the auditory accessory stimulus and the response were on the same side. However, responses were slightly slower when offset of the auditory accessory stimulus and the response were on the same side than when they were on opposite sides. These findings indicate that transient change information is crucial for a visual Simon effect, whereas sustained stimulation from an ongoing stimulus also contributes to an auditory Simon effect.

  5. Three Accessories for a Rotating Platform.

    ERIC Educational Resources Information Center

    Riley, James A.; Fryer, Oscar G.

    1980-01-01

    Describes three accessories developed to be used in conjunction with the rotating platform or turntable. Three demonstrations using these accessories are included. These demonstrations are: (a) conservation of angular momentum; (b) gravity-defying goblets; and (c) direct measurement of centripetal force. (HM)

  6. 14 CFR 25.1192 - Engine accessory section diaphragm.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Engine accessory section diaphragm. 25.1192....1192 Engine accessory section diaphragm. For reciprocating engines, the engine power section and all portions of the exhaust system must be isolated from the engine accessory compartment by a diaphragm that...

  7. 14 CFR 25.1192 - Engine accessory section diaphragm.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Engine accessory section diaphragm. 25.1192....1192 Engine accessory section diaphragm. For reciprocating engines, the engine power section and all portions of the exhaust system must be isolated from the engine accessory compartment by a diaphragm that...

  8. 14 CFR 25.1192 - Engine accessory section diaphragm.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Engine accessory section diaphragm. 25.1192....1192 Engine accessory section diaphragm. For reciprocating engines, the engine power section and all portions of the exhaust system must be isolated from the engine accessory compartment by a diaphragm that...

  9. 21 CFR 872.4200 - Dental handpiece and accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Dental handpiece and accessories. 872.4200 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4200 Dental handpiece and accessories. (a) Identification. A dental handpiece and accessories is an AC-powered, water-powered, air-powered, or belt-driven...

  10. 21 CFR 872.4200 - Dental handpiece and accessories.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Dental handpiece and accessories. 872.4200 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4200 Dental handpiece and accessories. (a) Identification. A dental handpiece and accessories is an AC-powered, water-powered, air-powered, or belt-driven...

  11. 21 CFR 872.4200 - Dental handpiece and accessories.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Dental handpiece and accessories. 872.4200 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4200 Dental handpiece and accessories. (a) Identification. A dental handpiece and accessories is an AC-powered, water-powered, air-powered, or belt-driven...

  12. 21 CFR 872.4200 - Dental handpiece and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Dental handpiece and accessories. 872.4200 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4200 Dental handpiece and accessories. (a) Identification. A dental handpiece and accessories is an AC-powered, water-powered, air-powered, or belt-driven...

  13. 21 CFR 872.4200 - Dental handpiece and accessories.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Dental handpiece and accessories. 872.4200 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4200 Dental handpiece and accessories. (a) Identification. A dental handpiece and accessories is an AC-powered, water-powered, air-powered, or belt-driven...

  14. 21 CFR 876.5900 - Ostomy pouch and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ostomy pouch and accessories. 876.5900 Section 876...) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5900 Ostomy pouch and accessories. (a) Identification. An ostomy pouch and accessories is a device that consists of a bag that is...

  15. 21 CFR 872.6250 - Dental chair and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Dental chair and accessories. 872.6250 Section 872...) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6250 Dental chair and accessories. (a) Identification. A dental chair and accessories is a device, usually AC-powered, in which a patient sits. The...

  16. 21 CFR 872.6250 - Dental chair and accessories.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Dental chair and accessories. 872.6250 Section 872...) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6250 Dental chair and accessories. (a) Identification. A dental chair and accessories is a device, usually AC-powered, in which a patient sits. The...

  17. 21 CFR 872.6250 - Dental chair and accessories.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Dental chair and accessories. 872.6250 Section 872...) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6250 Dental chair and accessories. (a) Identification. A dental chair and accessories is a device, usually AC-powered, in which a patient sits. The...

  18. 21 CFR 872.6250 - Dental chair and accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Dental chair and accessories. 872.6250 Section 872...) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6250 Dental chair and accessories. (a) Identification. A dental chair and accessories is a device, usually AC-powered, in which a patient sits. The...

  19. 21 CFR 872.6250 - Dental chair and accessories.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Dental chair and accessories. 872.6250 Section 872...) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6250 Dental chair and accessories. (a) Identification. A dental chair and accessories is a device, usually AC-powered, in which a patient sits. The...

  20. Accessories make the outfit: Accessory Chromosomes and other dispensable DNA regions in plant-pathogenic Fungi.

    PubMed

    Bertazzoni, Stefania; Williams, Angela; Jones, Darcy A B; Syme, Robert A; Tan, Kar-Chun; Hane, James Kyawzwar

    2018-04-17

    Fungal pathogen genomes can often be divided into core and accessory regions. Accessory regions may be comprised of either accessory regions (ARs) within core chromosomes (CCs), or wholly-dispensable (accessory) chromosomes (ACs). Fungal ACs and ARs typically accumulate mutations and structural rearrangements more rapidly over time than CCs, and many harbour genes relevant to host-pathogen interactions. These regions are of particular interest in plant pathology and include host-specific virulence factors and secondary metabolite synthesis gene clusters. This review outlines known ACs and ARs in fungal genomes, methods used for their detection, their common properties that differentiate them from the core genome, and what is currently known of their various roles in pathogenicity. Reports on the evolutionary processes generating and shaping AC/AR compartments are discussed, including repeat induced point mutation (RIP) and breakage-fusion-bridge (BFB) cycles. Previously ACs have been studied extensively within key genera including Fusarium, Zymoseptoria and Alternaria, but are growing in their frequency of observation and perceived importance across a wider range of fungal species. Recent advances in sequencing technologies permit affordable genome assembly and re-sequencing of populations that will facilitate further discovery and routine screening of ACs.

  1. The Crystal Structure of PF-8, the DNA Polymerase Accessory Subunit from Kaposi's Sarcoma-Associated Herpesvirus

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Baltz, Jennifer L.; Filman, David J.; Ciustea, Mihai

    2009-12-01

    Kaposi's sarcoma-associated herpesvirus is an emerging pathogen whose mechanism of replication is poorly understood. PF-8, the presumed processivity factor of Kaposi's sarcoma-associated herpesvirus DNA polymerase, acts in combination with the catalytic subunit, Pol-8, to synthesize viral DNA. We have solved the crystal structure of residues 1 to 304 of PF-8 at a resolution of 2.8 {angstrom}. This structure reveals that each monomer of PF-8 shares a fold common to processivity factors. Like human cytomegalovirus UL44, PF-8 forms a head-to-head dimer in the form of a C clamp, with its concave face containing a number of basic residues that are predictedmore » to be important for DNA binding. However, there are several differences with related proteins, especially in loops that extend from each monomer into the center of the C clamp and in the loops that connect the two subdomains of each protein, which may be important for determining PF-8's mode of binding to DNA and to Pol-8. Using the crystal structures of PF-8, the herpes simplex virus catalytic subunit, and RB69 bacteriophage DNA polymerase in complex with DNA and initial experiments testing the effects of inhibition of PF-8-stimulated DNA synthesis by peptides derived from Pol-8, we suggest a model for how PF-8 might form a ternary complex with Pol-8 and DNA. The structure and the model suggest interesting similarities and differences in how PF-8 functions relative to structurally similar proteins.« less

  2. 21 CFR 890.5925 - Traction accessory.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Traction accessory. 890.5925 Section 890.5925 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5925 Traction accessory. (a...

  3. 21 CFR 890.5925 - Traction accessory.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Traction accessory. 890.5925 Section 890.5925 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5925 Traction accessory. (a...

  4. 21 CFR 890.5925 - Traction accessory.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Traction accessory. 890.5925 Section 890.5925 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5925 Traction accessory. (a...

  5. 21 CFR 890.5925 - Traction accessory.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Traction accessory. 890.5925 Section 890.5925 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5925 Traction accessory. (a...

  6. 21 CFR 890.5925 - Traction accessory.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Traction accessory. 890.5925 Section 890.5925 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5925 Traction accessory. (a...

  7. 47 CFR 15.27 - Special accessories.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... information required by this section may be included in the manual in that alternative form, provided the user..., shall ensure that these special accessories are provided with the equipment. The instruction manual for... responsibility of the user to use the needed special accessories supplied with the equipment. In cases where the...

  8. Future Development of Endoscopic Accessories for Endoscopic Submucosal Dissection

    PubMed Central

    Jang, Jae-Young

    2017-01-01

    Endoscopic submucosal dissection (ESD) has recently been accepted as a standard treatment for patients with early gastric cancer (EGC), without lymph node metastases. Given the rise in the number of ESDs being performed, new endoscopic accessories are being developed and existing accessories modified to facilitate the execution of ESD and reduce complication rates. This paper examines the history underlying the development of these new endoscopic accessories and indicates future directions for the development of these accessories. PMID:28609819

  9. Subunit rotation of ATP synthase embedded in membranes: a or β subunit rotation relative to the c subunit ring

    PubMed Central

    Nishio, Kazuaki; Iwamoto-Kihara, Atsuko; Yamamoto, Akitsugu; Wada, Yoh; Futai, Masamitsu

    2002-01-01

    ATP synthase FoF1 (α3β3γδɛab2c10–14) couples an electrochemical proton gradient and a chemical reaction through the rotation of its subunit assembly. In this study, we engineered FoF1 to examine the rotation of the catalytic F1 β or membrane sector Fo a subunit when the Fo c subunit ring was immobilized; a biotin-tag was introduced onto the β or a subunit, and a His-tag onto the c subunit ring. Membrane fragments were obtained from Escherichia coli cells carrying the recombinant plasmid for the engineered FoF1 and were immobilized on a glass surface. An actin filament connected to the β or a subunit rotated counterclockwise on the addition of ATP, and generated essentially the same torque as one connected to the c ring of FoF1 immobilized through a His-tag linked to the α or β subunit. These results established that the γɛc10–14 and α3β3δab2 complexes are mechanical units of the membrane-embedded enzyme involved in rotational catalysis. PMID:12357031

  10. Functional Analysis of AP-2 α and μ2 Subunits

    PubMed Central

    Motley, Alison M.; Berg, Nicola; Taylor, Marcus J.; Sahlender, Daniela A.; Hirst, Jennifer; Owen, David J.

    2006-01-01

    The AP-2 adaptor complex plays a key role in cargo recognition and clathrin-coated vesicle formation at the plasma membrane. To investigate the functions of individual binding sites and domains of the AP-2 complex in vivo, we have stably transfected HeLa cells with wild-type and mutant small interfering RNA–resistant α and μ2 subunits and then used siRNA knockdowns to deplete the endogenous proteins. Mutating the PtdIns(4,5)P2 binding site of α, the phosphorylation site of μ2, or the YXXΦ binding site of μ2 impairs AP-2 function, as assayed by transferrin uptake. In contrast, removing the C-terminal appendage domain of α, or mutating the PtdIns(4,5)P2 binding site of μ2, has no apparent effect. However, adding a C-terminal GFP tag to α renders it completely nonfunctional. These findings demonstrate that there is some functional redundancy in the binding sites of the various AP-2 subunits, because no single mutation totally abolishes function. They also help to explain why GFP-tagged AP-2 never appears to leave the plasma membrane in some live cell imaging studies. Finally, they establish a new model system that can be used both for additional structure-function analyses, and as a way of testing tagged constructs for function in vivo. PMID:17035630

  11. 21 CFR 876.1500 - Endoscope and accessories.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... within this generic type of device include cleaning accessories for endoscopes, photographic accessories for endoscopes, nonpowered anoscopes, binolcular attachments for endoscopes, pocket battery boxes... endoscope, smoke removal tube, rechargeable battery box, pocket battery box, bite block for endoscope, and...

  12. 21 CFR 876.1500 - Endoscope and accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... within this generic type of device include cleaning accessories for endoscopes, photographic accessories for endoscopes, nonpowered anoscopes, binolcular attachments for endoscopes, pocket battery boxes... endoscope, smoke removal tube, rechargeable battery box, pocket battery box, bite block for endoscope, and...

  13. 21 CFR 876.1500 - Endoscope and accessories.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... within this generic type of device include cleaning accessories for endoscopes, photographic accessories for endoscopes, nonpowered anoscopes, binolcular attachments for endoscopes, pocket battery boxes... endoscope, smoke removal tube, rechargeable battery box, pocket battery box, bite block for endoscope, and...

  14. 21 CFR 876.1500 - Endoscope and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... within this generic type of device include cleaning accessories for endoscopes, photographic accessories for endoscopes, nonpowered anoscopes, binolcular attachments for endoscopes, pocket battery boxes... endoscope, smoke removal tube, rechargeable battery box, pocket battery box, bite block for endoscope, and...

  15. 21 CFR 876.1500 - Endoscope and accessories.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... within this generic type of device include cleaning accessories for endoscopes, photographic accessories for endoscopes, nonpowered anoscopes, binolcular attachments for endoscopes, pocket battery boxes... endoscope, smoke removal tube, rechargeable battery box, pocket battery box, bite block for endoscope, and...

  16. 21 CFR 872.4920 - Dental electrosurgical unit and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Dental electrosurgical unit and accessories. 872... SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4920 Dental electrosurgical unit and accessories. (a) Identification. A dental electrosurgical unit and accessories is an AC-powered...

  17. 21 CFR 872.4920 - Dental electrosurgical unit and accessories.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Dental electrosurgical unit and accessories. 872... SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4920 Dental electrosurgical unit and accessories. (a) Identification. A dental electrosurgical unit and accessories is an AC-powered...

  18. 21 CFR 872.4920 - Dental electrosurgical unit and accessories.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Dental electrosurgical unit and accessories. 872... SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4920 Dental electrosurgical unit and accessories. (a) Identification. A dental electrosurgical unit and accessories is an AC-powered...

  19. 21 CFR 872.4920 - Dental electrosurgical unit and accessories.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Dental electrosurgical unit and accessories. 872... SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4920 Dental electrosurgical unit and accessories. (a) Identification. A dental electrosurgical unit and accessories is an AC-powered...

  20. 21 CFR 872.4920 - Dental electrosurgical unit and accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Dental electrosurgical unit and accessories. 872... SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4920 Dental electrosurgical unit and accessories. (a) Identification. A dental electrosurgical unit and accessories is an AC-powered...

  1. 21 CFR 872.4120 - Bone cutting instrument and accessories.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Bone cutting instrument and accessories. 872.4120... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4120 Bone cutting instrument and accessories. (a) Identification. A bone cutting instrument and accessories is a metal device intended for use...

  2. 21 CFR 872.4120 - Bone cutting instrument and accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Bone cutting instrument and accessories. 872.4120... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4120 Bone cutting instrument and accessories. (a) Identification. A bone cutting instrument and accessories is a metal device intended for use...

  3. 21 CFR 872.4120 - Bone cutting instrument and accessories.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Bone cutting instrument and accessories. 872.4120... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4120 Bone cutting instrument and accessories. (a) Identification. A bone cutting instrument and accessories is a metal device intended for use...

  4. 21 CFR 872.4120 - Bone cutting instrument and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Bone cutting instrument and accessories. 872.4120... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4120 Bone cutting instrument and accessories. (a) Identification. A bone cutting instrument and accessories is a metal device intended for use...

  5. 21 CFR 872.4120 - Bone cutting instrument and accessories.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Bone cutting instrument and accessories. 872.4120... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4120 Bone cutting instrument and accessories. (a) Identification. A bone cutting instrument and accessories is a metal device intended for use...

  6. 21 CFR 872.6640 - Dental operative unit and accessories.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Dental operative unit and accessories. 872.6640... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6640 Dental operative unit and accessories. (a) Identification. A dental operative unit and accessories is an AC-powered device that is...

  7. 21 CFR 872.6640 - Dental operative unit and accessories.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Dental operative unit and accessories. 872.6640... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6640 Dental operative unit and accessories. (a) Identification. A dental operative unit and accessories is an AC-powered device that is...

  8. 21 CFR 872.6640 - Dental operative unit and accessories.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Dental operative unit and accessories. 872.6640... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6640 Dental operative unit and accessories. (a) Identification. A dental operative unit and accessories is an AC-powered device that is...

  9. 21 CFR 872.6640 - Dental operative unit and accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Dental operative unit and accessories. 872.6640... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6640 Dental operative unit and accessories. (a) Identification. A dental operative unit and accessories is an AC-powered device that is...

  10. 21 CFR 872.6640 - Dental operative unit and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Dental operative unit and accessories. 872.6640... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6640 Dental operative unit and accessories. (a) Identification. A dental operative unit and accessories is an AC-powered device that is...

  11. 21 CFR 878.3925 - Plastic surgery kit and accessories.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Plastic surgery kit and accessories. 878.3925... (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3925 Plastic surgery kit and accessories. (a) Identification. A plastic surgery kit and accessories is a device intended to...

  12. 21 CFR 878.3925 - Plastic surgery kit and accessories.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Plastic surgery kit and accessories. 878.3925... (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3925 Plastic surgery kit and accessories. (a) Identification. A plastic surgery kit and accessories is a device intended to...

  13. 21 CFR 878.3925 - Plastic surgery kit and accessories.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Plastic surgery kit and accessories. 878.3925... (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3925 Plastic surgery kit and accessories. (a) Identification. A plastic surgery kit and accessories is a device intended to...

  14. 21 CFR 878.3925 - Plastic surgery kit and accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Plastic surgery kit and accessories. 878.3925... (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3925 Plastic surgery kit and accessories. (a) Identification. A plastic surgery kit and accessories is a device intended to...

  15. 21 CFR 878.3925 - Plastic surgery kit and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Plastic surgery kit and accessories. 878.3925... (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3925 Plastic surgery kit and accessories. (a) Identification. A plastic surgery kit and accessories is a device intended to...

  16. Essential arginine in subunit a and aspartate in subunit c of FoF1 ATP synthase: effect of repositioning within helix 4 of subunit a and helix 2 of subunit c.

    PubMed

    Langemeyer, Lars; Engelbrecht, Siegfried

    2007-07-01

    FoF1 ATP synthase couples proton flow through the integral membrane portion Fo (ab2c10) to ATP-synthesis in the extrinsic F1-part ((alphabeta)3gammadeltaepsilon) (Escherichia coli nomenclature and stoichiometry). Coupling occurs by mechanical rotation of subunits c10gammaepsilon relative to (alphabeta)3deltaab2. Two residues were found to be essential for proton flow through ab2c10, namely Arg210 in subunit a (aR210) and Asp61 in subunits c (cD61). Their deletion abolishes proton flow, but "horizontal" repositioning, by anchoring them in adjacent transmembrane helices, restores function. Here, we investigated the effects of "vertical" repositioning aR210, cD61, or both by one helical turn towards the N- or C-termini of their original helices. Other than in the horizontal the vertical displacement changes the positions of the side chains within the depth of the membrane. Mutant aR210A/aN214R appeared to be short-circuited in that it supported proton conduction only through EF1-depleted EFo, but not in EFoEF1, nor ATP-driven proton pumping. Mutant cD61N/cM65D grew on succinate, retained the ability to synthesize ATP and supported passive proton conduction but apparently not ATP hydrolysis-driven proton pumping.

  17. 19 CFR 10.537 - Accessories, spare parts, or tools.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... parts, or tools will be taken into account as originating or non-originating materials, as the case may... 19 Customs Duties 1 2010-04-01 2010-04-01 false Accessories, spare parts, or tools. 10.537 Section... Free Trade Agreement Rules of Origin § 10.537 Accessories, spare parts, or tools. Accessories, spare...

  18. The N-methyl-D-aspartate receptor subunits NR2A and NR2B bind to the SH2 domains of phospholipase C-gamma.

    PubMed

    Gurd, J W; Bissoon, N

    1997-08-01

    The NMDA receptor has recently been found to be phosphorylated on tyrosine. To assess the possible connection between tyrosine phosphorylation of the NMDA receptor and signaling pathways in the postsynaptic cell, we have investigated the relationship between tyrosine phosphorylation and the binding of NMDA receptor subunits to the SH2 domains of phospholipase C-gamma (PLC-gamma). A glutathione S-transferase (GST) fusion protein containing both the N- and the C-proximal SH2 domains of PLC-gamma was bound to glutathione-agarose and reacted with synaptic junctional proteins and glycoproteins. Tyrosine-phosphorylated PSD-GP180, which has been identified as the NR2B subunit of the NMDA receptor, bound to the SH2-agarose beads in a phosphorylation-dependent fashion. Immunoblot analysis with antibodies specific for individual NMDA receptor subunits showed that both NR2A and NR2B subunits bound to the SH2-agarose. No binding occurred to GST-agarose lacking an associated SH2 domain, indicating that binding was specific for the SH2 domains. The binding of receptor subunits increased after the incubation of synaptic junctions with ATP and decreased after treatment of synaptic junctions with exogenous protein tyrosine phosphatase. Immunoprecipitation experiments confirmed that NR2A and NR2B were phosphorylated on tyrosine and further that tyrosine phosphorylation of each of the subunits was increased after incubation with ATP. The results demonstrate that NMDA receptor subunits NR2A and NR2B will bind to the SH2 domains of PLC-gamma and that isolated synaptic junctions contain endogenous protein tyrosine kinase(s) that can phosphorylate both NR2A and NR2B receptor subunits, and suggest that interaction of the tyrosine-phosphorylated NMDA receptor with proteins that contain SH2 domains may serve to link it to signaling pathways in the postsynaptic cell.

  19. 21 CFR 886.1930 - Tonometer and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1930 Tonometer and accessories. (a) Identification. A tonometer and accessories is a manual device intended to measure intraocular pressure by applying a known force on the globe of the eye and measuring the amount of indentation produced (Schiotz...

  20. 21 CFR 864.3600 - Microscopes and accessories.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Microscopes and accessories. 864.3600 Section 864.3600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Pathology Instrumentation and Accessories § 864.3600...

  1. 21 CFR 864.3600 - Microscopes and accessories.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Microscopes and accessories. 864.3600 Section 864.3600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Pathology Instrumentation and Accessories § 864.3600...

  2. 21 CFR 864.3600 - Microscopes and accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Microscopes and accessories. 864.3600 Section 864.3600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Pathology Instrumentation and Accessories § 864.3600...

  3. 21 CFR 864.3600 - Microscopes and accessories.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Microscopes and accessories. 864.3600 Section 864.3600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Pathology Instrumentation and Accessories § 864.3600...

  4. Electronic Position Sensor for Power Operated Accessory

    DOEpatents

    Haag, Ronald H.; Chia, Michael I.

    2005-05-31

    An electronic position sensor for use with a power operated vehicle accessory, such as a power liftgate. The position sensor includes an elongated resistive circuit that is mounted such that it is stationary and extends along the path of a track portion of the power operated accessory. The position sensor further includes a contact nub mounted to a link member that moves within the track portion such that the contact nub is slidingly biased against the elongated circuit. As the link member moves under the force of a motor-driven output gear, the contact nub slides along the surface of the resistive circuit, thereby affecting the overall resistance of the circuit. The position sensor uses the overall resistance to provide an electronic position signal to an ECU, wherein the signal is indicative of the absolute position of the power operated accessory. Accordingly, the electronic position sensor is capable of providing an electronic signal that enables the ECU to track the absolute position of the power operated accessory.

  5. Protein synthesis during acquisition of long-term facilitation is needed for the persistent loss of regulatory subunits of the Aplysia cAMP-dependent protein kinase.

    PubMed Central

    Bergold, P J; Sweatt, J D; Winicov, I; Weiss, K R; Kandel, E R; Schwartz, J H

    1990-01-01

    Depending on the number or the length of exposure, application of serotonin can produce either short-term or long-term presynaptic facilitation of Aplysia sensory-to-motor synapses. The cAMP-dependent protein kinase, a heterodimer of two regulatory and two catalytic subunits, has been shown to become stably activated only during long-term facilitation. Both acquisition of long-term facilitation and persistent activation of the kinase is blocked by anisomycin, an effective, reversible, and specific inhibitor of protein synthesis in Aplysia. We report here that 2-hr exposure of pleural sensory cells to serotonin lowers the concentration of regulatory subunits but does not change the concentration of catalytic subunits, as assayed 24 hr later; 5-min exposure to serotonin has no effect on either type of subunit. Increasing intracellular cAMP with a permeable analog of cAMP together with the phosphodiesterase inhibitor isobutyl methylxanthine also decreased regulatory subunits, suggesting that cAMP is the second messenger mediating serotonin action. Anisomycin blocked the loss of regulatory subunits only when applied with serotonin; application after the 2-hr treatment with serotonin had no effect. In the Aplysia accessory radula contractor muscle, prolonged exposure to serotonin or to the peptide transmitter small cardioactive peptide B, both of which produce large increases in intracellular cAMP, does not decrease regulatory subunits. This mechanism of regulating the cAMP-dependent protein kinase therefore may be specific to the nervous system. We conclude that during long-term facilitation, new protein is synthesized in response to the facilitatory stimulus, which changes the ratio of subunits of the cAMP-dependent protein kinase. This alteration in ratio could persistently activate the kinase and produce the persistent phosphorylation seen in long-term facilitated sensory cells. Images PMID:1692622

  6. The HOOK region of voltage-gated Ca2+ channel β subunits senses and transmits PIP2 signals to the gate.

    PubMed

    Park, Cheon-Gyu; Park, Yongsoo; Suh, Byung-Chang

    2017-02-01

    The β subunit of voltage-gated Ca 2+ (Ca V ) channels plays an important role in regulating gating of the α1 pore-forming subunit and its regulation by phosphatidylinositol 4,5-bisphosphate (PIP 2 ). Subcellular localization of the Ca V β subunit is critical for this effect; N-terminal-dependent membrane targeting of the β subunit slows inactivation and decreases PIP 2 sensitivity. Here, we provide evidence that the HOOK region of the β subunit plays an important role in the regulation of Ca V biophysics. Based on amino acid composition, we broadly divide the HOOK region into three domains: S (polyserine), A (polyacidic), and B (polybasic). We show that a β subunit containing only its A domain in the HOOK region increases inactivation kinetics and channel inhibition by PIP 2 depletion, whereas a β subunit with only a B domain decreases these responses. When both the A and B domains are deleted, or when the entire HOOK region is deleted, the responses are elevated. Using a peptide-to-liposome binding assay and confocal microscopy, we find that the B domain of the HOOK region directly interacts with anionic phospholipids via polybasic and two hydrophobic Phe residues. The β2c-short subunit, which lacks an A domain and contains fewer basic amino acids and no Phe residues in the B domain, neither associates with phospholipids nor affects channel gating dynamically. Together, our data suggest that the flexible HOOK region of the β subunit acts as an important regulator of Ca V channel gating via dynamic electrostatic and hydrophobic interaction with the plasma membrane. © 2017 Park et al.

  7. Glycine Receptors Containing α2 or α3 Subunits Regulate Specific Ethanol-Mediated Behaviors

    PubMed Central

    Blednov, Yuri A.; Benavidez, Jillian M.; Black, Mendy; Leiter, Courtney R.; Osterndorff-Kahanek, Elizabeth

    2015-01-01

    Glycine receptors (GlyRs) are broadly expressed in the central nervous system. Ethanol enhances the function of brain GlyRs, and the GlyRα1 subunit is associated with some of the behavioral actions of ethanol, such as loss of righting reflex. The in vivo role of GlyRα2 and α3 subunits in alcohol responses has not been characterized despite high expression levels in the nucleus accumbens and amygdala, areas that are important for the rewarding properties of drugs of abuse. We used an extensive panel of behavioral tests to examine ethanol actions in mice lacking Glra2 (the gene encoding the glycine receptor alpha 2 subunit) or Glra3 (the gene encoding the glycine receptor alpha 3 subunit). Deletion of Glra2 or Glra3 alters specific ethanol-induced behaviors. Glra2 knockout mice demonstrate reduced ethanol intake and preference in the 24-hour two-bottle choice test and increased initial aversive responses to ethanol and lithium chloride. In contrast, Glra3 knockout mice show increased ethanol intake and preference in the 24-hour intermittent access test and increased development of conditioned taste aversion to ethanol. Mutants and wild-type mice consumed similar amounts of ethanol in the limited access drinking in the dark test. Other ethanol effects, such as anxiolysis, motor incoordination, loss of righting reflex, and acoustic startle response, were not altered in the mutants. The behavioral changes in mice lacking GlyRα2 or α3 subunits were distinct from effects previously observed in mice with knock-in mutations in the α1 subunit. We provide evidence that GlyRα2 and α3 subunits may regulate ethanol consumption and the aversive response to ethanol. PMID:25678534

  8. The 2.3 {angstrom} crystal structure of cholera toxin B subunit pentamer: Choleragenoid

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhang, Rong-Guang; Westbrook, M.L.; Maulik, P.R.

    1996-02-01

    Cholera toxin, a heterohexameric AB{sub 5} enterotoxin released by Vibrio cholera, induces a profuse secretory diarrhea in susceptible hosts. Choleragenoid, the B subunit pentamer of cholera toxin, directs the enzymatic A subunit to its target by binding to GM{sub 1} gangliosides exposed on the luminal surface of intestinal epithelial cells. We have solved the crystal structure of choleragenoid at 2.3 {Angstrom} resolution by combining single isomorphous replacement with non-crystallographic symmetry averaging. The structure of the B subunits, and their pentameric arrangement, closely resembles that reported for the intact holotoxin (choleragen), the heat-labile enterotoxin from E. coli, and for a choleragenoid-GM{submore » 1} pentasaccharide complex. In the absence of the A subunit the central cavity of the B pentamer is a highly solvated channel. The binding of the A subunit or the receptor pentasaccharide to choleragenoid has only a modest effect on the local stereochemistry and does not perceptibly alter the subunit interface.« less

  9. 21 CFR 878.1800 - Speculum and accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Speculum and accessories. 878.1800 Section 878.1800 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Diagnostic Devices § 878.1800 Speculum and accessories...

  10. 21 CFR 878.1800 - Speculum and accessories.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Speculum and accessories. 878.1800 Section 878.1800 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Diagnostic Devices § 878.1800 Speculum and accessories...

  11. 21 CFR 878.1800 - Speculum and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Speculum and accessories. 878.1800 Section 878.1800 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Diagnostic Devices § 878.1800 Speculum and accessories...

  12. 21 CFR 878.1800 - Speculum and accessories.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Speculum and accessories. 878.1800 Section 878.1800 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Diagnostic Devices § 878.1800 Speculum and accessories...

  13. 21 CFR 878.1800 - Speculum and accessories.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Speculum and accessories. 878.1800 Section 878.1800 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Diagnostic Devices § 878.1800 Speculum and accessories...

  14. Clinical outcome of surgical treatment of the symptomatic accessory navicular.

    PubMed

    Kopp, Franz J; Marcus, Randall E

    2004-01-01

    When conservative treatment fails to provide relief for a symptomatic accessory navicular, surgical intervention may be necessary. Numerous studies have been published, reporting the results of the traditional Kidner procedure and alternative surgical techniques, all of which produce mostly satisfactory clinical outcomes. The purpose of this study was to report the clinical results, utilizing the American Orthopaedic Foot and Ankle Society (AOFAS) Midfoot Scale, of surgical management for symptomatic accessory navicular with simple excision and anatomic repair of the tibialis posterior tendon. The authors retrospectively reviewed the results of 13 consecutive patients (14 feet) who underwent surgical treatment for symptomatic accessory navicular. The patients ranged in age from 16 to 64 years (average, 34.1 years; mean, 28.2 years) at the time of surgery. All patients had a type II accessory navicular. The average follow-up of the patients involved in the study was 103.4 months (range, 45-194 months). The AOFAS Midfoot Scale was utilized to determine both preoperative and postoperative clinical status of the 14 feet included in the study. The average preoperative AOFAS score was 48.2 (range, 20-75; mean, 38.8). The average postoperative AOFAS score was 94.5 (range, 83-100; mean, 94.3). At last follow-up, 13 of 14 feet were without any pain, no patients had activity limitations, and only two of 14 feet required shoe insert modification. Postoperatively, no patients had a clinically notable change in their preoperative midfoot longitudinal arch alignment. All of the patients in the study were satisfied with the outcome of their surgery and would undergo the same operation again under similar circumstances. When conservative measures fail to relieve the symptoms of a painful accessory navicular, simple excision of the accessory navicular and anatomic repair of the posterior tibialis tendon is a successful intervention. Overall, the procedure provides reliable pain

  15. The importance of immunohistochemical analyses in evaluating the phenotype of Kv channel knockout mice.

    PubMed

    Menegola, Milena; Clark, Eliana; Trimmer, James S

    2012-06-01

    To gain insights into the phenotype of voltage-gated potassium (Kv)1.1 and Kv4.2 knockout mice, we used immunohistochemistry to analyze the expression of component principal or α subunits and auxiliary subunits of neuronal Kv channels in knockout mouse brains. Genetic ablation of the Kv1.1 α subunit did not result in compensatory changes in the expression levels or subcellular distribution of related ion channel subunits in hippocampal medial perforant path and mossy fiber nerve terminals, where high levels of Kv1.1 are normally expressed. Genetic ablation of the Kv4.2 α subunit did not result in altered neuronal cytoarchitecture of the hippocampus. Although Kv4.2 knockout mice did not exhibit compensatory changes in the expression levels or subcellular distribution of the related Kv4.3 α subunit, we found dramatic decreases in the cellular and subcellular expression of specific Kv channel interacting proteins (KChIPs) that reflected their degree of association and colocalization with Kv4.2 in wild-type mouse and rat brains. These studies highlight the insights that can be gained by performing detailed immunohistochemical analyses of Kv channel knockout mouse brains. Wiley Periodicals, Inc. © 2012 International League Against Epilepsy.

  16. Pea chloroplast DNA encodes homologues of Escherichia coli ribosomal subunit S2 and the beta'-subunit of RNA polymerase.

    PubMed Central

    Cozens, A L; Walker, J E

    1986-01-01

    The nucleotide sequence has been determined of a segment of 4680 bases of the pea chloroplast genome. It adjoins a sequence described elsewhere that encodes subunits of the F0 membrane domain of the ATP-synthase complex. The sequence contains a potential gene encoding a protein which is strongly related to the S2 polypeptide of Escherichia coli ribosomes. It also encodes an incomplete protein which contains segments that are homologous to the beta'-subunit of E. coli RNA polymerase and to yeast RNA polymerases II and III. PMID:3530249

  17. 26 CFR 48.4061(b)-2 - Definition of parts or accessories.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... the primary function of the article is to serve a purpose unrelated to the vehicle as such. For... accessories. (a) In general. The term “parts or accessories” includes (1) any article the primary use of which..., and (3) any article the primary use of which is in connection with such chassis, body, or tractor...

  18. 26 CFR 48.4061(b)-2 - Definition of parts or accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... the primary function of the article is to serve a purpose unrelated to the vehicle as such. For... accessories. (a) In general. The term “parts or accessories” includes (1) any article the primary use of which..., and (3) any article the primary use of which is in connection with such chassis, body, or tractor...

  19. 26 CFR 48.4061(b)-2 - Definition of parts or accessories.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... the primary function of the article is to serve a purpose unrelated to the vehicle as such. For... accessories. (a) In general. The term “parts or accessories” includes (1) any article the primary use of which..., and (3) any article the primary use of which is in connection with such chassis, body, or tractor...

  20. Roles of yeast eIF2α and eIF2β subunits in the binding of the initiator methionyl-tRNA

    PubMed Central

    Naveau, Marie; Lazennec-Schurdevin, Christine; Panvert, Michel; Dubiez, Etienne; Mechulam, Yves; Schmitt, Emmanuelle

    2013-01-01

    Heterotrimeric eukaryotic/archaeal translation initiation factor 2 (e/aIF2) binds initiator methionyl-tRNA and plays a key role in the selection of the start codon on messenger RNA. tRNA binding was extensively studied in the archaeal system. The γ subunit is able to bind tRNA, but the α subunit is required to reach high affinity whereas the β subunit has only a minor role. In Saccharomyces cerevisiae however, the available data suggest an opposite scenario with β having the most important contribution to tRNA-binding affinity. In order to overcome difficulties with purification of the yeast eIF2γ subunit, we designed chimeric eIF2 by assembling yeast α and β subunits to archaeal γ subunit. We show that the β subunit of yeast has indeed an important role, with the eukaryote-specific N- and C-terminal domains being necessary to obtain full tRNA-binding affinity. The α subunit apparently has a modest contribution. However, the positive effect of α on tRNA binding can be progressively increased upon shortening the acidic C-terminal extension. These results, together with small angle X-ray scattering experiments, support the idea that in yeast eIF2, the tRNA molecule is bound by the α subunit in a manner similar to that observed in the archaeal aIF2–GDPNP–tRNA complex. PMID:23193270

  1. On the Mg(2+) binding site of the ε subunit from bacterial F-type ATP synthases.

    PubMed

    Krah, Alexander; Takada, Shoji

    2015-10-01

    F-type ATP synthases, central energy conversion machines of the cell synthesize adenosine triphosphate (ATP) using an electrochemical gradient across the membrane and, reversely, can also hydrolyze ATP to pump ions across the membrane, depending on cellular conditions such as ATP concentration. To prevent wasteful ATP hydrolysis, mammalian and bacterial ATP synthases possess different regulatory mechanisms. In bacteria, a low ATP concentration induces a conformational change in the ε subunit from the down- to up-states, which inhibits ATP hydrolysis. Moreover, the conformational change of the ε subunit depends on Mg(2+) concentration in some bacteria such as Bacillus subtilis, but not in others. This diversity makes the ε subunit a potential target for antibiotics. Here, performing molecular dynamics simulations, we identify the Mg(2+) binding site in the ε subunit from B. subtilis as E59 and E86. The free energy analysis shows that the first-sphere bi-dentate coordination of the Mg(2+) ion by the two glutamates is the most stable state. In comparison, we also clarify the reason for the absence of Mg(2+) dependency in the ε subunit from thermophilic Bacillus PS3, despite the high homology to that from B. subtilis. Sequence alignment suggests that this Mg(2+) binding motif is present in the ε subunits of some pathogenic bacteria. In addition we discuss strategies to stabilize an isolated ε subunit carrying the Mg(2+) binding motif by site directed mutagenesis, which also can be used to crystallize Mg(2+) dependent ε subunits in future. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Controlled Speed Accessory Drive demonstration program

    NASA Technical Reports Server (NTRS)

    Hoehn, F. W.

    1981-01-01

    A Controlled Speed Accessory Drive System was examined in an effort to improve the fuel economy of passenger cars. Concept feasibility and the performance of a typical system during actual road driving conditions were demonstrated. The CSAD system is described as a mechanical device which limits engine accessory speeds, thereby reducing parasitic horsepower losses and improving overall vehicle fuel economy. Fuel consumption data were compiled for fleets of GSA vehicles. Various motor pool locations were selected, each representing different climatic conditions. On the basis of a total accumulated fleet usage of nearly three million miles, an overall fuel economy improvement of 6 percent to 7 percent was demonstrated. Coincident chassis dynamometer tests were accomplished on selected vehicles to establish the effect of different accessory drive systems on exhaust emissions, and to evaluate the magnitude of the mileage benefits which could be derived.

  3. Molecular Basis of the Membrane Interaction of the β2e Subunit of Voltage-Gated Ca2+ Channels

    PubMed Central

    Kim, Dong-Il; Kang, Mooseok; Kim, Sangyeol; Lee, Juhwan; Park, Yongsoo; Chang, Iksoo; Suh, Byung-Chang

    2015-01-01

    The auxiliary β subunit plays an important role in the regulation of voltage-gated calcium (CaV) channels. Recently, it was revealed that β2e associates with the plasma membrane through an electrostatic interaction between N-terminal basic residues and anionic phospholipids. However, a molecular-level understanding of β-subunit membrane recruitment in structural detail has remained elusive. In this study, using a combination of site-directed mutagenesis, liposome-binding assays, and multiscale molecular-dynamics (MD) simulation, we developed a physical model of how the β2e subunit is recruited electrostatically to the plasma membrane. In a fluorescence resonance energy transfer assay with liposomes, binding of the N-terminal peptide (23 residues) to liposome was significantly increased in the presence of phosphatidylserine (PS) and phosphatidylinositol 4,5-bisphosphate (PIP2). A mutagenesis analysis suggested that two basic residues proximal to Met-1, Lys-2 (K2) and Trp-5 (W5), are more important for membrane binding of the β2e subunit than distal residues from the N-terminus. Our MD simulations revealed that a stretched binding mode of the N-terminus to PS is required for stable membrane attachment through polar and nonpolar interactions. This mode obtained from MD simulations is consistent with experimental results showing that K2A, W5A, and K2A/W5A mutants failed to be targeted to the plasma membrane. We also investigated the effects of a mutated β2e subunit on inactivation kinetics and regulation of CaV channels by PIP2. In experiments with voltage-sensing phosphatase (VSP), a double mutation in the N-terminus of β2e (K2A/W5A) increased the PIP2 sensitivity of CaV2.2 and CaV1.3 channels by ∼3-fold compared with wild-type β2e subunit. Together, our results suggest that membrane targeting of the β2e subunit is initiated from the nonspecific electrostatic insertion of N-terminal K2 and W5 residues into the membrane. The PS-β2e interaction observed here

  4. Accessory stimulus modulates executive function during stepping task

    PubMed Central

    Watanabe, Tatsunori; Koyama, Soichiro; Tanabe, Shigeo

    2015-01-01

    When multiple sensory modalities are simultaneously presented, reaction time can be reduced while interference enlarges. The purpose of this research was to examine the effects of task-irrelevant acoustic accessory stimuli simultaneously presented with visual imperative stimuli on executive function during stepping. Executive functions were assessed by analyzing temporal events and errors in the initial weight transfer of the postural responses prior to a step (anticipatory postural adjustment errors). Eleven healthy young adults stepped forward in response to a visual stimulus. We applied a choice reaction time task and the Simon task, which consisted of congruent and incongruent conditions. Accessory stimuli were randomly presented with the visual stimuli. Compared with trials without accessory stimuli, the anticipatory postural adjustment error rates were higher in trials with accessory stimuli in the incongruent condition and the reaction times were shorter in trials with accessory stimuli in all the task conditions. Analyses after division of trials according to whether anticipatory postural adjustment error occurred or not revealed that the reaction times of trials with anticipatory postural adjustment errors were reduced more than those of trials without anticipatory postural adjustment errors in the incongruent condition. These results suggest that accessory stimuli modulate the initial motor programming of stepping by lowering decision threshold and exclusively under spatial incompatibility facilitate automatic response activation. The present findings advance the knowledge of intersensory judgment processes during stepping and may aid in the development of intervention and evaluation tools for individuals at risk of falls. PMID:25925321

  5. Expression of functional receptors by the human γ-aminobutyric acid A γ2 subunit

    PubMed Central

    Martínez-Torres, Ataúlfo; Miledi, Ricardo

    2004-01-01

    γ-Aminobutyric acid A (GABAA) receptors are heteromeric membrane proteins formed mainly by various combinations of α, β, and γ subunits; and it is commonly thought that the γ2 subunit alone does not form functional receptors. In contrast, we found that cDNA encoding the γ2L subunit of the human GABAA receptor, injected alone into Xenopus oocytes, expressed functional GABA receptors whose properties were investigated by using the two-microelectrode voltage-clamp technique. GABA elicited desensitizing membrane currents that recovered after a few minutes' wash. Repetitive applications of GABA induced a “run-up” of GABA currents that nearly doubled the amplitude of the first response. The GABA currents inverted direction at about -30 mV, indicating that they are carried mainly by Cl- ions. The homomeric γ2L receptors were also activated by β-alanine > taurine > glycine, and, like some types of heteromeric GABAA receptors, the γ2L receptors were blocked by bicuculline and were potentiated by pentobarbital and flunitrazepam. These results indicate that the human γ2L subunit is capable of forming fully functional GABA receptors by itself in Xenopus oocytes and suggest that the roles proposed for the various subunits that make up the heteromeric GABAA receptors in situ require further clarification. PMID:14981251

  6. The AMPK β2 subunit is required for energy homeostasis during metabolic stress.

    PubMed

    Dasgupta, Biplab; Ju, Jeong Sun; Sasaki, Yo; Liu, Xiaona; Jung, Su-Ryun; Higashida, Kazuhiko; Lindquist, Diana; Milbrandt, Jeffrey

    2012-07-01

    AMP activated protein kinase (AMPK) plays a key role in the regulatory network responsible for maintaining systemic energy homeostasis during exercise or nutrient deprivation. To understand the function of the regulatory β2 subunit of AMPK in systemic energy metabolism, we characterized β2 subunit-deficient mice. Using these mutant mice, we demonstrated that the β2 subunit plays an important role in regulating glucose, glycogen, and lipid metabolism during metabolic stress. The β2 mutant animals failed to maintain euglycemia and muscle ATP levels during fasting. In addition, β2-deficient animals showed classic symptoms of metabolic syndrome, including hyperglycemia, glucose intolerance, and insulin resistance when maintained on a high-fat diet (HFD), and were unable to maintain muscle ATP levels during exercise. Cell surface-associated glucose transporter levels were reduced in skeletal muscle from β2 mutant animals on an HFD. In addition, they displayed poor exercise performance and impaired muscle glycogen metabolism. These mutant mice had decreased activation of AMPK and deficits in PGC1α-mediated transcription in skeletal muscle. Our results highlight specific roles of AMPK complexes containing the β2 subunit and suggest the potential utility of AMPK isoform-specific pharmacological modulators for treatment of metabolic, cardiac, and neurological disorders.

  7. Protein Interactions and Localization of the Escherichia coli Accessory Protein HypA during Nickel Insertion to [NiFe] Hydrogenase*

    PubMed Central

    Chan Chung, Kim C.; Zamble, Deborah B.

    2011-01-01

    Nickel delivery during maturation of Escherichia coli [NiFe] hydrogenase 3 includes the accessory proteins HypA, HypB, and SlyD. Although the isolated proteins have been characterized, little is known about how they interact with each other and the hydrogenase 3 large subunit, HycE. In this study the complexes of HypA and HycE were investigated after modification with the Strep-tag II. Multiprotein complexes containing HypA, HypB, SlyD, and HycE were observed, consistent with the assembly of a single nickel insertion cluster. An interaction between HypA and HycE did not require the other nickel insertion proteins, but HypB was not found with the large subunit in the absence of HypA. The HypA-HycE complex was not detected in the absence of the HypC or HypD proteins, involved in the preceding iron insertion step, and this interaction is enhanced by nickel brought into the cell by the NikABCDE membrane transporter. Furthermore, without the hydrogenase 1, 2, and 3 large subunits, complexes between HypA, HypB, and SlyD were observed. These results support the hypothesis that HypA acts as a scaffold for assembly of the nickel insertion proteins with the hydrogenase precursor protein after delivery of the iron center. At different stages of the hydrogenase maturation process, HypA was observed at or near the cell membrane by using fluorescence confocal microscopy, as was HycE, suggesting membrane localization of the nickel insertion event. PMID:22016389

  8. Clathrin- and AP-2-binding sites in HIP1 uncover a general assembly role for endocytic accessory proteins.

    PubMed

    Mishra, S K; Agostinelli, N R; Brett, T J; Mizukami, I; Ross, T S; Traub, L M

    2001-12-07

    Clathrin-mediated endocytosis is a major pathway for the internalization of macromolecules into the cytoplasm of eukaryotic cells. The principle coat components, clathrin and the AP-2 adaptor complex, assemble a polyhedral lattice at plasma membrane bud sites with the aid of several endocytic accessory proteins. Here, we show that huntingtin-interacting protein 1 (HIP1), a binding partner of huntingtin, copurifies with brain clathrin-coated vesicles and associates directly with both AP-2 and clathrin. The discrete interaction sequences within HIP1 that facilitate binding are analogous to motifs present in other accessory proteins, including AP180, amphiphysin, and epsin. Bound to a phosphoinositide-containing membrane surface via an epsin N-terminal homology (ENTH) domain, HIP1 associates with AP-2 to provide coincident clathrin-binding sites that together efficiently recruit clathrin to the bilayer. Our data implicate HIP1 in endocytosis, and the similar modular architecture and function of HIP1, epsin, and AP180 suggest a common role in lipid-regulated clathrin lattice biogenesis.

  9. The ω Subunit Governs RNA Polymerase Stability and Transcriptional Specificity in Staphylococcus aureus.

    PubMed

    Weiss, Andy; Moore, Brittney D; Tremblay, Miguel H J; Chaput, Dale; Kremer, Astrid; Shaw, Lindsey N

    2017-01-15

    Staphylococcus aureus is a major human pathogen that causes infection in a wide variety of sites within the human body. Its ability to adapt to the human host and to produce a successful infection requires precise orchestration of gene expression. While DNA-dependent RNA polymerase (RNAP) is generally well characterized, the roles of several small accessory subunits within the complex have yet to be fully explored. This is particularly true for the omega (ω or RpoZ) subunit, which has been extensively studied in Gram-negative bacteria but largely neglected in Gram-positive counterparts. In Escherichia coli, it has been shown that ppGpp binding, and thus control of the stringent response, is facilitated by ω. Interestingly, key residues that facilitate ppGpp binding by ω are not conserved in S. aureus, and consequently, survival under starvation conditions is unaffected by rpoZ deletion. Further to this, ω-lacking strains of S. aureus display structural changes in the RNAP complex, which result from increased degradation and misfolding of the β' subunit, alterations in δ and σ factor abundance, and a general dissociation of RNAP in the absence of ω. Through RNA sequencing analysis we detected a variety of transcriptional changes in the rpoZ-deficient strain, presumably as a response to the negative effects of ω depletion on the transcription machinery. These transcriptional changes translated to an impaired ability of the rpoZ mutant to resist stress and to fully form a biofilm. Collectively, our data underline, for the first time, the importance of ω for RNAP stability, function, and cellular physiology in S. aureus IMPORTANCE: In order for bacteria to adjust to changing environments, such as within the host, the transcriptional process must be tightly controlled. Transcription is carried out by DNA-dependent RNA polymerase (RNAP). In addition to its major subunits2 ββ') a fifth, smaller subunit, ω, is present in all forms of life. Although this

  10. Accessory hepatic vein complicating extra-cardiac total cavopulmonary connection.

    PubMed

    Yoshii, Shinpei; Suzuki, Shoji; Osawa, Hiroshi; Hosaka, Shigeru; Honda, Yoshihiro; Abraham, Samuel J K; Tada, Yusuke; Sugiyama, Hisashi; Tan, Tetsushi; Kadono, Toshie; Hoshiai, Minako; Komai, Takayuki

    2002-04-01

    We encountered unexpected, severe hypoxia after the right heart bypass operation in a patient with isomerism. A 2-year-old girl with polysplenia had a complex cardiac anomaly consisting of a single atrium, single ventricle, pulmonary stenosis, absence of the right superior vena cava, hemiazygos continuation of the left inferior vena cava, and d-malposition of the great arteries. After a total cavopulmonary shunt, we performed an extra-cardiac total cavo-pulmonary connection with a 14 mm tube graft. The postoperative course was complicated by severe hypoxia. Angiography performed 20 days after the operation showed that contrast medium in the conduit poured into the hepatic vein, and through the intrahepatic communications, it passed into a left-sided accessory hepatic vein, which was connected directly to the left side of the aspect of the atrium. As the intrahepatic communication was adequate, we ligated the accessory hepatic vein within the pericardial cavity. The SpO2 returned to normal and no hepatic dysfunction was detected. We conclude that surgeons performing extra-cardiac total cavopulmonary connection need to pay closer attention to the possibility that an accessory hepatic vein might exist.

  11. 14 CFR 23.1437 - Accessories for multiengine airplanes.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Accessories for multiengine airplanes. 23... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Equipment Miscellaneous Equipment § 23.1437 Accessories for multiengine airplanes. For multiengine airplanes...

  12. 14 CFR 23.1437 - Accessories for multiengine airplanes.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Accessories for multiengine airplanes. 23... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Equipment Miscellaneous Equipment § 23.1437 Accessories for multiengine airplanes. For multiengine airplanes...

  13. 14 CFR 23.1437 - Accessories for multiengine airplanes.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Accessories for multiengine airplanes. 23... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Equipment Miscellaneous Equipment § 23.1437 Accessories for multiengine airplanes. For multiengine airplanes...

  14. MERS-CoV Accessory ORFs Play Key Role for Infection and Pathogenesis

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Menachery, Vineet D.; Mitchell, Hugh D.; Cockrell, Adam S.

    ABSTRACT While dispensable for viral replication, coronavirus (CoV) accessory open reading frame (ORF) proteins often play critical roles during infection and pathogenesis. Utilizing a previously generated mutant, we demonstrate that the absence of all four Middle East respiratory syndrome CoV (MERS-CoV) accessory ORFs (deletion of ORF3, -4a, -4b, and -5 [dORF3-5]) has major implications for viral replication and pathogenesis. Importantly, attenuation of the dORF3-5 mutant is primarily driven by dysregulated host responses, including disrupted cell processes, augmented interferon (IFN) pathway activation, and robust inflammation.In vitroreplication attenuation also extends toin vivomodels, allowing use of dORF3-5 as a live attenuated vaccine platform.more » Finally, examination of ORF5 implicates a partial role in modulation of NF-κB-mediated inflammation. Together, the results demonstrate the importance of MERS-CoV accessory ORFs for pathogenesis and highlight them as potential targets for surveillance and therapeutic treatments moving forward. IMPORTANCEThe initial emergence and periodic outbreaks of MERS-CoV highlight a continuing threat posed by zoonotic pathogens to global public health. In these studies, mutant virus generation demonstrates the necessity of accessory ORFs in regard to MERS-CoV infection and pathogenesis. With this in mind, accessory ORF functions can be targeted for both therapeutic and vaccine treatments in response to MERS-CoV and related group 2C coronaviruses. In addition, disruption of accessory ORFs in parallel may offer a rapid response platform to attenuation of future emergent strains based on both SARS- and MERS-CoV accessory ORF mutants.« less

  15. 21 CFR 876.5820 - Hemodialysis system and accessories.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    .... (1) The extracorporeal blood system and accessories consists of tubing, pumps, pressure monitors, air... conditions and that consists of an extracorporeal blood system, a conventional dialyzer, a dialysate delivery system, and accessories. Blood from a patient flows through the tubing of the extracorporeal blood system...

  16. 21 CFR 876.5820 - Hemodialysis system and accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    .... (1) The extracorporeal blood system and accessories consists of tubing, pumps, pressure monitors, air... conditions and that consists of an extracorporeal blood system, a conventional dialyzer, a dialysate delivery system, and accessories. Blood from a patient flows through the tubing of the extracorporeal blood system...

  17. 21 CFR 876.5820 - Hemodialysis system and accessories.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    .... (1) The extracorporeal blood system and accessories consists of tubing, pumps, pressure monitors, air... conditions and that consists of an extracorporeal blood system, a conventional dialyzer, a dialysate delivery system, and accessories. Blood from a patient flows through the tubing of the extracorporeal blood system...

  18. 21 CFR 876.5820 - Hemodialysis system and accessories.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    .... (1) The extracorporeal blood system and accessories consists of tubing, pumps, pressure monitors, air... conditions and that consists of an extracorporeal blood system, a conventional dialyzer, a dialysate delivery system, and accessories. Blood from a patient flows through the tubing of the extracorporeal blood system...

  19. 14 CFR 23.1437 - Accessories for multiengine airplanes.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Accessories for multiengine airplanes. 23.1437 Section 23.1437 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF..., engine-driven accessories essential to safe operation must be distributed among two or more engines so...

  20. 14 CFR 23.1437 - Accessories for multiengine airplanes.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Accessories for multiengine airplanes. 23.1437 Section 23.1437 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF..., engine-driven accessories essential to safe operation must be distributed among two or more engines so...

  1. A left lateral accessory pathway unmasked by rivastigmine.

    PubMed

    Guenancia, Charles; Fichot, Marie; Garnier, Fabien; Montoy, Mathieu; Laurent, Gabriel

    A 75-year-old woman was referred for advice regarding surface electrocardiographic modifications after the initiation of rivastigmine. In our patient, the baseline ECGs appeared perfectly normal. However, the initiation of a cholinesterase inhibitor unmasked a left lateral accessory pathway that had never been diagnosed before. Although cholinesterase inhibitors are known to increase vagal tone, the PR interval was shortened after rivastigmine administration, thus excluding this hypothesis to explain the appearance of the accessory pathway. Therefore, we hypothesized that cholinesterase inhibitors may have increased conduction velocity in the accessory pathway or in the atria. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Accessory Axillary Breast Excision with Liposuction Using Minimal Incision: A Preliminary Report.

    PubMed

    Hwang, Seong Bae; Choi, Byung Seo; Byun, Geon Young; Koo, Bum Hwan; Lee, Sung Ryul

    2017-02-01

    Accessory breasts have received little attention in the surgical fields, although the condition is quite common in the female population, with 2-6% of women suffering from it. Its convexity and cyclic pain make women feel embarrassed and uncomfortable, so patients often desire surgical excision to improve their appearances and to remove the pain. A total of 967 patients who had been treated by an excision of accessory breast tissue with liposuction using minimal incision from September 2013 to Dec 2015 at the Damsoyu Hospital were analyzed for clinical factors retrospectively. All 967 patients were female. There were 514 (53.2%) unmarried patients and 453 (46.8%) married patients. The major clinical manifestation was the problem in the appearance with cyclic pain in both unmarried and married groups (82.7 vs. 87.9%). Three types of accessory breasts were observed: 779 (80.6%) breast tissue only in axillae, 182 (18.8%) breast tissue with accessory nipple, and 6 (0.6%) breast tissue with accessory nipple-areolar complex. The mean operation time was 58 min. All cyclic axillar pain in our cases was resolved after the operation. Postoperative complications developed in 160 patients (16.55%). Among them, seroma after operation was the most common (11.27%). In our study, 95.65% of the patients were satisfied with the cosmetic outcomes. The surgical excision of accessory breasts with liposuction through the minimal incision is a safe and effective method to make women feel comfortable in clinical manifestations and be satisfied with their cosmetic axillar line. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

  3. 21 CFR 884.5350 - Contraceptive diaphragm and accessories.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Contraceptive diaphragm and accessories. 884.5350 Section 884.5350 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Devices § 884.5350 Contraceptive diaphragm and accessories. (a) Identification. A contraceptive diaphragm...

  4. 21 CFR 884.5350 - Contraceptive diaphragm and accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Contraceptive diaphragm and accessories. 884.5350 Section 884.5350 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Devices § 884.5350 Contraceptive diaphragm and accessories. (a) Identification. A contraceptive diaphragm...

  5. 21 CFR 884.5350 - Contraceptive diaphragm and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Contraceptive diaphragm and accessories. 884.5350 Section 884.5350 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Devices § 884.5350 Contraceptive diaphragm and accessories. (a) Identification. A contraceptive diaphragm...

  6. 21 CFR 884.5350 - Contraceptive diaphragm and accessories.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Contraceptive diaphragm and accessories. 884.5350 Section 884.5350 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Devices § 884.5350 Contraceptive diaphragm and accessories. (a) Identification. A contraceptive diaphragm...

  7. 21 CFR 884.5350 - Contraceptive diaphragm and accessories.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Contraceptive diaphragm and accessories. 884.5350 Section 884.5350 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Devices § 884.5350 Contraceptive diaphragm and accessories. (a) Identification. A contraceptive diaphragm...

  8. The challenges of classical swine fever control: modified live and E2 subunit vaccines.

    PubMed

    Huang, Yu-Liang; Deng, Ming-Chung; Wang, Fun-In; Huang, Chin-Cheng; Chang, Chia-Yi

    2014-01-22

    Classical swine fever (CSF) is an economically important, highly contagious disease of swine worldwide. CSF is caused by classical swine fever virus (CSFV), and domestic pigs and wild boars are its only natural hosts. The two main strategies used to control CSF epidemic are systematic prophylactic vaccination and a non-vaccination stamping-out policy. This review compares the protective efficacy of the routinely used modified live vaccine (MLV) and E2 subunit vaccines and summarizes the factors that influence the efficacy of the vaccines and the challenges that both vaccines face to CSF control. Although MLV provide earlier and more complete protection than E2 subunit vaccines, it has the drawback of not allowing differentiation between infected and vaccinated animals (DIVA). The marker vaccine of E2 protein with companion discriminatory test to detect antibodies against E(rns) allows DIVA and is a promising strategy for future control and eradication of CSF. Maternal derived antibody (MDA) is the critical factor in impairing the efficacy of both MLV and E2 subunit vaccines, so the well-designed vaccination programs of sows and piglets should be considered together. Because of the antigen variation among various genotypes of CSFV, antibodies raised by either MLV or subunit vaccine neutralize genotypically homologous strains better than heterologous ones. However, although this is not a major concern for MLV as the induced immune responses can protect pigs against the challenge of various genotypes of CSFVs, it is critical for E2 subunit vaccines. It is thus necessary to evaluate whether the E2 subunit vaccine can completely protect against the current prevalent strains in the field. An ideal new generation of vaccine should be able to maintain the high protective efficiency of MLV and overcome the problem of antigenic variations while allowing for DIVA. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. SB-205384 Is a Positive Allosteric Modulator of Recombinant GABAA Receptors Containing Rat α3, α5, or α6 Subunit Subtypes Coexpressed with β3 and γ2 Subunits

    PubMed Central

    Heidelberg, Laura S.; Warren, James W.

    2013-01-01

    Many drugs used to treat anxiety are positive modulators of GABAA receptors, which mediate fast inhibitory neurotransmission. The GABAA receptors can be assembled from a combination of at least 16 different subunits. The receptor’s subunit composition determines its pharmacologic and functional properties, and subunit expression varies throughout the brain. A primary goal for new treatments targeting GABAA receptors is the production of subunit-selective modulators acting upon a discrete population of receptors. The anxiolytic 4-amino-7-hydroxy-2-methyl-5,6,7,8,-tetrahydrobenzo[b]thieno[2,3-b]pyridine-3-carboxylic acid, but-2-ynyl ester (SB-205384) is widely considered to be selective for α3-containing GABAA receptors. However, it has been tested only on α1-, α2-, and α3-containing receptors. We examined the activity of SB-205384 at recombinant receptors containing the six different α subunits and found that receptors containing the α3, α5, and α6 subunits were potentiated by SB-205384, with the α6 subunit conferring the greatest responsiveness. Properties associated with chimeric α1/α6 subunits suggested that multiple structural domains influence sensitivity to SB-205384. Point mutations of residues within the extracellular N-terminal domain identified a leucine residue located in loop E of the agonist binding site as an important determinant of high sensitivity to modulation. In the α6 subunit the identity of this residue is species-dependent, with the leucine found in rat subunits but not in human. Our results indicate that SB-205384 is not an α3-selective modulator, and instead acts at several GABAA receptor isoforms. These findings have implications for the side-effect profile of this anxiolytic as well as for its use in neuronal and animal studies as a marker for contribution from α3-containing receptors. PMID:23902941

  10. 21 CFR 884.4120 - Gynecologic electrocautery and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Gynecologic electrocautery and accessories. 884.4120 Section 884.4120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... under direct visual observation. This generic type of device may include the following accessories: an...

  11. 14 CFR 23.1192 - Engine accessory compartment diaphragm.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Engine accessory compartment diaphragm. 23... Powerplant Powerplant Fire Protection § 23.1192 Engine accessory compartment diaphragm. For aircooled radial engines, the engine power section and all portions of the exhaust sytem must be isolated from the engine...

  12. 14 CFR 23.1192 - Engine accessory compartment diaphragm.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Engine accessory compartment diaphragm. 23... Powerplant Powerplant Fire Protection § 23.1192 Engine accessory compartment diaphragm. For aircooled radial engines, the engine power section and all portions of the exhaust sytem must be isolated from the engine...

  13. 14 CFR 23.1192 - Engine accessory compartment diaphragm.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Engine accessory compartment diaphragm. 23... Powerplant Powerplant Fire Protection § 23.1192 Engine accessory compartment diaphragm. For aircooled radial engines, the engine power section and all portions of the exhaust sytem must be isolated from the engine...

  14. Rat nicotinic ACh receptor α7 and β2 subunits co-assemble to form functional heteromeric nicotinic receptor channels

    PubMed Central

    Khiroug, Serguei S; Harkness, Patricia C; Lamb, Patricia W; Sudweeks, Sterling N; Khiroug, Leonard; Millar, Neil S; Yakel, Jerrel L

    2002-01-01

    Rat hippocampal interneurons express diverse subtypes of functional nicotinic acetylcholine receptors (nAChRs), including α7-containing receptors that have properties unlike those expected for homomeric α7 nAChRs. We previously reported a strong correlation between expression of the α7 and of the β2 subunits in individual neurons. To explore whether co-assembly of the α7 and β2 subunits might occur, these subunits were co-expressed in Xenopus oocytes and the functional properties of heterologously expressed nAChRs were characterized by two-electrode voltage clamp. Co-expression of the β2 subunit, both wild-type and mutant forms, with the α7 subunit significantly slowed the rate of nAChR desensitization and altered the pharmacological properties. Whereas ACh, carbachol and choline were full or near-full agonists for homomeric α7 receptor channels, both carbachol and choline were only partial agonists in oocytes expressing both α7 and β2 subunits. In addition the EC50 values for all three agonists significantly increased when the β2 subunit was co-expressed with the α7 subunit. Co-expression with the β2 subunit did not result in any significant change in the current-voltage curve. Biochemical evidence for the co-assembly of the α7 and β2 subunits was obtained by co-immunoprecipitation of these subunits from transiently transfected human embryonic kidney (TSA201) cells. These data provide direct biophysical and molecular evidence that the nAChR α7 and β2 subunits co-assemble to form a functional heteromeric nAChR with functional and pharmacological properties different from those of homomeric α7 channels. This co-assembly may help to explain nAChR channel diversity in rat hippocampal interneurons, and perhaps in other areas of the nervous system. PMID:11956333

  15. Domain-domain interactions determine the gating, permeation, pharmacology, and subunit modulation of the IKs ion channel.

    PubMed

    Zaydman, Mark A; Kasimova, Marina A; McFarland, Kelli; Beller, Zachary; Hou, Panpan; Kinser, Holly E; Liang, Hongwu; Zhang, Guohui; Shi, Jingyi; Tarek, Mounir; Cui, Jianmin

    2014-12-23

    Voltage-gated ion channels generate electrical currents that control muscle contraction, encode neuronal information, and trigger hormonal release. Tissue-specific expression of accessory (β) subunits causes these channels to generate currents with distinct properties. In the heart, KCNQ1 voltage-gated potassium channels coassemble with KCNE1 β-subunits to generate the IKs current (Barhanin et al., 1996; Sanguinetti et al., 1996), an important current for maintenance of stable heart rhythms. KCNE1 significantly modulates the gating, permeation, and pharmacology of KCNQ1 (Wrobel et al., 2012; Sun et al., 2012; Abbott, 2014). These changes are essential for the physiological role of IKs (Silva and Rudy, 2005); however, after 18 years of study, no coherent mechanism explaining how KCNE1 affects KCNQ1 has emerged. Here we provide evidence of such a mechanism, whereby, KCNE1 alters the state-dependent interactions that functionally couple the voltage-sensing domains (VSDs) to the pore.

  16. Domain–domain interactions determine the gating, permeation, pharmacology, and subunit modulation of the IKs ion channel

    PubMed Central

    Zaydman, Mark A; Kasimova, Marina A; McFarland, Kelli; Beller, Zachary; Hou, Panpan; Kinser, Holly E; Liang, Hongwu; Zhang, Guohui; Shi, Jingyi; Tarek, Mounir; Cui, Jianmin

    2014-01-01

    Voltage-gated ion channels generate electrical currents that control muscle contraction, encode neuronal information, and trigger hormonal release. Tissue-specific expression of accessory (β) subunits causes these channels to generate currents with distinct properties. In the heart, KCNQ1 voltage-gated potassium channels coassemble with KCNE1 β-subunits to generate the IKs current (Barhanin et al., 1996; Sanguinetti et al., 1996), an important current for maintenance of stable heart rhythms. KCNE1 significantly modulates the gating, permeation, and pharmacology of KCNQ1 (Wrobel et al., 2012; Sun et al., 2012; Abbott, 2014). These changes are essential for the physiological role of IKs (Silva and Rudy, 2005); however, after 18 years of study, no coherent mechanism explaining how KCNE1 affects KCNQ1 has emerged. Here we provide evidence of such a mechanism, whereby, KCNE1 alters the state-dependent interactions that functionally couple the voltage-sensing domains (VSDs) to the pore. DOI: http://dx.doi.org/10.7554/eLife.03606.001 PMID:25535795

  17. Multiple functional roles of the accessory I-domain of bacteriophage P22 coat protein revealed by NMR structure and cryoEM modeling

    PubMed Central

    Rizzo, Alessandro A.; Suhanovsky, Margaret M.; Baker, Matthew L.; Fraser, LaTasha C.R.; Jones, Lisa M.; Rempel, Don L.; Gross, Michael L.; Chiu, Wah; Alexandrescu, Andrei T.; Teschke, Carolyn M.

    2014-01-01

    SUMMARY Some capsid proteins built on the ubiquitous HK97-fold have accessory domains that impart specific functions. Bacteriophage P22 coat protein has a unique inserted I-domain. Two prior I-domain models from sub-nanometer cryoEM reconstructions differed substantially. Therefore, the NMR structure of the I-domain was determined, which also was used to improve cryoEM models of coat protein. The I-domain has an anti-parallel 6-stranded β-barrel fold, previously not observed in HK97-fold accessory domains. The D-loop, which is dynamic both in the isolated I-domain and intact monomeric coat protein, forms stabilizing salt bridges between adjacent capsomers in procapsids. A newly described S-loop is important for capsid size determination, likely through intra-subunit interactions. Ten of eighteen coat protein temperature-sensitive-folding substitutions are in the I-domain, indicating its importance in folding and stability. Several are found on a positively charged face of the β-barrel that anchors the I-domain to a negatively charged surface of the coat protein HK97-core. PMID:24836025

  18. An α-subunit loop structure is required for GM2 activator protein binding by β-hexosaminidase A

    PubMed Central

    Zarghooni, Maryam; Bukovac, Scott; Tropak, Michael; Callahan, John; Mahuran, Don

    2010-01-01

    The α- and/or β-subunits of human β-hexosaminidase A (αβ) and B (ββ) are ~60% identical. In vivo only β-hexosaminidase A can utilize GM2 ganglioside as a substrate, but requires the GM2 activator protein to bind GM2 ganglioside and then interact with the enzyme, placing the terminal GalNAc residue in the active site of the α-subunit. A model for this interaction suggests that two loop structures, present only in the α-subunit, may be critical to this binding. Three amino acids in one of these loops are not encoded in the HEXB gene, while four from the other are removed posttranslationally from the pro-β-subunit. Natural substrate assays with forms of hexosaminidase A containing mutant α-subunits demonstrate that only the site that is removed from the β-subunit during its maturation is critical for the interaction. Our data suggest an unexpected biological role for such proteolytic processing events. PMID:15485660

  19. 14 CFR 125.149 - Engine accessory section diaphragm.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Engine accessory section diaphragm. 125.149... Requirements § 125.149 Engine accessory section diaphragm. Unless equivalent protection can be shown by other means, a diaphragm that complies with § 125.145 must be provided on air-cooled engines to isolate the...

  20. 14 CFR 125.149 - Engine accessory section diaphragm.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Engine accessory section diaphragm. 125.149... Requirements § 125.149 Engine accessory section diaphragm. Unless equivalent protection can be shown by other means, a diaphragm that complies with § 125.145 must be provided on air-cooled engines to isolate the...

  1. 14 CFR 125.149 - Engine accessory section diaphragm.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Engine accessory section diaphragm. 125.149... Requirements § 125.149 Engine accessory section diaphragm. Unless equivalent protection can be shown by other means, a diaphragm that complies with § 125.145 must be provided on air-cooled engines to isolate the...

  2. 14 CFR 125.149 - Engine accessory section diaphragm.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Engine accessory section diaphragm. 125.149... Requirements § 125.149 Engine accessory section diaphragm. Unless equivalent protection can be shown by other means, a diaphragm that complies with § 125.145 must be provided on air-cooled engines to isolate the...

  3. Construction of a hybrid β-hexosaminidase subunit capable of forming stable homodimers that hydrolyze GM2 ganglioside in vivo.

    PubMed

    Tropak, Michael B; Yonekawa, Sayuri; Karumuthil-Melethil, Subha; Thompson, Patrick; Wakarchuk, Warren; Gray, Steven J; Walia, Jagdeep S; Mark, Brian L; Mahuran, Don

    2016-01-01

    Tay-Sachs or Sandhoff disease result from mutations in either the evolutionarily related HEXA or HEXB genes encoding respectively, the α- or β-subunits of β-hexosaminidase A (HexA). Of the three Hex isozymes, only HexA can interact with its cofactor, the GM2 activator protein (GM2AP), and hydrolyze GM2 ganglioside. A major impediment to establishing gene or enzyme replacement therapy based on HexA is the need to synthesize both subunits. Thus, we combined the critical features of both α- and β-subunits into a single hybrid µ-subunit that contains the α-subunit active site, the stable β-subunit interface and unique areas in each subunit needed to interact with GM2AP. To facilitate intracellular analysis and the purification of the µ-homodimer (HexM), CRISPR-based genome editing was used to disrupt the HEXA and HEXB genes in a Human Embryonic Kidney 293 cell line stably expressing the µ-subunit. In association with GM2AP, HexM was shown to hydrolyze a fluorescent GM2 ganglioside derivative both in cellulo and in vitro. Gene transfer studies in both Tay-Sachs and Sandhoff mouse models demonstrated that HexM expression reduced brain GM2 ganglioside levels.

  4. Construction of a hybrid β-hexosaminidase subunit capable of forming stable homodimers that hydrolyze GM2 ganglioside in vivo

    PubMed Central

    Tropak, Michael B; Yonekawa, Sayuri; Karumuthil-Melethil, Subha; Thompson, Patrick; Wakarchuk, Warren; Gray, Steven J; Walia, Jagdeep S; Mark, Brian L; Mahuran, Don

    2016-01-01

    Tay-Sachs or Sandhoff disease result from mutations in either the evolutionarily related HEXA or HEXB genes encoding respectively, the α- or β-subunits of β-hexosaminidase A (HexA). Of the three Hex isozymes, only HexA can interact with its cofactor, the GM2 activator protein (GM2AP), and hydrolyze GM2 ganglioside. A major impediment to establishing gene or enzyme replacement therapy based on HexA is the need to synthesize both subunits. Thus, we combined the critical features of both α- and β-subunits into a single hybrid µ-subunit that contains the α-subunit active site, the stable β-subunit interface and unique areas in each subunit needed to interact with GM2AP. To facilitate intracellular analysis and the purification of the µ-homodimer (HexM), CRISPR-based genome editing was used to disrupt the HEXA and HEXB genes in a Human Embryonic Kidney 293 cell line stably expressing the µ-subunit. In association with GM2AP, HexM was shown to hydrolyze a fluorescent GM2 ganglioside derivative both in cellulo and in vitro. Gene transfer studies in both Tay-Sachs and Sandhoff mouse models demonstrated that HexM expression reduced brain GM2 ganglioside levels. PMID:26966698

  5. Loss of G2 subunit of vacuolar-type proton transporting ATPase leads to G1 subunit upregulation in the brain

    PubMed Central

    Kawamura, Nobuyuki; Sun-Wada, Ge-Hong; Wada, Yoh

    2015-01-01

    Vacuolar-type ATPase (V-ATPase) is a primary proton pump with versatile functions in various tissues. In nerve cells, V-ATPase is required for accumulation of neurotransmitters into secretory vesicles and subsequent release at the synapse. Neurons express a specific isoform (G2) of the G subunit of V-ATPase constituting the catalytic sector of the enzyme complex. Using gene targeting, we generated a mouse lacking functional G2 (G2 null), which showed no apparent disorders in architecture and behavior. In the G2-null mouse brain, a G1 subunit isoform, which is ubiquitously expressed in neuronal and non-neuronal tissues, accumulated more abundantly than in wild-type animals. This G1 upregulation was not accompanied by an increase in mRNA. These results indicate that loss of function of neuron-specific G2 isoform was compensated by an increase in levels of the G1 isoform without apparent upregulation of the G1 mRNA. PMID:26353914

  6. Structural Determinants for Functional Coupling Between the β and α Subunits in the Ca2+-activated K+ (BK) Channel

    PubMed Central

    Orio, Patricio; Torres, Yolima; Rojas, Patricio; Carvacho, Ingrid; Garcia, Maria L.; Toro, Ligia; Valverde, Miguel A.; Latorre, Ramon

    2006-01-01

    High conductance, calcium- and voltage-activated potassium (BK, MaxiK) channels are widely expressed in mammals. In some tissues, the biophysical properties of BK channels are highly affected by coexpression of regulatory (β) subunits. The most remarkable effects of β1 and β2 subunits are an increase of the calcium sensitivity and the slow down of channel kinetics. However, the detailed characteristics of channels formed by α and β1 or β2 are dissimilar, the most remarkable difference being a reduction of the voltage sensitivity in the presence of β1 but not β2. Here we reveal the molecular regions in these β subunits that determine their differential functional coupling with the pore-forming α-subunit. We made chimeric constructs between β1 and β2 subunits, and BK channels formed by α and chimeric β subunits were expressed in Xenopus laevis oocytes. The electrophysiological characteristics of the resulting channels were determined using the patch clamp technique. Chimeric exchange of the different regions of the β1 and β2 subunits demonstrates that the NH3 and COOH termini are the most relevant regions in defining the behavior of either subunit. This strongly suggests that the intracellular domains are crucial for the fine tuning of the effects of these β subunits. Moreover, the intracellular domains of β1 are responsible for the reduction of the BK channel voltage dependence. This agrees with previous studies that suggested the intracellular regions of the α-subunit to be the target of the modulation by the β1-subunit. PMID:16446507

  7. The Upregulation of α2δ-1 Subunit Modulates Activity-Dependent Ca2+ Signals in Sensory Neurons

    PubMed Central

    Margas, Wojciech; Cassidy, John S.

    2015-01-01

    As auxiliary subunits of voltage-gated Ca2+ channels, the α2δ proteins modulate membrane trafficking of the channels and their localization to specific presynaptic sites. Following nerve injury, upregulation of the α2δ-1 subunit in sensory dorsal root ganglion neurons contributes to the generation of chronic pain states; however, very little is known about the underlying molecular mechanisms. Here we show that the increased expression of α2δ-1 in rat sensory neurons leads to prolonged Ca2+ responses evoked by membrane depolarization. This mechanism is coupled to CaV2.2 channel-mediated responses, as it is blocked by a ω-conotoxin GVIA application. Once initiated, the prolonged Ca2+ transients are not dependent on extracellular Ca2+ and do not require Ca2+ release from the endoplasmic reticulum. The selective inhibition of mitochondrial Ca2+ uptake demonstrates that α2δ-1-mediated prolonged Ca2+ signals are buffered by mitochondria, preferentially activated by Ca2+ influx through CaV2.2 channels. Thus, by controlling channel abundance at the plasma membrane, the α2δ-1 subunit has a major impact on the organization of depolarization-induced intracellular Ca2+ signaling in dorsal root ganglion neurons. PMID:25878262

  8. Ferulic Acid Attenuates the Injury-Induced Decrease of Protein Phosphatase 2A Subunit B in Ischemic Brain Injury

    PubMed Central

    Koh, Phil-Ok

    2013-01-01

    Background Ferulic acid provides a neuroprotective effect during cerebral ischemia through its anti-oxidant function. Protein phosphatase 2A (PP2A) is a serine and threonine phosphatase that contributes broadly to normal brain function. This study investigated whether ferulic acid regulates PP2A subunit B in a middle cerebral artery occlusion (MCAO) animal model and glutamate toxicity-induced neuronal cell death. Methodology/Principal Findings MCAO was surgically induced to yield permanent cerebral ischemic injury in rats. The rats were treated with either vehicle or ferulic acid (100 mg/kg, i.v.) immediately after MCAO, and cerebral cortex tissues were collected 24 h after MCAO. A proteomics approach, RT-PCR, and Western blot analyses performed to identification of PP2A subunit B expression levels. Ferulic acid significantly reduced the MCAO-induced infarct volume of the cerebral cortex. A proteomics approach elucidated the reduction of PP2A subunit B in MCAO-induced animals, and ferulic acid treatment prevented the injury-induced reduction in PP2A subunit B levels. RT-PCR and Western blot analyses also showed that ferulic acid treatment attenuates the injury-induced decrease in PP2A subunit B levels. Moreover, the number of PP2A subunit B-positive cells was reduced in MCAO-induced animals, and ferulic acid prevented these decreases. In cultured neuronal cells, ferulic acid treatment protected cells against glutamate toxicity and prevented the glutamate-induced decrease in PP2A subunit B. Conclusions/Significance These results suggest that the maintenance of PP2A subunit B by ferulic acid in ischemic brain injury plays an important role for the neuroprotective function of ferulic acid. PMID:23349830

  9. Thermomechanical milling of accessory lithics in volcanic conduits

    NASA Astrophysics Data System (ADS)

    Campbell, Michelle E.; Russell, James K.; Porritt, Lucy A.

    2013-09-01

    Accessory lithic clasts recovered from pyroclastic deposits commonly result from the failure of conduit wall rocks, and represent an underutilized resource for constraining conduit processes during explosive volcanic eruptions. The morphological features of lithic clasts provide distinctive 'textural fingerprints' of processes that have reshaped them during transport in the conduit. Here, we present the first study focused on accessory lithic clast morphology and show how the shapes and surfaces of these accessory pyroclasts can inform on conduit processes. We use two main types of accessory lithic clasts from pyroclastic fallout deposits of the 2360 B.P. subplinian eruption of Mount Meager, British Columbia, as a case study: (i) rough and subangular dacite clasts, and (ii) variably rounded and smoothed monzogranite clasts. The quantitative morphological data collected on these lithics include: mass, volume, density, 2-D image analysis of convexity (C), and 3-D laser scans for sphericity (Ψ) and smoothness (S). Shaping and comminution (i.e. milling) of clasts within the conduit are ascribed to three processes: (1) disruptive fragmentation due to high-energy impacts between clasts or between clasts and conduit walls, (2) ash-blasting of clasts suspended within the volcanic flux, and (3) thermal effects. We use a simplified conduit eruption model to predict ash-blasting velocities and lithic residence times as a function of clast size and source depth, thereby constraining the lithic milling processes. The extent of shape and surface modification (i.e. rounding and honing) is directly proportional to clast residence times within the conduit prior to evacuation. We postulate that the shallow-seated dacite clasts remain subangular and rough due to short (<2 min) residence times, whereas monzogranite clasts are much more rounded and smoothed due to deeper source depths and consequently longer residence times (up to ˜1 h). Larger monzogranite clasts are smoother than

  10. 21 CFR 884.2660 - Fetal ultrasonic monitor and accessories.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Fetal ultrasonic monitor and accessories. 884.2660... (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Obstetrical and Gynecological Monitoring Devices § 884.2660 Fetal ultrasonic monitor and accessories. (a) Identification. A fetal ultrasonic...

  11. 21 CFR 884.2660 - Fetal ultrasonic monitor and accessories.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Fetal ultrasonic monitor and accessories. 884.2660... (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Obstetrical and Gynecological Monitoring Devices § 884.2660 Fetal ultrasonic monitor and accessories. (a) Identification. A fetal ultrasonic...

  12. 21 CFR 884.2660 - Fetal ultrasonic monitor and accessories.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Fetal ultrasonic monitor and accessories. 884.2660... (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Obstetrical and Gynecological Monitoring Devices § 884.2660 Fetal ultrasonic monitor and accessories. (a) Identification. A fetal ultrasonic...

  13. 21 CFR 874.4680 - Bronchoscope (flexible or rigid) and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... (flexible or rigid) and accessories. (a) Identification. A bronchoscope (flexible or rigid) and accessories... bronchoscope and is intended to examine or treat the larynx and tracheobronchial tree. It is typically used...

  14. Spinal Accessory Motor Neurons in the Mouse: A Special Type of Branchial Motor Neuron?

    PubMed

    Watson, Charles; Tvrdik, Petr

    2018-04-16

    The spinal accessory nerve arises from motor neurons in the upper cervical spinal cord. The axons of these motor neurons exit dorsal to the ligamentum denticulatum and form the spinal accessory nerve. The nerve ascends in the spinal subarachnoid space to enter the posterior cranial fossa through the foramen magnum. The spinal accessory nerve then turns caudally to exit through the jugular foramen alongside the vagus and glossopharyngeal nerves, and then travels to supply the sternomastoid and trapezius muscles in the neck. The unusual course of the spinal accessory nerve has long prompted speculation that it is not a typical spinal motor nerve and that it might represent a caudal remnant of the branchial motor system. Our cell lineage tracing data, combined with images from public databases, show that the spinal accessory motor neurons in the mouse transiently express Phox2b, a transcription factor that is required for development of brain stem branchial motor nuclei. While this is strong prima facie evidence that the spinal accessory motor neurons should be classified as branchial motor, the evolutionary history of these motor neurons in anamniote vertebrates suggests that they may be considered to be an atypical branchial group that possesses both branchial and somatic characteristics. Anat Rec, 2018. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

  15. Accessory mental foramina and nerves: Application to periodontal, periapical, and implant surgery.

    PubMed

    Iwanaga, Joe; Watanabe, Koichi; Saga, Tsuyoshi; Tabira, Yoko; Kitashima, Sadaharu; Kusukawa, Jingo; Yamaki, Koh-Ichi

    2016-05-01

    Recent studies investigating accessory mental foramina using developments in diagnostic imaging have primarily defined the morphology of the foramina; however, few studies have described the structures passing through them. Additional clinical knowledge of the foramina is therefore required for preoperative diagnosis prior to surgery, including implant, periodontal and periapical surgery. In this study, we investigated the accessory mental foramina and the associated nerves and arteries in donated cadaveric mandibles using anatomical and radiological observation methods. We examined 63 mandibles with overlying soft tissue by cone-beam computed tomography and noted the existence of the accessory mental foramina. Mandibles with accessory mental foramina were subsequently analyzed. Additionally, the neurovascular bundles passing through these foramina were dissected using anatomical methods.The incidence of accessory mental foramina was 14.3%. The larger foramina tended to be located anteriorly or superiorly and proximal to the mental foramen, while the smaller foramina tended to be located posterosuperiorly and distal to the mental foramen. The mental foramen ipsilateral to the accessory mental foramen was smaller than the one contralateral to it. The comparatively distant and large accessory mental foramen included an artery.This study elucidated the relationship between accessory mental foramina and the associated nerves and arteries. We believe that the results will contribute to the clinical dentistry field. © 2015 Wiley Periodicals, Inc.

  16. 21 CFR 884.2700 - Intrauterine pressure monitor and accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Intrauterine pressure monitor and accessories. 884.2700 Section 884.2700 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... include the following accessories: signal analysis and display equipment, patient and equipment supports...

  17. 21 CFR 884.2640 - Fetal phonocardiographic monitor and accessories.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Fetal phonocardiographic monitor and accessories. 884.2640 Section 884.2640 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... includes the following accessories: signal analysis and display equipment, patient and equipment supports...

  18. 21 CFR 884.2640 - Fetal phonocardiographic monitor and accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Fetal phonocardiographic monitor and accessories. 884.2640 Section 884.2640 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... includes the following accessories: signal analysis and display equipment, patient and equipment supports...

  19. 21 CFR 884.2700 - Intrauterine pressure monitor and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Intrauterine pressure monitor and accessories. 884.2700 Section 884.2700 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... include the following accessories: signal analysis and display equipment, patient and equipment supports...

  20. 21 CFR 884.2640 - Fetal phonocardiographic monitor and accessories.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Fetal phonocardiographic monitor and accessories. 884.2640 Section 884.2640 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... includes the following accessories: signal analysis and display equipment, patient and equipment supports...

  1. 21 CFR 884.2640 - Fetal phonocardiographic monitor and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Fetal phonocardiographic monitor and accessories. 884.2640 Section 884.2640 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... includes the following accessories: signal analysis and display equipment, patient and equipment supports...

  2. 21 CFR 884.2640 - Fetal phonocardiographic monitor and accessories.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Fetal phonocardiographic monitor and accessories. 884.2640 Section 884.2640 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... includes the following accessories: signal analysis and display equipment, patient and equipment supports...

  3. 21 CFR 884.2700 - Intrauterine pressure monitor and accessories.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Intrauterine pressure monitor and accessories. 884.2700 Section 884.2700 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... include the following accessories: signal analysis and display equipment, patient and equipment supports...

  4. Managing Brain Extracellular K+ during Neuronal Activity: The Physiological Role of the Na+/K+-ATPase Subunit Isoforms

    PubMed Central

    Larsen, Brian Roland; Stoica, Anca; MacAulay, Nanna

    2016-01-01

    During neuronal activity in the brain, extracellular K+ rises and is subsequently removed to prevent a widespread depolarization. One of the key players in regulating extracellular K+ is the Na+/K+-ATPase, although the relative involvement and physiological impact of the different subunit isoform compositions of the Na+/K+-ATPase remain unresolved. The various cell types in the brain serve a certain temporal contribution in the face of network activity; astrocytes respond directly to the immediate release of K+ from neurons, whereas the neurons themselves become the primary K+ absorbers as activity ends. The kinetic characteristics of the catalytic α subunit isoforms of the Na+/K+-ATPase are, partly, determined by the accessory β subunit with which they combine. The isoform combinations expressed by astrocytes and neurons, respectively, appear to be in line with the kinetic characteristics required to fulfill their distinct physiological roles in clearance of K+ from the extracellular space in the face of neuronal activity. Understanding the nature, impact and effects of the various Na+/K+-ATPase isoform combinations in K+ management in the central nervous system might reveal insights into pathological conditions such as epilepsy, migraine, and spreading depolarization following cerebral ischemia. In addition, particular neurological diseases occur as a result of mutations in the α2- (familial hemiplegic migraine type 2) and α3 isoforms (rapid-onset dystonia parkinsonism/alternating hemiplegia of childhood). This review addresses aspects of the Na+/K+-ATPase in the regulation of extracellular K+ in the central nervous system as well as the related pathophysiology. Understanding the physiological setting in non-pathological tissue would provide a better understanding of the pathological events occurring during disease. PMID:27148079

  5. Reconstructive surgery using interference screw fixation for painful accessory navicular in adult athletes.

    PubMed

    Miyamoto, Wataru; Takao, Masato; Yamada, Kazuaki; Yasui, Youichi; Matsushita, Takashi

    2012-10-01

    To examine the effectiveness of a new technique for reattaching the posterior tibial tendon (PTT) using a bone tunnel and interference screw after resection of the accessory navicular for painful accessory navicular (type II) in adult athletes. Ten adult athletes (7 male, 3 female; mean age 30 years, range 23-45) underwent reconstruction using a bone tunnel with an interference screw for a painful accessory navicular. All patients complained of pain on the medial aspect of the foot after eversion sprain during sports activities and radiographs revealed type II accessory navicular. Clinical evaluation with the American Orthopaedic Foot and Ankle Society Ankle-Hindfoot Scale (AOFAS) and visual analogue scale (VAS) before surgery was compared with that at most recent follow up (mean 30 months, range 24-39). Mean AOFAS score improved from a preoperative 62.8 ± 2.9 points (range 61-82) to a postoperative 92.1 ± 7.0 points (range 83-100; p < 0.01). Furthermore, mean VAS score improved from a preoperative 92.5 ± 5.4 points (range 85-100) to a postoperative 4.5 ± 3.8 points (range 0-10; p < 0.01). All patients could return to full sports activity at a mean of 14 weeks (range 12-18) after surgery. The presented technique reconstructs the bone-tendon interface of the PTT at the primary navicular with sufficient fixation after resection of the accessory navicular, which preserves the strength of the PTT in adult athletes with an intractably painful accessory navicular.

  6. 19 CFR 10.2020 - Accessories, spare parts, or tools.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 19 Customs Duties 1 2014-04-01 2014-04-01 false Accessories, spare parts, or tools. 10.2020 Section 10.2020 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY... Trade Promotion Agreement Rules of Origin § 10.2020 Accessories, spare parts, or tools. (a) General...

  7. 19 CFR 10.600 - Accessories, spare parts, or tools.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...-Central America-United States Free Trade Agreement Rules of Origin § 10.600 Accessories, spare parts, or... 10.600 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT... of the good's standard accessories, spare parts, or tools will be treated as originating goods if the...

  8. Overexpression of PP2A-C5 that encodes the catalytic subunit 5 of protein phosphatase 2A in Arabidopsis confers better root and shoot development under salt conditions

    USDA-ARS?s Scientific Manuscript database

    Protein phosphatase 2A (PP2A) is an enzyme consisting of three subunits: a scaffolding A subunit, a regulatory B subunit and a catalytic C subunit. PP2As were shown to play diverse roles in eukaryotes. In this study, the function of the Arabidopsis PP2A-C5 gene that encodes the catalytic subunit 5 o...

  9. The role of Ia molecules in the activation of T lymphocytes. I. The activation of an IL 1-dependent IL 2-producing T cell hybridoma by Con A requires an interaction, which is not H-2-restricted, with an Ia-bearing accessory cell.

    PubMed

    Rock, K L

    1982-10-01

    A model of accessory cell-dependent lectin-mediated T cell activation was investigated by utilizing a mitogen-inducible T cell hybridoma. A continuous MHC-restricted antigen-specific T cell line was fused with the azaguanine-resistant AKR thymoma BW5147. A hybrid, RF1.16B, was identified that is minimally inducible by Con A stimulation alone but is stimulated by Con A in the presence of T cell-depleted accessory cells to produce interleukin 2. The accessory cell function can be replaced by the monokine interleukin 1. Thus the lectin is a sufficient trigger for the hybrid in the absence of MHC restriction elements. The accessory cell function from splenocytes is provided by a non-B, non-T, predominantly Ia-bearing radioresistant cell. The interaction between the RF1.16B hybrid and the accessory cell population is not H-2-restricted. Control experiments, including the use of a cloned source of accessory cells, ruled out contaminating T cells or direct lectin effects as an explanation for the lack of H-2 restriction. The finding that an Ia-bearing cell is required for activation in an MHC-nonrestricted manner is discussed, and a hypothesis is raised that Ia antigens may play a role in addition to that of being a restriction element.

  10. Tyrosine Phosphorylation of GABAA Receptor γ2-Subunit Regulates Tonic and Phasic Inhibition in the Thalamus

    PubMed Central

    Nani, Francesca; Bright, Damian P.; Revilla-Sanchez, Raquel; Tretter, Verena; Moss, Stephen J.

    2013-01-01

    GABA-mediated tonic and phasic inhibition of thalamic relay neurons of the dorsal lateral geniculate nucleus (dLGN) was studied after ablating tyrosine (Y) phosphorylation of receptor γ2-subunits. As phosphorylation of γ2 Y365 and Y367 reduces receptor internalization, to understand their importance for inhibition we created a knock-in mouse in which these residues are replaced by phenylalanines. On comparing wild-type (WT) and γ2Y365/367F+/− (HT) animals (homozygotes are not viable in utero), the expression levels of GABAA receptor α4-subunits were increased in the thalamus of female, but not male mice. Raised δ-subunit expression levels were also observed in female γ2Y365/367F +/− thalamus. Electrophysiological analyses revealed no difference in the level of inhibition in male WT and HT dLGN, while both the spontaneous inhibitory postsynaptic activity and the tonic current were significantly augmented in female HT relay cells. The sensitivity of tonic currents to the δ-subunit superagonist THIP, and the blocker Zn2+, were higher in female HT relay cells. This is consistent with upregulation of extrasynaptic GABAA receptors containing α4- and δ-subunits to enhance tonic inhibition. In contrast, the sensitivity of GABAA receptors mediating inhibition in the female γ2Y356/367F +/− to neurosteroids was markedly reduced compared with WT. We conclude that disrupting tyrosine phosphorylation of the γ2-subunit activates a sex-specific increase in tonic inhibition, and this most likely reflects a genomic-based compensation mechanism for the reduced neurosteroid sensitivity of inhibition measured in female HT relay neurons. PMID:23904608

  11. Accessory neuropathy after sternotomy: Clinico-anatomical correlation supporting an inflammatory cause.

    PubMed

    Kassem, Mohammad W; Iwanaga, Joe; Loukas, Marios; Stone, Jonathan J; Smith, Jay; Spinner, Robert J; Tubbs, R Shane

    2018-04-01

    Inflammatory etiologies are becoming increasingly recognized as explanations of some neuropathies, especially those occurring in the perioperative period. Although "brachial neuritis" is known to affect extraplexal nerves, accessory nerve palsy following median sternotomy has been attributed to stretch on the nerve. To better elucidate stretch as a potential cause, a cadaveric study was performed. Two patients who developed accessory nerve palsy following median sternotomy are presented to illustrate features consistent with the diagnosis of a perioperative inflammatory neuropathy. Five adult unembalmed cadavers underwent exposure of the bilateral accessory nerves in the posterior cervical triangle. A median sternotomy was performed and self-retaining retractors positioned. With the head in neutral, left rotation and right rotation, retractors were opened as during surgery while observing and recording any accessory nerve movements. The self-retaining sternal retractors were fully opened to a mean inter-blade distance of 13 cm. Regardless of head position, from the initial retractor click to maximal opening there was no gross movement of the accessory nerve on the left or right sides. Opening self-retaining sternal retractors does not appear to stretch the accessory nerve in the posterior cervical triangle. Based on our clinical experience and cadaveric results, we believe that inflammatory conditions, (i.e., idiopathic brachial plexitis) can involve the accessory nerve, and might be triggered by surgical procedures. Clin. Anat. 31:417-421, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  12. Peristalsis is impaired in the small intestine of mice lacking the P2X3 subunit

    PubMed Central

    Bian, Xiaochun; Ren, Jianhua; De Vries, Matthew; Schnegelsberg, Birthe; Cockayne, Debra A; Ford, Anthony P D W; Galligan, James J

    2003-01-01

    P2X receptors are ATP-gated cation channels composed of one or more of seven different subunits. P2X receptors participate in intestinal neurotransmission but the subunit composition of enteric P2X receptors is unknown. In this study, we used tissues from P2X3 wild-type (P2X3+/+) mice and mice in which the P2X3 subunit gene had been deleted (P2X3−/−) to investigate the role of this subunit in neurotransmission in the intestine. RT-PCR analysis of mRNA from intestinal tissues verified P2X3 gene deletion. Intracellular electrophysiological methods were used to record synaptic and drug-induced responses from myenteric neurons in vitro. Drug-induced longitudinal muscle contractions were studied in vitro. Intraluminal pressure-induced reflex contractions (peristalsis) of ileal segments were studied in vitro using a modified Trendelenburg preparation. Gastrointestinal transit was measured as the progression in 30 min of a liquid radioactive marker administered by gavage to fasted mice. Fast excitatory postsynaptic potentials recorded from S neurons (motoneurons and interneurons) were similar in tissues from P2X3+/+ and P2X3−/− mice. S neurons from P2X3+/+ and P2X3−/− mice were depolarized by application of ATP but not α,β-methylene ATP, an agonist of P2X3 subunit-containing receptors. ATP and α,β-methylene ATP induced depolarization of AH (sensory) neurons from P2X3+/+ mice. ATP, but not α,β-methylene ATP, caused depolarization of AH neurons from P2X3−/− mice. Peristalsis was inhibited in ileal segments from P2X3−/− mice but longitudinal muscle contractions caused by nicotine and bethanechol were similar in segments from P2X3+/+ and P2X3−/− mice. Gastrointestinal transit was similar in P2X3+/+ and P2X3−/− mice. It is concluded that P2X3 subunit-containing receptors participate in neural pathways underlying peristalsis in the mouse intestine in vitro. P2X3 subunits are localized to AH (sensory) but not S neurons. P2X3 receptors may

  13. 21 CFR 884.2660 - Fetal ultrasonic monitor and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Fetal ultrasonic monitor and accessories. 884.2660... Devices § 884.2660 Fetal ultrasonic monitor and accessories. (a) Identification. A fetal ultrasonic monitor is a device designed to transmit and receive ultrasonic energy into and from the pregnant woman...

  14. Giant accessory breast: a rare occurrence reported, with a review of the literature.

    PubMed

    Hiremath, Bharati; Subramaniam, Narayana; Chandrashekhar, Nayan

    2015-11-05

    Polymastia, or the presence of supranumerary breasts, occurs in 2-6% of the female population, the spectrum of the disorder ranging between a small mole and a fully functional ectopic breast. They are often asymptomatic but require treatment when symptomatic or if they harbour malignancy. We present a case of a 41-year-old woman with an accessory breast in the left inframammary fold, which increased in size over the decade following her first pregnancy, to reach a size almost three times that of her right breast. Preoperative fine-needle aspiration and ultrasound was suggestive of accessory breast tissue, distinct from the left breast. Intraoperatively, a 14×10×8 cm accessory breast was found in the inframammary fold, distinct from the left breast and having an accessory nipple areola complex as well. A simple mastectomy was performed with trimming and rotation of the inframammary flap. The patient was happy with the cosmetic outcome. This article also reviews the literature and covers classification of polymastia, diagnostic complexities and challenges associated with surgery. 2015 BMJ Publishing Group Ltd.

  15. Giant accessory breast: a rare occurrence reported, with a review of the literature

    PubMed Central

    Hiremath, Bharati; Subramaniam, Narayana; Chandrashekhar, Nayan

    2015-01-01

    Polymastia, or the presence of supranumerary breasts, occurs in 2–6% of the female population, the spectrum of the disorder ranging between a small mole and a fully functional ectopic breast. They are often asymptomatic but require treatment when symptomatic or if they harbour malignancy. We present a case of a 41-year-old woman with an accessory breast in the left inframammary fold, which increased in size over the decade following her first pregnancy, to reach a size almost three times that of her right breast. Preoperative fine-needle aspiration and ultrasound was suggestive of accessory breast tissue, distinct from the left breast. Intraoperatively, a 14×10×8 cm accessory breast was found in the inframammary fold, distinct from the left breast and having an accessory nipple areola complex as well. A simple mastectomy was performed with trimming and rotation of the inframammary flap. The patient was happy with the cosmetic outcome. This article also reviews the literature and covers classification of polymastia, diagnostic complexities and challenges associated with surgery. PMID:26542818

  16. The GluN2A Subunit Regulates Neuronal NMDA receptor-Induced Microglia-Neuron Physical Interactions.

    PubMed

    Eyo, Ukpong B; Bispo, Ashley; Liu, Junting; Sabu, Sruchika; Wu, Rong; DiBona, Victoria L; Zheng, Jiaying; Murugan, Madhuvika; Zhang, Huaye; Tang, Yamei; Wu, Long-Jun

    2018-01-16

    Microglia are known to engage in physical interactions with neurons. However, our understanding of the detailed mechanistic regulation of microglia-neuron interactions is incomplete. Here, using high resolution two photon imaging, we investigated the regulation of NMDA receptor-induced microglia-neuron physical interactions. We found that the GluN2A inhibitor NVPAAM007, but not the GluN2B inhibitor ifenprodil, blocked the occurrence of these interactions. Consistent with the well-known developmental regulation of the GluN2A subunit, these interactions are absent in neonatal tissues. Furthermore, consistent with a preferential synaptic localization of GluN2A subunits, there is a differential sensitivity of their occurrence between denser (stratum radiatum) and less dense (stratum pyramidale) synaptic sub-regions of the CA1. Finally, consistent with differentially expressed GluN2A subunits in the CA1 and DG areas of the hippocampus, these interactions could not be elicited in the DG despite robust microglial chemotactic capabilities. Together, these results enhance our understanding of the mechanistic regulation of NMDA receptor-dependent microglia-neuronal physical interactions phenomena by the GluN2A subunit that may be relevant in the mammalian brain during heightened glutamatergic neurotransmission such as epilepsy and ischemic stroke.

  17. Accessory wandering spleen: Report of a case of laparoscopic approach in an asymptomatic patient

    PubMed Central

    Perin, Alessandro; Cola, Roberto; Favretti, Franco

    2014-01-01

    INTRODUCTION Accessory wandering spleen is a rare but dangerous condition. Abnormalities of the ligamentous apparatus of an accessory spleen may evolve into torsion of its vascular axis, which can lead to a splenic infarct making surgery necessary. Patients are often asymptomatic and the diagnosis can be accidental. An early diagnosis and a correct treatment are fundamental. PRESENTATION OF CASE In this case report a young woman underwent laparoscopic surgery after an incidental finding at a Pelvic Ultrasound of an accessory wandering spleen. DISCUSSION In literature are reported cases of asymptomatic patients with an accessory wandering spleen treated with a conservative approach. However, a torsion or infarct of the accessory wandering spleen leads to emergency surgery. The presence of an independent vascular axis of the accessory spleen reduces the risk of postoperative complications (e.g. thrombocytosis) and the administration of low molecular weight heparin should prevent the risk of portal thrombosis. CONCLUSION We suggest performing surgery with a laparoscopic approach in patients with accessory wandering spleen, though asymptomatic, because of the risk of serious complications in case of accessory spleen torsion. PMID:25460427

  18. Specific Roles of NMDA Receptor Subunits in Mental Disorders.

    PubMed

    Yamamoto, H; Hagino, Y; Kasai, S; Ikeda, K

    2015-01-01

    N-methyl-D-aspartate (NMDA) receptor plays important roles in learning and memory. NMDA receptors are a tetramer that consists of two glycine-binding subunits GluN1, two glutamate-binding subunits (i.e., GluN2A, GluN2B, GluN2C, and GluN2D), a combination of a GluN2 subunit and glycine-binding GluN3 subunit (i.e., GluN3A or GluN3B), or two GluN3 subunits. Recent studies revealed that the specific expression and distribution of each subunit are deeply involved in neural excitability, plasticity, and synaptic deficits. The present article summarizes reports on the dysfunction of NMDA receptors and responsible subunits in various neurological and psychiatric disorders, including schizophrenia, autoimmune-induced glutamatergic receptor dysfunction, mood disorders, and autism. A key role for the GluN2D subunit in NMDA receptor antagonist-induced psychosis has been recently revealed.

  19. Heterodimerization with the β1 subunit directs the α2 subunit of nitric oxide-sensitive guanylyl cyclase to calcium-insensitive cell-cell contacts in HEK293 cells: Interaction with Lin7a.

    PubMed

    Hochheiser, Julia; Haase, Tobias; Busker, Mareike; Sömmer, Anne; Kreienkamp, Hans-Jürgen; Behrends, Sönke

    2016-12-15

    Nitric oxide-sensitive guanylyl cyclase is a heterodimeric enzyme consisting of an α and a β subunit. Two different α subunits (α 1 and α 2 ) give rise to two heterodimeric enzymes α 1 /β 1 and α 2 /β 1 . Both coexist in a wide range of tissues including blood vessels and the lung, but expression of the α 2 /β 1 form is generally much lower and approaches levels similar to the α 1 /β 1 form in the brain only. In the present paper, we show that the α 2 /β 1 form interacts with Lin7a in mouse brain synaptosomes based on co-precipitation analysis. In HEK293 cells, we found that the overexpressed α 2 /β 1 form, but not the α 1 /β 1 form is directed to calcium-insensitive cell-cell contacts. The isolated PDZ binding motif of an amino-terminally truncated α 2 subunit was sufficient for cell-cell contact localization. For the full length α 2 subunit with the PDZ binding motif this was only the case in the heterodimer configuration with the β 1 subunit, but not as isolated α 2 subunit. We conclude that the PDZ binding motif of the α 2 subunit is only accessible in the heterodimer conformation of the mature nitric oxide-sensitive enzyme. Interaction with Lin7a, a small scaffold protein important for synaptic function and cell polarity, can direct this complex to nectin based cell-cell contacts via MPP3 in HEK293 cells. We conclude that heterodimerization is a prerequisite for further protein-protein interactions that direct the α 2 /β 1 form to strategic sites of the cell membrane with adjacent neighbouring cells. Drugs increasing the nitric oxide-sensitivity of this specific form may be particularly effective. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Loss of α2δ-1 Calcium Channel Subunit Function Increases the Susceptibility for Diabetes.

    PubMed

    Mastrolia, Vincenzo; Flucher, Sylvia M; Obermair, Gerald J; Drach, Mathias; Hofer, Helene; Renström, Erik; Schwartz, Arnold; Striessnig, Jörg; Flucher, Bernhard E; Tuluc, Petronel

    2017-04-01

    Reduced pancreatic β-cell function or mass is the critical problem in developing diabetes. Insulin release from β-cells depends on Ca 2+ influx through high voltage-gated Ca 2+ channels (HVCCs). Ca 2+ influx also regulates insulin synthesis and insulin granule priming and contributes to β-cell electrical activity. The HVCCs are multisubunit protein complexes composed of a pore-forming α 1 and auxiliary β and α 2 δ subunits. α 2 δ is a key regulator of membrane incorporation and function of HVCCs. Here we show that genetic deletion of α 2 δ-1, the dominant α 2 δ subunit in pancreatic islets, results in glucose intolerance and diabetes without affecting insulin sensitivity. Lack of the α 2 δ-1 subunit reduces the Ca 2+ currents through all HVCC isoforms expressed in β-cells equally in male and female mice. The reduced Ca 2+ influx alters the kinetics and amplitude of the global Ca 2+ response to glucose in pancreatic islets and significantly reduces insulin release in both sexes. The progression of diabetes in males is aggravated by a selective loss of β-cell mass, while a stronger basal insulin release alleviates the diabetes symptoms in most α 2 δ-1 -/- female mice. Together, these findings demonstrate that the loss of the Ca 2+ channel α 2 δ-1 subunit function increases the susceptibility for developing diabetes in a sex-dependent manner. © 2017 by the American Diabetes Association.

  1. Accessory breasts: a historical and current perspective.

    PubMed

    Loukas, Marios; Clarke, Pamela; Tubbs, R Shane

    2007-05-01

    The presence of accessory breast tissue such as extra nipples (polythelia) and extra breast (polymastia) is relatively common, with a high incidence of being misdiagnosed in clinical medicine. Although polythelia is congenital in origin and is identifiable at childhood, polymastia may not be evident until the influence of sex hormones during puberty. In this article, we present a review of the literature concerning the historical background of accessory breasts, their incidence, their misdiagnoses, and their association with other syndromes and diseases. Finally, we present the common treatment options available today for such conditions.

  2. Accessory proteins of SARS-CoV and other coronaviruses.

    PubMed

    Liu, Ding Xiang; Fung, To Sing; Chong, Kelvin Kian-Long; Shukla, Aditi; Hilgenfeld, Rolf

    2014-09-01

    The huge RNA genome of SARS coronavirus comprises a number of open reading frames that code for a total of eight accessory proteins. Although none of these are essential for virus replication, some appear to have a role in virus pathogenesis. Notably, some SARS-CoV accessory proteins have been shown to modulate the interferon signaling pathways and the production of pro-inflammatory cytokines. The structural information on these proteins is also limited, with only two (p7a and p9b) having their structures determined by X-ray crystallography. This review makes an attempt to summarize the published knowledge on SARS-CoV accessory proteins, with an emphasis on their involvement in virus-host interaction. The accessory proteins of other coronaviruses are also briefly discussed. This paper forms part of a series of invited articles in Antiviral Research on "From SARS to MERS: 10 years of research on highly pathogenic human coronaviruses" (see Introduction by Hilgenfeld and Peiris (2013)). Copyright © 2014 Elsevier B.V. All rights reserved.

  3. The benefits of using bluetooth accessories with hearing aids.

    PubMed

    Smith, Pauline; Davis, Adrian

    2014-10-01

    To investigate the benefits in reported outcomes after providing bluetooth accessories for established hearing aid users. Prospective observational study using validated quantitative outcome measures and detailed patient narrative before and two months after patients were provided with bluetooth accessories. Twelve patients with bilateral NHS hearing aids participated. They had a wide range of ages and hearing loss. After two months, 10 patients reported substantial additional benefit and kept the accessories; two returned them for various reasons. Statistically significant changes were seen in two validated outcome measures: the Glasgow Hearing Aid Benefit Profile and the International Outcome Inventory - Hearing Aids, but not in the Speech, Spatial and Qualities of Hearing Scale. Two notable benefits were reported: some described hearing the emotion and mood in a voice for the first time; others were amazed to report an improved ability to hear film or to hold conversations over the telephone. The provision of bluetooth accessories can give additional reported benefit for some patients - we need better knowledge about who benefits, and whether further support/training to individuals would make a difference.

  4. Correction of accessory axillary breast tissue without visible scar.

    PubMed

    Kim, Young Soo

    2004-01-01

    Various methods for correction of accessory axillary breast tissue have been proposed, including simple excision, diamond-shaped excision, a Y-V technique, and lipoplasty. We present an effective method for correction of a prominent axillary mound that combines lipoplasty with excision of accessory breast tissue along the axillary transverse line. Preoperative markings included an incision within the natural wrinkle line in the axillary fold, and demarcation of areas in which lipoplasty and excision were to be performed. After lipoplasty, deep dissection was performed to isolate and remove accessory breast tissue and excess fat tissue. A compression dressing was applied for 1 to 2 weeks postoperatively, and the patient was instructed to wear a sports bra for 1 to 2 months after removal of the dressing. We treated 7 patients using this procedure between October 1999 and March 2003. No major postoperative complications were detected and recurrence was not noted during the follow-up periods. Aesthetic results were satisfactory. We believe that a procedure that combines lipoplasty and excision provides numerous advantages as a surgical option in treating a prominent axillary mound. The main advantage is that the final scar is laid in the natural axillary fold, rendering scars less conspicuous and eliminating the need to remove excess skin. The one disadvantage was that elevation of the skin flap via small, remote incisions initially produced surgical difficulties, but these were overcome with experience.

  5. Crystallization of accessory phases in magmas by local saturation adjacent to phenocrysts

    USGS Publications Warehouse

    Bacon, C.R.

    1989-01-01

    Accessory minerals commonly occur attached to or included in the major crystalline phases of felsic and some intermediate igneous rocks. Apatite is particularly common as inclusions, but Fe-Ti oxides, pyrrhotite, zircon, monazite, chevkinite and xenotime are also known from silicic rocks. Accessories may nucleate near the host crystal/ liquid interface as a result of local saturation owing to formation of a differentiated chemical boundary layer in which accessory mineral solubility would be lower than in the surrounding liquid. Differentiation of this boundary layer would be greatest adjacent to ferromagnesian phenocrysts, especially Fe-Ti oxides; it is with oxides that accessories are most commonly associated in rocks. A boundary layer may develop if the crystal grows more rapidly than diffusion can transport incorporated and rejected elements to and from the phenocryst. Diffusion must dominate over convection as a mode of mass transfer near the advancing crystal/liquid interface in order for a boundary layer to exist. Accumulation of essential structural constituent elements of accessory minerals owing to their slow diffusion in evolved silicate melt also may force local saturation, but this is not a process that applies to all cases. Local saturation is an attractive mechanism for enhancing fractionation during crystallization differentiation. If accessory minerals attached to or included in phenocrysts formed because of local saturation, their host phenocrysts must have grown rapidly when accessories nucleated in comparison to lifetimes of magma reservoirs. Some inconsistencies remain in a local saturation origin for accessory phases that cannot be evaluated without additional information. ?? 1989.

  6. Identification and Characterization of an Alternatively Spliced Isoform of the Human Protein Phosphatase 2Aα Catalytic Subunit*

    PubMed Central

    Migueleti, Deivid L. S.; Smetana, Juliana H. C.; Nunes, Hugo F.; Kobarg, Jörg; Zanchin, Nilson I. T.

    2012-01-01

    PP2A is the main serine/threonine-specific phosphatase in animal cells. The active phosphatase has been described as a holoenzyme consisting of a catalytic, a scaffolding, and a variable regulatory subunit, all encoded by multiple genes, allowing for the assembly of more than 70 different holoenzymes. The catalytic subunit can also interact with α4, TIPRL (TIP41, TOR signaling pathway regulator-like), the methyl-transferase LCMT-1, and the methyl-esterase PME-1. Here, we report that the gene encoding the catalytic subunit PP2Acα can generate two mRNA types, the standard mRNA and a shorter isoform, lacking exon 5, which we termed PP2Acα2. Higher levels of the PP2Acα2 mRNA, equivalent to the level of the longer PP2Acα mRNA, were detected in peripheral blood mononuclear cells that were left to rest for 24 h. After this time, the peripheral blood mononuclear cells are still viable and the PP2Acα2 mRNA decreases soon after they are transferred to culture medium, showing that generation of the shorter isoform depends on the incubation conditions. FLAG-tagged PP2Acα2 expressed in HEK293 is catalytically inactive. It displays a specific interaction profile with enhanced binding to the α4 regulatory subunit, but no binding to the scaffolding subunit and PME-1. Consistently, α4 out-competes PME-1 and LCMT-1 for binding to both PP2Acα isoforms in pulldown assays. Together with molecular modeling studies, this suggests that all three regulators share a common binding surface on the catalytic subunit. Our findings add important new insights into the complex mechanisms of PP2A regulation. PMID:22167190

  7. Genetic analysis of neuronal ionotropic glutamate receptor subunits

    PubMed Central

    Granger, Adam J; Gray, John A; Lu, Wei; Nicoll, Roger A

    2011-01-01

    Abstract In the brain, fast, excitatory synaptic transmission occurs primarily through AMPA- and NMDA-type ionotropic glutamate receptors. These receptors are composed of subunit proteins that determine their biophysical properties and trafficking behaviour. Therefore, determining the function of these subunits and receptor subunit composition is essential for understanding the physiological properties of synaptic transmission. Here, we discuss and evaluate various genetic approaches that have been used to study AMPA and NMDA receptor subunits. These approaches have demonstrated that the GluA1 AMPA receptor subunit is required for activity-dependent trafficking and contributes to basal synaptic transmission, while the GluA2 subunit regulates Ca2+ permeability, homeostasis and trafficking to the synapse under basal conditions. In contrast, the GluN2A and GluN2B NMDA receptor subunits regulate synaptic AMPA receptor content, both during synaptic development and plasticity. Ongoing research in this field is focusing on the molecular interactions and mechanisms that control these functions. To accomplish this, molecular replacement techniques are being used, where native subunits are replaced with receptors containing targeted mutations. In this review, we discuss a single-cell molecular replacement approach which should arguably advance our physiological understanding of ionotropic glutamate receptor subunits, but is generally applicable to study of any neuronal protein. PMID:21768264

  8. Genetic analysis of neuronal ionotropic glutamate receptor subunits.

    PubMed

    Granger, Adam J; Gray, John A; Lu, Wei; Nicoll, Roger A

    2011-09-01

    In the brain, fast, excitatory synaptic transmission occurs primarily through AMPA- and NMDA-type ionotropic glutamate receptors. These receptors are composed of subunit proteins that determine their biophysical properties and trafficking behaviour. Therefore, determining the function of these subunits and receptor subunit composition is essential for understanding the physiological properties of synaptic transmission. Here, we discuss and evaluate various genetic approaches that have been used to study AMPA and NMDA receptor subunits. These approaches have demonstrated that the GluA1 AMPA receptor subunit is required for activity-dependent trafficking and contributes to basal synaptic transmission, while the GluA2 subunit regulates Ca(2+) permeability, homeostasis and trafficking to the synapse under basal conditions. In contrast, the GluN2A and GluN2B NMDA receptor subunits regulate synaptic AMPA receptor content, both during synaptic development and plasticity. Ongoing research in this field is focusing on the molecular interactions and mechanisms that control these functions. To accomplish this, molecular replacement techniques are being used, where native subunits are replaced with receptors containing targeted mutations. In this review, we discuss a single-cell molecular replacement approach which should arguably advance our physiological understanding of ionotropic glutamate receptor subunits, but is generally applicable to study of any neuronal protein.

  9. 26 CFR 48.4061(b)-3 - Rebuilt, reconditioned, or repaired parts or accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., reconditioned, or repaired parts or accessories. (a) Rebuilt parts or accessories. Rebuilding of automobile... for the person reassembling the generator, (6) reground or remetalized crankshafts, and (7) engines in... reassembling (with any necessary replacements of worn parts) of automobile parts or accessories, such as fuel...

  10. 26 CFR 48.4061(b)-3 - Rebuilt, reconditioned, or repaired parts or accessories.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ..., reconditioned, or repaired parts or accessories. (a) Rebuilt parts or accessories. Rebuilding of automobile... for the person reassembling the generator, (6) reground or remetalized crankshafts, and (7) engines in... reassembling (with any necessary replacements of worn parts) of automobile parts or accessories, such as fuel...

  11. 26 CFR 48.4061(b)-3 - Rebuilt, reconditioned, or repaired parts or accessories.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ..., reconditioned, or repaired parts or accessories. (a) Rebuilt parts or accessories. Rebuilding of automobile... for the person reassembling the generator, (6) reground or remetalized crankshafts, and (7) engines in... reassembling (with any necessary replacements of worn parts) of automobile parts or accessories, such as fuel...

  12. 14 CFR 221.52 - Airport to airport application, accessorial services.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Airport to airport application, accessorial... Charges § 221.52 Airport to airport application, accessorial services. Tariffs shall specify whether or not the fares therein include services in addition to airport-to-airport transportation. ...

  13. 14 CFR 221.52 - Airport to airport application, accessorial services.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Airport to airport application, accessorial... Charges § 221.52 Airport to airport application, accessorial services. Tariffs shall specify whether or not the fares therein include services in addition to airport-to-airport transportation. ...

  14. 14 CFR 221.52 - Airport to airport application, accessorial services.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Airport to airport application, accessorial... Charges § 221.52 Airport to airport application, accessorial services. Tariffs shall specify whether or not the fares therein include services in addition to airport-to-airport transportation. ...

  15. 14 CFR 221.52 - Airport to airport application, accessorial services.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Airport to airport application, accessorial... Charges § 221.52 Airport to airport application, accessorial services. Tariffs shall specify whether or not the fares therein include services in addition to airport-to-airport transportation. ...

  16. 14 CFR 221.52 - Airport to airport application, accessorial services.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Airport to airport application, accessorial... Charges § 221.52 Airport to airport application, accessorial services. Tariffs shall specify whether or not the fares therein include services in addition to airport-to-airport transportation. ...

  17. The KCNE2 K+ channel regulatory subunit: ubiquitous influence, complex pathobiology

    PubMed Central

    Abbott, Geoffrey W.

    2015-01-01

    The KCNE single-span transmembrane subunits are encoded by five-member gene families in the human and mouse genomes. Primarily recognized for co-assembling with and functionally regulating the voltage-gated potassium channels, the broad influence of KCNE subunits in mammalian physiology belies their small size. KCNE2 has been widely studied since we first discovered one of its roles in the heart and its association with inherited and acquired human Long QT syndrome. Since then, physiological analyses together with human and mouse genetics studies have uncovered a startling array of functions for KCNE2, in the heart, stomach, thyroid and choroid plexus. The other side of this coin is the variety of interconnected disease manifestations caused by KCNE2 disruption, involving both excitable cells such as cardiomyocytes, and non-excitable, polarized epithelia. Kcne2 deletion in mice has been particularly instrumental in illustrating the potential ramifications within a monogenic arrhythmia syndrome, with removal of one piece revealing the unexpected complexity of the puzzle. Here, we review current knowledge of the function and pathobiology of KCNE2. PMID:26123744

  18. Toll-Like Receptor 2 Mediates Cellular Activation by the B Subunits of Type II Heat-Labile Enterotoxins

    PubMed Central

    Hajishengallis, George; Tapping, Richard I.; Martin, Michael H.; Nawar, Hesham; Lyle, Elizabeth A.; Russell, Michael W.; Connell, Terry D.

    2005-01-01

    The type II heat-labile enterotoxins (LT-IIa and LT-IIb) of Escherichia coli have an AB5 subunit structure similar to that of cholera toxin (CT) and other type I enterotoxins, despite significant differences in the amino acid sequences of their B subunits and different ganglioside receptor specificities. LT-II holotoxins and their nontoxic B subunits display unique properties as immunological adjuvants distinct from those of CT and its B subunits. In contrast to type II holotoxins, the corresponding pentameric B subunits, LT-IIaB and LT-IIbB, stimulated cytokine release in both human and mouse cells dependent upon Toll-like receptor 2 (TLR2). Induction of interleukin-1β (IL-1β), IL-6, IL-8, or tumor necrosis factor alpha in human THP-1 cells by LT-IIaB or LT-IIbB was inhibited by anti-TLR2 but not by anti-TLR4 antibody. Furthermore, transient expression of TLR1 and TLR2 in human embryonic kidney 293 cells resulted in activation of a nuclear factor-κB-dependent luciferase gene in response to LT-IIaB or LT-IIbB. Moreover, peritoneal macrophages from TLR2-deficient mice failed to respond to LT-IIaB or LT-IIbB, in contrast to wild-type or TLR4-deficient cells. These results demonstrate that besides their established binding to gangliosides, the B subunits of type II enterotoxins also interact with TLR2. Although a ganglioside-nonbinding mutant (T34I) of LT-IIaB effectively induced cytokine release, a phenotypically similar point mutation (T13I) in LT-IIbB abrogated cytokine induction, suggesting a variable requirement for gangliosides as coreceptors in TLR2 agonist activity. TLR2-dependent activation of mononuclear cells by type II enterotoxin B subunits appears to be a novel mechanism whereby these molecules may exert their immunomodulatory and adjuvant activities. PMID:15731031

  19. A dynamic alpha-beta inter-subunit agonist signaling complex is a novel feedback mechanism for regulating L-type Ca2+ channel opening.

    PubMed

    Zhang, Rong; Dzhura, Igor; Grueter, Chad E; Thiel, William; Colbran, Roger J; Anderson, Mark E

    2005-09-01

    L-type Ca2+ channels are macromolecular protein complexes in neurons and myocytes that open in response to cell membrane depolarization to supply Ca2+ for regulating gene transcription and vesicle secretion and triggering cell contraction. L-type Ca2+ channels include a pore-forming alpha and an auxiliary beta subunit, and alpha subunit openings are regulated by cellular Ca2+ through a mechanism involving the Ca2+-sensing protein calmodulin (CaM) and CaM binding motifs in the alpha subunit cytoplasmic C terminus. Here we show that these CaM binding motifs are "auto-agonists" that increase alpha subunit openings by binding the beta subunit. The CaM binding domains are necessary and sufficient for the alpha subunit C terminus to bind the beta subunit in vitro, and excess CaM blocks this interaction. Addition of CaM binding domains to native cardiac L-type Ca2+ channels in excised cell membrane patches increases openings, and this agonist effect is prevented by excess CaM. Recombinant LTCC openings are also increased by exogenous CaM binding domains by a mechanism requiring the beta subunit, and excess CaM blocks this effect. Thus, the bifunctional ability of the alpha subunit CaM binding motifs to competitively associate with the beta subunit or CaM provides a novel paradigm for feedback control of cellular Ca2+ entry.

  20. Accessory mineral records of tectonic environments? (Invited)

    NASA Astrophysics Data System (ADS)

    Storey, C.; Marschall, H. R.; Enea, F.; Taylor, J.; Jennings, E. S.

    2010-12-01

    Accessory mineral research continues to gather momentum as we seek to unleash their full potential. It is now widely recognised that robust accessory minerals, such as zircon, rutile, titanite, allanite and monazite, are archives of important trace elements that can help deduce metamorphic reaction history in metapelites, metabasites and other rock types. Moreover, they are important carriers of certain trace elements and govern or influence the products of partial melting and of fluid-rock interaction (e.g. magmas and mineralisation) in settings like subduction zones and hydrothermal systems. Perhaps most importantly, they can often be dated using the U-Th-Pb system. More recently, radiogenic (Lu-Hf, Sm-Nd, Rb-Sr) and stable (O) isotope systems have been applied and have further pushed the utility of accessory mineral research. In this talk I will discuss some of these advances towards one particular aim: the use of detrital accessory minerals for fingerprinting tectonic environments. This is a particularly laudable aim in Precambrian rocks, for which the preservation potential of orogenic belts and fossil subduction zones and their diagnostic metamorphic rocks is low. The implication is that our understanding of plate tectonics, particularly in the Archaean, is biased by the preserved in-tact rock record. An analogy is that Jack Hills zircons record evidence of Earth’s crust some 400 Ma before the preserved rock record begins. I will focus on some recent advances and new data from rutile and also the mineral inclusion record within zircon, which shows great promise for petrologic interpretation.

  1. Accessory Devices Frequently Used for Endoscopic Submucosal Dissection

    PubMed Central

    Choi, Hyuk Soon; Chun, Hoon Jai

    2017-01-01

    Endoscopic submucosal dissection (ESD) is increasingly being considered an essential component of treatment for early gastrointestinal cancers and subepithelial tumors. The ESD technique owes its popularity to the development of sophisticated instruments used for ESD. With an increase in the number of ESD procedures performed, there is rapid development in the number and types of endoscopic accessory devices used for such procedures. Despite the large numbers of new devices developed and marketed, the use of ESD instruments and accessory devices is largely determined by individual preferences and experiences. Accessory devices frequently used during ESD are important tools for ESD techniques. Each instrument possesses characteristic advantages and disadvantages associated with its use, and no one instrument is superior in all respects to others. In this article, we review the characteristics of endoscopic electrical knives, cap and hood, and hemostatic devices commonly used in ESD. PMID:28609818

  2. Does the presence of accessory renal arteries affect the efficacy of renal denervation?

    PubMed

    Id, Dani; Kaltenbach, Benjamin; Bertog, Stefan C; Hornung, Marius; Hofmann, Ilona; Vaskelyte, Laura; Sievert, Horst

    2013-10-01

    This study sought to assess the efficacy of catheter-based renal sympathetic denervation in patients with accessory renal arteries and to compare the blood pressure (BP)-lowering effect with that observed in patients with bilateral single renal arteries after renal denervation. Catheter-based renal sympathetic denervation causes significant BP reductions in patients with resistant hypertension. Seventy-four patients were included in this study. Patients were assigned to 2 main groups: a bilateral single renal arteries group I (n = 54) and an accessory renal arteries group II (n = 20). Group II consisted of 9 patients whose accessory renal arteries were all denervated (group IIa), and 11 patients whose accessory renal arteries were not, or only incompletely, denervated (group IIb). The primary endpoint was the change in office systolic BP after 6 months. The procedure was successful in all patients. Group I: mean BP at baseline was 166.2/89.4 ± 20.5/14.6 mm Hg and decreased by -16.6 (p < 0.001)/-6.7 (p = 0.016) ± 16.4/11 mm Hg at 6-month follow-up. Group II: mean BP at baseline was 164.2/89.1 ± 19.9/15.4 mm Hg and decreased by -6.2 (p = 0.19)/-0.2 (p = 0.5) ± 19.7/11.3 mm Hg at 6-month follow-up. Patients in group IIa had an office BP reduction of -8.8 (p = 0.2)/1.1 ± 17.9/10.8 mm Hg and patients in group IIb of -4.1 (p = 0.55)/-1.3 ± 20.8/11.6 mm Hg. Similarly, significant improvements in 24-h mean systolic BP were seen in group I (-8.3 ± 17.4 mm Hg, p < 0.01), whereas none were seen in group II (-3.7 ± 8.3 mm Hg, p = 0.38). BP reduction achieved after renal denervation in patients with accessory renal arteries is less pronounced than in patients with bilateral single renal arteries. Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  3. 21 CFR 884.1300 - Uterotubal carbon dioxide insufflator and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Uterotubal carbon dioxide insufflator and... Gynecological Diagnostic Devices § 884.1300 Uterotubal carbon dioxide insufflator and accessories. (a) Identification. A uterotubal carbon dioxide insufflator and accessories is a device used to test the patency...

  4. 21 CFR 884.1300 - Uterotubal carbon dioxide insufflator and accessories.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Uterotubal carbon dioxide insufflator and... Gynecological Diagnostic Devices § 884.1300 Uterotubal carbon dioxide insufflator and accessories. (a) Identification. A uterotubal carbon dioxide insufflator and accessories is a device used to test the patency...

  5. 21 CFR 884.1300 - Uterotubal carbon dioxide insufflator and accessories.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Uterotubal carbon dioxide insufflator and... Gynecological Diagnostic Devices § 884.1300 Uterotubal carbon dioxide insufflator and accessories. (a) Identification. A uterotubal carbon dioxide insufflator and accessories is a device used to test the patency...

  6. 21 CFR 888.5850 - Nonpowered orthopedic traction apparatus and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nonpowered orthopedic traction apparatus and accessories. 888.5850 Section 888.5850 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... orthopedic traction apparatus and accessories. (a) Identification. A nonpowered orthopedic traction apparatus...

  7. 21 CFR 888.5850 - Nonpowered orthopedic traction apparatus and accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Nonpowered orthopedic traction apparatus and accessories. 888.5850 Section 888.5850 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... orthopedic traction apparatus and accessories. (a) Identification. A nonpowered orthopedic traction apparatus...

  8. An Origin of Cooperative Oxygen Binding of Human Adult Hemoglobin: Different Roles of the α and β Subunits in the α2β2 Tetramer

    PubMed Central

    Sakurai, Hiroshi; Imai, Kiyohiro; Mizusawa, Naoki; Ogura, Takashi

    2015-01-01

    Human hemoglobin (Hb), which is an α2β2 tetramer and binds four O2 molecules, changes its O2-affinity from low to high as an increase of bound O2, that is characterized by ‘cooperativity’. This property is indispensable for its function of O2 transfer from a lung to tissues and is accounted for in terms of T/R quaternary structure change, assuming the presence of a strain on the Fe-histidine (His) bond in the T state caused by the formation of hydrogen bonds at the subunit interfaces. However, the difference between the α and β subunits has been neglected. To investigate the different roles of the Fe-His(F8) bonds in the α and β subunits, we investigated cavity mutant Hbs in which the Fe-His(F8) in either α or β subunits was replaced by Fe-imidazole and F8-glycine. Thus, in cavity mutant Hbs, the movement of Fe upon O2-binding is detached from the movement of the F-helix, which is supposed to play a role of communication. Recombinant Hb (rHb)(αH87G), in which only the Fe-His in the α subunits is replaced by Fe-imidazole, showed a biphasic O2-binding with no cooperativity, indicating the coexistence of two independent hemes with different O2-affinities. In contrast, rHb(βH92G), in which only the Fe-His in the β subunits is replaced by Fe-imidazole, gave a simple high-affinity O2-binding curve with no cooperativity. Resonance Raman, 1H NMR, and near-UV circular dichroism measurements revealed that the quaternary structure change did not occur upon O2-binding to rHb(αH87G), but it did partially occur with O2-binding to rHb(βH92G). The quaternary structure of rHb(αH87G) appears to be frozen in T while its tertiary structure is changeable. Thus, the absence of the Fe-His bond in the α subunit inhibits the T to R quaternary structure change upon O2-binding, but its absence in the β subunit simply enhances the O2-affinity of α subunit. PMID:26244770

  9. [Fibroadenoma in an accessory breast. A case of polythelia and fibroadenoma in the left breast region and a perivulvar accessory breast].

    PubMed

    Degrell, I

    1979-08-02

    The case of a 32-year-old female patient with multiple malformations (hare-lip, polythelia, fibroadenoma in an accessory mammary gland) and independent of these, another fibroadenoma in the breast is reported. The fibroadenoma developing in the accessory breast around the vulva, diagnosed by means of aspiration biopsy cytology, should be payed special attention. This case also confirms the applicability in preoperative diagnostics of aspiration biopsy cytology, a method which has proved to be effective for years.

  10. Identification of an inhibitory Zn2+ binding site on the human glycine receptor α1 subunit

    PubMed Central

    Harvey, Robert J; Thomas, Philip; James, Colin H; Wilderspin, Andrew; Smart, Trevor G

    1999-01-01

    Whole-cell glycine-activated currents were recorded from human embryonic kidney (HEK) cells expressing wild-type and mutant recombinant homomeric glycine receptors (GlyRs) to locate the inhibitory binding site for Zn2+ ions on the human α1 subunit. Glycine-activated currents were potentiated by low concentrations of Zn2+ (<10 μm) and inhibited by higher concentrations (>100 μm) on wild-type α1 subunit GlyRs. Lowering the external pH from 7.4 to 5.4 inhibited the glycine responses in a competitive manner. The inhibition caused by Zn2+ was abolished leaving an overt potentiating effect at 10 μm Zn2+ that was exacerbated at 100 μm Zn2+. The identification of residues involved in the formation of the inhibitory binding site was also assessed using diethylpyrocarbonate (DEPC), which modifies histidines. DEPC (1 mm) abolished Zn2+-induced inhibition and also the potentiation of glycine-activated currents by Zn2+. The reduction in glycine-induced whole-cell currents in the presence of high (100 μm) concentrations of Zn2+ did not increase the rate of glycine receptor desensitisation. Systematic mutation of extracellular histidine residues in the GlyR α1 subunit revealed that mutations H107A or H109A completely abolished inhibition of glycine-gated currents by Zn2+. However, mutation of other external histidines, H210, H215 and H419, failed to prevent inhibition by Zn2+ of glycine-gated currents. Thus, H107 and H109 in the extracellular domain of the human GlyR α1 subunit are major determinants of the inhibitory Zn2+ binding site. An examination of Zn2+ co-ordination in metalloenzymes revealed that the histidine- hydrophobic residue-histidine motif found to be responsible for binding Zn2+ in the human GlyR α1 subunit is also shared by some of these enzymes. Further comparison of the structure and location of this motif with a generic model of the GlyR α1 subunit suggests that H107 and H109 participate in the formation of the inhibitory Zn2+ binding site at the

  11. Proteomic identification of Drosophila melanogaster male accessory gland proteins, including a pro-cathepsin and a soluble gamma-glutamyl transpeptidase.

    PubMed

    Walker, Michael J; Rylett, Caroline M; Keen, Jeff N; Audsley, Neil; Sajid, Mohammed; Shirras, Alan D; Isaac, R Elwyn

    2006-05-02

    In Drosophila melanogaster, the male seminal fluid contains proteins that are important for reproductive success. Many of these proteins are synthesised by the male accessory glands and are secreted into the accessory gland lumen, where they are stored until required. Previous studies on the identification of Drosophila accessory gland products have largely focused on characterisation of male-specific accessory gland cDNAs from D. melanogaster and, more recently, Drosophila simulans. In the present study, we have used a proteomics approach without any sex bias to identify proteins in D. melanogaster accessory gland secretions. Thirteen secreted accessory gland proteins, including seven new accessory gland proteins, were identified by 2D-gel electrophoresis combined with mass spectrometry of tryptic fragments. They included protein-folding and stress-response proteins, a hormone, a lipase, a serpin, a cysteine-rich protein and two peptidases, a pro-enzyme form of a cathepsin K-like cysteine peptidase and a gamma-glutamyl transpeptidase. Enzymatic studies established that accessory gland secretions contain a cysteine peptidase zymogen that can be activated at low pH. This peptidase may have a role in the processing of female and other male-derived proteins, but is unlikely to be involved in the processing of the sex peptide. gamma-Glutamyl transpeptidases are type II integral membrane proteins; however, the identified AG gamma-glutamyl transpeptidase (GGT-1) is unusual in that it is predicted to be a soluble secreted protein, a prediction that is supported by biochemical evidence. GGT-1 is possibly involved in maintaining a protective redox environment for sperm. The strong gamma-glutamyl transpeptidase activity found in the secretions provides an explanation for the observation that glutamic acid is the most abundant free amino acid in accessory gland secretions of D. melanogaster. We have applied biochemical approaches, not used previously, to characterise

  12. The equine LH/CGβ subunit combines divergent intracellular traits of the human LHβ and CGβ subunits

    PubMed Central

    Cohen, Limor; Bousfield, George R; Ben-Menahem, David

    2017-01-01

    The pituitary LHβ and placental CGβ subunits are products of different genes in primates. The major structural difference between the two subunits is in the carboxy-terminal region, where the short carboxyl sequence of hLHβ is replaced by a longer O-glycosylated carboxy-terminal peptide (CTP) in hCGβ. In association with this structural deviation, there are marked differences in the secretion kinetics and polarized routing of the two subunits. In equids, however, the CGβ and LHβ subunits are products of the same gene expressed in the placenta and pituitary (eLH/CGβ), and both contain a CTP. This unusual expression pattern intrigued us and led to our study of eLH/CGβ subunit secretion by transfected CHO and MDCK cells. In continuous labeling and pulse chase experiments, the secretion of the eLH/CGβ subunit from the transfected CHO cells was inefficient (medium recovery of 16–25%) and slow (t1/2 >6.5 hrs). This indicated that, the secretion of the eLH/CGβ subunit resembles that of hLHβ rather than hCGβ. In MDCK cells grown on Transwell filters, the eLH/CGβ subunit was preferentially secreted from the apical side, similar to the hCGβ subunit secretory route (~65% of the total protein secreted). Taken together, these data suggested that secretion of the eLH/CGβ subunit integrates features of both hLHβ and hCGβ subunits. We propose that the evolution of this intracellular behavior may fulfill the physiological demands for biosynthesis of the eLH/CGβ subunit in the pituitary as well as in the placenta. PMID:25796287

  13. Memory in aged mice is rescued by enhanced expression of the GluN2B subunit of the NMDA receptor

    PubMed Central

    Brim, B. L.; Haskell, R.; Awedikian, R.; Ellinwood, N.M.; Jin, L.; Kumar, A.; Foster, T.C.; Magnusson, K.

    2012-01-01

    The GluN2B subunit of the N-methyl-D-aspartate (NMDA) receptor shows age-related declines in expression across the frontal cortex and hippocampus. This decline is strongly correlated to age-related memory declines. This study was designed to determine if increasing GluN2B subunit expression in the frontal lobe or hippocampus would improve memory in aged mice. Mice were injected bilaterally with either the GluN2B vector, containing cDNA specific for the GluN2B subunit and enhanced Green Fluorescent Protein (eGFP); a control vector or vehicle. Spatial memory, cognitive flexibility, and associative memory were assessed using the Morris water maze. Aged mice, with increased GluN2B subunit expression, exhibited improved long-term spatial memory, comparable to young mice. However, memory was rescued on different days in the Morris water maze; early for hippocampal GluN2B subunit enrichment and later for the frontal lobe. A higher concentration of the GluN2B antagonist, Ro 25-6981, was required to impair long-term spatial memory in aged mice with enhanced GluN2B expression, as compared to aged controls, suggesting there was an increase in the number of GluN2B-containing NMDA receptors. In addition, hippocampal slices from aged mice with increased GluN2B subunit expression exhibited enhanced NMDA receptor-mediated excitatory post-synaptic potentials (EPSP). Treatment with Ro 25-6981 showed that a greater proportion of the NMDA receptor-mediated EPSP was due to the GluN2B subunit in these animals, as compared to aged controls. These results suggest that increasing the production of the GluN2B subunit in aged animals enhances memory and synaptic transmission. Therapies that enhance GluN2B subunit expression within the aged brain may be useful for ameliorating age-related memory declines. PMID:23103326

  14. The alpha2-delta protein: an auxiliary subunit of voltage-dependent calcium channels as a recognized drug target.

    PubMed

    Thorpe, Andrew J; Offord, James

    2010-07-01

    Currently, there are two drugs on the market, gabapentin (Neurontin) and pregabalin (Lyrica), that are proposed to exert their therapeutic effect through binding to the alpha2-delta subunit of voltage-sensitive calcium channels. This activity was unexpected, as the alpha2-delta subunit had previously been considered not to be a pharmacological target. In this review, the role of the alpha2-delta subunits is discussed and the mechanism of action of the alpha2-delta ligands in vitro and in vivo is summarized. Finally, new insights into the mechanism of drugs that bind to this protein are discussed.

  15. Accessory costs of seed production and the evolution of angiosperms.

    PubMed

    Lord, Janice M; Westoby, Mark

    2012-01-01

    Accessory costs of reproduction frequently equal or exceed direct investment in offspring, and can limit the evolution of small offspring sizes. Early angiosperms had minimum seed sizes, an order of magnitude smaller than their contemporaries. It has been proposed that changes to reproductive features at the base of the angiosperm clade reduced accessory costs thus removing the fitness disadvantage of small seeds. We measured accessory costs of reproduction in 25 extant gymnosperms and angiosperms, to test whether angiosperms can produce small seeds more economically than gymnosperms. Total accessory costs scaled isometrically to seed mass for angiosperms but less than isometrically for gymnosperms, so that smaller seeds were proportionally more expensive for gymnosperms to produce. In particular, costs of abortions and packaging structures were significantly higher in gymnosperms. Also, the relationship between seed:ovule ratio and seed size was negative in angiosperms but positive in gymnosperms. We argue that the carpel was a key evolutionary innovation reducing accessory costs in angiosperms by allowing sporophytic control of pre- and postzygotic mate selection and timing of resource allocation. The resulting reduction in costs of aborting unfertilized ovules or genetically inferior embryos would have lowered total reproductive costs enabling early angiosperms to evolve small seed sizes and short generation times. © 2011 The Author(s). Evolution © 2011 The Society for the Study of Evolution.

  16. [Evaluation of iatrogenic accessory nerve injury in forensic medical practice].

    PubMed

    Somogyi, E; Irányi, J

    1996-04-14

    The authors give a survey of the clinical and medical-legal characteristics of the accessory nerve injury. In the past two decades the conception of the successfulness of the surgical treatment of the accessory nerve injury became prevailing. About the medical-legal aspects of the iatrogenic injury of the nerve reported in connection of the reconstructive surgery chiefly also departments of neurosurgery, orthopedics and traumatology. In the case of the authors a 70 year old patient suffered 10 years ago a iatrogenic accessory nerve injury. The mild trapezius palsy recovered spontaneously practically with cosmetic disadvantage. In connection with the development of extreme dorso-lumbal scoliosis associated with torsion the trapezius atrophy worsened. Physical therapy was partly successful. But the patient became unfit for manual work. Their observations sustain the data of authors who established that in the case of accessory nerve injury not only the surgical but also conservative treatment is usually successful. In opposite to certain data of the literature the authors establish that the iatrogenic injuries of the accessory nerve may lead to significant lifelong disability. The diagnosis is not always made in time with consequent delay in repair. This may be regarded as an unfavorable issue during medical-legal discussions. The authors recommend in interest to prevent nerve injury in the posterior triangle of the neck to perform operation in special department.

  17. Rhabdovirus accessory genes.

    PubMed

    Walker, Peter J; Dietzgen, Ralf G; Joubert, D Albert; Blasdell, Kim R

    2011-12-01

    The Rhabdoviridae is one of the most ecologically diverse families of RNA viruses with members infecting a wide range of organisms including placental mammals, marsupials, birds, reptiles, fish, insects and plants. The availability of complete nucleotide sequences for an increasing number of rhabdoviruses has revealed that their ecological diversity is reflected in the diversity and complexity of their genomes. The five canonical rhabdovirus structural protein genes (N, P, M, G and L) that are shared by all rhabdoviruses are overprinted, overlapped and interspersed with a multitude of novel and diverse accessory genes. Although not essential for replication in cell culture, several of these genes have been shown to have roles associated with pathogenesis and apoptosis in animals, and cell-to-cell movement in plants. Others appear to be secreted or have the characteristics of membrane-anchored glycoproteins or viroporins. However, most encode proteins of unknown function that are unrelated to any other known proteins. Understanding the roles of these accessory genes and the strategies by which rhabdoviruses use them to engage, divert and re-direct cellular processes will not only present opportunities to develop new anti-viral therapies but may also reveal aspects of cellar function that have broader significance in biology, agriculture and medicine. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

  18. Role of Plant-Specific N-Terminal Domain of Maize CK2β1 Subunit in CK2β Functions and Holoenzyme Regulation

    PubMed Central

    Vélez-Bermúdez, Isabel C.; Carretero-Paulet, Lorenzo; Lumbreras, Victoria; Pagès, Montserrat

    2011-01-01

    Protein kinase CK2 is a highly pleiotropic Ser/Thr kinase ubiquituous in eukaryotic organisms. CK2 is organized as a heterotetrameric enzyme composed of two types of subunits: the catalytic (CK2α) and the regulatory (CK2β). The CK2β subunits enhance the stability, activity and specificity of the holoenzyme, but they can also perform functions independently of the CK2 tetramer. CK2β regulatory subunits in plants differ from their animal or yeast counterparts, since they present an additional specific N-terminal extension of about 90 aminoacids that shares no homology with any previously characterized functional domain. Sequence analysis of the N-terminal domain of land plant CK2β subunit sequences reveals its arrangement through short, conserved motifs, some of them including CK2 autophosphorylation sites. By using maize CK2β1 and a deleted version (ΔNCK2β1) lacking the N-terminal domain, we have demonstrated that CK2β1 is autophosphorylated within the N-terminal domain. Moreover, the holoenzyme composed with CK2α1/ΔNCK2β1 is able to phosphorylate different substrates more efficiently than CK2α1/CK2β1 or CK2α alone. Transient overexpression of CK2β1 and ΔNCK2β1 fused to GFP in different plant systems show that the presence of N-terminal domain enhances aggregation in nuclear speckles and stabilizes the protein against proteasome degradation. Finally, bimolecular fluorescence complementation (BiFC) assays show the nuclear and cytoplasmic location of the plant CK2 holoenzyme, in contrast to the individual CK2α/β subunits mainly observed in the nucleus. All together, our results support the hypothesis that the plant-specific N-terminal domain of CK2β subunits is involved in the down-regulation of the CK2 holoenzyme activity and in the stabilization of CK2β1 protein. In summary, the whole amount of data shown in this work suggests that this domain was acquired by plants for regulatory purposes. PMID:21789193

  19. Simon Effect with and without Awareness of the Accessory Stimulus

    ERIC Educational Resources Information Center

    Treccani, Barbara; Umilta, Carlo; Tagliabue, Mariaelena

    2006-01-01

    The authors investigated whether a Simon effect could be observed in an accessory-stimulus Simon task when participants were unaware of the task-irrelevant accessory cue. In Experiment 1A a central visual target was accompanied by a suprathreshold visual lateral cue. A regular Simon effect (i.e., faster cue-response corresponding reaction times…

  20. Incorporation of DPP6a and DPP6K variants in ternary Kv4 channel complex reconstitutes properties of A-type K current in rat cerebellar granule cells.

    PubMed

    Jerng, Henry H; Pfaffinger, Paul J

    2012-01-01

    Dipeptidyl peptidase-like protein 6 (DPP6) proteins co-assemble with Kv4 channel α-subunits and Kv channel-interacting proteins (KChIPs) to form channel protein complexes underlying neuronal somatodendritic A-type potassium current (I(SA)). DPP6 proteins are expressed as N-terminal variants (DPP6a, DPP6K, DPP6S, DPP6L) that result from alternative mRNA initiation and exhibit overlapping expression patterns. Here, we study the role DPP6 variants play in shaping the functional properties of I(SA) found in cerebellar granule (CG) cells using quantitative RT-PCR and voltage-clamp recordings of whole-cell currents from reconstituted channel complexes and native I(SA) channels. Differential expression of DPP6 variants was detected in rat CG cells, with DPP6K (41 ± 3%)>DPP6a (33 ± 3%)>DPP6S (18 ± 2%)>DPP6L (8 ± 3%). To better understand how DPP6 variants shape native neuronal I(SA), we focused on studying interactions between the two dominant variants, DPP6K and DPP6a. Although previous studies did not identify unique functional effects of DPP6K, we find that the unique N-terminus of DPP6K modulates the effects of KChIP proteins, slowing recovery and producing a negative shift in the steady-state inactivation curve. By contrast, DPP6a uses its distinct N-terminus to directly confer rapid N-type inactivation independently of KChIP3a. When DPP6a and DPP6K are co-expressed in ratios similar to those found in CG cells, their distinct effects compete in modulating channel function. The more rapid inactivation from DPP6a dominates during strong depolarization; however, DPP6K produces a negative shift in the steady-state inactivation curve and introduces a slow phase of recovery from inactivation. A direct comparison to the native CG cell I(SA) shows that these mixed effects are present in the native channels. Our results support the hypothesis that the precise expression and co-assembly of different auxiliary subunit variants are important factors in shaping the I

  1. Distinct subunit contributions to the activation of M-type potassium channels by PI(4,5)P2

    PubMed Central

    Telezhkin, Vsevolod; Brown, David A.

    2012-01-01

    Low-threshold voltage-gated M-type potassium channels (M channels) are tetraheteromers, commonly of two Kv7.2 and two Kv7.3 subunits. Though gated by voltage, the channels have an absolute requirement for binding of the membrane phospholipid phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2) to open. We have investigated the quantitative relation between the concentration of a water-soluble PI(4,5)P2 analog, dioctanoyl-PI(4,5)P2 (DiC8-PI(4,5)P2), and channel open probability (Popen) by fast application of increasing concentrations of DiC8-PI(4,5)P2 to the inside face of membrane patches excised from Chinese hamster ovary cells expressing M channels as heteromeric Kv7.2/7.3 subunits. The rationale for the experiments is that this will mimic the effect of changes in membrane PI(4,5)P2 concentration. Single-channel conductances from channel current–voltage relations in cell-attached mode were 9.2 ± 0.1 pS with a 2.5-mM pipette [K+]. Plots of Popen against DiC8-PI(4,5)P2 concentration were best fitted using a two-component concentration–Popen relationship with high and low affinity, half-maximal effective concentration (EC50) values of 1.3 ± 0.14 and 75.5 ± 2.5 µM, respectively, and Hill slopes of 1.4 ± 0.06. In contrast, homomeric channels from cells expressing only Kv7.2 or Kv7.3 constructs yielded single-component curves with EC50 values of 76.2 ± 19.9 or 3.6 ± 1.0 µM, respectively. When wild-type (WT) Kv7.2 was coexpressed with a mutated Kv7.3 subunit with >100-fold reduced sensitivity to PI(4,5)P2, the high-affinity component of the activation curve was lost. Fitting the data for WT and mutant channels to an activation mechanism with independent PI(4,5)P2 binding to two Kv7.2 and two Kv7.3 subunits suggests that the two components of the M-channel activation curve correspond to the interaction of PI(4,5)P2 with the Kv7.3 and Kv7.2 subunits, respectively, that channels can open when only the two Kv7.3 subunits have bound DiC8-PI(4,5)P2, and that maximum

  2. 21 CFR 878.4400 - Electrosurgical cutting and coagulation device and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Electrosurgical cutting and coagulation device and....4400 Electrosurgical cutting and coagulation device and accessories. (a) Identification. An electrosurgical cutting and coagulation device and accessories is a device intended to remove tissue and control...

  3. The Cac2 subunit is essential for productive histone binding and nucleosome assembly in CAF-1

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Mattiroli, Francesca; Gu, Yajie; Balsbaugh, Jeremy L.

    Nucleosome assembly following DNA replication controls epigenome maintenance and genome integrity. Chromatin assembly factor 1 (CAF-1) is the histone chaperone responsible for histone (H3-H4)2 deposition following DNA synthesis. Structural and functional details for this chaperone complex and its interaction with histones are slowly emerging. Using hydrogen-deuterium exchange coupled to mass spectrometry, combined with in vitro and in vivo mutagenesis studies, we identified the regions involved in the direct interaction between the yeast CAF-1 subunits, and mapped the CAF-1 domains responsible for H3-H4 binding. The large subunit, Cac1 organizes the assembly of CAF-1. Strikingly, H3-H4 binding is mediated by a compositemore » interface, shaped by Cac1-bound Cac2 and the Cac1 acidic region. Cac2 is indispensable for productive histone binding, while deletion of Cac3 has only moderate effects on H3-H4 binding and nucleosome assembly. These results define direct structural roles for yeast CAF-1 subunits and uncover a previously unknown critical function of the middle subunit in CAF-1.« less

  4. [Clinicopathological analyses of accessory breast cancer: a report of 22 cases].

    PubMed

    Wang, Haotian; Duan, Jingjing; Xin, Fei; Cao, Xuchen

    2015-01-27

    To explore the clinicopathological characteristics, diagnosis, multi-disciplinary therapy and prognosis of accessory breast cancer. The clinical data were retrospectively analyzed for 22 patients with accessory breast cancer from December 2000 and September 2013. Three patients underwent breast-conserving local wide excision of tumor plus axillary lymph node dissection while the remainder had Auchincloss or Halsted mastectomy. The most common histological type was infiltrating ductal carcinoma (n = 16, 72%) and one of them was associated with mucous adenocarcinoma. There were carcinoma simplex (n = 1), papillary adenocarcinoma (n = 1) and adenocarcinoma (n = 4). The most common pathological stages (according to AJCC Staging of Breast Cancer, 2002, 6th edition) were II (n = 15, 68%),I(n = 3), III (n = 4) and IV (n = 0). The median follow-up period was 3 (1-14) years. And the follow-up rate was 100%.Until October 2014, 2 patients died from metastasis and the remainder survived. Accessory breast cancer is rare and has a worse prognosis.Now the clinical diagnostic criteria to it remains controversial and the diagnosis is often late. A definite diagnosis is made on the basis of clinical characteristics, postoperative pathology and imaging examinations. And surgery remains a major option.

  5. The RCN1-encoded A subunit of protein phosphatase 2A increases phosphatase activity in vivo

    NASA Technical Reports Server (NTRS)

    Deruere, J.; Jackson, K.; Garbers, C.; Soll, D.; Delong, A.; Evans, M. L. (Principal Investigator)

    1999-01-01

    Protein phosphatase 2A (PP2A), a heterotrimeric serine/threonine-specific protein phosphatase, comprises a catalytic C subunit and two distinct regulatory subunits, A and B. The RCN1 gene encodes one of three A regulatory subunits in Arabidopsis thaliana. A T-DNA insertion mutation at this locus impairs root curling, seedling organ elongation and apical hypocotyl hook formation. We have used in vivo and in vitro assays to gauge the impact of the rcn1 mutation on PP2A activity in seedlings. PP2A activity is decreased in extracts from rcn1 mutant seedlings, and this decrease is not due to a reduction in catalytic subunit expression. Roots of mutant seedlings exhibit increased sensitivity to the phosphatase inhibitors okadaic acid and cantharidin in organ elongation assays. Shoots of dark-grown, but not light-grown seedlings also show increased inhibitor sensitivity. Furthermore, cantharidin treatment of wild-type seedlings mimics the rcn1 defect in root curling, root waving and hypocotyl hook formation assays. In roots of wild-type seedlings, RCN1 mRNA is expressed at high levels in root tips, and accumulates to lower levels in the pericycle and lateral root primordia. In shoots, RCN1 is expressed in the apical hook and the basal, rapidly elongating cells in etiolated hypocotyls, and in the shoot meristem and leaf primordia of light-grown seedlings. Our results show that the wild-type RCN1-encoded A subunit functions as a positive regulator of the PP2A holoenzyme, increasing activity towards substrates involved in organ elongation and differential cell elongation responses such as root curling.

  6. Validated Competency Task Lists for Apparel and Accessories Marketing.

    ERIC Educational Resources Information Center

    Selke-Kern, Barbara E.

    Developed by a project that validated task lists by a variety of teachers and apparel marketing business persons, this guide contains task lists for occupations in the field of apparel and accessories marketing. The guide is organized in three sections. Section 1 includes the following: (1) notes on using the information in the guide; (2) a…

  7. Genetic and Physical Interactions between Tel2 and the Med15 Mediator Subunit in Saccharomyces cerevisiae

    PubMed Central

    Grandin, Nathalie; Corset, Laetitia; Charbonneau, Michel

    2012-01-01

    Background In budding yeast, the highly conserved Tel2 protein is part of several complexes and its main function is now believed to be in the biogenesis of phosphatidyl inositol 3-kinase related kinases. Principal Findings To uncover potentially novel functions of Tel2, we set out to isolate temperature-sensitive (ts) mutant alleles of TEL2 in order to perform genetic screenings. MED15/GAL11, a subunit of Mediator, a general regulator of transcription, was isolated as a suppressor of these mutants. The isolated tel2 mutants exhibited a short telomere phenotype that was partially rescued by MED15/GAL11 overexpression. The tel2-15mutant was markedly deficient in the transcription of EST2, coding for the catalytic subunit of telomerase, potentially explaining the short telomere phenotype of this mutant. In parallel, a two-hybrid screen identified an association between Tel2 and Rvb2, a highly conserved member of the AAA+ family of ATPases further found by in vivo co-immunoprecipitation to be tight and constitutive. Transiently overproduced Tel2 and Med15/Gal11 associated together, suggesting a potential role for Tel2 in transcription. Other Mediator subunits, as well as SUA7/TFIIB, also rescued the tel2-ts mutants. Significance Altogether, the present data suggest the existence of a novel role for Tel2, namely in transcription, possibly in cooperation with Rvb2 and involving the existence of physical interactions with the Med15/Gal11 Mediator subunit. PMID:22291956

  8. Finding molecular dioxygen tunnels in homoprotocatechuate 2,3-dioxygenase: implications for different reactivity of identical subunits.

    PubMed

    Xu, Liang; Zhao, Weijie; Wang, Xicheng

    2010-01-01

    Extradiol dioxygenases facilitate microbial aerobic degradation of catechol and its derivatives by activating molecular dioxygen and incorporating both oxygen atoms into their substrates. Experimental and theoretical studies have focused on the mechanism of the reaction at the active site. However, whether the catalytic rate is limited by O(2) access to the active site has not yet been explored. Here, we choose a recently solved X-ray structure of homoprotocatechuate 2,3-dioxygenase as a typical example to determine potential pathways for O(2) migration from the solvent into the enzyme center. On the basis of the trajectories of two 10-ns molecular dynamics simulations, implicit ligand sampling was used to calculate the 3D free energy map for O(2) inside the protein. The energetically optimal routes for O(2) diffusion were identified for each subunit of the homotetrameric protein structure. The O(2) tunnels formed because of thermal fluctuations were also characterized by connecting elongated cavities inside the protein. By superimposing the favorable O(2) tunnels on to the free energy map, both energetically and geometrically preferred O(2) pathways were determined, as also were the amino acids that may be critical for O(2) passage along these paths. Our results demonstrate that identical subunits possess quite distinct O(2) tunnels. The order of O(2) affinity of these tunnels is generally consistent with the order of the catalytic rate of each subunit. As a consequence, the probability of finding the reaction product is highest in the subunit containing the highest O(2) affinity pathway.

  9. Electrophysiology of Cranial Nerve Testing: Spinal Accessory and Hypoglossal Nerves.

    PubMed

    Stino, Amro M; Smith, Benn E

    2018-01-01

    Multiple techniques have been developed for the electrodiagnostic evaluation of cranial nerves XI and XII. Each of these carries both benefits and limitations, with more techniques and data being available in the literature for spinal accessory than hypoglossal nerve evaluation. Spinal accessory and hypoglossal neuropathy are relatively uncommon cranial mononeuropathies that may be evaluated in the outpatient electrodiagnostic laboratory setting. A review of available literature using PubMed was conducted regarding electrodiagnostic technique in the evaluation of spinal accessory and hypoglossal nerves searching for both routine nerve conduction studies and repetitive nerve conduction studies. The review provided herein provides a resource by which clinical neurophysiologists may develop and implement clinical and research protocols for the evaluation of both of these lower cranial nerves in the outpatient setting.

  10. E2F mediates induction of the Sp1-controlled promoter of the human DNA polymerase ɛ B-subunit gene POLE2

    PubMed Central

    Huang, Deqi; Jokela, Maarit; Tuusa, Jussi; Skog, Sven; Poikonen, Kari; Syväoja, Juhani E.

    2001-01-01

    The B-subunits of replicative DNA polymerases from Archaea to humans belong to the same protein family, suggesting that they share a common fundamental function. We report here the gene structure for the B-subunit of human DNA polymerase ɛ (POLE2), whose expression and transcriptional regulation is typical for replication proteins with some unique features. The 75 bp core promoter region, located within exon 1, contains an Sp1 element that is a critical determinant of promoter activity as shown by the luciferase reporter, electrophoretic mobility shift and DNase I footprinting assays. Two overlapping E2F elements adjacent to the Sp1 element are essential for full promoter activity and serum response. Binding sites for E2F1 and NF-1 reside immediately downstream from the core promoter region. Our results suggest that human POLE2 is regulated by two E2F–pocket protein complexes, one associated with Sp1 and the other with NF-1. So far, only one replicative DNA polymerase B-subunit gene promoter, POLA2 encoding the B-subunit of DNA polymerase α, has been characterized. Mitogenic activation of the POLE2 promoter by an E2F-mediated mechanism resembles that of POLA2, but the regulation of basal promoter activity is different between these two genes. PMID:11433027

  11. Transcriptional activation of melanocortin 2 receptor accessory protein by PPARγ in adipocytes

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kim, Nam Soo; Kim, Yoon-Jin; Cho, Si Young

    2013-09-27

    Highlights: •MRAP enhanced HSL expression. •ACTH-mediated MRAP reduced glycerol release. •PPARγ induced MRAP expression. •PPARγ bound to the MRAP promoter. -- Abstract: Adrenocorticotropic hormone (ACTH) in rodents decreases lipid accumulation and body weight. Melanocortin receptor 2 (MC2R) and MC2R accessory protein (MRAP) are specific receptors for ACTH in adipocytes. Peroxisome proliferator-activated receptor γ (PPARγ) plays a role in the transcriptional regulation of metabolic pathways such as adipogenesis and β-oxidation of fatty acids. In this study we investigated the transcriptional regulation of MRAP expression during differentiation of 3T3-L1 cells. Stimulation with ACTH affected lipolysis in murine mature adipocytes via MRAP. Putativemore » peroxisome proliferator response element (PPRE) was identified in the MRAP promoter region. In chromatin immunoprecipitation and reporter assays, we observed binding of PPARγ to the MRAP promoter. The mutagenesis experiments showed that the −1209/−1198 region of the MRAP promoter could function as a PPRE site. These results suggest that PPARγ is required for transcriptional activation of the MRAP gene during adipogenesis, which contributes to understanding of the molecular mechanism of lipolysis in adipocytes.« less

  12. Accessory papillary muscles and papillary muscle hypertrophy are associated with sudden cardiac arrest of unknown cause.

    PubMed

    Uhm, Jae-Sun; Youn, Jong-Chan; Lee, Hye-Jeong; Park, Junbeom; Park, Jin-Kyu; Shim, Chi Young; Hong, Geu-Ru; Joung, Boyoung; Pak, Hui-Nam; Lee, Moon-Hyoung

    2015-10-15

    The present study was performed for elucidating the associations between the morphology of the papillary muscles (PMs) and sudden cardiac arrest (SCA). We retrospectively reviewed history, laboratory data, electrocardiography, echocardiography, coronary angiography, and cardiac CT/MRI for 190 patients with SCA. The prevalence of accessory PMs and PM hypertrophy in patients with SCA of unknown cause was compared with that in patients with SCA of known causes and 98 age- and sex-matched patients without SCA. An accessory PM was defined as a PM with origins separated from the anterolateral and posteromedial PMs, or a PM that branched into two or three bellies at the base of the anterolateral or posteromedial PM. PM hypertrophy was defined as at least one of the two PMs having a diameter of ≥1.1cm. In 49 patients (age 49.9±15.9years; 38 men) the cause of SCA was unknown, whereas 141 (age 54.2±16.6years; 121 men) had a known cause. The prevalence of accessory PMs was significantly higher in the unknown-cause group than in the known-cause group (24.5% and 7.8%, respectively; p=0.002) or the no-SCA group (7.1%, p=0.003). The same was true for PM hypertrophy (unknown-cause 12.2%, known-cause 2.1%, p=0.010; no SCA group 1.0%, p=0.006). By logistic regression, accessory PM and PM hypertrophy were independently associated with sudden cardiac arrest of unknown cause. An accessory PM and PM hypertrophy are associated with SCA of unknown cause. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  13. Teaching Techniques for Accessory Percussion

    ERIC Educational Resources Information Center

    Micallef, Ken

    2007-01-01

    Everyone is familiar with the main percussion instruments of the contemporary orchestra: bass drum, snare drum, suspended cymbal, vibraphone, and timpani. But as source material broadens, so do the demands placed on the percussion section. Accessory, or auxiliary percussion, can make the difference between a typical rendition of a well-known piece…

  14. Immunocytochemical localization of the NMDA-R2A receptor subunit in the cat retina.

    PubMed

    Goebel, D J; Aurelia, J L; Tai, Q; Jojich, L; Poosch, M S

    1998-10-19

    Immunocytochemical studies were performed to determine the distribution and cellular localization of the NMDA-R2A receptor subunit (R2A) in the cat retina. R2A-immunoreactivity (R2A-IR) was noted in all layers of the retina, with specific localizations in the outer segments of red/green and blue cone photoreceptors, B-type horizontal cells, several types of amacrine cells, Müller cells and the majority of cells in the ganglion cell layer. In the inner nuclear layer, 48% of all cells residing in the amacrine cell layer were R2A-IR including a cell resembling the GABAergic A17 amacrine cell. Interestingly, the AII rod amacrine cell was devoid of R2A-IR. Although the localization of the R2A subunit was anticipated in ganglion cells, amacrines and Müller cells, the presence of this receptor subunit to the cells in the outer retina was not expected. Here, both the R2A and the R2B subunits were found to be present in the outer segments of cone photoreceptors and to the tips of rod outer segments. Although the function of these receptor subunits in rod and cone photoreceptors remains to be determined, the fact that both R2A and R2B receptor subunits are localized to cone outer segments suggests a possible alternative pathway for calcium entry into a region where this cation plays such a crucial role in the process of phototransduction. To further classify the cells that display NR2A-IR, we performed dual labeling experiments showing the relationship between R2A-labeled cells with GABA. Results showed that all GABAergic-amacrines and displaced amacrines express the R2A-subunit protein. In addition, approximately 11% of the NR2A-labeled amacrines, did not stain for GABA. These findings support pharmacological data showing that NMDA directly facilitates GABA release in retina and retinal cultures [I.L. Ferreira, C.B. Duarte, P.F. Santos, C.M. Carvalho, A.P. Carvalho, Release of [3H]GABA evoked by glutamate receptor agonist in cultured chick retinal cells: effect of Ca2

  15. Accessory renal arteries: Prevalence in resistant hypertension and an important role in nonresponse to radiofrequency renal denervation.

    PubMed

    VonAchen, Paige; Hamann, Jason; Houghland, Thomas; Lesser, John R; Wang, Yale; Caye, David; Rosenthal, Kristi; Garberich, Ross F; Daniels, Mary; Schwartz, Robert S

    The aim of this study was to understand the role of accessory renal arteries in resistant hypertension, and to establish their role in nonresponse to radiofrequency renal denervation (RDN) procedures. Prior studies suggest a role for accessory renal arteries in hypertensive syndromes, and recent clinical trials of renal denervation report that these anomalies are highly prevalent in resistant hypertension. This study evaluated the relationships among resistant hypertension, accessory renal arteries, and the response to radiofrequency (RF) renal denervation. Computed Tomography Angiography (CTA) and magnetic resonance imaging (MRI) scans from 58 patients with resistant hypertension undergoing RF renal denervation (RDN) were evaluated. Results were compared with CT scans in 57 healthy, normotensive subjects undergoing screening as possible renal transplant donors. All scans were carefully studied for accessory renal arteries, and were correlated with long term blood pressure reduction. Accessory renal arteries were markedly more prevalent in the hypertensive patients than normotensive renal donors (59% vs 32% respectively, p=0.004). RDN had an overall nonresponse rate of 29% (response rate 71%). Patients without accessory vessels had a borderline higher response rate to RDN than those with at least one accessory vessel (83% vs 62% respectively, p=0.076) and a higher RDN response than patients with untreated accessory arteries (83% vs 55%; p=0.040). For accessory renal arteries and nonresponse, the sensitivity was 76%, specificity 49%, with positive and negative predictive values 38% and 83% respectively. Accessory renal arteries were markedly over-represented in resistant hypertensives compared with healthy controls. While not all patients with accessory arteries were nonresponders, nonresponse was related to both the presence and non-treatment of accessory arteries. Addressing accessory renal arteries in future clinical trials may improve RDN therapeutic efficacy

  16. Domain Architecture of the Catalytic Subunit in the ISW2-Nucleosome Complex▿

    PubMed Central

    Dang, Weiwei; Bartholomew, Blaine

    2007-01-01

    ATP-dependent chromatin remodeling has an important role in the regulation of cellular differentiation and development. For the first time, a topological view of one of these complexes has been revealed, by mapping the interactions of the catalytic subunit Isw2 with nucleosomal and extranucleosomal DNA in the complex with all four subunits of ISW2 bound to nucleosomes. Different domains of Isw2 were shown to interact with the nucleosome near the dyad axis, another near the entry site of the nucleosome, and another with extranucleosomal DNA. The conserved DEXD or ATPase domain was found to contact the superhelical location 2 (SHL2) of the nucleosome, providing a direct physical connection of ATP hydrolysis with this region of nucleosomes. The C terminus of Isw2, comprising the SLIDE (SANT-like domain) and HAND domains, was found to be associated with extranucleosomal DNA and the entry site of nucleosomes. It is thus proposed that the C-terminal domains of Isw2 are involved in anchoring the complex to nucleosomes through their interactions with linker DNA and that they facilitate the movement of DNA along the surface of nucleosomes. PMID:17908792

  17. Mlh2 Is an Accessory Factor for DNA Mismatch Repair in Saccharomyces cerevisiae

    PubMed Central

    Srivatsan, Anjana; Bowen, Nikki; Gries, Kerstin; Desai, Arshad; Putnam, Christopher D.; Kolodner, Richard D.

    2014-01-01

    In Saccharomyces cerevisiae, the essential mismatch repair (MMR) endonuclease Mlh1-Pms1 forms foci promoted by Msh2-Msh6 or Msh2-Msh3 in response to mispaired bases. Here we analyzed the Mlh1-Mlh2 complex, whose role in MMR has been unclear. Mlh1-Mlh2 formed foci that often colocalized with and had a longer lifetime than Mlh1-Pms1 foci. Mlh1-Mlh2 foci were similar to Mlh1-Pms1 foci: they required mispair recognition by Msh2-Msh6, increased in response to increased mispairs or downstream defects in MMR, and formed after induction of DNA damage by phleomycin but not double-stranded breaks by I-SceI. Mlh1-Mlh2 could be recruited to mispair-containing DNA in vitro by either Msh2-Msh6 or Msh2-Msh3. Deletion of MLH2 caused a synergistic increase in mutation rate in combination with deletion of MSH6 or reduced expression of Pms1. Phylogenetic analysis demonstrated that the S. cerevisiae Mlh2 protein and the mammalian PMS1 protein are homologs. These results support a hypothesis that Mlh1-Mlh2 is a non-essential accessory factor that acts to enhance the activity of Mlh1-Pms1. PMID:24811092

  18. Decontamination of minimally invasive surgical endoscopes and accessories.

    PubMed

    Ayliffe, G

    2000-08-01

    (1) Infections following invasive endoscopy are rare and are usually of endogenous origin. Nevertheless, infections do occur due to inadequate cleaning and disinfection and the use of contaminated rinse water and processing equipment. (2) Rigid and flexible operative endoscopes and accessories should be thoroughly cleaned and preferably sterilized using properly validated processes. (3) Heat tolerant operative endoscopes and accessories should be sterilized using a vacuum assisted steam sterilizer. Use autoclavable instrument trays or containers to protect equipment during transit and processing. Small bench top sterilizers without vacuum assisted air removal are unsuitable for packaged and lumened devices. (4) Heat sensitive rigid and flexible endoscopes and accessories should preferably be sterilized using ethylene oxide, low temperature steam and formaldehyde (rigid only) or gas plasma (if appropriate). (5) If there are insufficient instruments or time to sterilize invasive endoscopes, or if no suitable method is available locally, they may be disinfected by immersion in 2% glutaraldehyde or a suitable alternative. An immersion time of at least 10 min should be adopted for glutaraldehyde. This is sufficient to inactivate most vegetative bacteria and viruses including HIV and hepatitis B virus (HBV). Longer contact times of 20 min or more may be necessary if a mycobacterial infection is known or suspected. At least 3 h immersion in glutaraldehyde is required to kill spores. (6) Glutaraldehyde is irritant and sensitizing to the skin, eyes and respiratory tract. Measures must be taken to ensure glutaraldehyde is used in a safe manner, i.e., total containment and/or extraction of harmful vapour and the provision of suitable personal protective equipment, i.e., gloves, apron and eye protection if splashing could occur. Health surveillance of staff is recommended and should include a pre-employment enquiry regarding asthma, skin and mucosal sensitivity problems and

  19. Effect of tyrphostin AG879 on Kv4.2 and Kv4.3 potassium channels

    PubMed Central

    Yu, Haibo; Zou, Beiyan; Wang, Xiaoliang; Li, Min

    2015-01-01

    Background and Purpose A-type potassium channels (IA) are important proteins for modulating neuronal membrane excitability. The expression and activity of Kv4.2 channels are critical for neurological functions and pharmacological inhibitors of Kv4.2 channels may have therapeutic potential for Fragile X syndrome. While screening various compounds, we identified tyrphostin AG879, a tyrosine kinase inhibitor, as a Kv4.2 inhibitor from. In the present study we characterized the effect of AG879 on cloned Kv4.2/Kv channel-interacting protein 2 (KChIP2) channels. Experimental Approach To screen the library of pharmacologically active compounds, the thallium flux assay was performed on HEK-293 cells transiently-transfected with Kv4.2 cDNA using the Maxcyte transfection system. The effects of AG879 were further examined on CHO-K1 cells expressing Kv4.2/KChIP2 channels using a whole-cell patch-clamp technique. Key Results Tyrphostin AG879 selectively and dose-dependently inhibited Kv4.2 and Kv4.3 channels. In Kv4.2/KChIP2 channels, AG879 induced prominent acceleration of the inactivation rate, use-dependent block and slowed the recovery from inactivation. AG879 induced a hyperpolarizing shift in the voltage-dependence of the steady-state inactivation of Kv4.2 channels without apparent effect on the V1/2 of the voltage-dependent activation. The blocking effect of AG879 was enhanced as channel inactivation increased. Furthermore, AG879 significantly inhibited the A-type potassium currents in the cultured hippocampus neurons. Conclusion and Implications AG879 was identified as a selective and potent inhibitor the Kv4.2 channel. AG879 inhibited Kv4.2 channels by preferentially interacting with the open state and further accelerating their inactivation. PMID:25752739

  20. Effect of tyrphostin AG879 on Kv 4.2 and Kv 4.3 potassium channels.

    PubMed

    Yu, Haibo; Zou, Beiyan; Wang, Xiaoliang; Li, Min

    2015-07-01

    A-type potassium channels (IA) are important proteins for modulating neuronal membrane excitability. The expression and activity of Kv 4.2 channels are critical for neurological functions and pharmacological inhibitors of Kv 4.2 channels may have therapeutic potential for Fragile X syndrome. While screening various compounds, we identified tyrphostin AG879, a tyrosine kinase inhibitor, as a Kv 4.2 inhibitor from. In the present study we characterized the effect of AG879 on cloned Kv 4.2/Kv channel-interacting protein 2 (KChIP2) channels. To screen the library of pharmacologically active compounds, the thallium flux assay was performed on HEK-293 cells transiently-transfected with Kv 4.2 cDNA using the Maxcyte transfection system. The effects of AG879 were further examined on CHO-K1 cells expressing Kv 4.2/KChIP2 channels using a whole-cell patch-clamp technique. Tyrphostin AG879 selectively and dose-dependently inhibited Kv 4.2 and Kv 4.3 channels. In Kv 4.2/KChIP2 channels, AG879 induced prominent acceleration of the inactivation rate, use-dependent block and slowed the recovery from inactivation. AG879 induced a hyperpolarizing shift in the voltage-dependence of the steady-state inactivation of Kv 4.2 channels without apparent effect on the V1/2 of the voltage-dependent activation. The blocking effect of AG879 was enhanced as channel inactivation increased. Furthermore, AG879 significantly inhibited the A-type potassium currents in the cultured hippocampus neurons. AG879 was identified as a selective and potent inhibitor the Kv 4.2 channel. AG879 inhibited Kv 4.2 channels by preferentially interacting with the open state and further accelerating their inactivation. © 2015 The British Pharmacological Society.

  1. Persistent Increase in Blood Pressure After Renal Nerve Stimulation in Accessory Renal Arteries After Sympathetic Renal Denervation.

    PubMed

    de Jong, Mark R; Hoogerwaard, Annemiek F; Gal, Pim; Adiyaman, Ahmet; Smit, Jaap Jan J; Delnoy, Peter Paul H M; Ramdat Misier, Anand R; van Hasselt, Boudewijn A A M; Heeg, Jan-Evert; le Polain de Waroux, Jean-Benoit; Lau, Elizabeth O Y; Staessen, Jan A; Persu, Alexandre; Elvan, Arif

    2016-06-01

    Blood pressure response to renal denervation is highly variable, and the proportion of responders is disappointing. This may be partly because of accessory renal arteries too small for denervation, causing incomplete ablation. Renal nerve stimulation before and after renal denervation is a promising approach to assess completeness of renal denervation and may predict blood pressure response to renal denervation. The objective of the current study was to assess renal nerve stimulation-induced blood pressure increase before and after renal sympathetic denervation in main and accessory renal arteries of anaesthetized patients with drug-resistant hypertension. The study included 21 patients. Nine patients had at least 1 accessory renal artery in which renal denervation was not feasible. Renal nerve stimulation was performed in the main arteries of all patients and in accessory renal arteries of 6 of 9 patients with accessory arteries, both before and after renal sympathetic denervation. Renal nerve stimulation before renal denervation elicited a substantial increase in systolic blood pressure, both in main (25.6±2.9 mm Hg; P<0.001) and accessory (24.3±7.4 mm Hg; P=0.047) renal arteries. After renal denervation, renal nerve stimulation-induced systolic blood pressure increase was blunted in the main renal arteries (Δ systolic blood pressure, 8.6±3.7 mm Hg; P=0.020), but not in the nondenervated renal accessory renal arteries (Δ systolic blood pressure, 27.1±7.6 mm Hg; P=0.917). This residual source of renal sympathetic tone may result in persistent hypertension after ablation and partly account for the large response variability. © 2016 American Heart Association, Inc.

  2. Role of the Accessory Parotid Gland in the Etiology of Parotitis: Statistical Analysis of Sialographic Features

    PubMed Central

    Zhu, Wangyong; Hu, Fengchun; Liu, Xingguang; Guo, Songcan; Tao, Qian

    2016-01-01

    This retrospective study aimed to identify if the existence of the accessory parotid gland correlated with the etiology of parotitis. This may aid the development of better treatment strategies in the future. Sialographic features of cases with parotitis and healthy subjects were reviewed. The chi-square test was used to compare the incidence of accessory parotid gland between the groups. The Student’s t test was used to compare the length of Stensen’s duct, the length from the orifice to the confluence of the accessory duct, and the angle between the accessory duct and Stensen’s duct between the groups. The incidence of accessory parotid gland in patients with parotitis was 71.8% (28/39), which was significantly higher than that in healthy subjects (P = 0.005). Patients with parotitis had a longer Stensen’s duct than healthy subjects (P = 0.003). There was no significant difference in the length from the orifice to the confluence of the accessory duct or the angle between the accessory duct and Stensen’s duct (P = 0.136 and 0.511, respectively) between the groups. The accessory parotid gland might play a role in the pathogenesis of parotitis. The existence of an accessory parotid gland is likely to interfere with salivary flow. Computational fluid dynamics analysis of salivary flow in the ductal system would be useful in future etiologic studies on parotitis. PMID:26913509

  3. Role of the Accessory Parotid Gland in the Etiology of Parotitis: Statistical Analysis of Sialographic Features.

    PubMed

    Zhu, Wangyong; Hu, Fengchun; Liu, Xingguang; Guo, Songcan; Tao, Qian

    2016-01-01

    This retrospective study aimed to identify if the existence of the accessory parotid gland correlated with the etiology of parotitis. This may aid the development of better treatment strategies in the future. Sialographic features of cases with parotitis and healthy subjects were reviewed. The chi-square test was used to compare the incidence of accessory parotid gland between the groups. The Student's t test was used to compare the length of Stensen's duct, the length from the orifice to the confluence of the accessory duct, and the angle between the accessory duct and Stensen's duct between the groups. The incidence of accessory parotid gland in patients with parotitis was 71.8% (28/39), which was significantly higher than that in healthy subjects (P = 0.005). Patients with parotitis had a longer Stensen's duct than healthy subjects (P = 0.003). There was no significant difference in the length from the orifice to the confluence of the accessory duct or the angle between the accessory duct and Stensen's duct (P = 0.136 and 0.511, respectively) between the groups. The accessory parotid gland might play a role in the pathogenesis of parotitis. The existence of an accessory parotid gland is likely to interfere with salivary flow. Computational fluid dynamics analysis of salivary flow in the ductal system would be useful in future etiologic studies on parotitis.

  4. Phosphorylation sites in the Hook domain of CaVβ subunits differentially modulate CaV1.2 channel function.

    PubMed

    Brunet, Sylvain; Emrick, Michelle A; Sadilek, Martin; Scheuer, Todd; Catterall, William A

    2015-10-01

    Regulation of L-type calcium current is critical for the development, function, and regulation of many cell types. Ca(V)1.2 channels that conduct L-type calcium currents are regulated by many protein kinases, but the sites of action of these kinases remain unknown in most cases. We combined mass spectrometry (LC-MS/MS) and whole-cell patch clamp techniques in order to identify sites of phosphorylation of Ca(V)β subunits in vivo and test the impact of mutations of those sites on Ca(V)1.2 channel function in vitro. Using the Ca(V)1.1 channel purified from rabbit skeletal muscle as a substrate for phosphoproteomic analysis, we found that Ser(193) and Thr(205) in the HOOK domain of Ca(V)β1a subunits were both phosphorylated in vivo. Ser(193) is located in a potential consensus sequence for casein kinase II, but it was not phosphorylated in vitro by that kinase. In contrast, Thr(205) is located in a consensus sequence for cAMP-dependent phosphorylation, and it was robustly phosphorylated in vitro by PKA. These two sites are conserved in multiple Ca(V)β subunit isoforms, including the principal Ca(V)β subunit of cardiac Ca(V)1.2 channels, Ca(V)β2b. In order to assess potential modulatory effects of phosphorylation at these sites separately from the effects of phosphorylation of the α11.2 subunit, we inserted phosphomimetic or phosphoinhibitory mutations in Ca(V)β2b and analyzed their effects on Ca(V)1.2 channel function in transfected nonmuscle cells. The phosphomimetic mutation Ca(V)β2b(S152E) decreased peak channel currents and shifted the voltage dependence of both activation and inactivation to more positive membrane potentials. The phosphoinhibitory mutation Ca(V)β2b(S152A) had opposite effects. There were no differences in peak Ca(V)1.2 currents or voltage dependence between the phosphomimetic mutation Ca(V)β2b(T164D) and the phosphoinhibitory mutation Ca(V)β2b(T164A). However, calcium-dependent inactivation was significantly increased for the

  5. Diversity in genomic organisation, developmental regulation and distribution of the murine PR72/B" subunits of protein phosphatase 2A

    PubMed Central

    Zwaenepoel, Karen; Louis, Justin V; Goris, Jozef; Janssens, Veerle

    2008-01-01

    Background Protein phosphatase 2A (PP2A) is a serine/threonine-specific phosphatase displaying vital functions in growth and development through its role in various signalling pathways. PP2A holoenzymes comprise a core dimer composed of a catalytic C and a structural A subunit, which can associate with a variable B-type subunit. The importance of the B-type subunits for PP2A regulation cannot be overestimated as they determine holoenzyme localisation, activity and substrate specificity. Three B-type subunit families have been identified: PR55/B, PR61/B' and PR72/B", of which the latter is currently the least characterised. Results We deduced the sequences and genomic organisation of the different murine PR72/B" isoforms: three genes encode nine isoforms, five of which are abundantly expressed and give rise to genuine PP2A subunits. Thereby, one novel subunit was identified. Using Northern blotting, we examined the tissue-specific and developmental expression of these subunits. All subunits are highly expressed in heart, suggesting an important cardiac function. Immunohistochemical analysis revealed a striated expression pattern of PR72 and PR130 in heart and skeletal muscle, but not in bladder smooth muscle. The subcellular localisation and cell cycle regulatory ability of several PR72/B" isoforms were determined, demonstrating differences as well as similarities. Conclusion In contrast to PR55/B and PR61/B', the PR72/B" family seems evolutionary more divergent, as only two of the murine genes have a human orthologue. We have integrated these results in a more consistent nomenclature of both human and murine PR72/B" genes and their transcripts/proteins. Our results provide a platform for the future generation of PR72/B" knockout mice. PMID:18715506

  6. Accessory enzymes influence cellulase hydrolysis of the model substrate and the realistic lignocellulosic biomass.

    PubMed

    Sun, Fubao Fuebiol; Hong, Jiapeng; Hu, Jinguang; Saddler, Jack N; Fang, Xu; Zhang, Zhenyu; Shen, Song

    2015-11-01

    The potential of cellulase enzymes in the developing and ongoing "biorefinery" industry has provided a great motivation to develop an efficient cellulase mixture. Recent work has shown how important the role that the so-called accessory enzymes can play in an effective enzymatic hydrolysis. In this study, three newest Novozymes Cellic CTec cellulase preparations (CTec 1/2/3) were compared to hydrolyze steam pretreated lignocellulosic substrates and model substances at an identical FPA loading. These cellulase preparations were found to display significantly different hydrolytic performances irrelevant with the FPA. And this difference was even observed on the filter paper itself when the FPA based assay was revisited. The analysis of specific enzyme activity in cellulase preparations demonstrated that different accessory enzymes were mainly responsible for the discrepancy of enzymatic hydrolysis between diversified substrates and various cellulases. Such the active role of accessory enzymes present in cellulase preparations was finally verified by supplementation with β-glucosidase, xylanase and lytic polysaccharide monooxygenases AA9. This paper provides new insights into the role of accessory enzymes, which can further provide a useful reference for the rational customization of cellulase cocktails in order to realize an efficient conversion of natural lignocellulosic substrates. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. LRP1 influences trafficking of N-type calcium channels via interaction with the auxiliary α2δ-1 subunit

    PubMed Central

    Kadurin, Ivan; Rothwell, Simon W.; Lana, Beatrice; Nieto-Rostro, Manuela; Dolphin, Annette C.

    2017-01-01

    Voltage-gated Ca2+ (CaV) channels consist of a pore-forming α1 subunit, which determines the main functional and pharmacological attributes of the channel. The CaV1 and CaV2 channels are associated with auxiliary β- and α2δ-subunits. The molecular mechanisms involved in α2δ subunit trafficking, and the effect of α2δ subunits on trafficking calcium channel complexes remain poorly understood. Here we show that α2δ-1 is a ligand for the Low Density Lipoprotein (LDL) Receptor-related Protein-1 (LRP1), a multifunctional receptor which mediates trafficking of cargoes. This interaction with LRP1 is direct, and is modulated by the LRP chaperone, Receptor-Associated Protein (RAP). LRP1 regulates α2δ binding to gabapentin, and influences calcium channel trafficking and function. Whereas LRP1 alone reduces α2δ-1 trafficking to the cell-surface, the LRP1/RAP combination enhances mature glycosylation, proteolytic processing and cell-surface expression of α2δ-1, and also increase plasma-membrane expression and function of CaV2.2 when co-expressed with α2δ-1. Furthermore RAP alone produced a small increase in cell-surface expression of CaV2.2, α2δ-1 and the associated calcium currents. It is likely to be interacting with an endogenous member of the LDL receptor family to have these effects. Our findings now provide a key insight and new tools to investigate the trafficking of calcium channel α2δ subunits. PMID:28256585

  8. An Accessory Muscle of Pectoral Region: A Case Report

    PubMed Central

    Bannur, B.M.; Mallashetty, Nagaraj; Endigeri, Preetish

    2013-01-01

    Among the variations of pectoral muscles, this case appears to be unique in the literature. This was a case of an accessory pectoral muscle which was located between pectoralis major and pectoralis minor muscles, which was discovered during a routine anatomy dissection. The accessory muscle originated from 6th and 7th ribs at costo-chondral junction, which travelled supero-laterally and inserted by fusing with fibres of pectoralis minor. This unusual muscle holds importance for surgeons while they perform dissectomies, in avoiding complications. PMID:24179919

  9. Accessory Navicular Syndrome in Athlete vs General Population.

    PubMed

    Jegal, Hyuk; Park, Young Uk; Kim, Jin Su; Choo, Ho Sik; Seo, Young Uk; Lee, Kyung Tai

    2016-08-01

    Symptomatic accessory navicular syndrome (ANS) typically develops in young athletes. The symptoms are exacerbated during exercise or while walking, affecting the sports performance of athletes. The purpose of this study was to evaluate the radiologic findings and clinical course in athletes with accessory navicular syndrome (ANS) in comparison with a nonathletic population. Seventy-nine patients with ANS between August 2012 and August 2013 were included. Overall, 29 were athletes and 50 were not athletes, and 19 (2 athletes and 17 nonathletes) of them improved after at least 6 months of conservative treatment. The records of 60 patients (64 consecutive feet) of ANS treated by modified Kidner operation were evaluated retrospectively. The study population included 27 athletes (31 feet) and 33 nonathletes (33 feet). Clinical features and radiologic findings were compared between them. Overall, 34% of the nonathletes improved after conservative treatment, but only 6.9% of athletes improved (P < .001). Mean age at surgery in the athlete group was 16.1 years (range, 12-26), and 24.3 years (range, 12-52) in the nonathlete group (P < .001). There was a history of trauma in 23 feet (74%) of the athlete group and in 13 feet (39%) of the nonathlete group (P = .006). Eighteen feet (58%) in the athlete group and 11 feet (32%) in the nonathlete group showed movement between the 2 bones (P = .047). Bone marrow edema was observed in both navicular and accessory navicular in all of the athletes (27/27, 100%). But it was only present in 80% (16/20) for nonathletes (P = .012). The radiologic findings and clinical course of athletes were different from that of the general population. Their symptoms were more refractory to conservative treatment than the nonathletes group. Therefore, early operative treatment could be considered in cases of symptomatic ANS especially for athletes. Level III, retrospective comparative case series. © The Author(s) 2016.

  10. Headgear Accessories Classification Using an Overhead Depth Sensor

    PubMed Central

    Luna, Carlos A.; Marron-Romera, Marta; Mazo, Manuel; Luengo-Sanchez, Sara; Macho-Pedroso, Roberto

    2017-01-01

    In this paper, we address the generation of semantic labels describing the headgear accessories carried out by people in a scene under surveillance, only using depth information obtained from a Time-of-Flight (ToF) camera placed in an overhead position. We propose a new method for headgear accessories classification based on the design of a robust processing strategy that includes the estimation of a meaningful feature vector that provides the relevant information about the people’s head and shoulder areas. This paper includes a detailed description of the proposed algorithmic approach, and the results obtained in tests with persons with and without headgear accessories, and with different types of hats and caps. In order to evaluate the proposal, a wide experimental validation has been carried out on a fully labeled database (that has been made available to the scientific community), including a broad variety of people and headgear accessories. For the validation, three different levels of detail have been defined, considering a different number of classes: the first level only includes two classes (hat/cap, and no hat/cap), the second one considers three classes (hat, cap and no hat/cap), and the last one includes the full class set with the five classes (no hat/cap, cap, small size hat, medium size hat, and large size hat). The achieved performance is satisfactory in every case: the average classification rates for the first level reaches 95.25%, for the second one is 92.34%, and for the full class set equals 84.60%. In addition, the online stage processing time is 5.75 ms per frame in a standard PC, thus allowing for real-time operation. PMID:28796177

  11. Structure of the Cmr2 Subunit of the CRISPR-Cas RNA Silencing Complex

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cocozaki, Alexis I.; Ramia, Nancy F.; Shao, Yaming

    Cmr2 is the largest and an essential subunit of a CRISPR RNA-Cas protein complex (the Cmr complex) that cleaves foreign RNA to protect prokaryotes from invading genetic elements. Cmr2 is thought to be the catalytic subunit of the effector complex because of its N-terminal HD nuclease domain. Here, however, we report that the HD domain of Cmr2 is not required for cleavage by the complex in vitro. The 2.3 {angstrom} crystal structure of Pyrococcus furiosus Cmr2 (lacking the HD domain) reveals two adenylyl cyclase-like and two {alpha}-helical domains. The adenylyl cyclase-like domains are arranged as in homodimeric adenylyl cyclases andmore » bind ADP and divalent metals. However, mutagenesis studies show that the metal- and ADP-coordinating residues of Cmr2 are also not critical for cleavage by the complex. Our findings suggest that another component provides the catalytic function and that the essential role by Cmr2 does not require the identified ADP- or metal-binding or HD domains in vitro.« less

  12. 21 CFR 884.1720 - Gynecologic laparoscope and accessories.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... accessory instruments include: the lens cleaning brush, biopsy brush, clip applier (without clips...), retractor, mechanical (noninflatable), snare, stylet, forceps, dissector, mechanical (noninflatable...

  13. 21 CFR 884.1720 - Gynecologic laparoscope and accessories.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... accessory instruments include: the lens cleaning brush, biopsy brush, clip applier (without clips...), retractor, mechanical (noninflatable), snare, stylet, forceps, dissector, mechanical (noninflatable...

  14. 21 CFR 884.1720 - Gynecologic laparoscope and accessories.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... accessory instruments include: the lens cleaning brush, biopsy brush, clip applier (without clips...), retractor, mechanical (noninflatable), snare, stylet, forceps, dissector, mechanical (noninflatable...

  15. Proton modulation of recombinant GABAA receptors: influence of GABA concentration and the β subunit TM2–TM3 domain

    PubMed Central

    Wilkins, Megan E; Hosie, Alastair M; Smart, Trevor G

    2005-01-01

    Regulation of GABAA receptors by extracellular pH exhibits a dependence on the receptor subunit composition. To date, the molecular mechanism responsible for the modulation of GABAA receptors at alkaline pH has remained elusive. We report here that the GABA-activated current can be potentiated at pH 8.4 for both αβ and αβγ subunit-containing receptors, but only at GABA concentrations below the EC40. Site-specific mutagenesis revealed that a single lysine residue, K279 in the β subunit TM2–TM3 linker, was critically important for alkaline pH to modulate the function of both α1β2 and α1β2γ2 receptors. The ability of low concentrations of GABA to reveal different pH titration profiles for GABAA receptors was also examined at acidic pH. At pH 6.4, GABA activation of αβγ receptors was enhanced at low GABA concentrations. This effect was ablated by the mutation H267A in the β subunit. Decreasing the pH further to 5.4 inhibited GABA responses via αβγ receptors, whereas those responses recorded from αβ receptors were potentiated. Inserting homologous β subunit residues into the γ2 subunit to recreate, in αβγ receptors, the proton modulatory profile of αβ receptors, established that in the presence of β2H267, the mutation γ2T294K was necessary to potentiate the GABA response at pH 5.4. This residue, T294, is homologous to K279 in the β subunit and suggests that a lysine at this position is an important residue for mediating the allosteric effects of both acidic and alkaline pH changes, rather than forming a direct site for protonation within the GABAA receptor. PMID:15946973

  16. Calcium Currents Are Enhanced by α2δ-1 Lacking Its Membrane Anchor*

    PubMed Central

    Kadurin, Ivan; Alvarez-Laviada, Anita; Ng, Shu Fun Josephine; Walker-Gray, Ryan; D'Arco, Marianna; Fadel, Michael G.; Pratt, Wendy S.; Dolphin, Annette C.

    2012-01-01

    The accessory α2δ subunits of voltage-gated calcium channels are membrane-anchored proteins, which are highly glycosylated, possess multiple disulfide bonds, and are post-translationally cleaved into α2 and δ. All α2δ subunits have a C-terminal hydrophobic, potentially trans-membrane domain and were described as type I transmembrane proteins, but we found evidence that they can be glycosylphosphatidylinositol-anchored. To probe further the function of membrane anchoring in α2δ subunits, we have now examined the properties of α2δ-1 constructs truncated at their putative glycosylphosphatidylinositol anchor site, located before the C-terminal hydrophobic domain (α2δ-1ΔC-term). We find that the majority of α2δ-1ΔC-term is soluble and secreted into the medium, but unexpectedly, some of the protein remains associated with detergent-resistant membranes, also termed lipid rafts, and is extrinsically bound to the plasma membrane. Furthermore, heterologous co-expression of α2δ-1ΔC-term with CaV2.1/β1b results in a substantial enhancement of the calcium channel currents, albeit less than that produced by wild-type α2δ-1. These results call into question the role of membrane anchoring of α2δ subunits for calcium current enhancement. PMID:22869375

  17. Modeling and Simulation of Two Wheelchair Accessories for Pushing Doors.

    PubMed

    Abdullah, Soran Jalal; Shaikh Mohammed, Javeed

    2017-03-27

    Independent mobility is vital to individuals of all ages, and wheelchairs have proven to be great personal mobility devices. The tasks of opening and navigating through a door are trivial for healthy people, while the same tasks could be difficult for some wheelchair users. A wide range of intelligent wheelchair controllers and systems, robotic arms, or manipulator attachments integrated with wheelchairs have been developed for various applications, including manipulating door knobs. Unfortunately, the intelligent wheelchairs and robotic attachments are not widely available as commercial products. Therefore, the current manuscript presents the modeling and simulation of a novel but simple technology in the form of a passive wheelchair accessory (straight, arm-like with a single wheel, and arc-shaped with multiple wheels) for pushing doors open from a wheelchair. From the simulations using different wheel shapes and sizes, it was found that the arc-shaped accessory could push open the doors faster and with almost half the required force as compared to the arm-like accessory. Also, smaller spherical wheels were found to be best in terms of reaction forces on the wheels. Prototypes based on the arc-shaped accessory design will be manufactured and evaluated for pushing doors open and dodging or gliding other obstacles.

  18. Control of human energy expenditure by cytochrome c oxidase subunit IV-2.

    PubMed

    Schiffer, Tomas A; Peleli, Maria; Sundqvist, Michaela L; Ekblom, Björn; Lundberg, Jon O; Weitzberg, Eddie; Larsen, Filip J

    2016-09-01

    Resting metabolic rate (RMR) in humans shows pronounced individual variations, but the underlying molecular mechanism remains elusive. Cytochrome c oxidase (COX) plays a key role in control of metabolic rate, and recent studies of the subunit 4 isoform 2 (COX IV-2) indicate involvement in the cellular response to hypoxia and oxidative stress. We evaluated whether the COX subunit IV isoform composition may explain the pronounced individual variations in resting metabolic rate (RMR). RMR was determined in healthy humans by indirect calorimetry and correlated to levels of COX IV-2 and COX IV-1 in vastus lateralis. Overexpression and knock down of the COX IV isoforms were performed in primary myotubes followed by evaluation of the cell respiration and production of reactive oxygen species. Here we show that COX IV-2 protein is constitutively expressed in human skeletal muscle and strongly correlated to RMR. Primary human myotubes overexpressing COX IV-2 displayed markedly (>60%) lower respiration, reduced (>50%) cellular H2O2 production, higher resistance toward both oxidative stress, and severe hypoxia compared with control cells. These results suggest an important role of isoform COX IV-2 in the control of energy expenditure, hypoxic tolerance, and mitochondrial ROS homeostasis in humans. Copyright © 2016 the American Physiological Society.

  19. Adolescent accessory navicular.

    PubMed

    Leonard, Zachary C; Fortin, Paul T

    2010-06-01

    Accessory tarsal navicular is a common anomaly in the human foot. It should be in the differential of medial foot pain. A proper history and physical, along with imaging modalities, can lead to the diagnosis. Often, classification of the ossicle and amount of morbidity guide treatment. Nonsurgical measures can provide relief. A variety of surgical procedures have been used with good results. Our preferred method is excision for small ossicles and segmental fusion after removal of the synchondrosis for large ossicles. In addition, pes planovalgus deformities need to be addressed concomitantly. Copyright 2010 Elsevier Inc. All rights reserved.

  20. A Transmembrane Amino Acid in the GABAA Receptor β2 Subunit Critical for the Actions of Alcohols and Anesthetics

    PubMed Central

    McCracken, Mandy L.; Borghese, Cecilia M.; Trudell, James R.

    2010-01-01

    Alcohols and inhaled anesthetics enhance the function of GABAA receptors containing α, β, and γ subunits. Molecular analysis has focused on the role of the α subunits; however, there is evidence that the β subunits may also be important. The goal of our study was to determine whether Asn265, which is homologous to the site implicated in the α subunit (Ser270), contributes to an alcohol and volatile anesthetic binding site in the GABAA receptor β2 subunit. We substituted cysteine for Asn265 and exposed the mutant to the sulfhydryl-specific reagent octyl methanethiosulfonate (OMTS). We used two-electrode voltage-clamp electrophysiology in Xenopus laevis oocytes and found that, after OMTS application, GABA-induced currents were irreversibly potentiated in mutant α1β2(N265C)γ2S receptors [but not α1β2(I264C)γ2S], presumably because of the covalent linking of octanethiol to the thiol group in the substituted cysteine. It is noteworthy that this effect was blocked when OMTS was applied in the presence of octanol. We found that potentiation by butanol, octanol, or isoflurane in the N265C mutant was nearly abolished after the application of OMTS, suggesting that an alcohol and volatile anesthetic binding site at position 265 of the β2 subunit was irreversibly occupied by octanethiol and consequently prevented butanol or isoflurane from binding and producing their effects. OMTS did not affect modulation or direct activation by pentobarbital, but there was a partial reduction of allosteric modulation by flunitrazepam and alphaxalone in mutant α1β2(N265C)γ2S receptors after OMTS was applied. Our findings provide evidence that Asn265 may contribute to an alcohol and anesthetic binding site. PMID:20826568

  1. Impaired Discrimination Learning in Mice Lacking the NMDA Receptor NR2A Subunit

    ERIC Educational Resources Information Center

    Brigman, Jonathan L.; Feyder, Michael; Saksida, Lisa M.; Bussey, Timothy J.; Mishina, Masayoshi; Holmes, Andrew

    2008-01-01

    N-Methyl-D-aspartate receptors (NMDARs) mediate certain forms of synaptic plasticity and learning. We used a touchscreen system to assess NR2A subunit knockout mice (KO) for (1) pairwise visual discrimination and reversal learning and (2) acquisition and extinction of an instrumental response requiring no pairwise discrimination. NR2A KO mice…

  2. Variations in the surface anatomy of the spinal accessory nerve in the posterior triangle.

    PubMed

    Symes, A; Ellis, H

    2005-12-01

    Iatrogenic injury to the spinal accessory nerve has been widely documented and can have medico-legal implications. The resulting syndrome of pain, paralysis and winging of the scapula are often the source of considerable morbidity. This paper researches the degree of accuracy achievable in mapping the surface anatomy of the spinal accessory nerve in the region of the posterior triangle with a view to creating a cartographical aid to surgical procedures. The necks of 25 adult cadavers were dissected bilaterally to expose the spinal accessory nerve. Variations in the course and distribution of the spinal accessory nerve in the posterior triangle were recorded along with its relationship to the borders of sternocleidomastoid and trapezius. Considerable variation was seen in the surface and regional anatomy of the nerve and in the contribution of the cervical plexus to the spinal accessory nerve in the posterior triangle. Measurements of the running course and exit point of the nerve into and from the posterior triangle differed significantly from those previously recorded. Delineation of an accurate surface anatomy was not possible. Creating a map to define the surface anatomy of the spinal accessory nerve in the posterior triangle is an unrealistic goal given its wide variations in man. Avoidance of damage to the spinal accessory nerve cannot be achieved by slavishly adhering to surface markings given in textbooks, but only by cautious dissection during operations on the posterior triangle.

  3. 28 CFR 51.6 - Political subunits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Political subunits. 51.6 Section 51.6 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) PROCEDURES FOR THE ADMINISTRATION OF SECTION 5 OF THE VOTING RIGHTS ACT OF 1965, AS AMENDED General Provisions § 51.6 Political subunits. All political...

  4. 21 CFR 890.3910 - Wheelchair accessory.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Wheelchair accessory. 890.3910 Section 890.3910 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3910 Wheelchair...

  5. 21 CFR 890.3910 - Wheelchair accessory.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Wheelchair accessory. 890.3910 Section 890.3910 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3910 Wheelchair...

  6. 21 CFR 890.3910 - Wheelchair accessory.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Wheelchair accessory. 890.3910 Section 890.3910 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3910 Wheelchair...

  7. 21 CFR 890.3910 - Wheelchair accessory.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Wheelchair accessory. 890.3910 Section 890.3910 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3910 Wheelchair...

  8. 21 CFR 890.3910 - Wheelchair accessory.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Wheelchair accessory. 890.3910 Section 890.3910 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3910 Wheelchair...

  9. The A12.2 Subunit Is an Intrinsic Destabilizer of the RNA Polymerase I Elongation Complex.

    PubMed

    Appling, Francis D; Scull, Catherine E; Lucius, Aaron L; Schneider, David A

    2018-06-05

    Despite sharing a highly conserved core architecture with their prokaryotic counterparts, eukaryotic multisubunit RNA polymerases (Pols) have undergone structural divergence and biological specialization. Interesting examples of structural divergence are the A12.2 and C11 subunits of Pols I and III, respectively. Whereas all known cellular Pols possess cognate protein factors that stimulate cleavage of the nascent RNA, Pols I and III have incorporated their cleavage factors as bona fide subunits. Although it is not yet clear why these polymerases have incorporated their cleavage factors as subunits, a picture is emerging that identifies roles for these subunits beyond providing nucleolytic activity. Specifically, it appears that both A12.2 and C11 are required for efficient termination of transcription by Pols I and III. Given that termination involves destabilization of the elongation complex (EC), we tested whether A12.2 influences stability of the Pol I EC. Using, to our knowledge, a novel assay to measure EC dissociation kinetics, we have determined that A12.2 is an intrinsic destabilizer of the Pol I EC. In addition, the salt concentration dependence of Pol I EC dissociation kinetics suggests that A12.2 alters electrostatic interactions within the EC. Importantly, these data present a mechanistic basis for the requirement of A12.2 in Pol I termination. Combined with recent work demonstrating the direct involvement of A12.2 in Pol I nucleotide incorporation, this study further supports the concept that A12.2 cannot be viewed solely as a cleavage factor. Copyright © 2018 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  10. The tetramerization domain potentiates Kv4 channel function by suppressing closed-state inactivation.

    PubMed

    Tang, Yi-Quan; Zhou, Jing-Heng; Yang, Fan; Zheng, Jie; Wang, KeWei

    2014-09-02

    A-type Kv4 potassium channels undergo a conformational change toward a nonconductive state at negative membrane potentials, a dynamic process known as pre-open closed states or closed-state inactivation (CSI). CSI causes inhibition of channel activity without the prerequisite of channel opening, thus providing a dynamic regulation of neuronal excitability, dendritic signal integration, and synaptic plasticity at resting. However, the structural determinants underlying Kv4 CSI remain largely unknown. We recently showed that the auxiliary KChIP4a subunit contains an N-terminal Kv4 inhibitory domain (KID) that directly interacts with Kv4.3 channels to enhance CSI. In this study, we utilized the KChIP4a KID to probe key structural elements underlying Kv4 CSI. Using fluorescence resonance energy transfer two-hybrid mapping and bimolecular fluorescence complementation-based screening combined with electrophysiology, we identified the intracellular tetramerization (T1) domain that functions to suppress CSI and serves as a receptor for the binding of KID. Disrupting the Kv4.3 T1-T1 interaction interface by mutating C110A within the C3H1 motif of T1 domain facilitated CSI and ablated the KID-mediated enhancement of CSI. Furthermore, replacing the Kv4.3 T1 domain with the T1 domain from Kv1.4 (without the C3H1 motif) or Kv2.1 (with the C3H1 motif) resulted in channels functioning with enhanced or suppressed CSI, respectively. Taken together, our findings reveal a novel (to our knowledge) role of the T1 domain in suppressing Kv4 CSI, and that KChIP4a KID directly interacts with the T1 domain to facilitate Kv4.3 CSI, thus leading to inhibition of channel function. Copyright © 2014 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  11. P2X2 knockout mice and P2X2/P2X3 double knockout mice reveal a role for the P2X2 receptor subunit in mediating multiple sensory effects of ATP

    PubMed Central

    Cockayne, Debra A; Dunn, Philip M; Zhong, Yu; Rong, Weifang; Hamilton, Sara G; Knight, Gillian E; Ruan, Huai-Zhen; Ma, Bei; Yip, Ping; Nunn, Philip; McMahon, Stephen B; Burnstock, Geoffrey; Ford, Anthony PDW

    2005-01-01

    Extracellular ATP plays a role in nociceptive signalling and sensory regulation of visceral function through ionotropic receptors variably composed of P2X2 and P2X3 subunits. P2X2 and P2X3 subunits can form homomultimeric P2X2, homomultimeric P2X3, or heteromultimeric P2X2/3 receptors. However, the relative contribution of these receptor subtypes to afferent functions of ATP in vivo is poorly understood. Here we describe null mutant mice lacking the P2X2 receptor subunit (P2X2−/−) and double mutant mice lacking both P2X2 and P2X3 subunits (P2X2/P2X3Dbl−/−), and compare these with previously characterized P2X3−/− mice. In patch-clamp studies, nodose, coeliac and superior cervical ganglia (SCG) neurones from wild-type mice responded to ATP with sustained inward currents, while dorsal root ganglia (DRG) neurones gave predominantly transient currents. Sensory neurones from P2X2−/− mice responded to ATP with only transient inward currents, while sympathetic neurones had barely detectable responses. Neurones from P2X2/P2X3Dbl−/− mice had minimal to no response to ATP. These data indicate that P2X receptors on sensory and sympathetic ganglion neurones involve almost exclusively P2X2 and P2X3 subunits. P2X2−/− and P2X2/P2X3Dbl−/− mice had reduced pain-related behaviours in response to intraplantar injection of formalin. Significantly, P2X3−/−, P2X2−/−, and P2X2/P2X3Dbl−/− mice had reduced urinary bladder reflexes and decreased pelvic afferent nerve activity in response to bladder distension. No deficits in a wide variety of CNS behavioural tests were observed in P2X2−/− mice. Taken together, these data extend our findings for P2X3−/− mice, and reveal an important contribution of heteromeric P2X2/3 receptors to nociceptive responses and mechanosensory transduction within the urinary bladder. PMID:15961431

  12. Negative Factor from SIV Binds to the Catalytic Subunit of the V-ATPase to Internalize CD4 and to Increase Viral Infectivity

    PubMed Central

    Mandic, Robert; Fackler, Oliver T.; Geyer, Matthias; Linnemann, Thomas; Zheng, Yong-Hui; Peterlin, B. Matija

    2001-01-01

    The accessory protein negative factor (Nef) from human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) is required for optimal viral infectivity and the progression to acquired immunodeficiency syndrome (AIDS). Nef interacts with the endocytic machinery, resulting in the down-regulation of cluster of differentiation antigen 4 (CD4) and major histocompatibility complex class I (MHCI) molecules on the surface of infected cells. Mutations in the C-terminal flexible loop of Nef result in a lower rate of internalization by this viral protein. However, no loop-dependent binding of Nef to adaptor protein-2 (AP-2), which is the adaptor protein complex that is required for the internalization of proteins from the plasma membrane, could be demonstrated. In this study we investigated the relevance of different motifs in Nef from SIVmac239 for its internalization, CD4 down-regulation, binding to components of the trafficking machinery, and viral infectivity. Our data suggest that the binding of Nef to the catalytic subunit H of the vacuolar membrane ATPase (V-ATPase) facilitates its internalization. This binding depends on the integrity of the whole flexible loop. Subsequent studies on Nef mutant viruses revealed that the flexible loop is essential for optimal viral infectivity. Therefore, our data demonstrate how Nef contacts the endocytic machinery in the absence of its direct binding to AP-2 and suggest an important role for subunit H of the V-ATPase in viral infectivity. PMID:11179428

  13. CK2(beta)tes gene encodes a testis-specific isoform of the regulatory subunit of casein kinase 2 in Drosophila melanogaster.

    PubMed

    Kalmykova, Alla I; Shevelyov, Yuri Y; Polesskaya, Oksana O; Dobritsa, Anna A; Evstafieva, Alexandra G; Boldyreff, Brigitte; Issinger, Olaf-Georg; Gvozdev, Vladimir A

    2002-03-01

    An earlier described CK2(beta)tes gene of Drosophila melanogaster is shown to encode a male germline specific isoform of regulatory beta subunit of casein kinase 2. Western-analysis using anti-CK2(beta)tes Ig revealed CK2(beta)tes protein in Drosophila testes extract. Expression of a CK2(beta)tes-beta-galactosidase fusion protein driven by the CK2(beta)tes promoter was found in transgenic flies at postmitotic stages of spermatogenesis. Examination of biochemical characteristics of a recombinant CK2(beta)tes protein expressed in Escherichia coli revealed properties similar to those of CK2beta: (a) CK2(beta)tes protein stimulates CK2alpha catalytic activity toward synthetic peptide; (b) it inhibits phosphorylation of calmodulin and mediates stimulation of CK2alpha by polylysine; (c) it is able to form (CK2(beta)tes)2 dimers, as well as (CK2alpha)2(CK2(beta)tes)2 tetramers. Using the yeast two-hybrid system and coimmunoprecipitation analysis of protein extract from Drosophila testes, we demonstrated an association between CK2(beta)tes and CK2alpha. Northern-analysis has shown that another regulatory (beta') subunit found recently in D. melanogaster genome is also testis-specific. Thus, we describe the first example of two tissue-specific regulatory subunits of CK2 which might serve to provide CK2 substrate recognition during spermatogenesis.

  14. 29 CFR 1919.28 - Unit proof tests-cranes and gear accessory thereto.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Unit proof tests-cranes and gear accessory thereto. 1919.28... ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) GEAR CERTIFICATION Certification of Vessels: Tests and Proof Loads; Heat Treatment; Competent Persons § 1919.28 Unit proof tests—cranes and gear accessory thereto...

  15. Two highly-related regulatory subunits of PP2A exert opposite effects on TGF-β/Activin/Nodal signalling

    PubMed Central

    Batut, Julie; Schmierer, Bernhard; Cao, Jing; Raftery, Laurel A.; Hill, Caroline S.; Howell, Michael

    2016-01-01

    Summary We identify Bα (PPP2R2A) and Bδ (PPP2R2D), two highly-related members of the B family of regulatory subunits of the protein phosphatase PP2A, as important modulators of TGF-β/Activin/Nodal signalling, which affect the pathway in opposite ways. Knockdown of Bα in Xenopus embryos or mammalian tissue culture cells suppresses TGF-β/Activin/Nodal-dependent responses, whereas knockdown of Bδ enhances these responses. Moreover, in Drosophila, overexpression of Smad2 rescues a severe wing phenotype caused by overexpression of the single Drosophila PP2A B subunit, Twins. We show that in vertebrates Bα enhances TGF-β/Activin/Nodal signalling by stabilising the basal levels of type I receptor, whereas Bδ negatively modulates these pathways by restricting receptor activity. Thus, these highly-related members of the same subfamily of PP2A regulatory subunits differentially regulate TGF-β/Activin/Nodal signalling to elicit opposing biological outcomes. PMID:18697906

  16. Α2 GABAA receptor sub-units in the ventral hippocampus and α5 GABAA receptor sub-units in the dorsal hippocampus mediate anxiety and fear memory.

    PubMed

    McEown, K; Treit, D

    2013-11-12

    Temporary neuronal inactivation of the ventral hippocampus with the GABAA agonist muscimol suppresses unconditioned fear behavior (anxiety) but inactivation of the dorsal hippocampus does not. On the other hand, inactivating the dorsal hippocampus disrupts fear memory, while inactivating the ventral hippocampus does not. Here we investigate the roles of hippocampal GABAA receptor sub-units in mediating these anxiolytic and amnesic effects of GABAA receptor agonists. We microinfused TPA023 (α2 agonist) or TB-21007 (inverse α5 agonist) into the dorsal or ventral hippocampus prior to testing rats in two animal models of anxiety: the elevated plus-maze and shock-probe burying test. Twenty-four hours later rats were re-tested in the shock-probe chamber with a non-electrified probe to assess their memory of the initial shock-probe experience (i.e., fear memory). We found that TPA023 was anxiolytic in the plus-maze and shock-probe burying tests when microinfused into the ventral hippocampus. However, TPA023 did not affect anxiety-related behavior when infused into the dorsal hippocampus. Conversely, we found that the α5 sub-unit inverse agonist TB-21007 impaired rats' memory of the initial shock-probe experience when infused into the dorsal hippocampus, but not when infused into the ventral hippocampus. This double dissociation suggests that α2 GABAA receptor sub-units in the ventral hippocampus mediate unconditioned fear or anxiety, while α5 GABAA receptor sub-units in the dorsal hippocampus mediate conditioned fear memory. Copyright © 2013 IBRO. Published by Elsevier Ltd. All rights reserved.

  17. Comparative anatomy of the accessory ciliary ganglion in mammals.

    PubMed

    Kuchiiwa, S; Kuchiiwa, T; Suzuki, T

    1989-01-01

    The orbits of 13 mammalian species (pig, sika deer, domestic sheep, horse, cat, fox, racoon dog, marten, rat, rabbit, crab-eating macaque, japanese macaque and man) were stained with silver nitrate and dissected under a dissecting microscope with special attention to the presence and location of the accessory ciliary ganglion. Some preparations were stained with thionin and examined as whole-mounts in a transmission microscope. The accessory ciliary ganglion was present in all 13 species, although the number and degree of development varied greatly from species to species. The accessory ciliary ganglion could be readily differentiated from the main ciliary ganglion in the following respects: it was located on the short ciliary nerve, and it had no root derived directly from the inferior trunk of the oculomotor nerve and it never attaches to this nerve. In many species, ganglion cells were also scattered in the short ciliary nerves in the stained whole preparations. In a few species, there were one or more small ganglia on the nerve to the inferior oblique muscle.

  18. An evolutionary switch in ND2 enables Src kinase regulation of NMDA receptors

    NASA Astrophysics Data System (ADS)

    Scanlon, David P.; Bah, Alaji; Krzeminski, Mickaël; Zhang, Wenbo; Leduc-Pessah, Heather L.; Dong, Yi Na; Forman-Kay, Julie D.; Salter, Michael W.

    2017-05-01

    The non-receptor tyrosine kinase Src is a key signalling hub for upregulating the function of N-methyl D-aspartate receptors (NMDARs). Src is anchored within the NMDAR complex via NADH dehydrogenase subunit 2 (ND2), a mitochondrially encoded adaptor protein. The interacting regions between Src and ND2 have been broadly identified, but the interaction between ND2 and the NMDAR has remained elusive. Here we generate a homology model of ND2 and dock it onto the NMDAR via the transmembrane domain of GluN1. This interaction is enabled by the evolutionary loss of three helices in bilaterian ND2 proteins compared to their ancestral homologues. We experimentally validate our model and demonstrate that blocking this interaction with an ND2 fragment identified in our experimental studies prevents Src-mediated upregulation of NMDAR currents in neurons. Our findings establish the mode of interaction between an NMDAR accessory protein with one of the core subunits of the receptor.

  19. Diverse Broad-Host-Range Plasmids from Freshwater Carry Few Accessory Genes

    PubMed Central

    Sen, Diya; Yano, Hirokazu; Bauer, Matthew L.; Rogers, Linda M.; Van der Auwera, Geraldine A.

    2013-01-01

    Broad-host-range self-transferable plasmids are known to facilitate bacterial adaptation by spreading genes between phylogenetically distinct hosts. These plasmids typically have a conserved backbone region and a variable accessory region that encodes host-beneficial traits. We do not know, however, how well plasmids that do not encode accessory functions can survive in nature. The goal of this study was to characterize the backbone and accessory gene content of plasmids that were captured from freshwater sources without selecting for a particular phenotype or cultivating their host. To do this, triparental matings were used such that the only required phenotype was the plasmid's ability to mobilize a nonconjugative plasmid. Based on complete genome sequences of 10 plasmids, only 5 carried identifiable accessory gene regions, and none carried antibiotic resistance genes. The plasmids belong to four known incompatibility groups (IncN, IncP-1, IncU, and IncW) and two potentially new groups. Eight of the plasmids were shown to have a broad host range, being able to transfer into alpha-, beta-, and gammaproteobacteria. Because of the absence of antibiotic resistance genes, we resampled one of the sites and compared the proportion of captured plasmids that conferred antibiotic resistance to their hosts with the proportion of such plasmids captured from the effluent of a local wastewater treatment plant. Few of the captured plasmids from either site encoded antibiotic resistance. A high diversity of plasmids that encode no or unknown accessory functions is thus readily found in freshwater habitats. The question remains how the plasmids persist in these microbial communities. PMID:24096417

  20. Archaeal translation initiation revisited: the initiation factor 2 and eukaryotic initiation factor 2B alpha-beta-delta subunit families

    NASA Technical Reports Server (NTRS)

    Kyrpides, N. C.; Woese, C. R.

    1998-01-01

    As the amount of available sequence data increases, it becomes apparent that our understanding of translation initiation is far from comprehensive and that prior conclusions concerning the origin of the process are wrong. Contrary to earlier conclusions, key elements of translation initiation originated at the Universal Ancestor stage, for homologous counterparts exist in all three primary taxa. Herein, we explore the evolutionary relationships among the components of bacterial initiation factor 2 (IF-2) and eukaryotic IF-2 (eIF-2)/eIF-2B, i.e., the initiation factors involved in introducing the initiator tRNA into the translation mechanism and performing the first step in the peptide chain elongation cycle. All Archaea appear to posses a fully functional eIF-2 molecule, but they lack the associated GTP recycling function, eIF-2B (a five-subunit molecule). Yet, the Archaea do posses members of the gene family defined by the (related) eIF-2B subunits alpha, beta, and delta, although these are not specifically related to any of the three eukaryotic subunits. Additional members of this family also occur in some (but by no means all) Bacteria and even in some eukaryotes. The functional significance of the other members of this family is unclear and requires experimental resolution. Similarly, the occurrence of bacterial IF-2-like molecules in all Archaea and in some eukaryotes further complicates the picture of translation initiation. Overall, these data lend further support to the suggestion that the rudiments of translation initiation were present at the Universal Ancestor stage.

  1. PKC/CREB pathway mediates the expressions of GABAA receptor subunits in cultured hippocampal neurons after low-Mg2+ solution treatment.

    PubMed

    Wu, Guofeng; Yu, Jinpeng; Wang, Likun; Ren, Siying; Zhang, Yixia

    2018-02-01

    To investigate the potential effects of the PKC/CREB pathway on the expressions of GABA A receptor subunits α1, γ2, and δ in cultured hippocampal neurons using a model of epilepsy that employed conditions of low magnesium (Mg 2+ ). A total of 108 embryonic rats at the age of 18 embryonic days (E18)prepared from adult female SD rats were used as experimental subjects. Primary rat hippocampal cultures were prepared from the embryonic 18 days rats. The cultured hippocampal neurons were then treated with artificial cerebrospinal fluid containing low Mg 2+ solutions to generate a low Mg 2+ model of epilepsy. The low Mg 2+ stimulation lasted for 3 h and then returned to in maintenance medium for 20 h. The changes of the GABA A receptor subunit α1, γ2, δ were observed by blocking or activating the function of the CREB. The quantification of the GABA A receptor subunit α1, γ2, δ and the CREB were determined by a qRT-PCR and a Western blot method. After the neurons were exposed to a low-Mg 2+ solution for 3 h, GABA A receptor mRNA expression markedly increased compared to the control, and then gradually decreased. In contrast, CREB mRNA levels exhibited a dramatic down-regulation 3 h after terminating low-Mg 2+ treatment, and then peaked at 9 h. Western blot analyses verified that staurosporine suppressed CREB phosphorylation (p-CREB). The mRNA expression of GABA A receptor subunit α1 increased only in the presence of staurosporine, whereas the expressions of subunits γ2 and δ significantly increased in the presence of either KG-501 or staurosporine. Furthermore, phorbol 12-myristate 13-acetate (PMA) decreased the expressions of GABA A subunits α1, γ2, and δ when administered alone. However, the administration of either KG-501 or staurosporine reversed the inhibitory effects of PMA. The PKC/CREB pathway may negatively regulate the expressions of GABA A receptor subunits α1, γ2, and δ in cultured hippocampal neurons in low Mg 2+ model of

  2. 47 CFR 15.27 - Special accessories.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false Special accessories. 15.27 Section 15.27 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES General § 15.27 Special... manual is provided only in a form other than paper, such as on a computer disk or over the Internet, the...

  3. 47 CFR 15.27 - Special accessories.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false Special accessories. 15.27 Section 15.27 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES General § 15.27 Special... manual is provided only in a form other than paper, such as on a computer disk or over the Internet, the...

  4. 47 CFR 15.27 - Special accessories.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false Special accessories. 15.27 Section 15.27 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES General § 15.27 Special... manual is provided only in a form other than paper, such as on a computer disk or over the Internet, the...

  5. 47 CFR 15.27 - Special accessories.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false Special accessories. 15.27 Section 15.27 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES General § 15.27 Special... manual is provided only in a form other than paper, such as on a computer disk or over the Internet, the...

  6. 29 CFR 1919.28 - Unit proof tests-cranes and gear accessory thereto.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 7 2011-07-01 2011-07-01 false Unit proof tests-cranes and gear accessory thereto. 1919.28... Loads; Heat Treatment; Competent Persons § 1919.28 Unit proof tests—cranes and gear accessory thereto. (a) Except as noted in paragraph (e) of this section, cranes and other hoisting machines, together...

  7. Adenoid Cystic Carcinoma of Accessory Parotid Gland: A Case Report.

    PubMed

    Das, Somdipto; Nayak, Umanath K; Buggavetti, Rahul; Sekhar, Shobana

    2016-05-01

    The accessory parotid gland is salivary gland tissue separated from the main gland at a variable distance. This gland is histologically similar to the main gland, but has a higher incidence of malignant neoplasms than the main gland. Regarding the various malignant neoplasms, studies have shown higher incidences of mucoepidermoid carcinoma, with less than 2% being adenoid cystic carcinoma. We present a case of swelling in the midcheek region that, after clinical examination, was diagnosed as a case of neoplasm of the accessory parotid gland. On the basis of auxiliary investigations including intraoperative frozen section, it was concluded that it was adenoid cystic carcinoma, grade I, and after wide surgical resection, the tumor was removed without undergoing superficial parotidectomy. The patient received postoperative radiotherapy (RT) and was followed for 14 months without any recurrence or substantial facial asymmetry. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  8. Subunit association of gamma-glutamyltranspeptidase of Escherichia coli K-12.

    PubMed

    Hashimoto, W; Suzuki, H; Nohara, S; Tachi, H; Yamamoto, K; Kumagai, H

    1995-12-01

    gamma-Glutamyltranspeptidase [EC 2.3.2.2] of Escherichia coli K-12 consists of one large subunit and one small subunit, which can be separated from each other by high-performance liquid chromatography. Using ion spray mass spectrometry, the masses of the large and the small subunit were determined to be 39,207 and 20,015, respectively. The large subunit exhibited no gamma-glutamyltranspeptidase activity and the small subunit had little enzymatic activity, but a mixture of the two subunits showed partial recovery of the enzymatic activity. The results of native-polyacrylamide gel electrophoresis suggested that they could partially recombine, and that the recombined dimer exhibited enzymatic activity. The gene of gamma-glutamyltranspeptidase encoded a signal peptide, and the large and small subunits in a single open reading frame in that order. Two kinds of plasmid were constructed encoding the signal peptide and either the large or the small subunit. A gamma-glutamyltranspeptidase-less mutant of E. coli K-12 was transformed with each plasmid or with both of them. The strain harboring the plasmid encoding each subunit produced a small amount of the corresponding subunit protein in the periplasmic space but exhibited no enzymatic activity. The strain transformed with both plasmids together exhibited the enzymatic activity, but its specific activity was approximately 3% of that of a strain harboring a plasmid encoding the intact structural gene. These results indicate that a portion of the separated large and small subunits can be reconstituted in vitro and exhibit the enzymatic activity, and that the expressed large and small subunits independently are able to associate in vivo and be folded into an active structure, though the specific activity of the associated subunits was much lower than that of native enzyme. This suggests that the synthesis of gamma-glutamyltranspeptidase in a single precursor polypeptide and subsequent processing are more effective to construct

  9. Electrophysiological mapping of the accessory olfactory bulb of the rabbit (Oryctolagus cuniculus).

    PubMed

    van Groen, T; Ruardy, L; da Silva, F H

    1986-07-01

    Field potentials elicited by electrical stimulation of the vomeronasal nerve were measured in the accessory olfactory bulb of the rabbit. Maps were made of the distribution of surface field potentials and of the corresponding depth profiles. The surface maps followed closely the contours of the accessory olfactory bulb: at the frontal border the field potential tended to zero and at the center of the structure the field potential attained a maximum. Depth profiles of the field potentials through the accessory olfactory bulb presented a surface-negative wave and, in depth, a positive wave. The polarity reversal occurred at the deep part of the granule cell layer. The zero equipotential line followed closely the curvature of the granule cell layer. Current source density analysis of the depth profiles revealed a main sink at the external plexiform and granule cell layers. This indicates that the main activity in the accessory olfactory bulb is generated by the synapses between the mitral cells and the granule cells as is found in the main olfactory bulb.

  10. Accessory atrioventricular pathways refractory to catheter ablation: role of percutaneous epicardial approach.

    PubMed

    Scanavacca, Maurício Ibrahim; Sternick, Eduardo Back; Pisani, Cristiano; Lara, Sissy; Hardy, Carina; d'Ávila, André; Correa, Frederico Soares; Darrieux, Francisco; Hachul, Denise; Marcial, Miguel Barbero; Sosa, Eduardo A

    2015-02-01

    Epicardial mapping and ablation of accessory pathways through a subxiphoid approach can be an alternative when endocardial or epicardial transvenous mapping has failed. We reviewed acute and long-term follow-up of 21 patients (14 males) referred for percutaneous epicardial accessory pathway ablation. There was a median of 2 previous failed procedures. All patients were highly symptomatic, 8 had atrial fibrillation (3 with cardiac arrest) and 13 had frequent symptomatic episodes of atrioventricular reentrant tachycardia. Six patients (28.5%) had a successful epicardial ablation. Five patients (23.8%) underwent a successful repeated endocardial mapping, and ablation after epicardial mapping yielded no early activation site. Epicardial mapping was helpful in guiding endocardial ablation in 2 patients (9.5%), showing that the earliest activation was simultaneous at the epicardium and endocardium. Four patients (19%) underwent successful open-chest surgery after failing epicardial/endocardial ablation. Two patients (9.5%) remained controlled under antiarrhythmic drugs after unsuccessful endocardial/epicardial ablation. Two patients had a coronary sinus diverticulum and one a right atrium to right ventricle diverticulum. Three patients acquired postablation coronary sinus stenosis. There was no major complication related to pericardial access. Percutaneous epicardial approach is an alternative when conventional endocardial or transvenous epicardial ablation fails in the elimination of the accessory pathway. A new attempt by endocardial approach was successful in a significant number of patients. Open-chest surgery may be required in symptomatic cases refractory to endocardial-epicardial approach. © 2014 American Heart Association, Inc.

  11. 21 CFR 884.4100 - Endoscopic electrocautery and accessories.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... coagulate fallopian tube tissue with a probe heated by low-voltage energy. This generic type of device may include the following accessories: electrical generators, probes, and electrical cables. (b...

  12. 21 CFR 884.4100 - Endoscopic electrocautery and accessories.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... coagulate fallopian tube tissue with a probe heated by low-voltage energy. This generic type of device may include the following accessories: electrical generators, probes, and electrical cables. (b...

  13. 21 CFR 884.4100 - Endoscopic electrocautery and accessories.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... coagulate fallopian tube tissue with a probe heated by low-voltage energy. This generic type of device may include the following accessories: electrical generators, probes, and electrical cables. (b...

  14. 21 CFR 884.4100 - Endoscopic electrocautery and accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... coagulate fallopian tube tissue with a probe heated by low-voltage energy. This generic type of device may include the following accessories: electrical generators, probes, and electrical cables. (b...

  15. 21 CFR 884.1720 - Gynecologic laparoscope and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... genital organs. This generic type of device may include: Trocar and cannula, instruments used through an... accessory instruments include: the lens cleaning brush, biopsy brush, clip applier (without clips...

  16. 21 CFR 884.1720 - Gynecologic laparoscope and accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... genital organs. This generic type of device may include: Trocar and cannula, instruments used through an... accessory instruments include: the lens cleaning brush, biopsy brush, clip applier (without clips...

  17. Relative positioning of classical benzodiazepines to the γ2-subunit of GABAA receptors.

    PubMed

    Middendorp, Simon J; Hurni, Evelyn; Schönberger, Matthias; Stein, Marco; Pangerl, Michael; Trauner, Dirk; Sigel, Erwin

    2014-08-15

    GABAA receptors are the major inhibitory neurotransmitter receptors in the brain. Benzodiazepine exert their action via a high affinity-binding site at the α/γ subunit interface on some of these receptors. Diazepam has sedative, hypnotic, anxiolytic, muscle relaxant, and anticonvulsant effects. It acts by potentiating the current evoked by the agonist GABA. Understanding specific interaction of benzodiazepines in the binding pocket of different GABAA receptor isoforms might help to separate these divergent effects. As a first step, we characterized the interaction between diazepam and the major GABAA receptor isoform α1β2γ2. We mutated several amino acid residues on the γ2-subunit assumed to be located near or in the benzodiazepine binding pocket individually to cysteine and studied the interaction with three ligands that are modified with a cysteine-reactive isothiocyanate group (-NCS). When the reactive NCS group is in apposition to the cysteine residue this leads to a covalent reaction. In this way, three amino acid residues, γ2Tyr58, γ2Asn60, and γ2Val190 were located relative to classical benzodiazepines in their binding pocket on GABAA receptors.

  18. Large conductance Ca(2+)-activated K(+) channel (BKCa) activating properties of a series of novel N-arylbenzamides: Channel subunit dependent effects.

    PubMed

    Kirby, R W; Martelli, A; Calderone, V; McKay, N G; Lawson, K

    2013-07-15

    Large conductance calcium activated potassium channels (BKCa) are fundamental in the control of cellular excitability. Thus, compounds that activate BKCa channels could provide potential therapies in the treatment of pathologies of the cardiovascular and central nervous system. A series of novel N-arylbenzamide compounds, and the reference compound NS1619, were evaluated for BKCa channel opener properties in Human Embryonic Kidney (HEK293) cells expressing the human BKCa channel α-subunit alone or α+β1-subunit complex. Channel activity was determined using a non-radioactive Rb(+) efflux assay to construct concentration effect curves for each compound. All N-arylbenzamide compounds and NS1619 evoked significant (p <0.05) concentration related increases in Rb(+) efflux both in cells expressing α-subunit alone or α+β1-subunits. Co-expression of the β1-subunit modified the Rb(+) efflux responses, relative to that obtained in cells expressing the α-subunit alone, for most of the N-arylbenzamide compounds, in contrast to NS1619. The EC40 values of NS1619, BKMe1 and BKOEt1 were not significantly affected by the co-expression of the BKCa channel α+β1-subunits. In contrast, 5 other N-arylbenzamides (BKPr2, BKPr3, BKPr4, BKH1 and BKVV) showed a significant (p <0.05) 2- to 10-fold increase in EC40 values when tested on the BKCa α+β1-subunit expressing cells compared to BKCa α-subunit expressing cells. Further, the Emax values for BKPr4, BKVV and BKH1 were lower in the BKCa channel α+β1-subunit expressing cells. In conclusion, the N-arylbenzamides studied, like NS1619, were able to activate BKCa channels formed of the α-subunit only. The co-expression of the β1-subunit, however, modified the ability of certain compounds to active the channel leading to differentiated pharmacodynamic profiles. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. 21 CFR 888.3030 - Single/multiple component metallic bone fixation appliances and accessories.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Single/multiple component metallic bone fixation....3030 Single/multiple component metallic bone fixation appliances and accessories. (a) Identification. Single/multiple component metallic bone fixation appliances and accessories are devices intended to be...

  20. 21 CFR 888.3030 - Single/multiple component metallic bone fixation appliances and accessories.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Single/multiple component metallic bone fixation....3030 Single/multiple component metallic bone fixation appliances and accessories. (a) Identification. Single/multiple component metallic bone fixation appliances and accessories are devices intended to be...

  1. 21 CFR 888.3030 - Single/multiple component metallic bone fixation appliances and accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Single/multiple component metallic bone fixation....3030 Single/multiple component metallic bone fixation appliances and accessories. (a) Identification. Single/multiple component metallic bone fixation appliances and accessories are devices intended to be...

  2. 21 CFR 888.3030 - Single/multiple component metallic bone fixation appliances and accessories.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Single/multiple component metallic bone fixation....3030 Single/multiple component metallic bone fixation appliances and accessories. (a) Identification. Single/multiple component metallic bone fixation appliances and accessories are devices intended to be...

  3. 21 CFR 888.3030 - Single/multiple component metallic bone fixation appliances and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Single/multiple component metallic bone fixation....3030 Single/multiple component metallic bone fixation appliances and accessories. (a) Identification. Single/multiple component metallic bone fixation appliances and accessories are devices intended to be...

  4. Knockout of the BK β2 subunit abolishes inactivation of BK currents in mouse adrenal chromaffin cells and results in slow-wave burst activity

    PubMed Central

    Martinez-Espinosa, Pedro L.; Yang, Chengtao; Gonzalez-Perez, Vivian; Xia, Xiao-Ming

    2014-01-01

    Rat and mouse adrenal medullary chromaffin cells (CCs) express an inactivating BK current. This inactivation is thought to arise from the assembly of up to four β2 auxiliary subunits (encoded by the kcnmb2 gene) with a tetramer of pore-forming Slo1 α subunits. Although the physiological consequences of inactivation remain unclear, differences in depolarization-evoked firing among CCs have been proposed to arise from the ability of β2 subunits to shift the range of BK channel activation. To investigate the role of BK channels containing β2 subunits, we generated mice in which the gene encoding β2 was deleted (β2 knockout [KO]). Comparison of proteins from wild-type (WT) and β2 KO mice allowed unambiguous demonstration of the presence of β2 subunit in various tissues and its coassembly with the Slo1 α subunit. We compared current properties and cell firing properties of WT and β2 KO CCs in slices and found that β2 KO abolished inactivation, slowed action potential (AP) repolarization, and, during constant current injection, decreased AP firing. These results support the idea that the β2-mediated shift of the BK channel activation range affects repetitive firing and AP properties. Unexpectedly, CCs from β2 KO mice show an increased tendency toward spontaneous burst firing, suggesting that the particular properties of BK channels in the absence of β2 subunits may predispose to burst firing. PMID:25267913

  5. Triclosan-Evoked Neurotoxicity Involves NMDAR Subunits with the Specific Role of GluN2A in Caspase-3-Dependent Apoptosis.

    PubMed

    Szychowski, Konrad A; Wnuk, Agnieszka; Rzemieniec, Joanna; Kajta, Małgorzata; Leszczyńska, Teresa; Wójtowicz, Anna K

    2018-04-19

    Triclosan (TCS) is an antimicrobial agent that is used extensively in personal care and in sanitising products. A number of studies have shown the presence of TCS in different human tissues such as blood, adipose tissue, the liver, brain as well as in breast milk and urine. N-Methyl-D-aspartate receptors (NMDARs) are glutamate-gated ion channels that are widely expressed in the central nervous system and which play key roles in excitatory synaptic transmission. There is, however, no data on the involvement of NMDAR subunits in the apoptotic and neurotoxic effects of TCS. Our experiments are the first to show that TCS used at environmentally relevant concentrations evoked NMDA-dependent effects in neocortical neurons in primary cultures, as MK-801, an uncompetitive NMDA receptor antagonist, reduced the levels of TCS-induced ROS production as well as caspase-3 activity and LDH release. TCS caused a decrease in protein expression of all the studied NMDA receptor subunits (GluN1, GluN2A, GluN2B) that were measured at 3, 6 and 24 h post-treatment. However, at 48 h of the experiment, the level of the GluN1 subunit returned to the control level, and the levels of the other subunits showed a tendency to increase. In TCS-treated neocortical cells, protein profiles of NMDAR subunits measured up to 24 h were similar to mRNA expression of GluN1 and GluN2A, but not to GluN2B mRNA. In this study, cells transiently transfected with GluN1, GluN2A or GluN2B siRNA exhibited reduced levels of LDH release, which suggests the involvement of all of the studied NMDAR subunits in the neurotoxic action of TCS. According to our data, GluN1 and GluN2A were mainly responsible for neuronal cell death as evidenced by neutral red uptake, whereas GluN2A was involved in TCS-induced caspase-3-dependent apoptosis. We suggest that TCS-evoked apoptosis and neurotoxicity could be related to transient degradation of NMDAR subunits in mouse neurons. Furthermore, recycling of NMDAR subunits in response

  6. Differential agonist sensitivity of glycine receptor α2 subunit splice variants

    PubMed Central

    Miller, Paul S; Harvey, Robert J; Smart, Trevor G

    2004-01-01

    The glycine receptor (GlyR) α2A and α2B splice variants differ by a dual, adjacent amino acid substitution from α2AV58,T59 to α2BI58,A59 in the N-terminal extracellular domain. Comparing the effects of the GlyR agonists, glycine, β-alanine and taurine, on the GlyR α2 isoforms, revealed a significant increase in potency for all three agonists at the α2B variant. The sensitivities of the splice variants to the competitive antagonist, strychnine, and to the biphasic modulator Zn2+, were comparable. In contrast, the allosteric inhibitor picrotoxin was more potent on GlyR α2A compared to GlyR α2B receptors. Coexpression of α2A or α2B subunits with the GlyR β subunit revealed that the higher agonist potencies observed with the α2B homomer were retained for the α2Bβ heteromer. The identical sensitivity to strychnine combined with a reduction in the maximum current induced by the partial agonist taurine at the GlyR α2A homomer, suggested that the changed sensitivity to agonists is in accordance with a modulation of agonist efficacy rather than agonist affinity. An effect on agonist efficacy was also supported by using a structural model of the GlyR, localising the region of splice variation to the proposed docking region between GlyR loop 2 and the TM2-3 loop, an area associated with channel activation. The existence of a spasmodic mouse phenotype linked to a GlyR α1A52S mutation, the equivalent position to the source of the α2 splice variation, raises the possibility that the GlyR α2 splice variants may be responsible for distinct roles in neuronal function. PMID:15302677

  7. Removal of GABAA Receptor γ2 Subunits from Parvalbumin Neurons Causes Wide-Ranging Behavioral Alterations

    PubMed Central

    Leppä, Elli; Linden, Anni-Maija; Vekovischeva, Olga Y.; Swinny, Jerome D.; Rantanen, Ville; Toppila, Esko; Höger, Harald; Sieghart, Werner; Wulff, Peer; Wisden, William; Korpi, Esa R.

    2011-01-01

    We investigated the behavioral significance of fast synaptic inhibition by αβγ2-type GABAA receptors on parvalbumin (Pv) cells. The GABAA receptor γ2 subunit gene was selectively inactivated in Pv-positive neurons by Cre/loxP recombination. The resulting Pv-Δγ2 mice were relatively healthy in the first postnatal weeks; but then as Cre started to be expressed, the mice progressively developed wide-ranging phenotypic alterations including low body weight, motor deficits and tremor, decreased anxiety levels, decreased pain sensitivity and deficient prepulse inhibition of the acoustic startle reflex and impaired spatial learning. Nevertheless, the deletion was not lethal, and mice did not show increased mortality even after one year. Autoradiography with t-butylbicyclophosphoro[35S]thionate suggested an increased amount of GABAA receptors with only α and β subunits in central nervous system regions that contained high levels of parvalbumin neurons. Using BAC-transgenesis, we reduced some of the Pv-Δγ2 phenotype by selectively re-expressing the wild-type γ2 subunit back into some Pv cells (reticular thalamic neurons and cerebellar Pv-positive neurons). This produced less severe impairments of motor skills and spatial learning compared with Pv-Δγ2 mice, but all other deficits remained. Our results reveal the widespread significance of fast GABAergic inhibition onto Pv-positive neurons for diverse behavioral modalities, such as motor coordination, sensorimotor integration, emotional behavior and nociception. PMID:21912668

  8. Successful catheter ablation of a left anterior accessory pathway from the non-coronary cusp of the aortic valve.

    PubMed

    Laranjo, Sérgio; Oliveira, Mário; Trigo, Conceição

    2015-08-01

    Left anterior accessory pathways are considered to be rare findings. Catheter ablation of accessory pathways in this location remains a challenging target, and few reports about successful ablation of these accessory pathways are available. We describe our experience regarding a case of a manifest left anterior accessory pathway ablation using radiofrequency energy at the junction of the left coronary cusp with the non-coronary cusp.

  9. Mammotome-Assisted Liposuction: A Novel Technique for Accessory Breasts.

    PubMed

    Tang, Xin

    2017-06-01

    Due to its minimally invasive and highly precise nature, the mammotome, a vacuum-assisted breast biopsy device, has proven effective for the treatment of benign breast lesions. Taking advantage of both liposuction and the mammotome, we utilized the mammotome device for the excision of accessory breasts. Between July 2010 and June 2014, 16 patients with accessory breasts received mammotome-assisted liposuction. After adipose was removed using this procedure, the mammotome system was used to excise the fibro-glandular tissue in accessory breasts under ultrasound monitoring. All patients were satisfied with their appearance after surgery. A single 5-mm incision, which was well hidden in the axillary skin folds and allowed for restoration, provided an aesthetically pleasing contour to the axilla. Mammotome-assisted liposuction is a new approach that can be used to excise both adipose and fibro-glandular breast tissue simultaneously with a minimal incision, and provides a favorable contour to the axilla. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

  10. Accessory carpal bone luxation in two gray wolves (Canis lupus).

    PubMed

    Keller, Dominique L; Ellison, Michelle; Clyde, Victoria L; Wallace, Roberta S

    2012-09-01

    Two sibling male castrated gray wolves (Canis lupus) developed acute onset right forelimb lameness, one at 8 and the other at 11 yr of age. In both cases, the right carpus was swollen, carpal hyperextension was notable, and the wolves exhibited significant intermittent lameness of the affected limb. Radiographs revealed right accessory carpal bone luxation in both cases, with type III fracture of the accessory carpal bone in one wolf. Although carpal bone luxation in domestic dogs is frequently treated surgically, conservative medical management resolved the lameness in both wolves with no further complications.

  11. Computer modeling of siRNA knockdown effects indicates an essential role of the Ca2+ channel alpha2delta-1 subunit in cardiac excitation-contraction coupling.

    PubMed

    Tuluc, Petronel; Kern, Georg; Obermair, Gerald J; Flucher, Bernhard E

    2007-06-26

    L-type Ca(2+) currents determine the shape of cardiac action potentials (AP) and the magnitude of the myoplasmic Ca(2+) signal, which regulates the contraction force. The auxiliary Ca(2+) channel subunits alpha(2)delta-1 and beta(2) are important regulators of membrane expression and current properties of the cardiac Ca(2+) channel (Ca(V)1.2). However, their role in cardiac excitation-contraction coupling is still elusive. Here we addressed this question by combining siRNA knockdown of the alpha(2)delta-1 subunit in a muscle expression system with simulation of APs and Ca(2+) transients by using a quantitative computer model of ventricular myocytes. Reconstitution of dysgenic muscle cells with Ca(V)1.2 (GFP-alpha(1C)) recapitulates key properties of cardiac excitation-contraction coupling. Concomitant depletion of the alpha(2)delta-1 subunit did not perturb membrane expression or targeting of the pore-forming GFP-alpha(1C) subunit into junctions between the outer membrane and the sarcoplasmic reticulum. However, alpha(2)delta-1 depletion shifted the voltage dependence of Ca(2+) current activation by 9 mV to more positive potentials, and it slowed down activation and inactivation kinetics approximately 2-fold. Computer modeling revealed that the altered voltage dependence and current kinetics exert opposing effects on the function of ventricular myocytes that in total cause a 60% prolongation of the AP and a 2-fold increase of the myoplasmic Ca(2+) concentration during each contraction. Thus, the Ca(2+) channel alpha(2)delta-1 subunit is not essential for normal Ca(2+) channel targeting in muscle but is a key determinant of normal excitation and contraction of cardiac muscle cells, and a reduction of alpha(2)delta-1 function is predicted to severely perturb normal heart function.

  12. Characterization of enzymatic properties of human ribonucleotide reductase holoenzyme reconstituted in vitro from hRRM1, hRRM2, and p53R2 subunits.

    PubMed

    Qiu, Weihua; Zhou, Bingsen; Darwish, Dana; Shao, Jimin; Yen, Yun

    2006-02-10

    Ribonucleotide reductase (RR) is a highly regulated enzyme in the deoxyribonucleotide synthesis pathway. RR is responsible for the de novo conversion of ribonucleoside diphosphates to deoxyribonucleoside diphosphates, which are essential for DNA synthesis and repair. Besides two subunits, hRRM1 and hRRM2, p53R2 is a newly identified member of RR family that is induced by ultraviolet light in a p53-dependent manner. To understand the molecular interaction of RR subunits, we employed a eukaryotic expression system to express and purify all three subunits. After in vitro reconstitution, the results of [(3)H]CDP reduction assay showed that both eukaryotic recombinant hRRM2 and p53R2 proteins could interact with hRRM1 to form functional RR holoenzyme. The reconstituted RR activity was time-dependent and the reaction rate reached the plateau phase after 40min incubation. No matter the concentration, RR holoenzyme reconstituted from p53R2 and hRRM1 could only achieve about 40-75% kinetic activity of that from hRRM2 and hRRM1. The synthetic C-terminal heptapeptide competition assays confirmed that hRRM2 and p53R2 share the same binding site on hRRM1, but the binding site on hRRM1 demonstrated higher affinity for hRRM2 than for p53R2. In allosteric regulation assay, the effect of activation or inhibition of hRRM1 with ATP or dATP suggested that these effectors could regulate RR activity independent of different RR small subunits. Taken together, the eukaryotic expression system RR holoenzyme will provide a very useful tool to understand the molecular mechanisms of RR activity and the interactions of its subunits.

  13. 21 CFR 872.6010 - Abrasive device and accessories.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6010 Abrasive device and accessories... crowns. The device is attached to a shank that is held by a handpiece. The device includes the abrasive...

  14. 21 CFR 872.6010 - Abrasive device and accessories.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6010 Abrasive device and accessories... crowns. The device is attached to a shank that is held by a handpiece. The device includes the abrasive...

  15. 21 CFR 872.6010 - Abrasive device and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6010 Abrasive device and accessories... crowns. The device is attached to a shank that is held by a handpiece. The device includes the abrasive...

  16. 21 CFR 872.6010 - Abrasive device and accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6010 Abrasive device and accessories... crowns. The device is attached to a shank that is held by a handpiece. The device includes the abrasive...

  17. 21 CFR 872.6010 - Abrasive device and accessories.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6010 Abrasive device and accessories... crowns. The device is attached to a shank that is held by a handpiece. The device includes the abrasive...

  18. Weighing the evidence for a ternary protein complex mediating A-type K+ currents in neurons.

    PubMed

    Maffie, Jonathon; Rudy, Bernardo

    2008-12-01

    The subthreshold-operating A-type K(+) current in neurons (I(SA)) has important roles in the regulation of neuronal excitability, the timing of action potential firing and synaptic integration and plasticity. The channels mediating this current (Kv4 channels) have been implicated in epilepsy, the control of dopamine release, and the regulation of pain plasticity. It has been proposed that Kv4 channels in neurons are ternary complexes of three types of protein: pore forming subunits of the Kv4 subfamily and two types of auxiliary subunits, the Ca(2+) binding proteins KChIPs and the dipeptidyl peptidase-like proteins (DPPLs) DPP6 (also known as DPPX) and DPP10 (4 molecules of each per channel for a total of 12 proteins in the complex). Here we consider the evidence supporting this hypothesis. Kv4 channels in many neurons are likely to be ternary complexes of these three types of protein. KChIPs and DPPLs are required to efficiently traffic Kv4 channels to the plasma membrane and regulate the functional properties of the channels. These proteins may also be important in determining the localization of the channels to specific neuronal compartments, their dynamics, and their response to neuromodulators. A surprisingly large number of additional proteins have been shown to modify Kv4 channels in heterologous expression systems, but their association with native Kv4 channels in neurons has not been properly validated. A critical consideration of the evidence suggests that it is unlikely that association of Kv4 channels with these additional proteins is widespread in the CNS. However, we cannot exclude that some of these proteins may associate with the channels transiently or in specific neurons or neuronal compartments, or that they may associate with the channels in other tissues.

  19. Regulatory Subunit B′γ of Protein Phosphatase 2A Prevents Unnecessary Defense Reactions under Low Light in Arabidopsis1[W][OA

    PubMed Central

    Trotta, Andrea; Wrzaczek, Michael; Scharte, Judith; Tikkanen, Mikko; Konert, Grzegorz; Rahikainen, Moona; Holmström, Maija; Hiltunen, Hanna-Maija; Rips, Stephan; Sipari, Nina; Mulo, Paula; Weis, Engelbert; von Schaewen, Antje; Aro, Eva-Mari; Kangasjärvi, Saijaliisa

    2011-01-01

    Light is an important environmental factor that modulates acclimation strategies and defense responses in plants. We explored the functional role of the regulatory subunit B′γ (B′γ) of protein phosphatase 2A (PP2A) in light-dependent stress responses of Arabidopsis (Arabidopsis thaliana). The predominant form of PP2A consists of catalytic subunit C, scaffold subunit A, and highly variable regulatory subunit B, which determines the substrate specificity of PP2A holoenzymes. Mutant leaves of knockdown pp2a-b′γ plants show disintegration of chloroplasts and premature yellowing conditionally under moderate light intensity. The cell-death phenotype is accompanied by the accumulation of hydrogen peroxide through a pathway that requires CONSTITUTIVE EXPRESSION OF PR GENES5 (CPR5). Moreover, the pp2a-b′γ cpr5 double mutant additionally displays growth suppression and malformed trichomes. Similar to cpr5, the pp2a-b′γ mutant shows constitutive activation of both salicylic acid- and jasmonic acid-dependent defense pathways. In contrast to cpr5, however, pp2a-b′γ leaves do not contain increased levels of salicylic acid or jasmonic acid. Rather, the constitutive defense response associates with hypomethylation of DNA and increased levels of methionine-salvage pathway components in pp2a-b′γ leaves. We suggest that the specific B′γ subunit of PP2A is functionally connected to CPR5 and operates in the basal repression of defense responses under low irradiance. PMID:21571669

  20. γ-Aminobutyric Acid Type A α4, β2, and δ Subunits Assemble to Produce More Than One Functionally Distinct Receptor Type

    PubMed Central

    Eaton, Megan M.; Bracamontes, John; Shu, Hong-Jin; Li, Ping; Mennerick, Steven; Steinbach, Joe Henry

    2014-01-01

    Native γ-aminobutyric acid (GABA)A receptors consisting of α4, β1–3, and δ subunits mediate responses to the low, tonic concentration of GABA present in the extracellular milieu. Previous studies on heterologously expressed α4βδ receptors have shown a large degree of variability in functional properties, including sensitivity to the transmitter. We studied properties of α4β2δ receptors employing free subunits and concatemeric constructs, expressed in Xenopus oocytes, HEK 293 cells, and cultured hippocampal neurons. The expression system had a strong effect on the properties of receptors containing free subunits. The midpoint of GABA activation curve was 10 nM for receptors in oocytes versus 2300 nM in HEK cells. Receptors activated by the steroid alfaxalone had an estimated maximal open probability of 0.6 in oocytes and 0.01 in HEK cells. Irrespective of the expression system, receptors resulting from combining the tandem construct β2-δ and a free α4 subunit exhibited large steroid responses. We propose that free α4, β2, and δ subunits assemble in different configurations with distinct properties in oocytes and HEK cells, and that subunit linkage can overcome the expression system-dependent preferential assembly of free subunits. Hippocampal neurons transfected with α4 and the picrotoxin-resistant δ(T269Y) subunit showed large responses to alfaxalone in the presence of picrotoxin, suggesting that α4βδ receptors may assemble in a similar configuration in neurons and oocytes. PMID:25238745

  1. The NH2-terminal php domain of the alpha subunit of the Escherichia coli replicase binds the epsilon proofreading subunit.

    PubMed

    Wieczorek, Anna; McHenry, Charles S

    2006-05-05

    The alpha subunit of the replicase of all bacteria contains a php domain, initially identified by its similarity to histidinol phosphatase but of otherwise unknown function (Aravind, L., and Koonin, E. V. (1998) Nucleic Acids Res. 26, 3746-3752). Deletion of 60 residues from the NH2 terminus of the alpha php domain destroys epsilon binding. The minimal 255-residue php domain, estimated by sequence alignment with homolog YcdX, is insufficient for epsilon binding. However, a 320-residue segment including sequences that immediately precede the polymerase domain binds epsilon with the same affinity as the 1160-residue full-length alpha subunit. A subset of mutations of a conserved acidic residue (Asp43 in Escherichia coli alpha) present in the php domain of all bacterial replicases resulted in defects in epsilon binding. Using sequence alignments, we show that the prototypical gram+ Pol C, which contains the polymerase and proofreading activities within the same polypeptide chain, has an epsilon-like sequence inserted in a surface loop near the center of the homologous YcdX protein. These findings suggest that the php domain serves as a platform to enable coordination of proofreading and polymerase activities during chromosomal replication.

  2. Prefoldin Subunits Are Protected from Ubiquitin-Proteasome System-mediated Degradation by Forming Complex with Other Constituent Subunits*

    PubMed Central

    Miyazawa, Makoto; Tashiro, Erika; Kitaura, Hirotake; Maita, Hiroshi; Suto, Hiroo; Iguchi-Ariga, Sanae M. M.; Ariga, Hiroyoshi

    2011-01-01

    The molecular chaperone prefoldin (PFD) is a complex comprised of six different subunits, PFD1-PFD6, and delivers newly synthesized unfolded proteins to cytosolic chaperonin TRiC/CCT to facilitate the folding of proteins. PFD subunits also have functions different from the function of the PFD complex. We previously identified MM-1α/PFD5 as a novel c-Myc-binding protein and found that MM-1α suppresses transformation activity of c-Myc. However, it remains unclear how cells regulate protein levels of individual subunits and what mechanisms alter the ratio of their activities between subunits and their complex. In this study, we found that knockdown of one subunit decreased protein levels of other subunits and that transfection of five subunits other than MM-1α into cells increased the level of endogenous MM-1α. We also found that treatment of cells with MG132, a proteasome inhibitor, increased the level of transfected/overexpressed MM-1α but not that of endogenous MM-1α, indicating that overexpressed MM-1α, but not endogenous MM-1α, was degraded by the ubiquitin proteasome system (UPS). Experiments using other PFD subunits showed that the UPS degraded a monomer of PFD subunits, though extents of degradation varied among subunits. Furthermore, the level of one subunit was increased after co-transfection with the respective subunit, indicating that there are specific combinations between subunits to be stabilized. These results suggest mutual regulation of protein levels among PFD subunits and show how individual subunits form the PFD complex without degradation. PMID:21478150

  3. The Subunit Principle in Scar Face Revision.

    PubMed

    Elshahat, Ahmed; Lashin, Riham

    2017-06-01

    Facial scaring is considered one of the most difficult cosmetic problems for any plastic surgeon to solve. The condition is more difficult if the direction of the scar is not parallel to relaxed skin tension lines. Attempts to manage this difficult situation included revisions using geometric designs, Z plasties or W plasties to camouflage the straight line visible scaring. The use of long-lasting resorbable sutures was tried too. Recently, the use of botulinum toxin during revision improved the results. Fractional CO2 lasers, microfat grafts, and platelet-rich plasma were added to the armamentarium. The scar is least visible if placed in the junction between the facial subunits. The aim of this study is to investigate the use of the subunit principle to improve the results of scar revision. Four patients were included in this study. Tissue expansion of the intact part of the subunit allowed shifting the scar to the junction between the affected subunit and the adjacent one. Tissue expansion, delivery of the expanders, and advancement of the flaps were successful in all patients. The fact that this is a 2-stage procedure and sacrifices some of the intact skin from the affected facial subunit, makes this technique reserved to patients with ugly facial scars who are ambitious to improve their appearance.

  4. Algal Accessory Pigment Detection Using AVIRIS Image-Derived Spectral Radiance Data

    NASA Technical Reports Server (NTRS)

    Richardson, Laurie L.; Ambrosia, Vincent G.

    1996-01-01

    Visual and derivative analyses of AVIRIS spectral data can be used to detect algal accessory pigments in aquatic communities. This capability extends the use of remote sensing for the study of aquatic ecosystems by allowing detection of taxonomically significant pigment signatures which yield information about the type of algae present. Such information allows remote sensing-based assessment of aquatic ecosystem health, as in the detection of nuisance blooms of cyanobacteria or toxic blooms of dinoflagellates. Remote sensing of aquatic systems has traditionally focused on quantification of chlorophyll a, a photoreactive (and light-harvesting) pigment which is common to all algae as well as cyanobacteria (bluegreen algae). Due to the ubiquitousness of this pigment within algae, chl a is routinely measured to estimate algal biomass both during ground-truthing and using various airborne or satellite based sensors, including AVIRIS. Within the remote sensing and aquatic sciences communities, ongoing research has been performed to detect algal accessory pigments for assessment of algal population composition. This research is based on the fact that many algal accessory pigments are taxonomically significant, and all are spectrally unique. Aquatic scientists have been refining pigment analysis techniques, primarily high performance liquid chromatography, or HPLC, to detect specific pigments as a time-saving alternative to individual algal cell identifications and counts. Remote sensing scientists are investigating the use of pigment signatures to construct pigment libraries analogous to mineral spectral libraries used in geological remote sensing applications. The accessory pigment approach has been used successfully in remote sensing using data from the Thematic Mapper, low-altitude, multiple channel scanners, field spectroradiometers and the AVIRIS hyperspectral scanner. Due to spectral and spatial resolution capabilities, AVIRIS is the sensor of choice for such

  5. Suppressor mutations identify amino acids in PAA-1/PR65 that facilitate regulatory RSA-1/B″ subunit targeting of PP2A to centrosomes in C. elegans

    PubMed Central

    Lange, Karen I.; Heinrichs, Jeffrey; Cheung, Karen; Srayko, Martin

    2013-01-01

    Summary Protein phosphorylation and dephosphorylation is a key mechanism for the spatial and temporal regulation of many essential developmental processes and is especially prominent during mitosis. The multi-subunit protein phosphatase 2A (PP2A) enzyme plays an important, yet poorly characterized role in dephosphorylating proteins during mitosis. PP2As are heterotrimeric complexes comprising a catalytic, structural, and regulatory subunit. Regulatory subunits are mutually exclusive and determine subcellular localization and substrate specificity of PP2A. At least 3 different classes of regulatory subunits exist (termed B, B′, B″) but there is no obvious similarity in primary sequence between these classes. Therefore, it is not known how these diverse regulatory subunits interact with the same holoenzyme to facilitate specific PP2A functions in vivo. The B″ family of regulatory subunits is the least understood because these proteins lack conserved structural domains. RSA-1 (regulator of spindle assembly) is a regulatory B″ subunit required for mitotic spindle assembly in Caenorhabditis elegans. In order to address how B″ subunits interact with the PP2A core enzyme, we focused on a conditional allele, rsa-1(or598ts), and determined that this mutation specifically disrupts the protein interaction between RSA-1 and the PP2A structural subunit, PAA-1. Through genetic screening, we identified a putative interface on the PAA-1 structural subunit that interacts with a defined region of RSA-1/B″. In the context of previously published results, these data propose a mechanism of how different PP2A B-regulatory subunit families can bind the same holoenzyme in a mutually exclusive manner, to perform specific tasks in vivo. PMID:23336080

  6. Suppressor mutations identify amino acids in PAA-1/PR65 that facilitate regulatory RSA-1/B″ subunit targeting of PP2A to centrosomes in C. elegans.

    PubMed

    Lange, Karen I; Heinrichs, Jeffrey; Cheung, Karen; Srayko, Martin

    2013-01-15

    Protein phosphorylation and dephosphorylation is a key mechanism for the spatial and temporal regulation of many essential developmental processes and is especially prominent during mitosis. The multi-subunit protein phosphatase 2A (PP2A) enzyme plays an important, yet poorly characterized role in dephosphorylating proteins during mitosis. PP2As are heterotrimeric complexes comprising a catalytic, structural, and regulatory subunit. Regulatory subunits are mutually exclusive and determine subcellular localization and substrate specificity of PP2A. At least 3 different classes of regulatory subunits exist (termed B, B', B″) but there is no obvious similarity in primary sequence between these classes. Therefore, it is not known how these diverse regulatory subunits interact with the same holoenzyme to facilitate specific PP2A functions in vivo. The B″ family of regulatory subunits is the least understood because these proteins lack conserved structural domains. RSA-1 (regulator of spindle assembly) is a regulatory B″ subunit required for mitotic spindle assembly in Caenorhabditis elegans. In order to address how B″ subunits interact with the PP2A core enzyme, we focused on a conditional allele, rsa-1(or598ts), and determined that this mutation specifically disrupts the protein interaction between RSA-1 and the PP2A structural subunit, PAA-1. Through genetic screening, we identified a putative interface on the PAA-1 structural subunit that interacts with a defined region of RSA-1/B″. In the context of previously published results, these data propose a mechanism of how different PP2A B-regulatory subunit families can bind the same holoenzyme in a mutually exclusive manner, to perform specific tasks in vivo.

  7. Stimulatory and inhibitory effects of PKC isozymes are mediated by serine/threonine PKC sites of the Cav2.3α1 subunits.

    PubMed

    Rajagopal, Senthilkumar; Burton, Brittney K; Fields, Blanche L; El, India O; Kamatchi, Ganesan L

    2017-05-01

    Protein kinase C (PKC) isozymes modulate voltage-gated calcium (Ca v ) currents through Ca v 2.2 and Ca v 2.3 channels by targeting serine/threonine (Ser/Thr) phosphorylation sites of Ca v α 1 subunits. Stimulatory (Thr-422, Ser-2108 and Ser-2132) and inhibitory (Ser-425) sites were identified in the Ca v 2.2α 1 subunits to PKCs βII and ε. In the current study, we investigated if the homologous sites of Ca v 2.3α 1 subunits (stimulatory: Thr-365, Ser-1995 and Ser-2011; inhibitory: Ser-369) behaved in similar manner. Several Ala and Asp mutants were constructed in Ca v 2.3α 1 subunits in such a way that the Ser/Thr sites can be examined in isolation. These mutants or WT Ca v 2.3α 1 along with auxiliary β 1b and α 2subunits were expressed in Xenopus oocytes and the effects of PKCs βII and ε studied on the barium current (I Ba ). Among these sites, stimulatory Thr-365 and Ser-1995 and inhibitory Ser-369 behaved similar to their homologs in Ca v 2.2α 1 subunits. Furthermore PKCs produced neither stimulation nor inhibition when stimulatory Thr-365 or Ser-1995 and inhibitory Ser-369 were present together. However, the PKCs potentiated the I Ba when two stimulatory sites, Thr-365 and Ser-1995 were present together, thus overcoming the inhibitory effect of Ser-369. Taken together net PKC effect may be the difference between the responses of the stimulatory and inhibitory sites. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. 49 CFR 390.17 - Additional equipment and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... equipment and accessories, not inconsistent with or prohibited by this subchapter, provided such equipment... are used. [53 FR 18052, May 19, 1988, as amended at 60 FR 38744, July 28, 1995. Redesignated at 65 FR...

  9. Functional organization of glomerular maps in the mouse accessory olfactory bulb

    PubMed Central

    Hammen, Gary F.; Turaga, Diwakar; Holy, Timothy E.; Meeks, Julian P.

    2014-01-01

    Summary The mammalian accessory olfactory system (AOS) extracts information about species, sex, and individual identity from social odors, but its functional organization remains unclear. We imaged presynaptic Ca2+ signals in vomeronasal inputs to the accessory olfactory bulb (AOB) during peripheral stimulation using light sheet microscopy. Urine- and steroid-responsive glomeruli densely innervated the anterior AOB. Glomerular activity maps for sexually mature female mouse urine overlapped maps for juvenile and/or gonadectomized urine of both sexes, whereas maps for sexually mature male urine were highly distinct. Further spatial analysis revealed a complicated organization involving selective juxtaposition and dispersal of functionally-grouped glomerular classes. Glomeruli that were similarly tuned to urines were often closely associated, whereas more disparately tuned glomeruli were selectively dispersed. Maps to a panel of sulfated steroid odorants identified tightly-juxtaposed groups that were disparately tuned and dispersed groups that were similarly tuned. These results reveal a modular, non-chemotopic spatial organization in the AOB. PMID:24880215

  10. The nucleotide composition of microbial genomes indicates differential patterns of selection on core and accessory genomes.

    PubMed

    Bohlin, Jon; Eldholm, Vegard; Pettersson, John H O; Brynildsrud, Ola; Snipen, Lars

    2017-02-10

    The core genome consists of genes shared by the vast majority of a species and is therefore assumed to have been subjected to substantially stronger purifying selection than the more mobile elements of the genome, also known as the accessory genome. Here we examine intragenic base composition differences in core genomes and corresponding accessory genomes in 36 species, represented by the genomes of 731 bacterial strains, to assess the impact of selective forces on base composition in microbes. We also explore, in turn, how these results compare with findings for whole genome intragenic regions. We found that GC content in coding regions is significantly higher in core genomes than accessory genomes and whole genomes. Likewise, GC content variation within coding regions was significantly lower in core genomes than in accessory genomes and whole genomes. Relative entropy in coding regions, measured as the difference between observed and expected trinucleotide frequencies estimated from mononucleotide frequencies, was significantly higher in the core genomes than in accessory and whole genomes. Relative entropy was positively associated with coding region GC content within the accessory genomes, but not within the corresponding coding regions of core or whole genomes. The higher intragenic GC content and relative entropy, as well as the lower GC content variation, observed in the core genomes is most likely associated with selective constraints. It is unclear whether the positive association between GC content and relative entropy in the more mobile accessory genomes constitutes signatures of selection or selective neutral processes.

  11. In silico predictions of LH2 ring sizes from the crystal structure of a single subunit using molecular dynamics simulations.

    PubMed

    Janosi, Lorant; Keer, Harindar; Cogdell, Richard J; Ritz, Thorsten; Kosztin, Ioan

    2011-07-01

    Most of the currently known light-harvesting complexes 2 (LH2) rings are formed by 8 or 9 subunits. As of now, questions like "what factors govern the LH2 ring size?" and "are there other ring sizes possible?" remain largely unanswered. Here, we investigate by means of molecular dynamics (MD) simulations and stochastic modeling the possibility of predicting the size of an LH2 ring from the sole knowledge of the high resolution crystal structure of a single subunit. Starting with single subunits of two LH2 rings with known size, that is, an 8-ring from Rs. moliscianum (MOLI) and a 9-ring from Rps. acidophila (ACI), and one with unknown size (referred to as X), we build atomic models of subunit dimers corresponding to assumed 8-, 9-, and 10-ring geometries. After inserting each of the dimers into a lipid-water environment, we determine the preferred angle between the corresponding subunits by three methods: (1) energy minimization, (2) free MD simulations, and (3) potential of mean force calculations. We find that the results from all three methods are consistent with each other, and when taken together, it allows one to predict with reasonable level of confidence the sizes of the corresponding ring structures. One finds that X and ACI very likely form a 9-ring, while MOLI is more likely to form an 8-ring than a 9-ring. Finally, we discuss both the merits and limitations of all three prediction methods. Copyright © 2011 Wiley-Liss, Inc.

  12. DNA sequences, recombinant DNA molecules and processes for producing the A and B subunits of cholera toxin and preparations containing so-obtained subunit or subunits

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Harford, N.; De Wilde, M.

    1987-05-19

    A recombinant DNA molecule is described comprising at least a portion coding for subunits A and B of cholera toxin, or a fragment or derivative of the portion wherein the fragment or derivative codes for a polypeptide have an activity which can induce an immune response to subunit A; can induce an immune response to subunit A and cause epithelial cell penetration and the enzymatic effect leading to net loss of fluid into the gut lumen; can bind to the membrane receptor for the B subunit of cholera toxin; can induce an immune response to subunit B; can induce anmore » immune response to subunit B and bind to the membrane receptor; or has a combination of the activities.« less

  13. Sodium Channel β2 Subunits Prevent Action Potential Propagation Failures at Axonal Branch Points.

    PubMed

    Cho, In Ha; Panzera, Lauren C; Chin, Morven; Hoppa, Michael B

    2017-09-27

    Neurotransmitter release depends on voltage-gated Na + channels (Na v s) to propagate an action potential (AP) successfully from the axon hillock to a synaptic terminal. Unmyelinated sections of axon are very diverse structures encompassing branch points and numerous presynaptic terminals with undefined molecular partners of Na + channels. Using optical recordings of Ca 2+ and membrane voltage, we demonstrate here that Na + channel β2 subunits (Na v β2s) are required to prevent AP propagation failures across the axonal arborization of cultured rat hippocampal neurons (mixed male and female). When Na v β2 expression was reduced, we identified two specific phenotypes: (1) membrane excitability and AP-evoked Ca 2+ entry were impaired at synapses and (2) AP propagation was severely compromised with >40% of axonal branches no longer responding to AP-stimulation. We went on to show that a great deal of electrical signaling heterogeneity exists in AP waveforms across the axonal arborization independent of axon morphology. Therefore, Na v β2 is a critical regulator of axonal excitability and synaptic function in unmyelinated axons. SIGNIFICANCE STATEMENT Voltage-gated Ca 2+ channels are fulcrums of neurotransmission that convert electrical inputs into chemical outputs in the form of vesicle fusion at synaptic terminals. However, the role of the electrical signal, the presynaptic action potential (AP), in modulating synaptic transmission is less clear. What is the fidelity of a propagating AP waveform in the axon and what molecules shape it throughout the axonal arborization? Our work identifies several new features of AP propagation in unmyelinated axons: (1) branches of a single axonal arborization have variable AP waveforms independent of morphology, (2) Na + channel β2 subunits modulate AP-evoked Ca 2+ -influx, and (3) β2 subunits maintain successful AP propagation across the axonal arbor. These findings are relevant to understanding the flow of excitation in the

  14. 21 CFR 876.4300 - Endoscopic electrosurgical unit and accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... accessories is a device used to perform electrosurgical procedures through an endoscope. This generic type of device includes the electrosurgical generator, patient plate, electric biopsy forceps, electrode...

  15. Mutations in the PP2A regulatory subunit B family genes PPP2R5B, PPP2R5C and PPP2R5D cause human overgrowth.

    PubMed

    Loveday, Chey; Tatton-Brown, Katrina; Clarke, Matthew; Westwood, Isaac; Renwick, Anthony; Ramsay, Emma; Nemeth, Andrea; Campbell, Jennifer; Joss, Shelagh; Gardner, McKinlay; Zachariou, Anna; Elliott, Anna; Ruark, Elise; van Montfort, Rob; Rahman, Nazneen

    2015-09-01

    Overgrowth syndromes comprise a group of heterogeneous disorders characterised by excessive growth parameters, often in association with intellectual disability. To identify new causes of human overgrowth, we have been undertaking trio-based exome sequencing studies in overgrowth patients and their unaffected parents. Prioritisation of functionally relevant genes with multiple unique de novo mutations revealed four mutations in protein phosphatase 2A (PP2A) regulatory subunit B family genes protein phosphatase 2, regulatory Subunit B', beta (PPP2R5B); protein phosphatase 2, regulatory Subunit B', gamma (PPP2R5C); and protein phosphatase 2, regulatory Subunit B', delta (PPP2R5D). This observation in 3 related genes in 111 individuals with a similar phenotype is greatly in excess of the expected number, as determined from gene-specific de novo mutation rates (P = 1.43 × 10(-10)). Analysis of exome-sequencing data from a follow-up series of overgrowth probands identified a further pathogenic mutation, bringing the total number of affected individuals to 5. Heterozygotes shared similar phenotypic features including increased height, increased head circumference and intellectual disability. The mutations clustered within a region of nine amino acid residues in the aligned protein sequences (P = 1.6 × 10(-5)). We mapped the mutations onto the crystal structure of the PP2A holoenzyme complex to predict their molecular and functional consequences. These studies suggest that the mutations may affect substrate binding, thus perturbing the ability of PP2A to dephosphorylate particular protein substrates. PP2A is a major negative regulator of v-akt murine thymoma viral oncogene homolog 1 (AKT). Thus, our data further expand the list of genes encoding components of the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/AKT signalling cascade that are disrupted in human overgrowth conditions. © The Author 2015. Published by Oxford University Press.

  16. Propofol effectively inhibits lithium-pilocarpine- induced status epilepticus in rats via downregulation of N-methyl-D-aspartate receptor 2B subunit expression

    PubMed Central

    Wang, Henglin; Wang, Zhuoqiang; Mi, Weidong; Zhao, Cong; Liu, Yanqin; Wang, Yongan; Sun, Haipeng

    2012-01-01

    Status epilepticus was induced via intraperitoneal injection of lithium-pilocarpine. The inhibitory effects of propofol on status epilepticus in rats were judged based on observation of behavior, electroencephalography and 24-hour survival rate. Propofol (12.5–100 mg/kg) improved status epilepticus in a dose-dependent manner, and significantly reduced the number of deaths within 24 hours of lithium-pilocarpine injection. Western blot results showed that, 24 hours after induction of status epilepticus, the levels of N-methyl-D-aspartate receptor 2A and 2B subunits were significantly increased in rat cerebral cortex and hippocampus. Propofol at 50 mg/kg significantly suppressed the increase in N-methyl-D-aspartate receptor 2B subunit levels, but not the increase in N-methyl-D-aspartate receptor 2A subunit levels. The results suggest that propofol can effectively inhibit status epilepticus induced by lithium-pilocarpine. This effect may be associated with downregulation of N-methyl-D-aspartate receptor 2B subunit expression after seizures. PMID:25737709

  17. Soybean glycinin subunits: Characterization of physicochemical and adhesion properties.

    PubMed

    Mo, Xiaoqun; Zhong, Zhikai; Wang, Donghai; Sun, Xiuzhi

    2006-10-04

    Soybean proteins have shown great potential for applications as renewable and environmentally friendly adhesives. The objective of this work was to study physicochemical and adhesion properties of soy glycinin subunits. Soybean glycinin was extracted from soybean flour and then fractionated into acidic and basic subunits with an estimated purity of 90 and 85%, respectively. Amino acid composition of glycinin subunits was determined. The high hydrophobic amino acid content is a major contributor to the solubility behavior and water resistance of the basic subunits. Acidic subunits and glycinin had similar solubility profiles, showing more than 80% solubility at pH 2.0-4.0 or 6.5-12.0, whereas basic subunits had considerably lower solubility with the minimum at pH 4.5-8.0. Thermal analysis using a differential scanning calorimeter suggested that basic subunits form new oligomeric structures with higher thermal stability than glycinin but no highly ordered structures present in isolated acidic subunits. The wet strength of basic subunits was 160% more than that of acidic subunits prepared at their respective isoelectric points (pI) and cured at 130 degrees C. Both pH and the curing temperature significantly affected adhesive performance. High-adhesion water resistance was usually observed for adhesives from protein prepared at their pI values and cured at elevated temperatures. Basic subunits are responsible for the water resistance of glycinin and are a good starting material for the development of water-resistant adhesives.

  18. The scolopidial accessory organs and Nebenorgans in orthopteroid insects: Comparative neuroanatomy, mechanosensory function, and evolutionary origin.

    PubMed

    Strauß, Johannes

    2017-11-01

    Scolopidial sensilla in insects often form large sensory organs involved in proprioception or exteroception. Here the knowledge on Nebenorgans and accessory organs, two organs consisting of scolopidial sensory cells, is summarised. These organs are present in some insects which are model organisms for the physiology of mechanosensory systems (cockroaches and tettigoniids). Recent comparative studies documented the accessory organ in several taxa of Orthoptera (including tettigoniids, cave crickets, Jerusalem crickets) and the Nebenorgan in related insects (Mantophasmatodea). The accessory organ or Nebenorgan is usually a small organ of 8-15 sensilla located in the posterior leg tibia of all leg pairs. The physiological properties of the accessory organs and Nebenorgans are so far largely unknown. Taking together neuroanatomical and electrophysiological data from disparate taxa, there is considerable evidence that the accessory organ and Nebenorgan are vibrosensitive. They thus complement the larger vibrosensitive subgenual organ in the tibia. This review summarises the comparative studies of these sensory organs, in particular the arguments and criteria for the homology of the accessory organ and Nebenorgan among orthopteroid insects. Different scenarios of repeated evolutionary origins or losses of these sensory organs are discussed. Neuroanatomy allows to distinguish individual sensory organs for analysis of sensory physiology, and to infer scenarios of sensory evolution. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Accessories modifying based on plastic waste of shampoo bottle as home economic product

    NASA Astrophysics Data System (ADS)

    Setyowati, Erna; Sukesi, Siti

    2018-03-01

    Plastic is a waste that can not decompose by the soil and if its left without a good handling can pollute the environment. Plastic waste needs processing by the recycle bottles principle. Shampoo bottle is one of plastic waste with high density polyethylene type (HDPE). One of the innovation to recycling shampoo bottles waste into the new products whichbeneficially and aestheticallyform by engineered the buns accesories. Accessories are one of the tools used by most women, in the form of trinkets or ornaments which ajusted to the trend to beautify the look. Accessories from shampoo bottle waste can be obtained from household waste, beauty salon and the beauty program study by inculcating human beings' behavior by transforming waste into blessing while also increasing family income. Technique of making its by compiling through improvement of panelist team. The goal of this research is to engineering theaccessories based on shampoo bottle waste as home economics. The method are using experiment, observation and documentation, analysis using descriptive. The results obtained from the overall sensory test averaged at 93%, while the favored test averaged at 85.5%. The product can be ordered according to the desired design, but it takes a long time. Therefore accessories engineering from shampoo bottles waste-based can be used as home economics. The production of shampoo bottles waste-based accessories should improved its quality and quantity, to be marketed through the community, by the cooperation with accessories and bun craftsmen.

  20. The V-ATPase a2-subunit as a putative endosomal pH-sensor.

    PubMed

    Marshansky, V

    2007-11-01

    V-ATPase (vesicular H(+)-ATPase)-driven intravesicular acidification is crucial for vesicular trafficking. Defects in vesicular acidification and trafficking have recently been recognized as essential determinants of various human diseases. An important role of endosomal acidification in receptor-ligand dissociation and in activation of lysosomal hydrolytic enzymes is well established. However, the molecular mechanisms by which luminal pH information is transmitted to the cytosolic small GTPases that control trafficking events such as budding, coat formation and fusion are unknown. Here, we discuss our recent discovery that endosomal V-ATPase is a pH-sensor regulating the degradative pathway. According to our model, V-ATPase is responsible for: (i) the generation of a pH gradient between vesicular membranes; (ii) sensing of intravesicular pH; and (iii) transmitting this information to the cytosolic side of the membrane. We also propose the hypothetical molecular mechanism involved in function of the V-ATPase a2-subunit as a putative pH-sensor. Based on extensive experimental evidence on the crucial role of histidine residues in the function of PSPs (pH-sensing proteins) in eukaryotic cells, we hypothesize that pH-sensitive histidine residues within the intra-endosomal loops and/or C-terminal luminal tail of the a2-subunit could also be involved in the pH-sensing function of V-ATPase. However, in order to identify putative pH-sensitive histidine residues and to test this hypothesis, it is absolutely essential that we increase our understanding of the folding and transmembrane topology of the a-subunit isoforms of V-ATPase. Thus the crucial role of intra-endosomal histidine residues in pH-dependent conformational changes of the V-ATPase a2-isoform, its interaction with cytosolic small GTPases and ultimately in its acidification-dependent regulation of the endosomal/lysosomal protein degradative pathway remain to be determined.

  1. 21 CFR 884.1690 - Hysteroscope and accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... specialized instrument or device delivery system; do not have adapters, connectors, channels, or do not have... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hysteroscope and accessories. 884.1690 Section 884.1690 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED...

  2. 21 CFR 884.1690 - Hysteroscope and accessories.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... specialized instrument or device delivery system; do not have adapters, connectors, channels, or do not have... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Hysteroscope and accessories. 884.1690 Section 884.1690 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED...

  3. 21 CFR 884.1690 - Hysteroscope and accessories.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... specialized instrument or device delivery system; do not have adapters, connectors, channels, or do not have... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Hysteroscope and accessories. 884.1690 Section 884.1690 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED...

  4. 21 CFR 884.1690 - Hysteroscope and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... specialized instrument or device delivery system; do not have adapters, connectors, channels, or do not have... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hysteroscope and accessories. 884.1690 Section 884.1690 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED...

  5. 21 CFR 884.1690 - Hysteroscope and accessories.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... specialized instrument or device delivery system; do not have adapters, connectors, channels, or do not have... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hysteroscope and accessories. 884.1690 Section 884.1690 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED...

  6. Progress in the clinical imaging research of bone diseases on ankle and foot sesamoid bones and accessory ossicles

    PubMed Central

    Li, Xiaozhong; Shi, Lenian; Liu, Taiyun; Wang, Lin

    2012-01-01

    Summary Sesamoid bones and accessory ossicles are research focuses of foot and ankle surgery. Pains of the foot and ankle are related to sesamoid bones and accessory ossicles. The specific anatomical and functional relationship of sesamoid bones and accessory ossicles can cause such bone diseases as the dislocation of sesamoid bones and accessory bones, infection, inflammation and necrosis of sesamoid bones, cartilage softening, tenosynovitis of sesamoid bones and the sesamoid bone syndrome. However, these bone diseases are often misdiagnosed or mistreated. In patients with trauma history, relevant diseases of sesamoid bones and accessory ossicles as above mentioned are highly probable to be misdiagnosed as avulsion fractures. In such cases, radiographic findings may provide a basis for clinical diagnosis. PMID:25343083

  7. Adrenocorticotropic Hormone (ACTH) Responses Require Actions of the Melanocortin-2 Receptor Accessory Protein on the Extracellular Surface of the Plasma Membrane.

    PubMed

    Malik, Sundeep; Dolan, Terrance M; Maben, Zachary J; Hinkle, Patricia M

    2015-11-13

    The melanocortin-2 (MC2) receptor is a G protein-coupled receptor that mediates responses to ACTH. The MC2 receptor acts in concert with the MC2 receptor accessory protein (MRAP) that is absolutely required for ACTH binding and signaling. MRAP has a single transmembrane domain and forms a highly unusual antiparallel homodimer that is stably associated with MC2 receptors at the plasma membrane. Despite the physiological importance of the interaction between the MC2 receptor and MRAP, there is little understanding of how the accessory protein works. The dual topology of MRAP has made it impossible to determine whether highly conserved and necessary regions of MRAP are required on the intracellular or extracellular face of the plasma membrane. The strategy used here was to fix the orientation of two antiparallel MRAP molecules and then introduce inactivating mutations on one side of the membrane or the other. This was achieved by engineering proteins containing tandem copies of MRAP fused to the amino terminus of the MC2 receptor. The data firmly establish that only the extracellular amino terminus (Nout) copy of MRAP, oriented with critical segments on the extracellular side of the membrane, is essential. The transmembrane domain of MRAP is also required in only the Nout orientation. Finally, activity of MRAP-MRAP-MC2-receptor fusion proteins with inactivating mutations in either MRAP or the receptor was rescued by co-expression of free wild-type MRAP or free wild-type receptor. These results show that the basic MRAP-MRAP-receptor signaling unit forms higher order complexes and that these multimers signal. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  8. 26 CFR 48.4061(b)-3 - Rebuilt, reconditioned, or repaired parts or accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ..., Tires, Tubes, Tread Rubber, and Taxable Fuel Automotive and Related Items § 48.4061(b)-3 Rebuilt... batteries, (2) rebabbited or machined connecting rods, (3) reassembled clutches after operations such as the... reassembling (with any necessary replacements of worn parts) of automobile parts or accessories, such as fuel...

  9. FXYD2, a γ subunit of Na+,K+-ATPase, maintains persistent mechanical allodynia induced by inflammation

    PubMed Central

    Wang, Feng; Cai, Bing; Li, Kai-Cheng; Hu, Xu-Ye; Lu, Ying-Jin; Wang, Qiong; Bao, Lan; Zhang, Xu

    2015-01-01

    Na+,K+-ATPase (NKA) is required to generate the resting membrane potential in neurons. Nociceptive afferent neurons express not only the α and β subunits of NKA but also the γ subunit FXYD2. However, the neural function of FXYD2 is unknown. The present study shows that FXYD2 in nociceptive neurons is necessary for maintaining the mechanical allodynia induced by peripheral inflammation. FXYD2 interacted with α1NKA and negatively regulated the NKA activity, depolarizing the membrane potential of nociceptive neurons. Mechanical allodynia initiated in FXYD2-deficient mice was abolished 4 days after inflammation, whereas it persisted for at least 3 weeks in wild-type mice. Importantly, the FXYD2/α1NKA interaction gradually increased after inflammation and peaked on day 4 post inflammation, resulting in reduction of NKA activity, depolarization of neuron membrane and facilitation of excitatory afferent neurotransmission. Thus, the increased FXYD2 activity may be a fundamental mechanism underlying the persistent hypersensitivity to pain induced by inflammation. PMID:25633594

  10. 77 FR 22802 - Certain Handbags, Luggage, Accessories, and Packaging Thereof; Determination Not To Review an...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-17

    ... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-754] Certain Handbags, Luggage, Accessories, and Packaging Thereof; Determination Not To Review an Initial Determination Granting Complainant... importation of certain handbags, luggage, accessories, and packaging thereof by reason of infringement of U.S...

  11. Three-dimensional finite element analysis on canine teeth distalization by different accessories of bracket-free invisible orthodontics technology

    NASA Astrophysics Data System (ADS)

    Xu, Nuo; Lei, Xue; Yang, Xiaoli; Li, Xinhui; Ge, Zhenlin

    2018-04-01

    Objective: to compare canine tooth stress distribution condition during maxillary canine tooth distalization by different accessories of bracket-free invisible orthodontics technology after removal of maxillary first premolar, and provide basis for clinical design of invisible orthodontics technology. Method: CBCT scanning image of a patient with individual normal occlusion was adopted, Mimics, Geomagic and ProlE software were used for establishing three-dimensional models of maxilla, maxillary dentition, parodontium, invisible orthodontics appliance and accessories, ANSYS WORKBENCH was utilized as finite element analysis tools for analyzing stress distribution and movement pattern of canine tooth and parodontium when canine tooth was equipped with power arm and vertical rectangle accessory. Meanwhile, canine tooth none-accessory design group was regarded as a control. Result: teeth had even bistal surface stress distribution in the power arm group; stress was concentrated on distal tooth neck, and the stress was gradually deviated to mesial-labial side and distal lingual side in vertical rectangle group and none-accessory group. Conclusion: teeth tend to move as a whole in the Power arm group, vertical rectangle group has lower tooth gradient compared with the none-accessory group, teeth are inclined for movement in the none-accessory group, and canine teeth tend to rotate to the distal lingual side.

  12. Mechanisms of the gabapentinoids and α 2 δ-1 calcium channel subunit in neuropathic pain.

    PubMed

    Patel, Ryan; Dickenson, Anthony H

    2016-04-01

    The gabapentinoid drugs gabapentin and pregabalin are key front-line therapies for various neuropathies of peripheral and central origin. Originally designed as analogs of GABA, the gabapentinoids bind to the α 2 δ-1 and α 2 δ-2 auxiliary subunits of calcium channels, though only the former has been implicated in the development of neuropathy in animal models. Transgenic approaches also identify α 2 δ-1 as key in mediating the analgesic effects of gabapentinoids, however the precise molecular mechanisms remain unclear. Here we review the current understanding of the pathophysiological role of the α 2 δ-1 subunit, the mechanisms of analgesic action of gabapentinoid drugs and implications for efficacy in the clinic. Despite widespread use, the number needed to treat for gabapentin and pregabalin averages from 3 to 8 across neuropathies. The failure to treat large numbers of patients adequately necessitates a novel approach to treatment selection. Stratifying patients by sensory profiles may imply common underlying mechanisms, and a greater understanding of these mechanisms could lead to more direct targeting of gabapentinoids.

  13. Accessory genes confer a high replication rate to virulent feline immunodeficiency virus.

    PubMed

    Troyer, Ryan M; Thompson, Jesse; Elder, John H; VandeWoude, Sue

    2013-07-01

    Feline immunodeficiency virus (FIV) is a lentivirus that causes AIDS in domestic cats, similar to human immunodeficiency virus (HIV)/AIDS in humans. The FIV accessory protein Vif abrogates the inhibition of infection by cat APOBEC3 restriction factors. FIV also encodes a multifunctional OrfA accessory protein that has characteristics similar to HIV Tat, Vpu, Vpr, and Nef. To examine the role of vif and orfA accessory genes in FIV replication and pathogenicity, we generated chimeras between two FIV molecular clones with divergent disease potentials: a highly pathogenic isolate that replicates rapidly in vitro and is associated with significant immunopathology in vivo, FIV-C36 (referred to here as high-virulence FIV [HV-FIV]), and a less-pathogenic strain, FIV-PPR (referred to here as low-virulence FIV [LV-FIV]). Using PCR-driven overlap extension, we produced viruses in which vif, orfA, or both genes from virulent HV-FIV replaced equivalent genes in LV-FIV. The generation of these chimeras is more straightforward in FIV than in primate lentiviruses, since FIV accessory gene open reading frames have very little overlap with other genes. All three chimeric viruses exhibited increased replication kinetics in vitro compared to the replication kinetics of LV-FIV. Chimeras containing HV-Vif or Vif/OrfA had replication rates equivalent to those of the virulent HV-FIV parental virus. Furthermore, small interfering RNA knockdown of feline APOBEC3 genes resulted in equalization of replication rates between LV-FIV and LV-FIV encoding HV-FIV Vif. These findings demonstrate that Vif-APOBEC interactions play a key role in controlling the replication and pathogenicity of this immunodeficiency-inducing virus in its native host species and that accessory genes act as mediators of lentiviral strain-specific virulence.

  14. Regulation of leaf organ size by the Arabidopsis RPT2a 19S proteasome subunit.

    PubMed

    Sonoda, Yutaka; Sako, Kaori; Maki, Yuko; Yamazaki, Naoko; Yamamoto, Hiroko; Ikeda, Akira; Yamaguchi, Junji

    2009-10-01

    The ubiquitin/26S proteasome pathway plays a central role in the degradation of short-lived regulatory proteins, to control many cellular events. To further understand this pathway, we focused on the RPT2 subunit of the 26S proteasome regulatory particle. The Arabidopsis genome contains two genes, AtRPT2a and AtRPT2b, which encode paralog molecules of the RPT2 subunit, with a difference of only three amino acids in the protein sequences. Both genes showed similar mRNA accumulation patterns. However, the rpt2a mutant showed a specific phenotype of enlarged leaves caused by increased cell size, in correlation with increased ploidy. Detailed analyses revealed that cell expansion is increased in the rpt2a mutant by extended endoreduplication early in leaf development. The transcription of genes encoding cell cycle-related components, for DNA replication licensing and the G2/M phase, was also promoted in the rpt2a mutant, suggesting that extended endoreduplication was caused by increased DNA replication, and disrupted regulation of the G2/M checkpoint, at the proliferation stage of leaf development.

  15. N terminus of Swr1 binds to histone H2AZ and provides a platform for subunit assembly in the chromatin remodeling complex.

    PubMed

    Wu, Wei-Hua; Wu, Chwen-Huey; Ladurner, Andreas; Mizuguchi, Gaku; Wei, Debbie; Xiao, Hua; Luk, Ed; Ranjan, Anand; Wu, Carl

    2009-03-06

    Variant histone H2AZ-containing nucleosomes are involved in the regulation of gene expression. In Saccharomyces cerevisiae, chromatin deposition of histone H2AZ is mediated by the fourteen-subunit SWR1 complex, which catalyzes ATP-dependent exchange of nucleosomal histone H2A for H2AZ. Previous work defined the role of seven SWR1 subunits (Swr1 ATPase, Swc2, Swc3, Arp6, Swc5, Yaf9, and Swc6) in maintaining complex integrity and H2AZ histone replacement activity. Here we examined the function of three additional SWR1 subunits, bromodomain containing Bdf1, actin-related protein Arp4 and Swc7, by analyzing affinity-purified mutant SWR1 complexes. We observed that depletion of Arp4 (arp4-td) substantially impaired the association of Bdf1, Yaf9, and Swc4. In contrast, loss of either Bdf1 or Swc7 had minimal effects on overall complex integrity. Furthermore, the basic H2AZ histone replacement activity of SWR1 in vitro required Arp4, but not Bdf1 or Swc7. Thus, three out of fourteen SWR1 subunits, Bdf1, Swc7, and previously noted Swc3, appear to have roles auxiliary to the basic histone replacement activity. The N-terminal region of the Swr1 ATPase subunit is necessary and sufficient to direct association of Bdf1 and Swc7, as well as Arp4, Act1, Yaf9 and Swc4. This same region contains an additional H2AZ-H2B specific binding site, distinct from the previously identified Swc2 subunit. These findings suggest that one SWR1 enzyme might be capable of binding two H2AZ-H2B dimers, and provide further insight on the hierarchy and interdependency of molecular interactions within the SWR1 complex.

  16. The β and γ subunits play distinct functional roles in the α2βγ heterotetramer of human NAD-dependent isocitrate dehydrogenase

    NASA Astrophysics Data System (ADS)

    Ma, Tengfei; Peng, Yingjie; Huang, Wei; Liu, Yabing; Ding, Jianping

    2017-01-01

    Human NAD-dependent isocitrate dehydrogenase existing as the α2βγ heterotetramer, catalyzes the decarboxylation of isocitrate into α-ketoglutarate in the Krebs cycle, and is allosterically regulated by citrate, ADP and ATP. To explore the functional roles of the regulatory β and γ subunits, we systematically characterized the enzymatic properties of the holoenzyme and the composing αβ and αγ heterodimers in the absence and presence of regulators. The biochemical and mutagenesis data show that αβ and αγ alone have considerable basal activity but the full activity of α2βγ requires the assembly and cooperative function of both heterodimers. α2βγ and αγ can be activated by citrate or/and ADP, whereas αβ cannot. The binding of citrate or/and ADP decreases the S0.5,isocitrate and thus enhances the catalytic efficiencies of the enzymes, and the two activators can act independently or synergistically. Moreover, ATP can activate α2βγ and αγ at low concentration and inhibit the enzymes at high concentration, but has only inhibitory effect on αβ. Furthermore, the allosteric activation of α2βγ is through the γ subunit not the β subunit. These results demonstrate that the γ subunit plays regulatory role to activate the holoenzyme, and the β subunit the structural role to facilitate the assembly of the holoenzyme.

  17. Single channel properties of human α3 AChRs: impact of β2, β4 and α5 subunits

    PubMed Central

    Nelson, Mark E; Lindstrom, Jon

    1999-01-01

    We performed single channel analysis on human α3 acetylcholine receptors (AChRs) in Xenopus oocytes and native AChRs from the human neuroblastoma cell line IMR-32. α3 AChRs exhibit channel properties that reflect subunit composition.α3β2 AChR open times were 0.71 ± 0.14 and 3.5 ± 0.4 ms with a predominant conductance of 26 pS. α3β4 AChRs had open times of 1.4 ± 0.2 and 6.5 ± 0.8 ms and a predominant conductance of 31 pS. Burst times were 0.82 ± 0.12 and 5.3 ± 0.7 ms for α3β2 and 1.7 ± 0.1 and 16 ± 1 ms for α3β4. Desensitization was faster for AChRs with the β2 subunit than for those with the β4 subunit.One open time for α3α5β2 AChRs (5.5 ± 0.3 ms) was different from those of α3β2 AChRs. For α3α5β4 AChRs, an additional conductance, open time and burst time (36 pS, 22 ± 3 ms and 43 ± 4 ms, respectively) were different from those for α3β4 AChRs.α3 AChRs were inhibited by hexamethonium or mecamylamine. The rate constants for block of α3β4 by hexamethonium and of α3β2 by mecamylamine were 1.2 × 107 and 4.6 × 107 M−1 s−1, respectively.AChRs from IMR-32 cells had a predominant conductance of 32 pS and open times of 1.5 ± 0.3 and 9.6 ± 1.2 ms. These properties were most similar to those of α3β4 AChRs expressed in oocytes. Antibodies revealed that 5 ± 2% of IMR-32 α3 AChRs contained α5 subunits and 6 ± 2% contained β2 subunits. IMR-32 α3 AChRs are primarily α3β4 AChRs. PMID:10200416

  18. Rubisco oligomers composed of linked small and large subunits assemble in tobacco plastids and have higher affinities for CO2 and O2.

    PubMed

    Whitney, Spencer Michael; Kane, Heather Jean; Houtz, Robert L; Sharwood, Robert Edward

    2009-04-01

    Manipulation of Rubisco within higher plants is complicated by the different genomic locations of the large (L; rbcL) and small (S; RbcS) subunit genes. Although rbcL can be accurately modified by plastome transformation, directed genetic manipulation of the multiple nuclear-encoded RbcS genes is more challenging. Here we demonstrate the viability of linking the S and L subunits of tobacco (Nicotiana tabacum) Rubisco using a flexible 40-amino acid tether. By replacing the rbcL in tobacco plastids with an artificial gene coding for a S40L fusion peptide, we found that the fusions readily assemble into catalytic (S40L)8 and (S40L)16 oligomers that are devoid of unlinked S subunits. While there was little or no change in CO2/O2 specificity or carboxylation rate of the Rubisco oligomers, their Kms for CO2 and O2 were reduced 10% to 20% and 45%, respectively. In young maturing leaves of the plastome transformants (called ANtS40L), the S40L-Rubisco levels were approximately 20% that of wild-type controls despite turnover of the S40L-Rubisco oligomers being only slightly enhanced relative to wild type. The reduced Rubisco content in ANtS40L leaves is partly attributed to problems with folding and assembly of the S40L peptides in tobacco plastids that relegate approximately 30% to 50% of the S40L pool to the insoluble protein fraction. Leaf CO2-assimilation rates in ANtS40L at varying pCO2 corresponded with the kinetics and reduced content of the Rubisco oligomers. This fusion strategy provides a novel platform to begin simultaneously engineering Rubisco L and S subunits in tobacco plastids.

  19. 21 CFR 876.5980 - Gastrointestinal tube and accessories.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ..., gastrointestinal string and tubes to locate internal bleeding, double lumen tube for intestinal decompression or... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Gastrointestinal tube and accessories. 876.5980... (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5980 Gastrointestinal...

  20. 21 CFR 876.5980 - Gastrointestinal tube and accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., gastrointestinal string and tubes to locate internal bleeding, double lumen tube for intestinal decompression or... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Gastrointestinal tube and accessories. 876.5980... (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5980 Gastrointestinal...

  1. 21 CFR 876.5980 - Gastrointestinal tube and accessories.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ..., gastrointestinal string and tubes to locate internal bleeding, double lumen tube for intestinal decompression or... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Gastrointestinal tube and accessories. 876.5980... (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5980 Gastrointestinal...

  2. 21 CFR 876.5980 - Gastrointestinal tube and accessories.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ..., gastrointestinal string and tubes to locate internal bleeding, double lumen tube for intestinal decompression or... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Gastrointestinal tube and accessories. 876.5980... (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5980 Gastrointestinal...

  3. 21 CFR 884.4900 - Obstetric table and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Devices § 884.4900 Obstetric table and accessories. (a) Identification. An obstetric table is a device with adjustable sections designed to support a patient in the various positions required during...: patient equipment, support attachments, and cabinets for warming instruments and disposing of wastes. (b...

  4. Hunting for eruption ages in accessory minerals

    NASA Astrophysics Data System (ADS)

    Vazquez, J. A.

    2012-12-01

    A primary goal in geochronology is to provide precise and accurate ages for tephras that serve as chronostratigraphic markers for constraining the timing and rates of volcanism, sedimentation, climate change, and catastrophic events in Earth history. Zircon remains the most versatile accessory mineral for dating silicic tephras due to its common preservation in distal pyroclastic deposits, as well as the robustness of its U-Pb and U-series systems even after host materials have been hydrothermally altered or weathered. Countless studies document that zircon may be complexly zoned in age due to inheritance, contamination, recycling of antecrysts, protracted crystallization in long-lived magma reservoirs, or any combination of these. Other accessory minerals such as allanite or chevkinite can retain similar records of protracted crystallization. If the goal is to date the durations of magmatic crystallization, differentiation, and/or magma residence, then these protracted chronologies within and between accessory minerals are a blessing. However, if the goal is to date the timing of eruption with high precision, i.e., absolute ages with millennial-scale uncertainties, then this age zoning is a curse. Observations from ion microprobe 238U-230Th dating of Pleistocene zircon and allanite provide insight into the record of near-eruption crystallization in accessory minerals and serve as a guide for high-precision whole-crystal dating. Although imprecise relative to conventional techniques, ion probe analysis allows high-spatial resolution 238U-230Th dating that can document multi-millennial age distributions at the crystal scale. Analysis of unpolished rims and continuous depth profiling of zircon from small and large volume eruptions (e.g., Coso, Mono Craters, Yellowstone) reveals that the final several micrometers of crystallization often yield ages that are indistinguishable from associated eruption ages from the 40Ar/39Ar or (U-Th)/He methods. Using this approach, we

  5. Identification of verotoxin type 2 variant B subunit genes in Escherichia coli by the polymerase chain reaction and restriction fragment length polymorphism analysis.

    PubMed Central

    Tyler, S D; Johnson, W M; Lior, H; Wang, G; Rozee, K R

    1991-01-01

    A set of synthetic oligonucleotide primers was designed for use in a polymerase chain reaction protocol to specifically detect the B subunit genes in vtx2ha and vtx2hb, which code for the production of the VT2 (Shiga-like toxin II) variant cytotoxins VT2v-a and VT2v-b, respectively. An additional set of primers amplified a fragment common to the B subunits of the VT2 and the VT2 variant genes. Subsequent restriction endonuclease digestion of this amplicon permitted prediction of specific VT2 and variant genotypes on the basis of predetermined restriction fragment length polymorphisms. Genotypes of 21 VT2-producing strains of Escherichia coli were determined using this polymerase chain reaction-restriction fragment length polymorphism procedure. Four strains contained B subunit target sequences only for VT2 genes, 9 strains contained sequences only for VT2v-a genes, and 3 strains contained sequences only for VT2v-b. For genes in combination, one strain contained B subunit genes for both VT2 and VT2v-a and two strains contained B subunit genes for VT2 and VT2v-b. Two strains of E. coli O91:H21 contained both VT2v-a and VT2v-b B subunit genes. The VT2 reference strain of E. coli, E32511, was found to contain the targeted sequences from both VT2 and VT2v-a genes, whereas the recombinant E. coli, pEB1, possessed only that of the VT2 gene. The specific activities of extracellular VT2 determined in HeLa cells ranged from 0.3 to 41.7 TCD50 per microgram of protein in strains carrying the VT2 gene target and from 0 to 50.0 TCD50 per microgram of protein in strains carrying only the VT2 variant target (TCD50 is the tissue culture dose by which 50% of the cells were affected), suggesting that phenotypic expression does not correlate with genotype. Images PMID:1679436

  6. 21 CFR 884.6190 - Assisted reproductive microscopes and microscope accessories.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Assisted Reproduction... or embryos. Variations of microscopes and accessories used for these purposes would include phase...

  7. Selective Proteasomal Degradation of the B′β Subunit of Protein Phosphatase 2A by the E3 Ubiquitin Ligase Adaptor Kelch-like 15*

    PubMed Central

    Oberg, Elizabeth A.; Nifoussi, Shanna K.; Gingras, Anne-Claude; Strack, Stefan

    2012-01-01

    Protein phosphatase 2A (PP2A), a ubiquitous and pleiotropic regulator of intracellular signaling, is composed of a core dimer (AC) bound to a variable (B) regulatory subunit. PP2A is an enzyme family of dozens of heterotrimers with different subcellular locations and cellular substrates dictated by the B subunit. B′β is a brain-specific PP2A regulatory subunit that mediates dephosphorylation of Ca2+/calmodulin-dependent protein kinase II and tyrosine hydroxylase. Unbiased proteomic screens for B′β interactors identified Cullin3 (Cul3), a scaffolding component of E3 ubiquitin ligase complexes, and the previously uncharacterized Kelch-like 15 (KLHL15). KLHL15 is one of ∼40 Kelch-like proteins, many of which have been identified as adaptors for the recruitment of substrates to Cul3-based E3 ubiquitin ligases. Here, we report that KLHL15-Cul3 specifically targets B′β to promote turnover of the PP2A subunit by ubiquitylation and proteasomal degradation. Comparison of KLHL15 and B′β tissue expression profiles suggests that the E3 ligase adaptor contributes to selective expression of the PP2A/B′β holoenzyme in the brain. We mapped KLHL15 residues critical for homodimerization as well as interaction with Cul3 and B′β. Explaining PP2A subunit selectivity, the divergent N terminus of B′β was found necessary and sufficient for KLHL15-mediated degradation, with Tyr-52 having an obligatory role. Although KLHL15 can interact with the PP2A/B′β heterotrimer, it only degrades B′β, thus promoting exchange with other regulatory subunits. E3 ligase adaptor-mediated control of PP2A holoenzyme composition thereby adds another layer of regulation to cellular dephosphorylation events. PMID:23135275

  8. Role of NMDA receptor GluN2D subunit in the antidepressant effects of enantiomers of ketamine.

    PubMed

    Ide, Soichiro; Ikekubo, Yuiko; Mishina, Masayoshi; Hashimoto, Kenji; Ikeda, Kazutaka

    2017-11-01

    We investigated the rapid and sustained antidepressant effects of enantiomers of ketamine in N-methyl-d-aspartate (NMDA) receptor GluN2D subunit knockout (GluN2D-KO) mice. Intraperitoneal administration of ketamine or its enantiomers 10 min before the tail-suspension test exerted significant antidepressant effects on restraint stress-induced depression in both wildtype and GluN2D-KO mice. The antidepressant effects of (RS)-ketamine and (S)-ketamine were sustained 96 h after the injection in both wildtype and GluN2D-KO mice, but such sustained antidepressant effects of (R)-ketamine were only observed in wildtype mice. These data suggest that the GluN2D subunit is critical for the sustained antidepressant effects of (R)-ketamine. Copyright © 2017 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

  9. Classical conformal blocks and accessory parameters from isomonodromic deformations

    NASA Astrophysics Data System (ADS)

    Lencsés, Máté; Novaes, Fábio

    2018-04-01

    Classical conformal blocks appear in the large central charge limit of 2D Virasoro conformal blocks. In the AdS3 /CFT2 correspondence, they are related to classical bulk actions and used to calculate entanglement entropy and geodesic lengths. In this work, we discuss the identification of classical conformal blocks and the Painlevé VI action showing how isomonodromic deformations naturally appear in this context. We recover the accessory parameter expansion of Heun's equation from the isomonodromic τ -function. We also discuss how the c = 1 expansion of the τ -function leads to a novel approach to calculate the 4-point classical conformal block.

  10. The delta-subunit of murine guanine nucleotide exchange factor eIF-2B. Characterization of cDNAs predicts isoforms differing at the amino-terminal end.

    PubMed

    Henderson, R A; Krissansen, G W; Yong, R Y; Leung, E; Watson, J D; Dholakia, J N

    1994-12-02

    Protein synthesis in mammalian cells is regulated at the level of the guanine nucleotide exchange factor, eIF-2B, which catalyzes the exchange of eukaryotic initiation factor 2-bound GDP for GTP. We have isolated and sequenced cDNA clones encoding the delta-subunit of murine eIF-2B. The cDNA sequence encodes a polypeptide of 544 amino acids with molecular mass of 60 kDa. Antibodies against a synthetic polypeptide of 30 amino acids deduced from the cDNA sequence specifically react with the delta-subunit of mammalian eIF-2B. The cDNA-derived amino acid sequence shows significant homology with the yeast translational regulator Gcd2, supporting the hypothesis that Gcd2 may be the yeast homolog of the delta-subunit of mammalian eIF-2B. Primer extension studies and anchor polymerase chain reaction analysis were performed to determine the 5'-end of the transcript for the delta-subunit of eIF-2B. Results of these experiments demonstrate two different mRNAs for the delta-subunit of eIF-2B in murine cells. The isolation and characterization of two different full-length cDNAs also predicts the presence of two alternate forms of the delta-subunit of eIF-2B in murine cells. These differ at their amino-terminal end but have identical nucleotide sequences coding for amino acids 31-544.

  11. 21 CFR 876.4300 - Endoscopic electrosurgical unit and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Endoscopic electrosurgical unit and accessories. (a) Identification. An endoscopic electrosurgical unit and... device includes the electrosurgical generator, patient plate, electric biopsy forceps, electrode, flexible snare, electrosurgical alarm system, electrosurgical power supply unit, electrical clamp, self...

  12. Preparation and Dielectric Properties of SiC/LSR Nanocomposites for Insulation of High Voltage Direct Current Cable Accessories

    PubMed Central

    Shang, Nanqiang; Chen, Qingguo; Wei, Xinzhe

    2018-01-01

    The conductivity mismatch in the composite insulation of high voltage direct current (HVDC) cable accessories causes electric field distribution distortion and even insulation breakdown. Therefore, a liquid silicone rubber (LSR) filled with SiC nanoparticles is prepared for the insulation of cable accessories. The micro-morphology of the SiC/LSR nanocomposites is observed by scanning electron microscopy, and their trap parameters are characterized using thermal stimulated current (TSC) tests. Moreover, the dielectric properties of SiC/LSR nanocomposites with different SiC concentrations are tested. The results show that the 3 wt % SiC/LSR sample has the best nonlinear conductivity, more than one order of magnitude higher than that of pure LSR with improved temperature and nonlinear conductivity coefficients. The relative permittivity increased 0.2 and dielectric loss factor increased 0.003, while its breakdown strength decreased 5 kV/mm compared to those of pure LSR. Moreover, the TSC results indicate the introduction of SiC nanoparticles reduced the trap level and trap density. Furthermore, the SiC nanoparticles filling significantly increased the sensitivity of LSR to electric field stress and temperature changes, enhancing the conductivity and electric field distribution within the HVDC cable accessories, thus improving the reliability of the HVDC cable accessories. PMID:29518054

  13. Preparation and Dielectric Properties of SiC/LSR Nanocomposites for Insulation of High Voltage Direct Current Cable Accessories.

    PubMed

    Shang, Nanqiang; Chen, Qingguo; Wei, Xinzhe

    2018-03-08

    The conductivity mismatch in the composite insulation of high voltage direct current (HVDC) cable accessories causes electric field distribution distortion and even insulation breakdown. Therefore, a liquid silicone rubber (LSR) filled with SiC nanoparticles is prepared for the insulation of cable accessories. The micro-morphology of the SiC/LSR nanocomposites is observed by scanning electron microscopy, and their trap parameters are characterized using thermal stimulated current (TSC) tests. Moreover, the dielectric properties of SiC/LSR nanocomposites with different SiC concentrations are tested. The results show that the 3 wt % SiC/LSR sample has the best nonlinear conductivity, more than one order of magnitude higher than that of pure LSR with improved temperature and nonlinear conductivity coefficients. The relative permittivity increased 0.2 and dielectric loss factor increased 0.003, while its breakdown strength decreased 5 kV/mm compared to those of pure LSR. Moreover, the TSC results indicate the introduction of SiC nanoparticles reduced the trap level and trap density. Furthermore, the SiC nanoparticles filling significantly increased the sensitivity of LSR to electric field stress and temperature changes, enhancing the conductivity and electric field distribution within the HVDC cable accessories, thus improving the reliability of the HVDC cable accessories.

  14. Study on development of accessory sex glands in prepubertal kids using two-dimensional ultrasonography

    PubMed Central

    Kumari, Sonu; Luthra, R. A.; Chandolia, R. K.; Kumar, Sandeep; Kumar, Parveen; Devender; Kumar, Ankit; Bishnoi, Nidhi; Bishnoi, Sunil

    2016-01-01

    Aim: The present study was undertaken to study growth pattern of accessory sex glands in prepubertal kids from 2 weeks to 6 months of age using two-dimensional ultrasonography. Materials and Methods: The study was conducted on six Beetal kids. The scanning of accessory sex glands was done in standing position using rectal probe and measurements were recorded. Data collected were statistically analyzed using one-way ANOVA followed by Duncan multiple range test was performed using the SPSS (16.0) system for windows. Results: With the advancement of age all the dimensions of glands increased. Both the lobes of prostate gland showed an increase in width with advancement of age. Width of prostate above the urethra (W1) showed a significant increase at 2, 10, and 20 weeks of age, whereas non-significant increase from 2 to 8, 10 to 19, and 20 to 24 weeks of age was recorded. Width of prostate below the urethra (W2) showed a significant increase at 20 weeks of age, whereas non-significant increase was recorded during rest of period of growth. Left and right bulbourethral gland showed a similar pattern of growth with the advancement of age. The circumference dimensions increased significantly at 2, 16, 20, and 21 weeks of age for both glands. The increase was non-significant from 4 to 14, 16 to 19, and 20 to 23 weeks of age. The same pattern was observed for left and right seminal vesicular gland. Conclusion: Significant growth in three accessory sex glands in prepubertal kids was not observed at the same age. The trend observed was that the prostate was the first gland to show significant growth at 10 weeks of age followed by a significant increase in seminal vesicles and bulbourethral gland at 14 and 16 weeks of age, respectively. PMID:27182127

  15. Study on development of accessory sex glands in prepubertal kids using two-dimensional ultrasonography.

    PubMed

    Kumari, Sonu; Luthra, R A; Chandolia, R K; Kumar, Sandeep; Kumar, Parveen; Devender; Kumar, Ankit; Bishnoi, Nidhi; Bishnoi, Sunil

    2016-04-01

    The present study was undertaken to study growth pattern of accessory sex glands in prepubertal kids from 2 weeks to 6 months of age using two-dimensional ultrasonography. The study was conducted on six Beetal kids. The scanning of accessory sex glands was done in standing position using rectal probe and measurements were recorded. Data collected were statistically analyzed using one-way ANOVA followed by Duncan multiple range test was performed using the SPSS (16.0) system for windows. With the advancement of age all the dimensions of glands increased. Both the lobes of prostate gland showed an increase in width with advancement of age. Width of prostate above the urethra (W1) showed a significant increase at 2, 10, and 20 weeks of age, whereas non-significant increase from 2 to 8, 10 to 19, and 20 to 24 weeks of age was recorded. Width of prostate below the urethra (W2) showed a significant increase at 20 weeks of age, whereas non-significant increase was recorded during rest of period of growth. Left and right bulbourethral gland showed a similar pattern of growth with the advancement of age. The circumference dimensions increased significantly at 2, 16, 20, and 21 weeks of age for both glands. The increase was non-significant from 4 to 14, 16 to 19, and 20 to 23 weeks of age. The same pattern was observed for left and right seminal vesicular gland. Significant growth in three accessory sex glands in prepubertal kids was not observed at the same age. The trend observed was that the prostate was the first gland to show significant growth at 10 weeks of age followed by a significant increase in seminal vesicles and bulbourethral gland at 14 and 16 weeks of age, respectively.

  16. 21 CFR 884.4100 - Endoscopic electrocautery and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Endoscopic electrocautery and accessories. 884.4100 Section 884.4100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... ammeters: continue electrode activation for 5 seconds after the visual endpoint (tissue blanching) is...

  17. 21 CFR 890.3025 - Prosthetic and orthotic accessory.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Prosthetic and orthotic accessory. 890.3025 Section 890.3025 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3025...

  18. 21 CFR 890.3025 - Prosthetic and orthotic accessory.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Prosthetic and orthotic accessory. 890.3025 Section 890.3025 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3025...

  19. 21 CFR 890.3025 - Prosthetic and orthotic accessory.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Prosthetic and orthotic accessory. 890.3025 Section 890.3025 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3025...

  20. 21 CFR 890.3025 - Prosthetic and orthotic accessory.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Prosthetic and orthotic accessory. 890.3025 Section 890.3025 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3025...