In this study we report that the protein kinase CK2 phosphorylates survivin specifically on threonine 48 (T48) within its BIR domain, and that T48 is critical to both the mitotic and anti-apoptotic roles of survivin. Interestingly, during mitosis T48 mutants localise normally, but are unable to support cell growth when endogenous survivin is removed by siRNA. In addition, while overexpression of ...

Apoptosis is a tightly controlled process regulated by many signaling pathways; however, the mechanisms and cellular events that decide whether a cell lives or dies remain poorly understood. Here we showed that when a cell is under apoptotic stress, the prosurvival protein Survivin redistributes from the cytoplasm to the nucleus, thus acting as a ...

Proneurotrophins mediate neuronal apoptosis using a dual receptor complex of sortilin and p75^NTR. Although p75^NTR is highly expressed on the plasma membrane and accessible to proneurotrophin ligands, sortilin is primarily localized to intracellular membranes, limiting the formation of a cell surface co-receptor complex. Here, we show that the mammalian ...

Acutely transforming retrovirus AKT8 in rodent T cell lymphoma (Akt) phosphorylates and regulates the function of many cellular proteins involved in processes such as metabolism, apoptosis and proliferation. However, the precise mechanisms by which Akt promotes cell survival and inhibits apoptosis have been characterized in part only. TR3, an orphan receptor, functions as a transcription factor ...

Deletion of a small cytoplasmic fragment close to the fourth transmembrane segment of the nicotinic ?7 receptor (Glu437 to Arg447) abolished membrane expression. Different single mutants showed moderate to strong decreases in expression whereas the latter was totally abolished upon proline substitutions. We hypothesize that ...

Irrespective of their effects on ongoing host protein synthesis, productive replication of the representative alphaherpesvirus herpes simplex virus type 1, the representative gammaherpesvirus Kaposi's sarcoma herpesvirus, and the representative betaherpesvirus human cytomegalovirus [HCMV] stimulates the assembly of the multisubunit, cap-binding translation factor eIF4F. However, only HCMV ...

BackgroundInterferon regulatory factor 2 binding protein 2 (IRF2BP2) is a muscle-enriched transcription factor required to activate vascular endothelial growth factor-A (VEGFA) expression in muscle. IRF2BP2 is found in the nucleus of cardiac and skeletal muscle cells. During the process of skeletal muscle differentiation, some IRF2BP2 becomes relocated to the cytoplasm, ...

). The GDC displays nomifensine-sensitive DA uptake, reserpine- sensitive vesicular DA uptake. Peak 2 appears later and is broader; fur- thermore, it is abolished by prior reserpine treatment an action of AMPH at the vesicular level. A number of reports on the effects of reserpine on AMPH

Activation of caspase-1 is essential for the maturation and release of interleukin (IL)-1? and IL-18, and occurs in multi-protein complexes, referred to as inflammasomes. The apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) is the essential adaptor protein for recruiting pro-caspase-1 into inflammasomes, and consistently gene ablation of ASC ...

Herpes simplex virus (HSV) glycoprotein B (gB) is one of the four viral glycoproteins required for viral entry and cell fusion and is highly conserved among herpesviruses. Mutants of HSV type 2 gB were generated by substituting conserved residues in the cytoplasmic tail with alanine or by deleting 41 amino acids from the C-terminus. Some of the mutations ...

Both myeloperoxidase (MPO) and elastase were found to be redistributed in ethanol-and Bouin-fixed human neutrophil granulocytes. Air-dried and formalin-fixed cells, stained for MPO, appeared with a cytoplasmic fluorescence and unstained nuclei. In elastase air-dried cells a faint perinuclear staining was also detected. Otherwise the ...

Compound C is commonly used as an inhibitor of AMP-activated protein kinase (AMPK), which serves as a key energy sensor in cells. In this study, we found that Compound C treatment of MCF7 cells led to Bax redistribution from the cytoplasm to mitochondria and cell death. However, this effect does not involve AMPK. In addition, we found that treatment with ...

[beta]-Furfuryl-[beta]-glucoside (FG) has been shown to be a specific endogenous activator of higher plant callose synthase. Because glycosides such as FG are usually sequestered in vacuoles, we have proposed that activation of callose synthesis in vivo may involve a change in the compartmentation on FG and Ca[sup 2+], resulting in a synergistic activation of callose synthase. The use of ...

BackgroundThe alkylating agent Dacarbazine (DTIC) has been used in the treatment of melanoma for decades, but when used as a monotherapy for cancer only moderate response rates are achieved. Recently, the clinical use of Temozolomide (TMZ) has become the more commonly used analog of DTIC-related oral agents because of its greater bioavailability and ability to cross the blood brain barrier. The ...

Defined branched peptides (loligomers) incorporating cytoplasmic translocation signals, nuclear localization sequences, and fluorescent probes were designed and synthesized to demonstrate the feasibility and simplicity of creating novel classes of intracellular vehicles. Loligomers containing all the above signals were rapidly internalized by Chinese hamster ovary (CHO) cells ...

Allosteric regulation of several sugar transport systems such as those specific for lactose, maltose and melibiose in Escherichia coli (inducer exclusion) is mediated by the glucose-specific enzyme IIA (IIAGlc) of the phosphoenolpyruvate:sugar phosphotransferase system (PTS). Deletion mutations in the cytoplasmic N and C termini of the lactose permease protein, LacY, and ...

Veratridine produced a dose-dependent release of cytoplasmic [3H]dopamine in rat corpus striatal slices. Cytoplasmic [3H]dopamine was obtained by pretreating rats with reserpine to inhibit vesicular storage and incubating with pargyline and beta-thujaplicin to inhibit catabolism prior to incubation with [3H]dopamine. Release of [3H]dopamine by veratridine ...

Approximately 50% of familial Alzheimer's disease (AD) cases are linked to the presenilin (PS) gene. This suggests that an altered function of mutated PSs accounts for a fundamental process leading to AD. Here we identify a new PS binding protein, PBP, which is highly expressed in cerebral cortex and hippocampus. immunohistochemical studies and cell fractionation analysis show that PBP ...

The activity of the electrolyte transport enzyme, sodium, potassium-activated adenosine triphosphatase (Na+,K+-ATPase), in the gills of the pinfish, Lagodon rhomboides, increased markedly following transfer of fish from brackish water to seawater. Cytochemical localization of Na+,K+-ATPase via its potassium-dependent phosphatase (K+-NPPase) activity in the branchial epithelium of pinfish adapted ...

The effects of parathyroid hormone on the cytoplasmic Ca2+ concentration of canine renal proximal tubule cells grown in primary culture were determined using the fluorescent Ca2+ indicator quin 2. The cultured cells exhibited responses to hormones, enzyme activities, transport functions, and morphology characteristic of the proximal convoluted tubule. Parathyroid hormone ...

The effects of parathyroid hormone on the cytoplasmic CaS concentration of canine renal proximal tubule cells grown in primary culture were determined using the fluorescent CaS indicator quin 2. The cultured cells exhibited responses to hormones, enzyme activities, transport functions, and morphology characteristic of the proximal convoluted tubule. Parathyroid hormone ...

Extensive morphological modification occurs during mammalian spermiogenesis when spermatids change their spherical shape into cells with a compact head and a long tail. In this study, freeze-fracture was used to elucidate the alteration of the nuclear envelope during this process. Nuclear condensation resulted in a great reduction of spermatid nuclear volume and the formation of the redundant ...

Polyglutamine expansion in the N terminus of huntingtin (htt) causes selective neuronal dysfunction and cell death by unknown mechanisms. Truncated htt expressed in vitro produced htt immunoreactive cytoplasmic bodies (htt bodies). The fibrillar core of the mutant htt body resisted protease treatment and contained cathepsin D, ubiquitin, and heat shock protein (HSP) 40. The ...

Chloroplasts are actively anchored at the appropriate intracellular regions to maintain advantageous distribution patterns under specific environmental conditions. Redistribution of chloroplasts is accompanied with their de-anchoring and re-anchoring, respectively, from and to the cortical cytoplasm. In spinach mesophyll cells, high-intensity blue light ...

Sodium-dependent transporters are inhibited indirectly by the Na-K-ATPase inhibitor ouabain. Here we report stimulation of sodium-hydrogen exchange (NHE) in ouabain-treated cells. BCECF was used to measure cytoplasmic pH in cultured rat optic nerve astrocytes. Ammonium chloride was applied to acid load the cells. On removal of ammonium chloride, ...

Herpes simplex virus (HSV) and other alphaherpesviruses assemble enveloped virions in the trans-Golgi network (TGN) or endosomes. Enveloped particles are formed when capsids bud into TGN/endosomes and virus particles are subsequently ferried to the plasma membrane in TGN-derived vesicles. Little is known about the last stages of virus egress from the TGN/endosomes to cell surfaces except that the ...

The regulation of cytoplasmic Ca²⁺ is crucial for various cellular processes. Here, we examined the cytoplasmic Ca²⁺ levels in living fission yeast cells by a highly sensitive bioluminescence resonance energy transfer-based assay using GFP-aequorin fusion protein linked by 19 amino acid. We monitored the ...

BackgroundLymph nodes constitute the first site of metastasis for most malignancies, and the extent of lymph node involvement is a major criterion for evaluating patient prognosis. The CXC chemokine receptor 4 (CXCR4) has been shown to play an important role in lymph node metastasis. Nitric oxide (NO) may also contribute to induction of metastatic ability in human cancers.MethodsCXCR4 expression ...

Inclusion body myopathy associated with Paget�s disease of bone and frontotemporal dementia (IBMPFD) is a dominantly inherited degenerative disorder caused by mutations in the valosin-containing protein (VCP) gene. VCP (p97 in mouse, TER94 in D. melanogaster, and CDC48 in S. cerevisiae) is a highly conserved AAA⁺-ATPase that regulates a wide array of cellular processes. ...

We have examined the subcellular distribution of alpha s, the alpha subunit of the heterotrimeric G protein Gs, by using immunofluorescence microscopy. In transiently transfected HEK293 cells, wild-type alpha s localizes to the plasma membrane. However, a mutationally activated alpha s (alpha sR201C) is diffusely distributed throughout the cytoplasm. Similarly, cholera toxin ...

A method is described for the quantitative determination of free and bound solute concentrations in the cytoplasm of intact cells. The method includes (a) introduction of a gelatin gel reference phase (RP) into the cytoplasm; (b) diffusion of dissolved substances between cytoplasm and RP, (c) cell quenching to - 196 degrees C to ...

CXCR4 regulates cell proliferation, enhances cell survival and induces chemotaxis, yet molecular mechanisms underlying its signaling remain elusive. Like all other G-protein coupled receptors (GPCRs), CXCR4 delivers signals through G-protein-dependent and -independent pathways, the latter involving its serine-rich cytoplasmic tail. To evaluate the signaling and biological ...

Glyceraldehyde-3-phosphate dehydrogenase (G3PDH, EC 1.2.1.12) release from haemolysing erythrocytes, and its redistribution between free and membrane-bound states, were studied with a new type of rapid-mixing filtration apparatus. The apparatus is described. The results indicate that the rate of G3PDH appearance in filtrates is determined not only by the enzyme ...

Alpha actinin (ACTN) has emerged as a multitasking protein, whose roles range from bundling actin filaments to functioning as a versatile protein interaction platform for proteins involved in structural or signaling aspects. We report here that ACTN2, one of the four ACTN isoforms, may shuttle between the cytoplasm and nucleus where the nuclear exportation takes place in a ...

Chronic oxidative stress results in decreased responsiveness to insulin, eventually leading to diabetes and cardiovascular disease. Activation of the JNK signaling pathway can mediate many of the effects of stress on insulin resistance through inhibitory phosphorylation of insulin receptor substrate 1. By contrast, exercise, which acutely increases oxidative stress in the muscle, improves insulin ...

In eukaryotic cells, the nuclear envelope partitions the nucleus from the cytoplasm. The fission yeast Schizosaccharomyces pombe undergoes closed mitosis in which the nuclear envelope persists rather than being broken down, as in higher eukaryotic cells. It is therefore assumed that nucleocytoplasmic transport continues during the cell cycle. Here we show that nuclear ...

Mechanosensitive channels are a class of ubiquitous membrane proteins gated by mechanical strain in the cellular membrane. MscS, the mechanosensitive channel of small conductance, is found in the inner membrane of Escherichia coli and its crystallographic structure in an open form has been recently solved. By means of molecular dynamics simulations we studied the stability of the channel ...

Male gametogenesis occurs directly after uptake of malaria parasites by the mosquito vector and leads to the release of eight nucleated flagellar gametes. Here, we report that one of the two parasite actin isoforms, named actin II, is essential for this process. Disruption of actin II in Plasmodium berghei resulted in viable asexual blood stages, but male gametogenesis was specifically inhibited. ...

GnRH is released from hypothalamic neurons in coordinated pulses, but the cellular basis for this process is poorly understood. Previously, we found that secretory pulses from GT1-7 cells became synchronized with time in culture. Using this culture model, we investigated whether the gap junction proteins connexin43 (Cx43) and/or connexin26 (Cx26) are involved in this synchronization. Our results ...

We have followed the redistribution of Golgi stacks during mitosis and cytokinesis in living tobacco BY-2 suspension culture cells by means of a green fluorescent protein-tagged soybean ?-1,2 mannosidase, and correlated the findings to cytoskeletal rearrangements and to the redistribution of endoplasmic reticulum, mitochondria, and plastids. In preparation ...

The tumour suppressor EWI2 associates with tetraspanins and regulates tumour cell movement and proliferation. The short cytoplasmic domain of EWI2 is positively charged; five out of the ten residues of this domain are basic. In the present study we demonstrated that the EWI2 cytoplasmic tail interacts specifically with negatively charged PIPs ...

The authors analysed the capacity of various temperature fractions of RNA isolated from the spleen of donors of the bone marrow cells (of mice C57BL/6I) and recipients--hybrids (CBA X C57BL/6I) F1 to abolish the depression of colony formation in the nonsyngenous organism. In the administration of bone marrow cells of mice of parental genotype C57BL/6I of the irradiated ...

Chloroplast redistribution in the cell depends on direction, fluence-rate and spectral composition of the incident light. Two photoreceptors, phototropin 1 and 2, control the chloroplast responses in higher land plants. Actin and myosin form the motor system. Although numerous results point to calcium and phosphoinositides as the secondary messengers, the signal transduction ...

Filaments 5 nm thick, located throughout the cytoplasm mainly along the surface, are observed in intact lymphocytes. In the control glycerinized lymphocytes, besides the above filaments aggregations of filaments nearly 3 nm in diameter were found. After the treatment of cells by antimurine serum or ferritin-conjugated concanavalin A, some fibrillar structures are observed ...

Administration of estrogens is known to lower the concentration of cholesterol esters in the blood vessel wall and may delay the development of arteriosclerosis. It is also known that under the influence of estrogens the redistribution of concentrations of free cholesterol and cholesterol esters takes place in rats between the blood and liver as a result of the intensification ...

Astroviruses are known to be a leading cause of diarrhea in infants and the immunocompromised; however, our understanding of this endemic pathogen is limited. Histological analyses of astrovirus pathogenesis demonstrate clinical disease is not associated with changes to intestinal architecture, inflammation, or cell death. Recent studies in vitro have suggested astroviruses induce actin ...

Cytosolic free Ca2+ and actin microfilaments play crucial roles in regulation of pollen germination and tube growth. The focus of this study is to test the hypothesis that Ca2+ channels, as well as channel-mediated Ca2+ influxes across the plasma membrane (PM) of pollen and pollen tubes, are regulated by actin microfilaments and that cytoplasmic Ca2+ in pollen and pollen tubes ...

Cytosolic free Ca²⁺ and actin microfilaments play crucial roles in regulation of pollen germination and tube growth. The focus of this study is to test the hypothesis that Ca²⁺ channels, as well as channel-mediated Ca²⁺ influxes across the plasma membrane (PM) of pollen and pollen tubes, are regulated by actin microfilaments and ...

The low-density lipoprotein (LDL) receptor-related protein (LRP) is a multiligand endocytic receptor that belongs to the LDL receptor family. Recently, studies have revealed new roles of LDL receptor family members as transducers of extracellular signals. Our previous studies have demonstrated LRP phosphorylation within its cytoplasmic tail, but the nature of LRP ...

The low-density lipoprotein (LDL) receptor-related protein (LRP) is a multiligand endocytic receptor that belongs to the LDL receptor family. Recently, studies have revealed new roles of LDL receptor family members as transducers of extracellular signals. Our previous studies have demonstrated LRP phosphorylation within its cytoplasmic tail, but the nature of LRP ...

Integrin cytoplasmic tails contain motifs that link extracelluar information to cell behavior such as cell migration and contraction. To investigate the cell functions mediated by the conserved motifs, we created mutations in the Caenorhabditis elegans ?pat-3 cytoplasmic tail. The ?1D (⁷⁹⁹FK⁸⁰⁰), NPXY, ...

In wild-type strains of Escherichia coli, alkaline phosphatase (AP), either when present as a soluble protein or when fused to a membrane protein, is only active after translocation to the periplasm. In thioredoxin reductase (trxB) mutants, however, cytoplasmically localized AP can form disulphide bonds and can reach an active conformation. Once it has folded in the ...

Rat 6 fibroblast cell lines expressing wild-type chicken liver glycoprotein receptor (CHL) or chimeric receptors with alternate cytoplasmic tails were produced to study the role of the cytoplasmic tail in mediating receptor localization in coated pits and endocytosis of ligand. Cells expressing CHL or cells expressing a hybrid receptor that contains the ...

Helicobacter pylori colonizes the normal human stomach by maintaining both periplasmic and cytoplasmic pH close to neutral in the presence of gastric acidity. Urease activity, urea flux through the pH-gated urea channel, UreI, and periplasmic alpha-carbonic anhydrase are essential for colonization. Exposure to pH 4.5 for up to 180 min activates total bacterial urease ...

MUC1, a transmembrane glycoprotein, is abnormally over-expressed in most human adenocarcinomas. MUC1 association with cytoplasmic cell signal regulators and nuclear accumulation are important for its tumor related activities. Little is known about how MUC1 translocates from the cell membrane to the cytoplasm. In this study, live cell imaging was used to ...

The oocytes of most mammalian species, including mouse and human, are fertilized in metaphase of the second meiotic division. A fertilizing spermatozoon introduces an oocyte-activating factor, phospholipase C zeta, triggering oscillations of the cytoplasmic concentration of free calcium ions ([Ca(2+)](i)) in the oocyte. [Ca(2+)](i) oscillations are essential for the activation ...

The RNA binding protein CPEB (cytoplasmic polyadenylation element binding) regulates cytoplasmic polyadenylation and translation in germ cells and the brain. In neurons, CPEB is detected at postsynaptic sites, as well as in the cell body. The related CPEB3 protein also regulates translation in neurons, albeit probably not through polyadenylation; it, as ...

TAR DNA binding protein of 43 kDa (TDP-43) is a nuclear factor functioning in RNA processing. It is also a major deposited protein in amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration with ubiquitin (FTLD-U). To understand the mechanism underlying the inclusion body formation and possible functional alteration, we studied some TDP-43 fragments and their effects on RNA ...

Mutations in fused in sarcoma (FUS) are a cause of familial amyotrophic lateral sclerosis (fALS). Patients carrying point mutations in the C-terminus of FUS show neuronal cytoplasmic FUS-positive inclusions, whereas in healthy controls, FUS is predominantly nuclear. Cytoplasmic FUS inclusions have also been identified in a subset of frontotemporal lobar ...

Previous work from our laboratory suggested that microtubules are released from the neuronal centrosome and then transported into the axon (Ahmad, F.J., and P.W. Baas. 1995. J. Cell Sci. 108: 2761�2769). In these studies, cultured sympathetic neurons were treated with nocodazole to depolymerize most of their microtubule polymer, rinsed free of the drug for a few minutes to permit a burst of ...

During formation of HIV particles, the Gag polyproteins are thought to interact with Vpr proteins to promote their encapsidation in the nascent particles. To directly visualize and monitor the formation of the Gag-Vpr complexes and correlate their formation with Vpr oligomerization, we used two photon lifetime imaging microscopy (FLIM) and time laps microscopy on HeLa cells expressing ...