Osteoclasts are specialized cells that secrete lysosomal acid hydrolases at the site of bone resorption, a process critical for skeletal formation and remodeling. However, the cellular mechanism underlying this secretion and the organization of the endo-lysosomal system of osteoclasts have remained unclear. We report that osteoclasts differentiated in ...
PubMed
Most newly synthesized soluble lysosomal proteins are delivered to the lysosome via the mannose 6-phosphate (Man-6-P)-targeting pathway. The presence of the Man-6-P post-translational modification allows these proteins to be affinity-purified on immobilized Man-6-P receptors. This approach has formed the basis for a number of proteomic ...
We previously classified photosensitizing agents based on sites of photodamage: mitochondria, lysosomes and the plasma membrane. More recent studies have indicated that the first target for the mitochondrial sensitizers is the anti-apoptotic protein bcl-2. Loss of bcl-2 results in a high bax/bcl-2 ratio, leading to an apoptotic response involving ...
NASA Astrophysics Data System (ADS)
Continuous renewal of intracellular components is required to preserve cellular functionality. In fact, failure to timely turnover proteins and organelles leads often to cell death and disease. Different pathways contribute to the degradation of intracellular components in lysosomes or autophagy. In this review, we focus on chaperone-mediated autophagy (CMA), a ...
PubMed Central
Autophagy is primarily a non-selective intracellular bulk degradation process. However, it was recently shown that ubiquitin-positive substrates, such as protein aggregates, mitochondria, peroxisomes, and invading bacteria, are selectively targeted to lysosomes via autophagy. Thus, ubiquitination seems to function ...
The extensive autophagic-lysosomal pathology in Alzheimer disease (AD) brain has revealed a major defect: in the proteolytic clearance of autophagy substrates. Autophagy failure contributes on several levels to AD pathogenesis and has become an important therapeutic target for AD and other neurodegenerative diseases. We recently observed broad therapeutic ...
Macroautophagy and chaperone-mediated autophagy (CMA) are the two main mammalian lysosomal proteolytic systems. In macroautophagy, double-membrane structures engulf organelles and other intracellular constituents through a highly regulated process that involves the formation of autophagic vacuoles and their fusion with lysosomes. In CMA, ...
At short intervals after the intravenous administration of oestradiol-17?, diethylstilboestrol, testosterone or saline control solution to ovariectomized rats, highly purified lysosome samples were prepared in substantial yield from preputial glands, sex accessory organs rich in these organelles. The preparations were essentially devoid of mitochondrial contamination. Exposure ...
Chaperone-mediated autophagy (CMA) is a selective lysosomal pathway for the degradation of cytosolic proteins. We review in this work some of the recent findings on this pathway regarding the molecular mechanisms that contribute to substrate targeting, binding and translocation across the lysosomal membrane. We ...
The metal chelating compound Dp44mT is a di-2-pyridylketone thiosemicarbazone (DpT) which displays potent and selective anti-tumor activity. This compound is receiving translational attention but its mechanism is poorly understood. Here we report that Dp44mT targets lysosome integrity through copper binding. Studies using the ...
Autophagy is a conserved cellular process to degrade and recycle cytoplasmic components. During autophagy, lysosomes fuse with an autophagosome to form an autolysosome. Sequestered components are degraded by lysosomal hydrolases and presumably released into the cytosol by lysosomal efflux permeases. Following starvation-induced ...
Multiple pathways of protein degradation operate within cells. A selective protein import pathway exists for the uptake and degradation of particular cytosolic proteins by lysosomes. Here, the lysosomal membrane glycoprotein LGP96 was identified as a receptor for the selective import and degradation of proteins ...
pH varies widely among the different intracellular compartments. The establishment and maintenance of a particular pH appears to be critical for proper organellar function. This has been deduced from experiments where intraorganellar pH was altered by means of weak acids or bases, ionophores or inhibitors of the vacuolar H(+) -ATPase (V-ATPase). These manipulations, however, are not specific and ...
Niemann-Pick type C (NPC) disease is a lysosomal storage disorder characterized at the cellular level by abnormal accumulation of cholesterol and other lipids in lysosomal storage organelles. Lysosomal acid lipase (LAL) has been recently identified as a potential therapeutic target for NPC. LAL can be specifically ...
Lysosomal destabilization is critical for the organelle and living cells. Using methyl-beta-cyclodextrin (M beta CD) to selectively deplete lysosomal membrane cholesterol, we investigated the effect of cholesterol on the organelle osmotic stability. The results show that loss of membrane cholesterol caused changes in the ...
IL-4-induced gene-1 (Il4i1 or Fig1) initially isolated as a gene of unknown function from mouse B lymphocytes, is limited in expression to primarily immune tissues and genetically maps to a region of susceptibility to autoimmune disease. The predicted Il4i1 protein (IL4I1) sequence is most similar to apoptosis-inducing protein and Apoxin I, both l-amino acid oxidases (LAAO; Enzyme Commission ...
Recently, using 2D-DIGE proteomics we have identified cathepsin B as a novel target of UVA in human Hs27 skin fibroblasts. In response to chronic exposure to noncytotoxic doses of UVA (9.9 J cm(-2), twice a week, 3 weeks), photooxidative impairment of cathepsin B enzymatic activity occurred with accumulation of autofluorescent aggregates colocalizing with ...
Syt VII is a Ca(2+) sensor that regulates lysosome exocytosis and plasma membrane repair. Because it lacks motifs that mediate lysosomal targeting, it is unclear how Syt VII traffics to these organelles. In this paper, we show that mutations or inhibitors that abolish palmitoylation disrupt Syt VII targeting to ...
Syt VII is a Ca2+ sensor that regulates lysosome exocytosis and plasma membrane repair. Because it lacks motifs that mediate lysosomal targeting, it is unclear how Syt VII traffics to these organelles. In this paper, we show that mutations or inhibitors that abolish palmitoylation disrupt Syt VII ...
Target cell Golgi EE Lysosome Exosome Cytosol Fig1 | Protein transport in the endo-lysosomal pathways).Pathways linking the MVB with other compartments,such as the early endosome (EE),Golgi,lysosome and plasma membrane even evolved mechanisms to avoid degradation by inhibiting the trans- port of MVBs to ...
E-print Network
The mammalian target of rapamycin (mTOR) is a well-conserved negative regulator of autophagy. Here we review our recent data describing how lysosomal positioning influences and coordinates mTOR activity, autophagosome biogenesis and autophagosome-lysosome fusion. In this way, lysosomal positioning regulates many ...
Papain family cysteine proteases are key factors in the pathogenesis of cancer invasion, arthritis, osteoporosis, and microbial infections. Targeting this enzyme family is therefore one strategy in the development of new chemotherapy for a number of diseases. Little is known, however, about the efficacy, selectivity, and safety of cysteine protease ...
BackgroundNiemann-Pick type C (NPC) disease is a genetically inherited multi-lipid storage disorder with impaired efflux of cholesterol from lysosomal storage organelles.Methodology/Principal FindingsThe effect of screen-selected cholesterol lowering compounds on the major sterol pathways was studied in CT60 mutant CHO cells lacking NPC1 protein. Each of ...
The lysosomal cysteine protease cathepsin K is a target for osteoporosis therapy. The aryl-piperazine-containing cathepsin K inhibitor CRA-013783/L-006235 (1) displays greater than 4000-fold selectivity against the lysosomal/endosomal antitargets cathepsin B, L, and S. However, 1 and other ...
After de novo synthesis of lysosome-associated membrane proteins (LAMPs), they are sorted in the trans-Golgi network (TGN) for delivery to lysosomes. Opposing views prevail on whether LAMPs are targeted to lysosomes directly, or indirectly via prelysosomal stages of the endocytic pathway, in particular early ...
Many human diseases result from mutations in specific genes. Once translated, the resulting aberrant proteins may be functionally competent and produced at near-normal levels. However, because of the mutations, the proteins are recognized by the quality control system of the endoplasmic reticulum and are not processed or trafficked correctly, ultimately leading to cellular dysfunction and disease. ...
AbstractMany human diseases result from mutations in specific genes. Once translated, the resulting aberrant proteins may be functionally competent and produced at near-normal levels. However, because of the mutations, the proteins are recognized by the quality control system of the endoplasmic reticulum and are not processed or trafficked correctly, ultimately leading to cellular dysfunction and ...
The function of lysosomes relies on the ability of the lysosomal membrane to fuse with several target membranes in the cell. It is known that in lysosomal storage disorders (LSDs), lysosomal accumulation of several types of substrates is associated with lysosomal ...
We sought to develop a sensitive and quantitative technique capable of monitoring the entire flux of autophagy involving fusion of lysosomal membranes. We observed the accumulation inside lysosomal compartments of Keima, a coral-derived acid-stable fluorescent protein that emits different-colored signals at acidic and neutral pHs. The cumulative ...
While lysosomal disruption seems to be a late step of necrosis, a moderate lysosomal destabilization has been suggested to participate early in the apoptotic cascade. The origin of lysosomal dysfunction and its precise role in apoptosis or apoptosis-like process still needs to be clarified, especially upon carcinogen exposure. In this ...
Energy Citations Database
Activated human T lymphocytes exposed to apoptotic stimuli targeting mitochondria (i.e. staurosporine), enter an early, caspase-independent phase of commitment to apoptosis characterized by cell shrinkage and peripheral chromatin condensation. We show that during this phase, AIF is selectively released from the intermembrane space of mitochondria, and that ...
Bicistronic cassettes under control of a single promoter have recently been suggested as useful tools for coordinate expression of two different foreign proteins in mammalian cells. Using the long 5' untranslated region of encephalomyocarditis virus as translational enhancer of the second gene, a bicistronic unit composed of cDNA for human P-glycoprotein [the product of the multidrug resistance ...
A long-term goal of cancer diagnosis is to develop tumor-imaging techniques that have sufficient specificity and sensitivity. To achieve this goal, minimizing the background signal originating from nontarget tissues is crucial. Here we achieve highly specific in vivo cancer visualization by using a newly designed targeted 'activatable' fluorescent imaging probe. This agent is ...
Photodynamic therapy (PDT) with lysosome-targeted photosensitizers induces the intrinsic pathway of apoptosis via the cleavage and activation of the BH3-only protein Bid by proteolytic enzymes released from photo-disrupted lysosomes. To investigate the role of Bid in apoptosis induction and the role of damaged lysosomes on cell killing ...
Modern drug delivery system demands high therapeutic efficacy and low toxicity which depends on efficient intracellular transportation of therapeutics to specific organisms, cells, even targeted organelles such as cytosol, nucleus, mitochondria, lysosome and endoplasmic reticulum. Intracellular barriers which prevent drug molecules accessing to their ...
We have observed that Au nanorods (NRs) have distinct effects on cell viability via killing cancer cells while posing negligible impact on normal cells and mesenchymal stem cells. Obvious differences in cellular uptake, intracellular trafficking, and susceptibility of lysosome to Au NRs by different types of cells resulted in selective accumulation of Au ...
The use of lysosome-targeted liposomes may significantly improve the delivery of therapeutic enzymes and chaperones into lysosomes for the treatment of lysosomal storage disorders. The aim of this research was to synthesize new potentially lysosomotropic ligands on a base of Neutral Red and rhodamine B and to study their ability to ...
The subcellular localization of lanthane was studied using two microanalytic methods. 1.) The election microprobe method showed that lanthane is concentrated in the lysosomes of the hepatocytes and the spleen associated with phosphorus. 2.) The ion microanalysis showed that lanthane is selectively precipitated in the lysosomes of the ...
New BODIPY-based pH probes have been designed with excitation and emission wavelengths suitable for fluorescence microscopy and flow cytometry. These pH probes are cell-permeable, selectively label lysosomes, and can be used for noninvasive monitoring of lysosomal pH changes during physiological and pathological processes. ...
Incomplete lysosomal acidification in microglia inhibits the degradation of fibrillar forms of Alzheimer's amyloid ? peptide (fA?). Here we show that in primary microglia a chloride transporter, ClC-7, is not delivered efficiently to lysosomes, causing incomplete lysosomal acidification. ClC-7 protein is synthesized by microglia but it ...
Alzheimer's disease (AD) is an age-related neurodegenerative pathology in which defects in proteolytic clearance of amyloid ? peptide (A?) likely contribute to the progressive nature of the disorder. Lysosomal proteases of the cathepsin family exhibit up-regulation in response to accumulating proteins including A?1�42. Here, the ...
-enzymes to lysosomes, but it can also modulate the activity of a variety of extracellular M6P-glycoproteins ( ., latent. These derivatives could be used to favour the delivery of specific therapeutic compounds to lysosomes, notably in enzyme replacement therapies of lysosomal diseases or in neoplastic drug ...
, Madison, WI 53706, USA *Corresponding author: James D. Bangs, jdbangs@wisc.edu p67 is a lysosome-associated membrane protein�like lysosomal type I transmembrane glycoprotein in African trypanosomes. The p67 cytoplasmic domain (CD) is both necessary and sufficient for lysosomal targeting in pro- cyclic insect
SNAREs are required for specific membrane fusion throughout the endomembrane system. Here we report the characterization of rat ykt6, a prenylated SNARE selectively expressed in brain neurons. Immunofluorescence microscopy in neuronal and neuroendocrine cell lines revealed that membrane-associated ykt6 did not colocalize significantly with any conventional markers of ...
Autophagy is the cellular homeostatic pathway that delivers large cytosolic materials for degradation in the lysosome. Recent evidence indicates that autophagy mediates selective removal of protein aggregates, organelles and microbes in cells. Yet, the specificity in targeting a particular substrate to the autophagy pathway remains ...
The regulation and function of lysosomal hydrolases during yolk consumption and embryogenesis in zebrafish are poorly understood. In an effort to better define the lysosomal biochemistry of this organism, we analyzed the developmental expression, biochemical properties, and function of several glycosidases in zebrafish eggs, embryos, and adult tissues. Our ...
BackgroundProtein aggregation is a hallmark of many neurodegenerative diseases and has been linked to the failure to degrade misfolded and damaged proteins. In the cell, aberrant proteins are degraded by the ubiquitin proteasome system that mainly targets short-lived proteins, or by the lysosomes that mostly clear long-lived and poorly soluble proteins. ...
The potential for ecological toxicity associated with nanomaterials is a growing area of investigation, in particular in the aquatic environment. In suspension feeding invertebrates, the cellular immune system and digestive gland are likely to be targeted, due to their highly developed processes for the cellular internalisation of nano- and micro-scale particles that are ...
Lysosomal storage disorders (LSDs) constitute a diverse group of inherited diseases that result from lysosomal storage of compounds occurring in direct consequence to deficiencies of proteins implicated in proper lysosomal function. Pathology in the LSD mucolipidosis type IV (MLIV), is characterized by lysosomal ...
We have reported that clioquinol alters lysosome integrity, inhibits nuclear factor kappa B (NF-kappaB) activity, and induces apoptosis in human cancer cells. The present study investigated whether clioquinol targets both pathways dependently or independently in human prostate cancer DU 145 cells. Clioquinol inhibited NF-kappaB activity, an effect being ...
Natural killer (NK) cells target and kill aberrant cells, such as virally infected and tumorigenic cells. Killing is mediated by cytotoxic molecules which are stored within secretory lysosomes, a specialized exocytic organelle found in NK cells. Target cell recognition induces the formation of a lytic immunological synapse between the ...
... may be eliminated via a specific interaction with cell 44 surface receptors, followed by internalization and lysosomal degradation within the target ...
Center for Drug Evaluation (CDER)
The use of lysosome-targeted liposomes may significantly improve a delivery of therapeutic enzymes into lysosomes for the treatment of lysosome-associated diseases. The aim of this research was to achieve a specific intracellular targeting of lysosomes, by using liposomes modified with the ...
Proteins synthesized on membrane-bound ribosomes are sorted at the Golgi apparatus level for delivery to various cellular destinations: the plasma membrane or the extracellular space, and the lytic vacuole or lysosome. Sorting involves the assembly of vesicles, which preferentially package soluble proteins with a common destination. The selection of ...
l e t t e r s regulated AtP release from astrocytes through lysosome exocytosis Zhijun Zhang1 to selective labelling of lysosomes. Time-lapse confocal imaging of FM dye-labelled fluorescent puncta), demonstrated directly that extracellular ATP or glutamate induced partial exocytosis of lysosomes, whereas
