TY - JOUR. T1 - Regulators of lysosome function and dynamics in Caenorhabditis elegans. AU - Gee, Kevin. AU - Zamora, Danniel. AU - Horm, Teresa. AU - George, Laeth. AU - Upchurch, Cameron. AU - Randall, Justin. AU - Weaver, Colby. AU - Sanford, Caitlin. AU - Miller, Austin. AU - Hernandez, Sebastian. AU - Dang, Hope. AU - Fares, Hanna. N1 - Publisher Copyright: © 2017 Gee et al.. PY - 2017. Y1 - 2017. N2 - Lysosomes, the major membrane-bound degradative organelles, have a multitude of functions in eukaryotic cells. Lysosomes are the terminal compartments in the endocytic pathway, though they display highly dynamic behaviors, fusing with each other and with late endosomes in the endocytic pathway, and with the plasma membrane during regulated exocytosis and for wound repair. After fusing with late endosomes, lysosomes are reformed from the resulting hybrid organelles through a process that involves budding of a nascent lysosome, extension of the nascent lysosome from the hybrid organelle, while ...
Semantic Scholar extracted view of Histochemical indications for lysosomal localization of heavy metals in normal rat brain and liver. by Annika Brun et al.
Diril, M. K., Schmidt, S., Krauß, M., Gawlik, V., Joost, H.-G., Schürmann, A., Haucke, V. and Augustin, R. (2009), Lysosomal localization of GLUT8 in the testis - the EXXXLL motif of GLUT8 is sufficient for its intracellular sorting via AP1- and AP2-mediated interaction. The FEBS Journal, 276: 3729-3743. doi: 10.1111/j.1742-4658.2009.07089.x ...
View Notes - Lecture 13 11 from BICD 110 at UCSD. Lecture 13 11/02/07 Golgi Structure/Function, Lysosome, Exocytosis Glycosylation Protects lysosome membrane proteins from autodegradation
Recent data both from cell-free experiments and from cultured cells have shown that lysosomes can fuse directly with late endosomes to form a hybrid organelle. This has a led to a hypothesis that dense core lysosomes are in essence storage granules for acid hydrolases and that, when the former fuse with late endosomes, a hybrid organelle for digestion of endocytosed macromolecules is created. Lysosomes are then re-formed from hybrid organelles by a process involving condensation of contents. In this Commentary we review the evidence for formation of the hybrid organelles and discuss the current status of our understanding of the mechanisms of fusion and lysosome re-formation. We also review lysosome biosynthesis, showing how recent studies of lysosome-like organelles including the yeast vacuole, Drosophila eye pigment granules and mammalian secretory lysosomes have identified novel proteins involved in this process. ...
Lysosomes degrade and recycle transported cellular components and internalized material by fusing with autophagosomes, phagosomes, and late endosomes. The resulting lysosomal breakdown products are used to generate new macromolecules and to provide energy in response to the nutritional needs of the cell. Recently, lysosome functions were expanded to include roles in nutrient sensing and energy metabolism (4). In this study, we report that the exposure of macrophages to LPS or heat-killed bacteria raises AGS3 levels. The increases in AGS3 reduced signaling through the mTOR pathway. However, in a nutrient-replete state this did not lead to a substantive increase in autophagy, but it did facilitate the nuclear translocation of TFEB, which transcriptionally activates many of the genes involved in lysosomal biogenesis and function. The subsequent increase in lysosomal biogenesis/function helped macrophages to resist intracellular infections by several strains of antibiotic-resistant ...
In many cases, apoptosis may be initiated by a minor lysosomal destabilization, which some time later is followed by a secondary, more pronounced, lysosomal rupture. After exposure to low concentrations of sphingosine, a lysosomotropic detergent, Jurkat and J774 cells underwenr apoptotic cell death, while cells exposed to higher concentrations of this agent showed necrosis. Sphingosine-induced apoptosis was partly prevented by the inhibitors of lysosomal aspartic or cysteine proteases, pepstatin A or E64d. Under these conditions, caspase-3 like activity was reduced 40-55%, suggesting that lysosomal enzymes could be upstream activators of caspase-3.. In J774 cells over-expressing Bcl-2, the early oxidant-induced lysosomal destabilization takes place, but the delayed secondary lysosomal rupture and ensuing apoptosis are both suppressed. Phosphorylation of Bcl-2 seems to be required for this anti-apoptotic effect because the protection is amplified by pre-treatment with phorbol 12-myristate ...
Lysosomes are one of the major degradative organelles in eukaryotic cells that carry out diverse cellular functions. Lysosomes show highly dynamic behaviors, including homotypic and heterotypic fusions, fission, and formation/reformation, which itself involves budding, extension, and scission. We carried out an unbiased forward mutational screen to identify novel regulators of lysosome dynamics and/or function; this screen is based on the degradation of a substrate, GFP, that is endocytosed by scavenger cells in worms. We identified cup-5 and six additional proteins that have lysosomal functions in C. elegans coelomocytes. CUP-16 is only conserved in the genus Caenorhabditis, and likely functions in endocytic uptake at the plasma membrane and in lysosomal degradation. Besides CUP-16, five of the mammalian homologs of the other CUP proteins, CIC-7, OSTM1, PLEKHM1, Cystinosin, and TRPML1, had been previously implicated in lysosome biology, thus validating this approach (Bach 2001; Lange et al. ...
The mechanisms involved in radiation-induced cellular injury and death remain incompletely understood. In addition to the direct formation of highly reactive hydroxyl radicals (HO.) by radiolysis of water, oxidative stress events in the cytoplasm due to formation of H2O2 may also be important. Since the major pool of low-mass redox-active intracellular iron seems to reside within lysosomes, arising from the continuous intralysosomal autophagocytotic degradation of ferruginous materials, formation of H2O2 inside and outside these organelles may cause lysosomal labilization with release to the cytosol of lytic enzymes and low-mass iron. If of limited magnitude, such release may induce reparative autophagocytosis, causing additional accumulation of redox-active iron within the lysosomal compartment. We have used radio-resistant histiocytic lymphoma (J774) cells to assess the importance of intralysosomal iron and lysosomal rupture in radiation-induced cellular injury. We found that a 40 Gy ...
The exact mechanism by which the atherogenic lipids oxLDL and CC perturb lysosomal function is not known. Oxidized LDL is taken up by macrophage scavenger receptors and is trafficked to the endolysosomal compartment. Oxidized LDL can then bind and inactivate cathepsins with high affinity,30 inactivate other proteases including the Naβ Gases,31 and produce a form of apolipoproteinB that is highly resistant to hydrolysis.32,33 OxLDL has also been demonstrated in endothelial and smooth muscle cells to inhibit activity and expression of the enzyme crucial to cholesterol ester hydrolysis, LIPA.34 Most recently, the formation of cholesterol microcrystals and ensuing disruption of lysosomal integrity has directly been linked to the buildup of oxLDL in the lysosomal compartment.14 Such a mechanism would favor the notion that the mechanism of lysosomal dysfunction mediated by oxLDL and larger CC lies in a continuum (with the oxLDL pool eventually precipitating as insoluble crystals). Our data support ...
TY - JOUR. T1 - FIG4 regulates lysosome membrane homeostasis independent of phosphatase function. AU - Bharadwaj, Rajnish. AU - Cunningham, Kathleen M.. AU - Zhang, Ke. AU - Lloyd, Thomas E.. N1 - Funding Information: The MPI Imaging Core is funded by an NINDS Core Center Grant (P30 NS050274: JHU Center for Neuroscience Research). This work was supported by an NIH/NINDS R01NS082563 to T.E.L. and an ALSA fellowship to K.Z.. PY - 2016. Y1 - 2016. N2 - FIG4 is a phosphoinositide phosphatase that is mutated in several diseases including Charcot-Marie-Tooth Disease 4J (CMT4J) and Yunis-Varon syndrome (YVS). To investigate the mechanism of disease pathogenesis, we generated Drosophila models of FIG4-related diseases. Fig4 null mutant animals are viable but exhibit marked enlargement of the lysosomal compartment in muscle cells and neurons, accompanied by an age-related decline in flight ability. Transgenic animals expressing Drosophila Fig4 missense mutations corresponding to human pathogenic ...
One contributing factor to the increased ability of more stable antigens to elicit immune responses is that the restricted susceptibility to lysosomal proteolysis favored the production of peptide-MHC class II complexes by DCs, at least in vitro (Fig. 2 E and Fig. 4 D). In addition, and just as important in an in vivo setting, we found that the increased stability to lysosomal proteolysis also favored the retention of antigens captured by DCs to lymphoid organs. 16 h after a single intradermal injection, the stable forms of RNase (Alexa 488-RNase-A) could be detected in CD11c+ DCs in the draining lymph nodes (Fig. 1 D). In contrast, the rapidly degraded form (Alexa 647-RNase-S) was barely detectable under the same conditions (Fig. 1 D). Combined with the fact that differential immunogenicity was observed by adoptively transferring DCs containing either RNase-A or RNase-S (Fig. 2 D), these results strongly suggest that at least one effect of decreased susceptibility to proteolysis is to ...
article{9e6ef65e-280f-480c-95c2-8ec585bac8f7, abstract = {Secretory lysosomes of natural killer (NK) cells combine storage, regulated secretion and lysosomal activity. We asked whether one could target exogenous proteins to the secretory lysosomes of NK-cells for final delivery into a tumor site upon degranulation. cDNAs for both soluble and transmembrane (tm) proteins were expressed in the human YT-Indy NK-cell line. Targeting of a soluble TNF receptor (sTNFR1) was achieved by expressing a cDNA construct with a transmembrane sequence to facilitate ER-export and by incorporating a cytosolic sorting signal (Y) from CD63 to overcome constitutive secretion. The resulting sTNFR1-tm-Y was targeted to secretory lysosomes as confirmed by results from biosynthetic radiolabeling in combination with subcellular fractionation, immunoelectron microscopy, and immunofluorescence microscopy. A soluble sTNFR1 form was generated in the secretory lysosome by endogenous proteolytic activity. Expression of ...
The Pryor lab is a cell biology group that is interested in the biogenesis of lysosomes and phagolysosomes, the role of lysosomes in disease and additionally how lysosomes are manipulated by intracellular pathogens.. 1. Lysosome Biogenesis. The lysosome was traditionally regarded as a dead-end hydrolytic organelle for the recycling of waste products. However, in recent years our understanding of the lysosome has changed and it is now clear that the lysosome is a signalling hub and is crucial for cellular homeostasis. Lysosome dysfunction can lead to diseases such as cancer, neurodegeneration and obesity. One overarching theme to our research are the molecules involved in regulating lysosome function. Projects are currently investigating chaperone mediated autophagy and lysosome biogenesis by transcription factors.. ...
Villamil Giraldo AM, Fyrner T, Wennmalm S, Parikh AN, Öllinger K, Ederth T Langmuir 32 (50) 13566-13575 [2016-12-20; online 2016-12-13] Lysosomotropic detergents (LDs) selectively rupture lysosomal membranes through mechanisms that have yet to be characterized. A consensus view, currently, holds that LDs, which are weakly basic, diffuse across cellular membranes as monomers in an uncharged state, and via protonation in the acidic lysosomal compartment, they become trapped, accumulate, and subsequently solubilize the membrane and induce lysosomal membrane permeabilization. Here we demonstrate that the lysosomotropic detergent O-methyl-serine dodecylamide hydrochloride (MSDH) spontaneously assembles into vesicles at, and above, cytosolic pH, and that the vesicles disassemble as the pH reaches 6.4 or lower. The aggregation commences at concentrations below the range of those used in cell studies. Assembly and disassembly of the vesicles was studied via dynamic light scattering, zeta potential ...
The lack or complexity of high resolution technologies and the need for labelled compound derivatives represents a major limitation on the study of intracellular distribution dynamics of pharmacological agents. The intrinsic, label-free and organelle-specific fluorescence activity of nintedanib presented in this study provides a powerful tool to dissect intracellular accumulation and distribution dynamics of this clinically approved small molecule TKI. The observation that lysosomal alkalization via V-ATPase inhibition sensitized lung cancer cells towards nintedanib suggests that protonation-based lysosomal sequestration represents a cell-intrinsic protection mechanism against this FGFR inhibitor. In accordance, various chemotherapeutic agents including doxorubicin, mitoxantrone and vincristine but also TKIs such as gefitinib, lapatinib and sunitinib have been reported to be subject to inactivating lysosomal sequestration [23, 30]. Together, these findings support a yet underestimated central ...
n animal regeneration, control of position-dependent cell proliferation is crucial for the complete restoration of patterned appendages in terms of both, shape and size. However, detailed mechanisms of this process are largely unknown. In this study, we identified leucine/glutamine and v-ATPase/lysosomal acidification, via mechanistic target of rapamycin complex 1 (mTORC1) activation, as effectors of amputation plane-dependent zebrafish caudal fin regeneration. mTORC1 activation, which functions in cell proliferation, was regulated by lysosomal acidification possibly via v-ATPase activity at 3 h post amputation (hpa). Inhibition of lysosomal acidification resulted in reduced growth factor-related gene expression and suppression of blastema formation at 24 and 48 hpa, respectively. Along the proximal-distal axis, position-dependent lysosomal acidification and mTORC1 activation were observed from 3 hpa. We also report that Slc7a5 (L-type amino acid transporter), whose gene expression is ...
EIPA-modulated retrograde movement of lysosomes depended on the activity of Rab7, a GTPase known to traffic late endosomes and lysosomes towards the nucleus (Johansson et al., 2007) and the Rab7 effector RILP, which is similar to the mechanism of Troglitazone-induced retrograde lysosome trafficking (Steffan and Cardelli, 2010). In fact, lysosomes in Rab7-KD- and DN-RILP-expressing cells were more peripherally located than in vector control cells. Also, HGF-induced invasion by Rab7-KD cells was not blocked by EIPA, in contrast to control cells. Finally, Fig. 6 demonstrates that Rab7-KD cells were more invasive and secreted more cathepsin B than control cells in the absence of HGF. We conclude that a more peripheral cellular location of lysosomes may be important in regulating invasion, and that EIPA blocks invasion by stimulating retrograde lysosome transport or preventing anterograde movement.. In support of this idea, overexpression of WT-RILP induced lysosome aggregation near the nucleus and ...
We have followed the transfer of EGF-EGF receptor (EGFR) complexes from endosomal vacuoles that contain transferrin receptors (TfR) to lysosome vacuoles identified by their content of HRP loaded as a 15-min pulse 4 h previously. We show that the HRP-loaded lysosomes are lysosomal-associated membrane protein-1 (LAMP-1) positive, mannose-6-phosphate receptor (M6PR) negative. and contain active acid hydrolase. EGF-EGFR complexes are delivered to these lysosomes intact and are then rapidly degraded. Preactivating the HRP contained within the preloaded lysosomes inhibits the delivery of EGFR and degradation of EGF, and results in the accumulation of EGFR-containing multivesicular bodies (MVB). With time these accumulating MVB undergo a series of maturation changes that include the loss of TfR, the continued recruitment of EGFR, and the accumulation of internal vesicles, but they remain LAMP-1 and M6PR negative. The mature MVB are often seen to make direct contact with lysosomes containing ...
Cellular clearance is a fundamental process required by the cells of every species. In eukaryotes, most of the cellular clearing processes occur in a specialized organelle, the lysosome. Given that the requirements of the degradative machinery in a cell may vary depending on tissue type, age and environmental conditions, we postulated that a system coordinates lysosomal activity and that lysosomal function is subject to transcriptional regulation. Using a systems biology-based approach, we discovered a gene regulatory network (CLEAR: Coordinated Lysosomal Enhancement And Regulation) that controls lysosomal biogenesis and function (Sardiello et al, Science 2009) and a master gene, the bHLH-leucine zipper transcription factor TFEB, which binds to CLEAR target sites in the promoter of lysosomal genes and positively regulates their expression (Sardiello et al, Science 2009). TFEB overexpression induces lysosomal biogenesis and increases the cells ability to degrade complex molecules such as mutated ...
Settembre C., Zoncu R., Medina D.L., Vetrini F., Erdin S., Erdin S., Huynh T., Ferron M., Karsenty G., Vellard M.C., Facchinetti V., Sabatini D.M., Ballabio A.. The lysosome plays a key role in cellular homeostasis by controlling both cellular clearance and energy production to respond to environmental cues. However, the mechanisms mediating lysosomal adaptation are largely unknown. Here, we show that the Transcription Factor EB (TFEB), a master regulator of lysosomal biogenesis, colocalizes with master growth regulator mTOR complex 1 (mTORC1) on the lysosomal membrane. When nutrients are present, phosphorylation of TFEB by mTORC1 inhibits TFEB activity. Conversely, pharmacological inhibition of mTORC1, as well as starvation and lysosomal disruption, activates TFEB by promoting its nuclear translocation. In addition, the transcriptional response of lysosomal and autophagic genes to either lysosomal dysfunction or pharmacological inhibition of mTORC1 is suppressed in TFEB-/-cells. Interestingly, ...
The lysosomal acidification defect linked to cytotoxicity of mutations in the P-type ATPase ATP13A2/PARK9 in Parkinsons disease (PD) prompts comparison to the similar mechanism operating in AD due to mutations of presenilin 1. Dehay and colleagues used nearly the same extensive battery of methods as Lee et al. (2010) to evaluate autophagy and lysosomal function in fibroblasts from PD patients and other model cell systems. While the two studies implicate different lysosomal constituents in these two diseases, they reveal pathogenic mechanisms involving defects in lysosome function that are remarkably similar and mutually validating. In both diseases, a lysosomal component needed for acidification is prematurely degraded in the endoplasmic reticulum and fails to reach the lysosome in amounts required for full function. In early onset AD caused by mutations of PS1, the V01a subunit of the proton pump vATPase is improperly chaperoned by the mutant PS1 and is degraded during its exit from the ER, ...
The CE moiety in Ox-LDL is hydrolyzed normally in lysosomes, but the resulting UC is trapped in the lysosomes secondary to the effect of oxysterols that are present in Ox-LDL.5 However, the mechanism responsible for trapping UC in the lysosomes has not been explored. Since SM binds UC with high affinity,18 19 20 21 22 the goal of this study was to examine whether SM accumulates in the macrophage lysosomes following cell incubation with Ox-LDL and whether SM accumulation can be responsible for trapping of the lipoprotein UC in the macrophage lysosomes. The present study indeed showed that Ox-LDL-derived SM accumulates in lysosomes as a result of an impaired SM hydrolysis by the lysosomal SMase. We also demonstrated that 7-KC, the major oxidized cholesterol derivative in Ox-LDL,5 40 41 is a potent inhibitor of macrophage lysosomal SMase. This oxysterol can thus lead to the lysosomal accumulation of Ox-LDL-derived UC secondary to SM accumulation in the macrophage lysosomes.. The mechanisms whereby ...
TY - JOUR. T1 - Intramitochondrial recruitment of endolysosomes mediates Smac degradation and constitutes a novel intrinsic apoptosis antagonizing function of XIAP E3 ligase. AU - Hamacher-Brady, Anne. AU - Choe, S. C.. AU - Krijnse-Locker, J.. AU - Brady, Nathan Ryan. PY - 2014/12/1. Y1 - 2014/12/1. N2 - Intrinsic apoptosis involves BH3-only protein activation of Bax/Bak-mediated mitochondrial outer membrane permeabilization (MOMP). Consequently, cytochrome c is released from the mitochondria to activate caspases, and Smac (second mitochondria-derived activator of caspases) to inhibit XIAP-mediated caspase suppression. Dysfunctional mitochondria can be targeted for lysosomal degradation via autophagy (mitophagy), or directly through mitochondria-derived vesicle transport. However, the extent of autophagy and lysosomal interactions with apoptotic mitochondria remains largely unknown. We describe here a novel pathway of endolysosomal processing of mitochondria, activated in response to canonical ...
The endolysosomal system and autophagy are essential components of macromolecular turnover in eukaryotic cells. The low-abundance signaling lipid PI(3,5)P2 is a key regulator of this pathway. Analysis of mouse models with defects in PI(3,5)P2 biosynthesis has revealed the unique dependence of the mammalian nervous system on this signaling pathway. This insight led to the discovery of the molecular basis for several human neurological disorders, including Charcot-Marie-Tooth disease and Yunis-Varon syndrome. Spontaneous mutants, conditional knockouts, transgenic lines, and gene-trap alleles of Fig4, Vac14, and Pikfyve (Fab1) in the mouse have provided novel information regarding the role of PI(3,5)P2in vivo. This review summarizes what has been learned from mouse models and highlights the utility of manipulating complex signaling pathways in vivo.
A cells digestive enzymes are enclosed in a membrane bound organelle. How can these molecules funtion in the cell? The KGB Agent answer: This membrane bound organelle is the lysosome that contains an array of enzymes capable of breaking down all types of biological polymers-proteins, nucleic acids, carbohydrates, and lipids. Lysosomes function as the digestive system of the cell, serving both to degrade material taken up from outside the cell and to digest obsolete components of the cell itself. In their simplest form, lysosomes are visualized as dense spherical vacuoles, but they can display considerable variation in size and shape as a result of differences in the materials that have been taken up for digestion. Lysosomes thus represent morphologically diverse organelles defined by the common function of degrading intracellular material. You will find lysosomes in nearly every animal-like eukaryotic cell. Lysosomes hold enzymes that were created by the cell. What creates a lysosome? Youll have
The rapid activation of the mechanistic target of rapamycin complex-1 (mTORC1) by growth factors is increased by extracellular amino acids through yet-undefined mechanisms of amino acid transfer into endolysosomes. Because the endocytic process of macropinocytosis concentrates extracellular solutes into endolysosomes and is increased in cells stimulated by growth factors or tumor-promoting phorbol esters, we analyzed its role in amino acid-dependent activation of mTORC1. Here, we show that growth factor-dependent activation of mTORC1 by amino acids, but not glucose, requires macropinocytosis. In murine bone marrow-derived macrophages and murine embryonic fibroblasts stimulated with their cognate growth factors or with phorbol myristate acetate, activation of mTORC1 required an Akt-independent vesicular pathway of amino acid delivery into endolysosomes, mediated by the actin cytoskeleton. Macropinocytosis delivered small, fluorescent fluid-phase solutes into endolysosomes sufficiently fast to ...
The cytotoxic activity of activated macrophages against tumorigenic target cells appears to be mediated by lysosomal enzymes of activated macrophage origin. Lysosomes of activated macrophages are secreted directly into the cytoplasm of susceptible target cells, which subsequently undergo heterolysis. This reaction can be inhibited by agents which prevent the exocytosis of macrophage lysosomes (hydrocortisone) or which interfere with the action of lysosomal enzymes (trypan blue). ...
TY - JOUR. T1 - The mannose 6-phosphate receptor and the biogenesis of lysosomes. AU - Griffiths, Gareth. AU - Hoflack, Bernard. AU - Simons, Kai. AU - Mellman, Ira. AU - Kornfeld, Stuart. PY - 1988/2/12. Y1 - 1988/2/12. N2 - Localization of the 215 kd mannose 6-phosphate receptor(MPR) was studied in normal rat kidney cells. Low levels of receptor were detected in the trans Golgi network, Golgi stack, plasma membrane, and peripheral endosomes. The bulk of the receptor was localized to an acidic, reticular-vesicular structure adjacent to the Golgi complex. The structure also labeled with antibodies to lysosomal enzymes and a lysosomal membrane glycoprotein (Igp120). While lysosome-like, this structure is not a typical lysosome that is devoid of MPRs. The endocytic marker α2macroglobulin-gold entered the structure at 37°C, but not at 20°C. With prolonged chase, most of the marker was transported from the structure into lysosomes. We propose that the MPR/Igp-enriched structure is a specialized ...
Although the pathogenesis of Parkinsons disease (PD) is considered multifactorial, evidence from genetics and cell biology has implicated specific molecular pathways. This article summarizes evidence that suggests that the level of intracellular alpha-synuclein is critical for the onset of neurodegeneration with Lewy bodies and dependent, to a large extent, on lysosomal degradation. The function of other key proteins that emerged from genetics is discussed: Pink1 and Parkin regulate the degradation of damaged mitochondria by the lysosome (mitophagy). Glucocerebrosidase and ATP13A2 are important components of this degradative organelle. VPS35 and LRRK2 may regulate trafficking within lysosome-dependent pathways, such as autophagy and endosomal vesicle recycling. Clinically, diffuse alpha-synucleinopathy or dementia seems to correlate with mutations which interfere with the broader function of lysosomal pathways, whereas a predominantly motor syndrome and nigrostriatal degeneration is associated with
The present experiments demonstrate that, just as for yeast cell-free homotypic vacuole fusion (Peters and Mayer 1998), cell-free heterotypic fusion of mammalian late endosomes and lysosomes requires Ca2+, probably mediating its effects via calmodulin. The Ca2+ is derived from the organelle lumen and is required at a late step in fusion after the requirement for a rab protein.. While the observation that BAPTA inhibits late endosome-lysosome membrane fusion with an IC50 of ∼2 mM, although EGTA has no effect even at 5 mM, is at first sight surprising, it is not without precedent in vertebrate membrane fusion systems. Thus, cell-free nuclear vesicle fusion during nuclear envelope assembly was shown to be inhibited by 5 mM BAPTA but unaffected by 12 mM EGTA (Sullivan et al. 1993). This effect was explained by the fact that at physiological pH, BAPTA exchanges Ca2+ ∼100 times faster than EGTA, reflecting faster rates of association and dissociation. Therefore, facilitated diffusion can cause ...
The CLEAR consensus sequence overlaps that of the E-box (CANNTG), a known target site for basic helix-loop-helix (bHLH) transcription factors (4). In particular, members of the microphthalmia-transcription factor E (MiT/TFE) subfamily of bHLH factors were found to bind sequences similar to the CLEAR consensus (5). The MiT/TFE subfamily is composed of four members in humans: MITF, TFE3, TFEB, and TFEC (6). To determine whether any of these proteins are able to modulate the expression of lysosomal genes, we transfected HeLa cells with plasmids carrying MITF, TFE3, TFEB, or TFEC cDNAs. We observed an increase in the mRNA levels of lysosomal genes (22 out of 23 genes tested) only after TFEB overexpression (Fig. 1C). Accordingly, we detected a significant increase in the activities of lysosomal enzymes β-glucosidase, Cathepsin D, and β-glucuronidase (fig. S5). Induction of lysosomal genes after TFEB overexpression was also observed in human embryonic kidney (HEK) 293 cells (fig. S6). We predicted ...
Lysosomes are small structures inside cells that specialize in breaking down unwanted proteins and other cellular components. These waste components could potentially damage or kill the cell. One biochemical process that lysosomes use to accomplish their task is called the autophagic-lysosomal pathway. Malfunction of lysosomes in general, and the autophagic-lysosomal pathway in particular, have been implicated in several neurodegenerative disorders, including Alzheimers disease. Impaired lysosomal function can lead to the overproduction of beta-amyloid from its parent molecule, amyloid precursor protein (APP). Beta-amyloid is a protein fragment closely linked to Alzheimers pathology. Recent studies have found that the production and activities of lysosomes are partly regulated by a transcription factor called TFEB. Transcription factors affect cellular activity by influencing how genes are expressed in the cells. In preliminary experiments, Abhinav Diwan, M.D., and colleagues have observed ...
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The microphthalmia family of transcription factors (MiT/TFEs) controls lysosomal biogenesis and is negatively regulated by the nutrient sensor mTORC1. However, the mechanisms by which cells with constitutive mTORC1 signaling maintain lysosomal catabolism remain to be elucidated. Using the murine epidermis as a model system, we found that epidermal Tsc1 deletion resulted in a phenotype characterized by wavy hair and curly whiskers, and was associated with increased EGFR and HER2 degradation. Unexpectedly, constitutive mTORC1 activation with Tsc1 loss increased lysosomal content via upregulated expression and activity of MiT/TFEs, whereas genetic deletion of Rheb or Rptor or prolonged pharmacologic mTORC1 inactivation had the reverse effect. This paradoxical increase in lysosomal biogenesis by mTORC1 was mediated by feedback inhibition of AKT, and a resulting suppression of AKT-induced MiT/TFE downregulation. Thus, inhibiting hyperactive AKT signaling in the context of mTORC1 loss-of-function ...
In metazoans, lysosomes are characterized by a unique tubular morphology, acidic pH, and specific membrane protein (LAMP) and lipid (cholesterol) composition as well as a soluble protein (hydrolases) composition. Here we show that perturbation to the eye-color gene, light, results in impaired lysosomal acidification, sterol accumulation, altered endosomal morphology as well as compromised lysosomal degradation. We find that Drosophila homologue of Vps41, Light, regulates the fusion of a specific subset of biosynthetic carriers containing characteristic endolysosomal membrane proteins, LAMP1, V0-ATPase and the cholesterol transport protein, NPC1, with the endolysosomal system, and is then required for the morphological progression of the multivesicular endosome. Inhibition of Light results in accumulation of biosynthetic transport intermediates that contain these membrane cargoes, whereas under similar conditions, endosomal delivery of soluble hydrolases, previously shown to be mediated by Dor, ...
Autophagy is of importance in the regulation of cell differentiation and senescence in podocytes, the highly differentiated glomerular epithelial cells. It is possible that derangement of autophagy under different pathological conditions activates or enhances Epithelial-to-Mesenchymal Transition (EMT) in podocytes, resulting in glomerular sclerosis. To test this hypothesis, the present study produced lysosome dysfunction by inhibition of vacuolar- type H+-ATPase (V-ATPase) to test whether deficiency of autophagic flux enhances EMT in podocytes. By Western blot analysis, inhibition of lysosome function by V-ATPase inhibitor or its siRNA was found to induce a significantly enhanced EMT in cultured podocytes, as shown by marked decreases in P-cadherin (P-cad) and zonula occludens-1 (ZO-1) as epithelial markers and simultaneous increases in the mesenchymal markers, fibroblast specific protein-1 (FSP-1) and α-smooth muscle actin (α-SMA). These changes in EMT markers were confirmed by confocal microcopy.
Nonselective cation channel probably playing a role in the regulation of membrane trafficking events and of metal homeostasis (PubMed:29019981). Proposed to play a major role in Ca(2+) release from late endosome and lysosome vesicles to the cytoplasm, which is important for many lysosome-dependent cellular events, including the fusion and trafficking of these organelles, exocytosis and autophagy. Required for efficient uptake of large particles in macrophages in which Ca(2+) release from the lysosomes triggers lysosomal exocytosis. May also play a role in phagosome-lysosome fusion (PubMed:23993788, PubMed:27623384). Involved in lactosylceramide trafficking indicative for a role in the regulation of late endocytic membrane fusion/fission events. By mediating lysosomal Ca(2+) release is involved in regulation of mTORC1 signaling and in mTOR/TFEB-dependent lysosomal adaptation to environmental cues such as nutrient levels (PubMed:25733853). Seems to act as lysosomal active oxygen species (ROS) sensor
Exploring the mechanism of the drugs cancer-preventing action provided some intriguing insights.. At the doses used in the new study, which were similar to those needed to prevent malaria, chloroquine triggered the death of premalignant cells. This suggests that within the context of MYC overexpression, the drug induces apoptotic cell death-programmed cell death-in response to ineffective autophagic protein degradation and lysosomal changes in the cell. (Lysosomes are cellular recycling centers that degrade old and unwanted material in the cell and recycle building blocks that are used for cell growth.) The p53 protein can induce apoptosis in response to DNA damage or stress, and the studys results suggest that alterations in lysosomal function trigger a p53-dependent cell death response. Our studies have established that chloroquine inhibits a late step in the autophagy pathway by inhibiting lysosome functions that provide necessary material used to keep tumor cells alive under times of ...
By using video microscopy with fluorescent tagging of the two organelles, the scientists observed that the mitochondria and lysosomes formed stable contacts inside living human cells. The authors also employed other advanced imaging techniques - including electron microscopy and super-resolution imaging - to discover that the formation, and subsequent loosening, of these contacts is regulated by a lysosomal protein called RAB7.. The discovery of these mitochondria-lysosome contacts is extremely exciting, said first author Yvette Wong, PhD, a postdoctoral fellow in Kraincs laboratory. We now show that these contacts offer a potential site through which mitochondria and lysosomes can crosstalk, and it suggests that defects in the regulation of this contact site may drive the pathogenesis of various human diseases.. In follow-up studies, the scientists are now investigating how dysfunction of the proteins that tether mitochondria and lysosomes together may affect the function of the ...
In the cell, the proteasome and lysosomes represent the most important proteolytic machineries, responsible for the protein degradation in the ubiquitin-proteasome system (UPS) and autophagy, respectively. Both the UPS and autophagy are essential to protein quality and quantity control. Alterations …
TY - JOUR. T1 - Cationic lipids delay the transfer of plasmid DNA to lysosomes. AU - Wattiaux, R.. AU - Jadot, M.. AU - Laurent, N.. AU - Dubois, F.. AU - Wattiaux-De Coninck, Simone. N1 - Medline is the source for the MeSH terms of this document.. PY - 1996/10/14. Y1 - 1996/10/14. N2 - Plasmid S DNA, naked or associated with different cationic lipid preparations was injected to rats. Subcellular distribution of radioactivity in the liver one hour after injection, was established by centrifugation methods. Results show that at that time, S DNA has reached lysosomes. On the contrary, when S DNA was complexed with lipids, radioactivity remains located in organelles whose distribution after differential and isopycnic centrifugation, is clearly distinct from that of arylsulfatase, a lysosome marker enzyme. Injection of Triton WR 1339, a specific density perturbant of lysosomes, four days before S DNA injection causes a density decrease of radioactivity bearing structures, apparent one hour after ...
Synopsis: The realization of new technologies and the development of targeted biopharmaceutical therapies have accelerated in the last decade with over 30 such compounds currently in clinical trials. With ongoing development and evaluation of strategies, such as antibody drug conjugates, to effectively deliver compounds to targeted cell populations through the endocytic-lysosomal pathway, the development and availability of novel reagents will become paramount. Isolated rat hepatic tritosomes and human hepatic lysosomes are in vitro systems that can be utilized to quickly and conveniently evaluate compound stability and guide development direction of biopharmaceutical candidates. In this study, subcellular isolation techniques combined with immunoblotting, protease arrays, and enzymatic activity assays were carried out to characterize isolated rat tritosomes and human hepatic lysosomes ...
INTRODUCTION. Lysosomes are round, film bound organelles that are created by the Golgi mechanical assembly. They contain hydrolytic proteins, thus work as a component of the reusing arrangement of the cell. In this article, I will take a gander at the structure, blend, and capacity of lysosomes, and we will think about their pertinence to clinical practice. Structure Lysosomes are acidic film bound organelles found inside cells, as a rule around 1 micrometer long. Lysosomes contain various hydrolytic proteins that catalyze hydrolysis responses. The layer encompassing the lysosome is crucial to guarantee these catalysts dont spill out into the cytoplasm and harm the cell from inside. So as to keep up the acidic pH of the lysosome, protons are effectively moved into the organelle over the lysosomal film. Combination The lysosome and the chemicals inside it are integrated independently. Lysosomal proteins are shaped similarly to some other protein. The initial step is the commencement of mRNA ...
The lysosomes are used for the digestion of macromolecules from phagocytosis (ingestion of other dying cells or larger extracellular material), endocytosis (where receptor proteins are recycled from the cell surface), and autophagy (where old or unneeded organelles or proteins, or microbes which have invaded the cytoplasm are delivered to the lysosome). Autophagy may also lead to autophagic cell death, a form of programmed self-destruction, or autolysis, of the cell, which means that the cell is digesting itself. Other functions include digesting foreign bacteria (or other forms of waste) that invade a cell and helping repair damage to the plasma membrane by serving as a membrane patch, sealing the wound. Lysosomes also do much of the cellular digestion required to digest tails of tadpoles and to remove the web from the fingers of a 3-6 month old fetus. This process of programmed cell death is called apoptosis.[1] ...
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The mechanisms by which altered processing, distribution and secretion of proteolytic enzymes occur, facilitating degradation of the extracellular matrix in invasive and metastatic cells, are not fully understood. Studies on the MCF-10 A breast epithelial cell line and its premalignant, c-Ha-ras-transfected MCF-10AneoT counterpart have shown that the ras-transfected cell line has a more alkaline pH. The objective of this study was to determine which organelles of the endosome-lysosome route were alkalinized and shifted to the cell periphery after ras-transfection. Antibodies to the hapten 2,4-dinitrophenyl (DNP), required for pH studies, were raised in rabbits and chickens using DNP-ovalbumin (DNP-OVA) as immunogen. Cationised DNP-OVA (DNP-catOVA) was also inoculated to increase antibody titres. Anti-hapten and carrier antibody titres were assessed. In rabbits, cationisation seems useful to increase anti-DNP titres if a non-self carrier protein (OVA) is used. In chickens, cationisation of ...
TY - JOUR. T1 - Lysosomal dysfunction causes neurodegeneration in mucolipidosis II knock-in mice. AU - Kollmann, K.. AU - Damme, M.. AU - Markmann, S.. AU - Morelle, W.. AU - Schweizer, M.. AU - Hermans-Borgmeyer, I.. AU - Röchert, A. K.. AU - Pohl, S.. AU - Lübke, T.. AU - Michalski, J. C.. AU - Käkelä, R.. AU - Walkley, S. U.. AU - Braulke, T.. PY - 2012/9. Y1 - 2012/9. N2 - Mucolipidosis II is a neurometabolic lysosomal trafficking disorder of infancy caused by loss of mannose 6-phosphate targeting signals on lysosomal proteins, leading to lysosomal dysfunction and accumulation of non-degraded material. However, the identity of storage material and mechanisms of neurodegeneration in mucolipidosis II are unknown. We have generated knock-in mice with a common mucolipidosis II patient mutation that show growth retardation, progressive brain atrophy, skeletal abnormalities, elevated lysosomal enzyme activities in serum, lysosomal storage in fibroblasts and brain and premature death, ...
TY - JOUR. T1 - Eps8 is recruited to lysosomes and subjected to chaperone-mediated autophagy in cancer cells. AU - Welsch, Thilo. AU - Younsi, Alexander. AU - Disanza, Andrea. AU - Rodriguez, Jose Antonio. AU - Cuervo, Ana Maria. AU - Scita, Giorgio. AU - Schmidt, Jan. N1 - Funding Information: We would like to thank Sonja Bauer for her excellent technical assistance. This work was partly supported by the NIH Grant AG021904 (to AMC). PY - 2010/7. Y1 - 2010/7. N2 - Eps8 controls actin dynamics directly through its barbed end capping and actin-bundling activity, and indirectly by regulating Rac-activation when engaged into a trimeric complex with Eps8-Abi1-Sos1. Recently, Eps8 has been associated with promotion of various solid malignancies, but neither its mechanisms of action nor its regulation in cancer cells have been elucidated. Here, we report a novel association of Eps8 with the late endosomal/lysosomal compartment, which is independent from actin polymerization and specifically occurs in ...
Coat proteins appear to play a general role in intracellular protein trafficking by coordinating a membrane budding event with cargo selection. Here we show that the AP-2 adaptor, a clathrin-associated coat-protein complex that nucleates clathrin-coated vesicle formation at the cell surface, can also initiate the assembly of normal polyhedral clathrin coats on dense lysosomes under physiological conditions in vitro. Clathrin coat formation on lysosomes is temperature dependent, displays an absolute requirement for ATP, and occurs in both semi-intact cells and on purified lysosomes, suggesting that clathrin-coated vesicles might regulate retrograde membrane traffic out of the lysosomal compartment. ...
Chloroquine (CQ) or hydroxychloroquine [4]. The results suggest a labilizing effect of chloroquine …. A similar activation can be induced in the liver by glucagon treatment in vivo [l] or by amino acid. Levigate with a small amount of glycerin or distilled water. Jul 17, 2019 · Chloroquine is a lysosomal lumen alkalizer and a lysosomal autophagy inhibitor that impairs lysosomal functions. Chloroquine is. Chloroquine is a member of quinolone family and is a weak intercalating agent. As a result, cells are not able chloroquine lysosomal acidification to proceed with endocytosis, exosome release and phagolysosomal fusion in an orderly manner. D.-M. This accumulation leads to inhibition of lysosomal enzymes that require an acidic pH, and prevents fusion of endosomes and lysosomes 4. Chloroquine is a lysosomotropic agent that prevents endosomal acidification 1. CHQ has, however, since accrued a plethora of uses in the treatment and amelioration of several other diseases and conditions because of ...
Lysosomes and lysosomal enzymes play a central part in numerous cellular processes, including cellular nourishment, recycling, signaling, defense, and cell death. demonstrated by electron microscopy, with Rabbit polyclonal to STAT6.STAT6 transcription factor of the STAT family.Plays a central role in IL4-mediated biological responses.Induces the expression of BCL2L1/BCL-X(L), which is responsible for the anti-apoptotic activity of IL4. an electron dense appearance and membranous whorls [1, 7, 8]. Lysosomes consist of a phospholipid bilayer membrane enclosing a lumen wherein the pH is definitely managed at 4.5C5.0 to facilitate the action of acid hydrolases (Number 1A) [9, 10]. In addition, the lysosomal membranes consist of integral proteins that are greatly glycosylated to prevent their personal degradation by the hydrolytic enzymes in the lumen. The major proteins, lysosome-associated membrane proteins LAMP-1, LAMP-2, LAMP-3 or tetraspanin CD63, and lysosome integral membrane protein LIMP-2, ...
Two murine lysosome-associated membrane proteins, LAMP-1 of 105,000-115,000 D and LAMP-2 of 100,000-110,000 D, have been identified by monoclonal antibodies that bind specifically to lysosomal membranes. Both glycoproteins were distinguished as integral membrane components solubilized by detergent solutions but not by various chaotropic agents. The lysosome localization was demonstrated by indirect immunofluorescent staining, co-localization of the antigen to sites of acridine orange uptake, and immunoelectron microscopy. Antibody binding was predominantly located at the limiting lysosomal membrane, distinctly separated from colloidal gold-labeled alpha-2-macroglobulin accumulated in the lumen during prolonged incubation. LAMP-1 and LAMP-2 also appeared to be present in low concentrations on Golgi trans-elements but were not detected in receptosomes marked by the presence of newly endocytosed alpha-2-macroglobulin, or in other cellular structures. LAMP-1 and LAMP-2 were distinguished as ...
Background Mutations in αB-crystallin result in proteotoxic cardiomyopathy with desmin mislocalization to protein aggregates. Intermittent fasting ( IF ) is a novel approach to activate transcription factor EB (TFEB), a master regulator of the autophagy-lysosomal pathway, in the myocardium. We teste …
Pharmacological challenges to oncogenic Ras-expressing cancer cells have shown a novel type of cell death, ferroptosis, which requires intracellular iron. In the present study, we assessed ferroptosis following treatment of human fibrosarcoma HT1080 cells with several inhibitors of lysosomal activity and found that they prevented cell death induced by the ferroptosis-inducing compounds erastin and RSL3. Fluorescent analyses with a reactive oxygen species (ROS) sensor revealed constitutive generation of ROS in lysosomes, and treatment with lysosome inhibitors decreased both lysosomal ROS and a ferroptotic cell-death-associated ROS burst. These inhibitors partially prevented intracellular iron provision by attenuating intracellular transport of transferrin or autophagic degradation of ferritin. Furthermore, analyses with a fluorescent sensor that detects oxidative changes in cell membranes revealed that formation of lipid ROS in perinuclear compartments probably represented an early event in ...
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Abstract: Effects of single and repeated injections of lysosomotropic agent chloroquine on lysosomal proteolytic activity and physico-chemical properties of rat liver lysosomes have been studied. Chloroquine was administered intraperitoneally to rats at a dose of 30 mg/kg of body mass. Osmotic properties, lysosomal enzymes activity and functional state of the system of mononuclear phagocytes were estimated. No alterations of colloid carbon clearance followed by a single dose of chloroquine administration were noted. Distinct alterations in osmotic properties, weak labilization of lysosomes and an increase in acid hydrolases activity were similar after single and/or repeated chloroquine administrations, whereas activation of cysteine proteinases and cathepsin D were most pronounced. Chloroquine accumulation by rat liver cells proved to be similar, but the drug excretion was longer after repeated injections. The lysosomal disorders noted were similar to those symptoms of lysosomal storage disease ...
Cellular organelles enable the spatial clustering of molecules, thus favoring their interactions in microenvironments ideally suited for specific complex functions. A well‐known function of the lysosome is to degrade and recycle cellular waste. Extracellular materials reach the lysosome mainly through endocytosis and phagocytosis, while a completely different process, autophagy, mediates the delivery of intracellular materials. Autophagy is activated by a broad range of cellular stress‐inducing conditions and mediates the degradation of protein aggregates, oxidized lipids, damaged organelles, and intracellular pathogens. The process typically involves the formation of double membrane‐bound vesicles, the autophagosomes, which sequester cytoplasmic material and then fuse with lysosomes. Materials that reach the lysosome are degraded by lysosomal hydrolases, and the resulting breakdown products are used to generate new cellular components and energy in response to the nutritional needs of the ...
The cDNA sequence of mouse LAMP 2: evidence for two classes of lysosomal membrane glycoproteins is an eagle-i resource of type Journal article at eagle-i Network Shared Resource Repository.
TY - JOUR. T1 - The kinetics of phagosome maturation as a function of phagosome/lysosome fusion and acquisition of hydrolytic activity. AU - Yates, Robin M.. AU - Hermetter, Albin. AU - Russell, David G.. PY - 2005. Y1 - 2005. U2 - 10.1111/j.1600-0854.2005.00284.x. DO - 10.1111/j.1600-0854.2005.00284.x. M3 - Article. VL - 6. SP - 413. EP - 420. JO - Traffic. JF - Traffic. SN - 1398-9219. IS - 5. ER - ...
A lysosome is a cell organelle.[1] They are like spheres. They have hydrolytic enzymes which can break down almost all kinds of biomolecules, including proteins, nucleic acids, carbohydrates, lipids, and cellular debris. They contain more than 50 different enzymes. By convention, lysosome is the term used for animal cells.[2] In plant cells, vacuoles do similar functions. With a wider definition, lysosomes are found in the cytoplasm of plant and protists as well as animal cell. Lysosomes work like the digestive system to break down, or digest, proteins, acids, carbohydrates, dead organelles, and other unwanted materials.[3] They break up larger molecules into smaller molecules. Those smaller molecules can then be used again as building blocks for other large molecules.[3] ...
Lysosomes are membrane-delimited organelles in animal cells serving as the cells main digestive compartment to which all sorts of macromolecules are delivered for degradation. They contain more than 40 hydrolases in an acidic environment (pH of about 5). After synthesis in the ER, lysosomal enzymes are decorated with mannose-6-phosphate residues, which are recognized by mannose-6-phosphate receptors in the trans-Golgi network. They are packaged into clathrin-coated vesicles and are transported to late endosomes. Substances for digestion are acquired by the lysosomes via a series of processes including endocytosis, phagocytosis, and autophagy ...
Niemann-Picks disease type C1 is a rare, inheritable and currently untreatable lysosomal storage disease. The main characteristic of this disease is accumulation of cholesterol in the endo-lysosomal system. The cause of the disease is a mutation in the NPC1 protein, which is necessary for egress of cholesterol from lysosomes. The disease is severe and progressive and includes neurological symptoms such as ataxia, dysphagia and dementia. In most cases, (hepato)splenomegaly is also present. Besides, Niemann-Picks disease type C is simmilar to Alzheimers disease. Neurofibrillary tangles and amyloidogenic processing of APP are present in both of these conditions. An effort was made to see this disease in a new light by investigating the N-glycans of lysosomal membrane glycoproteins. CHO-NPC1 -/- cell culture was used for this purpose, as well as CHOwt cells as a control group. In order to isolate the lysosomal membrane glycoproteins, magnetic chromatography and Triton x-114 mediated phase ...
Autophagy (Autofagia) Mohamed Elgendy MD, PhD Autophagy (Autofagia) Mohamed Elgendy MD, PhD [email protected] Auto+phagy Greek for Self Eating Autophagy = Recycling Types of Autophagy • 1-Macro-autophagy • 2-Micro-autophagy • 3-Chaperon-mediated autophagy Macro-autophagy 1-Induction Lysosome Autophagosome Fusion LC 3 LC3 II PE LC 3 LC 3 Phagophore 2-Nucleation Autolysosome LC3 I 3-Maturation Other types of Autophagy • Macro-autophagy Delivery of cytoplasmic cargo to the lysosome through the intermediary of a double membranebound vesicle, referred to as an autophagosome, that fuses with the lysosome to form an autolysosome. • Micro-autophagy Cytosolic components are directly taken up by the lysosome itself through invagination of the lysosomal membrane • Chaperon-mediated autophagy Targeted proteins are translocated across the lysosomal membrane in a complex with chaperone proteins (such as Hsc-70) that are recognized by the lysosomal membrane receptor LAMP-2A, resulting in their ...
EMBO Workshop: Lysosomes and metabolism (http://meetings.embo.org/event/18-lysosomes) For many years, the lysosome or vacuole represented the cells waste-yard, where cargo delivered through autophagy pathways and from the late endosome is digested or recycled. However, compelling recent evidence suggests that the lysosome harbors a complex nutrient sensing machinery that regulates important cellular processes including autophagy, lysosomal biogenesis, … Continue reading EMBO Workshop: Lysosomes and Metabolism. ...
We tested the hypothesis that TAG accumulation in the liver induced by short-term high-fat diet (HFD) in rats leads to the dysregulation of endogenous TAG degradation by lysosomal lipase (LIPA) via lysosomal pathway and is causally linked with the onset of hepatic insulin resistance. We found that LIPA could be translocated between qualitatively different depots (light and dense lysosomes). In contrast to dense lysosomal fraction, LIPA associated with light lysosomes exhibits high activity on both intracellular TAG and exogenous substrate and prandial- or diet-dependent regulation. On standard diet, LIPA activity was upregulated in fasted and downregulated in fed animals. In the HFD group, we demonstrated an increased TAG content, elevated LIPA activity, enhanced production of diacylglycerol, and the abolishment of prandial-dependent LIPA regulation in light lysosomal fraction. The impairment of insulin signalling and increased activation of PKC|i|ε|/i| was found in liver of HFD-fed animals. Lipolysis
Lysosomal Lipid Binding and Transfer Proteins. Sphingolipid Metabolism, Intervesicular Lipid Transfer and Vesicle Fusion Fig. 1: Proposed topology of endocytosis and lysosomal degradation.
Autophagy is considered primarily a cell survival process, although it can also lead to cell death. However, the factors that dictate the shift between these 2 opposite outcomes remain largely unknown. In this work, we used D9 -tetrahydrocannabinol (THC, the main active component of marijuana, a compound that triggers autophagy-mediated cancer cell death) and nutrient deprivation (an autophagic stimulus that triggers cytoprotective autophagy) to investigate the precise molecular mechanisms responsible for the activation of cytotoxic autophagy in cancer cells. By using a wide array of experimental approaches we show that THC (but not nutrient deprivation) increases the dihydroceramide:ceramide ratio in the endoplasmic reticulum of glioma cells, and this alteration is directed to autophagosomes and autolysosomes to promote lysosomal membrane permeabilization, cathepsin release and the subsequent activation of apoptotic cell death. These findings pave the way to clarify the regulatory mechanisms ...
antibody-antibodies.com is the marketplace for research antibodies. Find the right antibody for your research needs. Lysosomal Ca2+ Signaling Regulates High Glucose-Mediated Interleukin-1β Secretion via Transcription Factor EB in Human Monocytic Cells.
We study the retinal pigment epithelium (RPE), which nourishes and supports the light-sensingphotoreceptors in the retina. The RPE is also the initial site of damage in macular degenerations. How RPE injury leads to vision loss is not yet clear. We use cutting-edge live imaging of healthy and diseased retina along with animal models and advanced cellular and molecular assays to identify early insults that compromise RPE function and can eventually lead to AMD. To gain insight into disease pathogenesis, our research team investigates mechanisms that regulate critical pathways such as autophagy and lysosome function, mitochondrial dynamics, complement-mediated inflammation, and RPE-photoreceptor communication.. ...
Mouse beta-glucuronidase has a dual intracellular localization, being present in both endoplasmic reticulum and lysosomes of several tissues. Previous studies demonstrated that the protein egasyn is complexed with microsomal but not lysosomal glucuronidase and that a mutant lacking egasyn is deficient in microsomal, but not lysosomal, glucuronidase. By means of a recently developed radioimmunoassay for egasyn, the relationship between microsomal glucuronidase levels and egasyn levels has been examined in various adult tissues, during postnatal development in liver, and after androgen induction of glucuronidase in kidney. The results indicate that the relative availability of egasyn determines the balance between glucuronidase incorporation into membranes and that into lysosomes.
Body proteins in cats were prelabelled with [14C]valine, and protein degradation was studied in isolated hepatocytes. Amino acids appeared to have a direct inhibitory effect on protein degradation, but the effects were generally smaller than those previously shown in the rat. The amino acid control of protein degradation in the cat differs from that in the rat, as shown by the lack of effects of glutamine, asparagine, arginine or methionine in cat hepatocytes. This may be related to the unique features of protein metabolism of this species. NH4Cl, leupeptin and amino acids, which suppress lysosomal protein degradation by different mechanisms, caused less than 30% inhibition of protein degradation when used at the optimum concentrations reported for the rat. The ability of the lysosomal system to respond to nutritional deprivation is apparently lower in the cat than in the rat.. ...
FUNCTION: [Summary is not available for the mouse gene. This summary is for the human ortholog.] This gene encodes the beta subunit of lysosomal acid phosphatase (LAP). LAP is chemically and genetically distinct from red cell acid phosphatase. The encoded protein belongs to a family of distinct isoenzymes which hydrolyze orthophosphoric monoesters to alcohol and phosphate. LAP-deficiencies in mice cause multiple defects including bone structure alterations, lysosomal storage defects in the kidneys and central nervous system, and an increased tendency towards seizures. An enzymatically-inactive allele of LAP in mice exhibited a more severe phenotype than the null allele, and defects included cerebellum abnormalities, growth retardation, hair-follicle abnormalities, and an ataxia-like phenotype. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Oct 2014 ...
Lysosomes are cells recycling and waste disposal system. It contains a battery of enzymes (acid hydrolases) that degrade a wide variety of macromolecules and cellular debris into reusable forms. In so doing lysosomes play a vital role in maintaining cellular homeostasis. The broad goal of our research is to understand the role of this fascinating organelle in human health and diseases. We use various methods ranging from molecular biology, cell biology, protein biochemistry to genomic and proteomic tools to address our research problems. Current research in our laboratory is focused on two major areas: 1. To investigate the pathogenesis of mucopolysaccharidoses, a group of genetic disorders caused by deficiency of one of the eleven lysosomal enzymes required for stepwise degradation of glycosaminoglycans (GAGs). Widespread lysosomal accumulation of undegraded or partially degraded GAGs results in cellular and multiple organ dysfunctions leading to premature death in most cases. The genetic ...
Key Difference - Lysosome vs Vacuole Lysosome is a membrane bound organelle designed for the functions of digestion and phagocytosis. Vacuole is another
Two closely related human Arls, Arl8a and Arl8b, were found to localise to lysosomes in mammalian cells. conventionally, membrane binding of Arf and Arl proteins is mediated by both an N-terminal myristoyl group and an N-terminal amphipathic helix that are inserted into the lipid bilayer upon activation of the GTPase. Arl8 GPTases lack myristolylation sites, and examination of the N-terminus of Arl8b revealed that it contains an acetyl group instead, and this acetylated methionine is necessary for its lysosomal location. Lysosomes of cells overexpressing Arl8b move more frequently, suggesting a role for Arl8a and Arl8b as positive regulators of lysosomal transport. Arl4a, Arl4c and Arl4d are very similar in sequence and were found to act in a pathway upstream of Arf6, Arf6 is a regulator of key processes at the plasma membrane, such as endocytosis, actin dynamics and cell adhesion. One of the major activators of Arf6 is the exchange factor ARNO (Arf nucleotide binding site opener). In order to ...
NPC2, a secreted protein containing a lipid recognition domain, may function in regulating the transport of cholesterol through the late endosomal/lysosomal system. NPC2 may be involved in the regulation of the lipid composition of sperm membranes during the maturation in the epididymis. Mutations in this gene have been associated with Niemann-Pick disease, type C2 and frontal lobe atrophy.
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The macrophage-stimulating effect of Turkey Tail mushroom extracted from Coriolus versicolor (Turkey Tail mushroom) was investigated, and their effectiveness was compared with that of lipopolysaccharide (LPS). The purified polysaccharide (CV-S2-Fr.I) of C. versicolor obtained by Sepharose CL-6B gel chromatography stimulated macrophage lysosomal enzyme activity by 250% at a concentration of 100 microg/mL, which was higher than that of LPS at the same concentration. When CV-S2-Fr.I was used in combination with interferon-gamma, there was a marked cooperative induction of nitric oxide production. However, CV-S2-Fr.I had no effect on nitric oxide production by itself. The proportion of C3-positive macrophages in the CV-S2-Fr.I group increased by 7.2-fold compared with the control group.. ...
In order to further investigate and compare the degree of co-localization of DOX to different subcellular compartments, several parameters were calculated including Pearsons coefficient (P), the overlap coefficient (O), and Manders coefficients M1 and M2.72 M1 reflects the portion of cellular components that co-localize with DOX, and M2 indicates the portion of DOX co-localized with cellular components. All of these coefficients were converted into a heat map (Fig. 5B) in which high values of P, O, and M1 are considered to be indicative of high co-localization while M2 is not. According to the heat map, high values of P, O, and M1 were found in the nuclei, lysosomes, and mitochondria indicating high levels of DOX distribution to these compartments. Lysosomes had the highest degree of co-localization to DOX, which was expected because lysosomes can entrap most exogenous substances, including drugs and smaller nanocarriers.24,25 It is commonly assumed that histidine/histamine functional NPs44,45 ...
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For other Linux-based storre or web servers, youll have to adjust accordingly. To evaluate lysosomal morphology, cells were stained with 500 nm Lysotracker Red (Invitrogen) for 30 min. Esrver addressing bboot VPS plans. S4 ). 2 NP-40), and lysed by lysozyme treatment (1. There are no specific FAQs related to this product. Configuratio, make it executable by running chmod x Now, you can run restart windows server 2008 boot configuration data store to restart your server. Remember - if you maintain a copy, your JohnCompanies filesystem is your backup. I have also tried A Small Orangeв which gave me a bad experience. The player then conducts attacks against the other players PSFs. Shown in Windows server 2008 boot configuration data store 3 are median IgG responses to the VSP antigens from children by age ( Figure 3A ) and from the 30 Haitian adults ( Figure 3B ). Sinai West, holding an interest in the medicalsurgical treatment of Allergy, Asthma and Immunology. Not only that, but your website ...
Myotubularins phosphatase domain is a 3-phosphatases specific for membrane-embedded PtdIns3P and PtdIns(3,5)P2, two PIs that function within the endosomal-lysosomal ...
Its clear from the evidence, as well as common sense, that PPIs have a systemic effect on the entire body, not just the small function they are prescribed to adjust. PPIs launch an attack on basic cellular functioning, inhibiting healthy cell metabolism from taking place. When the bodys ability to convert the building blocks of life, namely proteins, carbohydrates, fats, and nucleic acids, into useable fuel is compromised, so is our immune system, and life begins shutting down. An older study that helped pioneer awareness of harm due to PPIs, is a 2013 study called Inhibition of lysosomal enzyme activities by proton pump inhibitors. Researchers observed that many of the adverse effects of PPIs are caused by systemically compromised immunity, a result of PPI inhibition of lysosomal enzymes. Lysosomes are essentially tiny membranes or sacs that carry enzymes essential to cellular metabolic functions. When PPIs inhibit this function, there is an increased incidence of tumors (tumorigenesis) and ...
The conserved oligomeric complex (COG) is a multi-subunit vesicle tethering complex that functions in retrograde trafficking at the Golgi. We have previously demonstrated that the formation of enlarged endo-lysosomal structures (EELSs) is one of the major glycosylation-independent phenotypes of cells depleted for individual COG complex subunits. Here, we characterize the EELSs in HEK293T cells using microscopy and biochemical approaches. Our analysis revealed that the EELSs are highly acidic and that vATPase-dependent acidification is essential for the maintenance of this enlarged compartment. The EELSs are accessible to both trans-Golgi enzymes and endocytic cargo. Moreover, the EELSs specifically accumulate endolysosomal proteins Lamp2, CD63, Rab7, Rab9, Rab39, Vamp7, and STX8 on their surface. The EELSs are distinct from lysosomes and do not accumulate active Cathepsin B. Retention using selective hooks (RUSH) experiments revealed that biosynthetic cargo mCherry-Lampl reaches the EELSs much ...
TY - JOUR. T1 - DRAM1 regulates autophagy flux through lysosomes.. AU - ZHANG, X. AU - QI, L. AU - WU, J. AU - QIN, Z. PY - 2013/6/1. Y1 - 2013/6/1. M3 - Article. C2 - 23696801. VL - 8(5): e63245.. JO - PLoS One.. JF - PLoS One.. ER - ...
XenoTech processes donor tissue every day. Our expertise and unique preparation procedures allow us to get the most out of each and every tissue. As a result, we often have surplus inventory of products remaining from our custom preparations, including Hepatocytes, Microsomes, S9, Cytosol, Homogenate, Lysosomes, Mast Cells, Mitochondria & Non-Parenchymal Cells from liver, kidney, intestine, lung, spleen, heart, muscle, eye, gland, brain and other tissue from cat, chicken, cow, dog, gerbil, goat, guinea pig, hamster, horse, human, minipigs, monkeys, mice, pig, rabbits, rats, sheep...
By studying the role of lysosomes in mitosis, an IDIBELL and UB group discovers that alterations in the separation of chromosomes cause a detectable nucleus morphology once mitosis has finished.
The main function of Golgi apparatus is secretion, packaging and modifying of the proteins. It is also involved in the synthesis of new membrane and lysosomes. ...