A fundamental question regarding autophagosome formation is how the shape of the double-membrane autophagosomal vesicle is generated. Here we show that in mammalian cells assembly of an actin scaffold inside the isolation membrane (the autophagosomal precursor) is essential for autophagosomal membrane shaping. Actin filaments are depolymerized shortly after starvation and actin is assembled into a network within the isolation membrane. When formation of actin puncta is disrupted by an actin polymerization inhibitor or by knocking down the actin-capping protein CapZβ, isolation membranes and omegasomes collapse into mixed-membrane bundles. Formation of actin puncta is PtdIns(3)P dependent, and inhibition of PtdIns(3)P formation by treating cells with the PI(3)K inhibitor 3-MA, or by knocking down Beclin-1, abolishes the formation of actin puncta. Binding of CapZ to PtdIns(3)P, which is enriched in omegasomes, stimulates actin polymerization. Our findings illuminate the mechanism underlying

The goal of this project is to unveil how membranes are assembled into autophagosomes. We will uniquely combine yeast Saccharomyces cerevisiae genetics and immuno-electron tomography to reach this objective. At first, we will devise a novel electron tomography protocol to preserve yeast autophagosomal membranes near their native state and be able immunolabel them. Subsequently, we will exploit this procedure to develop a model about how autophagosomal membranes are assembled into autophagosomes by analysing the precursor structures accumulated in yeast autophagy mutants. This unique experimental system will allow us visualizing the formation of autophagosomes through 3-dimentional images with ultrastructural resolution, and determine the distribution of Atg proteins, thus acquitting insights into their function ...

Phagocytosis involves the internalization of extracellular material by invagination of the plasma membrane to form intracellular vesicles called phagosomes, which have functions that include pathogen degradation. The degradative properties of phagosomes are thought to be conferred by sequential fusion with endosomes and lysosomes; however, this maturation process has not been studied in vivo. We employed Drosophila hemocytes, which are similar to mammalian professional macrophages, to establish a model of phagosome maturation. Adult Drosophila females, carrying transgenic Rab7-GFP endosome and Lamp1-GFP lysosome markers, were injected with E. coli DH5α and the hemocytes were collected at 15, 30, 45 and 60 minutes after infection. In wild-type females, E. coli were detected within enlarged Rab7-GFP positive phagosomes at 15 to 45 minutes after infection; and were also observed in enlarged Lamp1-GFP positive phagolysosomes at 45 minutes. Two-photon imaging of hemocytes in vivo confirmed this vesicle

Intestinal epithelial cells (IECs) play a key role in regulating immune responses and controlling infection. However, the direct role of IECs in restricting pathogens remains incompletely understood. Here, we provide evidence that IL-22 primed intestinal organoids derived from healthy human induced pluripotent stem cells (hIPSCs) to restrict Salmonella enterica serovar Typhimurium SL1344 infection. A combination of transcriptomics, bacterial invasion assays, and imaging suggests that IL-22-induced antimicrobial activity is driven by increased phagolysosomal fusion in IL-22-pretreated cells. The antimicrobial phenotype was absent in hIPSCs derived from a patient harboring a homozygous mutation in the IL10RB gene that inactivates the IL-22 receptor but was restored by genetically complementing the IL10RB deficiency. This study highlights a mechanism through which the IL-22 pathway facilitates the human intestinal epithelium to control microbial infection.

Phagosome formation and subsequent maturation are complex sequences of events that involve actin cytoskeleton remodeling and membrane trafficking. Here, we demonstrate that the Ras‐related protein Rab35 is involved in the early stage of FcγR‐mediated phagocytosis in macrophages. Live‐cell image analysis revealed that Rab35 was markedly concentrated at the membrane where IgG‐opsonized erythrocytes (IgG‐Es) are bound. Rab35 silencing by RNA interference (RNAi) or the expression of GDP‐ or GTP‐locked Rab35 mutant drastically reduced the rate of phagocytosis of IgG‐Es. Actin‐mediated pseudopod extension to form phagocytic cups was disturbed by the Rab35 silencing or the expression of GDP‐Rab35, although initial actin assembly at the IgG‐E binding sites was not inhibited. Furthermore, GTP‐Rab35‐dependent recruitment of ACAP2, an ARF6 GTPase‐activating protein, was shown in the phagocytic cup formation. Concomitantly, overexpression of ACAP2 along with GTP‐locked Rab35 ...

Given the diversity of autophagy targets and regulation, it is important to characterize autophagy in various cell types and conditions. We used a primary myocyte cell culture system to assay the role of putative autophagy regulators in the specific context of skeletal muscle. By treating the cultures with rapamycin (Rap) and chloroquine (CQ) we induced an autophagic response, fully suppressible by knockdown of core ATG genes. We screened D. melanogaster orthologs of a previously reported mammalian autophagy protein-protein interaction network, identifying several proteins required for autophagosome formation in muscle cells, including orthologs of the Rab regulators RabGap1 and Rab3Gap1. The screen also highlighted the critical roles of the proteasome and glycogen metabolism in regulating autophagy. Specifically, sustained proteasome inhibition inhibited autophagosome formation both in primary culture and larval skeletal muscle, even though autophagy normally acts to suppress ubiquitin ...

Dengue virus (DENV)[seventeen], hepatitis B virus (HBV) [31] and influenza A virus (IAV)[32] not only have been revealed to induce autophagy but also upregulate autophagy to market virus replication. Curiously, human parainfluenza virus sort 3 (HPIV3)[33], rotavirus and human immunodeficiency virus sort 1(HIV-one)[34] have been reported to induce autophagy but to block the fusion in between autophagosomes and lysosomes, leading to autophagosome accumulation to 859212-16-1 supplier facilitate viral generation. In this study, we found that CA16 an infection could induce autophagy. Nevertheless, the autophagosomes unsuccessful to fuse with the lysosomes, major to considerable autophagosome accumulation. The offered data indicate that the gathered autophagosomes could in change favor the reproduction of RNA viruses by many mechanisms. Initial, autophagosomes that are unsuccessful to fuse with lysosomes might stop the freshly fashioned virions or viral RNA from degrading or currently being processed ...

The interest on autophagy, an evolutionarily conserved process in eukaryotes, has enormously increased in the last years, since the malfunctioning of autophagy is involved in many diseases such as cancer or neurodegenerative states. Autophagosome formation is the key process in autophagy. Despite extensive work, the model of autophagosome formation is not yet fully established. Some important questions remain to be elusive, such as where the bona fide marker protein of autophagosome, LC3, is lipidated, how lipidated LC3 functions in autophagosome formation, and how the proteins for LC3 lipidation and delipidation are involved in autophagosome formation.. Although genetic approaches have been powerful to dissect autophagosome formation process, intrinsic limitations include the lack of acute manipulation in protein activity. We will prepare semi-synthetic LC3 and lipidated LC3 proteins and use them to monitor dynamics of autophagosome formation in vitro and in cells. The semi-synthetic LC3 ...

Salmonella species are facultative intracellular pathogens. Following entry into mammalian host cells, they reside in membrane-bound vacuoles, resist killing, and replicate. In this work, we investigated the importance of phagosomal pH in the ability of Salmonella typhimurium to survive and replicate within macrophages. Intraphagosomal pH was measured in situ by recording the fluorescence intensity of a pH-sensitive probe, DM-NERF dextran. The majority of vacuoles containing S. typhimurium (live, heat killed, or formalin fixed) acidified from pH , or = 6.0 to between pH 4.0 and 5.0 within 60 min after formation. In contrast, Mycobacterium avium-containing vacuoles failed to acidify even at later time points. Acidification of S. typhimurium-containing vacuoles was completely blocked by treatment of host cells with bafilomycin A, a specific inhibitor of vacuolar proton-ATPases. Bafilomycin inhibition of vacuolar acidification from the onset of infection significantly decreased the survival of S. ...

Autophagosomes are double-membrane vesicles characteristic of macroautophagy, a degradative pathway for cytoplasmic material and organelles terminating in the lysosomal or vacuole compartment for mammals and yeast, respectively. This highly dynamic, multi-step process requires significant membrane reorganization events at different stages of the macroautophagic process. Such events include exchange and flow of lipids and proteins between membranes and vesicles (e.g., during initiation and growth of the phagophore), vesicular positioning and trafficking within the cell (e.g., autophagosome location and movement) and fusion of autophagosomes with the boundary membranes of the degradative compartment. Here, we review current knowledge on the contribution of different organelles to the formation of autophagosomes, their trafficking and fate within the cell. We will consider some of the unresolved questions related to the molecular mechanisms that regulate the

Invasive infections by the human pathogenic fungus Aspergillus fumigatus start with the outgrowth of asexual, airborne spores (conidia) into the lung tissue of immunocompromised patients. The resident alveolar macrophages phagocytose conidia, which end up in phagolysosomes. However, A. fumigatus conidia resist phagocytic degradation to a certain degree. This is mainly attributable to the pigment 1,8-dihydroxynaphthalene (DHN) melanin located in the cell wall of conidia, which manipulates the phagolysosomal maturation and prevents their intracellular killing. To get insight in the underlying molecular mechanisms, we comparatively analyzed proteins of mouse macrophage phagolysosomes containing melanized wild-type (wt) or non-melanized pksP mutant conidia. For this purpose, a protocol to isolate conidia-containing phagolysosomes was established and a reference protein map of phagolysosomes was generated. We identified 637 host and 22 A. fumigatus proteins that were differentially abundant in the ...

The GTPase Ypt1 and its mammalian homolog Rab1 regulate three different trafficking events: autophagy, ER-Golgi, and intra-Golgi traffic (12). During autophagy, Ypt1 is recruited to the phagophore by the TRAPPIII complex, one of three multimeric Ypt1/Rab1 GEFs that localize to distinct cellular locations (12). These complexes share several essential subunits that are required for GEF activity. The TRAPPIII-specific subunit Trs85 specifically directs TRAPPIII to the phagophore where it recruits and activates Ypt1 on the autophagy pathway (14).. To determine where on the autophagy pathway TRAPPIII and Ypt1 act, we screened all known autophagy-deficient atg mutants for defects in the recruitment of Trs85 to the PAS. This screen revealed that the recruitment of TRAPPIII to the PAS is dependent on Atg17 and suggested that Ypt1 and its GEF act in the induction step of the pathway. Five Atg proteins act in induction: Atg1, Atg13, Atg17, Atg29, and Atg31 (6, 9). Of these, only Atg1 is recruited to the ...

Analyses of a developmentally regulated Drosophila myofiber remodeling program provide insight into induced autophagy required for T-tubule membrane reorganization, and uncover a conserved Rab2 role in autophagosome-lysosome fusion.

Cells undergo autophagy or self-eating as a means of recycling their constituents in order to maintain homeostasis. Autophagy is up regulated by stress, including amino acid deprivation for which it is best characterised. Upon amino acid starvation double or multiple lamellar vesicles termed autophagic vacuoles (AV) or autophagosomes appear throughout the cells cytoplasm. From their content they can be seen to have sequestered cytoplasm, often including organelles. Screens for autophagy defective mutants in Saccharomyces cerevisiae resulted in the AuTophaGy (ATG) genes. I have studied the ubiquitously expressed mammalian orthologue of Atg9p (Atg9Ll), a multi-spanning transmembrane protein shown to be essential in yeast for autophagy. I studied Atg9Ll in the hope that, as it is a multi-spanning transmembrane protein, it might provide clues as to the origin of the autophagosomal membranes. Initially addressing the proteins topology I show that both the N-and C-termini of Atg9L1 are cytosolic, ...

Macroautophagy, a major pathway for organelle and protein turnover, has been implicated in the neurodegeneration of Alzheimers disease (AD). The basis for the profuse accumulation of autophagic vacuoles (AVs) in affected neurons of the AD brain, however, is unknown. In this study, we show that constitutive macroautophagy in primary cortical neurons is highly efficient, because newly formed autophagosomes are rapidly cleared by fusion with lysosomes, accounting for their scarcity in the healthy brain. Even after macroautophagy is strongly induced by suppressing mTOR (mammalian target of rapamycin) kinase activity with rapamycin or nutrient deprivation, active cathepsin-positive autolysosomes rather than LC3-II-positive autophagosomes predominate, implying efficient autophagosome clearance in healthy neurons. In contrast, selectively impeding late steps in macroautophagy by inhibiting cathepsin-mediated proteolysis within autolysosomes with cysteine- and aspartyl-protease inhibitors caused a marked

Sorting of luminal and membrane proteins into phagosomes is critical for the immune function of this organelle. However, little is known about the mechanisms that contribute to the spatiotemporal regulation of this process. Here, we investigated the role of the proneurotrophin receptor sortilin during phagosome maturation and mycobacterial killing. We show that this receptor is acquired by mycobacteria-containing phagosomes via interactions with the adaptor proteins AP-1 and GGAs. Interestingly, the phagosomal association of sortilin is critical for the delivery of acid sphingomyelinase (ASMase) and required for efficient phagosome maturation. Macrophages from Sort1(-/-) mice are less efficient in restricting the growth of Mycobacterium bovis BCG and M. tuberculosis. In vivo, Sort1(-/-) mice showed a substantial increase in cellular infiltration of neutrophils in their lungs and higher bacterial burden after infection with M. tuberculosis. Altogether, sortilin defines a pathway required for ...

Candida glabrata currently ranks as the second most frequent cause of invasive candidiasis. Our previous work has shown that C. glabrata is adapted to intracellular survival in macrophages and replicates within non-acidified late endosomal-stage phagosomes. In contrast, heat killed yeasts are found in acidified matured phagosomes. In the present study, we aimed at elucidating the processes leading to inhibition of phagosome acidification and maturation. We show that phagosomes containing viable C. glabrata cells do not fuse with pre-labeled lysosomes and possess low phagosomal hydrolase activity. Inhibition of acidification occurs independent of macrophage type (human/murine), differentiation (M1-/M2-type) or activation status (vitamin D3 stimulation). We observed no differential activation of macrophage MAPK or NFκB signaling cascades downstream of pattern recognition receptors after internalization of viable compared to heat killed yeasts, but Syk activation decayed faster in macrophages ...

Autophagy is a catabolic process that results in the degradation of bulk cytoplasmic contents within autophagosomes and lysosomes. Two human Atg2 homologs (Atg2A, Atg2B) are critical for autophagosome formation as silencing of both results in the accumulation of unclosed autophagic structures. Starvation-induced autophagy targets Atg2A to the initiation site of autophagosome biogenesis, where it associates with DFCP1, WIPI-1, and other autophagy- related proteins. Atg2 proteins also function in lipid droplet metabolism as depletion of both Atg2A and AtgB results in changes in the size, number, and distribution of lipid droplets. An increase in Atg2A expression during etoposide- and doxorubicin-induced apoptosis suggests that Atg2A may be a useful indicator of topoisomerase II inhibitor-mediated apoptosis.. ...

Autophagy is a well-conserved catabolic process essential for cellular homeostasis. First described in yeast as an adaptive response to starvation, this pathway is also present in higher eukaryotes, where it is triggered by stress signals such as damaged organelles or pathogen infection. Autophagy is characterized at the cellular level by the engulfment of portions of the cytoplasm in double-membrane structures called autophagosomes. Autophagosomes fuse with lysosomes, resulting in degradation of the inner autophagosomal membrane and luminal content. This process is coordinated by complex molecular systems, including the ATG8 ubiquitin-like conjugation system and the ATG4 cysteine proteases, which are implicated in the formation, elongation, and fusion of these autophagic vesicles. In this Review, we focus on the diverse functional roles of the autophagins, a protease family formed by the four mammalian orthologs of yeast Atg4. We also address the dysfunctional expression of these proteases in ...

Autophagy is an evolutionary conserved eukaryotic bulk degradation pathway that results in regulated cellular clearance and secures cellular survival. Autophagic dysfunction has been found to be associated with various human diseases including cancer and neurodegeneration. Aiming to develop therapeutics capable to cure age-related human diseases, the molecular details of autophagy are now becoming understood.. We identified the human WIPI gene family (WIPI-1, -2, -3, and -4) and have begun to establish that WIPI genes are aberrantly expressed in a variety of human cancers (Proikas-Cezanne et al., Oncogene 2004). Using biochemical techniques coupled with confocal and electron microscopy we have demonstrated that WIPI-1 (Atg18 in S. cerevisiae) specifically binds PI(3)P at the onset of autophagy and is essential for autophagosome formation. Upon binding to PI(3)P, WIPI-1 protein accumulation at autophagosomal membranes (WIPI-1 puncta-formation) can be visualized by fluorescent microscopy, ...

In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be

Regulator of mitophagy through the upstream regulation of the RNF41/NRDP1-PRKN pathway. Mitophagy is a selective form of autophagy necessary for mitochondrial quality control. The RNF41/NRDP1-PRKN pathway regulates autophagosome-lysosome fusion during late mitophagy. May protect RNF41/NRDP1 from proteosomal degradation, RNF41/NRDP1 which regulates proteosomal degradation of PRKN. Plays a key role in beta cells functions by regulating mitophagy/autophagy and mitochondrial health.

Strains of Escherichia coli persist within the human gut as normal commensals, but are frequent pathogens and can cause recurrent infection. Here we show that, in contrast to E. coli subjected to opsonic interactions stimulated by the hosts immune response, E. coli that bind to the macrophage surface exclusively through the bacterial lectin FimH can survive inside the cell following phagocytosis. This viability is largely due to the attenuation of intracellular free-radical release and of phagosome acidification during FimH-mediated internalization, both of which are triggered by antibody-mediated internalization. This different processing of non-opsonized bacteria is supported by morphological evidence of tight-fitting phagosomes compared with looser, antibody-mediated phagosomes. We propose that non-opsonized FimH-expressing E. coli co-opt internalization of lipid-rich microdomains following binding to the FimH receptor, the glycosylphosphatidylinositol-linked protein CD48, because (1) the sterol

In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be ...

In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be ...

Intracellular parasites of the genus Leishmania generate severe diseases in humans, which are associated with a failure of the infected host to induce a

Bacterial and parasitic intracellular pathogens or their secreted products have been shown to induce host cell transcriptional responses, which may benefit the host, favour the microorganism or be unrelated to the infection. In most instances, however, it is not known if the host cell nucleus is proximately required for the development of an intracellular infection. This information can be obtained by the infection of artificially enucleated host cells (cytoplasts). This model, although rather extensively used in studies of viral infection, has only been applied to few bacterial pathogens, which do not include Mycobacterium spp. Here, we investigate the internalization, phagosome biogenesis and survival of M. smegmatis in enucleated type II alveolar epithelial cells. Cytoplasts were infected with M. smegmatis, but the percentage of infection was significantly lower than that of nucleated cells. Scanning electron microscopy indicated that in both cells and cytoplasts, bacteria were internalized ...

Ubiquitin-like modifier involved in formation of autophagosomal vacuoles (autophagosomes). Plays a role in mitophagy which contributes to regulate mitochondrial quantity and quality by eliminating the mitochondria to a basal level to fulfill cellular energy requirements and preventing excess ROS production. Whereas LC3s are involved in elongation of the phagophore membrane, the GABARAP/GATE-16 subfamily is essential for a later stage in autophagosome maturation. Promotes primary ciliogenesis by removing OFD1 from centriolar satellites via the autophagic pathway ...

Autophagy is a cellular process mediating degradation of bulk cytoplasm, long-lived proteins and entire organelles. In this process, double-membrane vesicles, the autophagosomes, wrap around portions of cytosol and transport them to the lysosome for degradation. Several molecules participate in autophagosome nucleation and elongation, including various components of the class III PI3K complex, such as Beclin 1 and Ambra1 (. Activating Molecule in Beclin 1-Regulated Autophagy), which has been recently characterized in our laboratory (1, 2). Any genetic or pharmacological alteration in this process impairs the cell survival rate or cell metabolism, thereby affecting tissue homeostasis (3). Many neurodegenerative conditions, for example, can be traced back to defective autophagy and autophagy has also been identified as a crucial process in oncogenesis and cancer progression. Several autophagy-related proteins have tumor suppressor activity (Beclin 1, Atg5, Bif-1, Atg4C, UVRAG) and some autophagy ...

The fusion of lysosomes to phagosomes was observed under high voltage electron microscopy, in 4μm thick rat retinal sections with the aid of acid phosphatase cytochemistry. The study of thick sections facilitates the observation of the moment of fusion in stereo view from two tilted pictures. From this study, the contents of the lysosome pored into the phagosome through the orifice, shortly after the collision of the two organelles. The hydrolytic enzymes such as acid phosphatase spread in a sheet under the limiting membrane of the phagosome to finally form a balloon of the reaction product. In some case the ballooning appeared to be doubled. The outer skin of the reaction product may be the result of a wrapping mechanism of phagolysosomes.. ...

Macroautophagy - This is widely considered to be the most used pathway of autophagy in the body. It deals with the recycling of dysfunctional organelles and proteins which may have been damaged or incorrectly folded during their synthesis. The process starts with a piece of cellular machinery termed the isolation membrane or phagophore. This is a double membrane structure that elongates and encloses part of the cytoplasm, as well as the target organelles or proteins. The resulting specialised vesicle is termed an autophagosome. The autophagosome then migrates to a lysosome to which it fuses via the outer membrane. It is important to note the outer membrane stays intact thus keeping the contents and Hydrolases within the autolysosome for recycling[8][9]. Microautophagy - This process differs from macroautophagy as it is only concerned with the degradation and recycling of cytoplasm in the cell. It also uses a different mechanism. No autophagosome is formed as the lysosome itself directly ...

Macroautophagy - widely considered to be the most used pathway of autophagy in the body. It deals with the recycling of dysfunctional organelles and proteins which may have been damaged or incorrectly folded during their synthesis. The process starts with a piece of cellular machinery termed the isolation membrane or phagophore which is a double membrane structure that elongates and encloses part of the cytoplasm as well as the target organelles or proteins. This structure is termed an autophagosome. The autophagosome then migrates to a lysosome to which it fuses with via the outer membrane. It is important to note the outer membrane stays intact thus keeping the contents and hydrolyses within the autolysosome for recycling[7][8]. Microautophagy - This differs from macroautophagy as it is only concerned with the degradation and recycling of cytoplasm. It also differs in its mechanism. No autophagosome is formed as the lysosome itself directly degrades the cytoplasm by inward invaginations ...

By M. A. Hayat. Understanding the significance and necessity of the function of autophagy in health and wellbeing and ailment is key for the stories of melanoma, getting older, neurodegeneration, immunology, and infectious illnesses. complete and updated, this publication deals a worthwhile consultant to those mobile approaches when inciting researchers to discover their almost certainly very important connections. Volume 7 presents assurance of the newest advancements in autophagosome biogenesis and rules; the position of autophagy in protein quality controls; and the function of autophagy in apoptosis. awareness is given to autophagy within the cardiovascular method, with specific insights into the function of autophagy in atherosclerosis and the particular habit of autophagy within the sinoatrial node. state of the art findings within the relationships among autophagy and way of life are explored with the law of macroautophagy in keeping with workout, in addition to the promoting of ...

Integral membrane proteins (natural resistance associated macrophage proteins), of the solute carrier family, expressed only in cells of the myeloid series and recruited to the phagosome membrane following phagocytosis. Mutations in Nramp1 (SLC11A1, 550 aa) impair macrophage killing of intracellular parasites such as Mycobacteria, Salmonella, and Leishmania and are also associated with the onset of rheumatoid arthritis. Nramp2 (SLC11A2, 568 aa) is very similar to Nramp1 but more widely expressed and is known to be involved in cellular iron absorption at the luminal surface of the duodenum. ...

2014 Project header}} =Phagocytosis= [[File:Leukocyte_phagocytosis_of_yeast.jpg,thumb,right,300px,Phagocytosis of yeast by a Leukocyte]] ==Introduction== Phagocytosis is a crucial defence mechanism of the innate immune response which eliminates debris and pathogens,ref name=PMID18085665>,pubmed>18085665,/pubmed>,/ref>. Phagocytosis is a specialised type of endocytosis where large (≥0.5 μm),ref name=PMID10358769>,pubmed>10358769,/pubmed>,/ref> solid particles are internalised through the receptor-mediated engulfment of membrane-derived vesicles called phagosomes,ref name=PMID21783028>,pubmed>21783028,/pubmed>,/ref>. After the vesicles detach from the plasma membrane (scission), the phagosome matures by fusing with endosomes and lysosomes (which contain hydrolytic enzymes) to form a phagolysosome. The hydrolytic enzymes in the phagolysosome break down the internalised solid particles. The mechanism behind Phagocytosis is clathrin (a protein that plays a major role in formation of coated ...

Inhibits PIK3C3 activity; under basal conditions negatively regulates PI3K complex II (PI3KC3-C2) function in autophagy. Negatively regulates endosome maturation and degradative endocytic trafficking and impairs autophagosome maturation process. Can sequester UVRAG from association with a class C Vps complex (possibly the HOPS complex) and negatively regulates Rab7 activation (PubMed:20974968, PubMed:21062745).

Tuberculosis, which most often affects the lungs and leads to respiratory impairment, is caused by the acid-fast bacterium, M. tuberculosis. The bacterium is particularly virulent due to its ability to prevent phagosome-lysosome fusion after engulfment by macrophages. Since a phagolysosome is not formed, the bacterium is able to escape degradation. However, when the adaptive immune system is activated, TH1 cells secrete IFN-gamma, which overcomes this bacterial defense mechanism. IFN-gamma also causes macrophages to differentiate into epithelioid cells, which may then combine to create large, multi-nucleated, giant cells (Langhans cells). This eventually leads to the formation of the granuloma that is characteristic of a tuberculosis infection ...

Autophagy is an intracellular bulk degradation system that is found ubiquitously in eukaryotes. Autophagy is responsible for the degradation of most long-lived proteins and some organelles. Cytoplasmic constituents, including organelles, are sequestered into double-membraned autophagosomes, which su …

PubMed comprises more than 30 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.

Wu, Y. (Contributor), Wu, W. (Contributor), Lin, L. (Contributor), Liu, C. (Contributor), Ho, S. (Contributor), Wang, B. (Contributor), Huang, B. (Contributor), Yeh, Y. (Contributor), Chiu, H. (Contributor), Yang, W. (Contributor), Wang, Y. (Contributor) (四月 27 2018). Additional file 3: of Bortezomib enhances radiosensitivity in oral cancer through inducing autophagy-mediated TRAF6 oncoprotein degradation. Unknown Publisher. 10.6084/m9.figshare.6198044.v1 ...

Autophagy is a catabolic process whereby damaged organelles and proteins are sequestered into autophagic vesicles, then degraded through fusion with lysosomes and reused as metabolic precursors. While autophagy can suppress tumorigenesis in normal tissues, stimulation of autophagy in established tumors promotes tumor cell survival under stressful metabolic and environmental conditions and can serve as a mechanism of treatment resistance. Yang and colleagues review the role of autophagy in cancer biology and discuss how autophagy can be exploited as a therapeutic target. While most cancer therapeutics induce autophagy, the functional consequence of autophagy induction in the context of cancer therapy continues to emerge.. ...

Scott RC, et al. (2007) Direct induction of autophagy by Atg1 inhibits cell growth and induces apoptotic cell death. Curr Biol 17(1):1-11 BACKGROUND: To survive starvation and other forms of stress, eukaryotic cells undergo a lysosomal process of cytoplasmic degradation known as autophagy. Autophagy has been implicated in a number of cellular and developmental processes, including cell-growth control and programmed cell death. However, direct evidence of a causal role for autophagy in these processes is lacking, resulting in part from the pleiotropic effects of signaling molecules such as TOR that regulate autophagy. Here, we circumvent this difficulty by directly manipulating autophagy rates in Drosophila through the autophagy-specific protein kinase Atg1. RESULTS: We find that overexpression of Atg1 is sufficient to induce high levels of autophagy, the first such demonstration among wild-type Atg proteins. In contrast to findings in yeast, induction of autophagy by Atg1 is dependent on its ...

Phagocytosis requires receptor-mediated recognition of particles, usually in the guise of infectious agents and apoptotic cells. Phagosomes fuse with lysosomes to generate phagolysosomes, which play a key role in enzymatic digestion of the internaliz

Autophagy (or macroautophagy) is a cellular catabolic pathway involving in protein degradation, organelle turnover, and non-selective breakdown of cytoplasmic components, which is evolutionarily conserved among eukaryotes and exquisitely regulated. This progress initiates with production of the autophagosome, a double-membrane intracellular structure of reticular origin that engulfs cytoplasmic contents and ultimately fuses with lysosomes for cargo degradation. Autophagy is regulated in response to extra- or intracellular stress and signals such as starvation, growth factor deprivation and ER stress. Constitutive level of autophagy plays an important role in cellular homeostasis and maintains quality control of essential cellular components ...

Beclin 2 plays a critical role in metabolic regulation and obesity, but its functions in innate immune signaling and cancer development remain largely unknown. Here, we identified Beclin 2 as a critical negative regulator of inflammation and lymphoma development. Mice with homozygous ablation of BCL2-interacting protein 2 (Becn2) developed splenomegaly and lymphadenopathy and markedly increased ERK1/2 and NF-κB signaling for proinflammatory cytokine production. Beclin 2 targeted the key signaling kinases MEKK3 and TAK1 for degradation through an ATG9A-dependent, but ATG16L/Beclin 1/LC3-independent, autophagic pathway. Mechanistically, Beclin 2 recruited MEKK3 or TAK1 through ATG9A to form a complex (Beclin 2-ATG9A-MEKK3) on ATG9A+ vesicles upon ULK1 activation. Beclin 2 further interacted with STX5 and STX6 to promote the fusion of MEKK3- or TAK1-associated ATG9A+ vesicles to phagophores for subsequent degradation. Importantly, Becn2-deficient mice had a markedly increased incidence of lymphoma ...

Autophagy (Greek, self-eating) is an evolutionarily conserved homeostatic process by which cytoplasmic components are sequestered into double-membraned vesicl...

Autophagy (or macroautophagy) is a cellular catabolic pathway involving in protein degradation, organelle turnover, and non-selective breakdown of cytoplasmic components, which is evolutionarily conserved among eukaryotes and exquisitely regulated. This progress initiates with production of the autophagosome, a double-membrane intracellular structure of reticular origin that engulfs cytoplasmic contents and ultimately fuses with lysosomes for cargo degradation. Autophagy is regulated in response to extra- or intracellular stress and signals such as starvation, growth factor deprivation and ER stress. Constitutive level of autophagy plays an important role in cellular homeostasis and maintains quality control of essential cellular components ...

TY - JOUR. T1 - Xanthohumol impairs autophagosome maturation through direct inhibition of valosin-containing protein. AU - Sasazawa, Yukiko. AU - Kanagaki, Shuhei. AU - Tashiro, Etsu. AU - Nogawa, Toshihiko. AU - Muroi, Makoto. AU - Kondoh, Yasumitsu. AU - Osada, Hiroyuki. AU - Imoto, Masaya. PY - 2012/5/18. Y1 - 2012/5/18. N2 - Autophagy is a bulk, nonspecific protein degradation pathway that is involved in the pathogenesis of cancer and neurodegenerative disease. Here, we observed that xanthohumol (XN), a prenylated chalcone present in hops (Humulus lupulus L.) and beer, modulates autophagy. By using XN-immobilized beads, valosin-containing protein (VCP) was identified as a XN-binding protein. VCP has been reported to be an essential protein for autophagosome maturation. Using an in vitro pull down assay, we showed that XN bound directly to the N domain, which is known to mediate cofactor and substrate binding to VCP. These data indicated that XN inhibited the function of VCP, thereby allowing ...

Background During pancreatitis, autophagy is activated, but lysosomal degradation of dysfunctional organelles including mitochondria is impaired, resulting in acinar cell death. Retrospective cohort analyses demonstrated an association between simvastatin use and decreased acute pancreatitis incidence. Methods We examined whether simvastatin can protect cell death induced by cerulein and the mechanisms involved during acute pancreatitis. Mice were pretreated with DMSO or simvastatin (20 mg/kg) for 24 h followed by 7 hourly cerulein injections and sacrificed 1 h after last injection to harvest blood and tissue for analysis. Results Pancreatic histopathology revealed that simvastatin reduced necrotic cell death, inflammatory cell infiltration and edema. We found that cerulein triggered mitophagy with autophagosome formation in acinar cells. However, autophagosome-lysosome fusion was impaired due to altered levels of LAMP-1, AMPK and ULK-1, resulting in autophagosome accumulation (incomplete ...

Mycobacterium abscessus is a pathogenic, rapidly growing mycobacterium responsible for pulmonary and cutaneous infections in immunocompetent patients and in patients with Mendelian disorders, such as cystic fibrosis (CF). Mycobacterium abscessus is known to transition from a smooth (S) morphotype with cell surface-associated glycopeptidolipids (GPL) to a rough (R) morphotype lacking GPL. Herein, we show that M. abscessus S and R variants are able to grow inside macrophages and are present in morphologically distinct phagosomes. The S forms are found mostly as single bacteria within phagosomes characterized by a tightly apposed phagosomal membrane and the presence of an electron translucent zone (ETZ) surrounding the bacilli. By contrast, infection with the R form leads to phagosomes often containing more than two bacilli, surrounded by a loose phagosomal membrane and lacking the ETZ. In contrast to the R variant, the S variant is capable of restricting intraphagosomal acidification and induces less

Amitriptyline is a tricyclic antidepressant commonly prescribed for major depressive disorders, as well as depressive symptoms associated with various neurological disorders. A possible correlation between the use of tricyclic antidepressants and the occurrence of Parkinsons disease has been reported, but its underlying mechanism remains unknown. The accumulation of misfolded protein aggregates has been suggested to cause cellular toxicity and has been implicated in the common pathogenesis of neurodegenerative diseases. Here, we examined the effect of amitriptyline on protein clearance and its relevant mechanisms in neuronal cells. Amitriptyline exacerbated the accumulation of abnormal aggregates in both in vitro neuronal cells and in vivo mice brain by interfering with the (1) formation of aggresome-like aggregates and (2) autophagy-mediated clearance of aggregates. Amitriptyline upregulated LC3B-II, but LC3B-II levels did not increase further in the presence of NH4Cl, which suggests that

Cellular stress responses often involve elevation of cytosolic calcium levels, and this has been suggested to stimulate autophagy. Here, however, we demonstrated that agents that alter intracellular calcium ion homeostasis and induce ER stress-the calcium ionophore A23187 and the sarco/endoplasmic reticulum Ca (2+)-ATPase inhibitor thapsigargin (TG)-potently inhibit autophagy. This anti-autophagic effect occurred under both nutrient-rich and amino acid starvation conditions, and was reflected by a strong reduction in autophagic degradation of long-lived proteins. Furthermore, we found that the calcium-modulating agents inhibited autophagosome biogenesis at a step after the acquisition of WIPI1, but prior to the closure of the autophagosome. The latter was evident from the virtually complete inability of A23187- or TG-treated cells to sequester cytosolic lactate dehydrogenase. Moreover, we observed a decrease in both the number and size of starvation-induced EGFP-LC3 puncta as well as reduced numbers of

Autophagy-related protein 13 also known as ATG13 is a protein that in humans is encoded by the KIAA0652 gene. ATG13 is an autophagy factor required for phagosome formation. ATG13 is a target of the TOR kinase signaling pathway that regulates autophagy through phosphorylation of ATG13 and ULK1, and the regulation of the ATG13-ULK1-RB1CC1 complex. GRCh38: Ensembl release 89: ENSG00000175224 - Ensembl, May 2017 GRCm38: Ensembl release 89: ENSMUSG00000027244 - Ensembl, May 2017 Human PubMed Reference:. Mouse PubMed Reference:. Entrez Gene: KIAA0652. Mercer CA, Kaliappan A, Dennis PB (July 2009). A novel, human Atg13 binding protein, Atg101, interacts with ULK1 and is essential for macroautophagy. Autophagy. 5 (5): 649-62. doi:10.4161/auto.5.5.8249. PMID 19287211. Hosokawa N, Hara T, Kaizuka T, Kishi C, Takamura A, Miura Y, Iemura S, Natsume T, Takehana K, Yamada N, Guan JL, Oshiro N, Mizushima N (April 2009). Nutrient-dependent mTORC1 Association with the ULK1-Atg13-FIP200 Complex Required ...

Omegasome is a cell compartment consisting of lipid bilayer membranes enriched for phosphatidylinositol 3-phosphate (abbreviated PI(3)P or PtdIns3P) and related to a process of autophagy. It is a subdomain of the endoplasmic reticulum (ER) membrane and has a morphology resembling Greek capital letter omega (Ω). Omegasomes are the sites from which phagophores form. Phagophores (also called isolation membranes) are sack-like structures that mature into autophagosomes that fuse with lysosomes in order to degrade the contents of the autophagosomes. The formation of omegasomes is increased as a response to starvation. Autophagy (from Greek words for self and eating) is a process of digesting or degrading cytoplasmic molecules (proteins, lipids, sugars and organelles). Macroautophagy is the main autophagic pathway, used primarily to eradicate damaged cell organelles such as mitochondria, ribosomes, etc. The omegasome is present at the opening of the sack-like phagophore while items destined for ...

TY - CHAP. T1 - Correlative light and electron microscopy of autophagosomes. AU - Gudmundsson, Sigurdur Runar. AU - Kahlhofer, Jenny. AU - Baylac, Nastassia. AU - Kallio, Katri Anneli. AU - Eskelinen, Eeva-Liisa. PY - 2019/1. Y1 - 2019/1. N2 - Live-cell imaging has been widely used to study autophagosome biogenesis and maturation. When combined with correlative electron microscopy, this approach can be extended to reveal ultrastructural details in three dimensions. The resolution of electron microscopy is needed when membrane contact sites and tubular connections between organelles are studied.. AB - Live-cell imaging has been widely used to study autophagosome biogenesis and maturation. When combined with correlative electron microscopy, this approach can be extended to reveal ultrastructural details in three dimensions. The resolution of electron microscopy is needed when membrane contact sites and tubular connections between organelles are studied.. KW - 1182 Biochemistry, cell and molecular ...

Author Summary The innate immune system represents a key barrier that fungal pathogens such as Candida albicans must overcome in order to disseminate through the host. C. albicans cells phagocytosed by macrophages initiate a complex program that involves a large-scale reprogramming of metabolism and transcription and results in the switch to a hyphal form that can penetrate and kill the macrophage. Though a number of signals are known to induce this morphological transition in vitro, what does so following phagocytosis has been unclear. We previously showed that C. albicans rapidly neutralizes acidic, nutrient-poor media that resembles the phagolysosome and that this is deficient in mutants impaired in amino acid import due to a mutation in STP2. In this paper, we investigate whether this happens within the macrophage as well. We show here that, in contrast to wild-type cells, stp2Δ mutants occupy an acidic phagosome and are unable to initiate hyphal differentiation. Because of this, they are more

Autophagy is a conserved cellular degradation pathway wherein double-membrane vesicle called autophagosomes capture long-lived proteins and damaged or superfluous organelles and deliver them to the lysosome for degradation. Septins are conserved GTP-binding proteins involved in many cellular processes, including phagocytosis and autophagy of intracellular bacteria, but no role in general autophagy was known. In budding yeast, septins polymerize into ring-shaped arrays of filaments required for cytokinesis. In an unbiased genetic screen and in subsequent targeted analysis, we found autophagy defects in septin mutants, and co-localized septins in rings at the pre-autophagosomal structure (PAS) and on autophagosomes where they physically interact with the autophagy proteins Atg8 and Atg9 ...

The autophagic pathway participates in many physiological and pathophysiological processes. Autophagy plays an important role, as part of the innate immune response, in the first line of defense against intruding pathogens. Recognition of pathogens by the autophagic machinery is mainly mediated by autophagic adaptors, proteins that simultaneously interact with specific cargos and components of the autophagic machinery. However, the exact mechanisms and signaling pathways regulating this step are largely unknown. TANK-binding kinase 1 (TBK1) has been recently implicated in the autophagic clearance of the bacterium Salmonella enterica. After its activation by the invading bacteria, TBK1 directly phosphorylated the autophagic adaptor optineurin (OPTN). This modification led to enhanced interaction of OPTN with the family of mammalian Atg8 proteins, which are ubiquitin-like and essential for autophagy. Such interaction allows the autophagic machinery to be recruited to the intracellular loci of the ...

Phagocytosis plays an essential role in host-defense mechanisms through the uptake and destruction of infectious pathogens. Specialized cell types including macrophages, neutrophils, and monocytes take part in this process in higher organisms. After opsonization with antibodies (IgG), foreign extracellular materials are recognized by Fc gamma receptors. Cross-linking of Fc gamma receptors initiates a variety of signals mediated by tyrosine phosphorylation of multiple proteins, which lead through the actin cytoskeleton rearrangements and membrane remodeling to the formation of phagosomes. Nascent phagosomes undergo a process of maturation that involves fusion with lysosomes. The acquisition of lysosomal proteases and release of reactive oxygen species are crucial for digestion of engulfed materials in phagosomes ...

We herein confirm the importance of nucleolin expression for LVS binding and its specificity as nucleolin is not involved in binding of another intracellular pathogen as L. monocytogenes or an inert particle. Association of nucleolin with F. tularensis during infection continues intracellularly after endocytosis of the bacteria. The present work therefore unravels for the first time the presence of nucleolin in the phagosomal compartment of macrophages.

With extension of the average lifespan, the ageing population has become a heavy burden for both society and individuals. Immune responses, key for the removal of pathogens and damage, are compromised in the elderly, making the elderly more susceptible to infections. In addition immune senescence is a risk factor for many late-onset diseases, such as cancer and atherosclerosis. Autophagy through degrading bulk cytoplasmic material maintains cytoplasmic health and cellular homeostasis [1]. We have found that it allows differentiation of immune cells [2] [3]. In previous work we showed that loss of autophagy in macrophages results in low-grade inflammation (inflamm-aging) and reduces innate and adaptive immune responses, typical of a senescent immune system. Autophagy induction rejuvenates immune responses in the elderly in T cells [3]. We have recently uncovered a novel pathway that controls the translation of autophagy proteins in T and B lymphocytes. Lymphocytes from old mice and elderly humans ...

Autophagy is the process through which the bulk degradation of cytoplasmic components by the lysosomal/vacuolar system occurs (Klionsky and Ohsumi, 1999), and it has a critical function in numerous biological processes (Mizushima, 2007). In autophagy, a double‐membrane structure called an autophagosome sequesters a portion of the cytoplasm and fuses with the lysosome/vacuole to deliver its contents into the organelle lumen (Baba et al, 1994). Genetic approaches in Saccharomyces cerevisiae have identified many autophagy‐related (ATG) genes involved in this process (Klionsky et al, 2003), and subsequent biochemical analyses have demonstrated that a novel ubiquitin‐like conjugation system called the Atg8 system is essential for autophagosome formation (Ichimura et al, 2000). In the Atg8 system, nascent Atg8 is cleaved at its C‐terminal arginine residue by Atg4, a cysteine protease (Kirisako et al, 2000), and the exposed C‐terminal glycine is conjugated to phosphatidylethanolamine (PE) by ...

FIGURE 1. The four principal manifestations of immunological autophagy. (1) Direct pathogen elimination assisted by SLRs and DAMP receptors. (A) Invading microbes either escaping the endosomes or phagosome (thin outline) or remaining in phagosomes that can be partially permeabilized (dotted outline) are captured by galectins and SLRs that recognize tags such as ubiquitin (small red circles) or diacylglycerol and β-galactoside (not shown) on damaged host membranes. The captured microbes or those cocaptured with the earmarked membranes are delivered into autophagic organelles (thick outline), starting with phagophores (crescents), progressing through autophagosomes (full white circles), and ending in degradative autolysosomes (full pink circles). SLRs possess an LC3 interacting region (LIR), phosphorylation sites (black dot, arbitrarily positioned), and a tag recognition domain (UBA, depicted for p62). Galectins (hatched square), considered to be DAMP receptors, have carbohydrate recognition ...

An siRNA screen for ATG protein depletion reveals the extent of the unconventional functions of the autophagy proteome in virus replication

Autophagy can be an conserved membrane trafficking procedure evolutionarily. phosphoinositide 3-kinases (PI3Ks) dissociates from development element receptor complexes and raises its discussion with the tiny GTPase Rab5. This p110β-Rab5 association maintains Rab5 in its GTP-bound condition and enhances the Rab5-Vps34 discussion that promotes autophagy. p110β mutants that neglect to connect to Rab5 are faulty in autophagy advertising. Therefore in mammalian cells p110β works as a molecular sensor for development SRT3109 element availability and induces autophagy by activating a Rab5-mediated SRT3109 signaling cascade. Intro Autophagy can be a membrane trafficking procedure that delivers intracellular material destined for degradation right into a dual membrane framework termed an autophagosome that after that fuses using the lysosome (Levine and Kroemer 2008 Levine and Yuan 2005 Mizushima et al. 2008 In metazoans the initiation of autophagy can be critically controlled by several phospholipids ...

Much of the initial definition of the genes and mechanisms involved in autophagy came from genetic studies of the yeast S. cerevisiae (14), and after subsequent work also with higher eukaryotes, dozens of autophagy proteins are now identified (11, 17). The complexity of the process is further underscored by proteomics analyses that link numerous known and putative autophagy-related proteins in protein complexes (1). One of the first autophagy proteins identified in yeast was Atg1 (originally called Apg1), a protein kinase that acts in a complex with Atg13 and Atg17 at an early stage in the induction of autophagy (11). Mammals have two orthologs of Atg1, called ULK1 and ULK2 (UNC-51-like kinases 1 and 2) (10). There is a mammalian ortholog of Atg13, and the ULK complex also contains FIP200, which may functionally be a counterpart of Atg17. As further described below, Atg1/ULK is a key regulator of autophagy from yeast to mammals, and protein phosphorylation events are central to the control of ...

Abstract: Autophagy is a highly conserved degradative pathway, essential for cellular homeostasis and implicated in diseases including cancer and neurodegeneration. Autophagy-related 8 (ATG8) proteins play a central role in autophagosome formation and selective delivery of cytoplasmic cargo to lysosomes by recruiting autophagy adaptors and receptors. The LC3-interacting region (LIR) docking site (LDS) of ATG8 proteins binds to LIR motifs present in autophagy adaptors and receptors. LIR-ATG8 interactions can be highly selective for specific mammalian ATG8 family members (LC3A-C, GABARAP, and GABARAPL1-2) and how this specificity is generated and regulated is incompletely understood. We have identified a LIR motif in the Golgi protein SCOC (short coiled-coil protein) exhibiting strong binding to GABARAP, GABARAPL1, LC3A and LC3C. The residues within and surrounding the core LIR motif of the SCOC LIR domain were phosphorylated by autophagy-related kinases (ULK1-3, TBK1) increasing specifically LC3 ...

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 ...

Nondegradative role of Atg5-Atg12/ Atg16L1 autophagy protein complex in antiviral activity of interferon gamma. Cell Host Microbe. 2012 Apr 19; 11(4):397-409 ...

Linkams CMS196 stage is being used to study cell behaviour by the London Research Institute of Cancer Research UK. In order for mammalian cells to remain healthy their components constantly have to be repaired or replaced. This constant upkeep is carried out in the cells through a process which is known as autophagy, from the Greek words auto self and phagein eat. As the name suggests, it involves the creation of a structure within the cell (the autophagosome) which breaks down and recycles old and dysfunctional components.. Autophagy plays a major role in a huge number of important cellular functions and any slight fault in this process can lead to neurodegenerative diseases and cancer.. With this catabolic mechanism being such a key part of the understanding of some cancers a team at the London Research Institute (LRI) of Cancer Research UK has been looking into how these autophagosomes are formed within the cells and how their functionality is directly linked to their external ...

Autophagy is a conserved process that delivers components of the cytoplasm to lysosomes for degradation. The E1 and E2 enzymes encoded by Atg7 and Atg3 are thought to be essential for autophagy involving the ubiquitin-like protein Atg8. Here, we describe an Atg7- and Atg3-independent autophagy pathway that facilitates programmed reduction of cell size during intestine cell death. Although multiple components of the core autophagy pathways, including Atg8, are required for autophagy and cells to shrink in the midgut of the intestine, loss of either Atg7 or Atg3 function does not influence these cellular processes. Rather, Uba1, the E1 enzyme used in ubiquitylation, is required for autophagy and reduction of cell size. Our data reveal that distinct autophagy programs are used by different cells within an animal, and disclose an unappreciated role for ubiquitin activation in autophagy.

PubMed comprises more than 30 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.

A movie that shows phagosome acidification and neutralization visualized using FITC-yeast. Amoebae of Dictyostelium discoideum were fed living budding...

CD47-specific antibodies and fusion proteins that block CD47-SIRPα signaling are employed as antitumor agents for several cancers. Here, we investigated the synergistic antitumor effect of simultaneously targeting CD47 and autophagy in non-small cell lung cancer (NSCLC). SIRPαD1-Fc, a novel CD47-targeting fusion protein, was generated and was found to increase the phagocytic and cytotoxic activities of macrophages against NSCLC cells. During this process, autophagy was markedly triggered, which was characterized by the three main stages of autophagic flux, including formation and accumulation of autophagosomes, fusion of autophagosomes with lysosomes, and degradation of autophagosomes in lysosomes. Meanwhile, reactive oxygen species and inactivation of mTOR were shown to be involved in autophagy initiation in SIRPαD1-Fc-treated cells, indicating a probable mechanism for autophagy activation after targeting CD47 by SIRPαD1-Fc. Inhibition of autophagy enhanced macrophage-mediated phagocytosis ...

We summarized the most recent findings on the role of autophagy in antiviral immune response. We described how viruses have developed strategies to subvert the autophagic process. A particular attention has been given to Epstein-Barr and Kaposi’s sarcoma associated Herpesvirus, viruses studied for many years in our laboratory. These two viruses belong to |i|γ|/i|-Herpesvirus subfamily and are associated with several human cancers. Besides the effects on the immune response, we have described how autophagy subversion by viruses may also concur to the enhancement of their replication and to viral tumorigenesis.

January 2016. Autophagy can act either as a tumor suppressor or as a survival mechanism for established tumors. To understand how autophagy plays this dual role in cancer, in vivo models are required. By using a highly heterogeneous C. elegans germline tumor, the research group of Christian Pohl in collaboration with the research group of Ivan Dikic could now show that autophagy-related proteins are expressed in a specific subset of tumor cells, the neurons. Moreover, they could demonstrate that inhibition of autophagy impairs neuronal differentiation and results in a shorter life span of animals with tumors. In contrast, induction of autophagy extends life span by impairing tumor proliferation, which also depends on modular changes in transcription networks and mitochondrial metabolism. The findings from this work, recently published in the journal Autophagy, suggest that metabolic restructuring, cell-type specific regulation of autophagy and neuronal differentiation play key roles in ...

We thank Rubinsztein and Nixon (1) for their interest in our study (2). We have the greatest respect for their contributions to the field of autophagy.. In our paper, we reported the discovery of compounds with related structures that stimulate autophagy in primary neurons by a pathway that is independent of the mammalian target of rapamycin (mTOR) (2). The lead compound mitigates against toxicity in two models of neurodegeneration (2). Using one conventional assay, the most potent compound in that series induced autophagy at least fivefold. Subsequently, we found analogs that induce autophagy 10-fold. Although not the focus of our study, we offered an assessment of the efficacy of rapamycin and said that it induces autophagy weakly, if at all, in primary neurons.. Using similar assays of autophagy, Boland et al. (3) reported a twofold induction by rapamycin in neurons and described it as robust. The appropriate adjective to describe the strength of an induction is admittedly subjective. ...

​​Summarizes the key players that function in autophagosome formation, elongation and maturation​ and its involvement in cancer progression Provides

It is established that interactions of proteins with RNA play a crucial role at regulating RNA fate. However, a recent work led by the Hentze lab at EMBL has discovered that the reverse relationship is also possible. In other words, proteins can be regulated by RNA. We refer to this phenomenon as riboregulation.. This study shows that the RNA vault 1-1 (vtRNA1-1) interacts and regulates the protein p62, which is a key component of the autophagy machinery. As its name suggests, autophagy is a process by which a cell eats itself to recycle its unnecessary or dysfunctional components. Interaction of vtRNA1-1 with p62 inhibits autophagy and this regulatory circuit exists in both human and mouse cells. Importantly, the amount of vtRNA1-1 inside a cell varies according to the cells nutritional status. When is deprived of amino acids, vtRNA1-1 is reduced to enhance autophagy that will refill the pool of amino acids from unnecessary proteins to cover the cell needs. This study raises the question ...

Rabbit Polyclonal Anti-LC3A Antibody - Azide Free. Autophagosome Marker. Validated: WB, IHC-P. Tested Reactivity: Human, Mouse, Rat, and more. 100% Guaranteed.

Cells of our immune system kill pathogens by enclosing them in a compartment called the phagosome. The pathogen-containing phagosome is physically transported to execution chambers (lysosomes) by nanoscale Motor proteins. Researchers at TIFR show that cholesterol is needed to cluster many Motors on the phagosomes surface. This assembles an army of Motors that carries the phagosome to the execution chamber. Cholesterol, that much dreaded name, therefore also keeps us healthy by helping to kill bugs.

Description: The chemical reactions and pathways resulting in the breakdown of carbohydrates, any of a group of organic compounds based of the general formula Cx(H2O)y, as carried out by individual cells.. ...

Autophagy is a key cellular process that involves the degradation of a cells own components through the lysosome machinery. Recent studies suggest that autophagy proteins can also participate in diverse non‐autophagy‐related cellular processes. This review discusses the growing number of non‐autophagy roles of autophagy‐related proteins. ...

Autophagy is a conserved homeostatic process active in all human cells and affecting a spectrum of diseases. Here we use a pharmaceutical screen to discover new mechanisms for activation of autophagy. We identify a subset of pharmaceuticals inducing autophagic flux with effects in diverse cellular s …

Phagocytosis is a form of endocytosis where a cell modifies its plasma membrane to engulf and internalize external matter, creating a phagosome.

NL-1 NL-1 is a mitoNEET inhibitor with antileukemic effect. NL-1 inhibits REH and REH/Ara-C cells growth with IC50s of 47.35 µM and 56.26 µM, respectively. NL-1-mediated death in leukemic cells requires the activation of the autophagic pathway.. ...

The C42 enhances autophagy via GSK3 signaling pathway. (A) Electron microscopy was performed on vehicle (ctrl) and the C42-treated (0.5 μmol/L, 3 h) HCT116 c

Today we thought it was a good time to take a look at a new study that demonstrates that increasing autophagy is a good approach to slowing aging and could...