Membrane-bound cytoplasmic vesicles formed by invagination of phagocytized material. They fuse with lysosomes to form phagolysosomes in which the hydrolytic enzymes of the lysosome digest the phagocytized material.
The engulfing and degradation of microorganisms; other cells that are dead, dying, or pathogenic; and foreign particles by phagocytic cells (PHAGOCYTES).
A class of morphologically heterogeneous cytoplasmic particles in animal and plant tissues characterized by their content of hydrolytic enzymes and the structure-linked latency of these enzymes. The intracellular functions of lysosomes depend on their lytic potential. The single unit membrane of the lysosome acts as a barrier between the enzymes enclosed in the lysosome and the external substrate. The activity of the enzymes contained in lysosomes is limited or nil unless the vesicle in which they are enclosed is ruptured. Such rupture is supposed to be under metabolic (hormonal) control. (From Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)
Ubiquitously expressed integral membrane glycoproteins found in the LYSOSOME.
The relatively long-lived phagocytic cell of mammalian tissues that are derived from blood MONOCYTES. Main types are PERITONEAL MACROPHAGES; ALVEOLAR MACROPHAGES; HISTIOCYTES; KUPFFER CELLS of the liver; and OSTEOCLASTS. They may further differentiate within chronic inflammatory lesions to EPITHELIOID CELLS or may fuse to form FOREIGN BODY GIANT CELLS or LANGHANS GIANT CELLS. (from The Dictionary of Cell Biology, Lackie and Dow, 3rd ed.)
A genetically related subfamily of RAB GTP-BINDING PROTEINS involved in transport from the cell membrane to early endosomes. This enzyme was formerly listed as EC 3.6.1.47.
The adherence and merging of cell membranes, intracellular membranes, or artificial membranes to each other or to viruses, parasites, or interstitial particles through a variety of chemical and physical processes.
A species of gram-negative, aerobic bacteria that is the causative agent of LEGIONNAIRES' DISEASE. It has been isolated from numerous environmental sites as well as from human lung tissue, respiratory secretions, and blood.
Cytoplasmic vesicles formed when COATED VESICLES shed their CLATHRIN coat. Endosomes internalize macromolecules bound by receptors on the cell surface.
A large family of MONOMERIC GTP-BINDING PROTEINS that play a key role in cellular secretory and endocytic pathways. EC 3.6.1.-.
The engulfing of liquids by cells by a process of invagination and closure of the cell membrane to form fluid-filled vacuoles.
Any spaces or cavities within a cell. They may function in digestion, storage, secretion, or excretion.
Small uniformly-sized spherical particles, of micrometer dimensions, frequently labeled with radioisotopes or various reagents acting as tags or markers.
A milky, product excreted from the latex canals of a variety of plant species that contain cauotchouc. Latex is composed of 25-35% caoutchouc, 60-75% water, 2% protein, 2% resin, 1.5% sugar & 1% ash. RUBBER is made by the removal of water from latex.(From Concise Encyclopedia Biochemistry and Molecular Biology, 3rd ed). Hevein proteins are responsible for LATEX HYPERSENSITIVITY. Latexes are used as inert vehicles to carry antibodies or antigens in LATEX FIXATION TESTS.
A bacterium causing tuberculosis in domestic fowl and other birds. In pigs, it may cause localized and sometimes disseminated disease. The organism occurs occasionally in sheep and cattle. It should be distinguished from the M. avium complex, which infects primarily humans.
Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.
An abundant lysosomal-associated membrane protein that has been found to shuttle between LYSOSOMES; ENDOSOMES; and the PLASMA MEMBRANE. In PLATELETS and T-LYMPHOCYTES it may play a role in the cellular degranulation process.
An abundant lysosomal-associated membrane protein that has been found to shuttle between LYSOSOMES; ENDOSOMES; and the PLASMA MEMBRANE. Loss of expression of lysosomal-associated membrane protein 2 is associated with GLYCOGEN STORAGE DISEASE TYPE IIB.
An intracellular proteinase found in a variety of tissue. It has specificity similar to but narrower than that of pepsin A. The enzyme is involved in catabolism of cartilage and connective tissue. EC 3.4.23.5. (Formerly EC 3.4.4.23).
Established cell cultures that have the potential to propagate indefinitely.
Thorium oxide (ThO2). A radiographic contrast agent that was used in the early 1930s through about 1954. High rates of mortality have been linked to its use and it has been shown to cause liver cancer.
An organization of cells into an organ-like structure. Organoids can be generated in culture. They are also found in certain neoplasms.
A species of gram-positive, aerobic bacteria that produces TUBERCULOSIS in humans, other primates, CATTLE; DOGS; and some other animals which have contact with humans. Growth tends to be in serpentine, cordlike masses in which the bacilli show a parallel orientation.
Thin structures that encapsulate subcellular structures or ORGANELLES in EUKARYOTIC CELLS. They include a variety of membranes associated with the CELL NUCLEUS; the MITOCHONDRIA; the GOLGI APPARATUS; the ENDOPLASMIC RETICULUM; LYSOSOMES; PLASTIDS; and VACUOLES.
An enzyme that catalyzes the conversion of an orthophosphoric monoester and water to an alcohol and orthophosphate. EC 3.1.3.2.
A flavoprotein enzyme that catalyzes the univalent reduction of OXYGEN using NADPH as an electron donor to create SUPEROXIDE ANION. The enzyme is dependent on a variety of CYTOCHROMES. Defects in the production of superoxide ions by enzymes such as NADPH oxidase result in GRANULOMATOUS DISEASE, CHRONIC.
Ubiquitously-expressed tetraspanin proteins that are found in late ENDOSOMES and LYSOSOMES and have been implicated in intracellular transport of proteins.
A species of gram-positive, rod-shaped bacteria widely distributed in nature. It has been isolated from sewage, soil, silage, and from feces of healthy animals and man. Infection with this bacterium leads to encephalitis, meningitis, endocarditis, and abortion.
Filamentous proteins that are the main constituent of the thin filaments of muscle fibers. The filaments (known also as filamentous or F-actin) can be dissociated into their globular subunits; each subunit is composed of a single polypeptide 375 amino acids long. This is known as globular or G-actin. In conjunction with MYOSINS, actin is responsible for the contraction and relaxation of muscle.
Granular leukocytes having a nucleus with three to five lobes connected by slender threads of chromatin, and cytoplasm containing fine inconspicuous granules and stainable by neutral dyes.
Chemical compounds which yield hydrogen ions or protons when dissolved in water, whose hydrogen can be replaced by metals or basic radicals, or which react with bases to form salts and water (neutralization). An extension of the term includes substances dissolved in media other than water. (Grant & Hackh's Chemical Dictionary, 5th ed)
An emotional attitude excited by realization of a shortcoming or impropriety.
Proton-translocating ATPases that are involved in acidification of a variety of intracellular compartments.
Mode of communication wherein a bound hormone affects the function of the cell type that produced the hormone.
A protein of the annexin family that catalyzes the conversion of 1-D-inositol 1,2-cyclic phosphate and water to 1-D-myo-inositol 1-phosphate.
Phosphatidylinositols in which one or more alcohol group of the inositol has been substituted with a phosphate group.
Condensed areas of cellular material that may be bounded by a membrane.
Specific particles of membrane-bound organized living substances present in eukaryotic cells, such as the MITOCHONDRIA; the GOLGI APPARATUS; ENDOPLASMIC RETICULUM; LYSOSOMES; PLASTIDS; and VACUOLES.
Cellular uptake of extracellular materials within membrane-limited vacuoles or microvesicles. ENDOSOMES play a central role in endocytosis.
A family of gram-positive bacteria found in soil and dairy products and as parasites on animals and man. Several are important pathogens.
An oxyacid of chlorine (HClO) containing monovalent chlorine that acts as an oxidizing or reducing agent.
Microscopy of specimens stained with fluorescent dye (usually fluorescein isothiocyanate) or of naturally fluorescent materials, which emit light when exposed to ultraviolet or blue light. Immunofluorescence microscopy utilizes antibodies that are labeled with fluorescent dye.
Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.
The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
The process of altering the morphology and functional activity of macrophages so that they become avidly phagocytic. It is initiated by lymphokines, such as the macrophage activation factor (MAF) and the macrophage migration-inhibitory factor (MMIF), immune complexes, C3b, and various peptides, polysaccharides, and immunologic adjuvants.
The process of moving proteins from one cellular compartment (including extracellular) to another by various sorting and transport mechanisms such as gated transport, protein translocation, and vesicular transport.
The layer of pigment-containing epithelial cells in the RETINA; the CILIARY BODY; and the IRIS in the eye.
Mononuclear phagocytes derived from bone marrow precursors but resident in the peritoneum.
A saprophytic bacterium widely distributed in soil and dust and on plants.
A genus of gram-positive, aerobic bacteria. Most species are free-living in soil and water, but the major habitat for some is the diseased tissue of warm-blooded hosts.
Proteins that bind to particles and cells to increase susceptibility to PHAGOCYTOSIS, especially ANTIBODIES bound to EPITOPES that attach to FC RECEPTORS. COMPLEMENT C3B may also participate.
Microscopy in which the samples are first stained immunocytochemically and then examined using an electron microscope. Immunoelectron microscopy is used extensively in diagnostic virology as part of very sensitive immunoassays.
The bovine variety of the tubercle bacillus. It is called also Mycobacterium tuberculosis var. bovis.
A moderate-growing, photochromogenic species found in aquariums, diseased fish, and swimming pools. It is the cause of cutaneous lesions and granulomas (swimming pool granuloma) in humans. (Dorland, 28th ed)
The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.
Specific molecular sites on the surface of various cells, including B-lymphocytes and macrophages, that combine with IMMUNOGLOBULIN Gs. Three subclasses exist: Fc gamma RI (the CD64 antigen, a low affinity receptor), Fc gamma RII (the CD32 antigen, a high affinity receptor), and Fc gamma RIII (the CD16 antigen, a low affinity receptor).
The process by which antigen is presented to lymphocytes in a form they can recognize. This is performed by antigen presenting cells (APCs). Some antigens require processing before they can be recognized. Antigen processing consists of ingestion and partial digestion of the antigen by the APC, followed by presentation of fragments on the cell surface. (From Rosen et al., Dictionary of Immunology, 1989)
A light microscopic technique in which only a small spot is illuminated and observed at a time. An image is constructed through point-by-point scanning of the field in this manner. Light sources may be conventional or laser, and fluorescence or transmitted observations are possible.
Techniques to partition various components of the cell into SUBCELLULAR FRACTIONS.

Role of iron in Nramp1-mediated inhibition of mycobacterial growth. (1/1859)

Innate resistance to mycobacterial growth is mediated by a gene, Nramp1. We have previously reported that Nramp1 mRNA from macrophages of Mycobacterium bovis BCG-resistant (Bcgr) mice is more stable than Nramp1 mRNA from macrophages of BCG-susceptible (Bcgs) mice. Based on these observations and on reports that show that the closely related Nramp2 gene is a metal ion transporter, we evaluated the effect of iron on the growth of Mycobacterium avium within macrophages as well as on the stability of Nramp1 mRNA. The addition of iron to macrophages from Bcgs mice resulted in a stimulation of mycobacterial growth. In contrast, iron increased the capacity of macrophages from Bcgr mice to control the growth of M. avium. When we treated recombinant gamma interferon (IFN-gamma)-activated macrophages with iron, we found that iron abrogated the growth inhibitory effect of IFN-gamma-activated macrophages from Bcgs mice but that it did not affect the capacity of macrophages from Bcgr mice to control microbial growth. A more detailed examination of the effect of iron on microbial growth showed that the addition of small quantities of iron to resident macrophages from Bcgr mice stimulated antimicrobial activity within a very narrow dose range. The effect of iron on the growth inhibitory activity of macrophages from Bcgr mice was abrogated by the addition of catalase or mannitol to the culture medium. These results are consistent with an Fe(II)-mediated stimulation of the Fenton/Haber-Weiss reaction and hydroxyl radical-mediated inhibition of mycobacterial growth.  (+info)

Killing kinetics of intracellular Afipia felis treated with amikacin. (2/1859)

Afipia felis is a facultative intracellular bacterium which multiplies in macrophages following inhibition of phagosome-lysosome (P-L) fusion. When A. felis-infected cells are incubated for 72 h with various antibiotics, only aminoglycosides are found to be bactericidal. We therefore studied the killing of intracellular A. felis by amikacin, and its relationship with the restoration of P-L fusion. Amikacin reduced the number of A. felis from 8.5 x 10(5) to 3.5 x 102 cfu/mL within 94 h. P-L fusion was restored after 30-40 h of incubation with amikacin. Both mechanisms may participate in the intracellular killing of bacteria.  (+info)

Acidification of the phagosome in Crassostrea virginica hemocytes following engulfment of zymosan. (3/1859)

Phagocytic hemocytes are responsible for engulfing and internally degrading foreign organisms within the hemolymph and tissue of the eastern oyster, Crassostrea virginica. Since rapid acidification of the phagosome lumen is typically essential for activation of hydrolytic and reactive oxygen intermediate (ROI) producing enzymes in vertebrate cells, we measured phagosomal pH in oyster hemocytes by using the emission fluorescence of two fluorescent probes, rhodamine and Oregon Green 488 (OG 488), conjugated to zymosan to determine whether oyster hemocyte phagosomes become acidified after phagocytosis of zymosan. The average pH of 1079 phagosomes within 277 hemocytes 1 h after phagocytosis of zymosan was 3.9 +/- 0.03. Observations of 141 hemocytes with internalized zymosan by light microscopy revealed that, over a 60-min time period, 51% of highly granular hemocytes became partially granular, and 29% became agranular. In addition, 83% of partially granular hemocytes containing zymosan at time = 0 became agranular within 60 min. A comparison revealed that the phagosomes of agranular hemocytes were much more acidic (pH 3.1 +/- 0.02) than those of highly granular hemocytes (4.9 +/- 0.02; P < 0.05). These values are significantly lower than most reported in the literature for blood cells from metazoan organisms.  (+info)

Phagosomes are fully competent antigen-processing organelles that mediate the formation of peptide:class II MHC complexes. (4/1859)

During the processing of particulate Ags, it is unclear whether peptide:class II MHC (MHC-II) complexes are formed within phagosomes or within endocytic compartments that receive Ag fragments from phagosomes. Murine macrophages were pulsed with latex beads conjugated with OVA. Flow or Western blot analysis of isolated phagosomes showed extensive acquisition of MHC-II, H-2M, and invariant chain within 30 min, with concurrent degradation of OVA. T hybridoma responses to isolated subcellular fractions demonstrated OVA (323-339):I-Ad complexes in phagosomes and plasma membrane but not within dense late endocytic compartments. Furthermore, when two physically separable sets of phagosomes were present within the same cells, OVA(323-339):I-Ad complexes were demonstrated in latex-OVA phagosomes but not in phagosomes containing latex beads conjugated with another protein. This implies that these complexes were formed specifically within phagosomes and were not formed elsewhere and subsequently transported to phagosomes. In addition, peptide:MHC-II complexes were shown to traffic from phagosomes to the cell surface. In conclusion, phagosomes are fully competent to process Ags and generate peptide:MHC-II complexes that are transported to the cell surface and presented to T cells.  (+info)

Modulation of endocytosis in nuclear factor IL-6(-/-) macrophages is responsible for a high susceptibility to intracellular bacterial infection. (5/1859)

Activated macrophages kill bacteria, a function known to depend on the expression of NF-IL-6. Here, it is demonstrated that the attenuated Brucella abortus vaccine strain 19 replicates much better in NF-IL-6-/- than in NF-IL-6(+/+) and NF-IL-6(+/+)-activated murine macrophages and at levels comparable to those observed in normal macrophages infected with the pathogenic strain 2308. The role of NF-IL-6 in the inhibition of intracellular bacterial replication is related to its control of endocytosis and membrane fusion between endosomes and Brucella-containing phagosomes. Addition of the granulocyte-CSF (G-CSF), whose induction is impaired in NF-IL-6(-/-) macrophages, restores both endocytosis and the morphology of endosomes, together with bactericidal activity. Regulation of membrane traffic in endocytosis by G-CSF whose expression is controlled by NF-IL-6 may explain how a host cell can control intracellular bacterial replication.  (+info)

Cloning and sequencing of a protein involved in phagosomal membrane fusion in Paramecium. (6/1859)

An mAb was raised to the C5 phagosomal antigen in Paramecium multimicronucleatum. To determine its function, the cDNA and genomic DNA encoding C5 were cloned. This antigen consisted of 315 amino acid residues with a predicted molecular weight of 36,594, a value similar to that determined by SDS-PAGE. Sequence comparisons uncovered a low but significant homology with a Schizosaccharomyces pombe protein and the C-terminal half of the beta-fructofuranosidase protein of Zymomonas mobilis. Lacking an obvious transmembrane domain or a possible signal sequence at the N terminus, C5 was predicted to be a soluble protein, whereas immunofluorescence data showed that it was present on the membranes of vesicles and digestive vacuoles (DVs). In cells that were minimally permeabilized but with intact DVs, C5 was found to be located on the cytosolic surface of the DV membranes. Immunoblotting of proteins from the purified and KCl-washed DVs showed that C5 was tightly bound to the DV membranes. Cryoelectron microscopy also confirmed that C5 was on the cytosolic surface of the discoidal vesicles, acidosomes, and lysosomes, organelles known to fuse with the membranes of the cytopharynx, the DVs of stages I (DV-I) and II (DV-II), respectively. Although C5 was concentrated more on the mature than on the young DV membranes, the striking observation was that the cytopharyngeal membrane that is derived from the discoidal vesicles was almost devoid of C5. Approximately 80% of the C5 was lost from the discoidal vesicle-derived membrane after this membrane fused with the cytopharyngeal membrane. Microinjection of the mAb to C5 greatly inhibited the fusion of the discoidal vesicles with the cytopharyngeal membrane and thus the incorporation of the discoidal vesicle membranes into the DV membranes. Taken together, these results suggest that C5 is a membrane protein that is involved in binding and/or fusion of the discoidal vesicles with the cytopharyngeal membrane that leads to DV formation.  (+info)

RacF1, a novel member of the Rho protein family in Dictyostelium discoideum, associates transiently with cell contact areas, macropinosomes, and phagosomes. (7/1859)

Using a PCR approach we have isolated racF1, a novel member of the Rho family in Dictyostelium. The racF1 gene encodes a protein of 193 amino acids and is constitutively expressed throughout the Dictyostelium life cycle. Highest identity (94%) was found to a RacF2 isoform, to Dictyostelium Rac1A, Rac1B, and Rac1C (70%), and to Rac proteins of animal species (64-69%). To investigate the role of RacF1 in cytoskeleton-dependent processes, we have fused it at its amino-terminus with green fluorescent protein (GFP) and studied the dynamics of subcellular redistribution using a confocal laser scanning microscope and a double-view microscope system. GFP-RacF1 was homogeneously distributed in the cytosol and accumulated at the plasma membrane, especially at regions of transient intercellular contacts. GFP-RacF1 also localized transiently to macropinosomes and phagocytic cups and was gradually released within <1 min after formation of the endocytic vesicle or the phagosome, respectively. On stimulation with cAMP, no enrichment of GFP-RacF1 was observed in leading fronts, from which it was found to be initially excluded. Cell lines were obtained using homologous recombination that expressed a truncated racF1 gene lacking sequences encoding the carboxyl-terminal region responsible for membrane targeting. These cells displayed normal phagocytosis, endocytosis, and exocytosis rates. Our results suggest that RacF1 associates with dynamic structures that are formed during pinocytosis and phagocytosis. Although RacF1 appears not to be essential, it might act in concert and/or share functions with other members of the Rho family in the regulation of a subset of cytoskeletal rearrangements that are required for these processes.  (+info)

Increased expression of Rab5a correlates directly with accelerated maturation of Listeria monocytogenes phagosomes. (8/1859)

Previous studies have shown that Listeria monocytogenes (LM) modulates phagocytic membrane traffic. Here we explore whether Rab5a, a GTPase associated with phagosome-endosome fusion, is related to phagosome maturation and to the intracellular survival of LM. Stable transfection of Rab5a cDNA into macrophages accelerates intracellular degradation of LM. Morphological studies confirmed that phagosome maturation and phagosome-lysosome fusion is enhanced by overexpression of Rab5a. Down-regulation experiments using antisense oligonucleotides targeted to the Rab5a mRNA efficiently reduced Rab5a synthesis, reduced phagosome-endosome traffic, blocked phagosome-lysosome fusion, and extended intraphagosomal survival of LM. Down-regulation of Rab5a had no effect on LM internalization. Down-regulation of Rab5c had no effect on phagosome maturation and phagosome-lysosome fusion. The results indicate that Rab5a controls early phagosome-endosome interactions and governs the maturation of the early phagosome leading to phagosome-lysosome fusion.  (+info)

Survival of Salmonella typhimurium within macrophage phagosomes requires the coordinate expression of bacterial gene products. This report examines the contribution of phagosomal pH as a signal for expression of genes positively regulated by the S. typhimurium virulence regulators PhoP and PhoQ. Several hours after bacterial phagocytosis by murine bone marrow-derived macrophages, PhoP-activated gene transcription increased 50- to 77-fold. In contrast, no difference in PhoP-activated gene expression was observed after infection of cultured epithelial cells, suggesting that the membrane sensor PhoQ recognized signals unique to macrophage phagosomes. The increase in PhoP-regulated gene expression was abolished when macrophage culture medium contained NH4Cl or chloroquine, weak bases that raise the pH of acidic compartments. Measurements of pH documented that S. typhimurium delayed and attenuated acidification of its intracellular compartment. Phagosomes containing S. typhimurium required 4-5 hr to ...
Apoptotic cells generated by programmed cell death are engulfed by phagocytes and enclosed within membrane-bound phagosomes. Maturation of apoptotic cell-containing phagosomes leads to formation of phagolysosomes where cell corpses are degraded. The class III phosphatidylinositol 3-kinase (PI3-kinase) VPS-34 coordinates with PIKI-1, a class II PI3-kinase, to produce PtdIns3P on phagosomes, thus promoting phagosome closure and maturation. Here, we identified UBC-13, an E2 ubiquitin-conjugating enzyme that functions in the same pathway with VPS-34 but in parallel to PIKI-1 to regulate PtdIns3P generation on phagosomes. Loss of ubc-13 affects early steps of phagosome maturation, causing accumulation of cell corpses. We found that UBC-13 functions with UEV-1, a noncatalytic E2 variant, and CHN-1, a U-box-containing E3 ubiquitin ligase, to catalyze K63-linked poly-ubiquitination on VPS-34 both in vitro and in Caenorhabditis elegans. Loss of ubc-13, uev-1, or chn-1 disrupts ubiquitin modification of ...
A prequel to endosomal maturation into late endosomal/lysosomal organelles is Rab conversion (Rink et al., 2005). This term describes a process whereby an organelle synchronously sheds off early endosomal Rab(s) and concomitantly receives the late endosomal Rab, Rab7 (Rink et al., 2005). The signals for this transition are currently unknown (Deretic, 2005). We wondered whether Rab conversion applies to phagosomes, and whether Rab22a, as a candidate terminal recycling Rab involved in cargo and membrane sorting from the early endosome (Mesa et al., 2001; Weigert et al., 2004), could supply or contribute to such signals. To test this, we examined Rab7 acquisition by the mycobacterial phagosome, which was previously shown to exclude this critical late endocytic Rab (Via et al., 1997). Unlike in cells treated with control scrambled siRNA, Rab7 acquisition was increased to 80% on live mycobacterial phagosomes in macrophages in which Rab22a was knocked down by siRNA (Fig. 5). These findings are ...
Nascent phagosomes need to undergo a series of fusion and fission reactions to acquire the microbicidal properties required for the innate immune response. form of RILP lacking the dynein-dynactin-recruiting domain. We conclude that full maturation of phagosomes requires the retrograde emission of tubular extensions which are generated by activation of Rab7 recruitment of RILP and consequent association of phagosomes with microtubule-associated motors. Leukocytes eliminate pathogens and apoptotic cells by in the beginning engulfing them into a phagocytic vacuole. The vacuole which is derived from the plasmalemma needs to undergo extensive remodeling to acquire microbicidal and lytic capabilities (28). Such remodeling also known as maturation entails sequential fusion with numerous components of the endolysosomal pathway and concomitant fission E 2012 events that maintain the vacuolar size nearly constant (1 28 The molecular machinery underlying maturation particularly the E 2012 process of ...
Starvation-induced autophagosomes engulf cytosol and/or organelles and deliver them to lysosomes for degradation, thereby resupplying depleted nutrients. Despite advances in understanding the molecular basis of this process, the membrane origin of autophagosomes remains unclear. Here, we demonstrate that, in starved cells, the outer membrane of mitochondria participates in autophagosome biogenesis. The early autophagosomal marker, Atg5, transiently localizes to punctae on mitochondria, followed by the late autophagosomal marker, LC3. The tail-anchor of an outer mitochondrial membrane protein also labels autophagosomes and is sufficient to deliver another outer mitochondrial membrane protein, Fis1, to autophagosomes. The fluorescent lipid NBD-PS (converted to NBD-phosphotidylethanolamine in mitochondria) transfers from mitochondria to autophagosomes. Photobleaching reveals membranes of mitochondria and autophagosomes are transiently shared. Disruption of mitochondria/ER connections by mitofusin2 ...
Cecilia Czibener, Nathan M. Sherer, Steven M. Becker, Marc Pypaert, Enfu Hui, Edwin R. Chapman, Walther Mothes, Norma W. Andrews; Ca2+ and synaptotagmin VII-dependent delivery of lysosomal membrane to nascent phagosomes . J Exp Med 2 October 2006; 203 (10): i26. doi: https://doi.org/10.1084/JEM20310OIA26. Download citation file:. ...
M tuberculosis is an intracellular pathogen with the ability to persist in the early phagosomal compartment.2 It arrests phagosome maturation at an early stage and strongly inhibits phagolysosome fusion. The phagolysosome is a rather hostile environment, where many bacterial pathogens are killed. The early phagosome is a less hostile compartment where M tuberculosis can accommodate itself. Yet, arrest of phagosome maturation by M tuberculosis is not complete and some bacteria are killed or at least prohibited from replication through antibacterial mechanisms including reactive oxygen and nitrogen intermediates, which are produced by activated macrophages (fig 1). The different T cell populations produce interferon γ (IFNγ) and hence are of the T helper 1 (Th1) type. This cytokine is the central mediator of macrophage activation. IFNγ synergises with tumour necrosis factor α (TNFα) in activating macrophages. CD4 T cells also produce lymphotoxin α (LTα), which participates in protection ...
You are viewing: Isolation membrane. Isolation membranes, also known as phagophores, are membrane structures involved in autophagosome formation.
Antigen (Ag) crosspresentation by dendritic cells (DCs) involves the presentation of internalized Ags on MHC class I molecules to initiate CD8+ T
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 - ...
The pathogenesis of mycobacterial infection is associated with an ability to interfere with maturation of the phagosomal compartment after ingestion by macrophages. Identification of the mycobacterial components that contribute to this phenomenon will allow rational design of novel approaches to the treatment and prevention of tuberculosis. Microarray-based screening of a transposon library was used to identify mutations that influence the fate of Mycobacterium bovis bacille Calmette-Guérin (BCG) following uptake by macrophages. A screen based on bacterial survival during a 3-d infection highlighted genes previously implicated in growth of Mycobacterium tuberculosis in macrophages and in mice, together with a number of other virulence genes including a locus encoding virulence-associated membrane proteins and a series of transporter molecules. A second screen based on separation of acidified and non-acidified phagosomes by flow cytometry identified genes involved in mycobacterial control of early
The interaction of (Mtb) with sponsor cell death signaling Flumatinib mesylate pathways is characterized by an initial anti-apoptotic phase followed by a pro-necrotic phase to allow for sponsor cell exit of the bacteria. phagocytic cells Mtb resides within a altered phagosomal compartment and IL2RG inhibits apoptotic sponsor cell death. Recent studies possess shown that Mtb eventually translocates from your phagosomal compartment to the cytosol. This event is definitely followed by the induction of necrotic sponsor cell death allowing the bacteria to exit the sponsor cell and infect naive cell populations. Our study adds to this relatively unexplored aspect of Mtb pathogenesis by exposing the transcriptional repressor of Mtb negatively regulates phagosomal escape and sponsor cell necrosis. We furthermore demonstrate the improved necrosis induction from the Mtb mutant strain deficient in required elevated reactive oxygen species levels within sponsor cell mitochondria and reduced activation of ...
The crack isolation membrane for tile can be quite a focus inside the place were fantastic. It can be covered by you with tile, lumber, metal, or rock with respect to the style of the search and also your kitchen you desire. crack isolation membrane for tile.
Trost M., English L., Lemieux S., Courcelles M., Desjardins M., Thibault P.. The ability of macrophages to clear pathogens and elicit a sustained immune response is regulated by various cytokines, including interferon-gamma (IFN-gamma). To investigate the molecular mechanisms by which IFN-gamma modulates phagosome functions, we profiled the changes in composition, abundance, and phosphorylation of phagosome proteins in resting and activated macrophages by using quantitative proteomics and bioinformatics approaches. We identified 2415 phagosome proteins together with 2975 unique phosphorylation sites with a high level of sensitivity. Using network analyses, we determined that IFN-gamma delays phagosomal acquisition of lysosomal hydrolases and peptidases for the gain of antigen presentation. Furthermore, this gain in antigen presentation is dependent on phagosomal networks of the actin cytoskeleton and vesicle-trafficking proteins, as well as Src kinases and calpain proteases. Major ...
In cell biology, a phagosome is a vesicle formed around a particle engulfed by a phagocyte via phagocytosis. Professional phagocytes include macrophages, neutrophils, and dendritic cells (DCs). A phagosome is formed by the fusion of the cell membrane around a microorganism or senescent cell. Phagosomes have membrane-bound proteins to recruit and fuse with lysosomes to form mature phagolysosomes. The lysosomes contain hydrolytic enzymes and reactive oxygen species (ROS) which kill and digest the pathogens. Phagosomes can also form in non-professional phagocytes, but they can only engulf a smaller range of particles, and do not contain ROS. The useful materials (e.g. amino acids) from the digested particles are moved into the cytosol, and waste is removed by exocytosis. Phagosome formation is crucial for tissue homeostasis and both innate and adaptive host defense against pathogens. However, some bacteria can exploit phagocytosis as an invasion strategy. They either reproduce inside of the ...
The initial step of autophagosome formation of an omegasome on the endoplasmic reticulum, followed by of elongation of structures called phagophores.[3]. The formation of autophagosomes is controlled by Atg genes through Atg12-Atg5 and LC3 complexes. The conjugate of Atg12-Atg5 also interacts with Atg16 to form larger complexes. Modification of Atg5 by Atg12 is essential for the elongation of the initial membrane.[4]. After the formation of the spherical structure, the complex of ATG12-ATG5:ATG16L1 dissociates from the autophagosome. LC3 is cleaved by ATG4 protease to generate cytosolic LC3. LC3 cleavage is required for the terminal fusion of an autophagosome with its target membrane. LC3 is commonly used as a marker of autophagosomes in immunocytochemistry, because it is the essential part of the vesicle and stays associated until the last moment before its fusion. At first, autophagosomes fuse with endosomes or endosome-derived vesicles. These structures are then called amphisomes or ...
Phagocytosis is the process of taking in relatively large particles by a cell, and is a central mechanism in the tissue remodeling, inflammation, and defense against infectious agents. A phagosome is formed when the specific receptors on the phagocyte surface recognize ligands on the particle surface. After formation, nascent phagosomes progressively acquire digestive characteristics. This maturation of phagosomes involves regulated interaction with the other membrane organelles, including recycling endosomes, late endosomes and lysosomes. The fusion of phagosomes and lysosomes releases toxic products that kill most bacteria and degrade them into fragments. However, some bacteria have strategies to escape the bactericidal mechanisms associated with phagocytosis and survive within host phagocytes ...
Phagocytosis is the process of taking in relatively large particles by a cell, and is a central mechanism in the tissue remodeling, inflammation, and defense against infectious agents. A phagosome is formed when the specific receptors on the phagocyte surface recognize ligands on the particle surface. After formation, nascent phagosomes progressively acquire digestive characteristics. This maturation of phagosomes involves regulated interaction with the other membrane organelles, including recycling endosomes, late endosomes and lysosomes. The fusion of phagosomes and lysosomes releases toxic products that kill most bacteria and degrade them into fragments. However, some bacteria have strategies to escape the bactericidal mechanisms associated with phagocytosis and survive within host phagocytes ...
Phagocytosis is the process of taking in relatively large particles by a cell, and is a central mechanism in the tissue remodeling, inflammation, and defense against infectious agents. A phagosome is formed when the specific receptors on the phagocyte surface recognize ligands on the particle surface. After formation, nascent phagosomes progressively acquire digestive characteristics. This maturation of phagosomes involves regulated interaction with the other membrane organelles, including recycling endosomes, late endosomes and lysosomes. The fusion of phagosomes and lysosomes releases toxic products that kill most bacteria and degrade them into fragments. However, some bacteria have strategies to escape the bactericidal mechanisms associated with phagocytosis and survive within host phagocytes ...
Phagocytosis is the process of taking in relatively large particles by a cell, and is a central mechanism in the tissue remodeling, inflammation, and defense against infectious agents. A phagosome is formed when the specific receptors on the phagocyte surface recognize ligands on the particle surface. After formation, nascent phagosomes progressively acquire digestive characteristics. This maturation of phagosomes involves regulated interaction with the other membrane organelles, including recycling endosomes, late endosomes and lysosomes. The fusion of phagosomes and lysosomes releases toxic products that kill most bacteria and degrade them into fragments. However, some bacteria have strategies to escape the bactericidal mechanisms associated with phagocytosis and survive within host phagocytes ...
This volume details experimental approaches used to investigate phagocytosis and phagosome maturation. Chapters present methods and protocols on quantifying uptake and phagosome maturation using bioph
Autophagy has been postulated to play role in mammalian host defense against fungal pathogens, although the molecular details remain unclear. Here, we show that primary macrophages deficient in the autophagic factor LC3 demonstrate diminished fungicidal activity but increased cytokine production in response to Candida albicans stimulation. LC3 recruitment to fungal phagosomes requires activation of the fungal pattern receptor dectin-1. LC3 recruitment to the phagosome also requires Syk signaling but is independent of all activity by Toll-like receptors and does not require the presence of the adaptor protein Card9. We further demonstrate that reactive oxygen species generation by NADPH oxidase is required for LC3 recruitment to the fungal phagosome. These observations directly link LC3 to the inflammatory pathway against C. albicans in macrophages.. ...
Here, we describe an approach to directly visualize the activity of proteases that are incorporated into the phagosome at different stages of maturation. Only small numbers of phagocytes are required and there is no need to isolate individual endosomal compartments before analysis. This method is sensitive enough to allow an examination of primary cultures of professional APC, including DCs. Furthermore, the use of covalent active site-directed probes in conjunction with electrophoresis ensures specificity. Methods that employ fluorogenic substrates to detect protease activity suffer from the drawback that more than one enzyme can usually cleave a given peptide substrate. Analysis of the delivery of active hydrolases to the phagosome helped clarify both the distribution of cysteine protease activities among the different endocytic organelles and the dynamics of phagosomal maturation in primary cultures of professional APCs.. We validated our method of in vivo labeling of phagosomal proteolytic ...
Innate immunity is vital for protection from microbes and is mediated by humoral effectors, such as cytokines, and cellular immune defenses, including phagocytic cells (e.g., macrophages). After internalization
Pathogens have evolved a range of mechanisms to counteract host defenses, notably to survive harsh acidic conditions in phagosomes. In the case of
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.
Tony Yeung, Bryan Heit, Jean-Francois Dubuisson, Gregory D. Fairn, Basil Chiu, Robert Inman, Andras Kapus, Michele Swanson, Sergio Grinstein ...
Serine/threonine MAP kinase; involved in regulating maintenance of cell wall integrity, progression through the cell cycle, and nuclear mRNA retention in heat shock; required for mitophagy and pexophagy; affects recruitment of mitochondria to the phagophore assembly site (PAS); regulated by the PKC1-mediated signaling pathway ...
p62/SQSTM1/Sequestosome-1 is an N-recognin of the N-end rule pathway which modulates autophagosome biogenesis / Hyunjoo Cha-Molstad; Ji-Eun Yu; Z Feng; S H Lee; Jung Gi Kim; P Yang; B Han; K W Sung; Y D Yoo; Joonsung Hwang; T McGuire; S M Shim; H D Song; S Ganipisetti; N Wang; J M Jang; M J Lee; Seung Jun Kim; Kyung Ho Lee; J T Hong; A Ciechanover; I Mook-Jung; K P Kim; X Q Xie; Y T Kwon; Bo Yeon Kim , 2017 ...
p62/SQSTM1/Sequestosome-1 is an N-recognin of the N-end rule pathway which modulates autophagosome biogenesis / Hyunjoo Cha-Molstad; Ji-Eun Yu; Z Feng; S H Lee; Jung Gi Kim; P Yang; B Han; K W Sung; Y D Yoo; Joonsung Hwang; T McGuire; S M Shim; H D Song; S Ganipisetti; N Wang; J M Jang; M J Lee; Seung Jun Kim; Kyung Ho Lee; J T Hong; A Ciechanover; I Mook-Jung; K P Kim; X Q Xie; Y T Kwon; Bo Yeon Kim , 2017 ...
Reactome is pathway database which provides intuitive bioinformatics tools for the visualisation, interpretation and analysis of pathway knowledge.
Reactome is pathway database which provides intuitive bioinformatics tools for the visualisation, interpretation and analysis of pathway knowledge.
Erwig LP, McPhilips KA, Wynes MW, Ivetic A, Ridley AJ, Henson PM. Differential regulation of phagosome maturation in macrophages and dendritic cells mediated by Rho GTPases and ezrin-radixin-moesin (ERM) proteins ...
UniProt ITasser SWISS Models alphafold D3Targets-2019-nCoV Plays a role in the initial induction of autophagosomes from host reticulum endoplasmic. Later, limits the expansion of these phagosomes that are no longer able to deliver viral components to lysosomes. ...
strong evidence that transcriptional repression plays a major role in regulating GARAPL1/MAP1LC3A levels, and this up-regulation results in an increase in the size of the autophagosome ...
Recently, the fixed-dose combinations (FDC) KIVEXA™ (abacavir/lamivudine) and TRUVADA (tenofovir disoproxil fumarate/emtricitabine) have facilitated the usage of once-daily regimens. However data from head-to-head randomized trials comparing these two FDCs as part of an initial regimen are not available at present. The long-term toxicity profiles of these regimens are of particular importance, as treatment of HIV is currently life-long and therefore, minimizing long-term toxicity and maximizing adherence and duration of regimen maintenance are critical therapy objectives.. The primary endpoint is estimated glomerular filtration rate (GFR), as measured by the modified diet in renal disease (MDRD) equation, a validated estimate of renal function. ...
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 ...
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]. 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 in ...
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.
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
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...
Phagocytosis (literally, cell eating) is a form of endocytosis where large particles are enveloped by the cell membrane of a (usually larger) cell and internalized to form a phagosome, or food vacuole. ... ...
Phagosome. A phagosome is a vacuole formed around a particle absorbed by phagocytosis. The vacuole is formed by the fusion of ... A phagosome is a cellular compartment in which pathogenic microorganisms can be killed and digested. Phagosomes fuse with ...
Phagosomes in macrophages: formation and structure. In: van Furth R, ed. Mononuclear Phagocytes in Immunity, Infection and ...
Diagrammatic representation of disc shedding and phagosome retrieval into the pigment epithelial cell "Archived copy". Archived ...
Deretic, V., & Fratti, R. A. (1999). Mycobacterium tuberculosis phagosome. Molecular microbiology, 31(6), 1603-1609. Chicago ... Mycobacterium tuberculosis inhibits phagosome-endosome fusion, thus avoiding being destroyed by the harsh environment of the ... phagosome. ICP47 from some herpesvirus block transport of the peptide by TAP. U21 from some human herpesvirus 7 binds and ...
Its cell wall prevents the fusion of the phagosome with the lysosome, which contains a host of antibacterial factors. ... The bacteria also carry the UreC gene, which prevents acidification of the phagosome. In addition, production of the diterpene ... "Mycobacterium tuberculosis releases an antacid that remodels phagosomes". Nature Chemical Biology. 15 (9): 889-99. doi:10.1038/ ... isotuberculosinol prevents maturation of the phagosome. The bacteria also evades macrophage-killing by neutralizing reactive ...
Lodge, R; Descoteaux, A (2008). Leishmania invasion and phagosome biogenesis. Subcellular Biochemistry. 47. pp. 174-81. doi: ...
Weber SM, Levitz SM, Harrison TS (August 2000). "Chloroquine and the fungal phagosome". Current Opinion in Microbiology. 3 (4 ...
They grow and multiply inside the phagosome. The macrophages travel in lymphatic circulation and can spread the disease to ... They survive inside the phagosome. As the fungus is thermally dimorphic, these microconidia are transformed into yeast. ... different organs.[citation needed] Within the phagosome, the fungus has an absolute requirement for thiamine. Cell-mediated ...
Alveolar macrophages phagocytize and destroy conidia within their phagosomes. Epithelial cells, specifically type II ...
But the ER- mitochondria contact site have markers, the auto-phagosome marker ATG14, and the auto-phagosome-formation marker ... Isolation membranes are the initial step to form auto-phagosomes. These closed membranes are double membrane-bond, with ... ATG5, until the formation of auto-phagosome is complete. Whereas, the absent of ATG14 puncta, it is caused by the breakdown of ...
"The Kinetics of Phagosome Maturation as a Function of Phagosome/Lysosome Fusion and Acquisition of Hydrolytic Activity". ... This happens during the step of acidification of phagosome before fusion with lysosome.[clarification needed] The escaped virus ... Kinchen, Jason M.; Ravichandran, Kodi S. (October 2008). "Phagosome maturation: going through the acid test". Nature Reviews. ...
Nunes P, Guido D, Demaurex N (December 2015). "Measuring Phagosome pH by Ratiometric Fluorescence Microscopy". Journal of ...
"Lysosomal enzyme trafficking between phagosomes, endosomes, and lysosomes in J774 macrophages. Enrichment of cathepsin H in ...
Localization to the phagosome and activation by polyphosphoinositides". J. Biol. Chem. 277 (4): 2620-8. doi:10.1074/jbc. ...
2001). "The phagosome proteome: insight into phagosome functions". J. Cell Biol. 152 (1): 165-80. doi:10.1083/jcb.152.1.165. ...
Murray RZ, Kay JG, Sangermani DG, Stow JL (December 2005). "A role for the phagosome in cytokine secretion". Science. 310 (5753 ... Phagocytosis and Phagosomes, Springer New York, 1519, pp. 201-214, doi:10.1007/978-1-4939-6581-6_13, ISBN 9781493965793, PMID ...
a. Ingestion through phagocytosis, a phagosome is formed. b. The fusion of lysosomes with the phagosome; the pathogen is broken ... 2. Phagosome. 3. Lysosomes. 4. Waste material. 5. Cytoplasm. 6. Cell membrane ...
Ferrari G, Langen H, Naito M, Pieters J (May 1999). "A coat protein on phagosomes involved in the intracellular survival of ... this resulting in a stop of fusion lysosomes with phagosomes. In other words, if coronin-1a is removed and calcinuerin is ... inhibited then it allows the initiation of the fusion of phagosomes with lysosome and the killing of mycobacteria. The ...
Neefjes further expanded his work on endosomes to phagosomes and intracellular bacteria. By combining chemistry, cell biology ...
ATG13 is an autophagy factor required for phagosome formation. ATG13 is a target of the TOR kinase signaling pathway that ...
The phagosome is the organelle formed by phagocytosis of material. It then moves toward the centrosome of the phagocyte and is ... The ingested material is then digested in the phagosome. Bacteria, dead tissue cells, and small mineral particles are all ... As in phagocytic immune cells, the resulting phagosome may be merged with lysosomes(food vacuoles) containing digestive enzymes ... Degranulation of these into the phagosome, accompanied by high reactive oxygen species production (oxidative burst) is highly ...
Hampton MB, Kettle AJ, Winterbourn CC (November 1998). "Inside the neutrophil phagosome: oxidants, myeloperoxidase, and ... which transfers electrons from cytosolic NADPH to O2 in the phagosome. 2O2 + NADPH -> 2O2•- + NADP+ + H+ The superoxide can ...
Hampton MB, Kettle AJ, Winterbourn CC (Nov 1998). "Inside the neutrophil phagosome: oxidants, myeloperoxidase, and bacterial ...
... acidificiation of phagosomes, and fusion of the phagosome and lysosome. B. suis, in return, has developed ways to counteract ... Lipid rafts on phagosomes prevent lysosomal fusion, and normal cell trafficking is unaffected. The most frequent clinical sign ... Once inside macrophages, B. suis is able to endure the rapid acidificiation in the phagosome to pH 4.0-4.5 by expressing ... The phagosome rapidly acidifies, creating a stressful environment for bacteria, which triggers activation of virulence genes. ...
"The effect of light on the quantity of phagosomes in the pigment epithelium". Experimental Eye Research. 23 (6): 623-35. doi: ...
Jamwal SV, Mehrotra P, Singh A, Siddiqui Z, Basu A, Rao KV (March 2016). "Mycobacterial escape from macrophage phagosomes to ...
"Imaging of Rab5 activity identifies essential regulators for phagosome maturation". Nature. 453 (7192): 241-5. doi:10.1038/ ...
Tuberculosis toxin blocking phagosome maturation inhibits a novel Ca2!/calmodulin-PI3K hVPS34 cascade. J. Exp. Med. 198:653-659 ... Role of phosphatidylinositol 3-kinase and Rab5 effectors in phagosomal biogenesis and mycobacterial phagosome maturation arrest ... Mycobacterium tuberculosis phagosome maturation arrest: mycobacterial phosphatidylinositol analog phosphatidylinositol ...
2005). "Rab coupling protein associates with phagosomes and regulates recycling from the phagosomal compartment". Traffic. 5 ( ...
... through cooperation with phagosomes, they are able to conduct autophagy, clearing out damaged structures. Similarly, they are ...
Retrieved from "https://en.wiktionary.org/w/index.php?title=phagosome&oldid=47629103" ...
... a membrane-bound vacuole called a phagosome. The phagocyte digests the ingested particle with hydrolytic enzymes, which are ... Other articles where Phagosome is discussed: phagocytosis: Particle engulfment and digestion: … ... a membrane-bound vacuole called a phagosome. The phagocyte digests the ingested particle with hydrolytic enzymes, which are ...
Chapters present methods and protocols on quantifying uptake and phagosome maturation using bioph ... This volume details experimental approaches used to investigate phagocytosis and phagosome maturation. ... Isolation and Western Blotting of Latex-Bead Phagosomes to Track Phagosome Maturation ... Authoritative and cutting-edge, Phagocytosis and Phagosomes: Methods and Protocols aims to be an important resource for both ...
The phagosome then undergoes a maturation process whereby it transforms into a phagolysosome. Phagosome maturation depends on ... Phagosome dynamics and function.. Tjelle TE1, Lovdal T, Berg T.. Author information. 1. Norwegian Radium Hospital, Department ... receptors and ligands on the particle results in signal transduction events that lead to actin polymerisation and phagosome ...
This means a phagosome is several orders of magnitude bigger than an endosome, which is measured in nanometres. Phagosomes are ... Early phagosomes are characterised by Rab5, which transition into Rab7 as the vesicle matures into late phagosomes. The nascent ... Rab5 is present on early phagosomes, and controls the transition to late phagosomes marked by Rab7. Rab5 recruits PI-3 kinase ... Such incomplete maturation of the phagosome maintains an environment favorable to the pathogens inside it . Phagosomes are ...
Phagosomes containing S. typhimurium required 4-5 hr to reach pH , 5.0. In contrast, within 1 hr vacuoles containing heat- ... Salmonella typhimurium activates virulence gene transcription within acidified macrophage phagosomes. C M Alpuche Aranda, J A ... Salmonella typhimurium activates virulence gene transcription within acidified macrophage phagosomes. C M Alpuche Aranda, J A ... These observations implicate phagosome acidification as an intracellular inducer of PhoP-regulated gene expression and suggest ...
... particularly within the macrophage phagosome compartment. The phagosome compartment is a nutrient-limited environment, ... requiring Histoplasma yeasts to be able to assimilate available carbon sources within the phagosome to meet their nutritional ...
Early phagosomes are characterised by Rab5, which transition into Rab7 as the vesicle matures into late phagosomes. ... Rab5 is present on early phagosomes, and controls the transition to late phagosomes marked by Rab7.[18] ... They either reproduce inside of the phagolysosome (e.g. Coxiella spp.)[1] or escape into the cytoplasm before the phagosome ... Roy, Craig R.; Kagan, Jonathan C. (1 January 2013). Evasion of Phagosome Lysosome Fusion and Establishment of a Replicative ...
phagosome - OneLook Dictionary Search. Tip: Click on the first link on a line below to go directly to a page where "phagosome" ... Phagosome - Wikipedia, the free encyclopedia. In cell biology, a phagosome is a vacuole formed around a particle absorbed by ... fusion of phagosomes with lysosomes is precluded by wortmannin, with phagosomes or the clathrin-mediated endocytosis of ... Interestingly as in mouse phagosomes, a subset of heterotrimeric The phagosomes analyzed in gel A are a pool of the early three ...
Disease relevance of Phagosomes. *Here we show that Toll-like receptor 2 is recruited specifically to macrophage phagosomes ... Gene context of Phagosomes. *The Toll-like receptor 2 is recruited to macrophage phagosomes and discriminates between pathogens ... Natural resistance to infection with intracellular pathogens: the Nramp1 protein is recruited to the membrane of the phagosome. ... Cholesterol depletion in Mycobacterium avium-infected macrophages overcomes the block in phagosome maturation and leads to the ...
... belongs to a group of highly virulent intracellular parasites that reside in host cell vacuoles which resist typical phagosome- ... Phagosome acidification blocked by intracellular Toxoplasma gondii Nature. 1985 May 30-Jun 5;315(6018):416-9. doi: 10.1038/ ... In contrast, when live Toxoplasma are coated with specific antibody (heat-inactivated), they trigger phagosome acidification ... Of newly recognized significance to Toxoplasma survival is the microbicidal effect of phagosome acidification, which reportedly ...
After formation, nascent phagosomes progressively acquire digestive characteristics. This maturation of phagosomes involves ... Phagosome - Parastagonospora nodorum [ Pathway menu , Organism menu , Pathway entry , Download KGML , Show description , User ... The fusion of phagosomes and lysosomes releases toxic products that kill most bacteria and degrade them into fragments. However ... A phagosome is formed when the specific receptors on the phagocyte surface recognize ligands on the particle surface. ...
CFTR regulates phagosome acidification in macrophages and alters bactericidal activity.. Di A1, Brown ME, Deriy LV, Li C, Szeto ... Acidification of phagosomes has been proposed to have a key role in the microbicidal function of phagocytes. Here, we show that ... although they retained normal fusogenic capacity with nascent phagosomes. We hypothesize that CFTR contributes to lysosomal ...
... or on phagosomes containing ΔralFmutants (3.7 ± 3.6%). Thus, localization of RalF protein on phagosomes containing L. ... ARF1-GFP co-localization was observed on phagosomes containing wild-type L. pneumophila but was not detected on phagosomes ... A Bacterial Guanine Nucleotide Exchange Factor Activates ARF on Legionella Phagosomes. By Hiroki Nagai, Jonathan C. Kagan, ... A Bacterial Guanine Nucleotide Exchange Factor Activates ARF on Legionella Phagosomes. By Hiroki Nagai, Jonathan C. Kagan, ...
phagosome: A membrane-bound vesicle found in a cell by an inward folding of the cell membrane to hold foreign matter taken into ... The team identified ten distinct mutants, only one of which had previously been shown to play a part in phagosome maturation ... Based on the results, it was hypothesized that the phagosome environment and vacuole membrane of the wild-type bacterium might ... Urease activity which was shown to be critical for M. tuberculosis survival in phagosome is dependent on Nickel, while Vitamin ...
A phagosome is a cellular compartment in which pathogenic microorganisms can be killed and digested. Phagosomes fuse with ... In cell biology, a phagosome is a vacuole formed around a particle absorbed by phagocytosis. The vacuole is formed by the ... Retrieved from "https://www.wikidoc.org/index.php?title=Phagosome&oldid=252255" ...
... coli phagosomes observed in Drosophila hemocytes was consistent with that previously described for phagosome maturation in ... In wild-type females, E. coli were detected within enlarged Rab7-GFP positive phagosomes at 15 to 45 minutes after infection; ... We also tested our model as a tool for genetic analysis using 14-3-3e mutants, and demonstrated altered phagosome maturation ... The degradative properties of phagosomes are thought to be conferred by sequential fusion with endosomes and lysosomes; however ...
show that EFF-1 fusogen generates a sealed phagosome during engulfment of cells with long processes in Caenorhabditis elegans, ... EFF-1 localizes to phagocyte pseudopod tips and acts exoplasmically to drive phagosome sealing. eff-1 mutations result in ... Our studies suggest universal mechanisms for dismantling morphologically complex cells and uncover a phagosome-sealing ... proteins that directly mediate phagosome sealing are uncharacterized. Furthermore, whether all phagocytic targets are cleared ...
... Nat Cell Biol. 2008 May;10(5):556-66. doi: 10.1038/ ... with DYN-1 functioning upstream of VPS-34 in the recruitment and/or retention of RAB-5 to the phagosome. Finally, we have also ... into a coherent linear pathway for the maturation of apoptotic cells within phagosomes. In depth analysis of two additional ... we have identified genes required for maturation of apoptotic-cell-containing phagosomes. We have further ordered these ...
Phagosome : Drug Discovery and Development [home, info]. The kinetics of phagosome maturation as a function of phagosome/ ... The kinetics of phagosome maturation as a function of phagosome/lysosome fusion and acquisition of hydrolytic activity. ... phagosome - OneLook Dictionary Search (125 words). Tip: Click on the first link on a line below to go directly to a page where ... Encyclopedia , Phagosome. In cell biology, a vacuole formed around a particle absorbed by phagocytosis. The vacuole is formed ...
LC3 recruitment to fungal phagosomes requires activation of the fungal pattern receptor dectin-1. LC3 recruitment to the ... Dectin-1-dependent LC3 recruitment to phagosomes enhances fungicidal activity in macrophages.. ... Phagosomes, Phosphorylation, Protein-Tyrosine Kinases, Reactive Oxygen Species, Signal Transduction, Syk Kinase, Tumor Necrosis ... phagosome also requires Syk signaling but is independent of all activity by Toll-like receptors and does not require the ...
These findings show that inhibition of phagosome acidification in the mycobacterial phagosome is directly attributed to PtpA, a ... associates with V-ATPase in phagosome maturation, suggesting a unique role for V-ATPase in coordinating phagosome-lysosome ... Mycobacterium tuberculosis protein tyrosine phosphatase (PtpA) excludes host vacuolar-H+-ATPase to inhibit phagosome ... Mycobacterium tuberculosis protein tyrosine phosphatase (PtpA) excludes host vacuolar-H+-ATPase to inhibit phagosome ...
HVEM Observation of Phagosome-Lysosome Fusion in the Pigment Epithelium * * SAITO Takuma ... Interference with normal phagosome-lysosome fusion in macrophages, using ingested yeast cells and suramin HART DP ... From this study, the contents of the lysosome pored into the phagosome through the orifice, shortly after the collision of the ... The hydrolytic enzymes such as acid phosphatase spread in a sheet under the limiting membrane of the phagosome to finally form ...
Phagosome-regulated mTOR signalling during sarcoidosis granuloma biogenesis. Elliott D. Crouser, Landon W. Locke, Mark W. ... Phagosome-regulated mTOR signalling during sarcoidosis granuloma biogenesis. Elliott D. Crouser, Landon W. Locke, Mark W. ... Phagosome-regulated mTOR signalling during sarcoidosis granuloma biogenesis. Elliott D. Crouser, Landon W. Locke, Mark W. ... Phagosome-regulated mTOR signalling during sarcoidosis granuloma biogenesis Message Subject (Your Name) has sent you a message ...
Autophagy proteins stabilize pathogen-containing phagosomes for prolonged MHC II antigen processing. Susana Romao, Nathalie ... Autophagy proteins stabilize pathogen-containing phagosomes for prolonged MHC II antigen processing ...
Wild type (WT) H. pylori exhibited more delayed entry into macrophages and also arrested phagosome maturation more than did ... Cholesterol glucosylation by H. pylori interferes with phagosome trafficking via a lipid-raft and PI3K-dependent manner, which ... Cholesterol glucosylation by Helicobacter pylori delays internalization and arrests phagosome maturation in macrophages.. [Shin ...
We describe a cell-free scintillation proximity assay developed to study the mechanisms of lysosome targeting to phagosomes and ... The approach involves the use of isolated phagosomes containing scintillant latex beads and lysosomes labeled with a tritiated ... Scintillation results only when lysosomes and phagosomes come into immediate contact and requires supplementation of reactions ... A Cell-Free Scintillation Proximity Assay for Studies on Lysosome-to-Phagosome Targeting ...
Cryptococci are shown to be able to manipulate the phagosome they reside within. This is driven by modified acquisition of Rab ... Smith, Leanne May (2015). Investigating phagosome dynamics of microbial pathogens. University of Birmingham. Ph.D. ... Furthermore, by investigating the \(Streptococcus\)-containing phagosome, it was revealed that streptococci are able to ... GTPases to the phagosome, as well as altered acidification and cathepsin activity within \(Cryptococcus\)-containing phagosomes ...
... the molecular mechanisms of how the digestive enzymes are transported to phagosomes. Understanding of such mechanisms of the ... Author Summary Phagocytosis is the cellular process of engulfing solid particles to form an internal phagosome in protozoa, ... Phagosomes Is the Subject Area "Phagosomes" applicable to this article? Yes. No. ...
In contrast to phagosomes containing live bacteria, the majority of phagosomes containing formalin-killed L. pneumophila were ... Phagosomes containing live L. pneumophila did not fuse with secondary lysosomes at 1 h after entry into monocytes or at 4 or 8 ... The capacity of L. pneumophila to inhibit phagosome-lysosome fusion may be a critical mechanism by which the bacterium resists ... The Legionnaires disease bacterium (Legionella pneumophila) inhibits phagosome-lysosome fusion in human monocytes.. M A ...
  • Phagosome Extrusion and Host-Cell Survival after Cryptococcus neoformans Phagocytosis by Macrophages. (factbites.com)
  • After uptake of bacteria by macrophages, phagosomes rapidly fuse with lysosomes (within 30 minutes) to become phagolysosomes, in which bacteria are degraded. (factbites.com)
  • To explore the role of TLR signalling in the regulation of this phagosome-maturation pathway, the authors followed the uptake of fluorescent bacteria by wild-type macrophages or those that lacked expression of TLR2 and TLR4, or MyD88 - a crucial TLR-signalling adaptor protein. (factbites.com)
  • In contrast, when live Toxoplasma are coated with specific antibody (heat-inactivated), they trigger phagosome acidification when entering normal macrophages. (nih.gov)
  • CFTR regulates phagosome acidification in macrophages and alters bactericidal activity. (nih.gov)
  • Lysosomes from CFTR-null macrophages failed to acidify, although they retained normal fusogenic capacity with nascent phagosomes. (nih.gov)
  • The environment in the phagosome of macrophages infected with the mutant differed from the environment of vacuoles with M. hominissuis wild-type in the concentration of zinc, manganese, calcium and potassium. (wordnik.com)
  • This mutant, in contrast to the wild-type bacterium, was shown both to have impaired the ability to replicate within macrophages and to have prevented phagosome /lysosome fusion. (wordnik.com)
  • We employed Drosophila hemocytes, which are similar to mammalian professional macrophages, to establish a model of phagosome maturation. (mdpi.com)
  • The interaction of endosomes and lysosomes with E. coli phagosomes observed in Drosophila hemocytes was consistent with that previously described for phagosome maturation in human ex vivo macrophages. (mdpi.com)
  • Dectin-1-dependent LC3 recruitment to phagosomes enhances fungicidal activity in macrophages. (broadinstitute.org)
  • Mycobacterium tuberculosis (Mtb) pathogenicity depends on its ability to inhibit phagosome acidification and maturation processes after engulfment by macrophages. (pnas.org)
  • These findings show that inhibition of phagosome acidification in the mycobacterial phagosome is directly attributed to PtpA, a key protein needed for Mtb survival and pathogenicity within host macrophages. (pnas.org)
  • Cholesterol glucosylation by Helicobacter pylori delays internalization and arrests phagosome maturation in macrophages. (sigmaaldrich.com)
  • Wild type (WT) H. pylori exhibited more delayed entry into macrophages and also arrested phagosome maturation more than did capJ knockout mutant. (sigmaaldrich.com)
  • Acidification of phagosomes containing Salmonella typhimurium in murine macrophages. (asm.org)
  • The influence of phorbol myristic acetate on the formation of pseudopodia and phagosomes of macrophages. (unikom.ac.id)
  • Here we visualize host-pathogen interactions using live-cell imaging and show that viable, but not heat- or UV-killed C. albicans cells profoundly delay phagosome maturation in macrophage cell lines and primary macrophages. (asm.org)
  • We used live-cell microscopy and fluorescent protein reporter macrophages to understand how C. albicans viability, filamentous growth, and cell wall composition affect phagosome maturation and the survival of the pathogen within host macrophages. (asm.org)
  • As T. whipplei is detected in PAS-positive inclusions inside macrophages, its intracellular survival is likely related to subversion of phagosome maturation. (asm.org)
  • Stereological analysis of transmission electron micrographs was used to investigate the kinetics of the intracellular life cycle of F.t.n., the effects of IFNγ-activation of macrophages, and the inhibition of lysosomal proteases on the ability of F.t.n. to escape from the phagosome. (uio.no)
  • Lysosomal enzyme trafficking between phagosomes, endosomes, and lysosomes in J774 macrophages. (semanticscholar.org)
  • In this study we take advantage of recently developed methods using J774 macrophages to prepare enriched fractions of early endosomes, late endosomes, dense lysosomes, as well as phagosomes of different ages enclosing 1-micron latex beads to investigate the steady state distribution and trafficking of lysosomal enzyme activity between these organelles. (semanticscholar.org)
  • To test this presumption, fluorescent protein chimeras were expressed in RAW 264.7 macrophages, and time-lapse ratiometric fluorescence microscopy was used to measure the maturation dynamics of individual phagosomes containing IgG-opsonized erythrocytes. (rupress.org)
  • Here we have characterised the critical degradative process of phagosome maturation in primary human macrophages for five genotypically and phenotypically distinct clinical strains of H. pylori . (biomedcentral.com)
  • H. pylori appeared to disrupt the normal process of phagosome maturation in primary human macrophages, appearing to block endosome fission. (biomedcentral.com)
  • Although the mechanism that H. pylori employs to avoid phagocytic killing is not completely understood, some disruptions to the normal process of phagosome maturation have been noted in H. pylori -infected macrophages. (biomedcentral.com)
  • Kielian, MC & Cohn, ZA 1980, ' Phagosome-lysosome fusion: Characterization of intracellular membrane fusion in mouse macrophages ', Journal of Cell Biology , vol. 85, no. 3, pp. 754-765. (elsevier.com)
  • Most knowledge regarding the maturation of a nascent phagosome into an antimicrobial phagosome comes from the study of macrophages. (biomedcentral.com)
  • In macrophages, Syt V is localized on recycling endosomes and on filopodia-like structures and is recruited to the nascent phagosomes independently of the phagocytic receptor engaged. (jimmunol.org)
  • In contrast, silencing of Syt V had no effect on the recruitment of the lysosomal marker LAMP1 to phagosomes, indicating that phagosome maturation is not regulated by Syt V. Collectively, these results illustrate the importance of Syt V in the regulation of an important innate function of macrophages. (jimmunol.org)
  • Vieira, MOV 2014, MATURATION OF PHAGOSOMES-CONTAINING DIFFERENT PARTICLES IN MURINE PRIMARY MACROPHAGES . (unl.pt)
  • Phagosomes in Stat1-/- macrophages showed normal maturation as judged by the accumulation of the lysosomal marker protein rab7, and provided normal vATPase activity, but were defective in the anion conductive pathway required for full vesicular acidification. (pasteur.fr)
  • Isolation of F. novicida-Containing Phagosome from Infected Human Monocyte Derived Macrophages. (helmholtz-hzi.de)
  • To survive this attack by macrophages, C. albicans generates energy by utilizing alternative carbon sources that are available in the phagosome. (cloudfront.net)
  • One major macrophage function altered by cytokine activation is phagocytosis and phagosome maturation, through which macrophages engulf foreign material such as microbes or apoptotic cells to form phagosomes which then fuse with endosome and finally lysosomes, where the particles are finally degraded. (dundee.ac.uk)
  • My project aims at investigating the phagosome functions regulated in activated macrophages and further exploring the mechanism by which alternative activation regulates phagosome biogenesis. (dundee.ac.uk)
  • Phagosomes are highly dynamic organelles formed by the uptake of particles through phagocytic innate immune cells such as macrophages. (tees.ac.uk)
  • Here, we have performed an in-depth proteomics characterisation of phagosomes from RAW 264.7 and bone marrow-derived macrophages by quantifying more than 2500 phagosomal proteins. (dundee.ac.uk)
  • Pathogenic mycobacteria escape host innate immune responses by surviving within phagosomes of host macrophages and blocking their delivery to lysosomes. (unibas.ch)
  • These observations implicate phagosome acidification as an intracellular inducer of PhoP-regulated gene expression and suggest that Salmonella survival is dependent on its ability to attenuate phagosome acidification. (pnas.org)
  • Early escape from the phagosome vacuole is essential for growth and virulence of some intracellular pathogens. (factbites.com)
  • Toxoplasma gondii belongs to a group of highly virulent intracellular parasites that reside in host cell vacuoles which resist typical phagosome-lysosome fusion. (nih.gov)
  • 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. (mdpi.com)
  • Cholesterol glucosylation by H. pylori interferes with phagosome trafficking via a lipid-raft and PI3K-dependent manner, which retards engulfment of bacteria for prolonged intracellular survival of H. pylori. (sigmaaldrich.com)
  • Erythromycin, a potent inhibitor of bacterial protein synthesis, at a concentration that completely inhibits L. pneumophila intracellular multiplication, had no influence on fusion of L. pneumophila phagosomes with secondary lysosomes. (rupress.org)
  • SNX3 thus forms a hub for two distinct vesicle populations, constituting a convergence point for the endosomal recycling machinery, to contribute to phagosome maturation and intracellular processing of borreliae. (medworm.com)
  • Phagosomes are the membrane bound intracellular vesicle which contain phagocytozed material. (unikom.ac.id)
  • LPC also promoted phagosome maturation via phosphatidylinositol 3 kinase (PI3K)-p38 mitogen-activated protein kinase (MAPK)-mediated reactive oxygen species production and intracellular Ca 2+ release during Mtb infection. (frontiersin.org)
  • Live Mtb induces low levels of cytosolic Ca 2+ release, which is correlated with inhibition of phagosome-lysosome fusion, suggesting that Ca 2+ -induced intracellular signaling pathways contribute to the intracellular pathogen survival and pathogenesis of TB ( 6 , 7 ). (frontiersin.org)
  • Phagosomes are intracellular organelles in dendritic cells in which pathogens such as viruses, bacteria and parasites are internalised to be proteolysed and killed. (bio-protocol.org)
  • Fransicella tularensis (F.t.) is a facultative intracellular pathogen that escapes from the phagosome into the host cell cytosol in order to survive and proliferate. (uio.no)
  • Our study showed that the bacterial load in RAW 264.7 was several folds higher compared to BMM, which argues that RAW 264.7 cells support the intracellular proliferation of F.t.n. better than BMM, which were very susceptible to the induction of cell death (pyroptosis) when bacteria escaped from the phagosome into the cytosol of the host cell. (uio.no)
  • There were also strain specific differences in the timing of Rab7 acquisition which correlated with differences in the rate of intracellular trafficking of phagosomes and the timing of megasome formation. (biomedcentral.com)
  • 2002). Notably, several intracellular pathogens disrupt phagosome transport to survive in a latent form inside cells (Harrison et al . (bio-protocol.org)
  • Phagosome formation is crucial for tissue homeostasis and both innate and adaptive host defense against pathogens. (wikipedia.org)
  • Phagosomes are formed when pathogens or opsonins bind to a transmembrane receptor, which are randomly distributed on the phagocyte cell surface. (wikipedia.org)
  • A number of pathogens, including C. albicans , have evolved mechanisms that attenuate the efficiency of phagosome-mediated inactivation, promoting their survival and replication within the host. (asm.org)
  • The methods employed here are applicable to study interactions of other pathogens with phagocytic cells to dissect how specific microbial features impact different stages of phagosome maturation and the survival of the pathogen or host. (asm.org)
  • One such process is phagosome maturation, which is involved in degradation of pathogens taken up by macrophage cells of the immune system, and is also used as a process of nutrition in lower eukaryotes (Vieira et al . (bio-protocol.org)
  • 2007). Therefore, reconstitution of phagosome transport might help to understand the strategy used by pathogens for immune evasion. (bio-protocol.org)
  • To improve the understanding of such events, like phagosome maturation, we set out to develop a versatile technique for phagosome isolation that is rapid and widely applicable to different pathogens. (biomedcentral.com)
  • These findings appear relevant to several pathogens that prevent phagosome-lysosome fusion by targeting lipid microdomains on phagosomes. (ccamp.res.in)
  • a membrane-bound vacuole called a phagosome. (britannica.com)
  • Based on the results, it was hypothesized that the phagosome environment and vacuole membrane of the wild-type bacterium might differ from the mutant. (wordnik.com)
  • Phagocytosis (literally, cell eating) is a form of endocytosis where large particles are enveloped by the cell membrane of a (usually larger) cell and internalized to form a phagosome, or food vacuole. (statemaster.com)
  • Phagosomes containing live L. pneumophila did not fuse with secondary lysosomes at 1 h after entry into monocytes or at 4 or 8 h after entry by which time the ribosome-lined L. pneumophila replicative vacuole had formed. (rupress.org)
  • these organisms may share a common mechanism for vacuole formation and inhibition of phagosome-lysosome fusion. (rupress.org)
  • During internalization, target particles are surrounded by pseudopods and are engulfed in a vacuole, the phagosome, which rapidly matures into a microbicidal phagolysosome. (jimmunol.org)
  • In contrast, when M. tuberculosis is phagocytosed, the maturation of the bacteria-containing phagosome is arrested, and the bacterium resides within a vacuole that retains characteristics of early endosomal compartments. (elsevier.com)
  • The nascent phagosome is not inherently bactericidal. (wikipedia.org)
  • TRPV2 was recruited to the nascent phagosome and depolarized the plasma membrane. (wordnik.com)
  • Finally, we have also identified a previously undescribed biochemical complex containing Vps34, dynamin and Rab5(GDP), thus providing a mechanism for Rab5 recruitment to the nascent phagosome. (nih.gov)
  • Whereas the nascent phagosome is formed to a large extent by invagination of the plasma membrane ( 3 ), the membrane surface required to internalize multiple or large targets may represent an area equivalent to the entire cell surface ( 4 ). (jimmunol.org)
  • or escape into the cytoplasm before the phagosome fuses with the lysosome (e.g. (wikipedia.org)
  • The kinetics of phagosome maturation as a function of phagosome/lysosome fusion and acquisition of hydrolytic activity. (factbites.com)
  • Furthermore, we show that the macrophage class C vacuolar protein sorting complex, a key regulator of endosomal membrane fusion, associates with V-ATPase in phagosome maturation, suggesting a unique role for V-ATPase in coordinating phagosome-lysosome fusion. (pnas.org)
  • From this study, the contents of the lysosome pored into the phagosome through the orifice, shortly after the collision of the two organelles. (nii.ac.jp)
  • We describe a cell-free scintillation proximity assay developed to study the mechanisms of lysosome targeting to phagosomes and the regulation of this process by IgG. (sciencemag.org)
  • The method is useful for investigating the biochemistry and regulation of the early tethering and docking steps of lysosome and phagosome interactions. (sciencemag.org)
  • The Legionnaires' disease bacterium (Legionella pneumophila) inhibits phagosome-lysosome fusion in human monocytes. (rupress.org)
  • The capacity of L. pneumophila to inhibit phagosome-lysosome fusion may be a critical mechanism by which the bacterium resists monocyte microbicidal effects. (rupress.org)
  • However, Mtb has several mechanisms to evade host immune responses, such as phagosome-lysosome fusion interference, inhibition of phagosome acidification, inflammatory immune suppression, and host cell death modulation ( 5 ). (frontiersin.org)
  • The ability of T. whipplei to survive in an acidic environment and to interfere with phagosome-lysosome fusion is likely critical for its prolonged persistence in host cells during the course of Whipple's disease. (asm.org)
  • Early phagosomes rapidly and transiently acquire markers of early endocytosis and then markers of late endocytosis, including the lysosome-associated membrane protein (Lamp-1) and the vacuolar proton ATPase (V-ATPase) responsible for acidic pH. (asm.org)
  • Phagosomes are formed by fusion with the plasma membrane, some area of the endoplasmic reticulum as well as the lysosome. (bio-protocol.org)
  • Inhibition of phagosome-lysosome fusion in ovine polymorphonuclear leucocytes by Ehrlichia (Cytoecetes) phagocytophila. (semanticscholar.org)
  • The early endosome marker EEA1 and late endosome marker Rab7 were retained on H. pylori phagosomes, while the late endosome-lysosome markers CD63, LAMP-1 and LAMP-2 were acquired in an apparently normal manner. (biomedcentral.com)
  • This resulted in the formation of a hybrid phagosome-endosome-lysosome compartment, which we propose has reduced degradative capacity. (biomedcentral.com)
  • Moreover, BMDM phagosomes mature considerably faster by fusion with endosomes and the lysosome when validated using fluorogenic phagocytic assays. (dundee.ac.uk)
  • They control actin polymerisation which is required for the phagosome to fuse with endosomes and lysosomes. (wikipedia.org)
  • Interaction between these receptors and ligands on the particle results in signal transduction events that lead to actin polymerisation and phagosome formation. (nih.gov)
  • Loss of cell wall O -mannan is associated with enhanced acquisition of phagosome maturation markers, distinct changes in Rab GTPase acquisition by the maturing phagosome, impaired hyphal growth within macrophage phagosomes, profound changes in macrophage actin dynamics, and ultimately a reduced ability of fungal cells to escape from macrophage phagosomes. (asm.org)
  • The mechanism and role of transient F-actin recruitment or F-actin "flashes" on phagosomes remains enigmatic. (biologists.org)
  • Here we provide a comprehensive characterization of F-actin flashing dynamics on phagosomes including receptor and signaling involvement. (biologists.org)
  • F-actin flashes begin shortly after internalization and persist on phagosomes for ∼3 minutes before disassembling and reassembling several times within the first hour. (biologists.org)
  • Strikingly, the appearance of F-actin flashes on phagosomes coincides with RBC morphological deformation, lysis and occasional fission events. (biologists.org)
  • The cadence of flashes depends on particle stiffness and the F-actin networks on phagosomes are enriched in mechanosensitive components including focal adhesion proteins, RhoA and actomyosin. (biologists.org)
  • Inhibiting Arp2/3 and myosin IIA activity significantly reduces the frequency at which phagosome cargo becomes deformed during transient F-actin accumulation. (biologists.org)
  • At later time points, post-F-actin flashing, an enhanced degradation of phagosome contents is observed, compared to non-flashing phagosomes. (biologists.org)
  • Phagosome formation and subsequent maturation are complex sequences of events that involve actin cytoskeleton remodeling and membrane trafficking. (biologists.org)
  • It is likely that Rab35 regulates actin‐dependent phagosome formation by recruiting ACAP2, which might control actin remodeling and membrane traffic through ARF6. (biologists.org)
  • In the current study annexin A1 was identified as a factor, which binds to latex beads phagosomes (LBP) and facilitates F-actin-LBP interaction in vitro. (uni-rostock.de)
  • Phagosome-associated protein extracts contained cytoskeletal proteins actin and tubulin and proteins involved in trafficking along actin microfilaments (e.g. (arvojournals.org)
  • We found that phagosomes formed by engagement of integrins that serve as complement receptors (CR3) undergo secondary waves of actin polymerization, leading to the formation of "comet tails" that propel the vacuoles inside the cells. (elsevier.com)
  • Uptake is mediated in part by Syk, which may activate actin rearrangement in the phagocytic cup resulting in the engulfment of F. tularensis in a lipid raft rich phagosome. (frontiersin.org)
  • The acidification of phagosomes was significantly inhibited by a myosin inhibitor, whereas it was only marginally inhibited by microtubules or actin inhibitors. (elsevier.com)
  • By using genetic, pharmacological and proteomics approaches, we show that LRRK2 kinase activity negatively regulates phagosome maturation via the recruitment of the Class III phosphatidylinositol-3 kinase c. (ox.ac.uk)
  • Survival of Salmonella typhimurium within macrophage phagosomes requires the coordinate expression of bacterial gene products. (pnas.org)
  • In contrast, no difference in PhoP-activated gene expression was observed after infection of cultured epithelial cells, suggesting that the membrane sensor PhoQ recognized signals unique to macrophage phagosomes. (pnas.org)
  • Furthermore, by investigating the \(Streptococcus\)-containing phagosome, it was revealed that streptococci are able to manipulate the acidification of macrophage phagosomes. (bham.ac.uk)
  • 1,3-glucan FLP were used to analyze purified macrophage phagosomes. (grantome.com)
  • They may grow in the phagosome and release substances which can pass through the phagosome membrane and cause discharge of lysosomal granules, or they may grow in the phagolysosome and release toxic substances which pass through the phagolysosome membrane to other target sites in the cell. (factbites.com)
  • Ultrastructural changes, which may occur in the absence of lysosomal enzymes, were examined in phagosomes that were, on the basis of several criteria, undegraded. (arvojournals.org)
  • In the present study, the possible fusion of lysosomes with phagosomes containing E. phagocytophila was investigated in poly-morphonuclear (PMN) cells of sheep infected with the agent, acid phosphatase cytochemistry and cationized ferritin being used as markers of primary and secondary lysosomal enzymes. (semanticscholar.org)
  • In this regard, a recent study revealed that consistent with its role as a regulator of lysosomal exocytosis ( 14 , 15 , 16 ), Syt VII plays a key role in the delivery of lysosomal membrane to the phagosome ( 17 ), possibly acting in concert with VAMP7 ( 8 ). (jimmunol.org)
  • The nanoparticles co-localized with M.tb containing phagosomes, as measured by detection of mature cathepsin D 34 kDa, lysosomal hydrogenase. (duhnnae.com)
  • A phagosome containing an IgG-coated bead matures into a lysosomal compartment as evidenced by a decrease in pH and an increased acquisition of hydrolytic enzymes. (elsevier.com)
  • We describe a protocol to purify latex bead phagosomes (LBPs) from Dictyostelium cells. (bio-protocol.org)
  • Many Mycobacteria, including Mycobacterium tuberculosis and Mycobacterium avium paratuberculosis , can manipulate the host macrophage to prevent lysosomes from fusing with phagosomes and creating mature phagolysosomes. (wikipedia.org)
  • Assessment of phagosomes infected with Mycobacterium tuberculosis as a vaccine candidate against tuberculosis. (bvsalud.org)
  • We show here that T. whipplei survives within HeLa cells by controlling the biogenesis of its phagosome. (asm.org)
  • We previously obtained evidence that PKC-α plays a role in phagolysosome biogenesis ( 24 ), and, while investigating the mechanisms by which PKC-α modulates phagocytosis, we identified Syt V ( 25 ) as a molecule potentially interacting with PKC-α in phagosomes preparations (A.F.V. and A.D., unpublished observations). (jimmunol.org)
  • Modulation of phagosome biogenesis and escape into the cytosol is mediated by the Francisella pathogenicity island-encoded type VI-like secretion system. (frontiersin.org)
  • Biogenesis of the Francisella-containing phagosome (FCP) is arrested for ~15 min at the endosomal stage, followed by gradual bacterial escape into the cytosol, where the microbe proliferates. (helmholtz-hzi.de)
  • Collectively, these results reveal a novel function for Syt V in phagolysosome biogenesis and provide novel insight into the mechanism of vesicular proton-ATPase recruitment to maturing phagosomes. (inrs.ca)
  • Phagosomes have membrane-bound proteins to recruit and fuse with lysosomes to form mature phagolysosomes. (wikipedia.org)
  • Endosomes and lysosomes then fuse with the phagosome to contribute to the membrane, especially when the engulfed particle is very big, such as a parasite. (wikipedia.org)
  • Phagosomes fuse with lysosomes in their maturation process. (factbites.com)
  • Acid phosphatase cytochemistry revealed that phagosomes containing live L. pneumophila did not fuse with either primary or secondary lysosomes. (rupress.org)
  • Finally, phagosomes fuse with lysosomes and acquire hydrolases, such as cathepsin D ( 7 ), thus leading to the lysis of the microorganism. (asm.org)
  • Early stages of phagocytosis proceed normally in mauve mutant hemocytes but, unlike in wild type, late phagosomes fuse and generate large vacuoles containing many bacteria. (elsevier.com)
  • Electron microscopy studies were performed to evaluate the capacity of phagosomes to fuse with lysosomes labeled with bovine serum albumin-colloidal gold particles. (unifesp.br)
  • Phagosomes are large enough to degrade whole bacteria, or apoptotic and senescent cells, which are usually >0.5μm in diameter. (wikipedia.org)
  • The fusion of phagosomes and lysosomes releases toxic products that kill most bacteria and degrade them into fragments. (genome.jp)
  • In contrast to phagosomes containing live bacteria, the majority of phagosomes containing formalin-killed L. pneumophila were fused with lysosomes by acid phosphatase cytochemistry. (rupress.org)
  • Thus, we conclude that Salmonella-containing phagosomes acidify soon after formation and hypothesize that an acidic environment is necessary for survival and replication of the bacteria within the macrophage. (asm.org)
  • Collectively, our results contribute to the understanding of several aspects of the interaction between F.t. and its macrophage host cell, especially the uptake of bacteria, the phagosome maturation arrest and the phagosomal escape. (uio.no)
  • We developed two different protocols to isolate phagosomes containing dead or live bacteria modified with small magnetic particles, in conjunction with a synchronized phagocytosis protocol and nitrogen cavitation. (biomedcentral.com)
  • For dead bacteria, we performed analysis of the phagosome samples by microscopy and immunoblot, and demonstrated the appearance of maturation markers on isolated phagosomes. (biomedcentral.com)
  • The versatility and simplicity of the approach allow better control of phagosome isolation, the parameters of which are critical in studies of host-bacteria interaction and phagosome maturation. (biomedcentral.com)
  • In this paper we present a method where the attachment of magnetic particles to the prey allows rapid and gentle isolation of bacteria-containing phagosomes. (biomedcentral.com)
  • Electron micrographs showed that axenically cultivated trophozoites of the two Entamoeba species revealed morphological differences in the number of bacteria contained in a single phagosome and the size of phagosomes. (elsevier.com)
  • Apoptotic cells generated by programmed cell death are engulfed by phagocytes and enclosed within membrane-bound phagosomes. (rupress.org)
  • Early phagosomes are characterised by Rab5, which transition into Rab7 as the vesicle matures into late phagosomes. (wikipedia.org)
  • The vacuoles containing T. whipplei were acidic (pH 4.7 ± 0.3) and acquired vacuolar ATPase, responsible for the acidic pH of late phagosomes. (asm.org)
  • We compared the morphology of phagosomes and the kinetics of phagosome maturation using conventional light and electron microscopy and live imaging with video microscopy between the virulent E. histolytica and the closely-related, but non-virulent E. dispar species. (elsevier.com)
  • Other proteins such as Toll-like receptors are involved in pathogen pattern recognition and are often recruited to phagosomes but do not specifically trigger phagocytosis in non-phagocytic cells, so they are not considered phagocytic receptors. (wikipedia.org)
  • Histoplasma is a primary human fungal pathogen that survives and proliferates within host immune cells, particularly within the macrophage phagosome compartment. (asm.org)
  • Similarly, the maturation of phagosomes containing the fungal pathogen \(C\). \(neoformans\) was explored. (bham.ac.uk)
  • This provides a unique opportunity to interrogate native-like organelles using biophysical and biochemical assays, and understand the role of motor proteins in phagosome maturation and pathogen clearance. (bio-protocol.org)
  • This results in rapid directed transport of the phagosome toward microtubule minus ends, likely promoting phagolysosome fusion and pathogen degradation. (ccamp.res.in)
  • Phagocytosis and phagosome acidification are required for pathogen processing and MyD88-dependent responses to Staphylococcus aureus. (wizdom.ai)
  • Both microbial and apoptotic cells are delivered on a common route from phagosomes to lysosomes for degradation. (factbites.com)
  • We also tested our model as a tool for genetic analysis using 14-3-3ε mutants, and demonstrated altered phagosome maturation with delayed E. coli internalization, trafficking and/or degradation. (mdpi.com)
  • Phagosome degradation in the tapetal retinal pigment epithelium of the opossum. (arvojournals.org)
  • Ultrastructural and cytochemical features of phagosome degradation were examined in the tapetal retinal pigment epithelium (RPE) of the opossum. (arvojournals.org)
  • Both ultrastructural and cytochemical observations showed that degradation of phagosomes by lysosomes occurs only in this basal region. (arvojournals.org)
  • The acidity of phagosomes significantly differed between two species (4.58 ± 0.36 or 5.83 ± 0.38 in E. histolytica or E. dispar, respectively), which correlated well with the differences in the kinetics of degradation of promastigotes of GFP-expressirig Leishmania amazonensis. (elsevier.com)
  • A specific inhibitor of vacuolar ATPase, concanamycin A, interrupted both the acidification and degradation in phagosomes in both species, suggesting the ubiquitous role of vacuolar ATPase in the acidification and degradation in Entamoeba. (elsevier.com)
  • In contrast, inhibitors against microtubules or cysteine proteases (CP) showed distinct effects on degradation in phagosomes between these two species. (elsevier.com)
  • Although depolymerization of microtubules severely inhibited degradation in phagosomes of E. histolytica, it did not affect degradation in E. dispar. (elsevier.com)
  • Similarly, the inhibition of CP significantly reduced degradation in phagosomes of E. histolytica, but not in E. dispar. (elsevier.com)
  • These data suggest the presence of biochemical or functional differences in the involvement of microtubules and proteases in phagosome maturation and degradation between the two species. (elsevier.com)
  • They also deliver various membrane proteins to the phagosome and modify the organelle structure. (wikipedia.org)
  • To find proteins that are injected into host cells by the Dot/Icm transporter, we focused on bacterial gene products that may play a direct role in localization of ARF1 to phagosomes containing L. pneumophila . (sciencemag.org)
  • Phagosomes were re-isolated from cells at intervals after illumination and organelle-associated protein was retrieved and analyzed by Western blotting for proteins known to support motility. (arvojournals.org)
  • First of all, a comparison of phagosome proteomes of BMDMs and RAW 264.7 cells was performed, suggesting that there are significant differences for a large number of proteins including important receptors such as mannose receptor 1 and Siglec-1. (dundee.ac.uk)
  • Firstly, proteomics reveals a reduction of ER and lipid metabolic proteins to phagosomes by the inhibition of JNK, suggesting that TAK1/MKK7/JNK signalling might regulate phagosomal lipid handling. (dundee.ac.uk)
  • Moreover, TAK1/MKK7/JNK signalling was found for the first time to be specially recruited to phagosomes by K63 polyubiquitylation, and 55 novel K63 polyubiquitylation sites on 33 phagosomal proteins were identified, including MSR1. (dundee.ac.uk)
  • We have further ordered these candidates, which include the GTPases RAB-5 and RAB-7 and the HOPS complex, into a coherent linear pathway for the maturation of apoptotic cells within phagosomes. (nih.gov)
  • We ordered these candidates in our pathway, with DYN-1 functioning upstream of VPS-34 in the recruitment and/or retention of RAB-5 to the phagosome. (nih.gov)
  • Here, we identified UBC-13, an E2 ubiquitin-conjugating enzyme that functions in the same pathway with VPS-34 but in parallel to PIKI-1 to regulate PtdIns3P generation on phagosomes. (rupress.org)
  • These results suggest that LPC can effectively control Mtb growth by promoting phagosome maturation via cAMP-induced activation of the PKA-PI3K-p38 MAPK pathway. (frontiersin.org)
  • Finally, three hypotheses of the function of JNK pathway on phagosomes were described. (dundee.ac.uk)
  • Insertion of LPG into ganglioside GM1-containing microdomains excluded Syt V from phagosome membranes, enabling L. donovani promatigotes to inhibit the recruitment of the vesicular proton-ATPase to phagosomes, preventing their acidification. (inrs.ca)
  • Phagosomes can also form in non-professional phagocytes, but they can only engulf a smaller range of particles, and do not contain ROS. (wikipedia.org)
  • Professional phagocytes function at the hinge of innate and acquired immune responses by internalizing particulate material that is digested and sampled within the phagosome of the cell. (factbites.com)
  • Acidification of phagosomes has been proposed to have a key role in the microbicidal function of phagocytes. (nih.gov)
  • 2006) Internalization and phagosome escape required for Francisella to induce human monocyte IL-1beta processing and release. (wordnik.com)
  • In cooperation with the humoral adaptive immune system, coating of substrates with immunoglobulin G (IgG) antibodies enhances several aspects of phagocytosis, including the recognition of substrates by cell surface IgG (Fcγ) receptors, particle internalization, generation of microbicidal oxygen species, and targeting of lysosomes to phagosomes. (sciencemag.org)
  • Phagocytosis can be divided into four main steps: (i) recognition of the target particle, (ii) signaling to activate the internalization machinery, (iii) phagosome formation, and (iv) phagolysosome maturation. (hindawi.com)
  • Nascent phagosomes need to undergo a series of fusion and fission reactions to acquire the microbicidal properties required for the innate immune response. (neuroart2006.com)
  • Isolation of phagosome from macrophage ( cell line J774) infected with M. tuberculosis (H37) and M. bovis ( BCG ) at early and late phase of infection was done ensuing the identification and characterization of these phagosome . (bvsalud.org)
  • M. tuberculosis-containing phagosomes are delayed in the recruitment of the early endosome autoantigen EEA1. (elsevier.com)
  • Biochemical analysis of the phosphatidylinositol phosphates on M. tuberculosis-containing phagosomes revealed that PI-3-P acquisition was markedly retarded and reduced in comparison to IgG bead-containing phagosomes. (elsevier.com)
  • Through a combination of targeted and unbiased reverse genetic screens in Caenorhabditis elegans, and studies in mammalian cells, we have identified genes required for maturation of apoptotic-cell-containing phagosomes. (nih.gov)
  • Maturation of apoptotic cell-containing phagosomes leads to formation of phagolysosomes where cell corpses are degraded. (rupress.org)
  • Phagosome maturation depends on interactions (fusion events) with early and late endosomes as well as with lysosomes. (nih.gov)
  • This maturation of phagosomes involves regulated interaction with the other membrane organelles, including recycling endosomes, late endosomes and lysosomes. (genome.jp)
  • BSA-5 nm gold particles, LAMP-1 and cathepsin C, which represent markers of late endosomes/lysosomes, were localized to the majority of F.t.n. containing vacuoles 1 h and 4 h after the infection, which indicates that F.t.n. has a limited ability to modify phagosome maturation. (uio.no)
  • MHC-I present on the recycling endosomes would be delivered to phagosomes during this process. (reactome.org)
  • Inhibition of Rab5 may be at least partly responsible for this effect since immunodepletion of this protein precluded the fusion of phagosomes with endosomes (2 3 The mode of action of E 2012 Rab5 and the possible role of various other Rabs especially Rab7 in phagosomal maturation stay obscure. (neuroart2006.com)
  • As the membrane of the phagosome is formed by the fusion of the plasma membrane, the basic composition of the phospholipid bilayer is the same. (wikipedia.org)
  • Phagocytosis consists in recognition and ingestion of particles larger than 0.5 μ m into a plasma membrane derived vesicle, known as phagosome. (hindawi.com)
  • Formation of a novel phagosome by the Legionnaires' disease bacterium (Legionella pneumophila) in human monocytes. (rupress.org)
  • The crucial step in pathogenesis of tularemia is short and transient presence of the bacterium within phagosome. (helmholtz-hzi.de)
  • Modulation of Rab5 and Rab7 Recruitment to Phagosomes by Phosphatidylinositol 3-Kinase -- Vieira et al. (factbites.com)
  • In depth analysis of two additional candidate genes, the phosphatidylinositol 3 kinase (PI(3)K) vps-34 (A001762) and dyn-1/dynamin, showed an accumulation of internalized, but undegraded, corpses within abnormal Rab5-negative phagosomes. (nih.gov)
  • The class III phosphatidylinositol 3-kinase (PI3-kinase) VPS-34 coordinates with PIKI-1, a class II PI3-kinase, to produce PtdIns3P on phagosomes, thus promoting phagosome closure and maturation. (rupress.org)
  • YFP-2xFYVE, recognizing phosphatidylinositol 3-phosphate (PI(3)P), showed two patterns of phagosome labeling. (rupress.org)
  • We have presented detailed protocols for phagosome isolation, which can be adapted for use with different cell types and prey. (biomedcentral.com)
  • Techniques for the isolation and analysis of phagosomes are important experimental tools in phagocytosis research. (biomedcentral.com)
  • Moreover, a Mon1-Ccz1 complex (but not either protein alone) could bind Rab7 and could also influence Rab7 activation, suggesting Mon1-Ccz1 as an important link in progression from the Rab5-positive stage to the Rab7-positive stage of phagosome maturation. (wordnik.com)
  • H. pylori strains that were negative for the cancer associated virulence factor CagA were detected in phagosomes that recruited large amounts of EEA1 relative to Rab5, compared to CagA positive strains. (biomedcentral.com)
  • Accordingly Rab5 and Rab7 have been detected around the membranes of early and intermediate phagosomes respectively (12 13 23 Moreover using an in vitro reconstitution system Funato and colleagues (15) found that inhibition of Rab function by addition of extra Rab-GDP dissociation inhibitor impaired phagosome maturation. (neuroart2006.com)
  • Phagosomes in the apical and mid-RPE always had two membranes surrounding the discs and were acid phosphatase negative. (arvojournals.org)
  • The two patterns of PI(3)P on otherwise identical phagosomes indicated that organelle maturation does not necessarily follow a single path and that some features of phagosome maturation are integrated over the entire organelle. (rupress.org)
  • Moreover, the C-terminal region of SNX3 recruits galectin-9, a lectin implicated in protein and membrane recycling, which we identify as a further regulator of phagosome compaction. (medworm.com)
  • 2014). Using this method, we have recently shown cholesterol as a key regulator of phagosome transport and maturation (Rai et al . (bio-protocol.org)
  • 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. (nii.ac.jp)
  • Authoritative and cutting-edge, Phagocytosis and Phagosomes: Methods and Protocols aims to be an important resource for both experts in the field and for those investigators delving into phagocytosis and phagosome maturation for the first time. (springer.com)
  • Phagocytosis and Phagosomes: Methods and Protocols (Methods in Molecular Biology) by Humana Press: Humana Press 9781493965793 Hardcover, 1st ed. 2017. (abebooks.com)
  • Mtb has various survival strategies, including blockade of phagosome maturation and inhibition of antigen presentation. (frontiersin.org)
  • Specifically, the proposal aims will: 1) define the role Dectin-1 signaling in recruiting Rab7b to the fungal phagosome, 2) delineate the contribution of the NLRP3 inflammasome to phagosomal maturation, 3) determine the role of Dectin-1 signaling to class II MHC antigen presentation and CD4+ T cell stimulation. (grantome.com)
  • The phagosome then undergoes a maturation process whereby it transforms into a phagolysosome. (nih.gov)
  • Dynein Clusters into Lipid Microdomains on Phagosomes to Drive Rapid Transport toward Lysosomes. (ccamp.res.in)
  • In cell biology, a phagosome is a vesicle formed around a particle engulfed by a phagocyte via phagocytosis. (wikipedia.org)
  • A phagosome is formed when the specific receptors on the phagocyte surface recognize ligands on the particle surface. (genome.jp)
  • We show that the sorting nexin SNX3 is transported with Rab5a vesicles and that its PX domain enables vesicle-phagosome contact by binding to PI(3)P in the phagosomal coat. (medworm.com)
  • Study of bacterial adherence, phagosome maturation and phagosomal escape. (uio.no)
  • The goal was an easy, rapid, gentle and generally applicable method for studying phagosome maturation in neutrophils. (biomedcentral.com)
  • In neutrophils, the presence of Syt II on phagosomes suggested a role for this Ca 2+ sensor during phagocytosis and secretion ( 18 ). (jimmunol.org)
  • t = 60 min correspond to intermediate phagosomes (20 min of pulse + 40 min of chase), t = 120 min correspond to phagolysosomes (20 min of pulse + 100 min of chase). (bio-protocol.org)
  • Here, we show that dynein motors physically cluster into microdomains on the membrane of a phagosome as it matures inside cells. (ccamp.res.in)
  • This means a phagosome is several orders of magnitude bigger than an endosome, which is measured in nanometres. (wikipedia.org)
  • Recycling endosome-localized R-SNARE protein like RAB11a, VAMP3, and VAMP8 dock with target phagosome membrane Q-SNARE protein SNAP23. (reactome.org)
  • LC3 recruitment to fungal phagosomes requires activation of the fungal pattern receptor dectin-1. (broadinstitute.org)
  • We further demonstrate that reactive oxygen species generation by NADPH oxidase is required for LC3 recruitment to the fungal phagosome. (broadinstitute.org)
  • The ability of C. albicans to delay phagosome maturation is dependent on cell wall composition and fungal morphology. (asm.org)
  • Yet comparatively little is known about what controls the maturation of phagosomes following ingestion of fungal cells. (asm.org)
  • This project seeks to explain the molecular mechanisms involved in fungal phagosome maturation in order to develop novel fungal vaccine and immunotherapy strategies. (grantome.com)
  • The RalF protein is required for the localization of ARF on phagosomes containing L. pneumophila . (sciencemag.org)
  • The host protein ADP ribosylation factor-1 (ARF1) is found on phagosomes containing wild-type L. pneumophila but is not localized to phagosomes containing L. pneumophila dot/icm mutants ( 14 ). (sciencemag.org)
  • Because ARF1 localization on phagosomes containing L. pneumophila requires the Dot/Icm transporter, an injected bacterial protein may be required for ARF1 recruitment. (sciencemag.org)
  • LC3 recruitment to the phagosome also requires Syk signaling but is independent of all activity by Toll-like receptors and does not require the presence of the adaptor protein Card9. (broadinstitute.org)
  • Here, we show that the secreted Mtb protein tyrosine phosphatase (PtpA) binds to subunit H of the macrophage vacuolar-H + -ATPase (V-ATPase) machinery, a multisubunit protein complex in the phagosome membrane that drives luminal acidification. (pnas.org)
  • Impaired motility of phagosomes in the RPE on photic stress may result from dissociation of motor protein complexes and the supporting cytoskeleton from the organelle surface. (arvojournals.org)
  • The results indicate that complex changes occur, including transient suppression of mito-chondrial metabolism and protein synthesis, but are also consistent with the hypothesisthat the symbiosome is a phagosome that has undergone early arrest, raising the possi-bility of common mechanisms in the symbiotic interactions of corals and symbiotic seaanemones with their endosymbionts. (edu.au)
  • Several signaling molecules, including members of the protein kinase C (PKC) family of protein serine/threonine kinases, are activated during phagocytosis and associate to the phagosome during the maturation process ( 19 , 20 , 21 , 22 , 23 ). (jimmunol.org)
  • The team identified ten distinct mutants, only one of which had previously been shown to play a part in phagosome maturation arrest. (wordnik.com)
  • eff-1 mutations result in phagocytosis arrest with unsealed phagosomes. (nature.com)
  • Given the role these lipids play in the regulation of phagosome maturation these findings have implications with respect to the mechanisms behind the arrest of phagosome maturation. (elsevier.com)
  • Of newly recognized significance to Toxoplasma survival is the microbicidal effect of phagosome acidification, which reportedly can occur independently of fusion with other acidic vesicles. (nih.gov)
  • These phagosomes, collected along with the cytosol, show robust motion on in vitro polymerized microtubules. (bio-protocol.org)
  • Whilst inside the phagosome, F. tularensis temporarily induce proinflammatory cytokines in PI3K/Akt-dependent manner, which is counteracted by the induction of SHIP that negatively regulates PI3K/Akt activation and promotes bacterial escape into the cytosol. (frontiersin.org)
  • Inhibition of fusion of the phagocytic lysosomes (granules) with the phagosome . (factbites.com)
  • Chapters present methods and protocols on quantifying uptake and phagosome maturation using biophysical and biochemical approaches, proteomics, microscopy, and flow cytometry. (springer.com)
  • For the main goal of my project, I have performed a thorough proteomics analysis of the phagosome proteomes of non-activated (RestingMΦ), alternative-activated (IL4 treated, AAMΦ), classical-activated (LPS and IFNγ treated, CAMΦ) and reprogrammed (IL4 activated then LPS and IFNγ treated, ReMΦ) BMDMs. (dundee.ac.uk)
  • Both proteomics and phagosome function assays showed that the phagosome maturation is enhanced in AAMΦ and reduced in CAMΦ and ReMΦ. (dundee.ac.uk)
  • In this short review, we highlight how the use of latex beads as inert baits for phagocytosis and subsequent analysis by proteomics has changed our understanding of the phagosome. (tees.ac.uk)
  • 2016). Furthermore, this assay has helped us to elucidate the mechanism of disruption of phagosome transport by lipophosphoglycan (LPG) from the parasite Leishmania donovani . (bio-protocol.org)
  • We show that lipophosphoglycan, the major molecule implicated in immune evasion of Leishmania donovani, inhibits phagosome motion by disrupting the clustering and therefore the cooperative force generation of dynein. (ccamp.res.in)
  • The Leishmania donovani lipophosphoglycan excludes the vesicular proton-ATPase from phagosomes by impairing the recruitment of Synaptotagmin V In: 9e symposium annuel de parasitologie moléculaire du Québec, 18-19 juin 2009, Université McGill. (inrs.ca)
  • We also provide novel finding into the mechanism of Leishmania pathogenesis, whereby targeting of Syt V is part of the strategy used by L. donovani promastigotes to prevent phagosome acidification. (inrs.ca)