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LC3 associated phagocytosis

Andree Hubber, Tomoko Kubori, Cevayir Coban, Takeshi Matsuzawa, Michinaga Ogawa, Tsuyoshi Kawabata, Tamotsu Yoshimori, Hiroki Nagai
The evolutionarily conserved processes of endosome-lysosome maturation and macroautophagy are established mechanisms that limit survival of intracellular bacteria. Similarly, another emerging mechanism is LC3-associated phagocytosis (LAP). Here we report that an intracellular vacuolar pathogen, Legionella dumoffii, is specifically targeted by LAP over classical endocytic maturation and macroautophagy pathways. Upon infection, the majority of L. dumoffii resides in ER-like vacuoles and replicate within this niche, which involves inhibition of classical endosomal maturation...
March 20, 2017: Scientific Reports
L S Frost, A Dhingra, J Reyes-Reveles, K Boesze-Battaglia
There is increasing evidence documenting the critical role played by autophagic and autophagy-associated processes in maintaining cell homeostasis and overall systemic health. Autophagy is considered a degradative as well as a recycling pathway that relies on encapsulated intracellular components trafficking to and fusing with degradative compartments, including lysosomes. In this chapter, we describe the use of DQ™-BSA to study autophagosome-lysosome fusion as well as a means by which to analyze hybrid autophagic pathways...
2017: Methods in Enzymology
Rachel Ettinger, Jodi L Karnell, Jill Henault, Santosh K Panda, Jeffrey M Riggs, Roland Kolbeck, Miguel A Sanjuan
Autoantibodies of the IgG subclass are pathogenic in a number of autoimmune disorders such as systemic lupus erythomatosus. The presence of circulating IgE autoantibodies in autoimmune patients has also been known for almost 40 years. Despite their role in allergies, IgE autoantibodies are not associated with a higher rate of atopy in these patients. However, recently they have been recognized as active drivers of autoimmunity through mechanisms involving the secretion of Type I interferons by plasmacytoid dendritic cells (pDC), the recruitment of basophils to lymph nodes, and the activation of adaptive immune responses through B and T cells...
February 2017: Autoimmunity
Tonia Akoumianaki, Georgios Chamilos
Unabated inflammation and impaired antifungal immunity underlie genetic defects in NOX-2-dependent activation of LC3-associated phagocytosis (LAP). In this issue of Cell Host & Microbe, Oikonomou et al. (2016) identify a molecular link between IFN-γ/DAPK1 signaling, the proteosomal degradation pathway, and LAP that is critical for dampening Aspergillus-triggered immunopathology.
December 14, 2016: Cell Host & Microbe
Vasilis Oikonomou, Silvia Moretti, Giorgia Renga, Claudia Galosi, Monica Borghi, Marilena Pariano, Matteo Puccetti, Carlo A Palmerini, Lucia Amico, Alessandra Carotti, Lucia Prezioso, Angelica Spolzino, Andrea Finocchi, Paolo Rossi, Andrea Velardi, Franco Aversa, Valerio Napolioni, Luigina Romani
Defects in a form of noncanonical autophagy, known as LC3-associated phagocytosis (LAP), lead to increased inflammatory pathology during fungal infection. Although LAP contributes to fungal degradation, the molecular mechanisms underlying LAP-mediated modulation of inflammation are unknown. We describe a mechanism by which inflammation is regulated during LAP through the death-associated protein kinase 1 (DAPK1). The ATF6/C/EBP-β/DAPK1 axis activated by IFN-γ not only mediates LAP to Aspergillus fumigatus but also concomitantly inhibits Nod-like receptor protein 3 (NLRP3) activation and restrains pathogenic inflammation...
December 14, 2016: Cell Host & Microbe
Ursula Madjo, Olivier Leymarie, Stéphane Frémont, Aurelia Kuster, Mélanie Nehlich, Sarah Gallois-Montbrun, Katy Janvier, Clarisse Berlioz-Torrent
BST2 (bone marrow stromal antigen 2)/tetherin is a restriction factor of enveloped viruses, which blocks the release of viral particles. HIV-1 encodes proteins that antagonize this innate barrier, including the accessory protein Vpu. Here, we investigate whether the autophagy pathway and/or ATG proteins are hijacked by HIV-1 Vpu to circumvent BST2 restriction of viral release. We report that BST2 and Vpu are present in LC3-positive compartments. We found that Vpu selectively interacts with the ATG8 ortholog LC3C through the Vpu L63VEM66 sequence...
November 22, 2016: Cell Reports
Laure-Anne Ligeon, Susana Romao, Christian Münz
The noncanonical macroautophagy pathway, LC3-associated phagocytosis (LAP) has recently emerged as an important catabolic process involved during exogenous antigen processing. It has been described that in human macrophages and dendritic cells the direct recruitment of LC3 to the phagosomal membrane is associated with its maturation impairment, allowing the stabilization of the cargo to prolong antigen presentation on major histocompatibility complex (MHC) class II molecules.In this chapter, we describe methods to monitor, manipulate, and understand the role of LAP during MHC class II presentation...
2017: Methods in Molecular Biology
Gholamreza Fazeli, Michaela Trinkwalder, Linda Irmisch, Ann Marie Wehman
In animals, the midbody coordinates the end of cytokinesis when daughter cells separate through abscission. The midbody was thought to be sequestered by macroautophagy, but recent evidence suggests that midbodies are primarily released and phagocytosed. It was unknown, however, whether autophagy proteins play a role in midbody phagosome degradation. Using a protein degradation assay, we show that midbodies are released in Caenorhabditis elegans Released midbodies are known to be internalized by actin-driven phagocytosis, which we show requires the RAB-5 GTPase to localize the class III phosphoinositide 3-kinase (PI3K) complex at the cortex...
October 15, 2016: Journal of Cell Science
Marija Cemma, Sergio Grinstein, John H Brumell
Phagocytosis plays a central role in immunity and tissue homeostasis. After internalization of cargo into single-membrane phagosomes, these compartments undergo a maturation sequences that terminates in lysosome fusion and cargo degradation. Components of the autophagy pathway have recently been linked to phagosome maturation in a process called LC3-associated phagocytosis (LAP). In this process, autophagy machinery is thought to conjugate LC3 directly onto the phagosomal membrane to promote lysosome fusion...
September 2016: Autophagy
Urmi Bandyopadhyay, Michael Overholtzer
The autophagy-related process LC3-Associated Phagocytosis, or LAP, is known to control the degradation of engulfed cells and microorganisms. Now Martinez et al. discover that LAP controls immune responses to dying cells and its inhibition leads to development of Systemic Lupus Erythematosus-like disease.
August 2016: Cell Research
Christine Matte, Pierre-André Casgrain, Olivier Séguin, Neda Moradin, Wan Jin Hong, Albert Descoteaux
The protozoan Leishmania parasitizes macrophages and evades the microbicidal consequences of phagocytosis through the inhibition of phagolysosome biogenesis. In this study, we investigated the impact of this parasite on LC3-associated phagocytosis, a non-canonical autophagic process that enhances phagosome maturation and functions. We show that whereas internalization of L. major promastigotes by macrophages promoted LC3 lipidation, recruitment of LC3 to phagosomes was inhibited through the action of the parasite surface metalloprotease GP63...
June 2016: PLoS Pathogens
Rachasak Boonhok, Nattawan Rachaphaew, Apisak Duangmanee, Pornpimol Chobson, Sittiporn Pattaradilokrat, Pongsak Utaisincharoen, Jetsumon Sattabongkot, Marisa Ponpuak
IFN-γ is a major regulator of immune functions and has been shown to induce liver-stage Plasmodium elimination both in vitro and in vivo. The molecular mechanism responsible for the restriction of liver-stage Plasmodium downstream of IFN-γ remains uncertain, however. Autophagy, a newly described immune defense mechanism, was recently identified as a downstream pathway activated in response to IFN-γ in the control of intracellular infections. We thus hypothesized that the killing of liver-stage malarial parasites by IFN-γ involves autophagy induction...
June 21, 2016: Proceedings of the National Academy of Sciences of the United States of America
Evelien G G Sprenkeler, Mark S Gresnigt, Frank L van de Veerdonk
LC3-associated phagocytosis (LAP) is a non-canonical autophagy pathway involved in the maturation of single-membrane phagosomes and subsequent killing of ingested pathogens by phagocytes. This pathway is initiated following recognition of pathogens by pattern recognition receptors and leads to the recruitment of LC3 into the phagosomal membrane. This form of phagocytosis is utilized for the antifungal host defence and is required for an efficient fungal killing. Here, we provide an overview of the LAP pathway and review the role of LAP in anti-Aspergillus host defence, as well as mechanisms induced by Aspergillus that modulate LAP to promote its survival in the host...
September 2016: Cellular Microbiology
Jennifer Martinez, Larissa D Cunha, Sunmin Park, Mao Yang, Qun Lu, Robert Orchard, Quan-Zhen Li, Mei Yan, Laura Janke, Cliff Guy, Andreas Linkermann, Herbert W Virgin, Douglas R Green
Defects in clearance of dying cells have been proposed to underlie the pathogenesis of systemic lupus erythematosus (SLE). Mice lacking molecules associated with dying cell clearance develop SLE-like disease, and phagocytes from patients with SLE often display defective clearance and increased inflammatory cytokine production when exposed to dying cells in vitro. Previously, we and others described a form of noncanonical autophagy known as LC3-associated phagocytosis (LAP), in which phagosomes containing engulfed particles, including dying cells, recruit elements of the autophagy pathway to facilitate maturation of phagosomes and digestion of their contents...
May 5, 2016: Nature
Jenny M Tam, Michael K Mansour, Mridu Acharya, Anna Sokolovska, Allison K Timmons, Adam Lacy-Hulbert, Jatin M Vyas
Autophagy plays an important role in maintaining cell homeostasis by providing nutrients during periods of starvation and removing damaged organelles from the cytoplasm. A marker in the autophagic process is the reversible conjugation of LC3, a membrane scaffolding protein, to double membrane autophagosomes. Recently, a role for LC3 in the elimination of pathogenic bacteria and fungi, including Candida albicans (C. albicans), was demonstrated, but these organisms reside in single membrane phagosomes. This process is distinct from autophagy and is termed LC3-associated phagocytosis (LAP)...
2016: Pathogens
Georgios Chamilos, Tonia Akoumianaki, Irene Kyrmizi, Axel Brakhage, Anne Beauvais, Jean-Paul Latge
Intracellular swelling of conidia of the major human airborne fungal pathogen Aspergillus fumigatus results in surface exposure of immunostimulatory pathogen-associated molecular patterns (PAMPs) and triggers activation of a specialized autophagy pathway called LC3-associated phagocytosis (LAP) to promote fungal killing. We have recently discovered that, apart from PAMPs exposure, cell wall melanin removal during germination of A. fumigatus is a prerequisite for activation of LAP. Importantly, melanin promotes fungal pathogenicity via targeting LAP, as a melanin-deficient A...
May 3, 2016: Autophagy
D R Green, T H Oguin, J Martinez
Phagocytic cells of the immune system must constantly survey for, recognize, and efficiently clear the billions of cellular corpses that arise as a result of development, stress, infection, or normal homeostasis. This process, termed efferocytosis, is critical for the prevention of autoimmune and inflammatory disorders, and persistence of dead cells in tissue is characteristic of many human autoimmune diseases, notably systemic lupus erythematosus. The most notable characteristic of the efferocytosis of apoptotic cells is its 'immunologically silent' response...
June 2016: Cell Death and Differentiation
Masashi Kanayama, Keiko Danzaki, You-Wen He, Mari L Shinohara
Recruiting pathogenic T cells to the central nervous system (CNS) is a critical step during the development of experimental autoimmune encephalomyelitis (EAE). Here, we report that the absence of autophagy and microtubule-associated protein 1A/1B-light chain 3-associated phagocytosis significantly delayed the onset of EAE in Atg7 conditional knockout (Atg7 CKO) mice in myeloid cells. T-helper cell-cell priming appeared to be normal in the Atg7 CKO mice, but the mice showed significant accumulation of Th17 cells in the lung...
September 2016: International Immunology
Masashi Kanayama, Mari L Shinohara
Autophagy was initially characterized as a process to digest cellular components, including damaged cell organelles or unused proteins. However, later studies showed that autophagy plays an important role to protect hosts from microbial infections. Accumulating evidences showed the contribution of autophagy itself and autophagy-related proteins (ATGs) in the clearance of bacteria, virus, and parasites. A number of studies also revealed the molecular mechanisms by which autophagy is initiated and developed. Furthermore, it is now understood that some ATGs are shared between two distinct processes; autophagy and LC3-associated phagocytosis (LAP)...
2016: Frontiers in Immunology
Ming Shi, Yifan Zhang, Leyuan Liu, Tingting Zhang, Fang Han, Joseph Cleveland, Fen Wang, Wallace L McKeehan, Yu Li, Dekai Zhang
Phagocytosis is a critical cellular process for innate immune defense against microbial infection. The regulation of phagocytosis process is complex and has not been well defined. An intracellular molecule might regulate cell surface-initiated phagocytosis, but the underlying molecular mechanism is poorly understood (1). In this study, we found that microtubule-associated protein 1S (MAP1S), a protein identified recently that is involved in autophagy (2), is expressed primarily in macrophages. MAP1S-deficient macrophages are impaired in the phagocytosis of bacteria...
January 15, 2016: Journal of Biological Chemistry
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