1
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Zuliani JP, Yamanouye N, Gutiérrez JM, Teixeira C. PKC-α is involved in the signaling of phagocytosis induced by two snake venom secretory PLA 2S in macrophages. Toxicon 2024; 247:107824. [PMID: 38908525 DOI: 10.1016/j.toxicon.2024.107824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Revised: 06/18/2024] [Accepted: 06/19/2024] [Indexed: 06/24/2024]
Abstract
Phagocytosis, an essential process for host defense, requires the coordination of a variety of signaling reactions. MT-II, an enzymatically inactive Lys49 phospholipase A2 (PLA2) homolog, and MT-III, a catalytically-active Asp49 PLA2, are known to activate phagocytosis in macrophages. In this study, the signaling pathways mediating phagocytosis, focusing on protein kinases, were investigated. Macrophages from male Swiss mice peritoneum were obtained 96 h after intraperitoneal thioglycolate injection. Phagocytosis was evaluated using non-opsonized zymosan particles in the presence or absence of specific inhibitors, as well as PKC and PKC-α localization by confocal microscopy. Moreover, protein kinase C (PKC) activity was assessed by γP32 ATP in macrophages stimulated by both PLA2s. Data showed that both sPLA2s increased phagocytosis. Cytochalasin D, staurosporine/H7, wortmannin, and herbimycin, inhibitors of actin polymerization, PKC, phosphoinositide 3-kinase (PI3K), and protein tyrosine kinase (PTK), respectively, significantly reduced phagocytosis induced by both PLA2s. PKC activity was increased in macrophages stimulated by both PLA2s. Actin polymerization and talin were evidenced by immunofluorescence and talin was recruited 5 min after both PLA2s stimulation. PKC and PKC-α localization within the cell were increased after 60 min of MT-II and MT-III stimulation. These data suggest that the effect of both PLA2s depends on actin cytoskeleton rearrangements and the activation of PKC, PI3K, and PTK signaling events required for phagocytosis.
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Affiliation(s)
- Juliana Pavan Zuliani
- Laboratório de Farmacologia - Instituto Butantan, São Paulo, Brazil; Laboratório de Imunologia Celular Aplicada à Saúde, Fundação Oswaldo Cruz Rondônia/FIOCRUZ-RO, Porto Velho, RO, Brazil; Dep. Medicina, Universidade Federal de Rondônia, UNIR, Porto Velho, RO, Brazil.
| | - Norma Yamanouye
- Laboratório de Farmacologia - Instituto Butantan, São Paulo, Brazil.
| | - José María Gutiérrez
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Catarina Teixeira
- Laboratório de Farmacologia - Instituto Butantan, São Paulo, Brazil.
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2
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Kim AB, Xiao Q, Yan P, Pan Q, Pandey G, Grathwohl S, Gonzales E, Xu I, Cho Y, Haecker H, Epelman S, Diwan A, Lee JM, DeSelm CJ. Chimeric antigen receptor macrophages target and resorb amyloid plaques. JCI Insight 2024; 9:e175015. [PMID: 38516884 PMCID: PMC11063938 DOI: 10.1172/jci.insight.175015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 01/31/2024] [Indexed: 03/23/2024] Open
Abstract
Substantial evidence suggests a role for immunotherapy in treating Alzheimer's disease (AD). While the precise pathophysiology of AD is incompletely understood, clinical trials of antibodies targeting aggregated forms of β amyloid (Aβ) have shown that reducing amyloid plaques can mitigate cognitive decline in patients with early-stage AD. Here, we describe what we believe to be a novel approach to target and degrade amyloid plaques by genetically engineering macrophages to express an Aβ-targeting chimeric antigen receptor (CAR-Ms). When injected intrahippocampally, first-generation CAR-Ms have limited persistence and fail to significantly reduce plaque load, which led us to engineer next-generation CAR-Ms that secrete M-CSF and self-maintain without exogenous cytokines. Cytokine secreting "reinforced CAR-Ms" have greater survival in the brain niche and significantly reduce plaque load locally in vivo. These findings support CAR-Ms as a platform to rationally target, resorb, and degrade pathogenic material that accumulates with age, as exemplified by targeting Aβ in AD.
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Affiliation(s)
- Alexander B. Kim
- Department of Radiation Oncology
- Bursky Center for Human Immunology and Immunotherapy
| | - Qingli Xiao
- Department of Neurology, and
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Ping Yan
- Department of Neurology, and
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Qiuyun Pan
- Department of Radiation Oncology
- Bursky Center for Human Immunology and Immunotherapy
| | - Gaurav Pandey
- Department of Radiation Oncology
- Bursky Center for Human Immunology and Immunotherapy
| | - Susie Grathwohl
- Department of Neurology, and
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Ernesto Gonzales
- Department of Neurology, and
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Isabella Xu
- Department of Neurology, and
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Yoonho Cho
- Department of Neurology, and
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Hans Haecker
- Department of Pathology, University of Utah, Salt Lake City, Utah, USA
| | - Slava Epelman
- Department of Medicine, Division of Cardiology, Peter Munk Cardiac Centre, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Abhinav Diwan
- Department of Neurology, and
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri, USA
- Departments of Medicine, Cell Biology and Physiology, Obstetrics and Gynecology, Washington University School of Medicine, St. Louis, Missouri, USA
- Medicine Service, St. Louis VA Medical Center, St. Louis, Missouri, USA
| | - Jin-Moo Lee
- Department of Neurology, and
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Carl J. DeSelm
- Department of Radiation Oncology
- Bursky Center for Human Immunology and Immunotherapy
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3
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Tian L, Choi SC, Murakami Y, Allen J, Morse HC, Qi CF, Krzewski K, Coligan JE. p85α recruitment by the CD300f phosphatidylserine receptor mediates apoptotic cell clearance required for autoimmunity suppression. Nat Commun 2016; 5:3146. [PMID: 24477292 DOI: 10.1038/ncomms4146] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 12/18/2013] [Indexed: 02/07/2023] Open
Abstract
Apoptotic cell (AC) clearance is essential for immune homeostasis. Here we show that mouse CD300f (CLM-1) recognizes outer membrane-exposed phosphatidylserine, and regulates the phagocytosis of ACs. CD300f accumulates in phagocytic cups at AC contact sites. Phosphorylation within CD300f cytoplasmic tail tyrosine-based motifs initiates signals that positively or negatively regulate AC phagocytosis. Y276 phosphorylation is necessary for enhanced CD300f-mediated phagocytosis through the recruitment of the p85α regulatory subunit of phosphatidylinositol-3-kinase (PI3K). CD300f-PI3K association leads to activation of downstream Rac/Cdc42 GTPase and mediates changes of F-actin that drive AC engulfment. Importantly, primary macrophages from CD300f-deficient mice have impaired phagocytosis of ACs. The biological consequence of CD300f deficiency is predisposition to autoimmune disease development, as FcγRIIB-deficient mice develop a systemic lupus erythematosus-like disease at a markedly accelerated rate if CD300f is absent. In this report we identify the mechanism and role of CD300f in AC phagocytosis and maintenance of immune homeostasis.
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Affiliation(s)
- Linjie Tian
- 1] Receptor Cell Biology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA [2]
| | - Seung-Chul Choi
- 1] Receptor Cell Biology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA [2]
| | - Yousuke Murakami
- Receptor Cell Biology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA
| | - Joselyn Allen
- Receptor Cell Biology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA
| | - Herbert C Morse
- Virology and Cellular Immunology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA
| | - Chen-Feng Qi
- Pathology core, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA
| | - Konrad Krzewski
- Receptor Cell Biology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA
| | - John E Coligan
- Receptor Cell Biology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA
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4
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Sun HN, Kim SU, Lee MS, Kim SK, Kim JM, Yim M, Yu DY, Lee DS. Nicotinamide Adenine Dinucleotide Phosphate (NADPH) Oxidase-Dependent Activation of Phosphoinositide 3-Kinase and p38 Mitogen-Activated Protein Kinase Signal Pathways Is Required for Lipopolysaccharide-Induced Microglial Phagocytosis. Biol Pharm Bull 2008; 31:1711-5. [DOI: 10.1248/bpb.31.1711] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Hu-Nan Sun
- Disease Model Research Center, Biological Resource Center, KRIBB
- College of Veterinary Medicine, Chungnam National University
| | - Sun-Uk Kim
- Disease Model Research Center, Biological Resource Center, KRIBB
| | - Mi-Sook Lee
- Department of Bioimaging, Korea Basic Science Institute
| | - Sang-Keun Kim
- College of Veterinary Medicine, Chungnam National University
| | - Jin-Man Kim
- Department of Pathology, College of Medicine, Chungnam National University
| | - Mijung Yim
- College of Pharmacy, Sookmyung Women's University
| | - Dae-Yeul Yu
- Disease Model Research Center, Biological Resource Center, KRIBB
| | - Dong-Seok Lee
- College of Natural Sciences, Kyungpook National University
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5
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Duchemin AM, Ren Q, Neff NH, Hadjiconstantinou M. GM1-induced activation of phosphatidylinositol 3-kinase: involvement of Trk receptors. J Neurochem 2007; 104:1466-77. [DOI: 10.1111/j.1471-4159.2007.05088.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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6
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Kamen LA, Levinsohn J, Swanson JA. Differential association of phosphatidylinositol 3-kinase, SHIP-1, and PTEN with forming phagosomes. Mol Biol Cell 2007; 18:2463-72. [PMID: 17442886 PMCID: PMC1924803 DOI: 10.1091/mbc.e07-01-0061] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
In macrophages, enzymes that synthesize or hydrolyze phosphatidylinositol (3,4,5)-trisphosphate [PI(3,4,5)P(3)] regulate Fcgamma receptor-mediated phagocytosis. Inhibition of phosphatidylinositol 3-kinase (PI3K) or overexpression of the lipid phosphatases phosphatase and tensin homologue (PTEN) and Src homology 2 domain-containing inositol phosphatase (SHIP-1), which hydrolyze PI(3,4,5)P(3) to phosphatidylinositol 4,5-bisphosphate and phosphatidylinositol 3,4-bisphosphate [PI(3,4)P(2)], respectively, inhibit phagocytosis in macrophages. To examine how these enzymes regulate phagosome formation, the distributions of yellow fluorescent protein (YFP) chimeras of enzymes and pleckstrin homology (PH) domains specific for their substrates and products were analyzed quantitatively. PTEN-YFP did not localize to phagosomes, suggesting that PTEN regulates phagocytosis globally within the macrophage. SHIP1-YFP and p85-YFP were recruited to forming phagosomes. SHIP1-YFP sequestered to the leading edge and dissociated from phagocytic cups earlier than did p85-cyan fluorescent protein, indicating that SHIP-1 inhibitory activities are restricted to the early stages of phagocytosis. PH domain chimeras indicated that early during phagocytosis, PI(3,4,5)P(3) was slightly more abundant than PI(3,4)P(2) at the leading edge of the forming cup. These results support a model in which phagosomal PI3K generates PI(3,4,5)P(3) necessary for later stages of phagocytosis, PTEN determines whether those late stages can occur, and SHIP-1 regulates when and where they occur by transiently suppressing PI(3,4,5)P(3)-dependent activities necessary for completion of phagocytosis.
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Affiliation(s)
- Lynn A. Kamen
- *Department of Microbiology and Immunology and
- Program in Immunology, University of Michigan Medical School, Ann Arbor, MI 48109-0620
| | | | - Joel A. Swanson
- *Department of Microbiology and Immunology and
- Program in Immunology, University of Michigan Medical School, Ann Arbor, MI 48109-0620
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7
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Joshi T, Butchar JP, Tridandapani S. Fcgamma receptor signaling in phagocytes. Int J Hematol 2006; 84:210-216. [PMID: 17050193 DOI: 10.1532/ijh97.06140] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2006] [Accepted: 07/05/2006] [Indexed: 01/16/2023]
Abstract
Fcgamma receptors are among the best-studied phagocytic receptors. The key features of Fcgamma receptor-mediated phagocytosis include phagocytic cup formation by extensive actin cytoskeletal rearrangements, particle engulfment, and the release of proinflammatory mediators such as cytokines and reactive oxygen species. These events are elegantly regulated by the simultaneous engagement of activating and inhibitory Fcgamma receptors and by intracellular signaling molecules. Extensive studies in the past several years have defined the molecular mechanisms of the phagocytic process. The purpose of this review is to revisit some of the well-established signaling pathways as well as to summarize the new findings in this field.
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Affiliation(s)
- Trupti Joshi
- Department of Internal Medicine, Dorothy M. Davis Heart and Lung Research Institute and Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio, USA
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8
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Sampaio SC, Santos MF, Costa EP, Rangel-Santos AC, Carneiro SM, Curi R, Cury Y. Crotoxin induces actin reorganization and inhibits tyrosine phosphorylation and activity of small GTPases in rat macrophages. Toxicon 2006; 47:909-19. [PMID: 16737726 DOI: 10.1016/j.toxicon.2006.03.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Revised: 03/06/2006] [Accepted: 03/08/2006] [Indexed: 01/12/2023]
Abstract
Crotoxin is the main neurotoxic component of Crotalus durissus terrificus snake venom. Previous work of our group demonstrated that this toxin or its phospholipase A(2) subunit inhibits macrophage spreading and phagocytosis. The phagocytic activity of macrophages is controlled by the rearrangement of actin cytoskeleton and activity of the small Rho GTPases. The effect of crotoxin and its subunit on actin reorganization and tyrosine phosphorylation in rat peritoneal macrophages, during phagocytosis of opsonized zymosan, was presently investigated. The crude venom was used as positive control. In addition, the effect of crotoxin on the activity of Rho and Rac1 small GTPases was examined. Transmission electron studies showed that the venom or crotoxin decreased the extent of spread cells and increased microprojections often extended from macrophage surface. Immunocytochemical assays demosntrated that the venom or toxins increased F-actin content in the cytoplasm of these cells, but induced a marked decrease of phosphotyrosine. These effects were abolished by treatment with zileuton, a 5-lipoxygenase inhibitor. Furthermore, crotoxin decreased membrane-associated RhoA and Rac1 in translocation assays. The present results indicate that the crotalid venom and crotoxin are able to induce cytoskeleton rearrangement in macrophages. This effect is associated with inhibition of tyrosine phosphorylation and of the activity of proteins involved in intracellular signalling pathways important for the complete phagocytic activity of these cells.
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Affiliation(s)
- S C Sampaio
- Laboratory of Pathophysiology, Butantan Institute, Av. Vital Brazil, 1500, 05503-900 São Paulo, Brazil
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9
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Kamimoto M, Rung-Ruangkijkrai T, Iwanaga T. Uptake ability of hepatic sinusoidal endothelial cells and enhancement by lipopolysaccharide. Biomed Res 2006; 26:99-107. [PMID: 16011302 DOI: 10.2220/biomedres.26.99] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The liver is one of the major organs that remove exogenous substances and waste products from the blood circulation. Hepatic macrophages (Kupffer cells) and sinusoidal endothelial cells are responsible for the scavenger function of the liver. The sinusoidal endothelial cells, called scavenger endothelial cells, are believed to take up only soluble substances and nanometer-sized particles under normal conditions, while Kupffer cells can ingest larger particles and whole cells. However, the sinusoidal endothelial cells may have the potential to take up considerably large particles under special conditions. In this morphological study, we compared the uptake ability between sinusoidal endothelial cells and Kupffer cells after intravenous injections of latex beads (20 nm, 100 nm and 500 nm in diameter), bovine serum albumin (BSA) and dextran. Under normal conditions, the sinusoidal endothelial cells vigorously took up 100-nm-sized latex beads as well as 20-nm latex beads. BSA and dextran were ingested by the endothelial cells but not the Kupffer cells. The administration of lipopolysaccharide (LPS), which mimics inflammation, stimulated the uptake by endothelial cells. The uptake of latex beads by Kupffer cells was also elevated under LPS-stimulated conditions, but the uptake of BSA and dextran by them was not. These findings suggest that the sinusoidal endothelial cells can ingest not only soluble substances but also larger particles than those expected, and their uptake ability is strengthened under inflammatory conditions.
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Affiliation(s)
- Miyuki Kamimoto
- Laboratory of Histology and Cytology, Graduate School of Medicine, Sapporo 060-8638, Japan
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10
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Ganesan LP, Wei G, Pengal RA, Moldovan L, Moldovan N, Ostrowski MC, Tridandapani S. The Serine/Threonine Kinase Akt Promotes Fcγ Receptor-mediated Phagocytosis in Murine Macrophages through the Activation of p70S6 Kinase. J Biol Chem 2004; 279:54416-25. [PMID: 15485887 DOI: 10.1074/jbc.m408188200] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Fc gamma receptor (Fc gamma R) clustering by immune complexes activates multiple signaling pathways leading to phagocytosis. We and others have previously reported that Akt is phosphorylated in response to Fc gamma R clustering. However, the functional consequence of Akt activation by Fc gamma R is not known. Using Raw 264.7 macrophage cells transfected to overexpress either constitutively active myristoylated (Myr)-Akt or a dominant-negative CAAX-Akt and bone marrow macrophages (BMMs) from wild-type and transgenic mice expressing macrophage-specific Myr-Akt, we analyzed the function of Akt in phagocytosis. We report that overexpression of Myr-Akt resulted in significant increase in phagocytic efficiency, whereas CAAX-Akt down-regulated phagocytosis in Raw 264.7 cells. Likewise BMMs expressing Myr-Akt displayed enhanced phagocytic ability. Analyzing the downstream effectors of Akt, we demonstrate that p70S6 kinase is constitutively phosphorylated in Myr-Akt-expressing BMMs. p70S6 kinase is reported to influence actin cytoskeleton and cell migration, suggesting that Akt may influence phagocytosis through the activation of p70S6 kinase. Consistent with this, overexpression of either wild-type or constitutively active but not a kinase-inactive p70S6 kinase in Raw 264.7 cells significantly enhanced phagocytosis. Likewise suppression of p70S6 kinase with rapamycin down-regulated phagocytic efficiency conferred by the expression of constitutively active Akt. These findings demonstrate a novel role for Akt in phagocytosis through the activation of p70S6 kinase.
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Affiliation(s)
- Latha P Ganesan
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, The Ohio State University, Columbus, Ohio 43210, USA
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11
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Cao X, Wei G, Fang H, Guo J, Weinstein M, Marsh CB, Ostrowski MC, Tridandapani S. The inositol 3-phosphatase PTEN negatively regulates Fc gamma receptor signaling, but supports Toll-like receptor 4 signaling in murine peritoneal macrophages. THE JOURNAL OF IMMUNOLOGY 2004; 172:4851-7. [PMID: 15067063 DOI: 10.4049/jimmunol.172.8.4851] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Fc gamma R clustering in macrophages activates signaling events that result in phagocytosis. Phagocytosis is accompanied by the generation harmful byproducts such as reactive oxygen radicals and production of inflammatory cytokines, which mandate that the phagocytic process be subject to a tight regulation. The molecular mechanisms involved in this regulation are not fully understood. In this study, we have examined the role of the inositol 3-phosphatase and tensin homologue deleted on chromosome 10 (PTEN) in Fc gamma R-induced macrophage function. We demonstrate that in ex vivo murine peritoneal macrophages that are deficient in PTEN expression, Fc gamma R-induced Akt and extracellular signal-regulated kinase phosphorylation are enhanced. Notably, PTEN(-/-) macrophages showed constitutively high phosphorylation of Akt. However, PTEN did not seem to influence tyrosine phosphorylation events induced by Fc gamma R clustering. Furthermore, PTEN(-/-) macrophages displayed enhanced phagocytic ability. Likewise, Fc gamma R-induced production of TNF-alpha, IL-6, and IL-10 was significantly elevated in PTEN(-/-) macrophages. Surprisingly, LPS-induced TNF-alpha production was down-regulated in PTEN(-/-) macrophages. Analyzing the molecular events leading to PTEN influence on LPS/Toll-like receptor 4 (TLR4) signaling, we found that LPS-induced activation of mitogen-activated protein kinases is suppressed in PTEN(-/-) cells. Previous reports indicated that LPS-induced mitogen-activated protein kinase activation is down-regulated by phosphatidylinositol 3-kinase through the activation of Akt. Our observation that Akt activation is basally enhanced in PTEN(-/-) cells suggests that PTEN supports TLR4-induced inflammatory responses by suppressing the activation of Akt. Thus, we conclude that PTEN is a negative regulator of Fc gamma R signaling, but a positive regulator of TLR4 signaling. These findings are the first to demonstrate a role for PTEN in Fc gamma R- and TLR4-mediated macrophage inflammatory response.
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Affiliation(s)
- Xianhua Cao
- Biophysics Program, Ohio State University, Columbus, OH 43210, USA
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12
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Song X, Tanaka S, Cox D, Lee SC. Fcγ receptor signaling in primary human microglia: differential roles of PI-3K and Ras/ERK MAPK pathways in phagocytosis and chemokine induction. J Leukoc Biol 2004; 75:1147-55. [PMID: 14982949 DOI: 10.1189/jlb.0403128] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Cryptococcus neoformans monoclonal antibody immune complex (IC) induces beta-chemokines and phagocytosis in primary human microglia via activation of Fc receptor for immunoglobulin G (FcgammaR). In this report, we investigated microglial FcgammaR signal-transduction pathways by using adenoviral-mediated gene transfer and specific inhibitors of cell-signaling pathways. We found that Src inhibitor PP2 and Syk inhibitor piceatannol inhibited phagocytosis, macrophage-inflammatory protein-1alpha (MIP-1alpha) release, as well as phosphorylation of extracellular-regulated kinase (ERK) and Akt, consistent with Src/Syk involvement early in FcgammaR signaling. Constitutively active mitogen-activated protein kinase kinase (MEK) induced MIP-1alpha, and Ras dominant-negative (DN) inhibited IC-induced ERK phosphorylation and MIP-1alpha production. These results suggest that the Ras/MEK/ERK pathway is necessary and sufficient in IC-induced MIP-1alpha expression. Neither Ras DN nor the MEK inhibitor U0126 inhibited phagocytosis. In contrast, phosphatidylinositol-3 kinase (PI-3K) inhibitors Wortmannin and LY294002 inhibited phagocytosis without affecting ERK phosphorylation or MIP-1alpha production. Conversely, Ras DN or U0126 did not affect Akt phosphorylation. Together, these results demonstrate distinct roles played by the PI-3K and Ras/MEK/ERK pathways in phagocytosis and MIP-1alpha induction, respectively. Our results demonstrating activation of functionally distinct pathways following microglial FcgammaR engagement may have implications for human central nervous system diseases.
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Affiliation(s)
- Xianyuan Song
- Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
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13
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Botelho RJ, Scott CC, Grinstein S. Phosphoinositide involvement in phagocytosis and phagosome maturation. Curr Top Microbiol Immunol 2004; 282:1-30. [PMID: 14594212 DOI: 10.1007/978-3-642-18805-3_1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Cells of the innate immune system engulf invading microorganisms into plasma membrane-derived vacuoles called phagosomes. Newly formed phagosomes gradually acquire microbicidal properties by a maturation process which involves sequential and coordinated rounds of fusion with endomembranes and concomitant fission. Some pathogens interfere with this maturation sequence and thereby evade killing by the immune cells, managing to survive intracellularly as parasites. Phosphoinositides seem to be intimately involved in the processes of phagosome formation and maturation, and initial observations suggest that the ability of some microorganisms to survive intracellularly is associated with alterations in phosphoinositide metabolism. This chapter presents a brief overview of phosphoinositides in cells of the immune system, their metabolism in the context of phagocytosis and phagosome maturation and their possible derangements during infectious pathogenosis.
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Affiliation(s)
- R J Botelho
- Programme in Cell Biology, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
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14
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Ganesan LP, Fang H, Marsh CB, Tridandapani S. The protein-tyrosine phosphatase SHP-1 associates with the phosphorylated immunoreceptor tyrosine-based activation motif of Fc gamma RIIa to modulate signaling events in myeloid cells. J Biol Chem 2003; 278:35710-7. [PMID: 12832410 DOI: 10.1074/jbc.m305078200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Fc gamma RIIa is a low affinity IgG receptor uniquely expressed in human cells that promotes phagocytosis of immune complexes and induces inflammatory cytokine gene transcription. Recent studies have revealed that phagocytosis initiated by Fc gamma RIIa is tightly controlled by the inositol phosphatase SHIP-1, and the protein-tyrosine phosphatase SHP-1. Whereas the molecular nature of SHIP-1 involvement with Fc gamma RIIa has been well studied, it is not clear how SHP-1 is activated by Fc gamma RIIa to mediate its regulatory effect. Here we report that Fc gamma RIIa clustering induces SHP-1 phosphatase activity in THP-1 cells. Using synthetic phosphopeptides, and stable transfectants expressing immunoreceptor tyrosine-based activation motif (ITAM) tyrosine mutants of Fc gamma RIIa, we demonstrate that SHP-1 associates with the phosphorylated amino-terminal ITAM tyrosine of Fc gamma RIIa, whereas the tyrosine kinase Syk associates with the carboxyl-terminal ITAM tyrosine. Association of SHP-1 with Fc gamma RIIa ITAM appears to suppress total cellular tyrosine phosphorylation. Furthermore, Fc gamma RIIa clustering results in the association of SHP-1 with key signaling molecules such as Syk, p85 subunit of PtdIns 3-kinase, and p62dok, suggesting that these molecules may be substrates of SHP-1 in this system. Finally, overexpression of wild-type SHP-1 but not catalytically deficient SHP-1 led to a down-regulation of NF kappa B-dependent gene transcription in THP-1 cells activated by clustering Fc gamma RIIa.
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MESH Headings
- Antigens, CD/chemistry
- Antigens, CD/genetics
- Antigens, CD/isolation & purification
- Antigens, CD/physiology
- Cell Line
- Humans
- Intracellular Signaling Peptides and Proteins
- Kinetics
- Mutagenesis, Site-Directed
- Phosphorylation
- Protein Tyrosine Phosphatase, Non-Receptor Type 6
- Protein Tyrosine Phosphatases/chemistry
- Protein Tyrosine Phosphatases/genetics
- Protein Tyrosine Phosphatases/metabolism
- Receptors, IgG/chemistry
- Receptors, IgG/genetics
- Receptors, IgG/isolation & purification
- Receptors, IgG/physiology
- Recombinant Proteins/chemistry
- Recombinant Proteins/metabolism
- Signal Transduction/physiology
- Transfection
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Affiliation(s)
- Latha P Ganesan
- Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine, The Dorothy M. Davis Heart and Lung Institute, and Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio 43210, USA
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15
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McCaw SE, Schneider J, Liao EH, Zimmermann W, Gray-Owen SD. Immunoreceptor tyrosine-based activation motif phosphorylation during engulfment of Neisseria gonorrhoeae by the neutrophil-restricted CEACAM3 (CD66d) receptor. Mol Microbiol 2003; 49:623-37. [PMID: 12864848 DOI: 10.1046/j.1365-2958.2003.03591.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Gonorrhea is characterized by a purulent urethral or cervical discharge consisting primarily of neutrophils associated with Neisseria gonorrhoeae. These interactions are facilitated by gonococcal colony opacity-associated (Opa) protein binding to host cellular CEACAM receptors. Of these, CEACAM3 is restricted to neutrophils and contains an immunoreceptor tyrosine-based activation motif (ITAM) reminiscent of that found within certain phagocytic Fc receptors. CEACAM3 was tyrosine phosphorylated by a Src family kinase-dependent process upon infection by gonococci expressing CEACAM-specific Opa proteins. This phosphorylation was necessary for efficient bacterial uptake; however, a less efficient uptake process became evident when kinase inhibitors or mutagenesis of the ITAM were used to prevent phosphorylation. Ligated CEACAM3 was recruited to a cytoskeleton-containing fraction, intense foci of polymerized actin were evident where bacteria attached to HeLa-CEACAM3, and disruption of polymerized actin by cytochalasin D blocked all bacterial uptake by these cells. These data support a model whereby CEACAM3 can mediate the Opa-dependent uptake of N. gonorrhoeae via either an efficient, ITAM phosphorylation-dependent process that resembles phagocytosis or a less efficient, tyrosine phosphorylation-independent mechanism.
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Affiliation(s)
- Shannon E McCaw
- Department of Medical Genetics and Microbiology, University of Toronto, Toronto, Canada
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16
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Kwiatkowska K, Frey J, Sobota A. Phosphorylation of FcgammaRIIA is required for the receptor-induced actin rearrangement and capping: the role of membrane rafts. J Cell Sci 2003; 116:537-50. [PMID: 12508114 DOI: 10.1242/jcs.00254] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Activation of Fcgamma receptor II (FcgammaRII) induces rearrangement of the actin-based cytoskeleton that serves as a driving force for FcgammaRII-mediated phagocytosis and FcgammaRII capping. To get insight into the signaling events that lead to the actin reorganization we investigated the role of raft-associated Src family tyrosine kinases in capping of FcgammaRII in U937 cells. After crosslinking, FcgammaRII was found to be recruited to detergent-resistant membrane domains (DRMs), rafts, where it coexisted with Lyn kinase and underwent tyrosine phosphorylation. Lyn was displaced from DRMs under the influence of DL-alpha-hydroxymyristic acid and 2-bromopalmitic acid, agents blocking N-terminal myristoylation and palmitoylation of proteins, respectively, and after disruption of DRM integrity by depletion of plasma membrane cholesterol with beta-cyclodextrin. Under these conditions, phosphorylation of the crosslinked FcgammaRII was diminished and assembly of FcgammaRII caps was blocked. The similar reduction of FcgammaRII cap formation correlated with inhibition of receptor phosphorylation was achieved with the use of PP1 and herbimycin A, specific inhibitors of Src family tyrosine kinases. Phosphorylation of FcgammaRIIA expressed in BHK cells, lacking endogenous FcgammaRs, was abolished by substitution of tyrosine 298 by phenylalanine in the ITAM of the receptor. The mutant receptor did not undergo translocation towards cap-like structures and failed to promote the receptor-mediated spreading of the cells, as compared to BHK cells transfected with the wild-type FcgammaRIIA. On the basis of these data, we suggest that tyrosine phosphorylation of activated FcgammaRIIA by raft-residing tyrosine kinases of the Src family triggers signaling pathways that control the rearrangement of the actin cytoskeleton required for FcgammaRII-mediated motility.
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Affiliation(s)
- Katarzyna Kwiatkowska
- Department of Cell Biology, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093 Warsaw, Poland. Universität Bielefeld, Fakultät für Chemie, Biochemie II, 33615 Bielefeld, Germany
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17
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Belanger PH, Johnston DA, Fratti RA, Zhang M, Filler SG. Endocytosis of Candida albicans by vascular endothelial cells is associated with tyrosine phosphorylation of specific host cell proteins. Cell Microbiol 2002; 4:805-12. [PMID: 12464011 DOI: 10.1046/j.1462-5822.2002.00232.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Candida albicans escapes from the bloodstream by invading the endothelial cell lining of the vasculature. In vitro, C. albicans invades endothelial cells by inducing its own endocytosis. We examined whether this process is regulated by the tyrosine phosphorylation of endothelial cell proteins. We found that endocytosis of wild-type C. albicans was accompanied by the tyrosine phosphorylation of two endothelial cell proteins with molecular masses of 80 and 82 kDa. The phosphorylation of these proteins was closely associated with the endocytosis of C. albicans because these proteins were phosphorylated in response to the endocytosis of both live and killed organisms, but they were not phosphorylated in endothelial cells infected with a poorly endocytosed strain of C. albicans. The tyrosine kinase inhibitors genistein and tyrphostin 47 blocked the phosphorylation of the two endothelial cell proteins and significantly reduced endocytosis of C. albicans. Therefore, C. albicans probably induces its own endocytosis by stimulating the tyrosine phosphorylation of two endothelial cell proteins.
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Affiliation(s)
- Paul H Belanger
- St John's Cardiovascular Research Center, Division of Infectious Diseases, Department of Medicine, Harbor-UCLA Research and Education Institute, Torrance, California 90502, USA
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18
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Nakamura K, Malykhin A, Coggeshall KM. The Src homology 2 domain-containing inositol 5-phosphatase negatively regulates Fcgamma receptor-mediated phagocytosis through immunoreceptor tyrosine-based activation motif-bearing phagocytic receptors. Blood 2002; 100:3374-82. [PMID: 12384440 DOI: 10.1182/blood-2002-03-0787] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Molecular mechanisms by which the Src homology 2 domain-containing inositol 5-phosphatase (SHIP) negatively regulates phagocytosis in macrophages are unclear. We addressed the issue using bone marrow-derived macrophages from FcgammaR- or SHIP-deficient mice. Phagocytic activities of macrophages from FcgammaRII(b)(-/-) and SHIP(-/-) mice were enhanced to a similar extent, relative to those from wild type. However, calcium influx was only marginally affected in FcgammaRII(b)(-/-), but greatly enhanced in SHIP(-/-) macrophages. Furthermore, SHIP was phosphorylated on tyrosine residues upon FcgammaR aggregation even in macrophages from FcgammaRII(b)(-/-) mice or upon clustering of a chimeric receptor containing CD8 and the immunoreceptor tyrosine-based activation motif (ITAM)-bearing gamma-chain or human-restricted FcgammaRIIa. These findings indicate that, unlike B cells, SHIP is efficiently phosphorylated in the absence of an immunoreceptor tyrosine-based inhibition motif (ITIM)-bearing receptor. We further demonstrate that SHIP directly bound to phosphorylated peptides derived from FcgammaRIIa with a high affinity, comparable to that of FcgammaRII(b). Lastly, FcgammaRIIa-mediated phagocytosis was significantly enhanced in THP-1 cells overexpressing dominant-negative form of SHIP in the absence of FcgammaRII(b). These results indicate that SHIP negatively regulates FcgammaR-mediated phagocytosis through all ITAM-containing IgG receptors using a molecular mechanism distinct from that in B cells.
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MESH Headings
- Amino Acid Motifs
- Animals
- Antigens, CD/chemistry
- Antigens, CD/metabolism
- Bone Marrow Cells/cytology
- CD8 Antigens/genetics
- CD8 Antigens/physiology
- Calcium Signaling
- GPI-Linked Proteins
- Humans
- Macrophages/physiology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Phagocytosis/physiology
- Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases
- Phosphoric Monoester Hydrolases/chemistry
- Phosphoric Monoester Hydrolases/deficiency
- Phosphoric Monoester Hydrolases/genetics
- Phosphoric Monoester Hydrolases/physiology
- Phosphorylation
- Phosphotyrosine/physiology
- Protein Processing, Post-Translational
- Receptors, IgG/chemistry
- Receptors, IgG/deficiency
- Receptors, IgG/metabolism
- Recombinant Fusion Proteins/metabolism
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Affiliation(s)
- Koji Nakamura
- Program in Immunobiology and Cancer, The Oklahoma Medical Research Foundation, 825 NE 13th Street, Oklahoma City, OK 73104, USA
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19
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Edberg JC, Qin H, Gibson AW, Yee AMF, Redecha PB, Indik ZK, Schreiber AD, Kimberly RP. The CY domain of the Fcgamma RIa alpha-chain (CD64) alters gamma-chain tyrosine-based signaling and phagocytosis. J Biol Chem 2002; 277:41287-93. [PMID: 12200451 DOI: 10.1074/jbc.m207835200] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Although the cytoplasmic domain of the human FcgammaRIa alpha-chain lacks tyrosine-based phosphorylation motifs, it modulates receptor cycling and receptor-specific cytokine production. The cytoplasmic domain of FcgammaRIa is constitutively phosphorylated, and the inhibition of dephosphorylation with okadaic acid, an inhibitor of type 1 and type 2A protein serine/threonine phosphatase, inhibits both receptor-induced activation of the early tyrosine phosphorylation cascade and receptor-specific phagocytosis. To explore the basis for these effects of the cytoplasmic domain of FcgammaRIa, we developed a series of human FcgammaRIa molecular variants, expressed in the murine macrophage cell line P388D1, and demonstrate that serine phosphorylation of the cytoplasmic domain is an important regulatory mechanism. Truncation of the cytoplasmic domain and mutation of the cytoplasmic domain serine residues to alanine abolish the okadaic acid inhibition of phagocytic function. In contrast, the serine mutants did not recapitulate the selective effects of cytoplasmic domain truncation on cytokine production. These results demonstrate for the first time a direct functional role for serine phosphorylation in the alpha-chain of FcgammaRIa and suggest that the cytoplasmic domain of FcgammaRI regulates the different functional capacities of the FcgammaRIa-receptor complex.
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Affiliation(s)
- Jeffrey C Edberg
- Departments of Medicine and Microbiology, The University of Alabama at Birmingham, 1530 3rd Avenue S, THT433A, Birmingham, AL 35294, USA.
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20
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Abstract
Phosphoinositide 3-kinases (PI3Ks) are an evolutionarily conserved family of signal transducing enzymes. A great variety of stimuli activate PI3K, leading to the transient accumulation of its lipid products in cell membranes. These lipids serve as second messengers to regulate the location and activity of an array of downstream effector molecules. In cells of the mammalian immune system, PI3K is activated by receptors for antigen, cytokines, costimulatory molecules, immunoglobulins and chemoattractants. Signaling via PI3K regulates immune cell proliferation, survival, differentiation, chemotaxis, phagocytosis, degranulation, and respiratory burst. Here we review our current understanding of PI3K signaling in leukocytes.
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Affiliation(s)
- David A Fruman
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697, USA.
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21
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Pricop L, Salmon JE. Redox regulation of Fcgamma receptor-mediated phagocytosis: implications for host defense and tissue injury. Antioxid Redox Signal 2002; 4:85-95. [PMID: 11970846 DOI: 10.1089/152308602753625889] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Recent advances in our understanding of the mechanisms that regulate acute and chronic inflammatory responses have revealed a key role for reactive oxygen intermediates in modulating the activation of neutrophils. Opsonized microbes and immune complexes initiate the oxidative burst by the engagement of receptors for immunoglobulin G, termed Fcgamma receptors. The regulation of phagocytic cell function by oxidant-sensitive signaling pathways optimizes host defense capabilities, but it also amplifies tissue damage. This review will focus on the cross-talk between Fcgamma receptors and reactive oxygen intermediates at sites of inflammation and its role in microbial immunity.
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Affiliation(s)
- Luminita Pricop
- Hospital for Special Surgery and Weill Medical College of Cornell University, Department of Medicine, New York, NY 10021, USA
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22
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García‐García E, Sánchez‐Mejorada G, Rosales C. Phosphatidylinositol 3‐kinase and ERK are required for NF‐κB activation but not for phagocytosis. J Leukoc Biol 2001. [DOI: 10.1189/jlb.70.4.649] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Erick García‐García
- Immunology Department, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City
| | - Gabriela Sánchez‐Mejorada
- Immunology Department, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City
| | - Carlos Rosales
- Immunology Department, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City
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23
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Cooney DS, Phee H, Jacob A, Coggeshall KM. Signal transduction by human-restricted Fc gamma RIIa involves three distinct cytoplasmic kinase families leading to phagocytosis. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 167:844-54. [PMID: 11441091 DOI: 10.4049/jimmunol.167.2.844] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Recent experiments indicate an important role for Src family and Syk protein tyrosine kinases and phosphatidylinositol 3-kinase in the signal transduction process initiated by mouse receptors for IgG and leading to phagocytosis. Considerably less is known regarding signal transduction by the human-restricted IgG receptor, FcgammaRIIa. Furthermore, the relationship among the Src family, Syk, and phosphatidylinositol 3-kinase in phagocytosis is not understood. Here, we show that FcgammaRIIa is phosphorylated by an Src family member, which results in recruitment and concomitant activation of the distal enzymes Syk and phosphatidylinositol 3-kinase. Using a FcgammaRI-p85 receptor chimera cotransfected with kinase-inactive mutants of Syk or application of a pharmacological inhibitor of Syk, we show that Syk acts in parallel with phosphatidylinositol 3-kinase. Our results indicate that FcgammaRIIa-initiated monocyte or neutrophil phagocytosis proceeds from the clustered IgG receptor to Src to phosphatidylinositol 3-kinase and Syk.
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Affiliation(s)
- D S Cooney
- Immunobiology and Cancer Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
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24
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Marshall JG, Booth JW, Stambolic V, Mak T, Balla T, Schreiber AD, Meyer T, Grinstein S. Restricted accumulation of phosphatidylinositol 3-kinase products in a plasmalemmal subdomain during Fc gamma receptor-mediated phagocytosis. J Cell Biol 2001; 153:1369-80. [PMID: 11425868 PMCID: PMC2150726 DOI: 10.1083/jcb.153.7.1369] [Citation(s) in RCA: 226] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Phagocytosis is a highly localized and rapid event, requiring the generation of spatially and temporally restricted signals. Because phosphatidylinositol 3-kinase (PI3K) plays an important role in the innate immune response, we studied the generation and distribution of 3' phosphoinositides (3'PIs) in macrophages during the course of phagocytosis. The presence of 3'PI was monitored noninvasively in cells transfected with chimeras of green fluorescent protein and the pleckstrin homology domain of either Akt, Btk, or Gab1. Although virtually undetectable in unstimulated cells, 3'PI rapidly accumulated at sites of phagocytosis. This accumulation was sharply restricted to the phagosomal cup, with little 3'PI detectable in the immediately adjacent areas of the plasmalemma. Measurements of fluorescence recovery after photobleaching were made to estimate the mobility of lipids in the cytosolic monolayer of the phagosomal membrane. Stimulation of phagocytic receptors induced a marked reduction of lipid mobility that likely contributes to the restricted distribution of 3'PI at the cup. 3'PI accumulation during phagocytosis was transient, terminating shortly after sealing of the phagosomal vacuole. Two factors contribute to the rapid disappearance of 3'PI: the dissociation of the type I PI3K from the phagosomal membrane and the persistent accumulation of phosphoinositide phosphatases.
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Affiliation(s)
- John G. Marshall
- Division of Cell Biology, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
| | - James W. Booth
- Division of Cell Biology, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
| | | | - Tak Mak
- Amgen Institute, Toronto, Ontario M5G 2C1, Canada
| | - Tamas Balla
- Endocrinology and Reproduction Research Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
| | - Alan D. Schreiber
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104
| | - Tobias Meyer
- Department of Molecular Pharmacology, Stanford University, Stanford, California 94305
| | - Sergio Grinstein
- Division of Cell Biology, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
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25
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Salmon JE, Pricop L. Human receptors for immunoglobulin G: key elements in the pathogenesis of rheumatic disease. ARTHRITIS AND RHEUMATISM 2001; 44:739-50. [PMID: 11315912 DOI: 10.1002/1529-0131(200104)44:4<739::aid-anr129>3.0.co;2-o] [Citation(s) in RCA: 133] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The structural diversity of Fc gammaR provides a mechanism by which IgG can elicit a broad range of cell responses. Fc gammaR vary in their affinity for IgG, their preference for IgG subclasses, the cell types in which they are expressed, and the intracellular signals which they elicit--stimulatory or inhibitory. Expansion in our knowledge of structure-function relationships among Fc gammaR has identified them as heritable risk factors for disease susceptibility and valuable targets for therapeutic modulation of the immune system.
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Affiliation(s)
- J E Salmon
- Hospital for Special Surgery and Weill Medical College of Cornell University, New York, New York 10021, USA
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26
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Abstract
The process of engulfing a foreign particle - phagocytosis - is of fundamental importance for a wide diversity of organisms. From simple unicellular organisms that use phagocytosis to obtain their next meal, to complex metazoans in which phagocytic cells represent an essential branch of the immune system, evolution has armed cells with a fantastic repertoire of molecules that serve to bring about this complex event. Regardless of the organism or specific molecules concerned, however, all phagocytic processes are driven by a finely controlled rearrangement of the actin cytoskeleton. A variety of signals can converge to locally reorganise the actin cytoskeleton at a phagosome, and there are significant similarities and differences between different organisms and between different engulfment processes within the same organism. Recent advances have demonstrated the complexity of phagocytic signalling, such as the involvement of phosphoinostide lipids and multicomponent signalling complexes in transducing signals from phagocytic receptors to the cytoskeleton. Similarly, a wide diversity of ‘effector molecules’ are now implicated in actin-remodelling downstream of these receptors.
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Affiliation(s)
- R C May
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
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27
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Coppolino MG, Kong C, Mohtashami M, Schreiber AD, Brumell JH, Finlay BB, Grinstein S, Trimble WS. Requirement for N-ethylmaleimide-sensitive factor activity at different stages of bacterial invasion and phagocytosis. J Biol Chem 2001; 276:4772-80. [PMID: 11092884 DOI: 10.1074/jbc.m007792200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Bacterial invasion, like the process of phagocytosis, involves extensive and localized protrusion of the host cell plasma membrane. To examine the molecular mechanisms of the membrane remodeling that accompanies bacterial invasion, soluble NSF attachment protein receptor (SNARE)-mediated membrane traffic was studied in cultured cells during infection by Salmonella typhimurium. A green fluorescent protein-tagged chimera of VAMP3, a SNARE characteristic of recycling endosomes, was found to accumulate at sites of Salmonella invasion. To analyze the possible role of SNARE-mediated membrane traffic in bacterial infection, invasion was measured in cells expressing a dominant-negative form of N-ethylmaleimide-sensitive factor (NSF), an essential regulator of membrane fusion. Inhibition of NSF activity did not affect cellular invasion by S. typhimurium nor the associated membrane remodeling. By contrast, Fcgamma receptor-mediated phagocytosis was greatly reduced in the presence of the mutant NSF. Most important, dominant-negative NSF significantly impaired the fusion of Salmonella-containing vacuoles with endomembranes. These observations indicate that the membrane protrusions elicited by Salmonella invasion, unlike those involved in phagocytosis, occur via an NSF-independent mechanism, whereas maturation of Salmonella-containing vacuoles is NSF-dependent.
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Affiliation(s)
- M G Coppolino
- Cell Biology Programme, Research Institute, The Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
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28
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Castellano F, Montcourrier P, Chavrier P. Membrane recruitment of Rac1 triggers phagocytosis. J Cell Sci 2000; 113 ( Pt 17):2955-61. [PMID: 10934035 DOI: 10.1242/jcs.113.17.2955] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rac1 is a Ρ-family GTP-binding protein that controls lamellipodia formation and membrane ruffling in fibroblasts. Recently, Rac1 and Cdc42, another member of the Ρ-family, have been shown to regulate Fc receptor-mediated phagocytosis in macrophages by controlling different steps of membrane and actin dynamics leading to particle engulfment. Here, we investigated the function of Rac1 using a membrane recruitment system that mimics phagocytosis. Recruitment of an activated Rac1 protein to the cytoplasmic domain of an engineered membrane receptor by using rapamycin as a bridge induces ingestion of latex beads bound to the receptor. Rac1-mediated bead uptake depends on actin polymerisation since actin filaments accumulate at the bead/membrane binding sites and internalisation is inhibited by cytochalasin D. Internalisation is also abolished upon substitution of Phe37 to Leu in the Rac1 effector region. Our results indicate that by promoting actin polymerisation at particle attachment sites, Rac1 by acting through specific downstream effectors induces plasma membrane remodeling that allows particle internalisation in a membrane-enclosed phagosome.
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Affiliation(s)
- F Castellano
- Centre d'Immunologie INSERM-CNRS de Marseille-Luminy, France
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29
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Tridandapani S, Lyden TW, Smith JL, Carter JE, Coggeshall KM, Anderson CL. The adapter protein LAT enhances fcgamma receptor-mediated signal transduction in myeloid cells. J Biol Chem 2000; 275:20480-7. [PMID: 10781611 DOI: 10.1074/jbc.m909462199] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
FcgammaR clustering in monocytes initiates a cascade of signaling events that culminate in biological responses such as phagocytosis, production of inflammatory cytokines, and generation of reactive oxygen species. We have identified and determined the function of the adapter protein linker of activation of T cell (LAT) in FcgammaR-mediated signaling and function. Clustering of FcgammaRs on the human monocytic cell line, THP-1, induces phosphorylation of a major 36-kDa protein which immunoreacts with anti-LAT antisera. Our data indicate that although both the 36-kDa and 38-kDa isoforms of LAT are expressed in THP-1 and U937 human monocytic cells, FcgammaR clustering induces phosphorylation of the 36-kDa isoform only. Co-immunoprecipitation experiments revealed a constitutive association of p36 LAT with both FcgammaRI and FcgammaRIIa immunoprecipitates, and an activation-induced association of LAT with PLCgamma1, Grb2, and the p85 subunit of phosphatidylinositol 3-kinase. Transient transfection experiments in COS-7 cells indicated that overexpression of a wild type but not a dominant-negative LAT, that is incapable of binding to p85, enhances phagocytosis by FcgammaRI. Furthermore, bone marrow-derived macrophages from LAT-deficient mice displayed reduced phagocytic efficiency in comparison to the macrophages from wild-type mice. Thus, we conclude that p36 LAT serves to enhance FcgammaR-induced signal transduction in myeloid cells.
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Affiliation(s)
- S Tridandapani
- Department of Internal Medicine, The Ohio State University, Columbus, Ohio 43210, USA
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30
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Coxon PY, Rane MJ, Powell DW, Klein JB, McLeish KR. Differential mitogen-activated protein kinase stimulation by Fc gamma receptor IIa and Fc gamma receptor IIIb determines the activation phenotype of human neutrophils. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 164:6530-7. [PMID: 10843711 DOI: 10.4049/jimmunol.164.12.6530] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Fc gamma Rs mediate immune complex-induced tissue injury. The hypothesis that Fc gamma RIIa and Fc gamma RIIIb control neutrophil responses by activating mitogen-activated protein kinases was examined. Homotypic and heterotypic cross-linking of Fc gamma RIIa and/or Fc gamma RIIIb resulted in a rapid, transient increase in ERK and p38 activity, with maximal stimulation between 1 and 3 min. Fc gamma RIIa and Fc gamma RIIIb stimulated distinct patterns of ERK and p38 activity, and heterotypic cross-linking failed to stimulate synergistic activation of either ERK or p38 activity. Both Fc gamma RIIa and Fc gamma RIIIb required activation of a nonreceptor tyrosine kinase and phosphatidylinositol 3-kinase for stimulation of ERK and p38. Inhibition of ERK activation with PD98059 enhanced H2O2 production stimulated by homotypic and heterotypic Fc gamma R cross-linking. Inhibition of p38 with SB203580 attenuated H2O2 production stimulated by Fc gamma RIIIb or heterotypic cross-linking, but had no effect on Fc gamma RIIa-stimulated H2O2 production. On the other hand, PD98059 inhibited actin polymerization stimulated by Fc gamma R cross-linking, while SB203580 had no effect. Inhibition of actin polymerization with cytochalasin D enhanced p38 activity stimulated by either Fc gamma RIIa or Fc gamma RIIIb, but cytochalasin D only enhanced H2O2 production stimulated by Fc gamma RIIIb. Our data indicate that Fc gamma RIIa and Fc gamma RIIIb independently activate ERK and p38. The two receptors demonstrate different efficacies for ERK and p38 activation, and they do not act cooperatively. ERK and p38 provide stimulatory and inhibitory signals for neutrophil responses to immune complexes. In addition, these data indicate that actin reorganization may play a role in mediating p38-dependent activation of respiratory burst upon stimulation of Fc gamma RIIIb in neutrophils.
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Affiliation(s)
- P Y Coxon
- Department of Medicine and Biochemistry and Molecular Biology, University of Louisville Health Sciences Center, KY 40202, USA
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31
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Downey GP, Botelho RJ, Butler JR, Moltyaner Y, Chien P, Schreiber AD, Grinstein S. Phagosomal maturation, acidification, and inhibition of bacterial growth in nonphagocytic cells transfected with FcgammaRIIA receptors. J Biol Chem 1999; 274:28436-44. [PMID: 10497205 DOI: 10.1074/jbc.274.40.28436] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Phagocytosis and killing of microbial pathogens by professional phagocytes is an essential component of the innate immune response. Recently, heterologous transfection of individual receptors into nonmyeloid cells has been used successfully to elucidate the early steps that signal phagosome formation. It is unclear, however, whether the vacuoles formed by such transfected cells are bona fide phagosomes, capable of fusion with endomembranes, of luminal acidification, and of controlling the growth of microorganisms. The aim of the current study was to determine whether COS-1 and Chinese hamster ovary cells, rendered phagocytic by expression of human FcgammaRIIA receptors, express the cellular machinery required to support phagosomal maturation. Immunolocalization studies demonstrated that early endosomes, as well as late endosomes and/or lysosomes, fuse sequentially with phagosomes in the transfectants. Microfluorescence ratio imaging of particles labeled with pH-sensitive dyes revealed that maturation of the phagosome was accompanied by luminal acidification. The drop in pH, which attained levels comparable to those reported in professional phagocytes, was prevented by inhibitors of vacuolar-type H(+)-ATPases. Optimal phagosomal acidification required elevation of cytosolic [Ca(2+)], suggesting that it results from fusion of endomembranes bearing proton pumps. Moreover, the transfected cells effectively internalized live bacteria. Opsonization was essential for bacterial internalization, implying that it occurred by FcgammaRIIA-mediated phagocytosis, as opposed to invasion. Uptake into phagolysosomes was associated with inhibition of bacterial growth, due at least in part to the low intraphagosomal pH. These studies indicate that the biochemical events that follow receptor-mediated particle internalization in cells transfected with FcgammaRIIA receptors closely resemble the process of phagosomal maturation in neutrophils and macrophages. FcgammaRIIA-transfected cells can, therefore, be used as a model for the study of additional aspects of phagocyte biology.
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Affiliation(s)
- G P Downey
- Division of Respirology, Department of Medicine, University of Toronto M5S 1A8, Ontario, Canada
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Maresco DL, Osborne JM, Cooney D, Coggeshall KM, Anderson CL. The SH2-Containing 5′-Inositol Phosphatase (SHIP) Is Tyrosine Phosphorylated after Fcγ Receptor Clustering in Monocytes. THE JOURNAL OF IMMUNOLOGY 1999. [DOI: 10.4049/jimmunol.162.11.6458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
Current models of FcγR signal transduction in monocytes describe a molecular cascade that begins upon clustering of FcγR with the phosphorylation of critical tyrosine residues in the cytoplasmic domains of FcγRIIa or the γ-chain subunit of FcγRI and FcγRIIIa. The cascade engages several other tyrosine-phosphorylated molecules, either enzymes or adapters, to manifest ultimately an array of biological responses, including phagocytosis, cell killing, secretion of a variety of inflammatory mediators, and activation. Continuing to assess systematically the molecules participating in the cascade, we have found that the SH2-containing 5′-inositol phosphatase (SHIP) is phosphorylated on tyrosine early and transiently after FcγR clustering. This molecule in other systems, such as B cells and mast cells, mediates an inhibitory signal. We find that clustering of either FcγRIIa or FcγRI is effective in inducing SHIP phosphorylation, that SHIP binds in vitro to a phosphorylated immunoreceptor tyrosine-based activation motif, peptide from the cytoplasmic domain of FcγRIIa in activation-independent fashion, although SHIP binding increases upon cell activation, and that FcγRIIb and FcγRIIc are not responsible for the observed SHIP phosphorylation. These findings prompt us to propose that SHIP inhibits FcγR-mediated signal transduction by engaging immunoreceptor tyrosine-based activation motif-containing cytoplasmic domains of FcγRIIa and FcγRI-associated γ-chain.
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Affiliation(s)
| | | | - Damon Cooney
- †Microbiology, Ohio State University, Columbus, OH 43210
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