101
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Crow AR, Song S, Freedman J, Helgason CD, Humphries RK, Siminovitch KA, Lazarus AH. IVIg-mediated amelioration of murine ITP via FcgammaRIIB is independent of SHIP1, SHP-1, and Btk activity. Blood 2003; 102:558-60. [PMID: 12649142 DOI: 10.1182/blood-2003-01-0023] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
It has been established that amelioration of murine immune thrombocytopenia purpura (ITP) by IVIg is dependent on the inhibitory receptor FcgammaRIIB. Co-cross-linking of the FcgammaRIIB with the B-cell receptor complex or with FcepsilonRI in mast cells results in cell inhibition, which is mediated by recruitment of the inositol phosphatase SHIP1 to the cytoplasmic tail of the FcgammaR. The FcgammaRIIB can also associate with protein tyrosine phosphatase SHP-1 as a potential secondary target of the receptor. Alternatively, homoaggregation of FcgammaRIIB can induce a proapoptotic state in B cells that is dependent on the presence of Bruton tyrosine kinase (Btk), a kinase also expressed in monocytes. We sought to determine if these signaling pathways may direct IVIg-mediated FcgammaRIIB-dependent regulation of in vivo monocyte function in a murine model of ITP in which IVIg functions in an FcgammaRIIB-dependent manner. We demonstrate that mice deficient in SHIP1, SHP-1, and Btk respond to the ameliorating effects of IVIg with the same kinetics as control mice. We conclude that IVIgmediated inhibitory pathways operating via monocyte FcgammaRIIB may involve a transmembrane signaling pathway different from that of B cells.
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MESH Headings
- Agammaglobulinaemia Tyrosine Kinase
- Animals
- Antigens, CD/physiology
- Autoimmune Diseases/enzymology
- Autoimmune Diseases/immunology
- Autoimmune Diseases/therapy
- B-Lymphocytes/enzymology
- B-Lymphocytes/immunology
- Immunoglobulins, Intravenous/therapeutic use
- Intracellular Signaling Peptides and Proteins
- Mast Cells/immunology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Models, Animal
- Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases
- Phosphoric Monoester Hydrolases/deficiency
- Phosphoric Monoester Hydrolases/genetics
- Phosphoric Monoester Hydrolases/physiology
- Phosphorylation
- Protein Processing, Post-Translational
- Protein Tyrosine Phosphatase, Non-Receptor Type 6
- Protein Tyrosine Phosphatases/deficiency
- Protein Tyrosine Phosphatases/genetics
- Protein Tyrosine Phosphatases/physiology
- Protein-Tyrosine Kinases/deficiency
- Protein-Tyrosine Kinases/genetics
- Protein-Tyrosine Kinases/physiology
- Purpura, Thrombocytopenic, Idiopathic/enzymology
- Purpura, Thrombocytopenic, Idiopathic/immunology
- Purpura, Thrombocytopenic, Idiopathic/therapy
- Receptors, IgG/physiology
- Signal Transduction/physiology
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Affiliation(s)
- Andrew R Crow
- Transfusion Medicine Research, St Michael's Hospital, Toronto, ON, Canada
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102
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Pengal RA, Ganesan LP, Fang H, Marsh CB, Anderson CL, Tridandapani S. SHIP-2 inositol phosphatase is inducibly expressed in human monocytes and serves to regulate Fcgamma receptor-mediated signaling. J Biol Chem 2003; 278:22657-63. [PMID: 12690104 DOI: 10.1074/jbc.m302907200] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
SHIP-2, a recently identified inositol 5'-phosphatase, shares high level homology with SHIP-1. Although the role of SHIP-1 has been extensively studied, the role of SHIP-2 in myeloid cell functions is not known. Here, we have analyzed the expression patterns, molecular mechanism of activation, and function of SHIP-2 in human myeloid cell Fcgamma receptor (FcgammaR) signaling. We report that SHIP-2 is expressed in transformed myeloid cells and in primary macrophages, but not in peripheral blood monocytes. Treatment of peripheral blood monocytes with bacterial lipopolysaccharide induced expression of SHIP-2 in a dose-dependent manner. FcgammaRIIa clustering in THP-1 cells induced SHIP-2 tyrosine phosphorylation, suggesting a role for SHIP-2 in modulating FcgammaR-mediated function. Consistent with this notion, overexpression of wild-type SHIP-2 (but not catalytically deficient SHIP-2) in THP-1 cells almost completely abrogated NFkappaB-mediated gene transcription in response to FcgammaRIIa clustering. Furthermore, FcgammaRIIa-induced Akt activation was blocked by wild-type SHIP-2, but not by a catalytically deficient mutant of SHIP-2. Additional experiments analyzing the molecular mechanism of SHIP-2 induction by FcgammaRIIa revealed that SHIP-2 associated with the phosphorylated FcgammaRIIa immunoreceptor tyrosine-based activation motif via the SHIP-2 SH2 domain. Thus, an SH2 domain mutant of SHIP-2 failed to associate with FcgammaRIIa or to become tyrosine-phosphorylated upon FcgammaRIIa clustering. Finally, we also demonstrate that SHIP-2 phosphorylation was induced by FcgammaRI clustering in THP-1 cells. These findings unravel a novel level of regulation of FcgammaR-mediated activation of human myeloid cells by the expression and function of the inositol phosphatase SHIP-2.
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Affiliation(s)
- Ruma A Pengal
- Molecular, Cellular, and Developmental Biology Program, Dorothy M. Davis Heart and Lung Institute, James Cancer Hospital, Ohio State University, Columbus 43210, USA
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103
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Huang ZY, Hunter S, Kim MK, Indik ZK, Schreiber AD. The effect of phosphatases SHP-1 and SHIP-1 on signaling by the ITIM- and ITAM-containing Fcgamma receptors FcgammaRIIB and FcgammaRIIA. J Leukoc Biol 2003; 73:823-9. [PMID: 12773515 DOI: 10.1189/jlb.0902454] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Inositol and tyrosine phosphatases have been implicated in inhibitory signaling by an Fc receptor for immunoglobulin G, FcgammaRIIB, in B cells, mast cells, and monocytes. Here, we propose a role for the Src homology 2 (SH2)-containing tyrosine phosphatase-1 (SHP-1) in FcgammaRIIB-mediated inhibition of FcgammaR signaling. Coexpression of SHP-1 enhances FcgammaRIIB-mediated inhibition of FcgammaRIIA phagocytosis in COS-1 cells. SHP-1 also enhances the reduction in FcgammaRIIA tyrosine phosphorylation that accompanies this inhibition. Significantly, tyrosine phosphorylation of Syk kinase is substantially inhibited by SHP-1. Furthermore, the activation of SHP-1 tyrosine phosphorylation is observed following stimulation of FcgammaRII in COS-1 cells and in human monocytes. The SH2 domain containing inositol phosphatase (SHIP), SHIP-1 also enhances FcgammaRIIB-mediated inhibition of FcgammaRIIA, indicating that FcgammaRIIB can use more than one pathway for its inhibitory action. In addition, SHP-1 and SHIP-1 can inhibit FcgammaRIIA phagocytosis and signal transduction in the absence of FcgammaRIIB. The data support emerging evidence that SH2-containing phosphatases, such as SHP-1 and SHIP-1, can modulate signaling by "activating" receptors.
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Affiliation(s)
- Zhen-Yu Huang
- University of Pennsylvania School of Medicine, Philadelphia 19104, USA
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104
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Galandrini R, Tassi I, Mattia G, Lenti L, Piccoli M, Frati L, Santoni A. SH2-containing inositol phosphatase (SHIP-1) transiently translocates to raft domains and modulates CD16-mediated cytotoxicity in human NK cells. Blood 2002; 100:4581-9. [PMID: 12393695 DOI: 10.1182/blood-2002-04-1058] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Membrane recruitment of the SH2-containing 5' inositol phosphatase 1 (SHIP-1) is responsible for the inhibitory signals that modulate phosphatidylinositol 3-kinase (PI3K)-dependent signaling pathways. Here we have investigated the molecular mechanisms underlying SHIP-1 activation and its role in CD16-mediated cytotoxicity. We initially demonstrated that a substantial fraction of SHIP-1-mediated 5' inositol phosphatase activity associates with CD16 zeta chain after receptor cross-linking. Moreover, CD16 stimulation on human primary natural killer (NK) cells induces the rapid and transient translocation of SHIP-1 in the lipid-enriched plasma membrane microdomains, termed rafts, where it associates with tyrosine-phosphorylated zeta chain and shc adaptor protein. As evaluated by confocal microscopy, CD16 engagement by reverse antibody-dependent cellular cytotoxicity (ADCC) rapidly induces SHIP-1 redistribution toward the area of NK cell contact with target cells and its codistribution with aggregated rafts where CD16 receptor also colocalizes. The functional role of SHIP-1 in the modulation of CD16-induced cytotoxicity was explored in NK cells infected with recombinant vaccinia viruses encoding wild-type or catalytic domain-deleted mutant SHIP-1. We found a significant SHIP-1-mediated decrease of CD16-induced cytotoxicity that is strictly dependent on its catalytic activity. These data demonstrate that CD16 engagement on NK cells induces membrane targeting and activation of SHIP-1, which acts as negative regulator of ADCC function.
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Affiliation(s)
- Ricciarda Galandrini
- Department of Experimental Medicine and Pathology, Istituto Pasteur-Fondazione Cenci Bolognetti, University La Sapienza, Rome, Italy
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105
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García‐García E, Rosales C. Signal transduction during Fc receptor‐mediated phagocytosis. J Leukoc Biol 2002. [DOI: 10.1189/jlb.72.6.1092] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [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
| | - Carlos Rosales
- Immunology Department, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City
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106
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Abstract
We present a hypothesis regarding the mode of induction of the inhibitory phosphatases SHP-1 and SHIP in hematopoietic cells. One mode is a general one in which the phosphatase regulates but does not abort signal transduction and biology. Regulator phosphatases are induced by directly or indirectly engaging the amino acid motifs present in the activating receptor, and act to control the biochemical and biological output. The other mode of induction is a specific one, which critically involves paired co-clustering of activating and inhibitory receptors. Phosphatases working in this way act only under conditions of paired co-clustering of activating and inhibitory receptors, and directly bind amino acid motifs present in the inhibitory receptor. However, this mode of induction is apparently more efficient, as cellular activation is completely aborted. This review presents several examples of each mode of inhibition and speculates on their mechanisms.
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Affiliation(s)
- K M Coggeshall
- The Oklahoma Medical Research Foundation, Program in Immunobiology, 825 N.E. 13th St., Oklahoma City, OK 73104, USA.
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107
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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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108
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Tridandapani S, Wang Y, Marsh CB, Anderson CL. Src homology 2 domain-containing inositol polyphosphate phosphatase regulates NF-kappa B-mediated gene transcription by phagocytic Fc gamma Rs in human myeloid cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 169:4370-8. [PMID: 12370370 DOI: 10.4049/jimmunol.169.8.4370] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
FcgammaR-mediated phagocytosis is accompanied by the generation of tissue-damaging products such as inflammatory cytokines and reactive oxygen species. Hence, the phagocytic response must be a tightly regulated process. Recent studies have established that clustering FcgammaR on human myeloid cells causes tyrosine phosphorylation of Src homology 2 domain-containing inositol polyphosphate phosphatase (SHIP). However, it is not known how these immunoreceptor tyrosine-based activation motif (ITAM)-bearing phagocytic FcgammaR activate SHIP, or whether the activation of SHIP by ITAMs has any functional relevance. Experiments addressing the mechanism of SHIP association with ITAMs have been done in in vitro systems using phosphopeptides. In this study we undertook to dissect the molecular mechanism by which SHIP associates with the native ITAM-FcgammaR and becomes phosphorylated. In this report we provide evidence that first, SHIP is indeed phosphorylated by ITAM-FcgammaR, using cell systems that lack FcgammaRIIb expression; second, coimmunoprecipitation experiments demonstrate that SHIP associates with native ITAM-bearing FcgammaRIIa in vivo; and third, phosphorylation of SHIP by FcgammaRIIa is inhibited by overexpressing either the SHIP Src homology 2 domain or a dominant negative mutant of Shc. In contrast, SHIP phosphorylation was not inhibited by a dominant negative mutant of Grb2. We extend these observations to show that SHIP activation by ITAM-FcgammaR down-regulates NF-kappaB-induced gene transcription. These findings both provide a molecular mechanism for SHIP association with native ITAM-bearing receptors and demonstrate that SHIP association with ITAM-FcgammaR serves to regulate gene expression during the phagocytic process.
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Affiliation(s)
- Susheela Tridandapani
- Department of Internal Medicine, Heart and Lung Research Institute, Room 405D, Ohio State University, 473 West Twelfth Avenue, Columbus, OH 43210, USA.
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109
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Cox D, Berg JS, Cammer M, Chinegwundoh JO, Dale BM, Cheney RE, Greenberg S. Myosin X is a downstream effector of PI(3)K during phagocytosis. Nat Cell Biol 2002; 4:469-77. [PMID: 12055636 DOI: 10.1038/ncb805] [Citation(s) in RCA: 181] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Phagocytosis is a phosphatidylinositol-3-OH-kinase (PI(3)K)-dependent process in macrophages. We identified Myo10 (Myosin-X), an unconventional myosin with pleckstrin homology (PH) domains, as a potential downstream target of PI(3)K. Myo10 was recruited to phagocytic cups in a wortmannin-sensitive manner. Expression of a truncation construct of Myo10 (Myo10 tail) in a macrophage cell line or cytosolic loading of anti-Myo10 antibodies in bovine alveolar macrophages inhibited phagocytosis. In contrast, expression of a Myo10 tail construct containing a point mutation in one of its PH domains failed to inhibit phagocytosis. Expression of Myo10 tail inhibited spreading, but not adhesion, on IgG-coated substrates, consistent with a function for Myo10 in pseudopod extension. We propose that Myo10 provides a molecular link between PI(3)K and pseudopod extension during phagocytosis.
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Affiliation(s)
- Dianne Cox
- Department of Medicine, Columbia University, 630 West 168th Street, New York, NY 10032, USA
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110
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Abstract
Immune cells are activated as a result of productive interactions between ligands and various receptors known as immunoreceptors. These receptors function by recruiting cytoplasmic protein tyrosine kinases, which trigger a unique phosphorylation signal leading to cell activation. In the recent past, there has been increasing interest in elucidating the processes involved in the negative regulation of immunoreceptor-mediated signal transduction. Evidence is accumulating that immunoreceptor signaling is inhibited by complex and highly regulated mechanisms that involve receptors, protein tyrosine kinases, protein tyrosine phosphatases, lipid phosphatases, ubiquitin ligases, and inhibitory adaptor molecules. Genetic evidence indicates that this inhibitory machinery is crucial for normal immune cell homeostasis.
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Affiliation(s)
- André Veillette
- Laboratory of Molecular Oncology, IRCM, 110 Pine Avenue West, Montréal, Québec, Canada H2W 1R7.
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111
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Abstract
The phagocytic response of innate immune cells such as macrophages is defined by the activation of complex signaling networks that are stimulated by microbial contact. Many individual proteins have been demonstrated to participate in phagocytosis, and the application of high-throughput tools has indicated that many more remain to be described. In this review, we examine this complexity and describe how during recognition, multiple receptors are simultaneously engaged to mediate internalization, activate microbial killing, and induce the production of inflammatory cytokines and chemokines. Many signaling molecules perform multiple functions during phagocytosis, and these molecules are likely to be key regulators of the process. Indeed, pathogenic microorganisms target many of these molecules in their attempts to evade destruction.
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Affiliation(s)
- David M Underhill
- Institute for Systems Biology, 1441 North 34 Street, Seattle, Washington 98103, USA.
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112
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Abstract
Through selective disruption of phosphoinositide 3-kinase (PI3K) activity and the use of green fluorescent protein tagged derivatives of domains capable of specifically binding the lipid products of PI3Ks in vivo, it has been shown that this family of signalling enzymes have vital and distinct roles in chemotaxis, phagocytosis and phagosome maturation in leukocytes.
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Affiliation(s)
- Len Stephens
- The Babraham Institute, Babraham, Cambridge CB2 4AT, UK.
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113
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Abstract
Multiple lines of experimental data indicate that SHIP1 is an important negative regulator of the immune system. SHIP1 has been demonstrated to control survival and proliferation, as well as differentiation. In the cases of some inhibitory receptors, such as Fc gamma RIIB1, the molecular mechanisms of control by SHIP1 are established. For other receptors, particularly activating receptors where SHIP1 appears to set activation thresholds, the mechanisms remain to be discovered. Further study on SHIP and other SHIP family members could be critical for our understanding the negative regulation in multiple hematopoietic lineages and the immune system as a whole.
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Affiliation(s)
- Michael E March
- Beirne B. Carter Center for Immunology Research and the Department of Microbiology, University of Virginia, Charlottesville, VA 22908, USA
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114
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Abstract
Phagocytosis is an evolutionarily conserved process utilized by many cells to ingest microbial pathogens, and apoptotic and necrotic corpses. Recent investigation has revealed a fundamental requirement for two co-ordinated cellular processes--cytoskeletal alterations and membrane trafficking--in the phagocytic event. Some elements of this machinery are co-opted by certain pathogens to gain entry into host cells.
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Affiliation(s)
- Steven Greenberg
- Columbia University, Departments of Medicine and Pharmacology/BB914, 630 West 168th Street, New York, NY 10032, USA.
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115
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Kim JS, Peng X, De PK, Geahlen RL, Durden DL. PTEN controls immunoreceptor (immunoreceptor tyrosine-based activation motif) signaling and the activation of Rac. Blood 2002; 99:694-7. [PMID: 11781256 DOI: 10.1182/blood.v99.2.694] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fcgamma receptor-mediated phagocytosis is a model for the study of immunoreceptor (immunoreceptor tyrosine-based activation motif [ITAM]) signaling and involves the activation of protein tyrosine kinases, protein tyrosine phosphatases, and downstream effectors including phosphatidylinositol-3 (PI-3) kinase. Relatively little is known of the role of lipid phosphatases in the control of ITAM signaling and inflammation. A heterologous COS7 cell system was used to examine the roles played by PI-3 kinase and the dual-specificity phosphatase, phosphatase and tensin homolog deleted on chromosome 10 (PTEN), in the signal transduction pathway leading to Fcgamma receptor IIA-mediated phagocytosis and the activation of Rac. The expression of wildtype PTEN completely abrogated the phagocytosis of immunoglobulin-G-sensitized sheep red blood cells, as compared with the catalytically inactive mutant of PTEN, which had no effect. This is the first direct evidence that PTEN, an inositol 3' phosphatase, regulates Fcgamma receptor-mediated phagocytosis, an ITAM-based signaling event. The data suggest that PTEN exerts control over phagocytosis potentially by controlling the downstream conversion of guanosine diphosphate-Rac to guanosine triphosphate-Rac following ITAM stimulation.
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Affiliation(s)
- Jong Suk Kim
- Department of Pediatrics, Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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116
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Cox D, Greenberg S. Phagocytic signaling strategies: Fc(gamma)receptor-mediated phagocytosis as a model system. Semin Immunol 2001; 13:339-45. [PMID: 11708889 DOI: 10.1006/smim.2001.0330] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Phagocytosis is a phylogenetically ancient process by which eukaryotic cells engulf insoluble substances whose size exceeds approximately 0.5 microm. The engulfment process requires the concerted action of several fundamental cellular pathways and is governed by multiple transmembrane signaling events. Here we focus on phagocytosis mediated by a well-studied class of phagocytic receptors that recognize the Fc portion of IgG (Fc(gamma)Rs ).
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Affiliation(s)
- D Cox
- Department of Medicine, Columbia University, 630 West 168th Street, New York, NY 10032, USA.
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117
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Abstract
Engulfment of particles by phagocytes involves remodeling of the plasma membrane. We review recent work that suggests that focal exocytosis of endomembranes plays an important role in pseudopod extension during phagocytosis.
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Affiliation(s)
- J W Booth
- Programme in Cell Biology, Hospital for Sick Children, 555 University Avenue, Toronto, Ontario M5X 1G8, Canada
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118
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Cullen PJ, Cozier GE, Banting G, Mellor H. Modular phosphoinositide-binding domains--their role in signalling and membrane trafficking. Curr Biol 2001; 11:R882-93. [PMID: 11696348 DOI: 10.1016/s0960-9822(01)00523-1] [Citation(s) in RCA: 150] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The membrane phospholipid phosphatidylinositol is the precursor of a family of lipid second-messengers, known as phosphoinositides, which differ in the phosphorylation status of their inositol group. A major advance in understanding phosphoinositide signalling has been the identification of a number of highly conserved modular protein domains whose function appears to be to bind various phosphoinositides. Such 'cut and paste' modules are found in a diverse array of multidomain proteins and recruit their host protein to specific regions in cells via interactions with phosphoinositides. Here, with particular reference to proteins involved in membrane traffic pathways, we discuss recent advances in our understanding of phosphoinositide-binding domains.
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Affiliation(s)
- P J Cullen
- Inositide Group, Integrated Signalling Laboratories, Department of Biochemistry, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, UK.
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119
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Ellson CD, Anderson KE, Morgan G, Chilvers ER, Lipp P, Stephens LR, Hawkins PT. Phosphatidylinositol 3-phosphate is generated in phagosomal membranes. Curr Biol 2001; 11:1631-5. [PMID: 11676926 DOI: 10.1016/s0960-9822(01)00447-x] [Citation(s) in RCA: 141] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Phagocytic cells such as neutrophils and macrophages engulf and destroy invading microorganisms. After internalization, material captured within the phagosomal membrane is destroyed by a complex process of coordinated delivery of digestive enzymes and reactive oxygen species. Several endosomal, lysosomal, and oxidase components expected to participate in these events have recently been shown to bind PtdIns3P, suggesting that this lipid may play a role in this process. We used live, digital fluorescence imaging of RAW 264.7 cells stably expressing either a PtdIns3P binding GFP-PX domain or a GFP-FYVE domain to visualize changes in the levels and subcellular localization of PtdIns3P during phagocytic uptake of IgG-opsonized zymosan particles. Very similar results were obtained using both PtdIns3P probes. The basal distribution of each PtdIns3P probe was partially cytosolic and partially localized to EEA-1-positive endosomal structures. Within about 2-3 min of zymosan attachment and concomitant with the closure of the phagosomal membrane, GFP-positive vesicles moved toward and attached to a localized area of the phagosome. A dramatic, transient accumulation of GFP probe around the entire phagosome rapidly ensued, accompanied by a transient drop in cytosolic GFP fluorescence. The magnitude and timing of this rise in PtdIns3P clearly suggest that it is an ideal candidate for controlling the early stages of phagosomal maturation.
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Affiliation(s)
- C D Ellson
- Inositide Laboratory, The Babraham Institute, Babraham, CB2 4AT, Cambridge, United Kingdom
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120
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Galandrini R, Tassi I, Morrone S, Lanfrancone L, Pelicci P, Piccoli M, Frati L, Santoni A. The adaptor protein shc is involved in the negative regulation of NK cell-mediated cytotoxicity. Eur J Immunol 2001. [DOI: 10.1002/1521-4141(200107)31:7<2016::aid-immu2016>3.0.co;2-w] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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121
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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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122
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Abstract
Rho proteins and phosphatidylinositide 3-kinases (PI 3-kinases) have been widely implicated in regulating cell motility both in cultured cells and in animal models. Monocytes are recruited from the bloodstream in response to inflammatory signals, and migrate across the endothelial barrier into the tissues, where they differentiate into macrophages and phagocytose bacteria and cells. Studies of monocytes and macrophages have revealed that different Rho family members and PI 3-kinases are not functionally redundant but play unique and distinct roles in motile responses.
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Affiliation(s)
- A J Ridley
- Ludwig Institute for Cancer Research, Royal Free and University College School of Medicine, London, UK.
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123
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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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