title: Superclustering of B cell receptor and Fc gamma RIIB1 activates Src homology 2-containing protein tyrosine phosphatase-1.
abstract: Fc gamma RIIB1 (CD32) is a receptor that binds the Fc domain of Ag-complexed IgG. Coaggregation of B cell receptor (BCR) and Fc gamma RIIB1 generates a dominant negative signal that inhibits B cell activation. In Ag-specific Id-positive B cells, the co-cross-linking of BCR and Fc gamma RIIB1 by anti-Id Ab resulted in the association of both Src homology 2-containing protein tyrosine phosphatase (SHP-1) and Src homology 2-containing inositol phosphatase (SHIP) with the Fc gamma RIIB1; however, only SHIP activity was detected. "Superclustering" of the BCR and Fc gamma RIIB1 complex induced by stimulation with anti-Id Ab plus polyvalent Ag synergistically activated SHP-1. The degree of co-cross-linking between BCR and Fc gamma RIIB1 may determine the activation status of SHP-1 and SHIP.
authors.affiliation: The John P. Robarts Research Institute, Department of Microbiology and Immunology, University of Western Ontario, London, Canada.
authors.forename: K
authors.initials: K
authors.lastname: Sato
authors.forename: A
authors.initials: A
authors.lastname: Ochi
mesh_terms: D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000494:pharmacology; D004789:Enzyme Activation / Q000276:immunology; D006241:Haptens / Q000235:genetics; D047908:Intracellular Signaling Peptides and Proteins; D016393:Lymphoma, B-Cell / Q000276:immunology / Q000378:metabolism; D051379:Mice; D010766:Phosphorylation; D054645:Protein Phosphatase 1; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011940:Receptor Aggregation / Q000276:immunology*; D011947:Receptors, Antigen, B-Cell / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D017452:Receptors, IgG / Q000378:metabolism* / Q000502:physiology; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases; D012710:Serum Albumin, Bovine / Q000235:genetics / Q000276:immunology; D015398:Signal Transduction / Q000276:immunology; D014162:Transfection / Q000276:immunology; D014301:Trinitrobenzenes / Q000276:immunology; D014407:Tumor Cells, Cultured; D018909:src Homology Domains / Q000276:immunology*
chemical_list: D000888:Antibodies, Anti-Idiotypic; D006241:Haptens; D047908:Intracellular Signaling Peptides and Proteins; D011947:Receptors, Antigen, B-Cell; D017452:Receptors, IgG; D014301:Trinitrobenzenes; C038601:trinitrophenyl-bovine serum albumin; D012710:Serum Albumin, Bovine; D054645:Protein Phosphatase 1; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; C516725:Ptpn11 protein, mouse; C509248:Ptpn6 protein, mouse; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases