title: G protein coupling of antigen receptor-stimulated polyphosphoinositide hydrolysis in B cells.
abstract: Cross-linking of the IgM and IgD Ag-R on mature B lymphocytes provokes the rapid hydrolysis of phosphatidylinositol 4,5-bisphosphate. We show here that in permeabilized, [3H]inositol-labeled mouse B cells the nonhydrolyzable GTP analogue GTP gamma S induces release of inositol phosphates, including inositol trisphosphate. The response is markedly augmented by the addition of polyclonal anti-Ig or anti-mu or anti-delta mAb. Inositol phosphate release provoked in intact B cells by any of the anti-receptor antibodies was not inhibited by pertussis toxin and only partially inhibited by cholera toxin. The results therefore indicate that both IgM- and IgD-R on B cells are coupled to the polyphosphoinositide-specific phosphodiesterase by one or more G proteins, which have yet to be identified.
authors.affiliation: National Institute for Medical Research, London, England.
authors.forename: M M
authors.initials: MM
authors.lastname: Harnett
authors.forename: G G
authors.initials: GG
authors.lastname: Klaus
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000502:physiology*; D002772:Cholera Toxin / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000502:physiology*; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D006801:Humans; D007072:Immunoglobulin D / Q000502:physiology; D007075:Immunoglobulin M / Q000502:physiology; D051379:Mice; D037342:Pertussis Toxin; D010716:Phosphatidylinositols / Q000378:metabolism*; D054801:Phosphoinositide Phospholipase C; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D011947:Receptors, Antigen, B-Cell / Q000502:physiology*; D013873:Thionucleotides / Q000494:pharmacology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
chemical_list: D007072:Immunoglobulin D; D007075:Immunoglobulin M; D010716:Phosphatidylinositols; D011947:Receptors, Antigen, B-Cell; D013873:Thionucleotides; D010566:Virulence Factors, Bordetella; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate; D002772:Cholera Toxin; D037342:Pertussis Toxin; D010727:Phosphoric Diester Hydrolases; D054801:Phosphoinositide Phospholipase C; D019204:GTP-Binding Proteins