title: Tyrosine phosphorylation of guanosine triphosphatase activating protein by activation via surface IgG in human B cells.
abstract: In this study, we analyzed tyrosine phosphorylation of guanosine triphosphatase (GTPase) activating protein in human B cells stimulated through surface IgG, using Western blot and immunoprecipitation. Stimulation through surface IgG induced the tyrosine phosphorylation of GTPase-activating protein (GAP) and two associated proteins, a 190-Kd protein and a 62-Kd protein, within 1 minute and in a dose-dependent manner. This tyrosine phosphorylation was blocked by Genistein (Extrasynthese, Genay, France). These data suggest that GTPase-activating protein is involved in a signal transduction pathway initiated from surface IgG in human B cells.
authors.affiliation: Department of Pediatrics/Immunology, North Shore University Hospital-Cornell University Medical College, Manhasset, NY 11030.
authors.forename: H
authors.initials: H
authors.lastname: Yagura
authors.forename: N
authors.initials: N
authors.lastname: Oyaizu
authors.forename: S
authors.initials: S
authors.lastname: Pahwa
mesh_terms: D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D020690:GTPase-Activating Proteins; D006801:Humans; D007074:Immunoglobulin G / Q000502:physiology*; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000502:physiology; D011506:Proteins / Q000378:metabolism*; D011947:Receptors, Antigen, B-Cell / Q000502:physiology*; D015398:Signal Transduction; D014443:Tyrosine / Q000378:metabolism*
chemical_list: D020690:GTPase-Activating Proteins; D007074:Immunoglobulin G; D011506:Proteins; D011947:Receptors, Antigen, B-Cell; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases