title: Association of activated phosphatidylinositol 3-kinase with p120cbl in antigen receptor-ligated B cells.
abstract: A 120-kDa protein that is tyrosine-phosphorylated upon antigen receptor ligation in B lymphocytes has been identified as the product of the c-cbl protooncogene. Tyrosine phosphorylation of Cbl depends on the efficient association of membrane immunoglobulin heavy chains with the Ig alpha/beta heterodimer but is unimpaired in splenic B cells from the Xid mouse. Cross-linking of membrane IgM and membrane IgG, but not of CD40, leads to the tyrosine phosphorylation of Cbl. In receptor-ligated B lymphocytes, p120cbl associates with an 85-kDa protein that has been identified as the 85-kDa subunit of phosphatidylinositol 3-kinase.
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology / Q000502:physiology*; D002460:Cell Line; D003432:Cross-Linking Reagents; D004789:Enzyme Activation; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism; D007075:Immunoglobulin M / Q000378:metabolism; D051379:Mice; D008817:Mice, Mutant Strains; D008970:Molecular Weight; D016297:Mutagenesis, Site-Directed; D019869:Phosphatidylinositol 3-Kinases; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism*; D019000:Phosphotyrosine / Q000032:analysis / Q000378:metabolism; D017354:Point Mutation; D011518:Proto-Oncogene Proteins / Q000302:isolation & purification / Q000378:metabolism*; D050721:Proto-Oncogene Proteins c-cbl; D011947:Receptors, Antigen, B-Cell / Q000378:metabolism / Q000502:physiology*; D011994:Recombinant Proteins / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases
chemical_list: D003432:Cross-Linking Reagents; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D011518:Proto-Oncogene Proteins; D011947:Receptors, Antigen, B-Cell; D011994:Recombinant Proteins; D019000:Phosphotyrosine; D050721:Proto-Oncogene Proteins c-cbl; D044767:Ubiquitin-Protein Ligases; D019869:Phosphatidylinositol 3-Kinases; D017853:Phosphotransferases (Alcohol Group Acceptor); C067419:CBL protein, human; C493849:Cbl protein, mouse