The Journal of Immunology · 1996 · 171 citations · 0 references
Life SciencesBiochemistryImmunologyCell SignalingProtein-protein InteractionsSignal TransductionAdaptor Protein ComplexesAdaptor ProteinsB Cell ActivationB Cell BiologyB Cell Receptor SignalingProtein Kinase CascadesAdaptor Protein RecruitmentB Cell Receptor ActivationB Cell Receptor PhosphorylationPhosphatidylinositol MetabolismProtein Tyrosine PhosphorylationReceptor Protein Tyrosine PhosphatasesTyrosine MetabolismTyrosine Phosphorylation Signaling
Stimulation of the B cell Ag receptor (BCR) has been reported to induce tyrosine phosphorylation of a 145-kDa protein and its association with the adapter protein Shc. We have identified this protein as the novel inositol polyphosphate 5-phosphatase (SHIP). Further analysis revealed that both maximal phosphorylation of SHIP and its association with Shc require co-clustering with the Fc receptor for IgG (Fc gamma RII) rather than stimulation of the BCR alone. Since co-clustering of the BCR and Fc gamma RII also down-regulates proliferation induced by Ag receptor stimulation, we hypothesize that tyrosine phosphorylation of SHIP and its association with Shc contribute to negative signaling through effects on inositol and phosphatidylinositol metabolism.