| First Author | Sillman AL | Year | 1995 |
| Journal | J Biol Chem | Volume | 270 |
| Issue | 20 | Pages | 11806-11 |
| PubMed ID | 7744830 | Mgi Jnum | J:25526 |
| Mgi Id | MGI:73242 | Doi | 10.1074/jbc.270.20.11806 |
| Citation | Sillman AL, et al. (1995) Association of p72syk with the src homology-2 (SH2) domains of PLC gamma 1 in B lymphocytes. J Biol Chem 270(20):11806-11 |
| abstractText | Phospholipase C gamma-catalyzed inositol phospholipid hydrolysis, a critical step in B cell antigen receptor signaling leading to second messenger generation and proliferation, depends upon tyrosine kinase activation. The B cell antigen receptor-associated tyrosine kinases p53/56lyn, p59fyn, p55blk, and p72syk are assumed to participate in receptor-initiated signaling. It is unknown, however, which of these kinases is involved in the tyrosine phosphorylation and resulting activation of phospholipase C gamma in response to antigen receptor cross-linking. We have used a fusion protein containing the tandem src homology-2 (SH2) domains of phospholipase C gamma 1 (PLC gamma 1) to identify B cell kinases which associate with PLC gamma 1. Using an in vitro kinase assay, we demonstrate SH2-dependent association of tyrosine kinase activity from anti-mu-stimulated B cells. The PLC gamma 1 SH2 domains associate with a prominent 70-72-kDa tyrosine phosphoprotein from anti-mu-stimulated, but not resting, B cells. Immunoblotting and secondary immunoprecipitation studies definitively identify this protein as p72syk. These results imply a physical interaction between PLC gamma 1 and p72syk in antigen receptor-stimulated B cells. This conclusion is confirmed by our ability to co-immunoprecipitate p72syk and PLC gamma 1 from lysates of anti-mu-stimulated B cells. These results implicate p72syk in the activation of phospholipase C gamma 1 during B cell antigen receptor signaling. |
