| Identification of two tyrosine phosphoproteins , pp 70 and pp 68 , which interact with phospholipase Cgamma , Grb 2 , and Vav after B cell antigen receptor activation . ^^^ In contrast , the interaction of pp 70 and pp 68 with Grb 2 requires cooperative binding of the SH 2 and SH 3 domains of Grb 2 . ^^^ Western blot analysis demonstrated that neither pp 70 nor pp 68 represented the recently described linker protein SLP 76 , which binds Grb 2 , PLC , and Vav in T cells after T cell receptor activation . ^^^ |