We have recently investigated the role of the adaptor protein Shb in the early events of T cell signaling and observed that Shb associates with Grb 2 , linker for activation of T cells ( LAT ) and the TCR zeta chain in Jurkat cells . ^^^ Overexpression of Src homology 2 domain defective Shb caused diminished phosphorylation of LAT and consequently the activation of mitogen activated protein kinases was decreased upon TCR stimulation . ^^^ The results indicate a role for Shb as a link between the TCR and downstream signaling events involving LAT and PLC gamma 1 and resulting in the activation of transcription of the interleukin 2 gene . . ^^^
Phosphorylation of LAT creates binding sites for the Src homology 2 ( SH 2 ) domains of other proteins , including PLC gamma 1 , Grb 2 , Gads , Grap , 3BP2 , and Shb , and indirectly binds SOS , c Cbl , Vav , SLP 76 , and Itk . ^^^