Identification of Ras GTPase-activating protein-binding sites in adaptor protein Nck-α.

Adaptor proteins consisting of Src homology (SH) 2 and 3 domains mediate various cellular signaling events initiated by receptor protein tyrosine kinases. Nck-α is one of the adaptor proteins implicated in the coordination of multiple intracellular signal transduction pathways emanating from the ligand-activated PDGF receptor-b. In our previous studies we have shown that Nck-α constantly associates with RasGTPase-activating protein (RasGAP). Here we show that SH3 do-mains of Nck-α are responsible for constitutive association with RasGAP. Moreover, Nck-α and RasGAP interact directly in vitro. These data provide a new insight into the molecular mechanism of RasGAP and Nck-α interaction. [ABSTRACT FROM AUTHOR]