Acetylation within the N- and C-terminal domains of Src regulate distinct roles of STAT3-mediated tumorigenesis

Post-translational modifications of mammalian c-Src N-terminal and C-terminal domains regulate distinct functions: myristoylation of G2 controls its cell membrane association and phosphorylation of Y419/Y527 controls its activation or inactivation, respectively. We provide evidence that Src-cell membrane association-dissociation and catalytic activation-inactivation are both regulated by acetylation. In EGF-treated cells, CREB binding protein (CBP) acetylated an N-terminal lysine cluster (K5, K7, and K9) of c-Src to promote dissociation from the cell membrane. CBP also acetylated the C-terminal K401, K423, and K427 of c-Src to activate intrinsic kinase activity for STAT3 recruitment and activation. N-terminal domain phosphorylation (Y14, Y45, and Y68) of STAT3 by c-Src activated transcriptionally active dimers of STAT3. Moreover, acetyl-Src translocated into nuclei where it formed the Src-STAT3 enhanceosome for gene regulation and cancer cell proliferation. Thus, c-Src acetylation in the N-terminal and C-terminal domains play distinct roles in Src activity and regulation.

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