P66shc inhibits insulin-like growth factor-I signaling via direct binding to Src through its polyproline and Src homology 2 domains, resulting in impairment of Src kinase activation.

ABSTRACT: p66(shc) is increased in response to cell stress, and these increases regulate growth factor actions. These studies were conducted to determine how p66(shc) alters IGF-I-stimulated Src activation, leading to decreased IGF-I actions. Our results show that p66(shc) binds to Src through a polyproline sequence motif contained in the CH2 domain, a unique domain in p66(shc), and IGF-I stimulates this interaction. Disruption of this interaction using a synthetic peptide containing the p66(shc) polyproline domain or expression of a p66(shc) mutant containing substitutions for the proline residues (P47A/P48A/P50A) resulted in enhanced Src kinase activity, p52(shc) phosphorylation, MAPK activation, and cell proliferation in response to IGF-I. To determine the mechanism of inhibition, the full-length

SUBMITTER: Xi G 

PROVIDER: S-EPMC2844143 | biostudies-literature | 2010 Mar

REPOSITORIES: biostudies-literature