p130Cas, a Substrate Associated with v-Src and v-Crk, Localizes to Focal Adhesions and Binds to Focal Adhesion Kinase

Abstract

p130(Cas) (crk associated substrate) has the structural characteristics of an adapter protein, containing multiple consensus SH2 binding sites, an SH3 domain, and a proline-rich domain. The structure of p130(Cas) suggests that it may act to provide a framework for protein-protein interactions; however, as yet, its functional role in cells is unknown. In this report we show that p130(Cas) is localized to focal adhesions. We demonstrate that p130(Cas) associates both in vitro and in vivo with pp125(FAK) (focal adhesion kinase), a kinase implicated in signaling by the integrin family of cell adhesion receptors. p130(Cas) also associates with pp41/43(FRNK) (pp125(FAK)-related, non-kinase), an autonomously expressed form of pp125(FAK) composed of only the C-terminal noncatalytic domain. We show that the association of p130(Cas) with pp125(Fak) and pp41/43(FRNK) is direct, and is mediated by the binding of the SH3 domain of p130(Cas) to a proline-rich sequence present in both the C terminus of pp125(FAK) and in pp41/43(FRNK). In agreement with recent studies we show that p130(Cas) is tyrosine-phosphorylated upon integrin mediated cell adhesion. The association of p130(Cas) with pp125(FAK), a kinase which is activated upon cell adhesion, is likely to be functionally important in integrin mediated signal transduction.

Crk protein binds to PDGF receptor and insulin receptor substrate-1 with different modulating effects on PDGF- and insulin-dependent signaling pathways

“…Cas forms a stable complex with v-Crk and c-Crk in a phosphorylation-dependent manner and is a substrate for Src-family kinases (Vuori et al, 1996). That Cas was phosphorylated on tyrosine in the absence of insulin can be explained by adhesion-induced tyrosine phosphorylation of Cas (Nojima et al, 1995;Vuori and Ruoslahti, 1995 was found to be tyrosine-phosphorylated in some continuously adherent cells (Harte et al, 1996;Ribon and Saltiel, 1996). We observed a decreased association of Crk with Cas after insulin treatment.…”

FAK engages multiple pathways to maintain survival of fibroblasts and epithelia – differential roles for paxillin and p130Cas

“…myrFAK was immunprecipitated with anti-V5 and immunoblotted for the coexpressed p130Cas. Deletion of PR-1, reported as the primary binding site for p130Cas (Harte et al, 1996;Polte and Hanks, 1995), resulted in a noticeable decrease in the amount of p130Cas⌬SD binding ( Fig. 5d, lane 4).…”

“…FAK contains two proline rich (PR) domains, which can interact with the SH3-domain-containing proteins (Harte et al, 1996;Hildebrand et al, 1996;Polte and Hanks, 1995). We generated myrFAK constructs lacking either or both PR domains (Fig.…”

Collagen IV regulates Caco-2 cell spreading and p130Cas phosphorylation by FAK-dependent and FAK-independent pathways

“…The SH3 domain of p130 Cas is required to rescue inhibition of cell spreading by p130 Cas siRNA p130 Cas interacts with FAK primarily via binding of its SH3 domain to the FAK proline-rich region, spanning amino acids 712 to 718 (Polte and Hanks, 1995;Harte et al, 1996), and this region is necessary for association of p130 Cas with focal adhesions in Cos-7 cells and Srctransformed NIH3T3 cells (Nakamoto et al, 1997). We sought to confirm a role for FAK signaling through p130 Cas in regulation of cell spreading by knocking out endogenous expression of p130 Cas and re-expressing either wild type or SH3 domain-deleted rat p130 Cas .…”