Structural characteristics and interacting proteins of p130cas. (A). p130Cas is a nonezymatic scaffolding protein that contains, (i) an N-terminal SH3 domain that binds FAK and Pyk2, 15 repeats of a YxxP motif, a serine-rich motif that binds Src kinases, and a conserved C-terminal region that binds members of the Chat family of proteins. (B). Signal transduction by the p130Cas scaffold protein. The central substrate region of p130Cas (shown in panel B as a compressed configuration) is activated by mechanical force and "extension" of the central region (C). This would activate Src, induce tyrosine phosphorylation of the repetitive YxxP motifs, and recruit Crk through its SH2 domain. Further, by recruiting different proteins via the CrkSH3N, this signaling strategy would spatially integrate divergent signals, for example, after the recruitment of various GTPase pathways such as DOCK1, SOS, and C3G.