A novel signaling molecule, p130, forms stable complexes in vivo with v-Crk and v-Src in a tyrosine phosphorylation-dependent manner.

Abstract

p47v‐crk (v‐Crk), a transforming gene product containing Src homology (SH)‐2 and ‐3 domains, induces an elevated level of tyrosine phosphorylation of several cellular proteins. Among these proteins, a 125‐135 kDa protein (p130) shows marked phosphorylation at tyrosines and tight association with v‐Crk, suggesting a direct signal mediator of v‐Crk. Here we report the molecular cloning of rat p130 by immunoaffinity purification. The p130 is a novel SH3‐containing signaling molecule with a cluster of multiple putative SH2‐binding motifs of v‐Crk. Immunochemical analyses revealed that p130 is highly phosphorylated at tyrosines during transformation by p60v‐src (v‐Src), as well as by v‐Crk, forming stable complexes with these oncoproteins. The p130 behaves as an extremely potent substrate of kinase activity included in the complexes and it is a major v‐Src‐associated substrate of the Src kinase by partial peptidase mapping. Subcellular fractionation demonstrated that the cytoplasmic p130 could move to the membrane upon tyrosine phosphorylation. The p130 (designated Cas for Crk‐associated substrate) is a common cellular target of phosphorylation signal via v‐Crk and v‐Src oncoproteins, and its unique structure indicates the possible role of p130Cas in assembling signals from multiple SH2‐containing molecules.

Identification of Tyr-762 in the platelet-derived growth factor α-receptor as the binding site for Crk proteins

“…Boxes show the positions of the SH2 and SH3 domains Tyrosine phosphorylated components of 120 ± 130 kDa were constitutively coprecipitated with Crk proteins (Figure 3b and c). Reprobing of the same blots with an antiserum against p130Cas (Sakai et al, 1994) revealed that at least a component of the bands corresponds to p130Cas (data not shown). However, the identity of the other components remain unclear.…”

“…The presence of both SH2 and SH3 domains in Crk proteins is of crucial importance for their function as adaptor molecules (Tanaka et al, 1993(Tanaka et al, , 1995. The SH2 domains of Crk molecules have been shown to bind to several phosphorylated proteins, including p130Cas, Cbl and the focal adhesion protein paxillin Buday et al, 1996;Ribon et al, 1996;Sakai et al, 1994;Smit et al, 1996b). The SH3 domains have been shown to bind to e.g.…”

The substrate domain of BCAR1 is essential for anti-estrogen-resistant proliferation of human breast cancer cells

“…The BCAR1 locus was the first retroviral integration site identified and demonstrated to contain a causative gene for the resistant phenotype [8,9]. Additional experimentation demonstrated that the BCAR1 gene was the human homologue of rat p130Cas, a prominent tyrosine phosphorylated protein in Src-and Crktransformed cells, and also confirmed the dominant role of BCAR1 in tamoxifen-resistant cell growth [10][11][12]. Recently, BCAR1 has also been implicated in resistance to the chemotherapeutic drug adriamycin [13].…”

Transmembrane tyrosine phosphatase LAR induces apoptosis by dephosphorylating and destabilizing p130Cas

“…The structure of p130 Cas suggests that it may act to provide a framework for protein-protein interactions and may interact with multiple proteins. Indeed, tyrosine-phosphorylated p130 Cas has been found to bind to a number of SH2-domain-containing proteins, including Crk, Src, PI-3-kinase, Nck and PLC␥, via its distinct SH2 binding motifs (Sakai et al 1994;Burnham et al 1996;Vuori et al 1996). p130 Cas also binds to p125 FAK family proteins via its SH3 domain Burnham et al 1996;Astier et al 1997), and to Lyn via its C-terminal proline-rich sequence .…”