In Vivo Association of v-Abl with Shc Mediated by a Non-phosphotyrosine-dependent SH2 Interaction

• Published in: The Journal of biological chemistry 1996-03, Vol.271 (9), p.4640-4645
• Main Authors: Raffel, G D, Parmar, K, Rosenberg, N
• Format: Article
• Language: English
• Subjects: 3T3 Cells; Abelson murine leukemia virus - genetics; Animals; Binding Sites; Blotting, Western; Cell Line, Transformed; Genes, abl; Ligands; Mice; Oncogene Proteins v-abl - isolation & purification; Oncogene Proteins v-abl - metabolism; Phosphates - metabolism; Phosphoproteins - isolation & purification; Phosphoproteins - metabolism; Phosphotyrosine; Recombinant Fusion Proteins - biosynthesis; src Homology Domains
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.271.9.4640

A necessary downstream element of Abelson murine leukemia virus (Ab-MLV)-mediated transformation is Ras, which can be activated by the phosphotyrosine-dependent association of Shc with the Grb2-mSos complex. Here we show that Shc is tyrosine-phosphorylated and associates with Grb2 in v-Abl-transformed cells, whereas Shc in NIH3T3 cells is phosphorylated solely on serine and is not Grb2-associated. In addition, Shc coprecipitates with P120 v-Abl and P70 v-Abl, which lacks the carboxyl terminus. Surprisingly, a kinase-defective mutant of P120 also binds Shc, demonstrating that Shc/v-Abl association is a phosphotyrosine-independent interaction. Glutathione S -transferase fusion proteins were used to map the interacting domains and showed that Shc from both NIH3T3 and v-Abl-transformed cells binds to the Abl SH2 domain and that P120 v-Abl binds to a region in the amino terminus of Shc. Consistent with these data, a v-Abl mutant encoding only the Gag and SH2 regions was able to bind Shc in vivo . The unique non-phosphotyrosine-mediated binding of Shc may allow direct tyrosine phosphorylation of Shc by v-Abl and subsequent activation of the Ras pathway through assembly of a signaling complex with Grb2-mSos.