Src homology 2 domain deletion mutants of p60v-src do not phosphorylate cellular proteins of 120-150 kDa.

We have constructed seven deletions in the src homology 2 (SH2) domain of the Rous sarcoma virus src gene and have expressed them and wild-type v-src (wt v-src) in Rat 1 fibroblasts. Transfected cells containing mutant DNAs have reduced focus forming activity when compared to cells containing the wt v-src DNA. In most cases, established cell lines that express these mutants have altered growth properties in soft agar. The src proteins isolated from mutant cell lines have reduced tyrosine kinase activity. We also see differences in the phosphorylation of cellular proteins in vivo. Unlike the wt protein kinase, the SH2 domain mutant kinases do not phosphorylate a set of cellular proteins ranging in size from 120-150 kDa.