Sorbin And SH3 Domain Containing Protein 1 (SORBS1)

The protein product of the CBL protooncogene is prominently tyrosine phosphorylated in response to insulin in 3T3-L1 adipocytes but not in 3T3-L1 fibroblasts. After insulin-dependent tyrosine phosphorylation, CBL specifically associates with endogenous CRK and FYN. The unique structure of Cap includes 3 adjacent Src homology-3 (SH3) domains in the C terminus and a region showing significant sequence similarity with the peptide hormone sorbin. Both Cap mRNA and proteins were expressed predominantly in 3T3-L1 adipocytes and not in 3T3-L1 fibroblasts. By Northern blot analysis of mouse tissues, Cap expression was detected in greatest abundance in heart, liver, skeletal muscle, and kidney; lesser amounts were detected in brain and lung, and expression in spleen and testis was not detected.