Interaction of the c-cbl proto-oncogene product with the Tyk-2 protein tyrosine kinase.

The c-cbl proto-oncogene product (p120cbl) forms a stable complex with the Tyk-2 protein tyrosine kinase in various human cell lines of diverse hematopoietic origin. In U-266 myeloma and 293T embryonic kidney cells, p120cbl is rapidly phosphorylated on tyrosine in an IFN alpha-dependent manner. p120cbl also acts as a specific substrate for the Tyk-2-associated SHP-1 phosphatase in vitro, suggesting that this phosphatase plays a regulatory role on the phosphorylation of the protein. These data provide evidence that p120cbl interacts with the functional Type I IFN receptor complex, and suggest its involvement in IFN alpha signaling.