IRS-1 binds several proteins containing Src homology 2 domains through its multiple tyrosine phosphorylation sites.

We have cloned a novel adapter protein containing Src homology 2 and Src homology 3 domains similar to the Src family of tyrosine kinases.

Pro-630 and its adjacent amino acids are conserved in all Stat family members but are absent in other proteins that contain Src homology 2 domains.