Adapter protein which may play a role in the regulation of apoptosis in response to PDGF. Interacts with phosphorylated 'Tyr-720' of PDGFRA via its SH2 domain. Expressed in skeletal muscle, brain, liver, prostate, testis, ovary, small intestine and colon. May become phosphorylated upon binding to PDGFRA. The sequence described in PubMed:11095946 is over-extended by 57 aa at the N-terminus due to the presence of an uncorrected 5' mismatch compared to the reference genome sequence.