SOCS1 has been identified as a KIT binding partner from the yeast two-hybrid system (Sepulveda et al, 1999). SOCS1 expression is induced upon KIT activation. It associates with KIT via its SH2 domain. SOCS1 does not inhibit KIT kinase activity directly, instead it binds to GRB2 and VAV1, and selectively inhibits SCF-induced proliferation, while not effecting survival signal (Sepulveda et al, 1999). It has been proposed that SOCS1 may interrupt signal transduction pathways downstream of JAK2 (Sepulveda et al, 1999).