 Direct interactions between mutants of Jak3 and Shc showed that while FERM domain of Jak3 was sufficient for binding to Shc, CH-1 and PID domains of Shc were responsible for binding to Jak3.Functionally, Jak3 was auto-phosphorylated under IL-2 stimulation in epithelial cells.However, Shc recruited tyrosine phosphatase SHP-2 and PTP-1B to Jak3 and thereby dephosphorylate Jak3.