Interleukin 2-induced activation of JAK3: Possible involvement in signal transduction for c-myc induction and cell proliferation

We have investigated the role of JAK3 in interleukin 2 (IL-2)-induced signal transduction with a human T cell line, ED40515(-), lacking expression of the IL-2 receptor γ chain and its sublines transfected with wild-type or mutant cDNAs of the IL-2 receptor γ chain. Our results demonstrated that the membrane-proximal cytoplasmic region, encompassing the src homology region 2 (SH2)-like subdomain, of the γ chain is essential for association and activation of JAK3. Furthermore, IL-2-induced activation of JAK3 paralleled induction of the c-myc gene and DNA synthesis but not induction of the c-fos and c-jun genes. These results support the hypothesis that JAK3 plays a pivotal role in the IL-2 receptor-mediated signals for cell growth.