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 expr ession of the IL-2 receptor gamma chain and its sublines transfected w ith wild-type or mutant cDNAs of the IL-2 receptor gamma chain. Our re sults demonstrated that the membrane-proximal cytoplasmic region, enco mpassing the src homology region 2 (SH2)-like subdomain, of the gamma chain is essential for association and activation of JAK3. Furthermore , IL-2-induced activation of JAK3 paralleled induction of the c-myc ge ne and DNA synthesis but not induction of the c-fos and c-jun genes. T hese results support the hypothesis that JAK3 plays a pivotal role in the IL-2 receptor-mediated signals for cell growth.