The Jak-STAT pathway

A variety of important cellular functions are regulated by cytokines, The J ak-STAT pathway is one of the important signaling pathways downstream of cy tokine receptors, Following binding of a ligand to its cognate receptor, re ceptor-associated Jaks are activated. STAT proteins are then in turn activa ted by tyrosine phosphorylation by Jak kinases, allowing their dimerization and subsequent translocation into the nucleus, where they modulate express ion of target genes. Indispensable functions of Jaks and STATs in cytokine signaling in vivo have been revealed through knockout mouse studies, Moreov er, the recent discovery of the CIS/SOCS/JAB/SSI family of inhibitors has c ontributed to understanding how this pathway is negatively regulated. Publi shed by Elsevier Science Ltd.