tailieunhanh - Báo cáo khoa học: Regulation of STAT signalling by proteolytic processing Lisa Hendry and Susan John

Interaction of cytokines with their cognate receptors leads to the activation of latent transcription factors, the signal transducer and activator of transcription (STAT) proteins. Numerous studies have identified the critical roles played by STAT proteins in regulating cell proliferation, differ-entiation and survival. Consequently, the activity of STAT proteins is negatively regulated by a variety of different mechanisms, which include alternative splicing, covalent modifications, protein–protein interactions with negative regulatory proteins and proteolytic processing by pro-teases | Eur. J. Biochem. 271 4613-4620 2004 FEBS 2004 doi MINIREVIEW Regulation of STAT signalling by proteolytic processing Lisa Hendry and Susan John Peter Gorer Department of Immunobiology Programme in Infection and Immunity King s College London UK Interaction of cytokines with their cognate receptors leads to the activation of latent transcription factors the signal transducer and activator of transcription STAT proteins. Numerous studies have identified the critical roles played by STAT proteins in regulating cell proliferation differentiation and survival. Consequently the activity of STAT proteins is negatively regulated by a variety of different mechanisms which include alternative splicing covalent modifications protein-protein interactions with negative regulatory proteins and proteolytic processing by proteases. Cleavage of STAT proteins by proteases results in the generation of C-terminally truncated proteins called STATy which lack the transactivation domain and behave as functional dominant-negative proteins. Currently STATy isoforms have been identified for Stat3 Stat5a Stat5b and Stat6 in different cellular contexts and biological processes. Evidence is mounting for the role of as yet unidentified serine proteases in the proteolytic processing of STAT proteins although at least one cysteine protease calpain is also known to cleave these STATs in platelets and mast cells. Recently studies of acute myeloid leukaemia and cutaneous T cell lymphoma patients have revealed important roles for the aberrant expression of Stat3y and Stat5y proteins in the pathology of these diseases. Together these findings indicate that proteolytic processing is an important mechanism in the regulation of STAT protein biological activity and provides a fertile area for future studies. Introduction The Janus kinase-signal transducer and activator of transcription JAK-STAT signalling pathway first identified for the interferon-a b and y receptors is .