Mitogen inactivation of glycogen synthase kinase-3 beta in intact cells via serine 9 phosphorylation.

摘要: Glycogen synthase kinase-3 (GSK-3), a protein-serine kinase implicated in cell-fate determination and differentiation, phosphorylates several regulatory proteins that are activated by dephosphorylation response to hormones or growth factors. GSK-3 beta is phosphorylated vitro at serine 9 p70 S6 p90rsk-1, resulting its inhibition [Sutherland, Leighton, Cohen (1993) Biochem. J. 296, 15-19]. Using HeLa cells expressing mutant containing alanine residue 9, we demonstrate modified intact targeted specifically phosphorylation leads loss of activity. Since p90rsk-1 directly mitogen-activated protein kinases, agonists this pathway, such as insulin, repress function.