Glycogen synthase kinase-3beta is tyrosine-phosphorylated by MEK1 in human skin fibroblasts.
Glycogen synthase kinase-3beta (GSK-3beta) can be associated with several proteins in cell. We analyzed the immunoprecipitates by an anti-GSK-3beta antibody from cell lysate of human fibroblasts and found that this protein was co-precipitated with mitogen-activated protein kinase kinase (MEK1/2). U0126, a MEK1/2 inhibitor, inhibited tyrosine phosphorylation of GSK-3beta, suggesting that MEK1/2 was involved in the phosphorylation of Tyr(216) in GSK-3beta. In vitro kinase assay was carried out using a recombinant human active MEK1 and we found that GSK-3beta was phosphorylated on Tyr(216) by this kinase in a dose- and time-dependent manner. Further, the pretreatment of fibroblasts with U0126 inhibited serum-induced nuclear translocation of GSK-3beta. These results suggested that MEK1/2 induces tyrosine phosphorylation of GSK-3beta and this cellular event might induce nuclear translocation of GSK-3beta. This is the first report to suggest that MEK1/2 phosphorylates not only ERK1/2 but also GSK-3beta.
Takahashi-Yanaga
Fumi
F
Department of Clinical Pharmacology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan. yanaga@clipharm.med.kyushu-u.ac.jp
Shiraishi
Fumie
F
Hirata
Masato
M
Miwa
Yoshikazu
Y
Morimoto
Sachio
S
Sasaguri
Toshiyuki
T
D021581:Active Transport, Cell Nucleus / Q000187:drug effects; D002070:Butadienes / Q000494:pharmacology; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000187:drug effects / Q000201:enzymology*; D038362:Glycogen Synthase Kinase 3 / Q000737:chemistry / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009570:Nitriles / Q000494:pharmacology; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D012867:Skin / Q000166:cytology; D014443:Tyrosine / Q000378:metabolism*
D002070:Butadienes; D004791:Enzyme Inhibitors; D009570:Nitriles; C113580:U 0126; D014443:Tyrosine; C482128:MAP2K2 protein, human; D011505:Protein-Tyrosine Kinases; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; D038362:Glycogen Synthase Kinase 3; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; C482125:MAP2K1 protein, human; D020929:Mitogen-Activated Protein Kinase Kinases