title: Glycogen synthase kinase 3 beta is a natural activator of mitogen-activated protein kinase/extracellular signal-regulated kinase kinase kinase 1 (MEKK1).
abstract: Glycogen synthase kinase 3beta (GSK3 beta) is implicated in many biological events, including embryonic development, cell differentiation, apoptosis, and insulin response. GSK3 beta has now been shown to induce activation of the mitogen-activated protein kinase kinase kinase MEKK1 and thereby to promote signaling by the stress-activated protein kinase pathway. GSK3 beta-binding protein blocked the activation of MEKK1 by GSK3 beta in human embryonic kidney 293 (HEK293) cells. Furthermore, co-immunoprecipitation analysis revealed a physical association between endogenous GSK3 beta and MEKK1 in HEK293 cells. Overexpression of axin1, a GSK3 beta-regulated scaffolding protein, did not affect the physical interaction between GSK3 beta and MEKK1 in transfected HEK293 cells. Exposure of cells to insulin inhibited the activation of MEKK1 by GSK3 beta, and this inhibitory effect of insulin was abolished by the phosphatidylinositol 3-kinase inhibitor wortmannin. Furthermore, MEKK1 activity under either basal or UV- or tumor necrosis factor alpha-stimulated conditions was reduced in embryonic fibroblasts derived from GSK3 beta knockout mice compared with that in such cells from wild-type mice. Ectopic expression of GSK3 beta increased both basal and tumor necrosis factor alpha-stimulated activities of MEKK1 in GSK3 beta(-/-) cells. Together, these observations suggest that GSK3 beta functions as a natural activator of MEKK1.
authors.affiliation: National Creative Research Initiative Center for Cell Death, Graduate School of Life Science and Biotechnology, Korea University, Seoul 136-701, Korea.
authors.forename: Jin Woo
authors.initials: JW
authors.lastname: Kim
authors.forename: Ji Eun
authors.initials: JE
authors.lastname: Lee
authors.forename: Myung Jin
authors.initials: MJ
authors.lastname: Kim
authors.forename: Eun-Gyung
authors.initials: EG
authors.lastname: Cho
authors.forename: Ssang-Goo
authors.initials: SG
authors.lastname: Cho
authors.forename: Eui-Ju
authors.initials: EJ
authors.lastname: Choi
mesh_terms: D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis; D060466:Axin Protein; D002460:Cell Line; D002478:Cells, Cultured; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism / Q000502:physiology*; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D018021:Lithium Chloride / Q000494:pharmacology; D048728:MAP Kinase Kinase Kinase 1; D051379:Mice; D018345:Mice, Knockout; D048055:Mitogen-Activated Protein Kinase 8; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011233:Precipitin Tests; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D012097:Repressor Proteins; D015398:Signal Transduction; D013997:Time Factors; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D014466:Ultraviolet Rays; D000077191:Wortmannin
chemical_list: D000730:Androstadienes; D060466:Axin Protein; D004791:Enzyme Inhibitors; D005982:Glutathione Transferase; D038362:Glycogen Synthase Kinase 3; D000071679:Glycogen Synthase Kinase 3 beta; D018021:Lithium Chloride; D048728:MAP Kinase Kinase Kinase 1; D048055:Mitogen-Activated Protein Kinase 8; D020928:Mitogen-Activated Protein Kinases; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases; D011506:Proteins; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D012097:Repressor Proteins; D014409:Tumor Necrosis Factor-alpha; D000077191:Wortmannin; C555451:AXIN1 protein, human; C000605506:GSK3B protein, human; C000605507:Gsk3b protein, mouse; C482576:MAP3K1 protein, human; C482578:Map3k1 protein, mouse