title: GSK-3β-induced ASK1 stabilization is crucial in LPS-induced endotoxin shock.
abstract: Glycogen synthase kinase-3β (GSK-3β), a multifunctional kinase, is a regulator of lipopolysaccharide (LPS)-mediated septic shock. Apoptosis signal-regulating kinase 1 (ASK1) is also required for LPS-induced activation of p38, which is a crucial determinant for the production of pro-inflammatory cytokines via Toll-like receptor 4 (TLR4) in endotoxemia. Here, we show that attenuation of endotoxemia induced by GSK-3 inhibition is caused by the ASK1 reduction-mediated inhibition of p38, a representative downstream kinase of ASK1. LPS-stimulated activation of p38 was blocked by the reduction of ASK1 via the knockdown of GSK-3β. In addition, compared with L929 control cells, ASK1 protein was reduced in L929 cells stably expressing Wnt-3a and in which β-catenin was active, due to the inhibition of GSK-3β activity. GSK-3β inhibition-mediated ASK1 reduction was also confirmed by reduced ASK1 in GSK-3β-deficient mouse embryo fibroblasts (MEFs) and MCF7 GSK-3β siRNA cells. Furthermore, ASK1 protein stability was also attenuated in MCF7 GSK-3β siRNA cells compared with GFP control cells. Consistent with stability data, a much stronger ubiquitination of ASK1 was observed in cells in which GSK-3β was knocked down. These findings suggest that GSK-3β crosstalks with p38 kinase via the regulation of ASK1 protein stability in endotoxemia.
authors.affiliation: Laboratories of Cell Death and Human Diseases, School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, South Korea.
authors.forename: Kyung Tae
authors.initials: KT
authors.lastname: Noh
authors.forename: Yeong-Min
authors.initials: YM
authors.lastname: Park
authors.forename: Ssang-Goo
authors.initials: SG
authors.lastname: Cho
authors.forename: Eui-Ju
authors.initials: EJ
authors.lastname: Choi
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology; D002478:Cells, Cultured; D004622:Embryo, Mammalian / Q000166:cytology / Q000378:metabolism; D019446:Endotoxemia / Q000378:metabolism* / Q000473:pathology*; D005260:Female; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D038362:Glycogen Synthase Kinase 3 / Q000037:antagonists & inhibitors / Q000502:physiology*; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D015151:Immunoblotting; D008070:Lipopolysaccharides / Q000494:pharmacology*; D048848:MAP Kinase Kinase Kinase 5 / Q000737:chemistry* / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D034741:RNA, Small Interfering / Q000235:genetics; D051197:Toll-Like Receptor 4 / Q000378:metabolism; D054875:Ubiquitination; D051153:Wnt Proteins / Q000378:metabolism; D060508:Wnt3 Protein; D060509:Wnt3A Protein; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D008070:Lipopolysaccharides; D034741:RNA, Small Interfering; D051197:Toll-Like Receptor 4; C555510:WNT3A protein, human; D051153:Wnt Proteins; D060508:Wnt3 Protein; D060509:Wnt3A Protein; C555511:Wnt3a protein, mouse; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; C000605507:Gsk3b protein, mouse; D048051:p38 Mitogen-Activated Protein Kinases; D048848:MAP Kinase Kinase Kinase 5; D038362:Glycogen Synthase Kinase 3