title: Negative feedback regulation of ASK1 by protein phosphatase 5 (PP5) in response to oxidative stress.
abstract: Apoptosis signal-regulating kinase 1 (ASK1) is a MAP kinase kinase kinase (MAPKKK) that activates the JNK and p38 MAP kinase cascades and is activated in response to oxidative stress such as hydrogen peroxide (H(2)O(2)). A yeast two-hybrid screening identified a serine/threonine protein phosphatase 5 (PP5) as a binding partner of ASK1. PP5 directly dephosphorylated an essential phospho-threonine residue within the kinase domain of ASK1 and thereby inactivated ASK1 activity in vitro and in vivo. The interaction between PP5 and ASK1 was induced by H(2)O(2) treatment and was followed by the decrease in ASK1 activity. PP5 inhibited not only H(2)O(2)-induced sustained activation of ASK1 but also ASK1-dependent apoptosis. Thus, PP5 appears to act as a physiological inhibitor of ASK1-JNK/p38 pathways by negative feedback.
authors.affiliation: Cell Signaling, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Morita
authors.forename: M
authors.initials: M
authors.lastname: Saitoh
authors.forename: K
authors.initials: K
authors.lastname: Tobiume
authors.forename: H
authors.initials: H
authors.lastname: Matsuura
authors.forename: S
authors.initials: S
authors.lastname: Enomoto
authors.forename: H
authors.initials: H
authors.lastname: Nishitoh
authors.forename: H
authors.initials: H
authors.lastname: Ichijo
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D019556:COS Cells; D002460:Cell Line; D025461:Feedback, Physiological / Q000502:physiology*; D006367:HeLa Cells / Q000201:enzymology; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007668:Kidney / Q000166:cytology / Q000378:metabolism; D048848:MAP Kinase Kinase Kinase 5; D020930:MAP Kinase Kinase Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D016877:Oxidants / Q000494:pharmacology; D018384:Oxidative Stress / Q000502:physiology*; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D011485:Protein Binding / Q000187:drug effects / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D020798:Two-Hybrid System Techniques
chemical_list: D009687:Nuclear Proteins; D016877:Oxidants; D014409:Tumor Necrosis Factor-alpha; D006861:Hydrogen Peroxide; D048848:MAP Kinase Kinase Kinase 5; D020930:MAP Kinase Kinase Kinases; C482858:MAP3K5 protein, human; D010749:Phosphoprotein Phosphatases; C089641:protein phosphatase 5