title: ERK and p38 MAP kinase are involved in downregulation of cell surface TNF receptor 1 induced by acetoxycycloheximide.
abstract: Tumor necrosis factor (TNF)-alpha activates the nuclear factor kappaB (NF-kappaB) signaling pathway. The protein synthesis inhibitor cycloheximide (CHX) and its structural derivative acetoxycycloheximide (Ac-CHX) have been recently shown to block the TNF-alpha-induced activation of NF-kappaB via ectodomain shedding of TNF receptor 1 (TNF-R1) in human lung carcinoma A549 cells. In this study, we show that ERK and p38 MAP kinase are involved in the downregulation of cell surface TNF-R1 upon exposure to Ac-CHX and the subsequent inhibition of TNF-alpha-induced NF-kappaB activation. Ac-CHX was capable of promoting the sustained activation of ERK, JNK, and p38 MAP kinase. Treatment with the MEK inhibitor U0126 and the p38 MAP kinase inhibitor SB203580, but not the JNK inhibitor SP600125, reversed the diminished expression of cell surface TNF-R1 as well as the blockade of TNF-alpha-induced IkappaBalpha degradation in Ac-CHX-treated cells. Our results indicate that Ac-CHX triggers the downregulation of cell surface TNF-R1 via the activation of ERK and p38 MAP kinase, thereby preventing activation of the NF-kappaB signaling pathway by TNF-alpha.
authors.affiliation: Center for Biological Resources and Informatics, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan.
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Ogura
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Tsukumo
authors.forename: Hikaru
authors.initials: H
authors.lastname: Sugimoto
authors.forename: Masayuki
authors.initials: M
authors.lastname: Igarashi
authors.forename: Kazuo
authors.initials: K
authors.lastname: Nagai
authors.forename: Takao
authors.initials: T
authors.lastname: Kataoka
mesh_terms: D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism*; D003513:Cycloheximide / Q000031:analogs & derivatives* / Q000494:pharmacology; D015536:Down-Regulation; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D006801:Humans; D016328:NF-kappa B / Q000378:metabolism*; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
chemical_list: D016328:NF-kappa B; D047888:Receptors, Tumor Necrosis Factor, Type I; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D003513:Cycloheximide; D048049:Extracellular Signal-Regulated MAP Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C004434:acetoxycycloheximide