title: Severe acute respiratory syndrome coronavirus papain-like protease suppressed alpha interferon-induced responses through downregulation of extracellular signal-regulated kinase 1-mediated signalling pathways.
abstract: Severe acute respiratory syndrome coronavirus (SARS-CoV) papain-like protease (PLpro), a deubiquitinating enzyme, reportedly blocks poly I : C-induced activation of interferon regulatory factor 3 and nuclear factor kappa B, reducing interferon (IFN) induction. This study investigated type I IFN antagonist mechanism of PLpro in human promonocytes. PLpro antagonized IFN-α-induced responses such as interferon-stimulated response element- and AP-1-driven promoter activation, protein kinase R, 2'-5'-oligoadenylate synthetase (OAS), interleukin (IL)-6 and IL-8 expression, and signal transducers and activators of transcription (STAT) 1 (Tyr701), STAT1 (Ser727) and c-Jun phosphorylation. A proteomics approach demonstrated downregulation of extracellular signal-regulated kinase (ERK) 1 and upregulation of ubiquitin-conjugating enzyme (UBC) E2-25k as inhibitory mechanism of PLpro on IFN-α-induced responses. IFN-α treatment significantly induced mRNA expression of UBC E2-25k, but not ERK1, causing time-dependent decrease of ERK1, but not ERK2, in PLpro-expressing cells. Poly-ubiquitination of ERK1 showed a relationship between ERK1 and ubiquitin proteasome signalling pathways associated with IFN antagonism by PLpro. Combination treatment of IFN-α and the proteasome inhibitor MG-132 showed a time-dependent restoration of ERK1 protein levels and significant increase of ERK1, STAT1 and c-Jun phosphorylation in PLpro-expressing cells. Importantly, PD098059 (an ERK1/2 inhibitor) treatment significantly reduced IFN-α-induced ERK1 and STAT1 phosphorylation, inhibiting IFN-α-induced expression of 2'-5'-OAS in vector control cells and PLpro-expressing cells. Overall results proved downregulation of ERK1 by ubiquitin proteasomes and suppression of interaction between ERK1 and STAT1 as type I IFN antagonist function of SARS-CoV PLpro.
authors.affiliation: Institute of Molecular Biology, National Chung Hsing University, Taichung, Taiwan, ROC.|Department of Medical Laboratory Science and Biotechnology, China Medical University, Taichung, Taiwan, ROC.
authors.forename: Shih-Wein
authors.initials: SW
authors.lastname: Li
authors.affiliation: Department of Medical Genetics and Medical Research, China Medical University Hospital, Taichung, Taiwan, ROC.|Institute of Molecular Biology, National Chung Hsing University, Taichung, Taiwan, ROC.
authors.forename: Chien-Chen
authors.initials: CC
authors.lastname: Lai
authors.affiliation: Department of Medical Laboratory Science and Biotechnology, China Medical University, Taichung, Taiwan, ROC.
authors.forename: Jia-Fong
authors.initials: JF
authors.lastname: Ping
authors.affiliation: Department of Medical Genetics and Medical Research, China Medical University Hospital, Taichung, Taiwan, ROC.
authors.forename: Fuu-Jen
authors.initials: FJ
authors.lastname: Tsai
authors.affiliation: Department of Medical Genetics and Medical Research, China Medical University Hospital, Taichung, Taiwan, ROC.
authors.forename: Lei
authors.initials: L
authors.lastname: Wan
authors.affiliation: Department of Medical Genetics and Medical Research, China Medical University Hospital, Taichung, Taiwan, ROC.
authors.forename: Ying-Ju
authors.initials: YJ
authors.lastname: Lin
authors.affiliation: Department of Biotechnology and Laboratory Science in Medicine, National Yang Ming University, Taipei, Taiwan, ROC.
authors.forename: Szu-Hao
authors.initials: SH
authors.lastname: Kung
authors.affiliation: Department of Biotechnology, Asia University, Wufeng, Taichung, Taiwan, ROC.|Clinical Virology Laboratory, Department of Laboratory Medicine, China Medical University Hospital, Taichung, Taiwan, ROC.|Department of Medical Laboratory Science and Biotechnology, China Medical University, Taichung, Taiwan, ROC.
authors.forename: Cheng-Wen
authors.initials: CW
authors.lastname: Lin
mesh_terms: D002460:Cell Line; D000086782:Coronavirus 3C Proteases; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D015536:Down-Regulation; D006801:Humans; D016898:Interferon-alpha / Q000037:antagonists & inhibitors* / Q000276:immunology; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors*; D009000:Monocytes / Q000821:virology; D020543:Proteome / Q000032:analysis; D045473:Severe acute respiratory syndrome-related coronavirus / Q000276:immunology* / Q000472:pathogenicity; D015398:Signal Transduction; D014764:Viral Proteins / Q000378:metabolism*
chemical_list: D016898:Interferon-alpha; D020543:Proteome; D014764:Viral Proteins; D048052:Mitogen-Activated Protein Kinase 3; D003546:Cysteine Endopeptidases; D000086782:Coronavirus 3C Proteases