title: The NS5A-binding heat shock proteins HSC70 and HSP70 play distinct roles in the hepatitis C viral life cycle.
abstract: We previously identified HSP70 and HSC70 in complex with NS5A in a proteomic screen. Here, coimmunoprecipitation studies confirmed NS5A/HSC70 complex formation during infection, and immunofluorescence studies showed NS5A and HSC70 to colocalize. Unlike HSP70, HSC70 knockdown did not decrease viral protein levels. Rather, intracellular infectious virion assembly was significantly impaired by HSC70 knockdown. We also discovered that both HSC70 nucleotide binding and substrate binding domains directly bind NS5A whereas only the HSP70 nucleotide binding domain does. Knockdown of both HSC70 and HSP70 demonstrated an additive reduction in virus production. This data suggests that HSC70 and HSP70 play discrete roles in the viral life cycle. Investigation of these different functions may facilitate developing of novel strategies that target host proteins to treat HCV infection.
authors.affiliation: Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America. Electronic address: RnKhch@ucla.edu.
authors.forename: Ronik
authors.initials: R
authors.lastname: Khachatoorian
authors.affiliation: Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America. Electronic address: GEkambaram@ucla.edu.
authors.forename: Ekambaram
authors.initials: E
authors.lastname: Ganapathy
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, United States of America. Electronic address: YasAhmadieh@ucla.edu.
authors.forename: Yasaman
authors.initials: Y
authors.lastname: Ahmadieh
authors.affiliation: Molecular Biology Interdepartmental Ph.D. Program (MBIDP), Molecular Biology Institute, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America; Molecular Biology Institute, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America. Electronic address: Wheatley.NM@gmail.com.
authors.forename: Nicole
authors.initials: N
authors.lastname: Wheatley
authors.affiliation: Department of Human Genetics, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America. Electronic address: Christopher.Sundberg@gmail.com.
authors.forename: Christopher
authors.initials: C
authors.lastname: Sundberg
authors.affiliation: Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America. Electronic address: CLJung@mednet.ucla.edu.
authors.forename: Chun-Ling
authors.initials: CL
authors.lastname: Jung
authors.affiliation: Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America; Department of Surgery, Regenerative Medicine Institute at Cedars-Sinai Medical Center, Los Angeles, CA, United States of America. Electronic address: Vaithi.Arumugaswami@cshs.org.
authors.forename: Vaithilingaraja
authors.initials: V
authors.lastname: Arumugaswami
authors.affiliation: Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America. Electronic address: SRaychau@ucla.edu.
authors.forename: Santanu
authors.initials: S
authors.lastname: Raychaudhuri
authors.affiliation: Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America; Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America; UCLA AIDS Institute, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America. Electronic address: Dasgupta@ucla.edu.
authors.forename: Asim
authors.initials: A
authors.lastname: Dasgupta
authors.affiliation: Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America; Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America; UCLA AIDS Institute, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America. Electronic address: SFrench@mednet.ucla.edu.
authors.forename: Samuel W
authors.initials: SW
authors.lastname: French
mesh_terms: D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D016174:Hepacivirus / Q000502:physiology*; D054884:Host-Pathogen Interactions; D006801:Humans; D047468:Immunoprecipitation; D018613:Microscopy, Confocal; D011485:Protein Binding; D017361:Viral Nonstructural Proteins / Q000378:metabolism*; D019065:Virus Assembly; D014779:Virus Replication; D012324:RNA-Dependent RNA Polymerase
chemical_list: D018840:HSP70 Heat-Shock Proteins; D017361:Viral Nonstructural Proteins; C087036:NS-5 protein, hepatitis C virus; D012324:RNA-Dependent RNA Polymerase
keywords: Assembly; HCV; HSC70; HSP70; IRES; NS5A
references.citation: J Virol. 1993 Jun;67(6):3338-44
references.pmid: 8388503
references.citation: J Gen Virol. 2009 Jun;90(Pt 6):1329-1334
references.pmid: 19264615
references.citation: Virology. 2012 Nov 25;433(2):346-55
references.pmid: 22975673
references.citation: Hepatology. 2012 Jun;55(6):1662-72
references.pmid: 22183951
references.citation: J Gen Virol. 1998 Sep;79 ( Pt 9):2239-47
references.pmid: 9747734
references.citation: J Virol. 2002 Dec;76(24):13001-14
references.pmid: 12438626
references.citation: FEBS Lett. 2007 Jul 31;581(19):3702-10
references.pmid: 17544402
references.citation: Hepatology. 2009 Dec;50(6):1756-64
references.pmid: 19839005
references.citation: Lancet Infect Dis. 2005 Sep;5(9):558-67
references.pmid: 16122679
references.citation: J Gen Virol. 2003 Mar;84(Pt 3):535-543
references.pmid: 12604803
references.citation: PLoS Pathog. 2008 Oct;4(10):e1000182
references.pmid: 18927624
references.citation: Protein Sci. 2013 May;22(5):660-5
references.pmid: 23456886
references.citation: Cell Mol Life Sci. 2005 Mar;62(6):670-84
references.pmid: 15770419
references.citation: J Virol. 2008 Feb;82(3):1073-83
references.pmid: 18032500
references.citation: J Biol Chem. 2010 Sep 3;285(36):28183-90
references.pmid: 20601427
references.citation: Hepatology. 2009 Jun;49(6):1798-809
references.pmid: 19434724
references.citation: Nat Rev Gastroenterol Hepatol. 2011 Feb;8(2):69-71
references.pmid: 21293503
references.citation: J Gen Virol. 2010 Jul;91(Pt 7):1728-36
references.pmid: 20219895
references.citation: J Biomed Biotechnol. 2010;2010:458927
references.pmid: 20150968
references.citation: J Clin Gastroenterol. 2002 Nov-Dec;35(5 Suppl 2):S72-8
references.pmid: 12394209
references.citation: Virology. 2006 Aug 1;351(2):349-59
references.pmid: 16713611
references.citation: Nat Rev Microbiol. 2007 Jun;5(6):453-63
references.pmid: 17487147
references.citation: J Virol. 2008 Feb;82(4):2004-12
references.pmid: 18057252
references.citation: J Hepatol. 2011 Nov;55(5):963-71
references.pmid: 21354229