title: Sigma-1 receptor regulates early steps of viral RNA replication at the onset of hepatitis C virus infection.
abstract: Hepatitis C virus (HCV) genome replication is thought to occur in a membranous cellular compartment derived from the endoplasmic reticulum (ER). The molecular mechanisms by which these membrane-associated replication complexes are formed during HCV infection are only starting to be unraveled, and both viral and cellular factors contribute to their formation. In this study, we describe the discovery of nonopioid sigma-1 receptor (S1R) as a cellular factor that mediates the early steps of viral RNA replication. S1R is a cholesterol-binding protein that resides in lipid-rich areas of the ER and in mitochondrion-associated ER membranes (MAMs). Several functions have been ascribed to this ER-resident chaperone, many of which are related to Ca(2+) signaling at the MAMs and lipid storage and trafficking. Downregulation of S1R expression by RNA interference (RNAi) in Huh-7 cells leads to a proportional decrease in susceptibility to HCV infection, as shown by reduced HCV RNA accumulation and intra- and extracellular infectivity in single-cycle infection experiments. Similar RNAi studies in persistently infected cells indicate that S1R expression is not rate limiting for persistent HCV RNA replication, as marked reduction in S1R in these cells does not lead to any decrease in HCV RNA or viral protein expression. However, subgenomic replicon transfection experiments indicate that S1R expression is rate limiting for HCV RNA replication without impairing primary translation. Overall, our data indicate that the initial steps of HCV infection are regulated by S1R, a key component of MAMs, suggesting that these structures could serve as platforms for initial RNA replication during HCV infection.
authors.affiliation: Departamento de Biología Molecular y Celular, Centro Nacional de Biotecnología-CSIC, Madrid, Spain.
authors.forename: Martina
authors.initials: M
authors.lastname: Friesland
authors.forename: Lidia
authors.initials: L
authors.lastname: Mingorance
authors.forename: Josan
authors.initials: J
authors.lastname: Chung
authors.forename: Francis V
authors.initials: FV
authors.lastname: Chisari
authors.forename: Pablo
authors.initials: P
authors.lastname: Gastaminza
mesh_terms: D002460:Cell Line; D004721:Endoplasmic Reticulum / Q000235:genetics / Q000378:metabolism; D015967:Gene Expression Regulation, Viral; D016174:Hepacivirus / Q000235:genetics* / Q000502:physiology; D006526:Hepatitis C / Q000235:genetics / Q000378:metabolism* / Q000821:virology*; D006801:Humans; D012367:RNA, Viral / Q000235:genetics* / Q000378:metabolism; D017480:Receptors, sigma / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication; D000097605:Sigma-1 Receptor
chemical_list: D012367:RNA, Viral; D017480:Receptors, sigma; D000097605:Sigma-1 Receptor
references.citation: J Virol. 2001 Feb;75(3):1252-64
references.pmid: 11152498
references.citation: Proc Natl Acad Sci U S A. 2004 Oct 12;101(41):14949-54
references.pmid: 15466698
references.citation: Synapse. 2012 Jan;66(1):42-51
references.pmid: 21905129
references.citation: Curr Neuropharmacol. 2005 Oct;3(4):267-80
references.pmid: 18369400
references.citation: Cell Host Microbe. 2011 Jan 20;9(1):32-45
references.pmid: 21238945
references.citation: J Virol. 2004 Apr;78(7):3436-46
references.pmid: 15016866
references.citation: PLoS Pathog. 2012;8(8):e1002860
references.pmid: 22916015
references.citation: Proc Natl Acad Sci U S A. 2011 Aug 30;108(35):14590-5
references.pmid: 21844353
references.citation: J Gen Virol. 1977 Jul;36(1):59-74
references.pmid: 886304
references.citation: Cancer Res. 1982 Sep;42(9):3858-63
references.pmid: 6286115
references.citation: Int J Biochem Cell Biol. 2013 Jan;45(1):156-66
references.pmid: 22710347
references.citation: Am J Gastroenterol. 1999 Aug;94(8):2198-205
references.pmid: 10445550
references.citation: Mol Cell Neurosci. 2013 Jul;55:26-36
references.pmid: 22922446
references.citation: EMBO J. 2010 Aug 18;29(16):2715-23
references.pmid: 20717141
references.citation: J Virol. 2003 Apr;77(7):4160-8
references.pmid: 12634374
references.citation: Proc Natl Acad Sci U S A. 2010 Jan 5;107(1):291-6
references.pmid: 19995961
references.citation: Cell Host Microbe. 2010 Jul 22;8(1):77-85
references.pmid: 20638644
references.citation: Bioorg Med Chem. 2000 Aug;8(8):2105-11
references.pmid: 11003156
references.citation: J Pharmacol Exp Ther. 2012 Dec;343(3):578-86
references.pmid: 22923735
references.citation: J Virol. 2010 Nov;84(21):10999-1009
references.pmid: 20686033
references.citation: CNS Drugs. 2004;18(5):269-84
references.pmid: 15089113
references.citation: J Pharmacol Exp Ther. 2003 Aug;306(2):726-33
references.pmid: 12730356
references.citation: Rev Med Virol. 2007 Sep-Oct;17(5):343-54
references.pmid: 17563922
references.citation: J Virol. 2003 Mar;77(5):3007-19
references.pmid: 12584326
references.citation: Annu Rev Pathol. 2006;1:23-61
references.pmid: 18039107
references.citation: J Pharmacol Exp Ther. 2003 Aug;306(2):718-25
references.pmid: 12730355
references.citation: J Virol. 2011 Jun;85(11):5513-23
references.pmid: 21430055
references.citation: J Virol. 1998 Nov;72(11):8463-71
references.pmid: 9765382
references.citation: J Virol. 2008 Mar;82(5):2120-9
references.pmid: 18077707
references.citation: N Engl J Med. 2011 Jun 23;364(25):2405-16
references.pmid: 21696307
references.citation: PLoS Pathog. 2012;8(3):e1002561
references.pmid: 22396648
references.citation: PLoS Pathog. 2010 Jan;6(1):e1000719
references.pmid: 20062526
references.citation: J Virol. 2011 Jul;85(14):6963-76
references.pmid: 21543474
references.citation: Science. 1998 Jun 12;280(5370):1763-6
references.pmid: 9624056
references.citation: Cell. 2004 Oct 29;119(3):369-80
references.pmid: 15507208
references.citation: Biochim Biophys Acta. 2009 May;1787(5):539-46
references.pmid: 19094961
references.citation: Cell. 2010 May 28;141(5):799-811
references.pmid: 20510927
references.citation: Biophys J. 2004 Jun;86(6):3993-4003
references.pmid: 15189895
references.citation: J Virol. 2006 Nov;80(22):11082-93
references.pmid: 16956932
references.citation: N Engl J Med. 2011 Mar 31;364(13):1195-206
references.pmid: 21449783
references.citation: Gut. 2012 May;61 Suppl 1:i25-35
references.pmid: 22504917
references.citation: Proc Natl Acad Sci U S A. 2006 May 9;103(19):7408-13
references.pmid: 16651538
references.citation: Subcell Biochem. 2010;51:381-98
references.pmid: 20213551
references.citation: Nat Cell Biol. 2007 Sep;9(9):1089-97
references.pmid: 17721513
references.citation: J Cell Sci. 1996 Apr;109 ( Pt 4):787-92
references.pmid: 8718670
references.citation: J Virol. 2011 Sep;85(17):8870-83
references.pmid: 21697487
references.citation: Nat Rev Microbiol. 2007 Jun;5(6):453-63
references.pmid: 17487147
references.citation: J Gen Virol. 2003 Oct;84(Pt 10):2761-2769
references.pmid: 13679611
references.citation: RNA Biol. 2011 Mar-Apr;8(2):258-69
references.pmid: 21593584
references.citation: Proc Natl Acad Sci U S A. 2009 Aug 18;106(33):14046-51
references.pmid: 19666601
references.citation: Virology. 2004 Jul 1;324(2):450-61
references.pmid: 15207630
references.citation: J Biol Chem. 2011 Jan 28;286(4):3018-32
references.pmid: 21056986
references.citation: Cell Microbiol. 2008 Apr;10(4):821-7
references.pmid: 18081727
references.citation: J Exp Med. 2003 Mar 3;197(5):633-42
references.pmid: 12615904
references.citation: Curr Opin Virol. 2011 Jul;1(1):19-26
references.pmid: 22440563
references.citation: Nat Med. 2005 Jul;11(7):791-6
references.pmid: 15951748
references.citation: Cell Host Microbe. 2009 Dec 17;6(6):513-22
references.pmid: 20006840
references.citation: Cell. 2007 Nov 2;131(3):596-610
references.pmid: 17981125
references.citation: J Microsc. 2006 Dec;224(Pt 3):213-32
references.pmid: 17210054
references.citation: Hepatology. 2007 Jul;46(1):58-65
references.pmid: 17567832
references.citation: Proc Natl Acad Sci U S A. 2005 Jun 28;102(26):9294-9
references.pmid: 15939869
references.citation: J Virol. 2005 Mar;79(5):2689-99
references.pmid: 15708988
references.citation: Curr Opin Virol. 2012 Feb;2(1):14-9
references.pmid: 22440961
references.citation: Nat Methods. 2012 Jul;9(7):671-5
references.pmid: 22930834
references.citation: Br J Pharmacol. 2013 Mar;168(6):1445-55
references.pmid: 23121507
references.citation: Cent Nerv Syst Agents Med Chem. 2009 Sep;9(3):172-83
references.pmid: 20021351
references.citation: J Biol Chem. 2003 Dec 12;278(50):50301-8
references.pmid: 12963739
references.citation: Curr Opin Virol. 2012 Dec;2(6):725-32
references.pmid: 23083892
references.citation: J Virol. 2008 Jul;82(14):7034-46
references.pmid: 18480457
references.citation: Mol Pharmacol. 2010 Apr;77(4):517-28
references.pmid: 20053954
references.citation: Antiviral Res. 2003 Oct;60(2):103-9
references.pmid: 14638405
references.citation: PLoS Pathog. 2012;8(12):e1003056
references.pmid: 23236278
references.citation: Anal Biochem. 1987 Apr;162(1):156-9
references.pmid: 2440339