title: SARS-coronavirus protein 6 conformations required to impede protein import into the nucleus.
abstract: The severe acute respiratory syndrome coronavirus (SARS-CoV) genome encodes eight accessory proteins. Accessory protein 6 is a 63-residue amphipathic peptide that accelerates coronavirus infection kinetics in cell culture and in mice. Protein 6 is minimally bifunctional, with an N-terminal lipophilic part implicated in accelerating viral growth and a C-terminal hydrophilic part interfering with general protein import into the nucleus. This interference with nuclear import requires interaction between protein 6 and cellular karyopherins, a process that typically involves nuclear localization signal (NLS) motifs. Here we dissected protein 6 using site-directed mutagenesis and found no evidence for a classical NLS. Furthermore, we found that the C-terminal tail of protein 6 impeded nuclear import only in the context of a lipophilic N-terminus, which could be derived from membrane proteins unrelated to protein 6. These findings are discussed in the context of the proposed protein 6 structure.
authors.affiliation: Department of Microbiology and Immunology, Loyola University Medical Center, 2160 South First Avenue, Maywood, IL 60153, USA.
authors.forename: Snawar
authors.initials: S
authors.lastname: Hussain
authors.forename: Tom
authors.initials: T
authors.lastname: Gallagher
mesh_terms: D021581:Active Transport, Cell Nucleus; D000818:Animals; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D006801:Humans; D028884:Karyopherins / Q000378:metabolism; D051379:Mice; D016297:Mutagenesis, Site-Directed; D050505:Mutant Proteins / Q000235:genetics* / Q000378:metabolism*; D019913:Nuclear Localization Signals; D045473:Severe acute respiratory syndrome-related coronavirus / Q000502:physiology*; D014764:Viral Proteins / Q000235:genetics* / Q000378:metabolism*
chemical_list: D028884:Karyopherins; D050505:Mutant Proteins; D019913:Nuclear Localization Signals; D014764:Viral Proteins; C507223:protein 6, SARS virus
references.citation: J Virol. 2007 Oct;81(20):11054-68
references.pmid: 17686858
references.citation: Mol Cells. 2006 Apr 30;21(2):186-91
references.pmid: 16682811
references.citation: J Virol. 2009 Mar;83(5):2368-73
references.pmid: 19091867
references.citation: Proc Natl Acad Sci U S A. 2006 Aug 15;103(33):12540-5
references.pmid: 16894145
references.citation: Proc Natl Acad Sci U S A. 1995 Jul 3;92(14):6532-6
references.pmid: 7604027
references.citation: J Virol. 2005 May;79(9):5288-95
references.pmid: 15827143
references.citation: J Biol Chem. 2005 Apr 22;280(16):16038-44
references.pmid: 15705574
references.citation: Nature. 1984 Sep 6-11;311(5981):33-8
references.pmid: 6088992
references.citation: Science. 2005 Oct 28;310(5748):676-9
references.pmid: 16195424
references.citation: J Virol. 2005 Dec;79(23):14909-22
references.pmid: 16282490
references.citation: Nat Rev Microbiol. 2003 Dec;1(3):209-18
references.pmid: 15035025
references.citation: J Mol Biol. 2003 Aug 29;331(5):991-1004
references.pmid: 12927536
references.citation: EMBO J. 1997 Dec 1;16(23):7067-77
references.pmid: 9384585
references.citation: Structure. 2005 Jan;13(1):75-85
references.pmid: 15642263
references.citation: J Virol. 2007 Jan;81(2):718-31
references.pmid: 17079322
references.citation: J Infect Dis. 2007 Aug 1;196(3):405-15
references.pmid: 17597455
references.citation: Cell Death Differ. 2007 Mar;14(3):395-9
references.pmid: 17186024
references.citation: FEBS Lett. 2005 Dec 19;579(30):6763-8
references.pmid: 16310783
references.citation: J Virol. 2007 Oct;81(20):11520-5
references.pmid: 17670827
references.citation: J Virol. 2004 Dec;78(24):14043-7
references.pmid: 15564512
references.citation: J Virol. 2005 Sep;79(17):11335-42
references.pmid: 16103185
references.citation: Curr Biol. 1995 Apr 1;5(4):383-92
references.pmid: 7627554
references.citation: J Virol. 2008 Jul;82(14):7212-22
references.pmid: 18448520
references.citation: J Virol. 2007 Jan;81(2):548-57
references.pmid: 17108024
references.citation: Science. 2003 May 30;300(5624):1394-9
references.pmid: 12730500
references.citation: Zhonghua Liu Xing Bing Xue Za Zhi. 2005 Feb;26(2):84-7
references.pmid: 15921605
references.citation: J Virol. 2003 Mar;77(6):3734-48
references.pmid: 12610148
references.citation: J Virol. 2007 Feb;81(3):1220-9
references.pmid: 17108045
references.citation: J Virol. 2000 May;74(9):4319-26
references.pmid: 10756047
references.citation: J Biol Chem. 2002 Mar 8;277(10):8130-9
references.pmid: 11744739
references.citation: Virology. 2006 Oct 10;354(1):132-42
references.pmid: 16876844
references.citation: J Virol. 2010 Apr;84(7):3542-51
references.pmid: 20106914
references.citation: J Virol. 2007 Sep;81(18):9812-24
references.pmid: 17596301
references.citation: Virol J. 2005 Aug 17;2:66
references.pmid: 16107218