title: The CD225 domain of IFITM3 is required for both IFITM protein association and inhibition of influenza A virus and dengue virus replication.
abstract: The interferon-induced transmembrane protein 3 (IFITM3) gene is an interferon-stimulated gene that inhibits the replication of multiple pathogenic viruses in vitro and in vivo. IFITM3 is a member of a large protein superfamily, whose members share a functionally undefined area of high amino acid conservation, the CD225 domain. We performed mutational analyses of IFITM3 and identified multiple residues within the CD225 domain, consisting of the first intramembrane domain (intramembrane domain 1 [IM1]) and a conserved intracellular loop (CIL), that are required for restriction of both influenza A virus (IAV) and dengue virus (DENV) infection in vitro. Two phenylalanines within IM1 (F75 and F78) also mediate a physical association between IFITM proteins, and the loss of this interaction decreases IFITM3-mediated restriction. By extension, similar IM1-mediated associations may contribute to the functions of additional members of the CD225 domain family. IFITM3's distal N-terminal domain is also needed for full antiviral activity, including a tyrosine (Y20), whose alteration results in mislocalization of a portion of IFITM3 to the cell periphery and surface. Comparative analyses demonstrate that similar molecular determinants are needed for IFITM3's restriction of both IAV and DENV. However, a portion of the CIL including Y99 and R87 is preferentially needed for inhibition of the orthomyxovirus. Several IFITM3 proteins engineered with rare single-nucleotide polymorphisms demonstrated reduced expression or mislocalization, and these events were associated with enhanced viral replication in vitro, suggesting that possessing such alleles may impact an individual's risk for viral infection. On the basis of this and other data, we propose a model for IFITM3-mediated restriction.
authors: Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
authors: Sinu P
authors: SP
authors: John
authors: Christopher R
authors: CR
authors: Chin
authors: Jill M
authors: JM
authors: Perreira
authors: Eric M
authors: EM
authors: Feeley
authors: Aaron M
authors: AM
authors: Aker
authors: George
authors: G
authors: Savidis
authors: Sarah E
authors: SE
authors: Smith
authors: Andrew E H
authors: AE
authors: Elia
authors: Aaron R
authors: AR
authors: Everitt
authors: Mehul
authors: M
authors: Vora
authors: Thomas
authors: T
authors: Pertel
authors: Stephen J
authors: SJ
authors: Elledge
authors: Paul
authors: P
authors: Kellam
authors: Abraham L
authors: AL
authors: Brass
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D018929:Cell Culture Techniques; D003001:Cloning, Molecular; D017124:Conserved Sequence / Q000235:genetics; D004252:DNA Mutational Analysis; D018076:DNA, Complementary / Q000235:genetics; D003716:Dengue Virus / Q000502:physiology*; D004285:Dogs; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D015151:Immunoblotting; D047468:Immunoprecipitation; D009980:Influenza A virus / Q000502:physiology*; D061985:Madin Darby Canine Kidney Cells; D013058:Mass Spectrometry; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism*; D018613:Microscopy, Confocal; D008954:Models, Biological; D008969:Molecular Sequence Data; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D017434:Protein Structure, Tertiary / Q000235:genetics; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D014779:Virus Replication / Q000235:genetics / Q000502:physiology*
chemical_list: D018076:DNA, Complementary; C080082:IFITM3 protein, human; D008565:Membrane Proteins; D016601:RNA-Binding Proteins
references: Mol Cell Proteomics. 2008 Sep;7(9):1763-77
references: 18515860
references: Elife. 2013 Feb 19;2:e00333
references: 23550179
references: J Virol. 2010 Aug;84(16):8332-41
references: 20534863
references: Science. 2008 Feb 15;319(5865):921-6
references: 18187620
references: J Biol Chem. 2012 Jun 1;287(23):19631-41
references: 22511783
references: Dev Cell. 2012 Apr 17;22(4):691-2
references: 22516194
references: Cell. 2012 Mar 30;149(1):124-36
references: 22464325
references: Mol Cell. 2009 Oct 23;36(2):326-39
references: 19854140
references: J Proteome Res. 2008 Aug;7(8):3304-13
references: 18578522
references: PLoS Pathog. 2011 Jan 06;7(1):e1001258
references: 21253575
references: J Cell Biol. 2007 Jan 29;176(3):249-54
references: 17242068
references: Nature. 2011 Apr 28;472(7344):481-5
references: 21478870
references: Nat Commun. 2013;4:1418
references: 23361009
references: J Biol Chem. 1990 Feb 25;265(6):3116-23
references: 1968060
references: Biochim Biophys Acta. 2006 Aug;1761(8):805-11
references: 16616874
references: Biol Chem. 2012 Nov;393(11):1231-45
references: 23109541
references: Nature. 2012 Mar 25;484(7395):519-23
references: 22446628
references: J Virol. 2011 Mar;85(5):2126-37
references: 21177806
references: Biochemistry. 2012 Dec 11;51(49):9782-95
references: 23163284
references: Nat Immunol. 2013 Mar;14(3):238-45
references: 23354485
references: J Virol. 2012 Dec;86(24):13697-707
references: 23055554
references: PLoS Pathog. 2011 Oct;7(10):e1002337
references: 22046135
references: PLoS One. 2011 Jan 06;6(1):e15640
references: 21253578
references: Nat Chem Biol. 2010 Aug;6(8):610-4
references: 20601941
references: Cell. 2009 Dec 24;139(7):1255-67
references: 20064372
references: Nat Struct Mol Biol. 2008 Jul;15(7):690-8
references: 18596815
references: Ann Biomed Eng. 2010 Jan;38(1):109-17
references: 19862617
references: Cell. 2009 Dec 24;139(7):1243-54
references: 20064371
references: J Virol. 2010 Dec;84(24):12646-57
references: 20943977
references: Nucleic Acids Res. 2012 Jan;40(Database issue):D290-301
references: 22127870