title: Structure of human cytomegalovirus UL141 binding to TRAIL-R2 reveals novel, non-canonical death receptor interactions.
abstract: The TRAIL (TNF-related apoptosis inducing ligand) death receptors (DRs) of the tumor necrosis factor receptor superfamily (TNFRSF) can promote apoptosis and regulate antiviral immunity by maintaining immune homeostasis during infection. In turn, human cytomegalovirus (HCMV) expresses immunomodulatory proteins that down-regulate cell surface expression of TNFRSF members as well as poliovirus receptor-related proteins in an effort to inhibit host immune effector pathways that would lead to viral clearance. The UL141 glycoprotein of human cytomegalovirus inhibits host defenses by blocking cell surface expression of TRAIL DRs (by retention in ER) and poliovirus receptor CD155, a nectin-like Ig-fold molecule. Here we show that the immunomodulatory function of HCMV UL141 is associated with its ability to bind diverse proteins, while utilizing at least two distinct binding sites to selectively engage TRAIL DRs or CD155. Binding studies revealed high affinity interaction of UL141 with both TRAIL-R2 and CD155 and low affinity binding to TRAIL-R1. We determined the crystal structure of UL141 bound to TRAIL-R2 at 2.1 Å resolution, which revealed that UL141 forms a homodimer that engages two TRAIL-R2 monomers 90° apart to form a heterotetrameric complex. Our structural and biochemical data reveal that UL141 utilizes its Ig-domain to facilitate non-canonical death receptor interactions while UL141 partially mimics the binding site of TRAIL on TRAIL-R2, which we found to be distinct from that of CD155. Moreover, UL141 also binds to an additional surface patch on TRAIL-R2 that is distinct from the TRAIL binding site. Therefore, the breadth of UL141-mediated effects indicates that HCMV has evolved sophisticated strategies to evade the immune system by modulating multiple effector pathways.
authors.affiliation: Division of Cell Biology, La Jolla Institute for Allergy and Immunology, La Jolla, California, United States of America.
authors.forename: Ivana
authors.initials: I
authors.lastname: Nemčovičová
authors.forename: Chris A
authors.initials: CA
authors.lastname: Benedict
authors.forename: Dirk M
authors.initials: DM
authors.lastname: Zajonc
mesh_terms: D001665:Binding Sites; D003587:Cytomegalovirus / Q000737:chemistry / Q000378:metabolism*; D053418:Death Domain Receptor Signaling Adaptor Proteins / Q000737:chemistry / Q000378:metabolism*; D054884:Host-Pathogen Interactions; D006801:Humans; D057131:Immune Evasion / Q000235:genetics; D056747:Immunomodulation; D009154:Mutation; D011485:Protein Binding; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D053218:Receptors, Death Domain / Q000737:chemistry / Q000378:metabolism*; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D053418:Death Domain Receptor Signaling Adaptor Proteins; D053218:Receptors, Death Domain; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; C505639:TNFRSF10B protein, human
references.citation: J Mol Biol. 2005 May 20;348(5):1153-62
references.pmid: 15854651
references.citation: J Gen Virol. 2010 Aug;91(Pt 8):2034-2039
references.pmid: 20410314
references.citation: Proteins. 2003 Feb 15;50(3):437-50
references.pmid: 12557186
references.citation: Immunity. 1997 Dec;7(6):831-6
references.pmid: 9430228
references.citation: Acta Crystallogr D Biol Crystallogr. 2011 Jan;67(Pt 1):45-59
references.pmid: 21206061
references.citation: Nature. 2001 Aug 16;412(6848):701-5
references.pmid: 11507631
references.citation: Nat Immunol. 2005 Feb;6(2):181-8
references.pmid: 15640804
references.citation: Cell. 1993 May 7;73(3):431-45
references.pmid: 8387891
references.citation: J Virol. 1996 Jan;70(1):78-83
references.pmid: 8523595
references.citation: J Exp Med. 2001 Mar 19;193(6):661-70
references.pmid: 11257133
references.citation: Nucleic Acids Res. 2009 Jan;37(Database issue):D355-9
references.pmid: 18996896
references.citation: J Pediatr. 2007 Dec;151(6):564-70
references.pmid: 18035130
references.citation: Protein Eng. 1990 Aug;3(8):713-9
references.pmid: 2217144
references.citation: J Exp Med. 2003 Aug 18;198(4):557-67
references.pmid: 12913096
references.citation: J Mol Recognit. 1996 Mar-Apr;9(2):113-7
references.pmid: 8877801
references.citation: Nucleic Acids Res. 2010 Jul;38(Web Server issue):W545-9
references.pmid: 20457744
references.citation: J Immunol. 2004 Apr 1;172(7):3994-8
references.pmid: 15034010
references.citation: Cell Host Microbe. 2013 Mar 13;13(3):324-35
references.pmid: 23498957
references.citation: Curr Opin Immunol. 2003 Feb;15(1):59-65
references.pmid: 12495734
references.citation: Acta Crystallogr D Biol Crystallogr. 2006 Jan;62(Pt 1):72-82
references.pmid: 16369096
references.citation: Acta Crystallogr D Biol Crystallogr. 1997 May 1;53(Pt 3):240-55
references.pmid: 15299926
references.citation: Cell. 2002 Nov 1;111(3):343-56
references.pmid: 12419245
references.citation: J Gen Virol. 2004 May;85(Pt 5):1301-1312
references.pmid: 15105547
references.citation: Protein Eng. 1991 Oct;4(7):785-91
references.pmid: 1665907
references.citation: J Immunol. 1999 Mar 1;162(5):2639-47
references.pmid: 10072506
references.citation: Curr Opin Immunol. 2011 Oct;23(5):627-31
references.pmid: 21920726
references.citation: Eur J Immunol. 2001 Nov;31(11):3138-46
references.pmid: 11745330
references.citation: Acta Crystallogr D Biol Crystallogr. 2005 Apr;61(Pt 4):449-57
references.pmid: 15805600
references.citation: PLoS Pathog. 2010 Jan 15;6(1):e1000723
references.pmid: 20090832
references.citation: Proc Natl Acad Sci U S A. 2012 Apr 3;109(14):5399-404
references.pmid: 22421438
references.citation: Proc Natl Acad Sci U S A. 1999 Oct 26;96(22):12379-83
references.pmid: 10535930
references.citation: Nat Rev Immunol. 2003 Jan;3(1):36-50
references.pmid: 12511874
references.citation: Protein Eng. 1991 Apr;4(4):385-9
references.pmid: 1715560
references.citation: J Clin Invest. 2001 Oct;108(7):971-9
references.pmid: 11581298
references.citation: Nat Immunol. 2007 Nov;8(11):1179-87
references.pmid: 17952043
references.citation: Proc Natl Acad Sci U S A. 2005 Sep 13;102(37):13218-23
references.pmid: 16131544
references.citation: Acta Crystallogr D Biol Crystallogr. 2004 Dec;60(Pt 12 Pt 1):2126-32
references.pmid: 15572765
references.citation: Methods Enzymol. 2003;374:300-21
references.pmid: 14696379
references.citation: Acta Crystallogr D Biol Crystallogr. 2011 Apr;67(Pt 4):271-81
references.pmid: 21460445
references.citation: Mol Cell. 1999 Oct;4(4):563-71
references.pmid: 10549288
references.citation: BMC Immunol. 2003 Mar 14;4:4
references.pmid: 12694635
references.citation: J Immunol. 2009 Dec 1;183(11):7286-96
references.pmid: 19915044
references.citation: Curr Top Microbiol Immunol. 2008;319:41-61
references.pmid: 18080414
references.citation: J Intern Med. 2010 May;267(5):483-501
references.pmid: 20433576
references.citation: J Clin Microbiol. 2000 Feb;38(2):839-45
references.pmid: 10655394
references.citation: J Biol Chem. 2000 Oct 6;275(40):31171-7
references.pmid: 10893238
references.citation: Cell. 1994 Mar 25;76(6):959-62
references.pmid: 8137429
references.citation: Nat Struct Biol. 1999 Nov;6(11):1048-53
references.pmid: 10542098
references.citation: Cancer Res. 2006 Sep 1;66(17):8520-8
references.pmid: 16951164
references.citation: J Appl Crystallogr. 2007 Aug 1;40(Pt 4):658-674
references.pmid: 19461840
references.citation: Proc Natl Acad Sci U S A. 2006 Jun 6;103(23):8634-9
references.pmid: 16731632
references.citation: J Gen Virol. 1991 Jun;72 ( Pt 6):1223-7
references.pmid: 2045789
references.citation: Acta Crystallogr A. 2008 Jan;64(Pt 1):112-22
references.pmid: 18156677
references.citation: Nat Rev Immunol. 2008 Nov;8(11):861-73
references.pmid: 18949019
references.citation: J Biol Chem. 2005 Nov 25;280(47):39553-61
references.pmid: 16169851
references.citation: Prog Biophys Mol Biol. 1999;72(3):245-70
references.pmid: 10581970