title: A Genetic Screen Identifies a Critical Role for the WDR81-WDR91 Complex in the Trafficking and Degradation of Tetherin.
abstract: Tetherin (BST2/CD317) is a viral restriction factor that anchors enveloped viruses to host cells and limits viral spread. The HIV-1 Vpu accessory protein counteracts tetherin by decreasing its cell surface expression and targeting it for ubiquitin-dependent endolysosomal degradation. Although the Vpu-mediated downregulation of tetherin has been extensively studied, the molecular details are not completely elucidated. We therefore used a forward genetic screen in human haploid KBM7 cells to identify novel genes required for tetherin trafficking. Our screen identified WDR81 as a novel gene required for tetherin trafficking and degradation in both the presence and absence of Vpu. WDR81 is a BEACH-domain containing protein that is also required for the degradation of EGF-stimulated epidermal growth factor receptor (EGFR) and functions in a complex with the WDR91 protein. In the absence of WDR81 the endolysosomal compartment appears swollen, with enlarged early and late endosomes and reduced delivery of endocytosed dextran to cathepsin-active lysosomes. Our data suggest a role for the WDR81-WDR91 complex in the fusion of endolysosomal compartments and the absence of WDR81 leads to impaired receptor trafficking and degradation.
authors.affiliation: Cambridge Institute for Medical Research, University of Cambridge School of Clinical Medicine, Wellcome Trust/MRC Building Biomedical Campus, Cambridge, CB2 0XY, UK.
authors.forename: Radu
authors.initials: R
authors.lastname: Rapiteanu
authors.affiliation: Departments of Medicine and Clinical Biochemistry, University of Cambridge School of Clinical Medicine, Wellcome Trust/MRC Building Biomedical Campus, Cambridge, CB2 0XY, UK.
authors.forename: Luther J
authors.initials: LJ
authors.lastname: Davis
authors.affiliation: Cambridge Institute for Medical Research, University of Cambridge School of Clinical Medicine, Wellcome Trust/MRC Building Biomedical Campus, Cambridge, CB2 0XY, UK.
authors.forename: James C
authors.initials: JC
authors.lastname: Williamson
authors.affiliation: Cambridge Institute for Medical Research, University of Cambridge School of Clinical Medicine, Wellcome Trust/MRC Building Biomedical Campus, Cambridge, CB2 0XY, UK.
authors.forename: Richard T
authors.initials: RT
authors.lastname: Timms
authors.affiliation: Departments of Medicine and Clinical Biochemistry, University of Cambridge School of Clinical Medicine, Wellcome Trust/MRC Building Biomedical Campus, Cambridge, CB2 0XY, UK.
authors.forename: J
authors.initials: J
authors.lastname: Paul Luzio
authors.affiliation: Cambridge Institute for Medical Research, University of Cambridge School of Clinical Medicine, Wellcome Trust/MRC Building Biomedical Campus, Cambridge, CB2 0XY, UK.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Lehner
mesh_terms: D015703:Antigens, CD / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism; D058851:GPI-Linked Proteins / Q000378:metabolism; D015497:HIV-1 / Q000378:metabolism; D006367:HeLa Cells; D054298:Human Immunodeficiency Virus Proteins / Q000235:genetics; D006801:Humans; D008247:Lysosomes / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D021381:Protein Transport; D054334:Viral Regulatory and Accessory Proteins / Q000235:genetics; D000074010:Bone Marrow Stromal Antigen 2; D000086082:Viroporin Proteins
chemical_list: D015703:Antigens, CD; D002352:Carrier Proteins; D058851:GPI-Linked Proteins; D054298:Human Immunodeficiency Virus Proteins; D009419:Nerve Tissue Proteins; D054334:Viral Regulatory and Accessory Proteins; C094572:BST2 protein, human; D000074010:Bone Marrow Stromal Antigen 2; C000609634:WDR81 protein, human; C000609633:WDR91 protein, human; C514859:vpu protein, Human immunodeficiency virus 1; D000086082:Viroporin Proteins
keywords: CAMRQ2; EGFR; HIV-Vpu; KBM7; WDR81; WDR91; early endosomes; endocytosis; human haploid cells; lysosomes; tetherin