title: Antagonism to and intracellular sequestration of human tetherin by the human immunodeficiency virus type 2 envelope glycoprotein.
abstract: Tetherin (CD317/BST-2), an interferon-induced membrane protein, restricts the release of nascent retroviral particles from infected cell surfaces. While human immunodeficiency virus type 1 (HIV-1) encodes the accessory gene vpu to overcome the action of tetherin, the lineage of primate lentiviruses that gave rise to HIV-2 does not. It has been previously reported that the HIV-2 envelope glycoprotein has a Vpu-like function in promoting virus release. Here we demonstrate that the HIV-2 Rod envelope glycoprotein (HIV-2 Rod Env) is a tetherin antagonist. Expression of HIV-2 Rod Env, but not that of HIV-1 or the closely related simian immunodeficiency virus (SIV) SIVmac1A11, counteracts tetherin-mediated restriction of Vpu-defective HIV-1 in a cell-type-specific manner. This correlates with the ability of the HIV-2 Rod Env to mediate cell surface downregulation of tetherin. Antagonism requires an endocytic motif conserved across HIV/SIV lineages in the gp41 cytoplasmic tail, but specificity for tetherin is governed by extracellular determinants in the mature Env protein. Coimmunoprecipitation studies suggest an interaction between HIV-2 Rod Env and tetherin, but unlike studies with Vpu, we found no evidence of tetherin degradation. In the presence of HIV-2 Rod Env, tetherin localization is restricted to the trans-Golgi network, suggesting Env-mediated effects on tetherin trafficking sequester it from virus assembly sites on the plasma membrane. Finally, we recapitulated these observations in HIV-2-infected CD4+ T-cell lines, demonstrating that tetherin antagonism and sequestration occur at physiological levels of Env expression during virus replication.
authors.affiliation: Department of Infectious Disease, King's College London School of Medicine, Guy's Hospital, London SE1 9RT, United Kingdom.
authors.forename: Anna
authors.initials: A
authors.lastname: Le Tortorec
authors.forename: Stuart J D
authors.initials: SJ
authors.lastname: Neil
mesh_terms: D015703:Antigens, CD / Q000502:physiology*; D015496:CD4-Positive T-Lymphocytes / Q000502:physiology; D002460:Cell Line; D015536:Down-Regulation; D058851:GPI-Linked Proteins; D006056:Golgi Apparatus / Q000502:physiology; D015658:HIV Infections / Q000821:virology; D015497:HIV-1 / Q000502:physiology; D015498:HIV-2 / Q000502:physiology*; D006367:HeLa Cells; D006801:Humans; D019169:Jurkat Cells; D008562:Membrane Glycoproteins / Q000502:physiology*; D054299:env Gene Products, Human Immunodeficiency Virus / Q000502:physiology*; D000074010:Bone Marrow Stromal Antigen 2
chemical_list: D015703:Antigens, CD; D058851:GPI-Linked Proteins; D008562:Membrane Glycoproteins; D054299:env Gene Products, Human Immunodeficiency Virus; C094572:BST2 protein, human; D000074010:Bone Marrow Stromal Antigen 2