Vpu Antagonizes BST-2–Mediated Restriction of HIV-1 Release via β-TrCP and Endo-Lysosomal Trafficking

PLoS Pathogens

John C. Guatelli¹  Edward B. Stephens²  Autumn Ruiz²  Mark A. Skasko³  Chris Katsura³  Katie Fitzpatrick³  David Lau³  Richard S. Mitchell³  Richard Benarous⁴  Florence Margottin-Goguet⁵ 

[1] CellVir, Genopole, Evry, France;Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, Kansas, United States of America;Department of Medicine, University of California San Diego, La Jolla, California, United States of America;Inserm, U567, Paris, France;Institut Cochin, Université Paris Descartes, CNRS (UMR 8104), Paris, France

关键词: Cell membranes;    Membrane proteins;    Flow cytometry;    Cell staining;    Transfection;    Ubiquitin ligases;    Membrane trafficking;    Virions;   

DOI  :  10.1371/journal.ppat.1000450

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

The interferon-induced transmembrane protein BST-2/CD317 (tetherin) restricts the release of diverse enveloped viruses from infected cells. The HIV-1 accessory protein Vpu antagonizes this restriction by an unknown mechanism that likely involves the down-regulation of BST-2 from the cell surface. Here, we show that the optimal removal of BST-2 from the plasma membrane by Vpu requires the cellular protein β-TrCP, a substrate adaptor for a multi-subunit SCF E3 ubiquitin ligase complex and a known Vpu-interacting protein. β-TrCP is also required for the optimal enhancement of virion-release by Vpu. Mutations in the DSGxxS β-TrCP binding-motif of Vpu impair both the down-regulation of BST-2 and the enhancement of virion-release. Such mutations also confer dominant-negative activity, consistent with a model in which Vpu links BST-2 to β-TrCP. Optimal down-regulation of BST-2 from the cell surface by Vpu also requires the endocytic clathrin adaptor AP-2, although the rate of endocytosis is not increased; these data suggest that Vpu induces post-endocytic membrane trafficking events whose net effect is the removal of BST-2 from the cell surface. In addition to its marked effect on cell-surface levels, Vpu modestly decreases the total cellular levels of BST-2. The decreases in cell-surface and intracellular BST-2 are inhibited by bafilomycin A1, an inhibitor of endosomal acidification; these data suggest that Vpu induces late endosomal targeting and partial degradation of BST-2 in lysosomes. The Vpu-mediated decrease in surface expression is associated with reduced co-localization of BST-2 and the virion protein Gag along the plasma membrane. Together, the data support a model in which Vpu co-opts the β-TrCP/SCF E3 ubiquitin ligase complex to induce endosomal trafficking events that remove BST-2 from its site of action as a virion-tethering factor.

【 授权许可】

CC BY