Antagonism of tetherin restriction of HIV-1 release by Vpu involves binding and sequestration of the restriction factor in a perinuclear compartment

PLoS Pathog. 2010 Apr 8;6(4):e1000856. doi: 10.1371/journal.ppat.1000856.


The Vpu accessory protein promotes HIV-1 release by counteracting Tetherin/BST-2, an interferon-regulated restriction factor, which retains virions at the cell-surface. Recent reports proposed beta-TrCP-dependent proteasomal and/or endo-lysosomal degradation of Tetherin as potential mechanisms by which Vpu could down-regulate Tetherin cell-surface expression and antagonize this restriction. In all of these studies, Tetherin degradation did not, however, entirely account for Vpu anti-Tetherin activity. Here, we show that Vpu can promote HIV-1 release without detectably affecting Tetherin steady-state levels or turnover, suggesting that Tetherin degradation may not be necessary and/or sufficient for Vpu anti-Tetherin activity. Even though Vpu did not enhance Tetherin internalization from the plasma membrane (PM), it did significantly slow-down the overall transport of the protein towards the cell-surface. Accordingly, Vpu expression caused a specific removal of cell-surface Tetherin and a re-localization of the residual pool of Tetherin in a perinuclear compartment that co-stained with the TGN marker TGN46 and Vpu itself. This re-localization of Tetherin was also observed with a Vpu mutant unable to recruit beta-TrCP, suggesting that this activity is taking place independently from beta-TrCP-mediated trafficking and/or degradation processes. We also show that Vpu co-immunoprecipitates with Tetherin and that this interaction involves the transmembrane domains of the two proteins. Importantly, this association was found to be critical for reducing cell-surface Tetherin expression, re-localizing the restriction factor in the TGN and promoting HIV-1 release. Overall, our results suggest that association of Vpu to Tetherin affects the outward trafficking and/or recycling of the restriction factor from the TGN and as a result promotes its sequestration away from the PM where productive HIV-1 assembly takes place. This mechanism of antagonism that results in TGN trapping is likely to be augmented by beta-TrCP-dependent degradation, underlining the need for complementary and perhaps synergistic strategies to effectively counteract the powerful restrictive effects of human Tetherin.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens, CD / metabolism*
  • Blotting, Western
  • Cell Line
  • Endocytosis / physiology
  • Flow Cytometry
  • GPI-Linked Proteins
  • HIV-1 / metabolism*
  • HeLa Cells
  • Human Immunodeficiency Virus Proteins / metabolism*
  • Humans
  • Immunoprecipitation
  • Membrane Glycoproteins / metabolism*
  • Microscopy, Confocal
  • Protein Transport / physiology
  • Viral Regulatory and Accessory Proteins / metabolism*
  • Virus Release / physiology*


  • Antigens, CD
  • BST2 protein, human
  • GPI-Linked Proteins
  • Human Immunodeficiency Virus Proteins
  • Membrane Glycoproteins
  • Viral Regulatory and Accessory Proteins
  • vpu protein, Human immunodeficiency virus 1