The ESCRT-0 component HRS is required for HIV-1 Vpu-mediated BST-2/tetherin down-regulation

PLoS Pathog. 2011 Feb 3;7(2):e1001265. doi: 10.1371/journal.ppat.1001265.

Abstract

The Endosomal Sorting Complexes Required for Transport (ESCRT) machinery, a highly conserved set of four hetero-oligomeric protein complexes, is required for multivesicular body formation, sorting ubiquitinylated membrane proteins for lysosomal degradation, cytokinesis and the final stages of assembly of a number of enveloped viruses, including the human immunodeficiency viruses. Here, we show an additional role for the ESCRT machinery in HIV-1 release. BST-2/tetherin is a restriction factor that impedes HIV release by tethering mature virus particles to the plasma membrane. We found that HRS, a key component of the ESCRT-0 complex, promotes efficient release of HIV-1 and that siRNA-mediated HRS depletion induces a BST-2/tetherin phenotype. This activity is related to the ability of the HIV-1 Vpu protein to down-regulate BST-2/tetherin. We found that BST-2/tetherin undergoes constitutive ESCRT-dependent sorting for lysosomal degradation and that this degradation is enhanced by Vpu expression. We demonstrate that Vpu-mediated BST-2/tetherin down-modulation and degradation require HRS (ESCRT-0) function and that knock down of HRS increases cellular levels of BST-2/tetherin and restricts virus release. Furthermore, HRS co-precipitates with Vpu and BST-2. Our results provide further insight into the mechanism by which Vpu counteracts BST-2/tetherin and promotes HIV-1 dissemination, and they highlight an additional role for the ESCRT machinery in virus release.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens, CD / genetics*
  • Antigens, CD / metabolism
  • Cells, Cultured
  • Down-Regulation
  • Endosomal Sorting Complexes Required for Transport / antagonists & inhibitors
  • Endosomal Sorting Complexes Required for Transport / genetics
  • Endosomal Sorting Complexes Required for Transport / metabolism
  • Endosomal Sorting Complexes Required for Transport / physiology*
  • GPI-Linked Proteins / genetics
  • GPI-Linked Proteins / metabolism
  • Gene Expression Regulation / drug effects
  • HIV-1 / metabolism
  • HIV-1 / physiology
  • HeLa Cells
  • Human Immunodeficiency Virus Proteins / metabolism
  • Human Immunodeficiency Virus Proteins / physiology*
  • Humans
  • Phosphoproteins / antagonists & inhibitors
  • Phosphoproteins / genetics
  • Phosphoproteins / metabolism
  • Phosphoproteins / physiology*
  • Protein Processing, Post-Translational / genetics
  • RNA, Small Interfering / genetics
  • RNA, Small Interfering / pharmacology
  • Transfection
  • Viral Load / drug effects
  • Viral Regulatory and Accessory Proteins / metabolism
  • Viral Regulatory and Accessory Proteins / physiology*
  • Virion / drug effects

Substances

  • Antigens, CD
  • BST2 protein, human
  • Endosomal Sorting Complexes Required for Transport
  • GPI-Linked Proteins
  • Human Immunodeficiency Virus Proteins
  • Phosphoproteins
  • RNA, Small Interfering
  • Viral Regulatory and Accessory Proteins
  • hepatocyte growth factor-regulated tyrosine kinase substrate
  • vpu protein, Human immunodeficiency virus 1