Human ESCRT-II complex and its role in human immunodeficiency virus type 1 release

J Virol. 2006 Oct;80(19):9465-80. doi: 10.1128/JVI.01049-06.

Abstract

The budding of many enveloped RNA viruses, including human immunodeficiency virus type 1 (HIV-1), requires some of the same cellular machinery as vesicle formation at the multivesicular body (MVB). In Saccharomyces cerevisiae, the ESCRT-II complex performs a central role in MVB protein sorting and vesicle formation, as it is recruited by the upstream ESCRT-I complex and nucleates assembly of the downstream ESCRT-III complex. Here, we report that the three subunits of human ESCRT-II, EAP20, EAP30, and EAP45, have a number of properties in common with their yeast orthologs. Specifically, EAP45 bound ubiquitin via its N-terminal GRAM-like ubiquitin-binding in EAP45 (GLUE) domain, both EAP45 and EAP30 bound the C-terminal domain of TSG101/ESCRT-I, and EAP20 bound the N-terminal half of CHMP6/ESCRT-III. Consistent with its expected role in MVB vesicle formation, (i) human ESCRT-II localized to endosomal membranes in a VPS4-dependent fashion and (ii) depletion of EAP20/ESCRT-II and CHMP6/ESCRT-III inhibited lysosomal targeting and downregulation of the epidermal growth factor receptor, albeit to a lesser extent than depletion of TSG101/ESCRT-I. Nevertheless, HIV-1 release and infectivity were not reduced by efficient small interfering RNA depletion of EAP20/ESCRT-II or CHMP6/ESCRT-III. These observations indicate that there are probably multiple pathways for protein sorting/MVB vesicle formation in human cells and that HIV-1 does not utilize an ESCRT-II-dependent pathway to leave the cell.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • ATPases Associated with Diverse Cellular Activities
  • Adenosine Triphosphatases / metabolism
  • Animals
  • Biomarkers
  • Biosensing Techniques
  • COS Cells
  • Carrier Proteins / chemistry
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Chlorocebus aethiops
  • DNA-Binding Proteins / metabolism
  • Down-Regulation
  • Endosomal Sorting Complexes Required for Transport
  • ErbB Receptors / metabolism
  • HIV-1 / physiology*
  • Humans
  • Models, Molecular
  • Protein Binding
  • Protein Structure, Tertiary
  • Repressor Proteins / metabolism
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism
  • Two-Hybrid System Techniques
  • Ubiquitin / metabolism
  • Vacuolar Proton-Translocating ATPases
  • Vesicular Transport Proteins
  • Virion / metabolism

Substances

  • Biomarkers
  • Carrier Proteins
  • DNA-Binding Proteins
  • Endosomal Sorting Complexes Required for Transport
  • Repressor Proteins
  • Ubiquitin
  • Vesicular Transport Proteins
  • ErbB Receptors
  • Adenosine Triphosphatases
  • Vacuolar Proton-Translocating ATPases
  • ATPases Associated with Diverse Cellular Activities
  • VPS4A protein, human