ALIX is recruited temporarily into HIV-1 budding sites at the end of gag assembly

Pei-I Ku; Mourad Bendjennat; Jeff Ballew; Michael B Landesman; Saveez Saffarian

doi:10.1371/journal.pone.0096950

ALIX is recruited temporarily into HIV-1 budding sites at the end of gag assembly

PLoS One. 2014 May 16;9(5):e96950. doi: 10.1371/journal.pone.0096950. eCollection 2014.

Authors

Pei-I Ku¹, Mourad Bendjennat¹, Jeff Ballew¹, Michael B Landesman¹, Saveez Saffarian²

Affiliations

¹ Department of Physics and Astronomy, University of Utah, Salt Lake City, Utah, United States of America.
² Department of Physics and Astronomy, University of Utah, Salt Lake City, Utah, United States of America; Center for Cell and Genome Science, University of Utah, Salt Lake City, Utah, United States of America; Department of Biology, University of Utah, Salt Lake City, Utah, United States of America.

Abstract

Polymerization of Gag on the inner leaflet of the plasma membrane drives the assembly of Human Immunodeficiency Virus 1 (HIV-1). Gag recruits components of the endosomal sorting complexes required for transport (ESCRT) to facilitate membrane fission and virion release. ESCRT assembly is initiated by recruitment of ALIX and TSG101/ESCRT-I, which bind directly to the viral Gag protein and then recruit the downstream ESCRT-III and VPS4 factors to complete the budding process. In contrast to previous models, we show that ALIX is recruited transiently at the end of Gag assembly, and that most ALIX molecules are recycled into the cytosol as the virus buds, although a subset remains within the virion. Our experiments imply that ALIX is recruited to the neck of the assembling virion and is mostly recycled after virion release.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

ATPases Associated with Diverse Cellular Activities
Calcium-Binding Proteins / metabolism*
Cell Cycle Proteins / metabolism*
DNA-Binding Proteins / metabolism
DNA-Binding Proteins / physiology*
Endosomal Sorting Complexes Required for Transport / metabolism*
Endosomal Sorting Complexes Required for Transport / physiology*
HEK293 Cells
HIV-1 / physiology*
HeLa Cells
Humans
Microscopy, Confocal
Transcription Factors / metabolism
Transcription Factors / physiology*
Vacuolar Proton-Translocating ATPases / metabolism
Virus Assembly / physiology*
gag Gene Products, Human Immunodeficiency Virus / metabolism*

Substances

Calcium-Binding Proteins
Cell Cycle Proteins
DNA-Binding Proteins
Endosomal Sorting Complexes Required for Transport
PDCD6IP protein, human
Transcription Factors
Tsg101 protein
gag Gene Products, Human Immunodeficiency Virus
Vacuolar Proton-Translocating ATPases
ATPases Associated with Diverse Cellular Activities
VPS4A protein, human

Grants and funding

This work was supported by NSF grants 1121972 (SS). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.