Open Access
Multimerization of Human Immunodeficiency Virus Type 1 Gag Promotes Its Localization to Barges, Raft-Like Membrane Microdomains
Author(s) -
O. Wolf Lindwasser,
Marilyn D. Resh
Publication year - 2001
Publication title -
journal of virology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.617
H-Index - 292
eISSN - 1070-6321
pISSN - 0022-538X
DOI - 10.1128/jvi.75.17.7913-7924.2001
Subject(s) - myristoylation , raft , group specific antigen , biology , microbiology and biotechnology , rab , virus , virology , chemistry , gtpase , phosphorylation , organic chemistry , copolymer , polymer
The Gag polyprotein of human immunodeficiency virus type 1 (HIV-1) organizes the assembly of nascent virions at the plasma membrane of infected cells. Here we demonstrate that a population of Gag is present in distinct raft-like membrane microdomains that we have termed "barges." Barges have a higher density than standard rafts, most likely due to the presence of oligomeric Gag-Gag assembly complexes. The regions of the Gag protein responsible for barge targeting were mapped by examining the flotation behavior of wild-type and mutant proteins on Optiprep density gradients. N-myristoylation of Gag was necessary for association with barges. Removal of the NC and p6 domains shifted much of the Gag from barges into typical raft fractions. These data are consistent with a model in which multimerization of myristoylated Gag proteins drives association of Gag oligomers into raft-like barges. The functional significance of barge association was revealed by several lines of evidence. First, Gag isolated from virus-like particles was almost entirely localized in barges. Moreover, a comparison of wild-type Gag with Fyn(10)Gag, a chimeric protein containing the N-terminal sequence of Fyn, revealed that Fyn(10)Gag exhibited increased affinity for barges and a two- to fourfold increase in particle production. These results imply that association of Gag with raft-like barge membrane microdomains plays an important role in the HIV-1 assembly process.