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HIV‐1 Vpu Antagonizes BST‐2 by Interfering Mainly with the Trafficking of Newly Synthesized BST‐2 to the Cell Surface
Author(s) -
Dubé Mathieu,
Paquay Catherine,
Roy Bibhuti Bhusan,
Bego Mariana G.,
Mercier Johanne,
Cohen Éric A.
Publication year - 2011
Publication title -
traffic
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.677
H-Index - 130
eISSN - 1600-0854
pISSN - 1398-9219
DOI - 10.1111/j.1600-0854.2011.01277.x
Subject(s) - endosome , tetherin , endocytic cycle , microbiology and biotechnology , biology , jurkat cells , cell , intracellular , endocytosis , hela , cell membrane , downregulation and upregulation , transport protein , virology , t cell , virus , biochemistry , viral envelope , immunology , immune system , gene
Bone marrow stromal cell antigen‐2 (BST‐2) inhibits human immunodeficiency virus type 1 (HIV‐1) release by cross‐linking nascent virions on infected cell surface. HIV‐1 Vpu is thought to antagonize BST‐2 by downregulating its surface levels via a mechanism that involves intracellular sequestration and lysosomal degradation. Here, we investigated the functional importance of cell‐surface BST‐2 downregulation and the BST‐2 pools targeted by Vpu using an inducible proviral expression system. Vpu established a surface BST‐2 equilibrium at ∼60% of its initial levels within 6 h, a condition that coincided with detection of viral release. Analysis of BST‐2 post‐endocytic trafficking revealed that the protein is engaged in a late endosomal pathway independent of Vpu. While Vpu moderately enhanced cell‐surface BST‐2 clearance, it strongly affected the protein resupply to the plasma membrane via newly synthesized proteins. Noticeably, Vpu affected clearance of surface BST‐2 more substantially in Jurkat T cells than in HeLa cells, suggesting a cell‐dependent impact of Vpu on the pool of surface BST‐2. Collectively, our data reveal that Vpu imposes a new BST‐2 equilibrium, incompatible with efficient restriction of HIV‐1 release, by combining an acceleration of surface BST‐2 natural clearance, whose degree might be cell‐type dependent, to a severe impairment of the protein resupply to the plasma membrane.