The Tetherin/BST-2 Coiled-Coil Ectodomain Mediates Plasma Membrane Microdomain Localization and Restriction of Particle Release

• Type of Material: Article
• Authors: Jason Edward Hammonds, Emory University; Lingmei Ding, Emory University; Hin Chu, Emory University; Ken Geller, Emory University; Andrew Robbins, Emory University; Jaang-Jiun Wang, Emory University; Hong Yi, Emory University; Paul Spearman, Emory University
• Language: English
• Date: 2012-02
• Publisher: American Society for Microbiology
• Publication Version: Final Published Version
• Copyright Statement: © 2012, American Society for Microbiology. All Rights Reserved.
• Final Published Version (URL): http://dx.doi.org/10.1128%2FJVI.05906-11
• Title of Journal or Parent Work: Journal of Virology
• Volume: 86
• Issue: 4
• Start Page: 2259
• End Page: 2272
• Grant/Funding Information: The work was partly supported by the Flow Cytometry/Cell Sorting core of Children's Healthcare of Atlanta and by assistance from the Emory Center for AIDS Research (P30 AI050409).; This study was supported by NIH AI058828 and by funds from Children's Healthcare of Atlanta.
• Research Categories: Biology, Virology

Abstract

Tetherin/BST-2 forms a proteinaceous tether that restricts the release of a number of enveloped viruses following viral budding. Tetherin is an unusual membrane glycoprotein with two membrane anchors and an extended coiled-coil ectodomain. The ectodomain itself forms an imperfect coil that may undergo conformational shifts to accommodate membrane dynamics during the budding process. The coiled-coil ectodomain is required for restriction, but precisely how it contributes to the restriction of particle release remains under investigation. In this study, mutagenesis of the ectodomain was used to further define the role of the coiled-coil ectodomain in restriction. Scanning mutagenesis throughout much of the ectodomain failed to disrupt the ability of tetherin to restrict HIV particle release, indicating a high degree of plasticity. Targeted N- and C-terminal substitutions disrupting the coiled coil led to both a loss of restriction and an alteration of subcellular distribution. Two ectodomain mutants deficient in restriction were endocytosed inefficiently, and the levels of these mutants on the cell surface were significantly enhanced. An ectodomain mutant with four targeted serine substitutions (4S) failed to cluster in membrane microdomains, was deficient in restriction of particle release, and exhibited an increase in lateral mobility on the membrane. These results suggest that the tetherin ectodomain contributes to microdomain localization and to constrained lateral mobility. We propose that focal clustering of tetherin via ectodomain interactions plays a role in restriction of particle release.