This Article Full Text Full Text (PDF) Supplemental material Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Chen, S. S.-L. Articles by Huang, S.-C. Search for Related Content PubMed PubMed Citation Articles by Chen, S. S.-L. Articles by Huang, S.-C.

 Previous Article  |  Next Article 

Journal of Virology, January 2009, p. 870-883, Vol. 83, No. 2
0022-538X/09/$08.00+0     doi:10.1128/JVI.01088-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Identification of the LWYIK Motif Located in the Human Immunodeficiency Virus Type 1 Transmembrane gp41 Protein as a Distinct Determinant for Viral Infection ^,

Steve S.-L. Chen,^1* Polung Yang,¹ Po-Yuan Ke,¹ Hsiao-Fen Li,¹ Woan-Eng Chan,¹ Ding-Kwo Chang,² Chin-Kai Chuang,³ Yu Tsai,¹ and Shu-Chen Huang¹

Institute of Biomedical Sciences,¹ Institute of Chemistry, Academia Sinica, Taipei 11529,² Division of Biotechnology, Animal Technology Institute Taiwan, Miaoli 35053, Taiwan, Republic of China³

Received 23 May 2008/ Accepted 25 October 2008

The highly conserved LWYIK motif located immediately proximal to the membrane-spanning domain of the gp41 transmembrane protein of human immunodeficiency virus type 1 has been proposed as being important for the surface envelope (Env) glycoprotein's association with lipid rafts and gp41-mediated membrane fusion. Here we employed substitution and deletion mutagenesis to understand the role of this motif in the virus life cycle. None of the mutants examined affected the synthesis, precursor processing, CD4 binding, oligomerization, or cell surface expression of the Env, nor did they alter Env incorporation into the virus. All of the mutants, particularly the YI, IK, and LWYIK mutants, in which the indicated residues were deleted, exhibited greatly reduced one-cycle viral replication and the Env trans-complementation ability. All of these deletion mutant proteins were still localized in the lipid rafts. With the exception of the Trp-to-Ala (WA) mutant, which exhibited reduced viral infectivity albeit with normal membrane fusion, all mutants displayed loss of some or almost all of the membrane fusion ability. Although these deletion mutants partially inhibited in trans wild-type (WT) Env-mediated fusion, they were more effective in dominantly interfering with WT Env-mediated viral entry when coexpressed with the WT Env, implying a role of this motif in postfusion events as well. Both T20 and L43L peptides derived from the two gp41 extracellular C- and N-terminal -helical heptad repeats, respectively, inhibited WT and LWYIK Env-mediated viral entry with comparable efficacies. Biotin-tagged T20 effectively captured both the fusion-active, prehairpin intermediates of WT and mutant gp41 upon CD4 activation. Env without the deletion of the LWYIK motif still effectively mediated lipid mixing but inhibited content mixing. Our study demonstrates that the immediate membrane-proximal LWYIK motif acts as a unique and distinct determinant located in the gp41 C-terminal ectodomain by promoting enlargement of fusion pores and postfusion activities.

---

* Corresponding author. Mailing address: Institute of Biomedical Sciences, Academia Sinica, 128 Yen-Chiu-Yuan Road, Section 2, Nankang, Taipei 11529, Taiwan, Republic of China. Phone: 886-2-2652-3933. Fax: 886-2-2652-3073. E-mail: schen{at}ibms.sinica.edu.tw

Published ahead of print on 5 November 2008.

Supplemental material for this article may be found at http://jvi.asm.org/.

---

Journal of Virology, January 2009, p. 870-883, Vol. 83, No. 2
0022-538X/09/$08.00+0     doi:10.1128/JVI.01088-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.