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Glycobiology. 2014 Nov;24(11):1022-35. doi: 10.1093/glycob/cwu064. Epub 2014 Jul 4.

Galectin-3 promotes HIV-1 budding via association with Alix and Gag p6.

Author information

1
Department of Medical Laboratory Science and Biotechnology Institute of Biomedical Sciences Center for AIDS Prevention and Research.
2
Institute of Biomedical Sciences.
3
Center for AIDS Prevention and Research.
4
Institute of Biomedical Sciences Department of Dermatology, University of California at Davis, Davis, USA.
5
Department of Optics and Photonics, National Central University, Chung-Li, Taiwan.
6
Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan.
7
Department of Microbiology, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan Center for AIDS Prevention and Research Department of Microbiology, School of Medicine, National Yang-Ming University, Taipei, Taiwan ftliu@ibms.sinica.edu.tw arthur@kmu.edu.tw hchen9@gmail.com.
8
Institute of Biomedical Sciences Department of Dermatology, University of California at Davis, Davis, USA ftliu@ibms.sinica.edu.tw arthur@kmu.edu.tw hchen9@gmail.com.

Abstract

Galectin-3 has been reported to regulate the functions of a number of immune cell types. We previously reported that galectin-3 is translocated to immunological synapses in T cells upon T-cell receptor engagement, where it associates with ALG-2-interacting protein X (Alix). Alix is known to coordinate with the endosomal sorting complex required for transport (ESCRT) to promote human immunodeficiency virus (HIV)-1 virion release. We hypothesized that galectin-3 plays a role in HIV-1 viral budding. Cotransfection of cells of the Jurkat T line with galectin-3 and HIV-1 plasmids resulted in increased HIV-1 budding, and suppression of galectin-3 expression by RNAi in Hut78 and primary CD4+ T cells led to reduced HIV-1 budding. We used immunofluorescence microscopy to observe the partial colocalization of galectin-3, Alix and Gag in HIV-1-infected cells. Results from co-immunoprecipitation experiments indicate that galectin-3 expression promotes Alix-Gag p6 association, whereas the results of Alix knockdown suggest that galectin-3 promotes HIV-1 budding through Alix. HIV-1 particles released from galectin-3-expressing cells acquire the galectin-3 protein in an Alix-dependent manner, with proteins primarily residing inside the virions. We also found that the galectin-3 N-terminal domain interacts with the proline-rich region of Alix. Collectively, these results suggest that endogenous galectin-3 facilitates HIV-1 budding by promoting the Alix-Gag p6 association.

KEYWORDS:

Alix; HIV-1; galectin-3; viral budding

PMID:
24996823
PMCID:
PMC4181451
DOI:
10.1093/glycob/cwu064
[Indexed for MEDLINE]
Free PMC Article

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