title: Galectin-3 promotes HIV-1 budding via association with Alix and Gag p6.
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.
authors.affiliation: Department of Medical Laboratory Science and Biotechnology Institute of Biomedical Sciences Center for AIDS Prevention and Research.
authors.forename: Sheng-Fan
authors.initials: SF
authors.lastname: Wang
authors.affiliation: Institute of Biomedical Sciences.
authors.forename: Ching-Han
authors.initials: CH
authors.lastname: Tsao
authors.affiliation: Center for AIDS Prevention and Research.
authors.forename: Yu-Ting
authors.initials: YT
authors.lastname: Lin
authors.affiliation: Institute of Biomedical Sciences Department of Dermatology, University of California at Davis, Davis, USA.
authors.forename: Daniel K
authors.initials: DK
authors.lastname: Hsu
authors.affiliation: Institute of Biomedical Sciences.
authors.forename: Meng-Lin
authors.initials: ML
authors.lastname: Chiang
authors.affiliation: Institute of Biomedical Sciences.
authors.forename: Chia-Hui
authors.initials: CH
authors.lastname: Lo
authors.affiliation: Department of Optics and Photonics, National Central University, Chung-Li, Taiwan.
authors.forename: Fan-Ching
authors.initials: FC
authors.lastname: Chien
authors.affiliation: Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan.
authors.forename: Peilin
authors.initials: P
authors.lastname: Chen
authors.affiliation: 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.
authors.forename: Yi-Ming
authors.initials: YM
authors.lastname: Arthur Chen
authors.affiliation: 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.
authors.forename: Huan-Yuan
authors.initials: HY
authors.lastname: Chen
authors.affiliation: 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.
authors.forename: Fu-Tong
authors.initials: FT
authors.lastname: Liu
mesh_terms: D002135:Calcium-Binding Proteins / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000502:physiology*; D056827:Endosomal Sorting Complexes Required for Transport / Q000502:physiology*; D037502:Galectin 3 / Q000502:physiology*; D015497:HIV-1 / Q000502:physiology*; D011485:Protein Binding; D014779:Virus Replication / Q000502:physiology*; D054301:gag Gene Products, Human Immunodeficiency Virus / Q000502:physiology*
chemical_list: D002135:Calcium-Binding Proteins; D018797:Cell Cycle Proteins; D056827:Endosomal Sorting Complexes Required for Transport; D037502:Galectin 3; C117020:PDCD6IP protein, human; D054301:gag Gene Products, Human Immunodeficiency Virus; C083002:p6 gag protein, Human immunodeficiency virus 1
keywords: Alix; HIV-1; galectin-3; viral budding