title: Citron kinase enhances ubiquitination of HIV-1 Gag protein and intracellular HIV-1 budding.
abstract: Assembly and budding of human immunodeficiency virus type 1 (HIV-1) particles is a complex process involving a number of host proteins. We have previously reported that the RhoA effector citron kinase enhances HIV-1 production. However, the underlying mechanism is not clear. In this study, we found that citron kinase interacted with HIV-1 Gag protein via its zinc finger and leucine zipper domains. Electron microscopy analysis revealed that citron kinase induced viral particle assembly in multivesicular bodies (MVBs). Citron kinase enhanced ubiquitination of HIV-1 Gag protein. Knockdown of Nedd4L, a member of the HECT ubiquitin E3 ligase family, partly decreased the ability of citron kinase to enhance HIV-1 production and reduced ubiquitination of HIV-1 Gag. Interestingly, the function of citron kinase to promote HIV-1 budding was severely impaired when endogenous ALIX was knocked down. Overexpression of the AAA-type ATPase VPS4 eliminated citron-kinase-mediated enhancement of HIV-1 production. Our results suggest that citron kinase interacts with HIV-1 Gag and enhances HIV-1 production by promoting Gag ubiquitination and inducing viral release via the MVB pathway.
authors.affiliation: Institute of Medicinal Biotechnology, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China.
authors.forename: Jiwei
authors.initials: J
authors.lastname: Ding
authors.affiliation: Institute of Medicinal Biotechnology, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China.
authors.forename: Jianyuan
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Center for Biological Imaging, National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Sun
authors.affiliation: Institute of Medicinal Biotechnology, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China.
authors.forename: Zeyun
authors.initials: Z
authors.lastname: Mi
authors.affiliation: Institute of Medicinal Biotechnology, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China. shancen@imb.pumc.edu.cn.
authors.forename: Shan
authors.identifier: http://orcid.org/0000-0003-1942-4885
authors.initials: S
authors.lastname: Cen
mesh_terms: D002135:Calcium-Binding Proteins; D018797:Cell Cycle Proteins; D056827:Endosomal Sorting Complexes Required for Transport; D015967:Gene Expression Regulation, Viral / Q000502:physiology*; D057809:HEK293 Cells; D015497:HIV-1 / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D000075702:Nedd4 Ubiquitin Protein Ligases; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases; D054875:Ubiquitination / Q000187:drug effects; D014779:Virus Replication / Q000502:physiology*; D054301:gag Gene Products, Human Immunodeficiency Virus / Q000235:genetics / Q000378:metabolism*
chemical_list: D002135:Calcium-Binding Proteins; D018797:Cell Cycle Proteins; D056827:Endosomal Sorting Complexes Required for Transport; D047908:Intracellular Signaling Peptides and Proteins; C117020:PDCD6IP protein, human; D054301:gag Gene Products, Human Immunodeficiency Virus; D000075702:Nedd4 Ubiquitin Protein Ligases; C000618485:Nedd4L protein, human; D044767:Ubiquitin-Protein Ligases; C115635:citron-kinase; D017346:Protein Serine-Threonine Kinases