title: Human immunodeficiency virus type 1 Vpr binds to the N lobe of the Wee1 kinase domain and enhances kinase activity for CDC2.
abstract: Human immunodeficiency virus type 1 Vpr is a virion-associated accessory protein that has multiple activities within an infected cell. One of the most dramatic effects of Vpr is the induction of cell cycle arrest at the G(2)/M boundary, followed by apoptosis. This effect has implications for CD4(+) cell loss in AIDS. In normal cell cycle regulation, Wee1, a key regulator for G(2)-M progression, phosphorylates Tyr15 on Cdc2 and thereby blocks the progression of cells into M phase. We demonstrate that Vpr physically interacts with Wee1 at the N lobe of the kinase domain analogous to that present in other kinases. This interaction with Vpr enhances Wee1 kinase activity for Cdc2. Overexpression of Wee1 kinase-deficient mutants competes for Vpr-mediated cell cycle arrest, and deletion of the region of Wee1 that binds Vpr abrogates that competition. However, the Vpr mutants I74P and I81P, which fail to induce G(2) arrest, can bind to and increase the kinase activity of Wee1 to the same extent as wild-type Vpr. Therefore, we conclude that the binding of Vpr to Wee1 is not sufficient for Vpr to activate the G(2) checkpoint, and it may reflect an independent function of Vpr.
authors.affiliation: Department of Microbiology, Immunology and Molecular Genetics, University of California at Los Angeles, David Geffen School of Medicine, 615 Charles E. Young Dr. South, BSRB 173, Los Angeles, CA 90095, USA.
authors.forename: Masakazu
authors.initials: M
authors.lastname: Kamata
authors.forename: Nobumoto
authors.initials: N
authors.lastname: Watanabe
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Nagaoka
authors.forename: Irvin S Y
authors.initials: IS
authors.lastname: Chen
mesh_terms: D016203:CDC2 Protein Kinase / Q000302:isolation & purification / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000032:analysis / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002460:Cell Line; D016195:G2 Phase; D016336:Gene Products, vpr / Q000235:genetics / Q000378:metabolism*; D005982:Glutathione Transferase / Q000378:metabolism; D015497:HIV-1; D006367:HeLa Cells; D006801:Humans; D007668:Kidney / Q000166:cytology; D009687:Nuclear Proteins / Q000032:analysis / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D010957:Plasmids; D017434:Protein Structure, Tertiary; D011505:Protein-Tyrosine Kinases / Q000032:analysis / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014162:Transfection
chemical_list: D018797:Cell Cycle Proteins; D016336:Gene Products, vpr; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; D005982:Glutathione Transferase; D011505:Protein-Tyrosine Kinases; C499349:WEE1 protein, human; D016203:CDC2 Protein Kinase