title: Lentiviral Vpr usurps Cul4-DDB1[VprBP] E3 ubiquitin ligase to modulate cell cycle.
abstract: The replication of viruses depends on the cell cycle status of the infected cells. Viruses have evolved functions that alleviate restrictions imposed on their replication by the host. Vpr, an accessory factor of primate lentiviruses, arrests cells at the DNA damage checkpoint in G2 phase of the cell cycle, but the mechanism underlying this effect has remained elusive. Here we report that Vpr proteins of both the human (HIV-1) and the distantly related simian (SIVmac) immunodeficiency viruses specifically associate with a protein complex comprising subunits of E3 ubiquitin ligase assembled on Cullin-4 scaffold (Cul4-DDB1[VprBP]). We show that Vpr binding to Cul4-DDB1[VprBP] leads to increased neddylation and elevated intrinsic ubiquitin ligase activity of this E3. This effect is mediated through the VprBP subunit of the complex, which recently has been suggested to function as a substrate receptor for Cul4. We also demonstrate that VprBP regulates G1 phase and is essential for the completion of DNA replication in S phase. Furthermore, the ability of Vpr to arrest cells in G2 phase correlates with its ability to interact with Cul4-DDB1[VprBP] E3 complex. Our studies identify the Cul4-DDB1[VprBP] E3 ubiquitin ligase complex as the downstream effector of lentiviral Vpr for the induction of cell cycle arrest in G2 phase and suggest that Vpr may use this complex to perturb other aspects of the cell cycle and DNA metabolism in infected cells.
authors.affiliation: Cold Spring Harbor Laboratory, Bungtown Road, Cold Spring Harbor, NY 11724, USA.
authors.forename: Kasia
authors.initials: K
authors.lastname: Hrecka
authors.forename: Magdalena
authors.initials: M
authors.lastname: Gierszewska
authors.forename: Smita
authors.initials: S
authors.lastname: Srivastava
authors.forename: Lukasz
authors.initials: L
authors.lastname: Kozaczkiewicz
authors.forename: Selene K
authors.initials: SK
authors.lastname: Swanson
authors.forename: Laurence
authors.initials: L
authors.lastname: Florens
authors.forename: Michael P
authors.initials: MP
authors.lastname: Washburn
authors.forename: Jacek
authors.initials: J
authors.lastname: Skowronski
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D000075686:COP9 Signalosome Complex; D002352:Carrier Proteins / Q000378:metabolism; D002453:Cell Cycle / Q000502:physiology*; D002460:Cell Line; D044842:Cullin Proteins / Q000037:antagonists & inhibitors*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D039642:Eukaryotic Initiation Factors / Q000378:metabolism; D016195:G2 Phase / Q000502:physiology; D016336:Gene Products, vpr / Q000378:metabolism / Q000502:physiology*; D015497:HIV-1 / Q000502:physiology*; D006801:Humans; D011485:Protein Binding; D021122:Protein Subunits / Q000502:physiology; D015302:Simian Immunodeficiency Virus / Q000502:physiology*; D044767:Ubiquitin-Protein Ligases / Q000037:antagonists & inhibitors*; D054325:vpr Gene Products, Human Immunodeficiency Virus
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C470634:COPS6 protein, human; C114234:CUL4A protein, human; D002352:Carrier Proteins; D044842:Cullin Proteins; C091435:DDB1 protein, human; D004268:DNA-Binding Proteins; D039642:Eukaryotic Initiation Factors; D016336:Gene Products, vpr; D021122:Protein Subunits; D054325:vpr Gene Products, Human Immunodeficiency Virus; D044767:Ubiquitin-Protein Ligases; D000075686:COP9 Signalosome Complex