Structural highlights
Function
[VPR_HV1B9] Involved in the transport of the viral pre-integration (PIC) complex to the nucleus during the early stages of the infection. This function is crucial for viral infection of non-dividing macrophages. May interact with karyopherin alpha/KPNA1 and KPNA2 to increase their affinity for proteins containing basic-type nuclear localization signal, including the viral matrix protein MA, thus facilitating the translocation of the viral genome into the nucleus. May also act directly at the nuclear pore complex, by binding nucleoporins phenylalanine-glycine (FG)-repeat regions (By similarity). May target specific host proteins for degradation by the 26S proteasome. Acts by associating with the cellular CUL4A-DDB1 E3 ligase complex through direct interaction with host VPRPB/DCAF-1. This change in the E3 ligase substrate specificity would result in cell cycle arrest or apoptosis in infected cells. Prevents infected cells from undergoing mitosis and proliferating, by inducing arrest or delay in the G2 phase of the cell cycle. This arrest creates a favorable environment for maximizing viral expression and production by rendering the HIV-1 LTR transcriptionally more active. In this context, Vpr stimulates gene expression driven by the HIV-1 LTR by interacting with human SP1, TFIIB and TFIID. Cell cycle arrest reportedly occurs within hours of infection and is not blocked by antiviral agents, suggesting that it is initiated by the Vpr carried into the virion. Additionally, Vpr induces apoptosis in a cell cycle dependent manner suggesting that these two effects are mechanistically linked. Interacts with mitochondrial permeability transition pore complex (PTPC). This interaction induces a rapid dissipation of the mitochondrial transmembrane potential, and mitochondrial release of apoptogenic proteins such as cytochrome C or apoptosis inducing factors. Detected in the serum and cerebrospinal fluid of AIDS patient, Vpr may also induce cell death to bystander cells (By similarity).
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
The human immunodeficiency virus type 1, HIV-1, genome encodes a highly conserved regulatory gene product, Vpr (96 amino acids), which is incorporated into virions in quantities equivalent to those of the viral Gag protein. In infected cells, Vpr is believed to function during the early stages of HIV-1 replication (such as transcription of the proviral genome and migration of preintegration nuclear complex), blocks cells in G2 phase and triggers apoptosis. Vpr also plays a critical role in long-term AIDS disease by inducing viral infection in nondividing cells such as monocytes and macrophages. To gain deeper insight of the structure-function relationship of Vpr, the intact protein (residues 1-96) was synthesized. Its three-dimensional structure was analysed using circular dichroism and two-dimensional 1H- and 15N-NMR and refined by restrained molecular dynamics. In addition, 15N relaxation parameters (T1, T2) and heteronuclear 1H-15N NOEs were measured. The structure of the protein is characterized by a well-defined gamma turn(14-16)-alpha helix(17-33)-turn(34-36), followed by a alpha helix(40-48)-loop(49-54)-alpha helix(55-83) domain and ends with a very flexible C-terminal sequence. This structural determination of the whole intact Vpr molecule provide insights into the biological role played by this protein during the virus life cycle, as such amphipathic helices are believed to be involved in protein-lipid bilayers, protein-protein and/or protein-nucleic acid interactions.
NMR structure of the HIV-1 regulatory protein Vpr in H2O/trifluoroethanol. Comparison with the Vpr N-terminal (1-51) and C-terminal (52-96) domains.,Wecker K, Morellet N, Bouaziz S, Roques BP Eur J Biochem. 2002 Aug;269(15):3779-88. PMID:12153575[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Wecker K, Morellet N, Bouaziz S, Roques BP. NMR structure of the HIV-1 regulatory protein Vpr in H2O/trifluoroethanol. Comparison with the Vpr N-terminal (1-51) and C-terminal (52-96) domains. Eur J Biochem. 2002 Aug;269(15):3779-88. PMID:12153575
