Structural highlights
Function
[VPR_HV1RH] 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).
Publication Abstract from PubMed
Human immunodeficiency virus type 1 protein R (HIV-1 Vpr) promotes nuclear entry of viral nucleic acids in nondividing cells, causes G2 cell cycle arrest and is involved in cellular differentiation and cell death. Also, Vpr subcellular localization is as variable as its functions. It is known that, consistent with its role in nuclear transport, Vpr localizes to the nuclear envelope of human cells. Further, a reported ion channel activity of Vpr obviously is dependent on its localization in or at membranes. We focused our structural studies on the secondary structure of a peptide consisting of residues 13-33 of HIV-1 Vpr in micelles. Employing nuclear magnetic resonance and circular dichroism spectroscopy we found this part of Vpr, known to be essential for nuclear localization, to be almost completely alpha helical. Our results provide structural data suggesting residues 13-33 of Vpr to form an amphipathic, leucine-zipper-like alpha helix that serves as a basis for interactions with a variety of viral and cellular factors.
Solution structure of human immunodeficiency virus type 1 Vpr(13-33) peptide in micelles.,Engler A, Stangler T, Willbold D Eur J Biochem. 2001 Jan;268(2):389-95. PMID:11168374[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Engler A, Stangler T, Willbold D. Solution structure of human immunodeficiency virus type 1 Vpr(13-33) peptide in micelles. Eur J Biochem. 2001 Jan;268(2):389-95. PMID:11168374
