Functional and Structural Characterization of Synthetic HIV-1 Vpr That Transduces Cells, Localizes to the Nucleus, and Induces G2 Cell Cycle Arrest

Autor: Uwe Tessmer, Jeffrey B. Kopp, Warner C. Greene, Karsten Bruns, Peter Henklein, Ulrich Schubert, Michael P. Sherman, Kai Licha, Victor Wray, Carlos M. C. de Noronha
Rok vydání: 2000
Předmět:
G2 Phase
Protein Folding
Magnetic Resonance Spectroscopy
Cell cycle checkpoint
viruses
Blotting
Western
Molecular Sequence Data
Biology
Biochemistry
Protein Structure
Secondary
Protein structure
Sequence Analysis
Protein
Extracellular
medicine
Humans
Scattering
Radiation
Amino Acid Sequence
Protein Structure
Quaternary
Receptor
Molecular Biology
Cell Nucleus
Circular Dichroism
Gene Products
vpr
Macrophages
virus diseases
Trifluoroethanol
vpr Gene Products
Human Immunodeficiency Virus
Cell Biology
Hydrogen-Ion Concentration
biochemical phenomena
metabolism
and nutrition
Peptide Fragments
Transport protein
Cell biology
Protein Transport
Cell nucleus
medicine.anatomical_structure
Spectrometry
Mass
Matrix-Assisted Laser Desorption-Ionization
HIV-1
Protein folding
Nuclear transport
Dimerization
HeLa Cells
Zdroj: Journal of Biological Chemistry. 275:32016-32026
ISSN: 0021-9258
Popis: Human immunodeficiency virus (HIV) Vpr contributes to nuclear import of the viral pre-integration complex and induces G(2) cell cycle arrest. We describe the production of synthetic Vpr that permitted the first studies on the structure and folding of the full-length protein. Vpr is unstructured at neutral pH, whereas under acidic conditions or upon addition of trifluorethanol it adopts alpha-helical structures. Vpr forms dimers in aqueous trifluorethanol, whereas oligomers exist in pure water. (1)H NMR spectroscopy allows the signal assignment of N- and C-terminal amino acid residues; however, the central section of the molecule is obscured by self-association. These findings suggest that the in vivo folding of Vpr may require structure-stabilizing interacting factors such as previously described interacting cellular and viral proteins or nucleic acids. In biological studies we found that Vpr is efficiently taken up from the extracellular medium by cells in a process that occurs independent of other HIV-1 proteins and appears to be independent of cellular receptors. Following cellular uptake, Vpr is efficiently imported into the nucleus of transduced cells. Extracellular addition of Vpr induces G(2) cell cycle arrest in dividing cells. Together, these findings raise the possibility that circulating forms of Vpr observed in HIV-infected patients may exert biological effects on a broad range of host target cells.
Databáze: OpenAIRE
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