title: Cyclophilin A interacts with HIV-1 Vpr and is required for its functional expression.
abstract: Viral protein R (Vpr) of human immunodeficiency virus, type 1 (HIV-1) is the major virion-associated accessory protein that affects a number of biological functions in the retroviral life cycle, including promotion of the transport of the preintegration complex into the nucleus and the induction of G2 host cell cycle arrest. Our recent investigation of the conformational heterogeneity of the proline residues in the N terminus of Vpr suggested a functional interaction between Vpr and a host peptidylprolyl cis/trans isomerase (PPIase) that might regulate the cis/trans interconversion of the imidic bond within the conserved proline residues of Vpr in vivo. Using surface plasmon resonance spectroscopy, Far Western blot, and pulldown experiments a physical interaction of Vpr with the major host PPIase cyclophilin A (CypA) is now demonstrated. The interaction domain involves the N-terminal region of Vpr including an essential role for proline in position 35. The CypA inhibitor cyclosporin A and non-immunosuppressive PPIase inhibitors such as NIM811 and sanglifehrin A block expression of Vpr without affecting pre- or post-translational events such as transcription, intracellular transport, or virus incorporation of Vpr. Similarly to CypA inhibition, Vpr expression is also reduced in HIV-1 infected CypA-/- knock-out T cells. This study thus shows that in addition to the interaction between CypA and HIV-1 capsid occurring during early steps in virus replication, CypA is also important for the de novo synthesis of Vpr and that in the absence of CypA activity, the Vpr-mediated cell cycle arrest is completely lost in HIV-1-infected T cells.
authors.affiliation: Heinrich-Pette-Institute of Experimental Virology and Immunology, University of Hamburg, D-20251 Hamburg, Germany.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Zander
authors.forename: Michael P
authors.initials: MP
authors.lastname: Sherman
authors.forename: Uwe
authors.initials: U
authors.lastname: Tessmer
authors.forename: Karsten
authors.initials: K
authors.lastname: Bruns
authors.forename: Victor
authors.initials: V
authors.lastname: Wray
authors.forename: Alexander T
authors.initials: AT
authors.lastname: Prechtel
authors.forename: Evelyn
authors.initials: E
authors.lastname: Schubert
authors.forename: Peter
authors.initials: P
authors.lastname: Henklein
authors.forename: Jeremy
authors.initials: J
authors.lastname: Luban
authors.forename: Jason
authors.initials: J
authors.lastname: Neidleman
authors.forename: Warner C
authors.initials: WC
authors.lastname: Greene
authors.forename: Ulrich
authors.initials: U
authors.lastname: Schubert
mesh_terms: D000595:Amino Acid Sequence; D015152:Blotting, Northern; D015153:Blotting, Western; D021984:Cyclophilin A / Q000737:chemistry* / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004220:Disulfides; D005434:Flow Cytometry; D016195:G2 Phase; D016336:Gene Products, vpr / Q000096:biosynthesis / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D019169:Jurkat Cells; D008969:Molecular Sequence Data; D010957:Plasmids / Q000378:metabolism; D011392:Proline / Q000737:chemistry; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D020349:Surface Plasmon Resonance; D013601:T-Lymphocytes / Q000378:metabolism; D013997:Time Factors; D014162:Transfection
chemical_list: D004220:Disulfides; D016336:Gene Products, vpr; D011994:Recombinant Proteins; D004247:DNA; D011392:Proline; D021984:Cyclophilin A