title: Interaction of transportin-SR2 with Ras-related nuclear protein (Ran) GTPase.
abstract: The human immunodeficiency virus type 1 (HIV-1) and other lentiviruses are capable of infecting non-dividing cells and, therefore, need to be imported into the nucleus before integration into the host cell chromatin. Transportin-SR2 (TRN-SR2, Transportin-3, TNPO3) is a cellular karyopherin implicated in nuclear import of HIV-1. A model in which TRN-SR2 imports the viral preintegration complex into the nucleus is supported by direct interaction between TRN-SR2 and HIV-1 integrase (IN). Residues in the C-terminal domain of HIV-1 IN that mediate binding to TRN-SR2 were recently delineated. As for most nuclear import cargoes, the driving force behind HIV-1 preintegration complex import is likely a gradient of the GDP- and GTP-bound forms of Ran, a small GTPase. In this study we offer biochemical and structural characterization of the interaction between TRN-SR2 and Ran. By size exclusion chromatography we demonstrate stable complex formation of TRN-SR2 and RanGTP in solution. Consistent with the behavior of normal nuclear import cargoes, HIV-1 IN is released from the complex with TRN-SR2 by RanGTP. Although in concentrated solutions TRN-SR2 by itself was predominantly present as a dimer, the TRN-SR2-RanGTP complex was significantly more compact. Further analysis supported a model wherein one monomer of TRN-SR2 is bound to one monomer of RanGTP. Finally, we present a homology model of the TRN-SR2-RanGTP complex that is in excellent agreement with the experimental small angle x-ray scattering data.
authors.affiliation: From the Laboratory for Molecular Virology and Gene Therapy and.
authors.forename: Oliver
authors.initials: O
authors.lastname: Taltynov
authors.affiliation: From the Laboratory for Molecular Virology and Gene Therapy and.
authors.forename: Jonas
authors.initials: J
authors.lastname: Demeulemeester
authors.affiliation: From the Laboratory for Molecular Virology and Gene Therapy and.
authors.forename: Frauke
authors.initials: F
authors.lastname: Christ
authors.affiliation: From the Laboratory for Molecular Virology and Gene Therapy and.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: De Houwer
authors.affiliation: Laboratory for Biocrystallography, KU Leuven, B-3000 Leuven, Belgium.
authors.forename: Vicky G
authors.initials: VG
authors.lastname: Tsirkone
authors.affiliation: From the Laboratory for Molecular Virology and Gene Therapy and.
authors.forename: Melanie
authors.initials: M
authors.lastname: Gerard
authors.affiliation: Laboratory for Biocrystallography, KU Leuven, B-3000 Leuven, Belgium.
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Weeks
authors.affiliation: Laboratory for Biocrystallography, KU Leuven, B-3000 Leuven, Belgium.
authors.forename: Sergei V
authors.initials: SV
authors.lastname: Strelkov
authors.affiliation: From the Laboratory for Molecular Virology and Gene Therapy and. Electronic address: zeger.debyser@med.kuleuven.be.
authors.forename: Zeger
authors.initials: Z
authors.lastname: Debyser
mesh_terms: D021581:Active Transport, Cell Nucleus / Q000235:genetics; D019427:HIV Integrase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015497:HIV-1; D006801:Humans; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D028961:beta Karyopherins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D020931:ran GTP-Binding Protein / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D046912:Multiprotein Complexes; C120587:RAN protein, human; C546476:TNPO3 protein, human; D028961:beta Karyopherins; D019427:HIV Integrase; D020931:ran GTP-Binding Protein
keywords: GTPase; HIV-1; Homology Modeling; Host-Pathogen Interactions; Nuclear Transport; Protein-Protein Interactions; X-ray Scattering