Open AccessImportin-α Promotes Passage through the Nuclear Pore Complex of Human Immunodeficiency Virus Type 1 Vpr
Author(s) -
Masakazu Kamata,
Yuko Nitahara-Kasahara,
Yoichi Miyamoto,
Yoshihiro Yoneda,
Yoko Aida
Publication year - 2005
Publication title -
journal of virology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.617
H-Index - 292
eISSN - 1070-6321
pISSN - 0022-538X
DOI - 10.1128/jvi.79.6.3557-3564.2005
Subject(s) - importin , nuclear transport , nuclear localization sequence , biology , nuclear pore , nls , nuclear protein , microbiology and biotechnology , nucleus , cell nucleus , green fluorescent protein , fusion protein , virology , biochemistry , recombinant dna , gene , transcription factor
Viral protein R (Vpr) of human immunodeficiency virus type 1 has potent karyophilic properties, but details of the mechanism by which it enters the nucleus remain to be clarified. We reported previously that two regions, located between residues 17 and 34 (alphaH1) and between residues 46 and 74 (alphaH2), are indispensable for the nuclear localization of Vpr. Here, we reveal that a chimeric protein composed of the nuclear localization signal of Vpr, glutathione S-transferase, and green fluorescent protein was localized at the nuclear envelope and then entered the nucleus upon addition of importin-alpha. An in vitro transport assay using a series of derivatives of importin-alpha demonstrated that the carboxyl terminus was required for this nuclear import process. We also showed that Vpr interacts with importin-alpha through alphaH1 and alphaH2; only the interaction via alphaH1 is indispensable for the nuclear entry of Vpr. These observations indicate that importin-alpha functions as a mediator for the nuclear entry of Vpr.