Importin subunit alpha-7 explained

Importin subunit alpha-7 is a protein that in humans is encoded by the KPNA6 gene.^[1]

Nucleocytoplasmic transport, a signal- and energy-dependent process, takes place through nuclear pore complexes embedded in the nuclear envelope. The import of proteins containing a nuclear localization signal (NLS) requires the NLS import receptor, a heterodimer of importin alpha and beta subunits also known as karyopherins. Importin alpha binds the NLS-containing cargo in the cytoplasm and importin beta docks the complex at the cytoplasmic side of the nuclear pore complex. In the presence of nucleoside triphosphates and the small GTP binding protein Ran, the complex moves into the nuclear pore complex and the importin subunits dissociate. Importin alpha enters the nucleoplasm with its passenger protein and importin beta remains at the pore. The protein encoded by this gene is a member of the importin alpha family.^[2]

Further reading

• Bukrinsky MI, Haffar OK . HIV-1 nuclear import: in search of a leader . Front. Biosci. . 2 . d578–87 . 2004 . 4 . 9366553 . 10.2741/A213. free .
• Bukrinsky MI, Haffar OK . HIV-1 nuclear import: matrix protein is back on center stage, this time together with Vpr . Mol. Med. . 4 . 3 . 138–43 . 1998 . 9562972 . 10.1007/BF03401911. 2230352 .
• Christophe D, Christophe-Hobertus C, Pichon B . Nuclear targeting of proteins: how many different signals? . Cell. Signal. . 12 . 5 . 337–41 . 2000 . 10822175 . 10.1016/S0898-6568(00)00077-2 .
• Chook YM, Blobel G . Karyopherins and nuclear import . Curr. Opin. Struct. Biol. . 11 . 6 . 703–15 . 2002 . 11751052 . 10.1016/S0959-440X(01)00264-0 .
• Bukrinsky MI . Active nuclear import of human immunodeficiency virus type 1 preintegration complexes . Proc. Natl. Acad. Sci. U.S.A. . 89 . 14 . 6580–4 . 1992 . 1631159 . 10.1073/pnas.89.14.6580 . 49545 . vanc. Sharova N . Dempsey MP . 3 . Stanwick . TL . Bukrinskaya . AG . Haggerty . S . Stevenson . M . 1992PNAS...89.6580B . free .
• Sharova N, Bukrinskaya A . p17 and p17-containing gag precursors of input human immunodeficiency virus are transported into the nuclei of infected cells . AIDS Res. Hum. Retroviruses . 7 . 3 . 303–6 . 1991 . 2064827 . 10.1089/aid.1991.7.303 .
• Di Marzio P . Mutational analysis of cell cycle arrest, nuclear localization and virion packaging of human immunodeficiency virus type 1 Vpr . J. Virol. . 69 . 12 . 7909–16 . 1996 . 7494303 . 189735 . vanc. Choe S . Ebright M . 3 . Knoblauch . R . Landau . NR . 10.1128/JVI.69.12.7909-7916.1995 .
• Gallay P . HIV nuclear import is governed by the phosphotyrosine-mediated binding of matrix to the core domain of integrase . Cell . 83 . 4 . 569–76 . 1995 . 7585960 . 10.1016/0092-8674(95)90097-7 . vanc. Swingler S . Song J . 3 . Bushman . Frederic . Trono . Didier . 15536328 . free.
• Freed EO, Englund G, Martin MA . Role of the basic domain of human immunodeficiency virus type 1 matrix in macrophage infection . J. Virol. . 69 . 6 . 3949–54 . 1995 . 7745752 . 10.1128/JVI.69.6.3949-3954.1995. 189124 .
• Gallay P, Swingler S, Aiken C, Trono D . HIV-1 infection of nondividing cells: C-terminal tyrosine phosphorylation of the viral matrix protein is a key regulator . Cell . 80 . 3 . 379–88 . 1995 . 7859280 . 10.1016/0092-8674(95)90488-3 . 15064293 . free .
• von Schwedler U, Kornbluth RS, Trono D . The nuclear localization signal of the matrix protein of human immunodeficiency virus type 1 allows the establishment of infection in macrophages and quiescent T lymphocytes . Proc. Natl. Acad. Sci. U.S.A. . 91 . 15 . 6992–6 . 1994 . 8041734 . 10.1073/pnas.91.15.6992 . 44324 . 1994PNAS...91.6992V . free .
• Heinzinger NK . The Vpr protein of human immunodeficiency virus type 1 influences nuclear localization of viral nucleic acids in nondividing host cells . Proc. Natl. Acad. Sci. U.S.A. . 91 . 15 . 7311–5 . 1994 . 8041786 . 10.1073/pnas.91.15.7311 . 44389 . vanc. Bukinsky MI . Haggerty SA . 3 . Ragland . AM . Kewalramani . V . Lee . MA . Gendelman . HE . Ratner . L . Stevenson . M . 1994PNAS...91.7311H . free .
• Bukrinsky MI . A nuclear localization signal within HIV-1 matrix protein that governs infection of non-dividing cells . Nature . 365 . 6447 . 666–9 . 1993 . 8105392 . 10.1038/365666a0 . vanc. Haggerty S . Dempsey MP . 3 . Sharova . Natalia . Adzhubei . Alexei . Spitz . Lynn . Lewis . Paul . Goldfarb . David . Emerman . Michael . 9524217 . 1993Natur.365..666B . 25678 .
• Dubrovsky L . Nuclear localization signal of HIV-1 as a novel target for therapeutic intervention . Mol. Med. . 1 . 2 . 217–30 . 1996 . 8529100 . 10.1007/BF03401569. 2229944 . vanc. Ulrich P . Nuovo GJ . 3 . Manogue . KR . Cerami . A . Bukrinsky . M .
• Gallay P . Role of the karyopherin pathway in human immunodeficiency virus type 1 nuclear import . J. Virol. . 70 . 2 . 1027–32 . 1996 . 8551560 . 10.1128/JVI.70.2.1027-1032.1996. 189908 . vanc. Stitt V . Mundy C . 3 . Oettinger . M . Trono . D .
• Bukrinskaya AG . Phosphorylation-dependent human immunodeficiency virus type 1 infection and nuclear targeting of viral DNA . Proc. Natl. Acad. Sci. U.S.A. . 93 . 1 . 367–71 . 1996 . 8552640 . 10.1073/pnas.93.1.367 . 40239 . vanc. Ghorpade A . Heinzinger NK . 3 . Smithgall . TE . Lewis . RE . Stevenson . M . 1996PNAS...93..367B . free .
• Sato A . Evidence for direct association of Vpr and matrix protein p17 within the HIV-1 virion . Virology . 220 . 1 . 208–12 . 1996 . 8659115 . 10.1006/viro.1996.0302 . vanc. Yoshimoto J . Isaka Y . 3 . Miki . S . Suyama . A . Adachi . A . Hayami . M . Fujiwara . T . Yoshie . O . free .
• Popov S . Critical role of reverse transcriptase in the inhibitory mechanism of CNI-H0294 on HIV-1 nuclear translocation . Proc. Natl. Acad. Sci. U.S.A. . 93 . 21 . 11859–64 . 1996 . 8876228 . 10.1073/pnas.93.21.11859 . 38149 . vanc. Dubrovsky L . Lee MA . 3 . Pennathur . S . Haffar . O . Al-Abed . Y . Tonge . P . Ulrich . P . Rexach . M . 1996PNAS...9311859P . free .
• Chen CF . The nuclear localization sequences of the BRCA1 protein interact with the importin-alpha subunit of the nuclear transport signal receptor . J. Biol. Chem. . 271 . 51 . 32863–8 . 1997 . 8955125 . 10.1074/jbc.271.51.32863 . vanc. Li S . Chen Y . 3 . Chen . PL . Sharp . ZD . Lee . WH . free .
• Freed EO, Englund G, Maldarelli F, Martin MA . Phosphorylation of residue 131 of HIV-1 matrix is not required for macrophage infection . Cell . 88 . 2 . 171–3; discussion 173–4 . 1997 . 9008157 . 10.1016/S0092-8674(00)81836-X . 14097368 . free .

Notes and References

1. Kohler M, Speck C, Christiansen M, Bischoff FR, Prehn S, Haller H, Gorlich D, Hartmann E . Evidence for Distinct Substrate Specificities of Importin α Family Members in Nuclear Protein Import . Mol Cell Biol . 19 . 11 . 7782–91 . Nov 1999 . 10523667 . 84838 . 10.1128/mcb.19.11.7782. 11858/00-001M-0000-0015-3C39-0 .
2. Web site: Entrez Gene: KPNA6 karyopherin alpha 6 (importin alpha 7).