Importin subunit alpha-6 explained

Importin subunit alpha-6 is a protein that in humans is encoded by the KPNA5 gene.^[1]

The transport of molecules between the nucleus and the cytoplasm in eukaryotic cells is mediated by the nuclear pore complex (NPC) which consists of 60-100 proteins and is probably 120 million daltons in molecular size. Small molecules (up to 70 kD) can pass through the nuclear pore by nonselective diffusion; larger molecules are transported by an active process. Most nuclear proteins contain short basic amino acid sequences known as nuclear localization signals (NLSs).

KPNA5 protein belongs to the importin alpha protein family and is thought to be involved in NLS-dependent protein import into the nucleus^[2]

Further reading

• Bukrinsky MI, Haffar OK . HIV-1 nuclear import: in search of a leader. . Front. Biosci. . 2 . 4. d578–87 . 2004 . 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 .
• Bukrinsky MI, Sharova N, Dempsey MP, etal . 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 . 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, Choe S, Ebright M, etal . 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 . 10.1128/JVI.69.12.7909-7916.1995. 189735 .
• Adams MD, Kerlavage AR, Fleischmann RD, etal . Initial assessment of human gene diversity and expression patterns based upon 83 million nucleotides of cDNA sequence. . Nature . 377 . 6547 Suppl . 3–174 . 1995 . 7566098 . .
• Gallay P, Swingler S, Song J, etal . 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 . 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, Bukinsky MI, Haggerty SA, etal . 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 . 1994PNAS...91.7311H . free .
• Bukrinsky MI, Haggerty S, Dempsey MP, etal . 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 . 9524217 . 1993Natur.365..666B . 25678 .
• Dubrovsky L, Ulrich P, Nuovo GJ, etal . 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 .
• Gallay P, Stitt V, Mundy C, etal . 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 .
• Bukrinskaya AG, Ghorpade A, Heinzinger NK, etal . 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 . 1996PNAS...93..367B . free .
• Sato A, Yoshimoto J, Isaka Y, etal . 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 . free .
• Popov S, Dubrovsky L, Lee MA, etal . 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 . 1996PNAS...9311859P . 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 .
• Gallay P, Hope T, Chin D, Trono D . HIV-1 infection of nondividing cells through the recognition of integrase by the importin/karyopherin pathway. . Proc. Natl. Acad. Sci. U.S.A. . 94 . 18 . 9825–30 . 1997 . 9275210 . 10.1073/pnas.94.18.9825 . 23276 . 1997PNAS...94.9825G . free .
• Besançon F, Just J, Bourgeade MF, etal . HIV-1 p17 and IFN-gamma both induce fructose 1,6-bisphosphatase. . J. Interferon Cytokine Res. . 17 . 8 . 461–7 . 1997 . 9282826 . 10.1089/jir.1997.17.461 .

Notes and References

1. Kohler M, Ansieau S, Prehn S, Leutz A, Haller H, Hartmann E . Cloning of two novel human importin-alpha subunits and analysis of the expression pattern of the importin-alpha protein family . FEBS Lett . 417 . 1 . 104–8 . Jan 1998 . 9395085 . 10.1016/S0014-5793(97)01265-9 . 84237136 . free .
2. Web site: Entrez Gene: KPNA5 karyopherin alpha 5 (importin alpha 6).