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Protein KPNB1 PDB 1f59.png
Available structures
PDBOrtholog search: PDBe RCSB
AliasesKPNB1, IMB1, IPO1, IPOB, Impnb, NTF97, karyopherin subunit beta 1
External IDsOMIM: 602738 MGI: 107532 HomoloGene: 1707 GeneCards: KPNB1
Gene location (Human)
Chromosome 17 (human)
Chr.Chromosome 17 (human)[1]
Chromosome 17 (human)
Genomic location for KPNB1
Genomic location for KPNB1
Band17q21.32Start47,649,476 bp[1]
End47,685,505 bp[1]
RNA expression pattern
PBB GE KPNB1 208975 s at fs.png

PBB GE KPNB1 208974 x at fs.png

PBB GE KPNB1 213803 at fs.png
More reference expression data
RefSeq (mRNA)



RefSeq (protein)



Location (UCSC)Chr 17: 47.65 – 47.69 MbChr 11: 97.16 – 97.19 Mb
PubMed search[3][4]
View/Edit HumanView/Edit Mouse

Importin subunit beta-1 is a protein that in humans is encoded by the KPNB1 gene.[5][6]


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 classical nuclear localization signal (NLS) requires the NLS import receptor, a heterodimer of importin alpha and beta subunits. Each of these subunits are part of the karyopherin family of proteins. 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. Interactions between importin beta and the FG repeats of nucleoporins are essential in translocation through the pore complex. The protein encoded by this gene is a member of the importin beta family.[7]


KPNB1 has been shown to interact with:


  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000108424 - Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000001440 - Ensembl, May 2017
  3. ^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. ^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. ^ Chi NC, Adam EJ, Adam SA (August 1995). "Sequence and characterization of cytoplasmic nuclear protein import factor p97". J. Cell Biol. 130 (2): 265–74. doi:10.1083/jcb.130.2.265. PMC 2199936. PMID 7615630.
  6. ^ Görlich D, Kostka S, Kraft R, Dingwall C, Laskey RA, Hartmann E, Prehn S (September 1995). "Two different subunits of importin cooperate to recognize nuclear localization signals and bind them to the nuclear envelope". Curr. Biol. 5 (4): 383–92. doi:10.1016/S0960-9822(95)00079-0. PMID 7627554.
  7. ^ "Entrez Gene: KPNB1 karyopherin (importin) beta 1".
  8. ^ a b c Köhler M, Speck C, Christiansen M, Bischoff FR, Prehn S, Haller H, Görlich D, Hartmann E (November 1999). "Evidence for distinct substrate specificities of importin alpha family members in nuclear protein import". Mol. Cell. Biol. 19 (11): 7782–91. doi:10.1128/mcb.19.11.7782. PMC 84838. PMID 10523667.
  9. ^ Nachury MV, Ryder UW, Lamond AI, Weis K (January 1998). "Cloning and characterization of hSRP1 gamma, a tissue-specific nuclear transport factor". Proc. Natl. Acad. Sci. U.S.A. 95 (2): 582–7. doi:10.1073/pnas.95.2.582. PMC 18463. PMID 9435235.
  10. ^ a b c Percipalle P, Clarkson WD, Kent HM, Rhodes D, Stewart M (March 1997). "Molecular interactions between the importin alpha/beta heterodimer and proteins involved in vertebrate nuclear protein import". J. Mol. Biol. 266 (4): 722–32. doi:10.1006/jmbi.1996.0801. PMID 9102465.
  11. ^ Nagoshi E, Yoneda Y (April 2001). "Dimerization of sterol regulatory element-binding protein 2 via the helix-loop-helix-leucine zipper domain is a prerequisite for its nuclear localization mediated by importin beta". Mol. Cell. Biol. 21 (8): 2779–89. doi:10.1128/MCB.21.8.2779-2789.2001. PMC 86908. PMID 11283257.
  12. ^ Ullman KS, Powers MA, Forbes DJ (September 1997). "Nuclear export receptors: from importin to exportin". Cell. 90 (6): 967–70. doi:10.1016/s0092-8674(00)80361-x. PMID 9323123.
  13. ^ Xiao Z, Liu X, Lodish HF (August 2000). "Importin beta mediates nuclear translocation of Smad 3". J. Biol. Chem. 275 (31): 23425–8. doi:10.1074/jbc.C000345200. PMID 10846168.
  14. ^ a b c Ben-Efraim I, Gerace L (January 2001). "Gradient of increasing affinity of importin beta for nucleoporins along the pathway of nuclear import". J. Cell Biol. 152 (2): 411–7. doi:10.1083/jcb.152.2.411. PMC 2199621. PMID 11266456.
  15. ^ Nakielny S, Shaikh S, Burke B, Dreyfuss G (April 1999). "Nup153 is an M9-containing mobile nucleoporin with a novel Ran-binding domain". EMBO J. 18 (7): 1982–95. doi:10.1093/emboj/18.7.1982. PMC 1171283. PMID 10202161.
  16. ^ Kehlenbach RH, Gerace L (June 2000). "Phosphorylation of the nuclear transport machinery down-regulates nuclear protein import in vitro". J. Biol. Chem. 275 (23): 17848–56. doi:10.1074/jbc.M001455200. PMID 10749866.
  17. ^ Lindsay ME, Plafker K, Smith AE, Clurman BE, Macara IG (August 2002). "Npap60/Nup50 is a tri-stable switch that stimulates importin-alpha:beta-mediated nuclear protein import". Cell. 110 (3): 349–60. doi:10.1016/s0092-8674(02)00836-x. PMID 12176322.
  18. ^ Moroianu J, Blobel G, Radu A (September 1997). "RanGTP-mediated nuclear export of karyopherin alpha involves its interaction with the nucleoporin Nup153". Proc. Natl. Acad. Sci. U.S.A. 94 (18): 9699–704. doi:10.1073/pnas.94.18.9699. PMC 23253. PMID 9275187.
  19. ^ Bonifaci N, Moroianu J, Radu A, Blobel G (May 1997). "Karyopherin beta2 mediates nuclear import of a mRNA binding protein". Proc. Natl. Acad. Sci. U.S.A. 94 (10): 5055–60. doi:10.1073/pnas.94.10.5055. PMC 24630. PMID 9144189.
  20. ^ Akakura S, Yoshida M, Yoneda Y, Horinouchi S (May 2001). "A role for Hsc70 in regulating nucleocytoplasmic transport of a temperature-sensitive p53 (p53Val-135)". J. Biol. Chem. 276 (18): 14649–57. doi:10.1074/jbc.M100200200. PMID 11297531.
  21. ^ Cingolani G, Bednenko J, Gillespie MT, Gerace L (December 2002). "Molecular basis for the recognition of a nonclassical nuclear localization signal by importin beta". Mol. Cell. 10 (6): 1345–53. doi:10.1016/s1097-2765(02)00727-x. PMID 12504010.
  22. ^ Lam MH, Hu W, Xiao CY, Gillespie MT, Jans DA (March 2001). "Molecular dissection of the importin beta1-recognized nuclear targeting signal of parathyroid hormone-related protein". Biochem. Biophys. Res. Commun. 282 (2): 629–34. doi:10.1006/bbrc.2001.4607. PMID 11401507.
  23. ^ a b Yaseen NR, Blobel G (September 1999). "GTP hydrolysis links initiation and termination of nuclear import on the nucleoporin nup358". J. Biol. Chem. 274 (37): 26493–502. doi:10.1074/jbc.274.37.26493. PMID 10473610.
  24. ^ a b Plafker K, Macara IG (May 2000). "Facilitated nucleocytoplasmic shuttling of the Ran binding protein RanBP1". Mol. Cell. Biol. 20 (10): 3510–21. doi:10.1128/mcb.20.10.3510-3521.2000. PMC 85643. PMID 10779340.
  25. ^ Delphin C, Guan T, Melchior F, Gerace L (December 1997). "RanGTP targets p97 to RanBP2, a filamentous protein localized at the cytoplasmic periphery of the nuclear pore complex". Mol. Biol. Cell. 8 (12): 2379–90. doi:10.1091/mbc.8.12.2379. PMC 25714. PMID 9398662.
  26. ^ Kutay U, Izaurralde E, Bischoff FR, Mattaj IW, Görlich D (March 1997). "Dominant-negative mutants of importin-beta block multiple pathways of import and export through the nuclear pore complex". EMBO J. 16 (6): 1153–63. doi:10.1093/emboj/16.6.1153. PMC 1169714. PMID 9135132.
  27. ^ Narayanan U, Ospina JK, Frey MR, Hebert MD, Matera AG (July 2002). "SMN, the spinal muscular atrophy protein, forms a pre-import snRNP complex with snurportin1 and importin beta". Hum. Mol. Genet. 11 (15): 1785–95. doi:10.1093/hmg/11.15.1785. PMC 1630493. PMID 12095920.

Further reading[edit]