KPNB1

KPNB1
Identifiers
Aliases	KPNB1, IMB1, IPO1, IPOB, Impnb, NTF97, karyopherin subunit beta 1
External IDs	OMIM: 602738; MGI: 107532; GeneCards: KPNB1
Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 1F59, 1IBR, 1M5N, 1O6O, 1O6P, 1QGK, 1QGR, 2P8Q, 2Q5D, 2QNA, 3LWW, 3W5K
Gene location (Human) Chr. Chromosome 17 (human) Band 17q21.32 Start 47,649,476 bp End 47,685,505 bp
Gene location (Mouse) Chr. Chromosome 11 (mouse) Band 11|11 D Start 97,050,540 bp End 97,078,707 bp
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in buccal mucosa cell ventricular zone ganglionic eminence optic nerve secondary oocyte islet of Langerhans tendon of biceps brachii stromal cell of endometrium internal globus pallidus appendix Top expressed in tail of embryo condyle fossa epiblast genital tubercle primitive streak medullary collecting duct abdominal wall ureter ventricular zone More reference expression data BioGPS More reference expression data
Gene ontology Molecular function Hsp90 protein binding protein domain specific binding zinc ion binding protein binding nuclear localization sequence binding enzyme binding RNA binding importin-alpha family protein binding Cellular component nuclear membrane membrane nuclear periphery nuclear pore endoplasmic reticulum tubular network nucleoplasm extracellular exosome nucleus nuclear envelope extracellular region cytoplasm cytosol specific granule lumen ficolin-1-rich granule lumen host cell cytoplasmic stress granule protein-containing complex Biological process intracellular transport of virus apoptotic DNA fragmentation Ran protein signal transduction establishment of protein localization mitotic spindle assembly protein transport mitotic metaphase plate congression intracellular protein transport astral microtubule organization mitotic chromosome movement towards spindle pole establishment of mitotic spindle localization NLS-bearing protein import into nucleus modulation by virus of host cellular process protein import into nucleus ribosomal protein import into nucleus viral process neutrophil degranulation regulation of cholesterol biosynthetic process transport Sources:Amigo / QuickGO
Orthologs Databases NCBI: entry; OMA: entry Species Human Mouse Entrez 3837 16211 Ensembl ENSG00000108424 ENSMUSG00000001440 UniProt Q14974 P70168 RefSeq (mRNA) NM_002265 NM_001276453 NM_008379 RefSeq (protein) NP_001263382 NP_002256 NP_032405 Location (UCSC) Chr 17: 47.65 – 47.69 Mb Chr 11: 97.05 – 97.08 Mb PubMed search
Wikidata
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Importin subunit beta-1 is a protein that in humans is encoded by the KPNB1 gene.

Structure

The protein encoded by this gene is a member of the importin beta family.

An axon-localizing element within the 3′ untranslated region (UTR) of the Importin β1 transcript has been identified as necessary for its selective localization and translation in axons.

Function

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.

In neurons of the peripheral nervous system, Importin β1 has an additional role in retrograde injury signaling. Following axonal injury, Importin β1 mRNA undergoes local translation within axons, contributing to the formation of signaling complexes that are transported retrogradely to the cell body. This localized protein synthesis enables Importin β1 to participate in cytoplasmic injury-response pathways independently of its essential housekeeping functions in nucleocytoplasmic transport.

Clinical significance

Subcellular depletion of Importin β1 from axons of peripheral neurons attenuates injury-induced signaling to the cell body and delays functional recovery, demonstrating that local translation of Importin β1 is required for efficient retrograde signaling in injured neurons.

Similarly, subcellular depletion of the importin β1 3′UTR causes hippocampus-dependent memory deficits in mice, specific alteration of presynaptic long-term potentiation, and reduced local protein synthesis at mossy fiber terminals, revealing additional non-canonical roles for axonal importin β1 in presynaptic organization beyond growth and regeneration, for the establishment and long-term maintenance of neuronal circuits.

Interactions

KPNB1 has been shown to interact with:

• KPNA3,
• Karyopherin alpha 1,
• Karyopherin alpha 2,
• Mothers against decapentaplegic homolog 3,
• NUP153
• NUP50,
• NUP98,
• Nucleoporin 62,
• P53,
• Parathyroid hormone-related protein,
• RANBP1,
• RANBP2,
• Ran (biology), and
• SMN1.

Further reading

• Bukrinsky MI, Haffar OK (1997). "HIV-1 nuclear import: in search of a leader". Frontiers in Bioscience. 2 (4): d578–87. doi:10.2741/A213. PMID 9366553.
• Bukrinsky MI, Haffar OK (1998). "HIV-1 nuclear import: matrix protein is back on center stage, this time together with Vpr". Molecular Medicine. 4 (3). Cambridge, Mass.: 138–143. doi:10.1007/BF03401911. PMC 2230352. PMID 9562972.
• Christophe D, Christophe-Hobertus C, Pichon B (2000). "Nuclear targeting of proteins: how many different signals?". Cellular Signalling. 12 (5): 337–341. doi:10.1016/S0898-6568(00)00077-2. PMID 10822175.
• Chook YM, Blobel G (2001). "Karyopherins and nuclear import". Current Opinion in Structural Biology. 11 (6): 703–715. doi:10.1016/S0959-440X(01)00264-0. PMID 11751052.
• Li L, Li HS, Pauza CD, Bukrinsky M, Zhao RY (2006). "Roles of HIV-1 auxiliary proteins in viral pathogenesis and host-pathogen interactions". Cell Research. 15 (11–12): 923–934. doi:10.1038/sj.cr.7290370. PMID 16354571.
• Bukrinsky MI, Sharova N, Dempsey MP, Stanwick TL, Bukrinskaya AG, Haggerty S, et al. (1992). "Active nuclear import of human immunodeficiency virus type 1 preintegration complexes". Proceedings of the National Academy of Sciences of the United States of America. 89 (14): 6580–6584. Bibcode:1992PNAS...89.6580B. doi:10.1073/pnas.89.14.6580. PMC 49545. PMID 1631159.
• Bukrinsky MI, Haggerty S, Dempsey MP, Sharova N, Adzhubel A, Spitz L, et al. (1993). "A nuclear localization signal within HIV-1 matrix protein that governs infection of non-dividing cells". Nature. 365 (6447): 666–669. Bibcode:1993Natur.365..666B. doi:10.1038/365666a0. PMC 9524217. PMID 8105392. S2CID 25678.
• Lounsbury KM, Richards SA, Perlungher RR, Macara IG (1996). "Ran binding domains promote the interaction of Ran with p97/beta-karyopherin, linking the docking and translocation steps of nuclear import". The Journal of Biological Chemistry. 271 (5): 2357–2360. doi:10.1074/jbc.271.5.2357. PMID 8576188.
• Görlich D, Henklein P, Laskey RA, Hartmann E (1996). "A 41 amino acid motif in importin-alpha confers binding to importin-beta and hence transit into the nucleus". The EMBO Journal. 15 (8): 1810–1817. doi:10.1002/j.1460-2075.1996.tb00530.x. PMC 450097. PMID 8617226.
• Weis K, Ryder U, Lamond AI (1996). "The conserved amino-terminal domain of hSRP1 alpha is essential for nuclear protein import". The EMBO Journal. 15 (8): 1818–1825. doi:10.1002/j.1460-2075.1996.tb00531.x. PMC 450098. PMID 8617227.
• Moroianu J, Blobel G, Radu A (1996). "Nuclear protein import: Ran-GTP dissociates the karyopherin alphabeta heterodimer by displacing alpha from an overlapping binding site on beta". Proceedings of the National Academy of Sciences of the United States of America. 93 (14): 7059–7062. Bibcode:1996PNAS...93.7059M. doi:10.1073/pnas.93.14.7059. PMC 38935. PMID 8692944.
• Görlich D, Panté N, Kutay U, Aebi U, Bischoff FR (1996). "Identification of different roles for RanGDP and RanGTP in nuclear protein import". The EMBO Journal. 15 (20): 5584–5594. doi:10.1002/j.1460-2075.1996.tb00943.x. PMC 452303. PMID 8896452.
• Chi NC, Adam EJ, Adam SA (1997). "Different binding domains for Ran-GTP and Ran-GDP/RanBP1 on nuclear import factor p97". The Journal of Biological Chemistry. 272 (10): 6818–6822. doi:10.1074/jbc.272.10.6818. PMID 9045717.
• Görlich D, Dabrowski M, Bischoff FR, Kutay U, Bork P, Hartmann E, et al. (1997). "A novel class of RanGTP binding proteins". The Journal of Cell Biology. 138 (1): 65–80. doi:10.1083/jcb.138.1.65. PMC 2139951. PMID 9214382.
• Tiganis T, Flint AJ, Adam SA, Tonks NK (1997). "Association of the T-cell protein tyrosine phosphatase with nuclear import factor p97". The Journal of Biological Chemistry. 272 (34): 21548–21557. doi:10.1074/jbc.272.34.21548. PMID 9261175.