Importin-5 is a protein that in humans is encoded by the IPO5 gene.[5][6][7] The protein encoded by this gene is a member of the importin beta family. Structurally, the protein adopts the shape of a right hand solenoid and is composed of 24 HEAT repeats.[8]

IPO5
Identifiers
AliasesIPO5, IMB3, KPNB3, Pse1, RANBP5, imp5, importin 5
External IDsOMIM: 602008; MGI: 1917822; HomoloGene: 1710; GeneCards: IPO5; OMA:IPO5 - orthologs
Orthologs
SpeciesHumanMouse
Entrez
Ensembl
UniProt
RefSeq (mRNA)

NM_002271

NM_023579
NM_001360602

RefSeq (protein)

NP_002262

NP_076068
NP_001347531

Location (UCSC)Chr 13: 97.95 – 98.02 MbChr 14: 121.15 – 121.19 Mb
PubMed search[3][4]
Wikidata
View/Edit HumanView/Edit Mouse

Function

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Nuclear 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. Interactions between importin beta and the FG repeats of nucleoporins are essential in translocation through the pore complex.[9]

IPO5 facilitates cytoplasmic polyadenylation element-binding protein (CPEB)3 translocation by binding to RRM1 motif of CPEB3 in neurons. NMDAR signaling increases RanBP1 expression and reduces the level of cytoplasmic GTP-bound Ran. These changes enhance CPEB3–IPO5 interaction, which consequently accelerates the nuclear import of CPEB3 and promotes its nuclear function.[10]

References

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  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000065150Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000030662Ensembl, 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. ^ Yaseen NR, Blobel G (April 1997). "Cloning and characterization of human karyopherin beta3". Proceedings of the National Academy of Sciences of the United States of America. 94 (9): 4451–6. Bibcode:1997PNAS...94.4451Y. doi:10.1073/pnas.94.9.4451. PMC 20743. PMID 9114010.
  6. ^ Deane R, Schäfer W, Zimmermann HP, Mueller L, Görlich D, Prehn S, et al. (September 1997). "Ran-binding protein 5 (RanBP5) is related to the nuclear transport factor importin-beta but interacts differently with RanBP1". Molecular and Cellular Biology. 17 (9): 5087–96. doi:10.1128/mcb.17.9.5087. PMC 232359. PMID 9271386.
  7. ^ Deng T, Engelhardt OG, Thomas B, Akoulitchev AV, Brownlee GG, Fodor E (December 2006). "Role of ran binding protein 5 in nuclear import and assembly of the influenza virus RNA polymerase complex". Journal of Virology. 80 (24): 11911–9. doi:10.1128/JVI.01565-06. PMC 1676300. PMID 17005651.
  8. ^ Swale C, Da Costa B, Sedano L, Garzoni F, McCarthy AA, Berger I, et al. (May 2020). "X-ray Structure of the Human Karyopherin RanBP5, an Essential Factor for Influenza Polymerase Nuclear Trafficking" (PDF). Journal of Molecular Biology. 432 (10): 3353–3359. doi:10.1016/j.jmb.2020.03.021. PMID 32222384. S2CID 219670671.
  9. ^ "Entrez Gene: RANBP5 RAN binding protein 5".
  10. ^ Chao HW, Lai YT, Lu YL, Lin CL, Mai W, Huang YS (September 2012). "NMDAR signaling facilitates the IPO5-mediated nuclear import of CPEB3". Nucleic Acids Research. 40 (17): 8484–98. doi:10.1093/nar/gks598. PMC 3458550. PMID 22730302.

Further reading

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