IPO5

Importin 5
Identifiers
Symbols IPO5 ; IMB3; KPNB3; Pse1; RANBP5; imp5
External IDs OMIM: 602008 MGI: 1917822 HomoloGene: 1710 GeneCards: IPO5 Gene
RNA expression pattern
More reference expression data
Orthologs
Species Human Mouse
Entrez 3843 70572
Ensembl ENSG00000065150 ENSMUSG00000030662
UniProt O00410 Q8BKC5
RefSeq (mRNA) NM_002271 NM_023579
RefSeq (protein) NP_002262 NP_076068
Location (UCSC) Chr 13:
97.95 – 98.02 Mb
Chr 14:
120.91 – 120.95 Mb
PubMed search

Importin-5 is a protein that in humans is encoded by the IPO5 gene.[1][2][3] The protein encoded by this gene is a member of the importin beta family.

Function

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.[4]

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.[5]

References

  1. Yaseen NR, Blobel G (May 1997). "Cloning and characterization of human karyopherin beta3". Proc Natl Acad Sci U S A 94 (9): 4451–6. doi:10.1073/pnas.94.9.4451. PMC 20743. PMID 9114010.
  2. Deane R, Schäfer W, Zimmermann HP, Mueller L, Görlich D, Prehn S, Ponstingl H, Bischoff FR (Sep 1997). "Ran-binding protein 5 (RanBP5) is related to the nuclear transport factor importin-beta but interacts differently with RanBP1". Mol Cell Biol 17 (9): 5087–96. PMC 232359. PMID 9271386.
  3. Deng T, Engelhardt OG, Thomas B, Akoulitchev AV, Brownlee GG, Fodor E (Nov 2006). "Role of ran binding protein 5 in nuclear import and assembly of the influenza virus RNA polymerase complex". J Virol 80 (24): 11911–9. doi:10.1128/JVI.01565-06. PMC 1676300. PMID 17005651.
  4. "Entrez Gene: RANBP5 RAN binding protein 5".
  5. 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 Res. 40 (17): 8484–98. doi:10.1093/nar/gks598. PMC 3458550. PMID 22730302.

Further reading


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