IPO5

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
Aliases	IPO5, IMB3, KPNB3, Pse1, RANBP5, imp5, importin 5
External IDs	OMIM: 602008; MGI: 1917822; HomoloGene: 1710; GeneCards: IPO5; OMA:IPO5 - orthologs
Gene location (Human) Chr. Chromosome 13 (human)[1] Band 13q32.2 Start 97,953,658 bp[1] End 98,024,296 bp[1]
Gene location (Mouse) Chr. Chromosome 14 (mouse)[2] Band 14|14 E4- E5 Start 121,148,636 bp[2] End 121,185,411 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in sperm left testis right testis ventricular zone embryo cartilage tissue ganglionic eminence body of pancreas gastrocnemius muscle stromal cell of endometrium Top expressed in seminiferous tubule primitive streak epiblast somite lens tail of embryo spermatid medullary collecting duct ventricular zone mandibular prominence More reference expression data BioGPS More reference expression data
Gene ontology Molecular function GTPase inhibitor activity protein binding nuclear localization sequence binding RNA binding nuclear import signal receptor activity Cellular component membrane nuclear periphery nuclear pore nucleolus nucleus nuclear membrane cytoplasm Biological process ribosomal protein import into nucleus cellular response to amino acid stimulus protein transport positive regulation of protein import into nucleus viral process intracellular protein transport negative regulation of GTPase activity NLS-bearing protein import into nucleus transport protein import into nucleus negative regulation of cyclin-dependent protein serine/threonine kinase activity Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 3843 70572 Ensembl ENSG00000065150 ENSMUSG00000030662 UniProt O00410 Q8BKC5 RefSeq (mRNA) NM_002271 NM_023579 NM_001360602 RefSeq (protein) NP_002262 NP_076068 NP_001347531 Location (UCSC) Chr 13: 97.95 – 98.02 Mb Chr 14: 121.15 – 121.19 Mb PubMed search [3] [4]
Wikidata
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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.^[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]