exportin-4; exp4 (XPO4 KIAA1721)

Function

• mediates nuclear export of proteins (cargos) with broad substrate specificity
• mediates nuclear export of eIF-5A
• in the nucleus binds cooperatively to its cargo & to the GTPase Ran in its active GTP-bound form
• docking of this trimeric complex to the nuclear pore complex is mediated through binding to nucleoporins
• upon transit of a nuclear export complex into the cytoplasm, disassembling of the complex induced by RANBP1 & hydrolysis of Ran-GTP to Ran-GDP (nduced by RANGAP1 cause release of the cargo from the export receptor
• XPO4 then returns to the nuclear compartment to mediate another round of transport
• directionality of nuclear export is thought to be conferred by an asymmetric distribution of the GTP- & GDP-bound forms of Ran between the cytoplasm & nucleus
• found in a complex with XPO4, Ran & EIF5A
• found in a complex with XPO4, Ran & SMAD3
• interacts with SMAD3
• interacts with Ran & cargo proteins in a GTP-dependent manner

Structure

belongs to the exportin family

Compartment

• cytoplasm, nucleus
• shuttles between the nucleus & the cytoplasm

More general terms

• exportin
• phosphoprotein

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=64328
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:64328
• OMIM: https://mirror.omim.org/entry/611449
• UniProt: http://www.uniprot.org/uniprot/Q9C0E2.html