exportin-2; exp2; importin-alpha re-exporter; chromosome segregation 1-like protein; cellular apoptosis susceptibility protein (CSE1L, CAS, XPO2)

Function

• export receptor for importin-alpha
• mediates importin-alpha re-export from the nucleus to the cytoplasm after import substrates (cargos) have been released into the nucleoplasm
• in the nucleus, binds cooperatively to importin-alpha & 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 & hydrolysis of Ran-GTP to Ran-GDP (induced by RANBP1 & RANGAP1, respectively) causes release of the importin-alpha from the export receptor CSE1L/XPO2, then return to the nuclear compartment to mediate another round of transport
• the 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 CSE1L/XPO2, Ran & KPNA2
• binds with high affinity to importin-alpha only in the presence of RanGTP
• the complex is dissociated by the combined action of RanBP1 & RanGAP1

Structure

• belongs to the XPO2/CSE1 family
• contains 1 importin N-terminal domain

Compartment

• cytoplasm. nucleus
• shuttles between the nucleus & the cytoplasm

Alternative splicing

named isoforms=3

Expression

• highly expressed in proliferating cells

More general terms

• exportin

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=1434
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:1434
• OMIM: https://mirror.omim.org/entry/601342
• UniProt: http://www.uniprot.org/uniprot/P55060.html