Export receptor for importin alpha (SRP1). Mediates importin-alpha re-export from the nucleus to the cytoplasm after import substrates have been released into the nucleoplasm. Binds with high affinity to SRP1 only in the presence of RanGTP. The complex is dissociated by the RanGTP-binding protein YRB1. Present with 23500 molecules/cell in log phase SD medium. Belongs to the XPO2/CSE1 family.