GTP-binding protein involved in nucleocytoplasmic transport. Required for the import of protein into the nucleus and also for RNA export. Not essential for cell viability. Found in a nuclear export complex with RanGTP, exportin and pre-miRNA (By similarity). GSP2 expression exhibits carbon source dependency. Present with 2460 molecules/cell in log phase SD medium. Belongs to the small GTPase superfamily. Ran family.