In association with GSP1, required for nuclear export of both pre-40S and pre-60S ribosomal subunits. Required for the late maturation of the 18S and 5.8S rRNA of the pre-40S ribosomes and for maturation of the 25S and 5.8S rRNA of the pre-60S ribosomes. Interacts with GSP1. Present with 8170 molecules/cell in log phase SD medium. Belongs to the RRP12 family.