With ARX1, involved in proper assembly of pre-ribosomal particles during the biogenesis of the 60S ribosomal subunit. Accompanies the pre-60S particles to the cytoplasm. Component of the nucleoplasmic and cytoplasmic pre-60S ribosomal particles. Interacts directly with ARX1. Present with 4780 molecules/cell in log phase SD medium. Belongs to the ALB1 family.