Pre-60S-associated factor involved in the cytoplasmic maturation of the 60S subunit. Involved in the dissociation and recycling of other late pre-60S factors before newly synthesized large ribosomal subunits enter translation (By similarity). Associates with nascent pre-60S particles that have not yet entered the translating pool, and is released from mature 60S subunits. Belongs to the REI1 family.