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 like ARX1, TIF6 and ALB1 before newly synthesized large ribosomal subunits enter translation. Cooperates with the co-chaperone JJJ1 in the release of the nuclear-export factor ARX1. May act redundantly with REH1 to directly promote a stabilizing structural rearrangement in cytoplasmic 60S subunit maturation independent on ARX1 recycling. Associates with nascent pre-60S particles that have not yet entered the translating pool, and is released from mature 60S subunits. Interacts with pre-60S factors ARX1 and RPL24. Interacts with JJJ1. Present with 830 molecules/cell in log phase SD medium. Belongs to the REI1 family.