Probable metalloprotease 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 REI1. Present with 45100 molecules/cell in log phase SD medium. Belongs to the peptidase M24 family.