Involved in the early to middle stages of 60S ribosomal subunit biogenesis. Part of a large pre-ribosomal ribonucleoprotein (RNP) complex, that consists of at least 62 ribosomal proteins, 45 nonribosomal proteins and both pre-rRNA and mature rRNA species. Within this complex directly interacts with TCOF1 in an RNA-independent manner. Interacts with NOP1 and NOP58 (By similarity). Belongs to the NOP5/NOP56 family.