NOP56 encodes a highly conserved nucleolar protein that serves as a core component of box C/D small nucleolar ribonucleoprotein (snoRNP) complexes, functioning primarily in ribosomal RNA processing and modification 1. The protein is essential for early to middle stages of 60S ribosomal subunit biogenesis and is required for the biogenesis of box C/D snoRNAs including U3, U8, and U14 1. NOP56 participates in the small subunit processome assembly in the nucleolus, where it works with other factors to facilitate RNA folding, modifications, and cleavage of pre-ribosomal RNA 1. The protein enhances rRNA 2'-O methylation through direct interaction with fibrillarin (FBL), strengthening the FBL-NOP56 interaction and facilitating box C/D snoRNP complex assembly 1. Disease relevance centers on spinocerebellar ataxia type 36 (SCA36), caused by intronic GGCCTG hexanucleotide repeat expansions in NOP56 that undergo repeat-associated non-AUG (RAN) translation, producing toxic poly(Gly-Pro) and poly(Pro-Arg) peptides 23. Loss-of-function studies in zebrafish demonstrate severe neurodegenerative phenotypes including cerebellar absence and CNS apoptosis 4. NOP56 also shows dysregulated expression in various cancers, suggesting potential tumor biomarker applications 56.