UBA52 is a ubiquitin-ribosomal protein fusion that functions as a component of the 60S ribosomal subunit, specifically serving as ribosomal protein L40 12345. The protein operates through a dual mechanism: it supplies both ubiquitin and RPL40 simultaneously to ribosomes, with cleavage of RPL40 from the fusion protein being essential for maintaining protein synthesis and cell-cycle progression 6. UBA52 is particularly important for cap-dependent translation of specific mRNAs, including vesicular stomatitis virus transcripts 12. Beyond translation, UBA52 participates in critical cellular processes including ubiquitin homeostasis maintenance, where it works with USP7 deubiquitinase and MLKL to support autophagy and prevent neurodegeneration 7. UBA52 also regulates DNA repair by antagonizing RNF168-mediated histone ubiquitination at damage sites 8. Disease relevance includes roles in gastric cancer progression through SMYD5-mediated methylation affecting translation output 4, pulmonary fibrosis pathogenesis 9, cholangiocarcinoma drug resistance via the ROCK2/UBA52/DRP1 axis 10, diabetic nephropathy through glucose-responsive promoter activation in renal tubules 11, and ulcerative colitis via interaction with selenoprotein S and macrophage polarization 12. Clinically, UBA52 dysregulation represents a potential therapeutic target across multiple cancers and neurodegenerative diseases.