SPRTN is a DNA-dependent metalloendopeptidase that proteolytically cleaves DNA-protein crosslinks (DPCs), highly toxic lesions induced by UV light, formaldehyde, and endogenous factors 12. During DNA synthesis, SPRTN associates with replication machinery to remove DPCs that would otherwise block replication and transcription 13. SPRTN acts as a pleiotropic protease targeting multiple DNA-binding proteins including TOP1, TOP2A, and histones H3/H4 3. Its activity is allosterically activated by ubiquitin binding to the protease domain, ensuring substrate specificity and preventing off-target cleavage 4. SPRTN catalyzes proteolytic cleavage of HMCES crosslinks following BRIP1/FANCJ helicase unwinding and recruits VCP/p97 to damage sites 56. Additionally, SPRTN promotes CHEK1 activation during normal replication through proteolytic cleavage 7. Biallelic SPRTN mutations cause Ruijs-Aalfs syndrome, characterized by progeria and hepatocellular carcinoma, with pathology driven by unresolved DPCs activating cGAS-STING innate immunity 89. SPRTN deficiency results in genome instability, chromosome 1 errors, and premature aging, highlighting its essential role in maintaining genomic integrity.