ASCC2 is a ubiquitin-binding protein that functions as a critical component of the ASCC complex, with dual roles in DNA repair and ribosome quality control. In DNA repair, ASCC2 recognizes K63-linked polyubiquitin chains through its CUE domain and recruits the ASCC complex to sites of alkylation damage, specifically binding polyubiquitinated PCNA at stalled replication forks 12. This recruitment is essential for proper alkylation adduct repair kinetics; cells lacking functional ASCC2 show increased sensitivity to alkylating agents 1. In the ribosome quality control pathway, ASCC2 forms the human RQT complex alongside ASCC3 and TRIP4 34. Here, ASCC2 recognizes K63-linked polyubiquitin chains on ribosomal uS10 protein that are deposited by ZNF598 during ribosomal collision, promoting recruitment of the RQT complex and enabling ASCC3-mediated disassembly of stalled ribosomes 4. The ubiquitin-binding and ATPase activities of ASCC2 and ASCC3 are both crucial for triggering ribosome quality control 3. Additionally, ASCC2 participates in transcriptional regulation as part of the ASC-1 complex 5. Cancer-associated mutations in ASCC2 reduce its interaction affinity with ASCC3, potentially compromising both DNA repair and quality control functions 6.