Plays a role in DNA damage repair as component of the ASCC complex. Recruits ASCC3 and ALKBH3 to sites of DNA damage by binding to polyubiquitinated proteins that have 'Lys-63'-linked polyubiquitin chains (PubMed:29144457). Part of the ASC-1 complex that enhances NF-kappa-B, SRF and AP1 transactivation (PubMed:12077347). Involved in activation of the ribosome quality control (RQC) pathway, a pathway that degrades nascent peptide chains during problematic translation (PubMed:32099016). As part of the ribosome quality control trigger (RQT) complex, recognizes ZNF598-dependent ubiquitination of stalled ribosomes (By similarity). Identified in the ASCC complex that contains ASCC1, ASCC2 and ASCC3 (PubMed:29144457, PubMed:29997253). Interacts directly with ASCC3 (PubMed:29997253, PubMed:32099016). The ASCC complex interacts with ALKBH3 (PubMed:29144457, PubMed:22055184). Interacts (via CUE domain) with 'Lys-63'-linked polyubiquitin chains, but not with 'Lys-48'-linked polyubiquitin chains (PubMed:29144457). Part of the ASC-1 complex, that contains TRIP4, ASCC1, ASCC2 and ASCC3 (PubMed:12077347). Component of the RQT (ribosome quality control trigger) complex, that contains ASCC2, ASCC3 and TRIP4 (PubMed:32099016). Interacts with TRIP4 (PubMed:32099016). Interacts with CSRP1 (PubMed:26924529). Interacts with PRPF8, a component of the spliceosome (PubMed:29144457). Interacts with ZCCHC4 (PubMed:31799605). Colocalizes with the spliceosomal components PRPF8 and SNRNP200/BRR2 in nuclear foci when cells have been exposed to alkylating agents that cause DNA damage. Colocalizes with RNF113A and 'Lys-63'-linked polyubiquitinated proteins, ALKBH3 and ASCC3 in nuclear foci when cells have been exposed to alkylating agents that cause DNA damage. Ubiquitous. Belongs to the ASCC2 family.