Promotes efficient arsenite-induced clearance of stress granules (SGs) (PubMed:29804830). May have a role in the ubiquitin-proteasome system (UPS) protecting cells from metalloid-induced proteotoxicity (PubMed:24121501, PubMed:24297164). Interacts (via its ubiquitin-like domain) with CDC48 (via N-terminus). Associates with the 26S proteasome. Specifically interacts with the regulatory particle (RP) subunit RPN2. Exposure to arsenite, a known inducer of protein misfolding resulting in accumulation of polyubiquitinated conjugates, enhances the association with the proteoasome. Binds to ubiquitinated proteins conjugated to a 4 or more molecule ubiquitin chain. Binding to ubiquitinated proteins is zinc-dependent. By transcriptional activator RPN4. Present with 4280 molecules/cell in log phase SD medium.