Proteasome-associated ubiquitin receptor; K48-specific Ub chain binding protein that recruits substrates to the proteasome; nuclear excision repair factor 2 (NER2) subunit that binds damaged DNA during NER, linking repair to proteolysis; NER2 binds DDR gene promoters repressing transcription in the absence of damage; stimulates Png1p-induced protein deglycosylation; ubiquilin that contains a Ub-like (UBL) and two Ub-associated (UBA) domains; UBA2 protects Rad23p from proteasomal degradation