Component of the endoplasmic reticulum quality control (ERQC) system also called ER-associated degradation (ERAD) involved in ubiquitin-dependent degradation of misfolded endoplasmic reticulum proteins (PubMed:16289116, PubMed:28827405). Could enhance presenilin- mediated amyloid-beta protein 40 generation. Binds to ubiquilins and this interaction is required for efficient degradation of CD3D via the ERAD pathway (PubMed:18307982). {ECO:0000269|PubMed:16289116, ECO:0000269|PubMed:18307982, ECO:0000269|PubMed:28827405}. This is the function of ENSG00000051108 (HERPUD1, homocysteine inducible ER protein with ubiquitin like domain 1).