| Cofactor | Function | Substrates |
| Ufd1-Npl4 | ERAD, cell cycle control, nuclear transport, DNA repair, transcription, ribosome-associated degradation, essential for cell growth, clearance of damaged mitochondria | Spt23, Mga2, Sec23, Mps1, Ole1, Hmg2, CPY*, CT*, CTG*, Ste6*, Pex29, Rad52, Rpb1, Matα2, Gnd1PTC, GFHNS, Fbp1, UFD model substrates, Ci/Gli3, CD3δ, CD4, TCRα, HO-1, CDT1, SET8, tyrosinase mutant, L3MBTL1, SKP2, MHC class I heavy chains, inositol 1, 4,5-triphosphate receptors, Hmg-CoA reductase… |
| Ufd2/E4B | Ubiquitin chain synthesis, cell cycle control, ERAD, cardiac development, and nervous system maintenance | Mps1, Pex29, Ste6*, Hmg2, Spt23, Fad3, UFD model substrates, p53, p73, Ataxin-3, Fez1, myosin chaperone UNC-45 |
| Ufd3/PLAA | Ubiquitin homeostasis, ribophagy, tRNA import to mitochondria, DNA repair, multivesicular body sorting | Cse4, Rpl25, Spt23, Cps1, Vph1, Fad3, UFD model substrates, PCNA, histone H2B, N-end rule |
| Vms1/ANKZF-1 | ERAD, mitochondria stress response | Cdc13, Fzo1, CFTR, CPY* |
| Ubx1/p47/Shp1 | Autophagy, nuclear envelop formation, ER biogenesis, Golgi assembly | GFP-Osh1, Fad3, UFD model substrates, NEMO, Rum1 |
| Ubx2 | ERAD, lipid droplet maintenance | Hmg2, CPY*, KSS, Ubc6*, Sec61-2, Deg1-GFP, Spt23, SREBP, RNA binding protein HuR, Insig-1, ApoB-100, UBC6-B5 mutant |
| Ubx3 | Unknown | Unknown |
| Ubx4 | ERAD, DNA repair | CPY*, Ste6*, Fbp1, Rpb1 |
| Ubx5 | Links Cdc48 to CRL E3 ligases | Rpb1, HIF1α |
| Ubx6 | Unknown | Unknown |
| Ubx7 | Unknown, in complex with Dfm1 | Unknown |
| FAF1 | ERAD, proapoptosis factor | CD3δ, Hsp70, β-catenin |
| Ataxin-3 | Ubiquitin chain editing, ERAD, stress response | TCRα, BACE mutant, SOD1, PARKIN, CHIP, integrin subunits, UFD model substrates |
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