Ubiquilin-2 (UBQLN2)

Plays an essential role in the regulation of different protein degradation mechanisms and pathways such as ubiquitin- proteasome system (UPS), autophagy and the endoplasmic reticulum- associated protein degradation (ERAD) pathway. Mediates the proteasomal targeting of misfolded or accumulated proteins for degradation by binding (through UBA domain) to their polyubiquitin chains and by interacting (through ubiquitin-like domain) with the subunits of the proteasome (PubMed:10983987).

Plays a role in the ERAD pathway through its interaction with ER-localized proteins FAF2/UBXD8 and HERPUD1 and might form a link between the polyubiquitinated ERAD substrates and the proteasome (PubMed:24215460, PubMed:18307982). Involved in the regulation of macroautophagy and autophagosome formation; required for maturation of autophagy-related protein LC3 from the cytosolic form LC3-I into the membrane-bound form LC3-II and might aid in the maturation of autophagosomes to autolysosomes by mediating autophagosome-lysosome fusion (PubMed:19148225, PubMed:20529957).