Fig. 2.

Roles of UBQLN2 in protein degradation in both the UPS and the autophagy systems. a UBQLN2 targets ubiquitinated substrates and interacts with ER proteins involved in endoplasmic-reticulum-associated protein degradation (ERAD), such as Herp and Ubxd8, to drive substrates degradation by the 26S proteasome. b UBQLN2 is also implicated in the macroautophagy and interacts with LC3 indirectly through an unknown mechanism and can deliver ubiquitinated proteins bound to the ubiquitin-associated domain (UBA). UBQLN2: Ubiquilin-2; Ub: Ubiquitin; LC3: Microtubule-associated protein 1 light chain 3, Herp: Homocysteine-induced endoplasmic reticulum protein, isoform A. Ubxd8: ubiquitin regulatory X domain-containing protein 8