ER-Phagy, ER Homeostasis, and ER Quality Control: Implications for Disease

Lysosomal degradation of endoplasmic reticulum (ER) fragments by autophagy, termed ER-phagy or reticulophagy, occurs under normal as well as stress conditions. The recent discovery of multiple ER-phagy receptors has stimulated studies on the roles of ER-phagy. We discuss how the ER-phagy receptors and the cellular components that work with these receptors mediate two important functions: ER homeostasis and ER quality control. We highlight that ER-phagy plays an important role in alleviating ER expansion induced by ER stress, and acts as an alternative disposal pathway for misfolded proteins. We suggest that the latter function explains the emerging connection between ER-phagy and disease. Additional ER-phagy-associated functions and important unanswered questions are also discussed.

Automated summary

ER-phagy, the process of lysosomal degradation of endoplasmic reticulum fragments by autophagy, occurs under normal and stress conditions. The discovery of multiple ER-phagy receptors has led to studies on the functions of ER-phagy receptors and their role in maintaining ER homeostasis and quality control. ER-phagy plays a crucial role in alleviating ER expansion induced by ER stress and acts as an alternative disposal pathway for misfolded proteins, which may explain the connection between ER-phagy and disease.