Autophagy in health and disease. 4. The role of pancreatic beta-cell autophagy in health and diabetes.

Autophagy is an evolutionarily conserved machinery for degradation and recycling of various cytoplasmic components such as long-lived proteins and organelles. In pancreatic beta-cells, as in most other cells, autophagy is also important for the low basal turnover of ubiquitinated proteins and damaged organelles under normal conditions. Insulin resistance results in upregulation of autophagic activity in beta-cells. Induced autophagy in beta-cells plays a pivotal role in the adaptive expansion of beta-cell mass. Nevertheless, it is not clear whether autophagy is protective or detrimental in response to cellular stresses in beta-cells. In this review, we describe the crucial roles of autophagy in normal function of beta-cells and discuss how dysfunction of the autophagic machinery could lead to the development of diabetes mellitus.