Autophagy and Energy Metabolism.

Autophagy is a lysosome-dependent catabolic process. Both extra- and intra-cellular components are engulfed in autophagic vacuoles and degraded to simple molecules, such as monosaccharides, fatty acids and amino acids. Then, these molecules can be further used to produce ATP through catabolic reactions and/or provide building blocks for the synthesis of essential proteins. Therefore, we consider autophagy a critical and fine-tuned process in maintaining energy homeostasis. The complicated relationships between autophagy and energy metabolism have raised broad interest and have been extensively studied. In this chapter, we summarize the relationships enabling autophagy to control or modulate energy metabolism and allowing metabolic pathways to regulate autophagy. Specifically, we review the correlations between autophagy and energy homeostasis in terms of oxidative phosphorylation, reactive oxygen species in mitochondria, glycolysis, metabolism of glycogen and protein, and so on. An understanding of the role of autophagy in energy homeostasis could help us better appreciate how autophagy determines cell fate under stressful conditions or pathological processes.