AMPK Negatively Regulates Mitophagy in the Heart

Maintaining mitochondrial homeostasis and energy metabolism is essential for normal cardiac function. Adenosine-monophosphate activated protein kinase (AMPK) is an energy sensor in the cell that detects and reacts to fluctuations in intracellular AMP: ATP ratio and it is activated by increased AMP levels. Activated AMPK promotes ATP production by inhibiting anabolic consuming pathways and enhancing catabolic pathways. AMPK has been shown to protect the heart under several cardiac conditions including ischemia and starvation. The cardioprotective effects have been attributed partially to its ability to induce autophagy, a cellular degradation pathway that eliminates protein aggregates and damaged organelles through the lysosome. When mitochondria are targeted for degradation through autophagy, it is termed mitophagy. Both autophagy and mitophagy may occur under the same conditions but they do not always go in the same direction, suggesting that they may be regulated by distinct pathways. Despite its abilit...