Intracellular signaling of the AMP-activated protein kinase.

AMP-activated protein kinase (AMPK) is an essential cellular energy sensor that senses the cellular energy status and maintains cellular energy balance. The AMPK coordinates cellular and whole-body energy homeostasis through stimulating catabolic ATP-producing and suppressing anabolic ATP-consuming intracellular signaling pathways. AMPK induces autophagy and inhibits cell growth in response to starvation, a process that involves regulating certain intracellular signaling molecules. Recent advances demonstrated the AMPK to exert tumor suppressor activity realized through various signaling molecules by stimulating different cellular processes such as apoptosis, autophagy and cell growth and proliferation. AMPK can also be used to protect against metabolic syndrome. AMPK has previously been reported to be either directly or indirectly involved in the regulation of many different cellular transport proteins of high importance for cellular physiology and pathophysiology. Thus, AMPK provides a necessary link between cellular energy metabolism and cellular transport activities. A better understanding of the AMPK role in intracellular signaling under physiological and pathological conditions may represent a potential strategy for developing therapies for treating many different human diseases and disorders, in which AMPK plays a key role.