Sensing and responding to energetic stress: Evolution of the AMPK network.

AMP-activated protein kinase is an enzyme that mediates communication between cellular energy status and diverse effector proteins, particularly those that play roles in determining the metabolic phenotype. By phosphorylating metabolic enzymes, transcriptional regulators and proteins involved in cellular structure, it can modify energy metabolism in both the short term and long term. Its basic features are highly conserved, with homologues in all eukaryotes. Gene and/or genome duplications endowed early vertebrates with paralogs of AMPK subunits, though the nature of their subfunctionalization remains uncertain, even in mammals. While most research focuses on the role of the enzyme in human health, a great deal can be learned from comparative studies targeting non-traditional model animals. Fish, in particular, are interesting models because of the diversity in the metabolic properties and complex relationships between metabolism and environmental challenges. In this review, we examine what is known about AMPK structure and function though the lens of comparative physiology, looking for opportunities to better understand how this vital energy sensor has evolved in animals.