AMP-activated protein kinase (AMPK) is highly conserved from yeast to plants and animals and plays a key role in the regulation of energy homeostasis. AMPK is a heterotrimeric complex composed of a catalytic alpha subunit and regulatory beta and gamma subunits, each of which is encoded by two or three distinct genes (alpha1, 2, beta1, 2, gamma1, 2, 3). The kinase is activated by an elevated AMP/ATP ratio due to cellular and environmental stress, such as heat shock, hypoxia, and ischemia.
