AMPK is a heterotrimer protein kinase consisting of an a catalytic subunit, and non-catalytic β and ? subunits. AMPK is an important energy-sensing enzyme that monitors cellular energy status. In response to cellular metabolic stresses, AMPK is activated and phosphorylates and inactivates acetyl-CoA carboxylase (ACC) and beta-hydroxy beta-methylglutaryl-CoA reductase (HMGCR), key enzymes involved in regulating biosynthesis of fatty acid and cholesterol.