AMPK (AMP-activated Protein Kinases)
AMP-activated protein kinase (AMPK) is a heterotrimeric complex consisting of a catalytic a subunit and regulatory beta and gamma subunits. Each subunit exists as alternate isoforms (alpha 1, alpha 2, beta 1, beta 2, gamma 1, gamma 2, gamma 3), with all 12 combinations capable of forming complexes. The catalytic a subunit of AMPK is activated allosterically by AMP and by phosphorylation via the AMPK kinase LKB1. Active AMPK downregulates anabolic pathways such as fatty acid, triglyceride, and cholesterol synthesis, and up-regulates catabolic pathways such as glycolysis and fatty acid oxidation. AMPK's role in metabolic regulation has implicated this serine/threonine kinase as a therapeutic target in heart disease, obesity, and diabetes.