5'-AMP-activated protein kinase subunit gamma-3 (PRKAG3) (PRKAG3)

5'-AMP-activated protein kinase (AMPK) is a heterotrimeric enzyme that serves as a master regulator of cellular energy homeostasis. The gamma-3 subunit (PRKAG3) is a regulatory isoform uniquely expressed in skeletal muscle, particularly in fast-twitch glycolytic fibers (UniProt P54619). AMPK gamma-3-containing complexes are activated by increases in the cellular AMP:ATP ratio, which occurs during exercise or metabolic stress, leading to the stimulation of insulin-independent glucose uptake and fatty acid oxidation (PubMed 11146552). Because of its muscle-specific expression, the gamma-3 subunit is a highly attractive therapeutic target for metabolic diseases like type 2 diabetes, as its activation can improve insulin sensitivity and systemic glucose clearance without the side effects associated with broader AMPK activation in the heart or liver (PubMed 10666471). Pharmacological agents such as MK-8722 and PF-06409577 have been developed to target AMPK complexes, demonstrating potent glucose-lowering effects in preclinical models (PubMed 27339886). However, achieving high selectivity for the gamma-3 isoform remains a significant challenge in drug development to avoid potential cardiac hypertrophy or other complications associated with the gamma-1 and gamma-2 isoforms.

Other names

PRKAG3AMPK gamma-35'-AMP-activated protein kinase subunit gamma-3Protein kinase AMP-activated non-catalytic subunit gamma 3AMP-activated protein kinase gamma-3 heterotrimer

Direct allosteric activation and protection of the catalytic alpha-subunit from dephosphorylation at Thr172 upon binding of AMP, ADP, or synthetic activators to the Bateman domains of the gamma-3 subunit (UniProt P54619).