5'-AMP-activated protein kinase catalytic subunit alpha-2 (AMPKα2 (also written as AMPK alpha-2 or PRKAA2))

5'-AMP‑activated protein kinase catalytic subunit alpha‑2 is a key enzyme encoded by the PRKAA2 gene. It forms part of the heterotrimeric AMP‑activated protein kinase complex, which functions as a central regulator ("energy sensor") maintaining cellular energy balance. Upon sensing low ATP levels or increased AMP/ADP ratios—such as during exercise, fasting, or metabolic stress—the complex becomes activated. The α-subunit provides catalytic activity essential for phosphorylating downstream targets involved in metabolism. Through these actions, it stimulates processes that generate ATP—including glucose uptake and fatty acid oxidation—and inhibits anabolic processes like lipid synthesis that consume ATP. The enzyme plays critical roles in regulating whole-body insulin sensitivity, cardiovascular adaptation to ischemia/hypoxia, autophagy induction under stress conditions, inhibition of mTOR signaling/protein synthesis when energy is scarce, and modulation of gene expression related to metabolism. Dysfunctional regulation has been implicated in diseases such as type II diabetes mellitus and cardiovascular disorders.

Other names

PRKAA2AMPK alpha-2AMP-activated protein kinase catalytic subunit alpha 2AAPK2_HUMAN (UniProt identifier)

Drugs such as metformin activate AMPK by increasing the AMP/ATP ratio or through upstream kinases. Activation leads to: - Increased glucose uptake in muscle cells - Inhibition of hepatic gluconeogenesis - Enhanced fatty acid oxidation AICAR acts as an AMP mimetic to directly activate AMPK.