5'-AMP-activated protein kinase alpha subunit (AMPKα)

5'-AMP-activated protein kinase alpha subunit (AMPK alpha, AMPKα) is the catalytic subunit of the heterotrimeric AMPK complex, a central regulator of cellular and whole-body energy homeostasis. AMPK is activated by metabolic stresses causing increased AMP:ATP or ADP:ATP ratios, which activate the complex through allosteric mechanisms and by LKB1- or CaMKKβ-mediated phosphorylation of the Thr172 residue in the alpha-subunit kinase domain. Two isoforms (alpha-1/PRKAA1 and alpha-2/PRKAA2) exist in mammals, with tissue- and context-specific expression, forming twelve possible heterotrimeric combinations in complex with beta and gamma subunit isoforms. The alpha subunit's main biological role is to phosphorylate downstream targets to shift cellular metabolism toward ATP generation, inhibit anabolic processes, and restore energy balance. Pharmacological interest in AMPK alpha derives from its role as a drug target in metabolic diseases, cancer, and cardiovascular disease, with both indirect and direct activators in use or development. Notes on correctness: The query refers collectively to “5'-AMP-activated protein kinase alpha subunit isoforms.” This is not the canonical form of a molecular target—canonical targets are the specific isoforms, e.g., “5'-AMP-activated protein kinase catalytic subunit alpha-1” (PRKAA1) or “...alpha-2” (PRKAA2), rather than the class of alpha subunit isoforms as a group. For database purposes, canonical records should be for single, specific isoforms.

Other names

AMPK alphaAMPKα5'-AMP-activated protein kinase catalytic subunit alphaProtein kinase, AMP-activated, alpha subunitPRKAA1 (for alpha-1 isoform gene)PRKAA2 (for alpha-2 isoform gene)

Activation of AMPK increases its phosphorylation of downstream metabolic enzymes, shifting cellular programs from energy-consuming anabolic processes toward catabolic processes that generate ATP (increased glucose uptake, fatty acid oxidation, inhibition of lipogenesis and protein synthesis). Inhibits mTOR pathway (anticancer, antiproliferative effect) Indirect mechanisms for widely-used drugs like metformin involve LKB1-mediated phosphorylation of the AMPK alpha subunit.