RT Journal Article SR Electronic T1 AMP-Activated Protein Kinase α2 Deficiency Affects Cardiac Cardiolipin Homeostasis and Mitochondrial Function JF Diabetes JO Diabetes FD American Diabetes Association SP 786 OP 794 DO 10.2337/db06-0187 VO 56 IS 3 A1 Athéa, Yoni A1 Viollet, Benoît A1 Mateo, Philippe A1 Rousseau, Delphine A1 Novotova, Marta A1 Garnier, Anne A1 Vaulont, Sophie A1 Wilding, James R. A1 Grynberg, Alain A1 Veksler, Vladimir A1 Hoerter, Jacqueline A1 Ventura-Clapier, Renée YR 2007 UL http://diabetes.diabetesjournals.org/content/56/3/786.abstract AB AMP-activated protein kinase (AMPK) plays an important role in controlling energy homeostasis and is envisioned as a promising target to treat metabolic disorders. In the heart, AMPK is involved in short-term regulation and in transcriptional control of proteins involved in energy metabolism. Here, we investigated whether deletion of AMPKα2, the main cardiac catalytic isoform, alters mitochondrial function and biogenesis. Body weight, heart weight, and AMPKα1 expression were similar in control littermate and AMPKα2−/− mice. Despite normal oxygen consumption in perfused hearts, maximal oxidative capacity, measured using saponin permeabilized cardiac fibers, was ∼30% lower in AMPKα2−/− mice with octanoate, pyruvate, or glutamate plus malate but not with succinate as substrates, showing an impairment at complex I of the respiratory chain. This effect was associated with a 25% decrease in mitochondrial cardiolipin content, the main mitochondrial membrane phospholipid that is crucial for complex I activity, and with a 13% decrease in mitochondrial content of linoleic acid, the main fatty acid of cardiolipins. The decrease in cardiolipin content could be explained by mRNA downregulation of rate-limiting enzymes of both cardiolipin synthesis (CTP:PA cytidylyltransferase) and remodeling (acyl-CoA:lysocardiolipin acyltransferase 1). These data reveal a new role for AMPKα2 subunit in the regulation of cardiac muscle oxidative capacity via cardiolipin homeostasis.