APC/CY7-Linked Polyclonal Antibody to Protein Kinase, AMP Activated Alpha 2 (PRKAa2)

The protein encoded by this gene is a catalytic subunit of the AMP-activated protein kinase (AMPK). AMPK is a heterotrimer consisting of an alpha catalytic subunit, and non-catalytic beta and gamma subunits. AMPK is an important energy-sensing enzyme that monitors cellular energy status. In response to cellular metabolic stresses, AMPK is activated, and thus phosphorylates and inactivates acetyl-CoA carboxylase (ACC) and beta-hydroxy beta-methylglutaryl-CoA reductase (HMGCR), key enzymes involved in regulating de novo biosynthesis of fatty acid and cholesterol. Studies of the mouse counterpart suggest that this catalytic subunit may control whole-body insulin sensitivity and is necessary for maintaining myocardial energy homeostasis during ischemia. [provided by RefSeq, Jul 2008]

AMPKA2: a catalytic subunit of AMP-activated protein kinase (AMPK). Acts as an energy sensor, playing a key role in regulating cellular energy metabolism. A protein kinase of the CAMKL family whose activation is regulated by the balance between ADP/AMP/ATP, and intracellular Ca(2+) levels. Acts as a metabolic stress-sensing protein kinase switching off biosynthetic pathways when cellular ATP levels are depleted and when 5'-ADP and -AMP rise in response to fuel limitation and/or hypoxia. Activates energy-producing pathways and inhibits energy-consuming processes. Restores ATP levels in cells by switching off anabolic and switching on catabolic pathways. Activated primarily by rising ADP levels and not, as previously thought, solely by AMP. AMPK resembles an adenylate charge regulatory system in which anabolic and catabolic pathways are regulated by adenine nucleotide ratios. Acts via direct phosphorylation of metabolic enzymes and transcription regulators. Regulates fatty acid synthesis by phosphorylating acetyl-CoA carboxylase. Regulates cholesterol synthesis by phosphorylating and inactivating hormone-sensitive lipase and hydroxymethylglutaryl-CoA reductase. Activated by at least two distinct upstream kinases: the tumor suppressor LKB1 and CaMKK2. Also acts as a regulator of cellular polarity by remodeling the actin cytoskeleton, probably by indirectly activating myosin. AMPK is a heterotrimer of an alpha catalytic subunit (AMPKA1 or -2), a beta (AMPKB1 or -2) and a gamma non-catalytic subunit (AMPKG1, -2 or -3). Different possible combinations of subunits give rise to 12 different holoenzymes. Binding of ADP or AMP to non-catalytic gamma subunit (PRKAG1, -2 or -3) results in allosteric activation. AMPK is activated by antihyperglycemic drug metformin, a drug prescribed to patients with type 2 diabetes: in vivo, metformin seems to mainly inhibit liver gluconeogenesis. However, metformin can be used to activate AMPK in muscle and other cells in culture or ex vivo. Selectively inhibited by compound C (6-[4-(2-Piperidin-1-yl-ethoxy)-phenyl)]-3-pyridin-4-yl-pyyrazolo[1,5-a] pyrimidine. Activated by resveratrol, a natural polyphenol present in red wine, and S17834, a synthetic polyphenol. Salicylate/aspirin directly activates kinase activity. Studies in the mouse suggest that AMPK2 may control whole-body insulin sensitivity and is necessary for maintaining myocardial energy homeostasis during ischemia.

Protein type: AMPK subfamily; Autophagy; CAMK group; CAMKL family; EC 2.7.11.1; EC 2.7.11.27; EC 2.7.11.31; Kinase, protein; Protein kinase, CAMK; Protein kinase, Ser/Thr (non-receptor)

Chromosomal Location of Human Ortholog: 1p32.2

Cellular Component: AMP-activated protein kinase complex; cytoplasm; cytosol; nucleoplasm; nucleus

Molecular Function: AMP-activated protein kinase activity; chromatin binding; histone serine kinase activity; protein binding; protein kinase activity; protein serine/threonine kinase activity; protein serine/threonine/tyrosine kinase activity

Biological Process: carnitine shuttle; cell cycle arrest; cellular response to glucose starvation; cellular response to nutrient levels; fatty acid homeostasis; glucose homeostasis; lipid biosynthetic process; macroautophagy; negative regulation of apoptosis; negative regulation of TOR signaling pathway; positive regulation of autophagy; positive regulation of glycolysis; positive regulation of macroautophagy; protein amino acid phosphorylation; regulation of circadian rhythm; regulation of fatty acid biosynthetic process; regulation of macroautophagy; response to stress; signal transduction