Phosphorylase B Kinase Regulatory Subunit Alpha (PHKA2) ELISA Kit for Human

Phosphorylase kinase is a polymer of 16 subunits, four each of alpha, beta, gamma and delta. The alpha subunit includes the skeletal muscle and hepatic isoforms, and the hepatic isoform is encoded by this gene. The beta subunit is the same in both the muscle and hepatic isoforms, and encoded by one gene. The gamma subunit also includes the skeletal muscle and hepatic isoforms, which are encoded by two different genes. The delta subunit is a calmodulin and can be encoded by three different genes. The gamma subunits contain the active site of the enzyme, whereas the alpha and beta subunits have regulatory functions controlled by phosphorylation. The delta subunit mediates the dependence of the enzyme on calcium concentration. Mutations in this gene cause glycogen storage disease type 9A, also known as X-linked liver glycogenosis. Alternatively spliced transcript variants have been reported, but the full-length nature of these variants has not been determined.[provided by RefSeq, Feb 2010]

PHKA2: Phosphorylase b kinase catalyzes the phosphorylation of serine in certain substrates, including troponin I. The alpha chain may bind calmodulin. Defects in PHKA2 are the cause of glycogen storage disease type 9A (GSD9A); also known as X-linked liver glycogenosis (XLG). GSD9A is a metabolic disorder resulting in a mild glycogenosis with clinical symptoms that include hepatomegaly, growth retardation, muscle weakness, elevation of glutamate-pyruvate transaminase and glutamate-oxaloacetate transaminase, hypercholesterolemia, hypertriglyceridemia, and fasting hyperketosis. Two subtypes are known: type 1 or classic type with no phosphorylase kinase activity in liver or erythrocytes, and type 2 or variant type with no phosphorylase kinase activity in liver, but normal activity in erythrocytes. Unlike other glycogenosis diseases, glycogen storage disease type 9A is generally a benign condition. Patients improve with age and are often asymptomatic as adults. Accurate diagnosis is therefore also of prognostic interest. Belongs to the phosphorylase b kinase regulatory chain family.

Protein type: Protein kinase, regulatory subunit

Chromosomal Location of Human Ortholog: Xp22.13

Cellular Component: cytosol; phosphorylase kinase complex; plasma membrane

Molecular Function: calmodulin binding; phosphorylase kinase activity; protein binding

Biological Process: carbohydrate metabolic process; cellular protein modification process; generation of precursor metabolites and energy; glycogen catabolic process; protein amino acid phosphorylation

Disease: Glycogen Storage Disease Ixa1