Phosphorylase kinase regulatory subunit alpha 1 (PHKA1)

Phosphorylase kinase regulatory subunit alpha 1 is the alpha subunit of the muscle isoform of phosphorylase kinase, a large multi-subunit enzyme complex essential for glycogen breakdown in skeletal muscle[2][3]. The PHKA1 gene encodes this subunit. Together with the beta and delta (calmodulin) regulatory subunits, alpha 1 modulates the activity of the gamma catalytic subunit in response to hormonal, neural, and calcium signals, thereby regulating energy production. The alpha subunit is phosphorylated by protein kinase A (PKA), enhancing activation in response to cAMP signaling. Mutations in PHKA1 cause glycogen storage disease type IXd, and dysregulation of the complex has also been associated with some tumors[1][2][3].

Other names

Phosphorylase b kinase regulatory subunit alpha, skeletal muscle isoformPHKA1PhK α1 subunitAlpha-1 subunit of muscle phosphorylase kinase

Allosteric activation of glycogen phosphorylase via regulatory effects on the enzymatic complex Activation by phosphorylation (via PKA) and Ca²⁺/calmodulin binding