CAMP-dependent protein kinase

Function

cAMP-dependent protein kinase (PKA) is involved in regulation of glycogen, sugar and lipid metabolism. PKA activity depends on the level of cyclic AMP (cAMP) in the cell. PKA contains a catalytic subunit and a regulatory subunit. PKA catalytic subunit catalyzes the transfer of ATP phosphate to serine or threonine of protein substrates. Regulatory subunits exist as type I and type II. Each type contains 2 subtypes: α and β. The types and subtypes differ in their tissue distribution. PKA II catalyzes autophosphorylation in which a phosphate group of ATP is attached to a Ser residue in the regulatory subunit. Additional details and references in:

• CAMP Dependent Protein Kinase, Catalytic Subunit
• Eukaryotic Protein Kinase Catalytic Domain
• Protein Kinase A.

Structural highlights

In the absence of cAMP, PKA is an inactive tetramer with 2 catalytic subunits and 2 regulatory subunits. The regulatory subunit contains inhibitory region, two cAMP-binding domains and a C-terminal dimerization domain. The catalytic subunit contains an ATP-binding domain and a regulatory subunit binding domain.

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