Cyclic AMP Receptor (Protein Kinase A Regulatory Subunit) (None)

The cyclic AMP receptor, commonly referred to as the regulatory subunit of Protein Kinase A (PKA), is a critical component in cellular signaling. PKA is a tetrameric enzyme composed of two regulatory and two catalytic subunits. The regulatory subunits are responsible for sensing intracellular levels of cyclic adenosine monophosphate (cAMP) and controlling the activation state of the kinase. In resting cells, R and C subunits form an inactive complex. When intracellular cAMP levels rise—often due to G protein-coupled receptor signaling—cAMP binds to the R subunits. This induces a conformational change, causing dissociation of active C subunits from the R dimer. Freed C subunits phosphorylate serine/threonine residues on target proteins, propagating downstream effects such as metabolic regulation or gene expression changes. The dimerization/docking domain on R-subunits allows interaction with A-Kinase Anchoring Proteins (AKAPs), which localize PKA complexes within specific cellular compartments such as plasma membrane or mitochondria for spatially restricted signaling responses. Mutations in the major gene, PRKAR1A, can lead to dysregulation associated with various diseases including endocrine disorders and certain cancers.

Other names

Protein kinase A regulatory subunitPKA regulatory subunit

Allosteric modulator of PKA catalytic subunit activity