Protein kinase A (PKA). which regulates a diverse set of biological functions downstream of cyclic AMP (cAMP). is a tetramer consisting of two catalytic subunits (PKA-C) and two regulatory subunits (PKA-R). When cAMP binds the PKA-R subunits. https://www.jmannino.com/mega-pick-NFL-San-Francisco-49ers-Zone-Block-iPhone-14-Pro-MagSafe-Case-p80213-quick-pick/