Regulatory subunit of the cAMP-dependent protein kinases involved in cAMP signaling in cells. Type II regulatory chains mediate membrane association by binding to anchoring proteins, including the MAP2 kinase. The inactive form of the enzyme is composed of two regulatory chains and two catalytic chains. Activation by cAMP produces two active catalytic monomers and a regulatory dimer that binds four cAMP molecules. Interacts with AKAP4 and CBFA2T3. Interacts with the phosphorylated form of PJA2. Interacts with MYRIP. This interaction may link PKA to components of the exocytosis machinery, thus facilitating exocytosis, including insulin release (By similarity). Forms a complex composed of PRKAR2A, GSK3B and GSKIP through GSKIP interaction; facilitates PKA-induced phosphorylation and regulates GSK3B activity (PubMed:27484798). Interacts with ADCY8; inhibits adenylate cyclase activity through PKA phosphorylation (PubMed:22976297). Colocalizes with PJA2 in the cytoplasm and the cell membrane. Four types of regulatory chains are found: I-alpha, I-beta, II-alpha, and II-beta. Their expression varies among tissues and is in some cases constitutive and in others inducible. Phosphorylated by the activated catalytic chain. Belongs to the cAMP-dependent kinase regulatory chain family.