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 PRKACA and PRKACB. Interacts with the phosphorylated form of PJA2. Forms a complex composed of PRKAR2B, GSK3B and GSKIP through GSKIP interaction; facilitates PKA-induced phosphorylation and regulates GSK3B activity. Colocalizes with PJA2 in the cytoplasm and at 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.