RI-STAD-2 is a high-affinity interfering peptide that regulates the subunit RI of protein kinase A ( PKA ). RI-STAD-2 interferes with the binding of AKAPs and PKA-RI by simulating the interaction between AKAPs' α-helix domain and PKA-RI's dimerization/anchoration (D/D) domain, thereby affecting PKA activity and intracellular localization. RI-STAD-2 can be used to study the role of AKAPs interaction with PKA-RI in pathological processes such as cardiovascular disease and cancer.