After the adenylyl cyclase reaction (which convert ATP into cyclic adenosine monophosphate-cAMP), cAMP level is directly increased. Next steps of PKA activation include:
• cAMP binding to regulatory subunits of PKA, as a result conformational change in the regulatory subunits of PKA is induced,
• catalytic subunits are detached and unleashed by regulatory subunits and as a result activated.