【多选题】How does cAMP exert its effects via activating cyclic- AMP-dependent protein kinase (PKA) ?
A.
Cyclic AMP exerts most of its effects by activating the enzyme cyclic- AMP-dependent protein kinase (PKA).
B.
This enzyme is normally held inactive in a complex with a regulatory protein. The binding of cyclic AMP to the regulatory protein forces a conformational change that releases the inhibition and unleashes the active kinase.
C.
Activated PKA then catalyzes the phosphorylation of particular serines or threonines on specific intracellular proteins, thus altering the activity of these target proteins.
D.
In different cell types, different sets of proteins are available to be phosphorylated, which largely explains why the effects of cyclic AMP vary with the type of target cell.