Phosphodiesterase specific for cAMP. Involved in the degradation of intracellular cAMP. Morphological suppressor of tagB. Phosphorelay protein that accepts phosphate from rdeA or supplies phosphate from regA; depending on the relative concentration of the phosphodonor proteins. 3',5'-cyclic AMP + H2O = AMP + H(+) Binds 2 divalent metal cations per subunit. Site 1 may preferentially bind zinc ions, while site 2 has a preference for magnesium and/or manganese ions. Inhibited by 3-isobutyl-1-methylxanthine (IBMX). cAMP/cGMP selectivity of 200. Expressed at low levels in vegetative cells and at high levels in prespore and prestalk cells during development. Developmentally regulated. Not observable before the end of aggregation, peaks at the mound stage and remains at a lower level thereafter. Down-regulated by phagocytic stimuli. The phosphorelay mechanism involves the sequential transfer of a phosphate group from Asp-212 of pde2 to 'His-65' of rdeA. Phosphorylation of Asp-212 activates the phosphodiesterase domain. Rapid development. Cells are 4-fold more resistant to the antitumor agent cisplatin than are wild-type cells. Additionally it produces fruiting bodies with spore masses that cannot rise up the stalk during development. Mutant cells grow exponentially at the same rate as wild-type. Disruption of regA in a tagB null or in a tagC null background resulted in higher levels of sporulation. Disruption of regA in a dhka null background corrects the defect in stalk formation and suppresses the block to sporulation. Belongs to the cyclic nucleotide phosphodiesterase family.