Regulator of the cAMP signaling pathway specific to sexual development. Controls the levels of external cAMP by regulating the expression of phosphodiesterase pdsA and its inhibitor pdiA. Expression in fusion-competent cells is about 6 times higher than fusion-incompetent cells. Remains high until 8 hours of sexual development, and then slightly decreases. In the asexual development, the transcript level increases temporarily during the pre-aggregation stage (4 hours), and then returns to the basal level. Null cells produce tiny macrocysts and have increased numbers of peripheral cells during sexual development. Macrocyst formation by null cells is much less sensitive to the addition of exogenous cAMP compared to wild-type. The mRNA level of phosphodiesterase (pdsA) is higher and that of its inhibitor (pdiA) is lower in the null cells compared to wild-type during sexual development. The expression of regA, which regulates the intercellular cAMP signaling pathway is not affected. Null cells show less extensive cell aggregation toward the zygote giant cells and many cells remain around poorly formed macrocysts. The expression of the carA is unchanged or slightly higher in the null cells, while that of the carC is much reduced. Chemotaxis toward cAMP during asexual development is indistinguishable between the wild-type and null cells.