Part of the osmoregulatory pathway which leads to the increase of intracellular cAMP concentration in response to hyperosmotic stress. Thought to negatively regulate the rdeA-regA pathway by acting as a phosphatase towards the HPt protein rdeA. Has probably no histidine kinase activity. Expression increases during the late culmination stage. Under osmotic stress conditions, this protein undergoes phosphorylation at a serine residue in the kinase core, which is not due to an autophosphorylation of dokA. This is in contrast to the classic two-component paradigm, which predicts only histidine and aspartate phosphorylation. Elevated levels of cAMP.