Identification and characterization of the adenosine 3′,5′-cyclic monophosphate binding proteins appearing during the development of Dictyostelium discoideum

A photosensitive, radioactive analogue of cyclic adenosine monophosphate, 8-azido-adenosine 3′,5′-³²P]monophosphate (8-N₃-cyclic AMP), was used to label the cyclic AMP binding proteins of Dictyostelium discoideum. During development cytosolic proteins appear which are specifically labeled by the photoaffinity agent. The proteins are developmentally regulated since they are only found in starved, developing cells. Unlabeled cyclic AMP competes specifically with the labeled analogue for protein binding sites in contrast to unlabeled 5′-AMP which does not compete. A mutant which develops spores but is deficient in stalk cell production produces a different set of cyclic AMP binding proteins from the parent strain.