title: A slowly dissociating form of the cell surface cyclic adenosine 3':5'-monophosphate receptor of Dictyostelium discoideum.
abstract: Experiments using a phosphodiesterase-minus mutant of Dictyostelium discoideum indicate that ligand-induced loss of cell surface cyclic adenosine 3':5'-monophosphate binding sites (down regulation) can be evoked with concentrations of cyclic adenosine 3':5'-monophosphate as low as 10(-8) M. The loss of receptor sites is observed after 5 min of cell preincubation with cyclic adenosine 3':5'-monophosphate and can be as extensive as 75 to 80%. This decrease in binding sites is correlated with the appearance of a slowly dissociating cyclic adenosine 3':5'-monophosphate binding component. Radioactive cyclic adenosine 3':5'-monophosphate bound to this form of receptor cannot be competed for by nonradioactive cyclic adenosine 3':5'-monophosphate or adenosine 5'-monophosphate and is not accessible to hydrolysis by cyclic adenosine 3':5'-monophosphate phosphodiesterase. The extent of appearance of this binding component is dependent upon the concentration of cyclic adenosine 3':5'-monophosphate used to elicit the down regulation response and the temperature of the incubation medium.
mesh_terms: D000242:Cyclic AMP / Q000378:metabolism; D004023:Dictyostelium / Q000378:metabolism*; D007700:Kinetics; D009154:Mutation; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D011953:Receptors, Cyclic AMP / Q000378:metabolism*
chemical_list: D011953:Receptors, Cyclic AMP; D000242:Cyclic AMP; D010727:Phosphoric Diester Hydrolases