title: An intracellular modulator of the 3'5'-cGMP hydrolysis in growing Dictyostelium discoideum amoebae.
abstract: A heat-stable and acid-stable macromolecular factor present in the cytosol of growing Dictyostelium discoideum amoebae affects specifically the intracellular cGMP phosphodiesterase. It decreases the V of the enzyme but does not alter its Km. It has no effect on the cAMP or cGMP hydrolysis catalyzed by the intracellular cAMP-cGMP phosphodiesterases or by the extracellular phosphodiesterase. It is also expressed in a mutant (HPX235), defective in the synthesis of the cAMP-cGMP phosphodiesterases but capable of intracellular transduction of the chemotactic signal. This factor is resistant to several nucleases, proteases and phospholipases, and has an apparent molecular weight between 3500-10000. In contrast, the protein phosphodiesterase inhibitor secreted by the amoebae exerts an opposite inhibition on the intracellular phosphodiesterases. These two inhibitory factors may regulate intracellular cGMP hydrolysis during the chemotactic response.
mesh_terms: D015106:3',5'-Cyclic-GMP Phosphodiesterases / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology; D006152:Cyclic GMP / Q000378:metabolism*; D003600:Cytosol / Q000201:enzymology; D004023:Dictyostelium / Q000201:enzymology / Q000254:growth & development*; D006868:Hydrolysis; D009154:Mutation
chemical_list: D015106:3',5'-Cyclic-GMP Phosphodiesterases; D006152:Cyclic GMP