Signal transduction: regulation of cAMP concentration in cardiac muscle by calmodulin-dependent cyclic nucleotide phosphodiesterase.
The bovine heart calmodulin-dependent phosphodiesterase can be phosphorylated by cAMP-dependent protein kinase, resulting in a decrease in the enzyme's affinity for calmodulin. The phosphorylation of calmodulin-dependent phosphodiesterase is blocked by Ca2+ and calmodulin and reversed by the calmodulin-dependent phosphatase. The dephosphorylation is accompanied by an increase in the affinity of the phosphodiesterase for calmodulin. The CaM-dependent phosphodiesterase isozymes of heart and brain are regulated by calmodulin, but the affinity for calmodulin are different. Furthermore, the bovine heart CaM-dependent phosphodiesterase isozyme in stimulated at much lower Ca2+ concentration than the bovine brain isozymes. Results from this study suggest that the activity of this phosphodiesterase is precisely regulated by cross-talk between Ca2+ and cAMP signalling pathways.
Sharma
R K
RK
Department of Pathology, Royal University Hospital, University of Saskatchewan, Saskatoon, Canada.
D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002147:Calmodulin / Q000378:metabolism*; D002148:Calmodulin-Binding Proteins / Q000378:metabolism; D002417:Cattle; D000242:Cyclic AMP / Q000378:metabolism*; D054677:Cyclic Nucleotide Phosphodiesterases, Type 1; D009206:Myocardium / Q000378:metabolism*; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D010766:Phosphorylation; D015398:Signal Transduction
D002147:Calmodulin; D002148:Calmodulin-Binding Proteins; D000242:Cyclic AMP; D010749:Phosphoprotein Phosphatases; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D054677:Cyclic Nucleotide Phosphodiesterases, Type 1; D002118:Calcium