Chemical modification studies on the Ca2+ion-dependent protein modulator of cyclic nucleotide phosphodiesterase

Biochemistry ◽  
1977 ◽  
Vol 16 (12) ◽  
pp. 2742-2749 ◽  
Author(s):  
Michael Walsh ◽  
Frits C. Stevens
Keyword(s):  
Chemical Modification ◽  
Cyclic Nucleotide ◽  
Cyclic Nucleotide Phosphodiesterase ◽  
Dependent Protein

Regulation of cAMP concentration by calmodulin-dependent cyclic nucleotide phosphodiesterase

1986 ◽  
Vol 64 (11) ◽  
pp. 1072-1080 ◽  
Author(s):  
Rajendra K. Sharma ◽  
Jerry H. Wang
Keyword(s):  
Protein Kinase ◽  
Cyclic Nucleotide ◽  
Bovine Brain ◽  
Cyclic Nucleotide Phosphodiesterase ◽  
Camp Concentration ◽  
Dependent Protein Kinase ◽  
Camp Dependent Protein Kinase ◽  
Dependent Protein ◽  
Molecular Masses ◽  
Regulatory Properties

Bovine brain contains two major calmodulin (CaM) dependent phosphodiesterase isozymes which are homodimeric proteins with subunit molecular masses of 60 and 63 kilodaltons (kDa), respectively. The 60-kDa subunit isozyme can be phosphorylated by cAMP-dependent protein kinase, resulting in a decrease in the enzyme affinity towards CaM. The phosphorylation is blocked by Ca2+ and CaM and reversed by the CaM-stimulated phosphatase (calcineurin). The 63-kDa subunit isozymes can also be phosphorylated, but in this case by a CaM-dependent protein kinase(s). This phosphorylation is also accompanied by a decrease in the isozyme affinity towards CaM and can be reversed by the CaM-dependent phosphatase. Analysis of the complex regulatory properties of the phosphodiesterase isozymes has led to the suggestion that fluxes of cAMP and Ca2+ during cell activations are closely coupled and that the CaM-dependent phosphodiesterase isozymes play key roles in this signal coupling phenomenon.

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