Calmodulin-dependent cyclic nucleotide phosphodiesterase (PDE1)

• Published in: Cellular and molecular life sciences : CMLS Vol. 55; no. 8-9; pp. 1164 - 1186
• Main Authors: Kakkar, R, Raju, R V, Sharma, R K
• Format: Journal Article
• Language: English
• Published: Switzerland Springer Nature B.V 01.07.1999; Birkhäuser Verlag
• Subjects: 3',5'-Cyclic-AMP Phosphodiesterases - antagonists & inhibitors; 3',5'-Cyclic-AMP Phosphodiesterases - chemistry; 3',5'-Cyclic-AMP Phosphodiesterases - genetics; 3',5'-Cyclic-AMP Phosphodiesterases - physiology; 3',5'-Cyclic-GMP Phosphodiesterases - antagonists & inhibitors; 3',5'-Cyclic-GMP Phosphodiesterases - chemistry; 3',5'-Cyclic-GMP Phosphodiesterases - genetics; 3',5'-Cyclic-GMP Phosphodiesterases - physiology; 3',5'-Cyclic-nucleotide phosphodiesterase; Alternative splicing; Animals; Antagonists; Brain - enzymology; Calcium; Calcium Signaling - physiology; Calcium-binding protein; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Calcium-Calmodulin-Dependent Protein Kinases - physiology; Calmodulin; Calmodulin - physiology; Calpain; Calpain - physiology; Cardiac muscle; Cattle; Cell activation; Cell proliferation; Cyclic AMP; Cyclic AMP - physiology; Cyclic Nucleotide Phosphodiesterases, Type 1; Cyclic nucleotides; Cysteine proteinase; dihydropyridine; Drug development; Enzyme Activation; Enzymes; Ginseng; Glutamic acid; Humans; Immunology; Isoenzymes; Isoenzymes - antagonists & inhibitors; Isoenzymes - chemistry; Isoenzymes - genetics; Isoenzymes - physiology; Kinetics; Male; Muscle contraction; Neoplasm Proteins - physiology; Neoplasms - enzymology; Nerve Tissue Proteins - physiology; Organ Specificity; Parkinson Disease - enzymology; Pests; Pharmacology; Phosphoric Diester Hydrolases; Phosphorylation; Physiology; Proline; Protein Processing, Post-Translational; Protein Structure, Tertiary; Proteins; Proteolysis; Rats; RNA Splicing; Second Messenger Systems - physiology; Second messengers; Serine; Signal transduction; Structural proteins; Threonine; Transcription factors
• ISSN: 1420-682X; 1420-9071
• DOI: 10.1007/s000180050364

Ca2+/calmodulin-dependent cyclic nucleotide phosphodiesterase (PDE1) is one of the key enzymes involved in the complex interactions between the cyclic nucleotide and Ca2+ second messenger systems. Currently, three genes encode PDE1, and alternate splicing of these genes gives rise to functionally different isozymes which exhibit distinct catalytic and regulatory properties. Some isozymes have similar kinetic and immunological properties but are differentially regulated by Ca2+ and calmodulin. These isozymes also differ in their mechanism of regulation by phosphorylation. Analysis of various regulatory reactions involving Ca2+ and cyclic adenosine monophosphate (cAMP) has revealed the importance of the time dependence of these reactions during cell activation; however, no measurement is available for the time of occurrence of specific regulatory reactions. cAMP-signalling systems provide a pivotal centre for achieving crosstalk regulation by various signalling pathways. It has been proposed that polypeptide sequences enriched in proline (P), glutamate (E), serine (S) and threonine (T), known as PEST motifs, serve as putative intramolecular signals for rapid proteolytic degradation by calpains. Calpains are Ca(2+)-dependent cysteine proteases that regulate various enzymes, transcription factors and structural proteins through limited proteolysis. Isozyme PDE1A2 has a PEST motif and acts as a substrate for m-calpain. In this paper, we have described PDE1A2 regulation by calpains and its physiological implications. cAMP is an important component of the signal transduction pathway and plays an integral role in various physiological processes such as gene transcription, various neuronal functions, cardiac muscle contraction, vascular relaxation, cell proliferation and a host of other functions. It is important to identify the cellular processes where PDE isoform(s) and cAMP response are altered. This will lead to better understanding of the pathology of disease states and development of novel therapeutics. The different PDE1 isozymes, although similar in kinetic properties, can be distinguished by various pharmacological agents. Our recent understanding of the role of PDE1 inhibitors such as ginseng, dihydropy-ridine antagonists and antiparkinsonian agents are described in this review. The exact function of PDE1 isozymes in various pathophysiological processes is not clear because most of the studies have been carried out in vitro; therefore, it is essential that further research be directed to in vivo studies.