Abstract
Background Calpain, intracellular non-lysosomal calcium-dependent proteinase, is activated by a number of signaling pathways that lead to the elevation of intraplatelet calcium concentrations. Physiological roles of calpain, highly expressed in platelets, include regulation of platelet aggregation and adhesion, while excessive activation of calpain in such pathological disorders as diabetes could cause changes in platelet functions, resulting in platelet hyperactivation. Platelets from diabetic patients are also characterized by resistance to nitric oxide inhibition. Here we examined if calpain could regulate major cAMP and cGMP hydrolyzing phosphodiesterases (PDEs), PDE3A and PDE5, in human platelets.
Highlights
Calpain, intracellular non-lysosomal calcium-dependent proteinase, is activated by a number of signaling pathways that lead to the elevation of intraplatelet calcium concentrations
Our data showed that calpain was responsible for cleavage of PDE3A and PDE5
Calpain, activated by an increase of cytoplasmic Ca, induced limited proteolysis of cyclic nucleotide PDEs, whereas calpeptin, a calpain inhibitor, was able to block the proteolytic effects of calpain
Summary
Intracellular non-lysosomal calcium-dependent proteinase, is activated by a number of signaling pathways that lead to the elevation of intraplatelet calcium concentrations. Calcium/Calpain mediated regulation of cyclic nucleotide phosphodiesterases, PDE3A and PDE5, in human platelets Irina G Rybalkina, Masami Shimizu-Albergine, Sergei D Rybalkin* From 5th International Conference on cGMP: Generators, Effectors and Therapeutic Implications Halle, Germany.
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