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Calcium‐dependent nitric oxide synthesis in endothelial cytosol is mediated by calmodulin
Author(s) -
Busse Rudi,
Mülsch Alexander
Publication year - 1990
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(90)80902-u
Subject(s) - calmodulin , cytosol , nitric oxide , nitric oxide synthase , mastoparan , melittin , chemistry , biochemistry , calcium , enzyme , signal transduction , peptide , g protein , organic chemistry
We investigated whether calmodulin mediates the stimulating effect of Ca 2+ on nitric oxide synthase in the cytosol of porcine aortic endothelial cells. Nitric oxide was quantified by activation of a purified soluble guanylate cyclase. The Ca 2+ ‐sensitivity of nitric oxide synthase was lost after anion exchange chromatography of the endothelial cytosol and could only be reconstituted by addition of calmodulin or heat‐denatured endothelial cytosol. The Ca 2+ ‐dependent activation of nitric oxide synthase in the cytosol was inhibited by the calmodulin‐binding peptides/proteins melittin, mastoparan, and calcineurin (IC 50 450, 350 and 60 nM, respectively), but not by the calmodulin antagonist, calmidazolium. In contrast, Ca 2+ ‐calmodulin‐reconstituted nitric oxide synthase was inhibited with similar potency by melittin and calmidazolium. The results suggest that the Ca 2+ ‐dependent activation of nitric oxide synthase in endothelial cells is mediated by calmodulin.