Elevated intracellular Ca2+ acts through protein kinase C to regulate rabbit ileal NaCl absorption. Evidence for sequential control by Ca2+/calmodulin and protein kinase C
| Autor: | M. Gould, G. W G Sharp, Mark Donowitz, M. E. Cohen |
|---|---|
| Rok vydání: | 1989 |
| Předmět: |
Intracellular Fluid
Male Calmodulin Biological Transport Active Arachidonic Acids Sodium Chloride Piperazines Intestinal absorption Electrolytes Cytosol Ileum 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine Ca2+/calmodulin-dependent protein kinase Animals Phosphorylation Protein Kinase C Protein kinase C Sulfonamides Microvilli biology Chemistry Binding protein Cell Membrane General Medicine Isoquinolines Molecular biology Body Fluids Intestinal Absorption Biochemistry Prostaglandin-Endoperoxide Synthases biology.protein Calcium Rabbits Nucleotides Cyclic Intracellular Research Article |
| Zdroj: | Journal of Clinical Investigation. 83:1953-1962 |
| ISSN: | 0021-9738 |
| DOI: | 10.1172/jci114104 |
| Popis: | Calcium/calmodulin is involved in the regulation of basal rabbit ileal active Na and Cl absorption, but the mechanism by which elevated intracellular Ca2+ affects Na and Cl transport is unknown. To investigate the roles of the Ca2+/calmodulin and protein kinase C systems in ileal NaCl transport, two drugs, the isoquinolenesulfonamide, H-7, and the naphthalenesulfonamide, W13, were used in concentrations that conferred specificity in the antagonism of protein kinase C (60 microM H-7) and Ca2+/calmodulin (45 microM W13), respectively, as determined using phosphorylation assays in ileal villus cells. W13 but not H-7 stimulated basal active NaCl absorption. H-7 inhibited changes in Na and Cl absorption caused by maximal concentrations of Ca2+ ionophore A23187 and carbachol and serotonin, secretagogues that act by increasing cytosol Ca2+, while W13 had no effect. In contrast, neither H-7 nor W13 altered the change in NaCl transport caused by the cyclic nucleotides 8-Br-cAMP and 8-Br-cGMP. These data suggest that: (a) basal rabbit ileal NaCl absorption is regulated by the Ca2+/calmodulin complex and not by protein kinase C; (b) the effect of elevating intracellular Ca2+ to decrease NaCl absorption is mediated via protein kinase C but not by Ca2+/calmodulin; (c) the effects of protein kinase C are not overlapping or synergistic with those of Ca2+/calmodulin on either basal absorption or on the effects of increased Ca2+; and (d) neither Ca2+/calmodulin nor protein kinase C are involved in the effects of cAMP and cGMP on ileal active NaCl transport. |
| Databáze: | OpenAIRE |
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