Regulation of chloride channel trafficking by cyclic AMP via protein kinase A-independent pathway in A6 renal epithelial cells.
The apical membrane of renal epithelial A6 cells has 3 and 8 pS Cl- channels. Both types of the channels were blocked by NPPB (5-Nitro-2-(3-phenylpropylamino)-benzoic acid; 100 microM). 8-bromo-cAMP (Br-cAMP) increased the open probability of 3 pS Cl- channel and this action was inhibited by pretreatment with H89, an inhibitor of cAMP-dependent protein kinase (PKA). On the other hand, the number of 8 pS Cl- channel was increased by Br-cAMP. The increase in number of 8 pS Cl- channel by Br-cAMP was inhibited by brefeldin A (a blocker of movement of membrane protein from an intracellular pool to the cell surface) but not by H89. These observations indicate that cAMP could activate the 3 pS Cl- channel through PKA-dependent phosphorylation, and that cAMP could stimulate translocation of the 8 pS Cl- channel through PKA-independent pathways. We conclude that PKA-independent pathways are involved in cAMP signaling mechanisms in addition to PKA-dependent pathways.
Shintani
Y
Y
Laboratory for Cellular and Molecular Physiology, Division of Respiratory Research, The Hospital for Sick Children Research Institute, The University of Toronto Faculty of Medicine, Ontario, Canada.
Marunaka
Y
Y
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology*; D000818:Animals; D020126:Brefeldin A; D002460:Cell Line; D018118:Chloride Channels / Q000187:drug effects / Q000502:physiology*; D000242:Cyclic AMP / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors*; D003517:Cyclopentanes / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D004848:Epithelium; D015640:Ion Channel Gating / Q000187:drug effects; D007546:Isoquinolines / Q000494:pharmacology*; D007668:Kidney; D007700:Kinetics; D018408:Patch-Clamp Techniques; D013449:Sulfonamides
D018118:Chloride Channels; D003517:Cyclopentanes; D004791:Enzyme Inhibitors; D007546:Isoquinolines; D013449:Sulfonamides; D020126:Brefeldin A; D015124:8-Bromo Cyclic Adenosine Monophosphate; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide