Regulation of an epithelial chloride channel by direct phosphorylation and dephosphorylation.
A native chloride channel in Necturus gallbladder epithelial cells is opened by a theophylline-induced rise in cellular cyclic AMP and is closed by removal of theophylline or by addition of specific antibody; however, it does not close if okadaic acid, an inhibitor of protein phosphatases 1 and 2A, is added. The purified channel reconstituted into lipid bilayers closes upon the addition of protein phosphatase 2A and is reopened by the addition of Mg-ATP and the catalytic subunit of cyclic AMP-dependent protein kinase. These results indicate that the channel protein is purified in a phosphorylated state and that its functional characteristics are at least partly controlled by direct phosphorylation and dephosphorylation.
Finn
A L
AL
Department of Medicine, University of North Carolina, Chapel Hill 27599.
Gaido
M L
ML
Dillard
M
M
Brautigan
D L
DL
D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D018118:Chloride Channels; D002712:Chlorides / Q000378:metabolism; D004847:Epithelial Cells; D004848:Epithelium / Q000378:metabolism; D004988:Ethers, Cyclic / Q000494:pharmacology; D005704:Gallbladder / Q000166:cytology / Q000378:metabolism*; D008051:Lipid Bilayers / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D009337:Necturus; D019319:Okadaic Acid; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors; D010766:Phosphorylation; D054648:Protein Phosphatase 2; D013806:Theophylline / Q000494:pharmacology
D018118:Chloride Channels; D002712:Chlorides; D004988:Ethers, Cyclic; D008051:Lipid Bilayers; D008565:Membrane Proteins; D019319:Okadaic Acid; D013806:Theophylline; D010749:Phosphoprotein Phosphatases; D054648:Protein Phosphatase 2