Regulation of an epithelial chloride channel by direct phosphorylation and dephosphorylation
Finn, A.L.; Gaido, M.L.; Dillard, M.; Brautigan, D.L.
American Journal of Physiology 263(1 Pt 1): C172-C175
1992
ISSN/ISBN: 0002-9513 PMID: 1322039 Document Number: 393689
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.