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Regulation of murine cystic fibrosis transmembrane conductance regulator Cl- channels expressed in Chinese hamster ovary cells.
- Source :
-
The Journal of physiology [J Physiol] 1998 Nov 01; Vol. 512 ( Pt 3), pp. 751-64. - Publication Year :
- 1998
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Abstract
- 1. We investigated the effect of protein kinases and phosphatases on murine cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channels, expressed in Chinese hamster ovary (CHO) cells, using iodide efflux and the excised inside-out configuration of the patch-clamp technique. 2. The protein kinase C (PKC) activator, phorbol dibutyrate, enhanced cAMP-stimulated iodide efflux. However, PKC did not augment the single-channel activity of either human or murine CFTR Cl- channels that had previously been activated by protein kinase A. 3. Fluoride, a non-specific inhibitor of protein phosphatases, stimulated both human and murine CFTR Cl- channels. However, calyculin A, a potent inhibitor of protein phosphatases 1 and 2A, did not enhance cAMP-stimulated iodide efflux. 4. The alkaline phosphatase inhibitor, (-)-bromotetramisole augmented cAMP-stimulated iodide efflux and, by itself, stimulated a larger efflux than that evoked by cAMP agonists. However, (+)-bromotetramisole, the inactive enantiomer, had the same effect. For murine CFTR, neither enantiomer enhanced single-channel activity. In contrast, both enantiomers increased the open probability (Po) of human CFTR, suggesting that bromotetramisole may promote the opening of human CFTR. 5. As murine CFTR had a low Po and was refractory to stimulation by activators of human CFTR, we investigated whether murine CFTR may open to a subconductance state. When single-channel records were filtered at 50 Hz, a very small subconductance state of murine CFTR was observed that had a Po greater than that of human CFTR. The occupancy of this subconductance state may explain the differences in channel regulation observed between human and murine CFTR.
- Subjects :
- Algorithms
Animals
CHO Cells
Cricetinae
Electric Stimulation
Electrophysiology
Enzyme Activation drug effects
Enzyme Activation physiology
Enzyme Inhibitors pharmacology
Fluorides pharmacology
Humans
Iodides metabolism
Membrane Potentials physiology
Mice
Patch-Clamp Techniques
Phosphoprotein Phosphatases antagonists & inhibitors
Phosphoprotein Phosphatases pharmacology
Protein Kinase C metabolism
Protein Kinase Inhibitors
Protein Kinases pharmacology
Chloride Channels metabolism
Cystic Fibrosis Transmembrane Conductance Regulator metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0022-3751
- Volume :
- 512 ( Pt 3)
- Database :
- MEDLINE
- Journal :
- The Journal of physiology
- Publication Type :
- Academic Journal
- Accession number :
- 9769419
- Full Text :
- https://doi.org/10.1111/j.1469-7793.1998.751bd.x