Abstract
cAMP-mediated stimulation of Cl- secretion in the human intestinal cell line T84 is accompanied by significant remodeling of F-actin, and both the secretory and cytoskeletal responses may be largely ablated by previous cell loading with phalloidin derivatives, reagents that prevent dynamic reordering of microfilaments (1991. J. Clin. Invest. 87:1903-1909). In this study, we examined the effect of phalloidin loading on the cAMP-elicited activity of the individual membrane-associated transport proteins involved in electrogenic Cl- secretion. Efflux of 125I and 86Rb was used to assay forskolin-stimulated Cl- and K+ conductances, respectively, and no inhibitory effect of phalloidin could be detected. Na+/K(+)-ATPase pump activity, assessed as bumetanide-insensitive 86Rb uptake and the ability of monolayers to generate a Na+ absorptive current in response to apical addition of a Na+ ionophore, was not different between control and phalloidin-loaded monolayers. Forskolin was found to stimulate Na+/K+/2Cl- cotransport (bumetanide-sensitive 86Rb uptake) in time-dependent fashion. In the absence of any agonist, cotransporter activity was markedly decreased in phalloidin-loaded monolayers. Furthermore, under phalloidin-loaded conditions, the forskolin-elicited increase in bumetanide-sensitive 86Rb uptake was markedly attenuated. These findings suggest that cAMP-induced activity of Cl- channels, K+ channels, and the Na+/K(+)-ATPase are not influenced by F-actin stabilization. However, cAMP-induced activation of the Na+/K+/2Cl- cotransporter appears to be microfilament-dependent, and ablation of this event is likely to account for the inhibition of cAMP-elicited Cl- secretion seen in the phalloidin-loaded state. Such findings suggest that Na+/K+/2Cl- cotransporter is functionally linked to the cytoskeleton and is a regulated site of cAMP-elicited electrogenic Cl- secretion.
Full text
PDFImages in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Bennett V. Proteins involved in membrane--cytoskeleton association in human erythrocytes: spectrin, ankyrin, and band 3. Methods Enzymol. 1983;96:313–324. doi: 10.1016/s0076-6879(83)96029-9. [DOI] [PubMed] [Google Scholar]
- Breitwieser G. E., Altamirano A. A., Russell J. M. Osmotic stimulation of Na(+)-K(+)-Cl- cotransport in squid giant axon is [Cl-]i dependent. Am J Physiol. 1990 Apr;258(4 Pt 1):C749–C753. doi: 10.1152/ajpcell.1990.258.4.C749. [DOI] [PubMed] [Google Scholar]
- Cantiello H. F., Stow J. L., Prat A. G., Ausiello D. A. Actin filaments regulate epithelial Na+ channel activity. Am J Physiol. 1991 Nov;261(5 Pt 1):C882–C888. doi: 10.1152/ajpcell.1991.261.5.C882. [DOI] [PubMed] [Google Scholar]
- Dawson D. C., Richards N. W. Basolateral K conductance: role in regulation of NaCl absorption and secretion. Am J Physiol. 1990 Aug;259(2 Pt 1):C181–C195. doi: 10.1152/ajpcell.1990.259.2.C181. [DOI] [PubMed] [Google Scholar]
- Dharmsathaphorn K., Madara J. L. Established intestinal cell lines as model systems for electrolyte transport studies. Methods Enzymol. 1990;192:354–389. doi: 10.1016/0076-6879(90)92082-o. [DOI] [PubMed] [Google Scholar]
- Dharmsathaphorn K., McRoberts J. A., Mandel K. G., Tisdale L. D., Masui H. A human colonic tumor cell line that maintains vectorial electrolyte transport. Am J Physiol. 1984 Feb;246(2 Pt 1):G204–G208. doi: 10.1152/ajpgi.1984.246.2.G204. [DOI] [PubMed] [Google Scholar]
- Duffey M. E., Hainau B., Ho S., Bentzel C. J. Regulation of epithelial tight junction permeability by cyclic AMP. Nature. 1981 Dec 3;294(5840):451–453. doi: 10.1038/294451a0. [DOI] [PubMed] [Google Scholar]
- Haas M., Forbush B., 3rd Photolabeling of a 150-kDa (Na + K + Cl) cotransport protein from dog kidney with a bumetanide analogue. Am J Physiol. 1987 Aug;253(2 Pt 1):C243–C252. doi: 10.1152/ajpcell.1987.253.2.C243. [DOI] [PubMed] [Google Scholar]
- Haas M., Forbush B., 3rd [3H]bumetanide binding to duck red cells. Correlation with inhibition of (Na + K + 2Cl) co-transport. J Biol Chem. 1986 Jun 25;261(18):8434–8441. [PubMed] [Google Scholar]
- Haas M., Johnson L. G., Boucher R. C. Regulation of Na-K-Cl cotransport in cultured canine airway epithelia: a [3H]bumetanide binding study. Am J Physiol. 1990 Oct;259(4 Pt 1):C557–C569. doi: 10.1152/ajpcell.1990.259.4.C557. [DOI] [PubMed] [Google Scholar]
- Halm D. R., Rechkemmer G. R., Schoumacher R. A., Frizzell R. A. Apical membrane chloride channels in a colonic cell line activated by secretory agonists. Am J Physiol. 1988 Apr;254(4 Pt 1):C505–C511. doi: 10.1152/ajpcell.1988.254.4.C505. [DOI] [PubMed] [Google Scholar]
- Hardy M. A., DiBona D. R. Microfilaments and the hydrosmotic action of vasopressin in toad urinary bladder. Am J Physiol. 1982 Sep;243(3):C200–C204. doi: 10.1152/ajpcell.1982.243.3.C200. [DOI] [PubMed] [Google Scholar]
- Kim H. D., Tsai Y. S., Franklin C. C., Turner J. T. Characterization of Na+/K+/Cl- cotransport in cultured HT29 human colonic adenocarcinoma cells. Biochim Biophys Acta. 1988 Dec 22;946(2):397–404. doi: 10.1016/0005-2736(88)90415-4. [DOI] [PubMed] [Google Scholar]
- Kirk K. L., Halm D. R., Dawson D. C. Active sodium transport by turtle colon via an electrogenic Na-K exchange pump. Nature. 1980 Sep 18;287(5779):237–239. doi: 10.1038/287237a0. [DOI] [PubMed] [Google Scholar]
- Madara J. L., Stafford J., Barenberg D., Carlson S. Functional coupling of tight junctions and microfilaments in T84 monolayers. Am J Physiol. 1988 Mar;254(3 Pt 1):G416–G423. doi: 10.1152/ajpgi.1988.254.3.G416. [DOI] [PubMed] [Google Scholar]
- Mandel K. G., Dharmsathaphorn K., McRoberts J. A. Characterization of a cyclic AMP-activated Cl-transport pathway in the apical membrane of a human colonic epithelial cell line. J Biol Chem. 1986 Jan 15;261(2):704–712. [PubMed] [Google Scholar]
- McRoberts J. A., Beuerlein G., Dharmsathaphorn K. Cyclic AMP and Ca2+-activated K+ transport in a human colonic epithelial cell line. J Biol Chem. 1985 Nov 15;260(26):14163–14172. [PubMed] [Google Scholar]
- McRoberts J. A., Erlinger S., Rindler M. J., Saier M. H., Jr Furosemide-sensitive salt transport in the Madin-Darby canine kidney cell line. Evidence for the cotransport of Na+, K+, and Cl-. J Biol Chem. 1982 Mar 10;257(5):2260–2266. [PubMed] [Google Scholar]
- Molitoris B. A., Nelson W. J. Alterations in the establishment and maintenance of epithelial cell polarity as a basis for disease processes. J Clin Invest. 1990 Jan;85(1):3–9. doi: 10.1172/JCI114427. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nash S., Parkos C., Nusrat A., Delp C., Madara J. L. In vitro model of intestinal crypt abscess. A novel neutrophil-derived secretagogue activity. J Clin Invest. 1991 Apr;87(4):1474–1477. doi: 10.1172/JCI115156. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nelson W. J., Hammerton R. W. A membrane-cytoskeletal complex containing Na+,K+-ATPase, ankyrin, and fodrin in Madin-Darby canine kidney (MDCK) cells: implications for the biogenesis of epithelial cell polarity. J Cell Biol. 1989 Mar;108(3):893–902. doi: 10.1083/jcb.108.3.893. [DOI] [PMC free article] [PubMed] [Google Scholar]
- O'Donnell M. E. [3H]bumetanide binding in vascular endothelial cells. Quantitation of Na-K-Cl cotransporters. J Biol Chem. 1989 Dec 5;264(34):20326–20330. [PubMed] [Google Scholar]
- O'Grady S. M., Palfrey H. C., Field M. Characteristics and functions of Na-K-Cl cotransport in epithelial tissues. Am J Physiol. 1987 Aug;253(2 Pt 1):C177–C192. doi: 10.1152/ajpcell.1987.253.2.C177. [DOI] [PubMed] [Google Scholar]
- O'Neill W. C., Klein J. D. Regulation of vascular endothelial cell volume by Na-K-2Cl cotransport. Am J Physiol. 1992 Feb;262(2 Pt 1):C436–C444. doi: 10.1152/ajpcell.1992.262.2.C436. [DOI] [PubMed] [Google Scholar]
- Owen N. E., Prastein M. L. Na/K/Cl cotransport in cultured human fibroblasts. J Biol Chem. 1985 Feb 10;260(3):1445–1451. [PubMed] [Google Scholar]
- Paris S., Pouysségur J. Growth factors activate the bumetanide-sensitive Na+/K+/Cl-cotransport in hamster fibroblasts. J Biol Chem. 1986 May 15;261(14):6177–6183. [PubMed] [Google Scholar]
- Shapiro M., Matthews J., Hecht G., Delp C., Madara J. L. Stabilization of F-actin prevents cAMP-elicited Cl- secretion in T84 cells. J Clin Invest. 1991 Jun;87(6):1903–1909. doi: 10.1172/JCI115215. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Venglarik C. J., Bridges R. J., Frizzell R. A. A simple assay for agonist-regulated Cl and K conductances in salt-secreting epithelial cells. Am J Physiol. 1990 Aug;259(2 Pt 1):C358–C364. doi: 10.1152/ajpcell.1990.259.2.C358. [DOI] [PubMed] [Google Scholar]