Abstract
Ca2+-activated K+ channels play an important role in Ca2+ signal transduction and may be regulated by mechanisms other than a direct effect of Ca2+. Inside-out patches of the apical membrane of confluent transformed rabbit cortical collecting duct cells cultured on collagen were subjected to patch clamp analysis. Two types of K+ channel, of medium and high conductance, were observed. The latter channel was characterized by a K+/Na+ permeability ratio of 10, an inwardly rectified current, a conductance of 80 pS at 0 mV, and an open probability dependent on both voltage and Ca2+. Guanosine 5′-triphosphate (GTP) but not a guanosine 5′-diphosphate (GDP) analogue, adenosine 5′-triphosphate (ATP), cytidine 5′-triphosphate (CTP), or inosine 5′-triphosphate (ITP), inhibited the activity of this Ca2+-activated K+ channel. The inhibitory effect of GTP was dose dependent, with a 50% inhibitory concentration of 10−5 m in the absence of Mg2+. In the presence of Mg2+ (1 mm), which is required for the binding of GTP to G proteins, the 50% inhibitory concentration decreased to 3×10−12 m. Pertussis toxin or cholera toxin (each at 10 ng/ml) did not prevent the inhibitory effect of GTP. After removal of GTP from the medium bathing an inhibited channel, subsequent application of Ca2+ failed to activate the channel. Ca2+-activated K+ channels of smooth muscle cells and proximal tubule cells did not respond to GTP. Thus, the Ca2+-activated K+ channel in the apical membrane of collecting duct cells is inhibited by GTP, which appears to exert its effect via a G protein that is insensitive to both cholera and pertussis toxins.
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Dietl, P., Kizer, N., Stanton, B.A. (1992). Conductive properties of a rabbit cortical collecting duct cell line: regulation by isoproterenol. Am. J, Physiol 262:F578–F582
Ercolani, L., Stow, J.L., Boyle, J.F., Holtzman, E.J., Lin, H., Grove, J.R., Ausiello, D.A. (1990). Membrane localization of the pertussis toxin-sensitive G-protein subunits αi-2 and αi-3 and expression of a metallothionein-αi-2 fusion gene in LLC-PK1 cells. Proc. Natl. Acad. Sci. USA 87:4637–4639
Fejes-Toth, G., Naray-Fejes-Toth, A. (1992). Differentiation of renal β-intercalated cells to α-intercalated and principal cells in culture. Proc. Natl. Acad. Sci USA 89:5487–5491
Geibel, J., Zweifach, A., White, S., Wang, W.H., Giebisch, G. (1990). K+ channels of the mammalian collecting duct. Renal Physiol. Biochem. 13:59–69
Guggino, S.E., Suarez-Isla, B.A., Guggino, W.B., Sacktor, B. (1985). Forskolin and antidiuretic hormone stimulate a calcium activated potassium channel in cultured kidney cells. Am. J. Physiol. 249:F448–F455
Hescheler, J., Rosenthal, W., Trautwein, W., Schultz, G. (1990). Receptor-ion channel coupling through G proteins. In: G Proteins. R. Iyenger, L. Birnbaumer, editors. pp. 384–403. Academic, SanDiego
Hunter, M., Lopes, A.G., Boulpaep, E., Giebisch, G. (1986). Regulation of single potassium ion channels from apical membrane of rabbit collecting tubule. Am. J. Physiol. 251:F725–F733
Kawahara, K. Hunter, M., Giebisch, G. (1987). Potassium channels in Necturus proximal tubule. Am. J. Physiol. 251:F488–F494
Kawahara, K., Ogawa, A., Suzuki, M. (1991). Hypoosmotic activation of Ca-activated K channels in cultured rabbit kidney tubule cells. Am. J. Physiol. 260:F27–F33
Klaerke, D.A., Jørgensen, P.L. 1988. Role of Ca2+-activated K+ channels in regulation of NaCl reabsorption in thick ascending limb of Henle's loop. Comp. Biochem. Physiol. A 90:757–765
Kume, H., Takai, A., Tokuno, H., Tomita, T. 1989. Regulation of Ca2+-dependent K+-channel activity in tracheal myocytes by phosphorylation. Nature 341:152–154
Light, D.B., Ausiello, D.A., Stanton, B.A. 1989. Guanine nucleotide-binding protein, alpha i-3, directly activates a cation channel in rat renal inner medullary collecting duct cells. J. Clin. Invest. 84:352–356
Light, D.B., Schwiebert, E.M., Karlson, K.H., Stanton, B.A. 1989. Atrial natriuretic peptide inhibits a cation channel in renal inner medullary collecting duct cells. Science 243:383–385
Light, D.B., Corbin, J.D., Stanton, B.A. 1990. Dual ion-channel regulation by cyclic GMP and cyclic GMP-dependent protein kinase. Nature 344:336–339
Mattera, R., Yatani, A., Kirsch, G.E., Graf, R., Okabe, K., Olate, J., Codina, J., Brown, A.M., Birnbaumer, L. 1989. Recombinant alpha i-3 subunit of G protein activates Gk-gated K+ channels. J. Biol. Chem. 264:465–471
McCann, J.D., Matsuda, J., Garcia, M., Kaczorowski, G., Welsh, M.J. 1990. Basolateral K+ channels in airway epithelia. I. 1990. Regulation by Ca2+ and block by charybdotoxin. Am. J. Physiol. 258:L334–L342
Montrose, R.C., Guggino, W.B. 1990. Cell volume regulation in the nephron. Annu. Rev. Physiol. 52:761–772
Rane, S.G. 1991. A Ca2+-activated K+ current in ras-transformed fibroblast is absent from nontransformed cells. Am. J. Physiol. 260:C104–C112
Sambrook, J., Fritsch, E.F., Maniatis, T. 1989. Molecular Cloning. A Laboratory Manual. pp. 1.25–1.33. Cold Spring Harbor Laboratory, New York
Sakmann, B., Neher, E. 1988. Single-Channel Recording. pp. 237–250. Plenum, New York.
Schuster, V.L., Fejes-Toth, G., Naray-Fejes-Toth, A., Gluck, S. 1991. Colocalization of H+-ATPase and band 3 anion exchanger in rabbit collecting duct intercalated cells. Am. J. Physiol. 260:F506–F517
Stow, J.L., Sabolic, I., Brown, D. 1991. Heterogeneous localization of G protein α-subunits in rat kidney. Am. J. Physiol. 261: F831–F840
Suzuki, M., Caparelli, A., Jo, O.D., Kawaguchi, Y., Ogura, Y., Miyahara, T., Yanagawa, N. 1988. Phosphate transport in the in vitro cultured rabbit proximal convoluted and straight tubules. Kidney. Int. 34:268–272
Suzuki, M., Morita, T., Hanaoka, K., Kawaguchi, Y., Sakai, O. 1991. A Cl channel activated by parathyroid hormone in rabbit renal proximal tubule cells. J. Clin. Invest. 88:735–742
Suzuki, M., Morita, T., Hasegawa, H., Miyazaki, K., Ikeda, M., Hanaoka, K., Watabe, K., Kawaguchi, Y., Sakai, O. 1992. Transformed cloned cells from isolated tubules (Proximal tubules) Jikeikai. Med. J. 39:119–126
Suzuki, M., Morita, T., Kawaguchi, Y., Kurihara, S., Sakai, O. 1991. Vitamin D metabolites increase cytoplasmic free calcium concentration in cultured rabbit proximal straight tubule cells. Am. J. Physiol. 260:F757–F763
Vaca, L., Schilling, W.P., Kunze, D.L. 1992. G-protein-mediated regulation of a Ca(2+)-dependent K+ channel in cultured vascular endothelial cells. Pfluegers Arch. 422:66–74
Volkl, H., Paulmichl, M., Lang, F. 1988. Cell volume regulation in renal cortical cells. Renal Physiol. Biochem. 11:158–173
Yatani, A., Cadina, J., Brown, A.M. 1990. G-protein mediated effects on ionic channels. In: G. Proteins, R. Iyenger, L. Birnbaumer, editors. pp. 243–261. Academic, San Diego
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Suzuki, M., Takahashi, K. & Sakai, O. Regulation by GTP of a Ca2+-activated K+ channel in the apical membrane of rabbit cortical collecting duct cells. J. Membarin Biol. 141, 43–50 (1994). https://doi.org/10.1007/BF00232872
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DOI: https://doi.org/10.1007/BF00232872