| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Biophysical Journal 72: 1182-1192 (1997)
© 1997 the Biophysical Society
Department of Physiology and Biophysics, University of Alabama at Birmingham 35294, USA.
ABSTRACT
A family of novel epithelial Na+ channels (ENaCs) have recently been cloned from several different tissues. Three homologous subunits (alpha, beta, gamma-ENaCs) from the core conductive unit of Na(+)-selective, amiloride-sensitive channels that are found in epithelia. We here report the results of a study assessing the regulation of alpha,beta,gamma-rENaC by Ca2+ in planar lipid bilayers. Buffering of the bilayer bathing solutions to [Ca2+] < 1 nM increased single-channel open probability by fivefold. Further investigation of this phenomenon revealed that Ca2+ ions produced a voltage-dependent block, affecting open probability but not the unitary conductance of ENaC. Imposing a hydrostatic pressure gradient across bilayers containing alpha,beta,gamma-rENaC markedly reduced the sensitivity of these channels to inhibition by [Ca2+]. Conversely, in the nominal absence of Ca2+, the channels lost their sensitivity to mechanical stimulation. These results suggest that the previously observed mechanical activation of ENaCs reflects a release of the channels from block by Ca2+.
This article has been cited by other articles:
 |
|
 |
|
  H. A. Drummond, S. C. Grifoni, and N. L. Jernigan A New Trick for an Old Dogma: ENaC Proteins as Mechanotransducers in Vascular Smooth Muscle Physiology, February 1, 2008; 23(1): 23 - 31. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. A. Drummond, D. Gebremedhin, and D. R. Harder Degenerin/Epithelial Na+ Channel Proteins: Components of a Vascular Mechanosensor Hypertension, November 1, 2004; 44(5): 643 - 648. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. J. Benos Sensing Tension: Recognizing ENaC as a Stretch Sensor Hypertension, November 1, 2004; 44(5): 616 - 617. [Full Text] [PDF]
|
|
|
|
 |
|
 M. D. Carattino, S. Sheng, and T. R. Kleyman Epithelial Na+ Channels Are Activated by Laminar Shear Stress J. Biol. Chem., February 6, 2004; 279(6): 4120 - 4126. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Palmer-Densmore, C. Deachapunya, M. Kannan, and S. M. O'Grady UTP-dependent Inhibition of Na+ Absorption Requires Activation of PKC in Endometrial Epithelial Cells J. Gen. Physiol., November 25, 2002; 120(6): 897 - 906. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. M. Snyder The Epithelial Na+ Channel: Cell Surface Insertion and Retrieval in Na+ Homeostasis and Hypertension Endocr. Rev., April 1, 2002; 23(2): 258 - 275. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. K. Berdiev, T. B. Mapstone, J. M. Markert, G. Y. Gillespie, J. Lockhart, C. M. Fuller, and D. J. Benos pH Alterations "Reset" Ca2+ Sensitivity of Brain Na+ Channel 2, a Degenerin/Epithelial Na+ Ion Channel, in Planar Lipid Bilayers J. Biol. Chem., October 12, 2001; 276(42): 38755 - 38761. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. J. Copeland, B. K. Berdiev, H.-L. Ji, J. Lockhart, S. Parker, C. M. Fuller, and D. J. Benos Regions in the carboxy terminus of {alpha}-bENaC involved in gating and functional effects of actin Am J Physiol Cell Physiol, July 1, 2001; 281(1): C231 - C240. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 O. P. Hamill and B. Martinac Molecular Basis of Mechanotransduction in Living Cells Physiol Rev, April 1, 2001; 81(2): 685 - 740. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. de Baey and A. Lanzavecchia The Role of Aquaporins in Dendritic Cell Macropinocytosis J. Exp. Med., February 21, 2000; 191(4): 743 - 748. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. M. Waters, K. M. Ridge, G. Sunio, K. Venetsanou, and J. I. Sznajder Mechanical stretching of alveolar epithelial cells increases Na+-K+-ATPase activity J Appl Physiol, August 1, 1999; 87(2): 715 - 721. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. K. Bubien, D. A. Keeton, C. M. Fuller, G. Y. Gillespie, A. T. Reddy, T. B. Mapstone, and D. J. Benos Malignant human gliomas express an amiloride-sensitive Na+ conductance Am J Physiol Cell Physiol, June 1, 1999; 276(6): C1405 - C1410. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H.-L. Ji, C. M. Fuller, and D. J. Benos Osmotic pressure regulates alpha beta gamma -rENaC expressed in Xenopus oocytes Am J Physiol Cell Physiol, November 1, 1998; 275(5): C1182 - C1190. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 I. I. Ismailov, V. Gh. Shlyonsky, and D. J. Benos Streaming potential measurements in alpha beta gamma -rat epithelial Na+ channel in planar lipid bilayers PNAS, July 8, 1997; 94(14): 7651 - 7654. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H.-P. Ma, L. Li, Z.-H. Zhou, D. C. Eaton, and D. G. Warnock ATP masks stretch activation of epithelial sodium channels in A6 distal nephron cells Am J Physiol Renal Physiol, March 1, 2002; 282(3): F501 - F505. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
