AJP - Cell Physiology, Vol 269, Issue 3 C641-C654, Copyright © 1995 by American Physiological Society

ARTICLES

Cloning of a bovine renal epithelial Na+ channel subunit

C. M. Fuller, M. S. Awayda, M. P. Arrate, A. L. Bradford, R. G. Morris, C. M. Canessa, B. C. Rossier and D. J. Benos
Department of Physiology and Biophysics, University of Alabama at Birmingham 35294, USA.

A bovine homologue of the rat and human epithelial Na+ channel subunits, alpha-rENaC and alpha-hENaC, was cloned. The cDNA clone, termed alpha-bENaC, was isolated from a bovine renal papillary collecting duct cDNA expression library. The bovine cDNA is 3,584 base pairs (bp) long, has an open reading frame of 2,094 bp encoding a 697-amino acid protein, and is 75-85% homologous to its rat and human counterparts. In vitro translation of the transcribed cRNA yields an 80-kDa polypeptide and one at 92 kDa in the presence of pancreatic microsomes. The clone exhibits consensus sequences for N-linked glycosylation and for phosphorylation by protein kinase C, but not for protein kinase A. After expression in Xenopus laevis oocytes, a small amiloride-sensitive Na+ conductance that exhibited inward rectification and a reversal potential greater than +30 mV, consistent with the predicted equilibrium potential for Na+, was identified. The expressed alpha-bENaC-associated Na+ current was not responsive to elevations in adenosine 3',5'-cyclic monophosphate but could be stimulated by phorbol 12-myristate 13-acetate, an activator of protein kinase C. alpha-bENaC also formed amiloride-sensitive chimeric channels when coexpressed with the rat beta- and gamma-ENaC subunits in Xenopus oocytes. alpha-bENaC therefore represents a novel isoform of a growing family of epithelial Na+ channels.

This article has been cited by other articles:

				U. S. Rao, R. E. Steimle, and P. Balachandran Activation of Large Conductance Sodium Channels upon Expression of Amiloride-sensitive Sodium Channel in Sf9 Insect Cells J. Biol. Chem., February 8, 2002; 277(7): 4900 - 4905. [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]

				Y. J. Ahn, D. R. Brooker, F. Kosari, B. J. Harte, J. Li, S. A. Mackler, and T. R. Kleyman Cloning and functional expression of the mouse epithelial sodium channel Am J Physiol Renal Physiol, July 1, 1999; 277(1): F121 - F129. [Abstract] [Full Text] [PDF]

				S. Coscoy, J. R. de Weille, E. Lingueglia, and M. Lazdunski The Pre-transmembrane 1 Domain of Acid-sensing Ion Channels Participates in the Ion Pore J. Biol. Chem., April 9, 1999; 274(15): 10129 - 10132. [Abstract] [Full Text] [PDF]

				J. K. Bubien, T. Cornwell, A. L. Bradford, C. M. Fuller, M. D. DuVall, and D. J. Benos alpha -Adrenergic receptors regulate human lymphocyte amiloride-sensitive sodium channels Am J Physiol Cell Physiol, September 1, 1998; 275(3): C702 - C710. [Abstract] [Full Text] [PDF]

				C. P. Thomas, S. Auerbach, J. B. Stokes, and K. A. Volk 5' Heterogeneity in epithelial sodium channel alpha -subunit mRNA leads to distinct NH2-terminal variant proteins Am J Physiol Cell Physiol, May 1, 1998; 274(5): C1312 - C1323. [Abstract] [Full Text] [PDF]

				H.-L. Ji, M. D. Duvall, H. K. Patton, C. L. Satterfield, C. M. Fuller, and D. J. Benos Functional expression of a truncated Ca2+-activated Cl- channel and activation by phorbol ester Am J Physiol Cell Physiol, February 1, 1998; 274(2): C455 - C464. [Abstract] [Full Text] [PDF]

				Y. Cui, Y. R. Su, M. Rutkowski, M. Reif, A. G. Menon, and R. Y. K. Pun Loss of protein kinase C inhibition in the beta -T594M variant of the amiloride-sensitive Na+ channel PNAS, September 2, 1997; 94(18): 9962 - 9966. [Abstract] [Full Text] [PDF]

				I. I. Ismailov, T. Kieber-Emmons, C. Lin, B. K. Berdiev, V. Gh. Shlyonsky, H. K. Patton, C. M. Fuller, R. Worrell, J. B. Zuckerman, W. Sun, et al. Identification of an Amiloride Binding Domain within the alpha -Subunit of the Epithelial Na+ Channel J. Biol. Chem., August 22, 1997; 272(34): 21075 - 21083. [Abstract] [Full Text] [PDF]

				C. M. Fuller, I. I. Ismailov, B. K. Berdiev, VadimG. Shlyonsky, and DaleJ. Benos Kinetic Interconversion of Rat and Bovine Homologs of the alpha Subunit of an Amiloride-sensitive Na+ Channel by C-terminal Truncation of the Bovine Subunit J. Biol. Chem., October 25, 1996; 271(43): 26602 - 26608. [Abstract] [Full Text] [PDF]