Cloning of a bovine renal epithelial Na+ channel subunit.

Academic Article

Abstract

  • 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.
  • Published In

    Keywords

  • Amino Acid Sequence, Animals, Antisense Elements (Genetics), Base Sequence, Blotting, Northern, Cattle, Cloning, Molecular, Epithelium, Humans, Immunoblotting, Isomerism, Kidney, Molecular Probes, Molecular Sequence Data, Oocytes, Protein Biosynthesis, Rats, Sequence Homology, Amino Acid, Sodium Channels, Xenopus laevis
  • Digital Object Identifier (doi)

    Author List

  • Fuller CM; Awayda MS; Arrate MP; Bradford AL; Morris RG; Canessa CM; Rossier BC; Benos DJ
  • Start Page

  • C641
  • End Page

  • C654
  • Volume

  • 269
  • Issue

  • 3 Pt 1