Associated proteins and renal epithelial Na+ channel function

I. I. Ismailov, B. K. Berdiev, A. L. Bradford, M. S. Awayda, C. M. Fuller, D. J. Benos

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

The hypothesis that amiloride-sensitive Na+ channel complexes immunopurified from bovine renal papillary collecting tubules contain, as their core conduction component, an ENaC subunit, was tested by functional and immunological criteria. Disulfide bond reduction with dithiothreitol (DTT) of renal Na+ channels incorporated into planar lipid bilayers caused a reduction of single channel conductance from 40 pS to 13 pS, and uncoupled PKA regulation of this channel. The cation permeability sequence, as assessed from bi-ionic reversal potential measurements, and apparent amiloride equilibrium dissociation constant (I(i)(amil)) of the Na+ channels were unaltered by DTT treatment. Like ENaC, the DTT treated renal channel became mechanosensitive, and displayed a substantial decrease in Ki(i)(amil)) following stretch (0.44 ± 0.12 μM versus 6.9 ± 1.0 μM). Moreover, stretch activation induced a loss in the channel's ability to discriminate between monovalent cations, and even allowed Ca2+ to permeate. Polyclonal antibodies generated against a fusion protein of αbENaC recognized a 70 kDa polypeptide component of the renal Na+ channel complex. These data suggest that ENaC is present in the immunopurified renal Na+ channel protein complex, and that PKA sensitivity is conferred by other associated proteins.

Original languageEnglish
Pages (from-to)123-132
Number of pages10
JournalJournal of Membrane Biology
Volume149
Issue number2
DOIs
Publication statusPublished - 1996
Externally publishedYes

Fingerprint

Epithelial Sodium Channels
Dithiothreitol
Kidney
Amiloride
Proteins
Monovalent Cations
Lipid Bilayers
Disulfides
Cations
Permeability
Peptides
Antibodies

Keywords

  • Ion selectivity
  • Mechanosensitivity
  • Membranes
  • Planar lipid bilayers
  • Protein kinase A
  • Reduction

ASJC Scopus subject areas

  • Biophysics
  • Physiology
  • Cell Biology

Cite this

Ismailov, I. I., Berdiev, B. K., Bradford, A. L., Awayda, M. S., Fuller, C. M., & Benos, D. J. (1996). Associated proteins and renal epithelial Na+ channel function. Journal of Membrane Biology, 149(2), 123-132. https://doi.org/10.1007/s002329900013

Associated proteins and renal epithelial Na+ channel function. / Ismailov, I. I.; Berdiev, B. K.; Bradford, A. L.; Awayda, M. S.; Fuller, C. M.; Benos, D. J.

In: Journal of Membrane Biology, Vol. 149, No. 2, 1996, p. 123-132.

Research output: Contribution to journalArticle

Ismailov, II, Berdiev, BK, Bradford, AL, Awayda, MS, Fuller, CM & Benos, DJ 1996, 'Associated proteins and renal epithelial Na+ channel function', Journal of Membrane Biology, vol. 149, no. 2, pp. 123-132. https://doi.org/10.1007/s002329900013
Ismailov II, Berdiev BK, Bradford AL, Awayda MS, Fuller CM, Benos DJ. Associated proteins and renal epithelial Na+ channel function. Journal of Membrane Biology. 1996;149(2):123-132. https://doi.org/10.1007/s002329900013
Ismailov, I. I. ; Berdiev, B. K. ; Bradford, A. L. ; Awayda, M. S. ; Fuller, C. M. ; Benos, D. J. / Associated proteins and renal epithelial Na+ channel function. In: Journal of Membrane Biology. 1996 ; Vol. 149, No. 2. pp. 123-132.
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