Regions in the carboxy terminus of α-bENaC involved in gating and functional effects of actin

Susan J. Copeland, Bakhrom K. Berdiev, Hong Long Ji, Jason Lockhart, Suzanne Parker, Catherine M. Fuller, Dale J. Benos

Research output: Contribution to journalArticle

40 Citations (Scopus)

Abstract

Gating differences occur between the α-subunits of the bovine and rat clones of an amiloride-sensitive epithelial Na+ channel (ENaC). Deletion of the carboxy terminus of bovine α-ENaC (α-bENaC) at R567 converted the gating properties to that of rat α-ENaC (α-rENaC). The equivalent truncation in α-rENaC was without effect on the gating of the rat homologue. The addition of actin to ENaC channels composed of either α-rENaC or α-bENaC alone produced a two fold reduction in conductance and an increase in open probability. Neither α-rENaC (R613X) nor α-bENaC (R567X) was responsive to actin. Using a chimera consisting of αrENaC1-615 and α-bENaC570-650, we examined several different carboxy-terminal truncation mutants plus and minus actin. When incorporated into planar bilayers, the gating pattern of this construct was identical to wild-type (wt) α-bENaC. Premature stop mutations proximal to E685X produced channels with gating patterns like α-rENaC. Actin had no effect on the E631X truncation, whereas more distal truncations all interacted with actin, as did wt α-bENaC. Key findings were confirmed using channels expressed in Xenopus oocytes and studied by cell-attached patch-clamp recording. Our results suggest that the site of actin regulation at the carboxy terminus of the chimera is located between residues 631 and 644.

Original languageEnglish
JournalAmerican Journal of Physiology - Cell Physiology
Volume281
Issue number1 50-1
Publication statusPublished - 2001
Externally publishedYes

Fingerprint

Actins
Epithelial Sodium Channels
Rats
Amiloride
Clamping devices
Xenopus
Oocytes
Clone Cells
Mutation

Keywords

  • α-subunit of bovine epithelial sodium channel
  • Amiloride
  • Ion channels
  • Oocytes
  • Patch clamp
  • Planar lipid bilayers

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Cell Biology
  • Physiology
  • Physiology (medical)

Cite this

Copeland, S. J., Berdiev, B. K., Ji, H. L., Lockhart, J., Parker, S., Fuller, C. M., & Benos, D. J. (2001). Regions in the carboxy terminus of α-bENaC involved in gating and functional effects of actin. American Journal of Physiology - Cell Physiology, 281(1 50-1).

Regions in the carboxy terminus of α-bENaC involved in gating and functional effects of actin. / Copeland, Susan J.; Berdiev, Bakhrom K.; Ji, Hong Long; Lockhart, Jason; Parker, Suzanne; Fuller, Catherine M.; Benos, Dale J.

In: American Journal of Physiology - Cell Physiology, Vol. 281, No. 1 50-1, 2001.

Research output: Contribution to journalArticle

Copeland, SJ, Berdiev, BK, Ji, HL, Lockhart, J, Parker, S, Fuller, CM & Benos, DJ 2001, 'Regions in the carboxy terminus of α-bENaC involved in gating and functional effects of actin', American Journal of Physiology - Cell Physiology, vol. 281, no. 1 50-1.
Copeland, Susan J. ; Berdiev, Bakhrom K. ; Ji, Hong Long ; Lockhart, Jason ; Parker, Suzanne ; Fuller, Catherine M. ; Benos, Dale J. / Regions in the carboxy terminus of α-bENaC involved in gating and functional effects of actin. In: American Journal of Physiology - Cell Physiology. 2001 ; Vol. 281, No. 1 50-1.
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