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Biochem Biophys Res Commun. 2008 Dec 12;377(2):521-525. doi: 10.1016/j.bbrc.2008.10.014. Epub 2008 Oct 14.

Regulation of ENaC expression at the cell surface by Rab11.

Author information

1
Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI 53226, USA.
2
Biotechnology & Bioengineering Center, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI 53226, USA.
3
INSERM, U773, Centre de Recherche Biomedicale Bichat-Beaujon CRB3, Universite Paris, Paris, France.
4
Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI 53226, USA; Biotechnology & Bioengineering Center, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI 53226, USA.
5
Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI 53226, USA; Kidney Disease Center, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI 53226, USA. Electronic address: Staruschenko@mcw.edu.

Abstract

The epithelial Na(+) channel (ENaC) is an essential channel responsible for Na(+) reabsorption. Coexpression of Rab11a and Rab3a small G proteins with ENaC results in a significant increase in channel activity. In contrast, coexpression of Rab5, Rab27a, and Arf-1 had no effect or slightly decreased ENaC activity. Inhibition of MEK with PD98059, Rho-kinase with Y27632 or PI3-kinase with LY294002 had no effect on ENaC activity in Rab11a-transfected CHO cells. Fluorescence imaging methods demonstrate that Rab11a colocalized with ENaC. Rab11a increases ENaC activity in an additive manner with dominant-negative dynamin, which is a GTPase responsible for endocytosis. Brefeldin A, an inhibitor of intracellular protein translocation, blocked the stimulatory action of Rab11a on ENaC activity. We conclude that ENaC channels, present on the apical plasma membrane, are being exchanged with channels from the intracellular pool in a Rab11-dependent manner.

PMID:
18926797
PMCID:
PMC2612579
DOI:
10.1016/j.bbrc.2008.10.014
[Indexed for MEDLINE]
Free PMC Article

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