NYMC Faculty Publications

Kcnj10 Is a Major Type of K+ Channel in Mouse Corneal Epithelial Cells and Plays a Role in Initiating EGFR Signaling

Author Type(s)

Faculty

DOI

10.1152/ajpcell.00040.2014

Journal Title

American Journal of Physiology. Cell Physiology

First Page

C710

Last Page

7

Document Type

Article

Publication Date

10-15-2014

Keywords

EGFR signaling, Kir4.1, Rac1, corneal epithelial cells membrane potential

Disciplines

Medicine and Health Sciences

Abstract

We used primary mouse corneal epithelial cells (pMCE) to examine the role of Kcnj10 in determining membrane K(+) conductance and cell membrane potential and in regulating EGF/TGFA release. Western blot, immunostaining, and RT-PCR detected the expression of Kcnj10 in mouse cornea. The single channel recording identified the 20-pS inwardly rectifying K(+) channels in pMCE of WT mice, but these channels were absent in Kcnj10(-/-). Moreover, the whole cell recording demonstrates that deletion of Kcnj10 largely abolished the inward K(+) currents and depolarized the cell membrane K(+) reversal potential (an index of the cell membrane potential). This suggests that Kcnj10 is a main contributor to the cell K(+) conductance and it is pivotal in generating membrane potential in cornea. Furthermore, to test the hypothesis that Kcnj10 expression plays a key role in the stimulation of growth factors release, we employed an immortalized human corneal epithelial cell line (HCE) transfected with siRNA-Kcnj10 or siRNA-control. Levels of TGFA and EGF secreted in the medium were measured by ELISA. Coimmunoprecipitation, biotinylation, and pull-down assay were used to examine the expression of EGFR and the GTP bound form of Rac1 (active Rac1). Downregulation of Kcnj10 activated Rac1 and enhanced EGF/TGFA release, which further contributed to the upregulation of EGFR phosphorylation and surface expression. We conclude that Kcnj10 is a main K(+) channel expressed in corneal epithelial cells and the inhibition of Kcnj10 resulted in depolarization, which in turn induced an EGF-like effect.

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