Pflügers Archiv

, Volume 451, Issue 5, pp 631–641

Two-pore-domain potassium channels support anion secretion from human airway Calu-3 epithelial cells

Epithelial Transport

DOI: 10.1007/s00424-005-1505-4

Cite this article as:
Davis, K.A. & Cowley, E.A. Pflugers Arch - Eur J Physiol (2006) 451: 631. doi:10.1007/s00424-005-1505-4

Abstract

Potassium channels are required for the absorption and secretion of fluids and electrolytes in epithelia. Calu-3 cells possess a secretory phenotype, and are a model human airway submucosal gland serous cell. Short-circuit current (Isc) recordings from Calu-3 cells indicated that basal anion secretion was reduced by apical application of the K+ channel inhibitors bupivicaine, lidocaine, clofilium, and quinidine. Application of riluzole resulted in a large increase in Isc, inhibited by apical application of either bupivicane or the cystic fibrosis transmembrane conductance regulator (CFTR) Cl channel blocker DPC. These results suggested that one or more members of the two-pore-domain K+ (K2P) channel family could influence anion secretion. Using RT-PCR, we found that Calu-3 cells express mRNA transcripts for TASK-2 (KCNK5), TWIK-1 (KCNK1), TWIK-2 (KCNK6) and TREK-1 (KCNK2). TASK-2, TWIK-2 and TREK-1 protein were detected by Western blotting, while immunolocalization of polarized cells confirmed protein expression of TREK-1 and TWIK-2 at the plasma cell membrane. TASK-2 protein staining was localized to intracellular vesicles, located beneath the apical membrane. While the pro-secretory role of basolateral K+ channels is well established, we suggest that apically located K2Pchannels, not previously described in airway epithelial cells, also play an important role in controlling the rate of transepithelial anion secretion.

Keywords

Transepithelial anion secretion Epithelial K+ channels Cystic fibrosis Airway epithelia 

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  1. 1.Department of Physiology and BiophysicsDalhousie UniversityHalifaxCanada

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