Related Experiment Video
Updated: Aug 22, 2026

Implementing Patch Clamp and Live Fluorescence Microscopy to Monitor Functional Properties of Freshly Isolated PKD Epithelium
Published on: September 1, 2015
Control of epithelial ion transport by Cl- and PDZ proteins
R Schreiber1, A Boucherot, B Mürle
1Institut für Physiologie, Universität Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany.
Abstract:
Inhibition of epithelial Na+ channels (ENaC) by the cystic fibrosis transmembrane conductance regulator (CFTR) has been demonstrated previously. Recent studies suggested a role of cytosolic Cl- for the interaction of CFTR with ENaC, when studied in Xenopus oocytes. In the present study we demonstrate that the Na+ / H+ -exchanger regulator factor (NHERF) controls expression of CFTR in mouse collecting duct cells. Inhibition of NHERF largely attenuates CFTR expression, which is paralleled by enhanced Ca(2+) -dependent Cl- secretion and augmented Na+ absorption by the ENaC. It is further demonstrated that epithelial Na+ absorption and ENaC are inhibited by cytosolic Cl- and that stimulation by secretagogues enhances the intracellular Cl- concentration. Thus, the data provide a clue to the question, how epithelial cells can operate as both absorptive and secretory units: Increase in intracellular Cl- during activation of secretion will inhibit ENaC and switch epithelial transport from salt absorption to Cl- secretion.
More Related Videos
Related Concept Videos
Tight Junctions
Reabsorption and Secretion in the DCT and Collecting Duct
The distal part of the DCT, along with the...
Transcellular Transport of Solutes
ATP Driven Pumps III: V-type Pumps
The peripheral or cytosolic V1 domain with eight subunits is involved in ATP hydrolysis. The integral or transmembrane V0 domain containing at least five subunits...
Reabsorption and Secretion in the Loop of Henle
Reabsorption and Secretion in the PCT
Transport mechanisms involving sodium ions (Na+) contribute significantly to solute reabsorption. These mechanisms include symport and antiport processes.
A key example is the...

