Related Experiment Video
Updated: Jun 22, 2026

Functional Assessment of Intestinal Tight Junction Barrier and Ion Permeability in Native Tissue by Ussing Chamber Technique
Published on: May 26, 2021
Cysteine mutagenesis to study the structure of claudin-2 paracellular pores
1Department of Medicine, Division of Nephrology, University of Southern California Keck School of Medicine, Los Angeles, California 90089, USA. angelow@usc.edu
Abstract:
The structure and transport mechanism of paracellular pores are only poorly understood. Here we describe for the first time how the substituted cysteine accessibility method (SCAM), previously developed to study transmembrane transport, can be applied to analyze the pathway of paracellular ion permeation. Using stable transfected Madin Darby canine kidney type I cells, induced to express claudin-2, we show that paracellular cation transport can be blocked by sulfhydryl-specific methanethiosulfonate (MTS) and that SCAM can be used to identify residues that line paracellular pores.
Related Concept Videos
Cystic Fibrosis: Pathogenesis
CF is primarily caused by a genetic mutation in a chromosome 7 gene coding for the cystic fibrosis transmembrane conductance regulator (CFTR) protein. The most common gene mutation leading to CF is the ΔF508 mutation, but...
Tight Junctions

