Claudin-2-dependent paracellular channels are dynamically gated

• Published in: eLife Vol. 4; p. e09906
• Main Authors: Weber, Christopher R, Liang, Guo Hua, Wang, Yitang, Das, Sudipto, Shen, Le, Yu, Alan S L, Nelson, Deborah J, Turner, Jerrold R
• Format: Journal Article
• Language: English
• Published: England eLife Science Publications, Ltd 14.11.2015; eLife Sciences Publications Ltd; eLife Sciences Publications, Ltd
• Subjects: Analysis; Animals; barrier function; Biological Transport; Biophysics and Structural Biology; Cell Biology; Cell Line; Chronic kidney failure; Claudin-2 - metabolism; Dogs; Epithelial Cells - physiology; epithelium; Gastrointestinal diseases; Humans; intestine; ion channel; Monomolecular films; patch clamp; Patch-Clamp Techniques; tight junction; Tight Junctions - metabolism; patch clamp; cell biology; intestine; ion channel; epithelium; structural biology; biophysics; human; barrier function; tight junction
• ISSN: 2050-084X; 2050-084X
• DOI: 10.7554/elife.09906

Intercellular tight junctions form selectively permeable barriers that seal the paracellular space. Trans-tight junction flux has been measured across large epithelial surfaces, but conductance across individual channels has never been measured. We report a novel trans-tight junction patch clamp technique that detects flux across individual claudin-2 channels within the tight junction of cultured canine renal tubule or human intestinal epithelial monolayers. In both cells, claudin-2 channels display conductances of ~90 pS. The channels are gated, strictly dependent on claudin-2 expression, and display size- and charge-selectivity typical of claudin-2. Kinetic analyses indicate one open and two distinct closed states. Conductance is symmetrical and reversible, characteristic of a passive, paracellular process, and blocked by reduced temperature or site-directed mutagenesis and chemical derivatization of the claudin-2 pore. We conclude that claudin-2 forms gated paracellular channels and speculate that modulation of tight junction channel gating kinetics may be an unappreciated mechanism of barrier regulation.