Weber, Christopher RLiang, Guo HuaWang, YitangDas, SudiptoShen, LeYu, Alan S LNelson, Deborah JTurner, Jerrold2016-03-012015Weber, Christopher R, Guo Hua Liang, Yitang Wang, Sudipto Das, Le Shen, Alan S L Yu, Deborah J Nelson, and Jerrold R Turner. 2015. “Claudin-2-dependent paracellular channels are dynamically gated.” eLife 4 (1): e09906. doi:10.7554/eLife.09906. http://dx.doi.org/10.7554/eLife.09906.2050-084Xhttp://nrs.harvard.edu/urn-3:HUL.InstRepos:25658337Intercellular 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. DOI: http://dx.doi.org/10.7554/eLife.09906.001en-UStight junctionepitheliumion channelpatch clampbarrier functionintestineHumanOtherJournal Article2016-03-0110.7554/eLife.09906