title: Claudin-2-dependent paracellular channels are dynamically gated.
abstract: 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.
authors.affiliation: Department of Pathology, The University of Chicago, Chicago, United States.
authors.forename: Christopher R
authors.identifier: http://orcid.org/0000-0002-2117-3184
authors.initials: CR
authors.lastname: Weber
authors.affiliation: Department of Pathology, The University of Chicago, Chicago, United States.
authors.forename: Guo Hua
authors.initials: GH
authors.lastname: Liang
authors.affiliation: Department of Pathology, The University of Chicago, Chicago, United States.
authors.forename: Yitang
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Pathology, The University of Chicago, Chicago, United States.
authors.forename: Sudipto
authors.initials: S
authors.lastname: Das
authors.affiliation: Department of Pathology, The University of Chicago, Chicago, United States.
authors.forename: Le
authors.initials: L
authors.lastname: Shen
authors.affiliation: Division of Nephrology and Hypertension, University of Kansas Medical Center, Kansas City, United States.|Kidney Institute, University of Kansas Medical Center, Kansas City, United States.
authors.forename: Alan S L
authors.initials: AS
authors.lastname: Yu
authors.affiliation: Department of Pharmacological and Physiological Sciences, The University of Chicago, Chicago, United States.
authors.forename: Deborah J
authors.initials: DJ
authors.lastname: Nelson
authors.affiliation: Department of Pathology, The University of Chicago, Chicago, United States.|Departments of Pathology and Medicine (GI), Brigham and Women's Hospital and Harvard Medical School, Boston, United States.
authors.forename: Jerrold R
authors.identifier: http://orcid.org/0000-0003-0627-9455
authors.initials: JR
authors.lastname: Turner
mesh_terms: D000818:Animals; D001692:Biological Transport; D002460:Cell Line; D062446:Claudin-2 / Q000378:metabolism*; D004285:Dogs; D004847:Epithelial Cells / Q000502:physiology*; D006801:Humans; D018408:Patch-Clamp Techniques; D019108:Tight Junctions / Q000378:metabolism*
chemical_list: D062446:Claudin-2
keywords: barrier function; biophysics; cell biology; epithelium; human; intestine; ion channel; patch clamp; structural biology; tight junction