title: Conceptual barriers to understanding physical barriers.
abstract: The members of the large family of claudin proteins regulate ion and water flux across the tight junction. Many claudins, e.g. claudins 2 and 15, accomplish this by forming size- and charge-selective paracellular channels. Claudins also appear to be essential for genesis of tight junction strands and recruitment of other proteins to these sites. What is less clear is whether claudins form the paracellular seal. While this seal is defective when claudins are disrupted, some results, including ultrastructural and biochemical data, suggest that lipid structures are an important component of tight junction strands and may be responsible for the paracellular seal. This review highlights current understanding of claudin contributions to barrier function and tight junction structure and suggests a model by which claudins and other tight junction proteins can drive assembly and stabilization of a lipid-based strand structure.
authors.affiliation: Department of Pathology, The University of Chicago, United States.
authors.forename: Amulya
authors.initials: A
authors.lastname: Lingaraju
authors.affiliation: Department of Pathology, The University of Chicago, United States.
authors.forename: Tiha M
authors.initials: TM
authors.lastname: Long
authors.affiliation: Department of Pathology, The University of Chicago, United States.
authors.forename: Yitang
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Advanced Electron Microscopy Facility, Office of Shared Research Facilities, The University of Chicago, United States.
authors.forename: Jotham R
authors.initials: JR
authors.lastname: Austin
authors.affiliation: Department of Pathology, The University of Chicago, United States. Electronic address: jturner@bsd.uchicago.edu.
authors.forename: Jerrold R
authors.initials: JR
authors.lastname: Turner
mesh_terms: D000818:Animals; D057167:Claudins / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D007473:Ion Channels / Q000378:metabolism; D008055:Lipids / Q000737:chemistry; D008954:Models, Biological; D010539:Permeability; D019108:Tight Junctions / Q000737:chemistry / Q000648:ultrastructure
chemical_list: D057167:Claudins; D007473:Ion Channels; D008055:Lipids
keywords: Barrier; Claudin; Lipid; Membrane microdomain; Tight junction