title: The emergence of the concept of tight junctions and physiological regulation by ouabain.
abstract: The exchange of substances between metazoan and the environment takes place across transporting epithelia that have two fundamental differentiated features: tight junctions (TJ) and apical/basolateral polarity. Usually, reviews of the structure and function of transporting epithelia follow a historical description of major biological findings, but seldom refer to the fact that it also required fundamental theoretical changes in the physics and chemistry involved. We make a brief description of the concatenation of both types of achievements, in which it becomes clear that the major source of conflicts was the enzyme Na(+),K(+)-ATPase (also referred to as "the pump"), because of its intrinsic mechanisms and its asymmetric expression on one side of epithelial cells only (polarity). This enzyme is also the receptor of the newly recognized hormone ouabain, whose chief function is to modulate cell contacts, such as TJs, several types of cell-cell contacts participating in polarization (as gauged through ciliogenesis).
authors.affiliation: Department of Physiology, Biophysics and Neurosciences, Center for Research & Advanced Studies (Cinvestav), Mexico.
authors.forename: I
authors.initials: I
authors.lastname: Larre
authors.affiliation: Department of Physiology, Biophysics and Neurosciences, Center for Research & Advanced Studies (Cinvestav), Mexico.
authors.forename: A
authors.initials: A
authors.lastname: Ponce
authors.affiliation: National Institute of Cardiology "Ignacio Chavez", Mexico.
authors.forename: M
authors.initials: M
authors.lastname: Franco
authors.affiliation: Department of Physiology, Biophysics and Neurosciences, Center for Research & Advanced Studies (Cinvestav), Mexico. Electronic address: cereijido@fisio.cinvestav.mx.
authors.forename: M
authors.initials: M
authors.lastname: Cereijido
mesh_terms: D001692:Biological Transport; D002923:Cilia / Q000378:metabolism; D062446:Claudin-2; D004847:Epithelial Cells / Q000502:physiology*; D004848:Epithelium / Q000502:physiology*; D006801:Humans; D010042:Ouabain / Q000378:metabolism*; D010539:Permeability; D000254:Sodium-Potassium-Exchanging ATPase; D019108:Tight Junctions / Q000502:physiology*
chemical_list: D062446:Claudin-2; D010042:Ouabain; D000254:Sodium-Potassium-Exchanging ATPase
keywords: Cilium; Epithelia; Na(+),K(+)-ATPase; Ouabain; Tight junction