Marcelino Cereijido

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Tight junctions, the most apical of the intercellular junctions that connect individual cells in a epithelial sheet, are thought to form a seal that restricts paracellular and intramembrane diffusion. To analyze the functioning of tight junctions, we generated stable MDCK strain 2 cell lines expressing either full-length or COOH-terminally truncated chicken(More)
Extracellular Ca2+ triggers assembly and sealing of tight junctions (TJs) in MDCK cells. These events are modulated by G-proteins, phospholipase C, protein kinase C (PKC), and calmodulin. In the present work we observed that 1,2-dioctanoylglycerol (diC8) promotes the assembly of TJ in low extracellular Ca2+, as evidenced by translocation of the(More)
Upon transferring confluent monolayers of Madin-Darby canine kidney (MDCK) cells from a low-Ca2+ medium (1-5 microM) to one with 1.8 mM Ca2+ (Ca switch), tight junctions (TJs) assemble and seal, and transepithelial electrical resistance (TER) develops in 4-5 h, presumably through exocytotic fusion that incorporates junctional components to the surface(More)
An epithelial cell line (MDCK) was used to prepare monolayers which, in vitro, develop properties of transporting epithelia. Monolayers were formed by plating cells at high densities (10(6) cells/cm2) on collagen-coated nylon cloth disks to saturate the area available for attachment, thus avoiding the need for cell division. An electrical resistance(More)
Synthesis and assembly of tight junctions are studied in monolayers of MDCK cells plated at a density sufficient for confluence, allowed to attach for 1 hr, and transferred to fresh media without cells containing or not Ca2+, 20 hr later, while monolayers with Ca2+ have fully developed junctions that confer an electrical resistance across of 346±51 Ω cm2,(More)
The making and sealing of a tight junction (TJ) requires cell-cell contacts and Ca2−, and can be gauged through the development of transepithelial electrical resistance (TER) and the accumulation of ZO-1 peptide at the cell borders. We observe that pertussis toxin increases TER, while AIF3 and carbamil choline (carbachol) inhibit it, and(More)
The experimental opening and resealing of occluding junctions in monolayers of cultured MDCK cells (epithelioid of renal origin) was explored by measuring changes in the electrical resistance across the monolayer and by freeze-fracture electron microscopy. As in natural epithelia, the function of occluding junctions as permeability barriers specifically(More)
We have previously shown that upon transferring confluent monolayers of Madin-Darby canine kidney (MDCK) cells from low- to normal-Ca2+ medium, cytosolic Ca2+ increases and tight junctions (TJs) assemble and seal, but the increase in cytosolic Ca2+ does not seem to be necessary for junction formation. In the present work we establish that these are in fact(More)
The aim of this paper is to obtain information on the number, nature and location of the barriers to Na movement across the frog skin, and on the size and location of the Na-pool that might be contained between these barriers. On the basis that Na penetrates passively across an outer barrier, and is actively extruded across an inner barrier which is(More)
The tight junction (TJ) is not randomly located on the cell membrane, but occupies a precise position at the outermost edge of the intercellular space and, therefore, is itself considered a polarized structure. This article reviews the most common experimental approaches for studying this relationship. We then discuss three main topics. (a) The mechanisms(More)