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Multiple domains of occludin are involved in the regulation of paracellular permeability
Author(s) -
Balda Maria S.,
FloresMaldonado Catalina,
Cereijido Marcelino,
Matter Karl
Publication year - 2000
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/(sici)1097-4644(20000701)78:1<85::aid-jcb8>3.0.co;2-f
Subject(s) - paracellular transport , occludin , tight junction , microbiology and biotechnology , claudin , transmembrane protein , cell junction , biology , transport protein , transmembrane domain , intracellular , transcellular , chemistry , biophysics , permeability (electromagnetism) , biochemistry , membrane , cell , receptor
Tight junctions form selective paracellular diffusion barriers that regulate the diffusion of solutes across epithelia and constitute intramembrane diffusion barriers that prevent the intermixing of apical and basolateral lipids in the extracytoplasmic leaflet of the plasma membrane. In MDCK cells, previous expression experiments demonstrated that occludin, a tight junction protein with four transmembrane domains, is critically involved in both of these tight junction functions and that its COOH‐terminal cytoplasmic domain is of functional importance. By expressing mutant and chimeric occludin that exert a dominant negative effect on selective paracellular diffusion, we now demonstrate that the extracytoplasmic domains and at least one of the transmembrane domains are also critically involved in selective paracellular permeability. Multiple domains of occludin are thus important for the regulation of paracellular permeability. Expression of chimeras containing at least one transmembrane domain of occludin also resulted in an enhanced intracellular accumulation of claudin‐4, another transmembrane protein of tight junctions, suggesting that the two proteins may cooperate in the regulation of paracellular permeability. J. Cell. Biochem. 78:85–96, 2000. © 2000 Wiley‐Liss, Inc.