Tight junctions and the experimental modifications of lipid content

Tight junctions (TJs) are cell-to-cell contacts made of strands, which appear as ridges on P faces and complementary furrows on E faces on freeze fracture replicas. Evidences and opinions on whether these strands are composed of either membrane-bound proteins or lipid micelles are somewhat varied. I...

Full description

Saved in:
Bibliographic Details
Published in:The Journal of membrane biology 1998-07, Vol.164 (1), p.59-69
Main Authors: Calderón, V, Lázaro, A, Contreras, R G, Shoshani, L, Flores-Maldonado, C, González-Mariscal, L, Zampighi, G, Cereijido, M
Format: Article
Language:English
Subjects:
Animals
Boron Compounds - metabolism
Cell Line
Chickens
Cholesterol - metabolism
Dogs
Electric Impedance
Fatty Acids - metabolism
Fluorescent Dyes - metabolism
Kidney - cytology
Membrane Proteins - genetics
Membrane Proteins - metabolism
Occludin
Phospholipids - metabolism
Sphingomyelins - metabolism
Tight Junctions - metabolism
Tight Junctions - physiology
Transfection
Citations: Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Tight junctions (TJs) are cell-to-cell contacts made of strands, which appear as ridges on P faces and complementary furrows on E faces on freeze fracture replicas. Evidences and opinions on whether these strands are composed of either membrane-bound proteins or lipid micelles are somewhat varied. In the present work we alter the lipid composition of Madin-Darby canine kidney monolayers using a novel approach, while studying (i) their transepithelial electrical resistance, a parameter that depends on the degree of sealing of the TJs; (ii) the apical-to-basolateral flux of 4 kD fluorescent dextran (JDEX), that reflects the permeability of the intercellular spaces; (iii) the ability of TJs to restrict apical-to-basolateral diffusion of membrane lipids; and (iv) the pattern of distribution of endogenous and transfected occludin, the sole membrane protein presently known to form part of the TJs. We show that changing the total composition of phospholipids, sphingolipids, cholesterol and the content of fatty acids, does not alter TER nor the structure of the strands. Interestingly, enrichment with linoleic acid increases the JDEX by 631%. The fact that this increase is not reflected in a decrease of TER, suggests that junctional strands do not act as simple resistive elements but may contain mobile translocating mechanisms.
ISSN:0022-2631
1432-1424
DOI:10.1007/s002329900393