Further observations on the fine structure of freeze-cleaved tight junctions

作者：L. Andrew Staehelin · 发表于：Journal of Cell Science · 年份：1973 · DOI：10.1242/jcs.13.3.763 · 被引用次数：516 · 研究领域：Barrier Structure and Function Studies、Connexins and lens biology、Gut microbiota and health

ABSTRACT The fine structure of freeze-cleaved tight junctions has been examined in high-resolution replicas of rat small intestine. By carefully comparing the changes in the surface topography of the cleavage faces of specimens, which, before freezing, were either prefixed with glutaraldehyde and then infiltrated with glycerol, infiltrated with glycerol alone, or infiltrated with glycerol and then fixed with glutaraldehyde, a more precise definition of the tight-junction architecture at the supramolecular level has become possible. The results of this analysis suggest that the bilayer membranes contributing to a tight junction are held together along interconnected fines of attachment that are arranged in the form of a continuous band-like meshwork. Each line consists of 2 parallel rows, one in each membrane, of closely spaced adhesion particles. The sensitivity of these particles to glutaraldehyde and their cleaving behaviour under different experimental conditions indicate that they represent globular proteins which bridge the width of the adjoining membranes and are linked together in the plane of the intercellular space. Thus, the morphology of a tight-junction seal resembles a modified zipper with the locking units making head to head contact. Similarly, the presence of many open-ended sealing elements between crypt cells has been interpreted as suggesting that the formation of tight-junction seals could resemble a ‘zippering-up’ process. At the juncture of 3 cells the t...