In contrast to epithelial cells, cardiomyocytes are connected by complex hybrid-type adhering junctions, termed composite junctions (areae compositae). Composite junctions are found to be composed of typical desmosomal as well as adherens junction proteins. Therefore, in adult mammalian cardiomyocytes desmosomal proteins are not restricted to the relatively small desmosomes but are indirectly i...

The fine structure and distribution of tight (zonula occludens) and gap junctions in epithelia of the rat pancreas, liver, adrenal cortex, epididymis, and duodenum, and in smooth muscle were examined in paraformaldehyde-glutaraldehyde-fixed, tracer-permeated (K-pyroantimonate and lanthanum), and freeze-fractured tissue preparations. While many pentalaminar and septilaminar foci seen in thin-sec...

A systematic survey of endothelial junctions in elastic (aorta) and muscular (mesenteric) arteries and in medium (renal and mesenteric) and large (cava inferior) size veins has been carried out in the rat using freeze-cleaved preparations. The arterial endothelium is provided with a complex of occluding and communicating junctions (gap junctions) comparable to, though less elaborate than, that ...

The endoplasmic reticulum (ER) consists of a polygonal network of sheets and tubules interconnected by three-way junctions. This network undergoes continual remodeling through competing processes: the branching and fusion of tubules forms new three-way junctions and new polygons, and junction sliding and ring closure leads to polygon loss. However, little is known about the machinery required t...

Cultured cells from either chicken lens or liver plated on solid substrates form flat epithelial sheets with adherens-type junctions between them. In lens cells these junctions contain A-CAM, while the same type of intercellular junctions in liver cells contain another cell adhesion molecule, L-CAM. Coculturing of lens and liver cells in the same dish resulted in the formation of mixed (heterot...

Tight junctions are crucial for maintaining the polarity and vectorial transport functions of epithelial cells. We and others have shown that Na-K-ATPase plays a key role in the organization and permeability of tight junctions in mammalian cells and analogous septate junctions in Drosophila. However, the mechanism by which Na-K-ATPase modulates tight junctions is not known. In this study, using...

This paper describes a new method for validating and classifying 3D junctions by combining detected intensity-based junctions and contour-based junctions. The resulting algorithm is divided in four steps: (i) the pairing of junctions according to proximity criteria, (ii) the matching of brancheslsegments of paired junctions, (iii) the validation of isolated junctions according to paired junctio...

In the normal heart, the atrio-ventricular node (AVN) is responsible for the appropriate atrio-ventricular delay. Most of the slow conduction in AVN is probably caused by the small number of gap junctions connecting the myocytes [1]. Experimental and theoretical studies show that although conduction velocity decreases by reducing gap junctions, in such conditions safety factor increases [2]. Di...