We have observed the presence of membrane junctions formed between the plasma membrane and cortical endoplasmic reticulum of mature, unactivated eggs of xenopus laevis. The parallel, paired membranes of the junction are separated by a 10-mn gap within which electron-dense material is present. This material occurs in patches with an average center-to-center distance of approximately 30 nm. These...

The distribution of intercellular junctions, other than synapses and their precursors, has been described in the developing spinal cord of Xenopus laevis between the neurula and free swimming tadpole stages. At the neurocoel, ventricular cells are joined in the apical contact zone by a sequence of junctions which usually has one or more intermediate junctions but also includes close appositions...

Cell-cell junctions are essential for epithelial and endothelial tissue formation and communication between neighboring cells. We report here that migfilin, a recently identified component of cell-extracellular matrix adhesions, is recruited to cell-cell junctions in response to cadherin-mediated cell-cell adhesions. Migfilin is detected at cell-cell junctions in both epithelial and endothelial...

The bioluminescent scales of the polynoid worm Acholoe are covered by a dorsal and ventral monolayer of epithelium. The luminous activity is intracellular and arises from the ventral epithelial cells, which are modified as photocytes. Photogenic and non-photogenic epithelial cells have been examined with regard to intercellular junctions and electrophysiological properties. Desmosomes, septate ...

The transmembrane connexin proteins of gap junctions link extracellularly to form channels for cell-to-cell exchange of ions and small molecules. Two primary hypotheses of gap junction coupling in the CNS are the following: (1) generalized coupling occurs between neurons and glia, with some connexins expressed in both neurons and glia, and (2) intercellular junctional coupling is restricted to ...

The assembly of gap junctions was investigated in mammalian cells expressing connexin (Cx) 26, 32 and 43 fused to green, yellow or cyan fluorescent proteins (GFP, YFP, CFP). Targeting of Cx32-CFP and 43-GFP to gap junctions and gap junctional communication was inhibited in cells treated with Brefeldin A, a drug that disassembles the Golgi. However gap junctions constructed of Cx26-GFP were only...

Electron tunneling experiments involving Hg-Hg junctions incorporating two alkanethiolate monolayers are described. Formation of a symmetric junction (Hg-SCn-CnS-Hg) is accomplished by bringing in contact two small (3 × 10-3 cm2) mercury drop electrodes in a 5-20% (v/v) hexadecane solution of an alkanethiol. Formation of asymmetric junctions (Hg-SCn-CmS-Hg) and junctions containing n-alkane-3th...

The ultrastructure of myometrial tissues from nonpregnant, pregnant and postpartum sheep was quantitatively examined for the presence of gap junctions between smooth musde cells. Serum concentrations of estrone, estradiol and progesterone were determined in some of the sheep prior to and at the time of sacrifice. Gap junctions were not present in any tissue from nonpregnant animals or in tissue...

The development of cell-cell junctions was a fundamental step in metazoan evolution, and human health depends on the formation and function of cell junctions. Although it has long been known that actin and conventional myosin have important roles in cell junctions, research has begun to reveal the specific functions of the different forms of conventional myosin. Exciting new data also reveals t...

Endothelial cells (ECs) form a monolayer that serves as a barrier between the blood and the underlying tissue. ECs tightly regulate their cell-cell junctions, controlling the passage of soluble materials and immune cells across the monolayer barrier. We studied the role of N-WASP, a key regulator of Arp2/3 complex and actin assembly, in EC monolayers. We report that N-WASP regulates endothelial...