Junction structure

When cells lie adjacent to each other in animal tissues, they are often connected by gap junction structures, which permit the passive flow of small molecules from one cell to the other. Such junctions essentially connect the cells metabolically, providing a means of chemical transfer and communication. In certain tissues, such as heart muscle that is not innervated, gap junctions permit very large numbers of cells to act synchronously. Gap junctions also provide a means for transport of nutrients to cells disconnected from the circulatory system, such as the lens cells of the eye. 

Hirsch M, W Noske. (1993). The tight junction Structure and function. Micron 24 325-352. 

Madara JL. (1983). Increases in guinea pig small intestinal transepithelial resistance induced by osomotic loads are accompanied by rapid alterations in absorptive-cell tight-junction structure. J Cell Biol 97 125-136. 

Cavanaugh KJ Jr, Oswari J, Margulies SS (2001) Role of stretch on tight junction structure in alveolar epithelial cells. Am J Respir Cell Mol Biol 25(5) 584—591... 

Madara JL and Dharmsathaphorn K [1985] Occluding junction structure function relationships in a cultured epithelial monolayer. J Cell Biol 101 2124-2133... 

Martial MA, Carlson SL, and Madara JL [1987] Partitioning of paracellular conductance along the ileal crypt-villus axis a hypothesis based on structural analysis with detailed consideration of tight junction-structure function relationships. J Membr Biol 80 59-70... 

Williams H, Neuhaus J, Kniesel U, KrauB B, Schmid E-M, Ocalan M, Farell C, Risau W (1980) Modulation of tight junction structure in blood-brain barrier endothelial cells. J Cell Sci 107 1347-1357... 

Table 11.11. Principal standard tableaux Junction structures for C2 at the energy minimum bond distance.

Table 11.21. Principal standard tableaux and HLSP Junction structures for F2 at an asymptotic bond distance.

Larsen WJ Biological implications of gap junction structure, distribution and composition A review. Tissue Cell 1983 15 645-671. 

Makowsky L X-ray diffraction studies of gap junction structure. Adv Cell Biol 1988 2 119-158. 

Makowsky L, Caspar DLD, Phillips WC, Goodenough DA Gap junction structures. II. Analysis of the X-ray diffraction data. J Cell Biol 1977 74 629-645. 

Sosinsky GE, Jesior JC, Caspar DLD, Goodenough DA Gap junction structures. VIII. Membrane cross-sections. Biophys J 1988 53 709-722. 

Zampighi G Gap junction structure in DeMello WC (ed) Cell-to-Cell Communication. New York, Plenum Press, 1987, pp 1-28. 

Special structural features may be found at junctions between different types of DNA, e.g., between A-DNA and B-DNA.284-286 However, the most interesting junctions are branched.287 29° For example, Fig. 5-28 shows a four-way junction in which all of the bases form Watson-Crick pairs. This junction is better known as a Holliday junction because it was proposed by Holliday in 1964 as an intermediate in genetic recombination.291 As shown at the top of Fig. 5-28A the junction is formed from two homologous DNA duplexes. These are identical except for the boxed and shaded base pairs. The ends of the first duplex are marked I and II and those of the second III and IV. The Holliday junction appears to arise by cleavage of one strand of each duplex with rejoining of the strands as indicated by the green arrows. Rotation gives the untwisted Holliday junction structure... 

Gap junctions are formed from hexagonal arrays of a rod-shaped protein. Arrays in the membranes of adjacent cells line up to form intercellular channels that can transmit small molecules from cell to cell in some tissues. (Source Adapted from L. Makowski, D. L. D. Caspar, W. C. Phillips, and D. A. Goodenough, Gap junction structures. II. Analysis of the x-ray diffraction data,./. Cell Biol. 74 629, 1977.)... 

In the case of ring-fused systems the cis/trans notation is used to designate the geometric nature of the ring junction. Structures (25) and (26) represent partial structures of the ring-fused compounds (13) and (14) respectively, which emphasise that the ring junctions utilise cis- or frans-orientated bonds. 

Mitic, L.L., C.M. van Itallie, and J.M. Anderson. 2000. Molecular physiology and pathophysiology of tight junctions. I. Tight junction structure and function Lessons from mutant animals and proteins. Am J Physiol 297 G250. 

FIGURE 7.27 Micromachined ISE chip, (a) Schematic drawing of a sensor chip design with channels and reservoirs point A, inlet for U-channel point B, outlet for U-channel point C, inlet for sample channel point D, junction structure, where membrane contacts sample solution and point E, outlet for sample channel. The diagram illustrates the complete filling of the silanized U-channel with an organic membrane cocktail, (b) Scaled diagram of the 12- x 6-mm chip [766]. Reprinted with permission from the American Chemical Society. 

In 1981 an efficiency of 7.5% was obtained for a p-i-n structure (3.3 mm2) in which the p layer was a boron-doped silicon-carbon-hydrogen alloy (a-Si C H) (Tawada et al., 1981). A further improvement in conversion efficiency to 8.5% was obtained in 1982 with a stacked junction structure (9 mm2) that utilized an amorphous silicon-germanium-hydrogen alloy (a-Si Ge H) in the back junction of three stacked p-i-n junctions (Nakamura et al., 1982). More recently, an efficiency of 10.1% has been achieved in a p-i-n structure (1.2 cm2) utilizing p-type a-Si C H as a window layer (Catalano et al., 1982). 

One more interesting structure, also representing an unusual metal-binding center, is the DNA cruciform (or four-way junction) structure. This type of structure results from rearrangement of palindromes (inverted repeat sequences) and may be formed reversibly under certain conditions (e.g. to relax strain in supercoiled DNA). The relative efficiency of different divalent metal ions in promoting the formation of DNA cruciform structures is Mg + > Mn + > Co + >... 

Miller, T. M. and Goodenough, D. A. (1985). Gap junction structures after experimental alteration of junctional channel conductance. J. Cell Biol. 101, 1741-1748. 

Stevenson BR et al (1988) Tight junction structure and ZO-1 content are identical in two strains of Madin-Darby canine kidney cells which differ in transepithelial resistance. J Cell Biol 107(6 Pt l) 2401-2408... 

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