Consistent with these findings, LI-cadherin was not resistant to detergent extraction and did not induce a reorganization of the actin cytoskeleton

Consistent with these findings, LI-cadherin was not resistant to detergent extraction and did not induce a reorganization of the actin cytoskeleton. LI-cadherin is definitely self-employed of any connection with cytoplasmic parts, and consequently should Gja5 not be sensitive to regulatory mechanisms influencing the binding of classical cadherins to catenins and to the cytoskeleton. Therefore, we postulate the adhesive function of LI-cadherin is definitely complementary to that of coexpressed classical cadherins ensuring cellCcell contacts actually under conditions that downregulate the function of classical cadherins. Cadherins ITI214 are a multifunctional family of transmembrane glycoproteins mediating Ca2+-dependent adhesion of adjacent cells inside a homophilic manner (Takeichi, 1988, 1991; Geiger and Ayalon, 1992; Kemler, 1993). Users of this family have been reported to be involved in morphogenesis (Takeichi, 1995), the development of junctional complexes and cell polarity (Nelson, 1992), invasiveness and metastasis (Birchmeier and Behrens, 1994), and most recently, transmembrane transport (Dantzig et al., 1994; Thomson et al., 1995). Classical cadherins are composed of a highly conserved cytoplasmic website of 160 amino acids, a single transmembrane website, and a large extracellular portion that is organized in a series of five structurally related tandem repeats (Ranscht, 1994). The conserved intracellular website of classical cadherins is known to associate with a group of cytoplasmic proteins, termed catenins (Ozawa et al., 1989), which serve mainly because a link between cadherins and the cortical cytoskeleton (Hirano et al., 1987). As shown by several experiments, the formation of complexes with catenins is essential for cadherins to function as adhesion molecules. First evidence for the crucial role of this association came from studies, in which cadherins were rendered nonfunctional by COOH-terminal truncations influencing the catenin-binding site (Nagafuchi and Takeichi, 1988, 1989; Ozawa et al., 1989, 1990). Furthermore, in nonadhesive Personal computer9 cells ITI214 lacking -catenin, strong cellCcell adhesion could be restored by transfection with -catenin cDNA indicating that the manifestation of -catenin is required for the adhesive function of cadherins (Hirano et al., 1992). -Catenin is definitely homologous to vinculin (Herrenknecht et al., 1991; Nagafuchi et al., 1991) and is a candidate for linking the cadherin /catenin complex to the actin-based cytoskeleton (Ozawa et al., 1990; Nagafuchi et al., 1994). -Catenin exhibits homology to plakoglobin, a component of desmosomal plaques and adherens junctions (Cowin et al., 1986), and to the product of the section polarity gene (McCrea et al., 1991; Butz et al., 1992; Peifer et al., 1992). The primary structure of -catenin has not yet been founded, but there is growing evidence that it might be identical to plakoglobin (Knudsen and Wheelock, 1992; Peifer et al., 1992; Piepenhagen and Nelson, 1993). Like the armadillo protein, -catenin is definitely thought to be involved in transmission transduction and developmental patterning (examined by Gumbiner, 1995; Khl and Wedlich, 1996). Recent studies suggested that -catenin might be a target molecule for the rules of cadherin function, since epithelial cells transformed with the v-Src tyrosine kinase acquired a more mesenchymal morphology, ITI214 that was correlated with a strong phosphorylation of -catenin and the perturbation of cadherin activity (Matsuyoshi et al., 1992; Behrens et al., 1993; Hamaguchi et al., 1993). A similar switch in morphology could be induced by treatment with EGF or hepatocyte growth element/scatter element, which caused tyrosine phosphorylation of -catenin as well as of plakoglobin (Weidner et al., 1990; Shibamoto et al., 1994). These observations suggest that tyrosine phosphorylation of catenins affects cadherin- mediated cellCcell adhesion. Recently, LI-cadherin was characterized like a novel member of the cadherin family specifically indicated in polarized epithelia of liver and intestine (Berndorff et al., 1994). In intestinal epithelial cells, LI-cadherin is definitely evenly distributed on the lateral contact zones but is definitely excluded from adherens junctions, whereas coexpressed E-cadherin is concentrated in this specialized membrane region. LIcadherin exhibits an unusual structure, since its extracellular website is composed of seven cadherin-type repeats instead of five standard for classical cadherins. In addition, its short cytoplasmic domain consists of only 20 amino acids exhibiting no homology to this highly conserved region of classical cadherins. However, LI-cadherin was shown to act as a functional.

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