Cadherins are a multigene family of proteins which mediate homophilic calcium-dependent cell adhesion and are thought to play an important role in morphogenesis by mediating specific intercellular adhesion. Different lines of experimental evidence have recently indicated that the site responsible for mediating adhesive interactions is localized to the first extracellular domain of cadherin. Based upon an analysis of the sequence of this domain, I show that cadherins can be classified into three groups with distinct structural features. Furthermore, using this sequence information a phylogenetic tree relating the known cadherins was assembled. This is the first such tree to be published for the cadherins. One cadherin subtype, neural cadherin (N-cadherin), shows very little sequence divergence between species, whereas all other cadherin subtypes show more substantial divergence, suggesting that selective pressure upon this domain may be greater for N-cadherin than for other cadherins. Phylogenetic analysis also suggests that the gene duplications which established the main branches leading to the different cadherin subtypes occurred very early in their history. These duplications set the stage for the diversified superfamily we now observe.
"Cell adhesion molecules act as signal transducers from the extracellular environment to the cytoskeleton and the nucleus and consequently induce changes in the localization pattern of structural proteins (George and Dwivedi 2004; Izaguirre et al. 2008). The main cell adhesion molecules involved in vertebrate morphogenesis are the cadherins (Takeichi 1988), that belong to a superfamily of calcium-dependent cell adhesion molecules (Takeichi 1988, 1991; Pouliot 1992). Members of the cadherin superfamily are expressed according to well-defined patterns associated with different temporal phases of "
[Show abstract][Hide abstract] ABSTRACT: During amphibian metamorphosis, modifications of several important body systems take place involving different molecular mechanisms driving, among other, cell differentiation, cell-cell adhesion, and extracellular matrix turnover. Amphibians have been used as a classic model to investigate organs remodelling, including the skin; however, previous studies on metamorphosis have examined, for the most part, anurans, whereas only a few reports have considered urodeles. The main goal of this study was to evaluate the presence of keratins in the epidermis of the Italian newt (Lissotriton italicus). In order to assess the putative differential expression of keratins, we immunodetected cytokeratin type I, type II, and high molecular weight (HMW) during the larval, pre-metamorphic, and adult phase. Our results clearly indicated that keratins expression changes as the epidermis modifies during the functional maturation; interestingly, HMW keratins showed a strong immunopositivity in adult, thus suggesting that, in urodeles, these keratins become expressed in adult epidermis. Moreover, by using a monoclonal antibody against pan-cadherin, we demonstrated that in L. italicus epidermis during pre-metamorphic stages, the conversion from larval to adult type is not completed in whole epidermis; we also showed the strong spatiotemporal correlation of stromelysin-3 expression with tissue remodelling in L. italicus skin. Considering that skin remodelling in urodeles is a topic relatively neglected, our findings will contribute to fill a gap in the existing research literature; moreover, these data emphasize that unexpected results could be obtained when different model systems were used.
"The comparison revealed that the putative protein is a novel member of the cadherin superfamily. The BS-cadherin bears a similarity to classical cadherins in its basic structure throughout its entire length (Fig. 3), including a signal peptide (aa 1–26), a putative precursor peptide (aa 26–172), a large extracellular domain (aa 172–724), a 30-aa-long transmembrane domain and a cytoplasmic tail ( Takeichi, 1991; Geiger and Ayalon, 1992; Pouliot, 1992; Grunwald, 1993). Fig. 4A shows the alignment of the deduced amino acid sequence of BS-cadherin with human N-, E-and P-cadherins that represent classical type I cadherins and with human cadherin-6, human cadherin-8 and human OB-cadherin that represent classical cadherins type II. "
[Show abstract][Hide abstract] ABSTRACT: The genomic DNA for a novel member of the cadherin family (BS-cadherin) was cloned and characterized from the colonial marine invertebrate, Botryllus schlosseri. Using a differential display of mRNA by means of PCR, a small cDNA fragment of 380 nucleotides was found to be specifically expressed in a colony undergoing allogeneic rejection processes, as compared with naive parts of the same genotype. This cDNA fragment was used as a probe to screen a genomic library of Botryllus schlosseri. A genomic fragment containing an ORF of 2718 nucleotides, with no introns, was isolated. The encoded protein exhibits a typical structure of cadherins; an extracellular domain with conserved repeated sequences (cadherin signatures), a single transmembrane domain and a conserved cytoplasmic tail region. The BS-cadherin amino-acid sequence shows 32-35% identity to mature classical cadherins type I, e.g., N-, P- and E-cadherin as well as mature classical cadherins type II, e.g., human cadherin-6, -8 and OB-cadherin. This cadherin represents a new cadherin gene family, evolutionarily distant to all other known classical cadherins.
"Initially identified in vertebrates, cadherins have recently also been observed in invertebrates , e.g., Drosophila and Caenorhabditis elegans (Sano et al., 1993; Oda et al., 1994). This supports the idea of cadherins as an evolutionarily conserved adhesion principle (Pouliot, 1992; Grunwald, 1993). Depending on the conserved sequence motifs, the following subfamilies can be distinguished: classical (also known as type I) cadherins, type I1 cadherins, protocadherins , and desmosomal cadherins. "
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