Meeting Abstract

47.3  Sunday, Jan. 5 10:45  Evolution of the Cadherin-Catenin Adhesion Complex: Insights from the Starlet Sea Anemone, Nematostella vectensis CLARKE, DN*; MILLER, PW; LOWE, CJ; NELSON, WJ; Stanford University clarken@stanford.edu

A simple epithelium is a sheet of cells that separates the inside of an organism from the surrounding environment, and is thought to be the first organized multicellular tissue to occur in animal evolution. Epithelial cells adhere to each other via specialized cell-cell adhesion proteins. The Cadherin-Catenin Adhesion Complex (CCC), consisting of classical cadherin, β-catenin, and α-catenin, has been shown to be necessary for the initial formation of epithelial cell junctions in bilaterian model systems, and plays a critical structural role by linking the plasma membrane to the internal actin cytoskeleton. As the emergence of the core components of the CCC corresponds with the origin of animals, the adhesive function of the complex may have been coincident with animal multicellularity, or it may have been a later refinement of the Bilateria, but as the basic functions of the constituents of the CCC remain untested outside of bilaterians, this hypothesis remains untested. Furthermore, recent findings indicate that despite a high level of sequence conservation in the CCC across the Metazoa, the functional properties of its constituent proteins are quite variable between bilaterian taxa. We currently lack the functional and molecular descriptions of CCC components from a basally branching metazoan to determine conservation and variability in CCC function. We therefore examined CCC protein interactions and sub-cellular localization in the anthozoan cnidarian, Nematostella vectensis. Our results, based on in-vitro protein biochemistry and immunofluorescence using affinity-purified, cross-reactive antibodies, show that the basic functional interactions and localization to cell contacts of the Cadherin-Catenin Complex are conserved outside of the Bilateria.