UBC Theses and Dissertations
The intracellular binding partners of Gliotactin MacKinnon, Christina Marie
Septate Junctions consist of a complex of proteins that establishes and maintains a functional permeability barrier. Gliotactin, a protein required for proper establishment and function of septate junctions, is hypothesized to complex with other septate junction proteins through interactions with its intracellular domain. Two biochemical methods were employed to identify and verify Gliotactin binding partners; a Yeast Two Hybrid Screen and Gliitatione-S-Transferase (GST) Pulldowns. Previous research indicated that Gliotactin interacts genetically with Discs large and can be isolated in a complex with Discs large in co-immunoprecipitation studies. However, GST Pulldown assays showed the two proteins do not directly bind. GST Pulldowns did show that Gliotactin binds with Magi, another PDZ domain containing protein. A Yeast Two Hybrid screen identified a potentially novel interaction with dAif6. dAif6 is found ubiquitously in Drosophila and localizes just below the taenidial folds late in tracheal development. GST Pulldown assays were inconclusive as to whether or not Gliotactin and dAif6 bind directly. However, given that Gliotactin, an essential member of septate junctions, complexes with other members, suggests that Discs large and dArf6 may also be a part of a larger complex of proteins. Further biochemical studies are required to further identify novel members of the complex and Gliotactin binding partners.
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