The small GTP-binding protein, Rab 17 is implicated in the regulation of endocytosis and/or transcytosis in epithelial cells once these cells become polarized.
To elucidate the precise functional role of rab 17 protein, we would like to examine whether an overexpression of wild type Rab 17 or dominant interfering mutants affects transcellular transport in cultured polarized epithelial cells. For that, we would like to subclone the cDNA of Rab 17 and Rab 17 mutants
defective in GTP-binding, under the control of the MX promoter, an IFNy inductive promoter, and to transfect MDCK cells with these constructs. Then, we will measure the rate of the HRP fluid phase. Moreover, we would like to identify specific proteins interacting with Rab 17 in the aim to define its functional mechanism. We will use both a genetic approach by the double hybrid system in yeast and a biochemical approach to identify factors that regulate the GTP/GDP cycle of Rab 17 and specific effectors.