Structural & functional studies of DOCK-family guanine nucleotide exchange factors. (360G-Wellcome-090173_Z_09_Z)

The aims of this PhD project are: (i) to provide a molecular understanding of the mechanism of GTPase guanine nucleotide exchange by the DHR2 domain of DOCK3 and DOCK180, (ii) to define the molecular basis for their specificity for Rae members of the Rho-family of GTPases, (iii) to investigate the possibility of developing small molecules that inhibit the GEF activity of DOCK180/3 and (iv) to apply information obtained from the X-ray structure of DOCK180/3-Rac complexes to generate mutations that affect GEF activity to delineate functions of DOCK180/3 in cell-based experiments. The structure of the DHR2 domains of DOCK180 and DOCK3 will be determined by X-ray protein crystallography in isolation and in complex with Rae. A high throughput structure-based screen (Jhoti et al., 2007) will be developed to identify agonists and antagonists of the DHR2 domain-Rae interaction. Finally the cellular consequences of disrupting the GEF activity of DOCK180/3 will be analysed by monitoring the consequences of Rae activation in vivo.