Some of these GTPases, particularly the Rac1 homologous protein Rac2 that is expressed in haematopoietic cells, control processes such as phagocytosis and the production of reactive oxygen species involved in micro-organism destruction (Diebold and Bokoch, 2005).Regulation of Rho GTPasesSignals that emanate from cell-surface receptors are relayed to Rho GTPases by GEFs (guanine-nucleotide-exchange