In silico screening of Rac1 ligand specificity.

Microtubule (MT) destabilization promotes the formation of actin stress fibers and enhances the contractility of cells. The actin cytoskeleton is bound to each junction and controls the integrity of each through actin remodeling and these junctions can be disassembled or assembled to either increase or decrease cellular permeability. Mediators, such as thrombin, stimulate their respective receptor on endothelial cells to initiate signaling that increases cytosolic Ca2+ and activates myosin light chain kinase (MLCK), as well as monomeric GTPases RhoA, Rac1, and Cdc42. Ca2+ activation of MLCK and RhoA disrupts junctions, whereas Rac1 and Cdc42 promote junctional assembly. In order to develop formal systems biology model of actin remodelling it is necessary to investigate the reciprocal interactions between Rac1 and Cdc42 by using experimental selective inhibition. We have screened, by docking analysis, a new class of compounds for Rac1 and/or Cdc42 inhibition, the Morpholinos, that could be used as alternative tool to switch off a gene.