A model for Rac activation through the phosphorylation of rhoGDI by Pak
Cell stimulation activates Pak leading to the phosphorylation of inactive rhoGDI-Rac complexes in the cytosol. Phosphorylated GDI dissociates from Rac, allowing Rac to become activated by binding GTP. Active Rac then exerts its biological effects, including activation of Pak itself. This results in a positive feedback loop to promote Rac activity. This may be important for processes like continuous cell motility.