Computational Model Explains High Activity and Rapid Cycling of Rho GTPases within Protein Complexes
Figure 5
Simulation of the Yeast cdc42p Cycling In Vitro
(A) Kinetics of GDP dissociation from [3H]GDP-bound cdc42p after mixing with GTP. Comparison of the model simulations and experimental results [59] is shown as groups a and b for the reactions with and without GEF cdc24p, respectively. Concentrations of cdc42p, cdc24p, and GTP were 90 μM, 28 μM, and 100μM.
(B) Simulation of GAP-stimulated GTP hydrolysis by cdc42p. Experimental data are for the yeast GAP Bem3 [60]. GTP hydrolysis was essayed by measuring phosphate (Pi) release over 5 min. Initial concentration of [γ-32P]GTP-bound cdc42p was 0.1 μM. Simulation results are shown by solid lines.