Figure 4.

Model predictions of 1A perturbation and effect of the disruptor peptide. (A) Simulations of MST2 activation in response to increasing Ras-GTP under high and down-regulated RASSF1A expression. (B) Illustration of the biphasic property of MST2 activation dependence on RASS1F level. (C–F) Simulations of various model species in response to increasing level of the MST2-Raf-1 binding disruptor peptide. Parameter values for the kinetic rates of binding between the peptide and inactive MST2 are k_f = 0.1 nM⁻¹s_­⁻¹, k_r = 0.001 s_­⁻¹, k_act = 0.02 nM⁻¹ using the same published model in.²⁴ The other parameter values are given in Table M3 of ref.²⁴ (G) HeLa cells were incubated with increasing concentrations (0–10 μM) of stearylated scrambled (Stear-scrambled) or MST2 (Stear-MST2) disruptor peptides for 1 hour. Raf-1 and Mst2 immunoprecipitates and 10 μg of cellular extracts were analyzed by Western blotting using the indicated antibodies. (H and K) Blots were quantitated by laser densitometry and analyzed using the Image J software.