A Protein Turnover Signaling Motif Controls the Stimulus-Sensitivity of Stress Response Pathways

Figure 3

A model of p53 oscillations in response to ionizing radiation.

(A) The model shown here is structurally identical to [17], but parameter values have been scaled to match published rates of synthesis and degradation for p53 and Mdm2 as well as their steady-state abundances (see Methods). (B) Ionizing radiation is modeled as an increase in synthesis of the Signal molecule (left; model parameter ) [17]. In response to a step increase in Signal production, phosphorylated p53 is observed to oscillate. We define to be the amplitude of the stable oscillations. In response to a 2-hour pulse in Signal production (right), p53 exhibits a transient peak in phosphorylation, as does Mdm2. We define to be the amplitude of phosphorylated p53, and to be its amplitude in response to a second, identical pulse, 22 hours after the first pulse.

doi: https://doi.org/10.1371/journal.pcbi.1002932.g003