Feedbacks, Bifurcations, and Cell Fate Decision-Making in the p53 System
Fig 3
Scheme and the bifurcation diagrams for the apoptotic module.
(A) Scheme: pro-survival proteins are in blue boxes, pro-apoptotic proteins are in yellow boxes, other proteins or protein complexes are in gray boxes. The arrow notation is same as in Fig 1. (B) Saddle—node bifurcations line in the (p53KILLER, Aktp)-plane (2-D bifurcation diagram) separates the region of parameters for which apoptotic and survival states coexist from the region for which only the apoptotic state exists. (C) Bifurcation diagram for Casp vs. p53KILLER (bifurcation parameter) for Aktp; the saddle-node bifurcation point SN is (p53KILLER, Caspbif) ≅ (0.95×105, 1.5×103). (D) Bifurcation diagram for Casp vs. Aktp (bifurcation parameter) for p53KILLER ≅ 5×105; the saddle-node bifurcation point SN is (Aktp, Caspbif) ≅ (4.4×104, 1.5×103). The solid and dashed lines correspond respectively to the stable and unstable steady states. The number of eigenvalues with positive real parts is either one (1+) for the unstable steady state or zero (0+) for stable steady states. Notice the logarithmic scale on vertical axes in (C) and (D).