Abstract
DOI: 10.26650/electrica.2018.02664
From a system theory perspective, p53
network dynamics is interesting since it can exhibit three dynamical modes of
p53, namely low-level equilibrium, oscillation, and high-level equilibrium.
Each of these modes are associated with different cell fate outcomes: cell
survival, cell cycle arrest, and apoptosis. The literature reveals that a high
level (apoptosis) is seen only after ending the oscillation phase, so called
two-phase dynamics, which provides the decision of apoptosis depending on the
oscillation duration. This paper proposes that a negative feedback can keep
time by counting the pulses of oscillation to take the decision of apoptosis or
cell survival. P53DINP1, which is the mediator of this feedback, is added as a
variable to a 2-D oscillator model of the p53 network. The resulting canonical
3-D model successfully replicates the two-phase dynamics. That is, it possesses
temporary oscillatory behavior, in which first oscillations (first phase) and
then high level state (second phase) are observed. By introducing a new
variable to the core oscillator in the p53 network, this study demonstrates
that p53 network can be considered a modular structure, which consists of an
oscillator and other variables that control this oscillator to contribute to
cell fate determination.