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A model for a bistable biochemical trigger of mitosis
1Department of Pharmacology and Toxicology, Dartmouth Medical School, Hanover, NH 03755-3835, USA.
Biophysical Chemistry
|January 1, 1996
Summary
Maturation promoting factor (MPF) activation initiates mitosis via a bistable switch. This biochemical trigger exhibits hysteresis, ensuring robust cell cycle progression through a saddle-node bifurcation.
Area of Science:
- Biochemistry
- Cell Biology
- Systems Biology
Background:
- Mitosis initiation is regulated by the activation of maturation promoting factor (MPF).
- Understanding the precise molecular mechanisms controlling MPF activation is crucial for cell cycle control.
Purpose of the Study:
- To model the activation of MPF as a bistable biochemical switch.
- To identify the key kinetic features enabling MPF bistable triggering and hysteresis.
Main Methods:
- Biochemical modeling of MPF activation dynamics.
- Analysis of saddle-node bifurcation for abrupt transitions.
- Investigation of mutual activation and inhibitory binding mechanisms.
Main Results:
- MPF activation functions as a bistable switch, transitioning abruptly from low to high activity via a saddle-node bifurcation.
- The switch exhibits hysteresis, meaning it does not reverse upon parameter change.
- Mutual activation between MPF and Cdc25 creates autocatalysis, while Suc1 binding stabilizes the low-activity state.
Conclusions:
- Bistable triggering, characterized by two stable states and hysteresis, is a key feature of MPF activation for robust mitosis initiation.
- The interplay between autocatalysis and inhibitory binding (Suc1) generates the necessary dynamics for this switch.
- This model provides insights into general biochemical mechanisms capable of producing bistable switches.