Compact modeling of allosteric multisite proteins: application to a cell size checkpoint

Area of Science:

• Biochemistry
• Systems Biology
• Cell Signaling

Background:

• Allosteric multisite phosphorylation proteins are crucial in cellular regulation.
• Modeling their complex dose-response behaviors is challenging.
• Existing models like Monod-Wyman-Changeux or rule-based models can be computationally intensive.

Purpose of the Study:

• To develop a simplified framework for modeling allosteric multisite phosphorylation proteins.
• To demonstrate that this reduction can accurately replicate detailed multisite system behavior.
• To apply this framework to analyze a specific biological pathway.

Main Methods:

• Utilizing a single auxiliary variable to reduce model complexity.
• Comparing the reduced model's steady-state behavior with detailed models.
• Analyzing a budding yeast cell checkpoint signaling pathway.

Main Results:

• The reduced model closely replicates the steady-state behavior of detailed multisite systems.
• Optimal ultrasensitivity is achieved with concerted and redundant site activation.
• The budding yeast cell growth checkpoint exhibits a robust hysteretic switch mechanism.

Conclusions:

• The simplified framework is effective for modeling and analyzing complex biochemical systems.
• This approach facilitates the study of interacting multisite proteins.
• The budding yeast pathway demonstrates a sophisticated mechanism for cell growth measurement.