Physics Graduate Student Symposium

Our next session is July 31st, 2025 at 12:00 PM

ATP-Dependent Free Energy Dissipation Governs Mitotic Oscillator Precision

Liam Yourston

Fourth Year, Department of Biophysics

The precise regulation of the cell cycle during early embryonic development relies on a tightly controlled mitotic clock centered around the cyclinB-Cdk1 complex. Like information processing and many other biological processes functioning in spite of noise, the precision of a far-from-equilibrium oscillatory system like the cell cycle is energetically costly. Theoretical studies have suggested a quantitative relationship between oscillator precision and energy dissipation. Using cell-sized, water-in-oil microemulsion droplets to encapsulate Xenopus Laevis egg extracts with fully intact mitotic network components we observe self-sustained oscillations. By systematically manipulating ATP levels in each droplet, we discovered a non-monotonic response in the oscillator's speed and an increase in oscillator precision. These insights shed light on the complex coupling between the free energy budget and the mitotic oscillator performance, suggesting that an optimal energy budget is required to promote fast, yet precise mitotic cycles while constrained by energetic efficiency.

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