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bioRxiv · 10.1101/2022.12.20.521256

MODELING POLARITY SITE MOVEMENT IN YEAST VIA CALCIUM-MEDIATED REGULATION OF GAP ACTIVITY

Parikh, V.·Guan, K.
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Abstract

Symmetry-breaking polarization is a process that occurs in many cells. In budding yeast cells specifically, this polarization is possible due to the presence of a positive feedback loop, which allows for one and only one front to develop. Furthermore, in mating yeast cells the detection of pheromones plays a crucial role in the cells development of a polarity site; however, due to the microscopic size of yeast cells, there is often error in the initial polarity sites accuracy. As a result, yeast cells can correct their polarity site by allowing the GTP-Cdc42 cluster to "wander". This is typically considered as the indecisive phase of a cell. Recent studies have identified that cytosolic Ca2+ bursts, caused by sexual pheromones, increase the activity of GTPase-activating protein (GAP). This project tests this from a modeling perspective by adding a module of code to an already established positive feedback model that allows periodic spikes of GAP activity to occur. The model was successfully able to simulate the effects of calcium-mediated GAP spikes by portraying oscillating polarity sites and "wandering" polarity sites, using specific parameters based on biochemical data.

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Parikh, V., Guan, K.. 2022-12-20. MODELING POLARITY SITE MOVEMENT IN YEAST VIA CALCIUM-MEDIATED REGULATION OF GAP ACTIVITY. https://doi.org/10.1101/2022.12.20.521256

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