Modelling and Inferring Protein Dynamics in Fission Yeast Mechanosensing*

Mechanical forces play an important role in determining the growth and the shape of a cell, yet they can also be a potential cause of damage. Indeed, cells are endowed with mechanosensors, i.e. receptors at the subcellular scale able to detect mechanical stimuli. In fission yeast, the transmembrane protein Wsc1 is such a mechanosensory. It stimulates glucan synthesis to reinforce the cell wall, the protective thin layer that surrounds the cell. Interestingly, Wsc1 clusters in the region of the cell wall where stress is applied. 

This work aims at describing clustering by building a mathematical model based on reaction-diffusion equations that take into account the interactions between cell wall polysaccharides and Wsc1. To quantify the dynamical parameters of this model, we developed a new inference method for Fluorescence Recovery after Photobleaching (FRAP) experiments which only requires minimal hypotheses. Thanks to the flexibility of this method, it is possible to carry out the experiment with the Wsc1 protein as the cell wall is under compression and obtain accurate protein mobility estimations as a function of mechanical stress.

This study offers fresh methodologies for quantifying and comprehending intricate protein dynamics within cells and tissues.