Nonequilibrium simulation of cytoskeletal proteins: assembly, bundling and gelation
Valerio Sorichetti (LPTMS)
Online seminar — ZOOM Meeting ID: 996 5227 7025 — Password: ask L. Mazza and D. Petrov —
The cytoskeleton of living cells is a dynamical network with an extremely rich behavior: it maintains the shape of the cell, gives it resistance to deformation, allows it to deform and migrate and provides the structure necessary for intracellular transport. In order to gain a better understanding of the biological role of the cytoskeleton, it is fundamental to understand how it assembles, how it remodels itself and which factors determines its structure.
The competition between filament bundling and elongation is one of the key factors in determining the structure and mechanical properties of the cytoskeleton. In order to capture this out-of-equilibrium process, we simulate a system of « patchy » monomers which can bind irreversibly to each other to form long filaments.
We first consider monomers which interact via a simple isotropic excluded volume interaction in addition to the patchy interaction. We study the assembly kinetics of the filaments, finding that the mean filament length increases linearly with time, and give a theoretical interpretation of this finding.
Successively, we allow the monomers to stick reversibly to each other via isotropic short-ranged interactions. We show that this simple model leads to a very rich range of different behaviors, giving rise to filaments, bundles, and complex bundle networks, depending on the thermodynamic parameters considered