Pushing and pulling forces by actin : from microscopic to macroscopic models. – (Serge Dmitrieff / LPT / Seminar). – 4/02/2025, 14H

Séminaire LPT

Serge Dmitrieff (Institut Jacques Monod)

Seminar LPT, 4/02/2025, 14H, 3R4, salle de conférence

Summary :
Actin networks generate large forces at the cellular scale. In this talk, we will use a combination of simulations and analytical models to understand how macroscopic mechanics emerge from microscopic elements. In particular, we will be interested in pushing forces by actin, that can reach tens of nanoNewton of magnitude in-vivo. These forces emerge from the energy gained by filament polymerization and network mechanics. We show that the growth speed and pushing force of actin networks can be predicted by scaling arguments. We will also consider contractile actin-myosin networks, such as cellular cortex. These networks are usually represented theoretically as active gels. Scaling arguments predict which forms of actin gels are good representation of actin networks – which we can verify in simulations. We can also predict how the contractile term depends on network architecture and myosin properties.