SKM 2023 – scientific programme

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BP: Fachverband Biologische Physik

BP 8: Cell Mechanics I

BP 8.10: Talk

Tuesday, March 28, 2023, 12:30–12:45, BAR Schö

Profilin Regulating the Polymerisation Velocity of Actin — •Lina Heydenreich and Jan Kierfeld — TU Dortmund University, 44227 Dortmund, Germany

F-Actin, as a part of the cytoskeleton, drives crucial biological processes like cell motility, where the control of the polymerisation speed is essential. Experiments in [1] show a maximal polymerisation speed of F-actin at high concentrations of profilin and actin.

We present a kinetic model of F-actin growth in the presence of profilin and obtain an exact result for the mean growth velocity which is in agreement with stochastic simulations, and explains the experimental data. The maximal growth speed is limited by the release rate of profilin from filamentous actin. In the limit where nearly all actin monomers are bound to profilin, the polymerisation speed follows the Michaelis-Menten kinetics.

By analysing the presented model, we can examine the influence of an external force and the influence of profilin on the fluctuations and precision of the polymerisation. Additionally we can give constraints on the concentrations to obtain a saturation of the growth velocity.

[1] Johanna Funk et al. "Profilin and formin constitute a pacemaker system for robust actin filament growth". eLife 8 (2019), e50963