The Dependence of Actin Filament Assembly on Linking Agent Concentration

This experimental and computational study focused on the properties of actin filament bundles and networks induced by the actin filament cross-linker, $\alpha $-actinin. Structural properties of actin filament networks linked by the $\alpha $-actinin protein were studied experimentally by using confocal microscopy. We varied the concentrations of actin and linking agents to study their effects on the properties of the bundles and networks. The study showed that the molar ratio of $\alpha $-actinin to actin played an important role in the properties of the network structure, determining the branching frequency of the bundles. An experimentally guided simulation based on the $\alpha $-actinin/actin filament system was carried out using CHARMM to attempt to replicate the features of the real system and therefore to study the physics behind the actin filament assembly process in different regimes.