Actin filaments growing out from a formin-coated bead can group together into stable cables.
BLANCHOIN/ELSEVIER
Actin filaments power multiple cellular processes such as motility, morphogenesis, and polarity, but the mechanisms controlling their dynamics is poorly understood. Michelot et al. investigated the dynamics of actin building, bundling, and breakage in vitro by covering polystyrene beads with an actin filament–promoting protein called formin and then adding fluorescently labeled actin monomers.
The formin and actin monomers were enough to induce continuous actin polymerization at the surface of the bead. When an actin-severing factor called cofilin was added to the mix, filaments began to switch rapidly between elongation and shortening. The shortening always occurred...
