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Single-Molecule Speckle Analysis of Actin Filament Turnover in Lamellipodia

2002; American Association for the Advancement of Science; Volume: 295; Issue: 5557 Linguagem: Inglês

10.1126/science.1067470

1095-9203

Naoki Watanabe, Timothy J. Mitchison,

Microtubule and mitosis dynamics

Lamellipodia are thin, veil-like extensions at the edge of cells that contain a dynamic array of actin filaments. We describe an approach for analyzing spatial regulation of actin polymerization and depolymerization in vivo in which we tracked single molecules of actin fused to the green fluorescent protein. Polymerization and the lifetime of actin filaments in lamellipodia were measured with high spatial precision. Basal polymerization and depolymerization occurred throughout lamellipodia with largely constant kinetics, and polymerization was promoted within one micron of the lamellipodium tip. Most of the actin filaments in the lamellipodium were generated by polymerization away from the tip.