title: Single-molecule speckle analysis of actin filament turnover in lamellipodia.
abstract: 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.
authors.affiliation: Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA. naoki_watanabe@hms.harvard.edu
authors.forename: Naoki
authors.initials: N
authors.lastname: Watanabe
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Mitchison
mesh_terms: D008841:Actin Cytoskeleton / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins / Q000378:metabolism*; D000818:Animals; D001704:Biopolymers; D002460:Cell Line; D003598:Cytoskeletal Proteins; D047630:Depsipeptides; D005347:Fibroblasts; D005453:Fluorescence; D049452:Green Fluorescent Proteins; D006207:Half-Life; D008164:Luminescent Proteins; D008954:Models, Biological; D010456:Peptides, Cyclic / Q000494:pharmacology; D011554:Pseudopodia / Q000378:metabolism* / Q000648:ultrastructure; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014981:Xenopus
chemical_list: D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins; D001704:Biopolymers; D003598:Cytoskeletal Proteins; D047630:Depsipeptides; D008164:Luminescent Proteins; D010456:Peptides, Cyclic; D011993:Recombinant Fusion Proteins; C057531:jasplakinolide; D049452:Green Fluorescent Proteins