title: Actin polymerization regulates clathrin coat maturation during early stages of synaptic vesicle recycling at lamprey synapses.
abstract: Although it is established that presynaptic actin participates in synaptic vesicle recycling at several synapses, the earliest stages at which actin polymerization is employed during this process are still unclear. To address this, we prevented actin polymerization at lamprey synapses by applying latrunculin B or swinholide A. Latrunculin and swinholide depolymerize actin by sequestering actin monomers and, in addition, swinholide can sever existing actin filaments. When injected into individual presynaptic axons of the intact spinal cord, fluorescently labeled monomeric actin rapidly incorporated in a calcium-dependent manner into a stable, filamentous actin network concentrated at endocytic zones. This pool of actin was disrupted completely by latrunculin. At stimulated synapses, specific disruption of actin polymerization with latrunculin and swinholide induced a selective increase in unconstricted clathrin-coated pits and, in the case of swinholide, an additional increase in the size of plasma membrane evaginations. These results indicate that actin polymerization participates initially in the maturation of clathrin-coated pits during early stages of synaptic vesicle recycling.
authors.affiliation: John B. Pierce Laboratory, Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06519,USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Bourne
authors.forename: Jennifer R
authors.initials: JR
authors.lastname: Morgan
authors.forename: Vincent A
authors.initials: VA
authors.lastname: Pieribone
mesh_terms: D008841:Actin Cytoskeleton / Q000187:drug effects / Q000378:metabolism; D000199:Actins / Q000096:biosynthesis / Q000378:metabolism*; D000818:Animals; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D022163:Clathrin-Coated Vesicles / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D004705:Endocytosis / Q000187:drug effects / Q000502:physiology; D007798:Lampreys / Q000033:anatomy & histology / Q000378:metabolism*; D008387:Marine Toxins / Q000494:pharmacology; D046529:Microscopy, Electron, Transmission; D011108:Polymers / Q000378:metabolism; D017729:Presynaptic Terminals / Q000378:metabolism* / Q000648:ultrastructure; D013116:Spinal Cord / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D013570:Synaptic Membranes / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D013572:Synaptic Vesicles / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D013844:Thiazoles / Q000494:pharmacology; D053778:Thiazolidines
chemical_list: D000199:Actins; D019086:Bridged Bicyclo Compounds, Heterocyclic; D008387:Marine Toxins; D011108:Polymers; D013844:Thiazoles; D053778:Thiazolidines; C086235:swinholide A; C037068:latrunculin B; D002118:Calcium