title: Regulation of synaptic vesicle budding and dynamin function by an EHD ATPase.
abstract: Eps15 homology domain-containing proteins (EHDs) are conserved ATPases implicated in membrane remodeling. Recently, EHD1 was found to be enriched at synaptic release sites, suggesting a possible involvement in the trafficking of synaptic vesicles. We have investigated the role of an EHD1/3 ortholog (l-EHD) in the lamprey giant reticulospinal synapse. l-EHD was detected by immunogold at endocytic structures adjacent to release sites. In antibody microinjection experiments, perturbation of l-EHD inhibited synaptic vesicle endocytosis and caused accumulation of clathrin-coated pits with atypical, elongated necks. The necks were covered with helix-like material containing dynamin. To test whether l-EHD directly interferes with dynamin function, we used fluid-supported bilayers as in vitro assay. We found that l-EHD strongly inhibited vesicle budding induced by dynamin in the constant presence of GTP. l-EHD also inhibited dynamin-induced membrane tubulation in the presence of GTPγS, a phenomenon linked with dynamin helix assembly. Our in vivo results demonstrate the involvement of l-EHD in clathrin/dynamin-dependent synaptic vesicle budding. Based on our in vitro observations, we suggest that l-EHD acts to limit the formation of long, unproductive dynamin helices, thereby promoting vesicle budding.
authors.affiliation: Department of Neuroscience, Karolinska Institutet, S-171 77, Stockholm, Sweden.
authors.forename: Joel
authors.initials: J
authors.lastname: Jakobsson
authors.forename: Frauke
authors.initials: F
authors.lastname: Ackermann
authors.forename: Fredrik
authors.initials: F
authors.lastname: Andersson
authors.forename: Dan
authors.initials: D
authors.lastname: Larhammar
authors.forename: Peter
authors.initials: P
authors.lastname: Löw
authors.forename: Lennart
authors.initials: L
authors.lastname: Brodin
mesh_terms: D000251:Adenosine Triphosphatases / Q000502:physiology*; D000818:Animals; D002352:Carrier Proteins / Q000502:physiology*; D034281:Dynamins / Q000502:physiology*; D005260:Female; D007798:Lampreys; D008297:Male; D017433:Protein Structure, Secondary / Q000502:physiology; D051381:Rats; D013572:Synaptic Vesicles / Q000201:enzymology / Q000502:physiology*; D033921:Vesicular Transport Proteins / Q000502:physiology*
chemical_list: D002352:Carrier Proteins; C549917:EHD1 protein, rat; C406447:EHD3 protein, human; D033921:Vesicular Transport Proteins; D000251:Adenosine Triphosphatases; D034281:Dynamins