Regulation of synaptic vesicle budding and dynamin function by an EHD ATPase

Area of Science:

• Neuroscience
• Cell Biology
• Membrane Trafficking

Background:

• Eps15 homology domain-containing proteins (EHDs) are ATPases involved in membrane remodeling.
• EHD1's enrichment at synaptic release sites suggests a role in synaptic vesicle trafficking.
• The function of EHDs in synaptic vesicle endocytosis remains largely uncharacterized.

Purpose of the Study:

• To investigate the role of a lamprey EHD1/3 ortholog (l-EHD) in synaptic vesicle trafficking.
• To elucidate the mechanism by which l-EHD influences synaptic vesicle endocytosis and budding.

Main Methods:

• Immunogold localization of l-EHD at endocytic structures in lamprey giant reticulospinal synapse.
• Antibody microinjection to perturb l-EHD function in vivo.
• In vitro assays using fluid-supported bilayers to assess l-EHD's interaction with dynamin.

Main Results:

• l-EHD localizes to endocytic sites and its perturbation inhibits synaptic vesicle endocytosis.
• Antibody microinjection leads to accumulation of clathrin-coated pits with elongated necks containing dynamin.
• In vitro, l-EHD inhibits dynamin-induced vesicle budding and membrane tubulation.

Conclusions:

• l-EHD is involved in clathrin/dynamin-dependent synaptic vesicle budding.
• l-EHD likely promotes vesicle budding by limiting the formation of unproductive dynamin helices.
• This study provides novel insights into the regulation of synaptic vesicle recycling.