Biophysical Society Conference | Estes Park 2023

Membrane Budding and Fusion

Monday Speaker Abstracts

MOLECULAR MECHANOSENSING IN DYNAMIN-DRIVEN MEMBRANE REMODELLING

Vadim A Frolov 1 ; Javier Vera Lillo 1 ; Pedro Arrasate 1 ; Pavel V Bashkirov 2 ; 1 University of the Basque Country, Biophysics Institute, Leioa, Spain 2 Research Institute for Systems Biology and Medicine, Moscow, Russian Federation

Dynamin 1 GTPase (Dyn1) is a mechano-enzyme involved in membrane fission during synaptic vesicle endocytosis. While the overall structure of the Dyn1 fission machinery, a short helical polymer, is well understood, there is ongoing debate surrounding its operational principles. Although much of the discussion has centered around how the Dyn1 helix, driven by GTP hydrolysis, induces membrane curvature, our findings demonstrate that the GTPase activity of Dyn1 should be considered within the broader context of its integration into the membrane remodeling circuitry at the synapse. Through a series of single-molecule in vitro assays, we reveal that Dyn1 utilizes hydrolysis not only to generate membrane curvature and stress but also for mechanosensitive reassembling. Importantly, the discrimination between membrane curvature and rigidity is already encoded within subhelical Dyn1 oligomers, enabling rapid subsecond membrane fission and facilitating the prompt recycling of Dyn1 machinery for subsequent actions. This capability is crucial for supporting the high turnover of synaptic membrane required for efficient synaptic vesicle recycling.

MITOCHONDRIAL DERIVED VESICLES: A NEW MITOCHONDRIAL QUALITY CONTROL MECHANISM Chantell S. Evans ; 1 Duke University Medical Center, Cell Biology, Durham, NC, USA No Abstract

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