SKM 2021 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 6: Membranes and Vesicles

BP 6.4: Vortrag

Donnerstag, 30. September 2021, 14:30–14:45, H6

Fission mechanisms of cylindrical membrane tubes — •Russell Spencer and Marcus Müller — Georg-August Universität Göttingen, Institute for Theoretical Physics, 37077 Göttingen, Germany

This work investigates the mechanisms and pathways for the fission of phospholipid membranes, in particular double-membrane fission as it occurs in mitochondrial division. We employ self-consistent field theory and utilize the string method to find the Minimum Free Energy Path (MFEP) connecting the metastable starting and ending states of different membrane topology in order to determine the most likely pathway for the transition. Our results suggest that the free energy barrier to membrane fission, as well as the dominant pathway, can be controlled by the tension experienced by the membrane. At high tension, the inner tube partially collapses into a worm-like micelle, which then ruptures, resulting in two capped tubes. The outer membrane then follows similarly. This pathway is non-leaky, i.e. the solvent inside the inner membrane, between the membranes and outside the outer membrane never mix. At lower tension, the barrier to forming a worm-like micelle becomes prohibitive, and instead, the inner and outer membranes fuse. This pathway is leaky as pores form close to the fusion sites.