Biophysical Society Thematic Meeting| Padova 2019

Quantitative Aspects of Membrane Fusion and Fission

Poster Abstracts

11-POS Board 11 CELL ADHESION REMODELLING DURING OSMOTIC PERTURBATIONS Celine Dinet 1 ; Margarita Staykova 1 ; 1 Durham University, Physics Department, Durham, United Kingdom Throughout our body, tissue cells cope with sudden changes of environmental osmotic stresses by regulating their volume and surface area. Previous studies on neurones and other cell types have shown that in response to hyperosmotic shocks membrane invaginations called vacuole like dilations (VLD’s) are formed at discrete low adhesion sites to compensate for excess plasma membrane [1]. More recent work claimed that this phenomenon is passive and involves the disruption of membrane adhesion [2]. In this work, we aim to learn about the impact of such phenomenon on the adhesion contacts remodelling and reversibility. To address this, we are using a biomimetic model system of cell to cell adhesion comprised of giant unilamellar vesicles (GUV’s) adhering to a supported lipid bilayer or to another GUV via specific biotin-neutravidin or cadherins bonds. The osmolarity of the outer medium is changed and the remodelling of the membrane as well as that of the adhesion contacts are followed using optical microscopes. We observe that the membrane adhesion contacts are pushed away from the sites of VLD formation than regenerated, and the VLD formation, size and dynamics depends on the magnitude of the stress and the adhesion density. [1] C.E.Morris et al., ‘The Invagination of Excess Surface Area by Shrinking Neurons’, Biophys J. 85(1), 223-225, (2003). [2] AJ. Kosmalaska et al., ‘Physical principle of membrane remodelling during cell mechanoadaptation’, Nat Commun. 6: 7292, (2015).

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