Cell membranes exhibit a large variation in curvature. It is a common perception that curvature is caused by the activity of specific protein species. Here, we will demonstrate that it can be readily generated by various other asymmetries across the membrane, which plausibly represent a governing factor for defining shapes of membrane organelles. As a workbench for artificial cells, we employ giant unilamellar vesicles (10-100µm), which represent a suitable model system showing the response of the membrane at the cell-size scale, see Annu. Rev. Biophys. 48:93, 2019. In this talk, we will introduce approaches employing giant vesicles for the precise quantification of the membrane spontaneous curvature. Several examples for generating curvature will be considered: asymmetric distribution of ions on both sides of the membrane (Nano Lett. 18:7816, 2018), insertion/desorption of the ganglioside GM1 (PNAS 115:5756, 2018), and PEG adsorption (PNAS 108:4731, 2011; ACS Nano 10:463, 2016). We will also show how spontaneous curvature generation by protein adsorption at low surface density is able to modulate membrane morphology and topology to the extent of inducing vesicle fission (Nature Commun. 11:905, 2020). Finally, the process of membrane wetting by molecularly-crowded aqueous phases will be shown to induce vesicle budding and tubulation (Adv. Mater. Interfaces 4:1600451, 2016). Wetting by biomolecular condensates will also be discussed as means of molding the membrane (Nature Commun. 14:2809, 2023), modulating lipid organization (Nature Commun. 14:6081, 2023) and protection against poration and damage (Nature, 623:1062, 2023). The presented examples will demonstrate that even in the absence of specific proteins and/or active processes, the membrane is easily remodeled by simple physicochemical factors.

15:00: Coffee Break

15:15: Rehani Perera (C9, AG Schrul): Novel insight into the structural rearrangement of hairpin proteins during ER-to-LD partitioning

15:30: Frederic Folz (AG Morigi): Noise-induced network topologies

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