title: Relaxation of Loaded ESCRT-III Spiral Springs Drives Membrane Deformation.
abstract: ESCRT-III is required for lipid membrane remodeling in many cellular processes, from abscission to viral budding and multi-vesicular body biogenesis. However, how ESCRT-III polymerization generates membrane curvature remains debated. Here, we show that Snf7, the main component of ESCRT-III, polymerizes into spirals at the surface of lipid bilayers. When covering the entire membrane surface, these spirals stopped growing when densely packed: they had a polygonal shape, suggesting that lateral compression could deform them. We reasoned that Snf7 spirals could function as spiral springs. By measuring the polymerization energy and the rigidity of Snf7 filaments, we showed that they were deformed while growing in a confined area. Furthermore, we observed that the elastic expansion of compressed Snf7 spirals generated an area difference between the two sides of the membrane and thus curvature. This spring-like activity underlies the driving force by which ESCRT-III could mediate membrane deformation and fission.
authors.affiliation: University of Geneva, Department of Biochemistry, quai Ernest Ansermet 30, 1211 Geneva 4, Switzerland.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Chiaruttini
authors.affiliation: U1006 INSERM, Aix-Marseille Université, Parc Scientifique et Technologique de Luminy, 163 avenue de Luminy, 13009 Marseille, France.
authors.forename: Lorena
authors.initials: L
authors.lastname: Redondo-Morata
authors.affiliation: University of Geneva, Department of Biochemistry, quai Ernest Ansermet 30, 1211 Geneva 4, Switzerland; Swiss National Centre for Competence in Research Programme Chemical Biology, 1211 Geneva, Switzerland; U1006 INSERM, Aix-Marseille Université, Parc Scientifique et Technologique de Luminy, 163 avenue de Luminy, 13009 Marseille, France.
authors.forename: Adai
authors.initials: A
authors.lastname: Colom
authors.affiliation: University of Geneva, Department of Biochemistry, quai Ernest Ansermet 30, 1211 Geneva 4, Switzerland.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Humbert
authors.affiliation: LPTMS,CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405 Orsay, France.
authors.forename: Martin
authors.initials: M
authors.lastname: Lenz
authors.affiliation: U1006 INSERM, Aix-Marseille Université, Parc Scientifique et Technologique de Luminy, 163 avenue de Luminy, 13009 Marseille, France. Electronic address: simon.scheuring@inserm.fr.
authors.forename: Simon
authors.initials: S
authors.lastname: Scheuring
authors.affiliation: University of Geneva, Department of Biochemistry, quai Ernest Ansermet 30, 1211 Geneva 4, Switzerland; Swiss National Centre for Competence in Research Programme Chemical Biology, 1211 Geneva, Switzerland. Electronic address: aurelien.roux@unige.ch.
authors.forename: Aurélien
authors.initials: A
authors.lastname: Roux
mesh_terms: D056827:Endosomal Sorting Complexes Required for Transport / Q000737:chemistry* / Q000648:ultrastructure*; D007425:Intracellular Membranes / Q000737:chemistry; D008051:Lipid Bilayers / Q000737:chemistry*; D008958:Models, Molecular; D057074:Virus Release; D015003:Yeasts / Q000166:cytology / Q000378:metabolism*
chemical_list: D056827:Endosomal Sorting Complexes Required for Transport; D008051:Lipid Bilayers