title: How curvature-generating proteins build scaffolds on membrane nanotubes.
abstract: Bin/Amphiphysin/Rvs (BAR) domain proteins control the curvature of lipid membranes in endocytosis, trafficking, cell motility, the formation of complex subcellular structures, and many other cellular phenomena. They form 3D assemblies that act as molecular scaffolds to reshape the membrane and alter its mechanical properties. It is unknown, however, how a protein scaffold forms and how BAR domains interact in these assemblies at protein densities relevant for a cell. In this work, we use various experimental, theoretical, and simulation approaches to explore how BAR proteins organize to form a scaffold on a membrane nanotube. By combining quantitative microscopy with analytical modeling, we demonstrate that a highly curving BAR protein endophilin nucleates its scaffolds at the ends of a membrane tube, contrary to a weaker curving protein centaurin, which binds evenly along the tube's length. Our work implies that the nature of local protein-membrane interactions can affect the specific localization of proteins on membrane-remodeling sites. Furthermore, we show that amphipathic helices are dispensable in forming protein scaffolds. Finally, we explore a possible molecular structure of a BAR-domain scaffold using coarse-grained molecular dynamics simulations. Together with fluorescence microscopy, the simulations show that proteins need only to cover 30-40% of a tube's surface to form a rigid assembly. Our work provides mechanical and structural insights into the way BAR proteins may sculpt the membrane as a high-order cooperative assembly in important biological processes.
authors.affiliation: Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, F-75005 Paris, France; Department of Chemistry, The University of Chicago, Chicago, IL 60637; Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637; James Franck Institute, The University of Chicago, Chicago, IL 60637; Computation Institute, The University of Chicago, Chicago, IL 60637; msimunovic@rockefeller.edu patricia.bassereau@curie.fr.
authors.forename: Mijo
authors.identifier: 0000-0001-9394-1552
authors.initials: M
authors.lastname: Simunovic
authors.affiliation: Laboratory of Molecular Biology, Medical Research Council, Cambridge CB2 0QH, United Kingdom.
authors.forename: Emma
authors.initials: E
authors.lastname: Evergren
authors.affiliation: Laboratoire Charles Coulomb, UMR 5221 CNRS, Université de Montpellier, F-34095 Montpellier, France.
authors.forename: Ivan
authors.initials: I
authors.lastname: Golushko
authors.affiliation: Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, F-75005 Paris, France.
authors.forename: Coline
authors.initials: C
authors.lastname: Prévost
authors.affiliation: Chemical Biology of Membranes and Therapeutic Delivery Unit, Institut Curie, PSL Research University, CNRS UMR3666, INSERM U1143, F-75005 Paris, France.
authors.forename: Henri-François
authors.initials: HF
authors.lastname: Renard
authors.affiliation: Chemical Biology of Membranes and Therapeutic Delivery Unit, Institut Curie, PSL Research University, CNRS UMR3666, INSERM U1143, F-75005 Paris, France.
authors.forename: Ludger
authors.initials: L
authors.lastname: Johannes
authors.affiliation: Laboratory of Molecular Biology, Medical Research Council, Cambridge CB2 0QH, United Kingdom.
authors.forename: Harvey T
authors.initials: HT
authors.lastname: McMahon
authors.affiliation: Laboratoire Charles Coulomb, UMR 5221 CNRS, Université de Montpellier, F-34095 Montpellier, France.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Lorman
authors.affiliation: Department of Chemistry, The University of Chicago, Chicago, IL 60637; Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637; James Franck Institute, The University of Chicago, Chicago, IL 60637; Computation Institute, The University of Chicago, Chicago, IL 60637.
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Voth
authors.affiliation: Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, F-75005 Paris, France; Sorbonne Universités, Université Pierre et Marie Curie, Université Paris 6, F-75005, Paris, France msimunovic@rockefeller.edu patricia.bassereau@curie.fr.
authors.forename: Patricia
authors.initials: P
authors.lastname: Bassereau
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry / Q000378:metabolism; D001665:Binding Sites; D002138:Calibration; D002462:Cell Membrane / Q000737:chemistry*; D003198:Computer Simulation; D005453:Fluorescence; D008055:Lipids / Q000737:chemistry; D008565:Membrane Proteins / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D043942:Nanotubes / Q000737:chemistry*; D000072417:Protein Domains; D017433:Protein Structure, Secondary; D040681:Structural Homology, Protein; D013499:Surface Properties; D014965:X-Rays
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D008055:Lipids; D008565:Membrane Proteins
keywords: BAR proteins; endocytosis; membrane curvature; protein scaffold; self-assembly