Membrane binding controls ordered self-assembly of animal septins

eLife

Agata Szuba¹  Gijsje H Koenderink²  Gerard Castro-Linares²  Francois Iv³  Manos Mavrakis³  Aurélie Bertin⁴  Ralf P Richter⁵  Fouzia Bano⁵ 

[1] AMOLF, Department of Living Matter, Biological Soft Matter group, Amsterdam, Netherlands;AMOLF, Department of Living Matter, Biological Soft Matter group, Amsterdam, Netherlands;Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, Netherlands;Institut Fresnel, CNRS, Aix-Marseille Univ, Centrale Marseille, Marseille, France;Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, Paris, France;Sorbonne Université, Paris, France;School of Biomedical Sciences, Faculty of Biological Sciences, Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom;School of Physics and Astronomy, Faculty of Engineering and Physical Sciences, University of Leeds, Leeds, United Kingdom;Bragg Centre for Materials Research, University of Leeds, Leeds, United Kingdom;

关键词: plasma membrane;    cortex;    cell surface mechanics;    cytoskeleton;    D. melanogaster;    Human;   

DOI  :  10.7554/eLife.63349

来源: eLife Sciences Publications, Ltd

【 摘 要 】

Septins are conserved cytoskeletal proteins that regulate cell cortex mechanics. The mechanisms of their interactions with the plasma membrane remain poorly understood. Here, we show by cell-free reconstitution that binding to flat lipid membranes requires electrostatic interactions of septins with anionic lipids and promotes the ordered self-assembly of fly septins into filamentous meshworks. Transmission electron microscopy reveals that both fly and mammalian septin hexamers form arrays of single and paired filaments. Atomic force microscopy and quartz crystal microbalance demonstrate that the fly filaments form mechanically rigid, 12- to 18-nm thick, double layers of septins. By contrast, C-terminally truncated septin mutants form 4-nm thin monolayers, indicating that stacking requires the C-terminal coiled coils on DSep2 and Pnut subunits. Our work shows that membrane binding is required for fly septins to form ordered arrays of single and paired filaments and provides new insights into the mechanisms by which septins may regulate cell surface mechanics.

【 授权许可】

CC BY