Membrane binding controls ordered self-assembly of animal septins
- University of Leeds, United Kingdom
- Umeå Universitet, Sweden
- Delft University of Technology, Netherlands
- Aix-Marseille Univ, France
- Institut Curie, France
Abstract
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.
Data availability
All data generated or analysed during this study are included in the manuscript and supporting files.
Article and author information
Author details
Gijsje H Koenderink
Funding
H2020 European Research Council (ERC StG 335672,MINICELL)
- Gijsje H Koenderink
H2020 European Research Council (ERC StG 306435; JELLY)
- Ralf P Richter
Biotechnology and Biological Sciences Research Council (Equipment grant BB/R000174/1)
- Ralf P Richter
Agence Nationale de la Recherche (ANR-13-JSV8-0002-01)
- Manos Mavrakis
- Aurélie Bertin
Agence Nationale de la Recherche (ANR-17-CE13-0014)
- Manos Mavrakis
- Aurélie Bertin
Fondation ARC pour la Recherche sur le Cancer (PJA 20151203182)
- Manos Mavrakis
- Aurélie Bertin
Nederlandse Organisatie voor Wetenschappelijk Onderzoek (024.003.019)
- Gijsje H Koenderink
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2021, Szuba et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Membrane binding controls ordered self-assembly of animal septins
eLife 10:e63349.
https://doi.org/10.7554/eLife.63349
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