Membrane binding controls ordered self-assembly of animal septins

• DOI: 10.7554/elife.63349
• Publication Date: 2021-04-13T12:19:00Z
• Authors: Agata Szuba; Fouzia Bano; Gerard Castro-Lin...; Francois Iv; Manos Mavrakis; Ralf P Richter; Aurélie Bertin; Gijsje H Koenderink
• Keywords: Septin; Cell Cortex; Cell membrane

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 binding to flat lipid membranes requires electrostatic septins anionic lipids and promotes ordered self-assembly fly into filamentous meshworks. Transmission electron microscopy reveals both mammalian septin hexamers form arrays single paired filaments. Atomic force quartz crystal microbalance demonstrate filaments mechanically rigid, 12- 18-nm thick, double layers septins. By contrast, C-terminally truncated mutants 4-nm thin monolayers, indicating stacking C-terminal coiled coils on DSep2 Pnut subunits. Our work shows is required for provides new insights which may surface