Septin assemblies form by diffusion-driven annealing on membranes

142Citations
Citations of this article
193Readers
Mendeley users who have this article in their library.

Abstract

Septins assemble into filaments and higher-order structures that act as scaffolds for diverse cell functions including cytokinesis, cell polarity, and membrane remodeling. Despite their conserved role in cell organization, little is known about how septin filaments elongate and are knitted together into higher-order assemblies. Using fluorescence correlation spectroscopy, we determined that cytosolic septins are in small complexes, suggesting that septin filaments are not formed in the cytosol.When the plasma membrane of live cells is monitored by total internal reflection fluorescence microscopy, we see that septin complexes of variable size diffuse in two dimensions. Diffusing septin complexes collide and make end-on associations to form elongated filaments and higher-order structures, an assembly process we call annealing. Septin assembly by annealing can be reconstituted in vitro on supported lipid bilayers with purified septin complexes. Using the reconstitution assay, we show that septin filaments are highly flexible, grow only from free filament ends, and do not exchange subunits in the middle of filaments. This work shows that annealing is a previously unidentified intrinsic property of septins in the presence of membranes and demonstrates that cells exploit this mechanism to build large septin assemblies.

Author supplied keywords

Cite

CITATION STYLE

APA

Bridges, A. A., Zhang, H., Mehta, S. B., Occhipinti, P., Tani, T., & Gladfelter, A. S. (2014). Septin assemblies form by diffusion-driven annealing on membranes. Proceedings of the National Academy of Sciences of the United States of America, 111(6), 2146–2151. https://doi.org/10.1073/pnas.1314138111

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free