Septins are a highly conserved1 family of proteins in eukaryotes required for cell division. These proteins are recognized as the fourth component of the cytoskeleton. They promote membrane remodelling by a specific phosphoinositide binding2. Consequently, septins are multi-tasking proteins and have prominent role in cytokinesis3, establishing diffusion barriers for membrane-bound proteins4, neuron morphogenesis5 and contribute to the development of neurodegenerative diseases (Alzheimer, Parkinson6) as well as tumor formation. Thus, recent years have seen renewed for the study of septins.
Septins are GTPases proteins which are bound to the inner cell membrane. As opposed to other cytoskeletal proteins, they polymerize in a non-polar fashion into paired filaments2,7. They display a remarkable plasticity, both in term of binding partners (several proteins, membranes) and self-assembly organizations. Indeed, the filaments have a potential to self-assemble into higher-order structures including rods, filaments, rings and gauzes2,7,8.
We focus our interest in understanding how septins self-assembly in distinct ultra-structures. To this end, we are using cryo-electron microscopy and tomography. Thus, we are now characterizing (i) liposome remodelling by septins (ii) septins organizations in the different ultra-structures (iii) physico-chemical conditions required for the formations of the ultra-structures and their functions (type of lipid, membrane curvature…). So far, we concentrate our study on Saccaharomyces Cerevisiae septins and recently on Drosophila Melanogaster ones, which is one of the first septins ultra-structure characterization in higher eukaryotes.
1- Pan and al “Analysis of Septins across Kingdoms Reveals Orthology and New Motifs.” BMC Evolutionary Biology 7 (2007)
2- Bertin and al “Phosphatidylinositol-4,5-Bisphosphate Promotes Budding Yeast Septin Filament Assembly and Organization.” Journal of Molecular Biology 404, no. 4 (December 10, 2010)
3- McMurray and al “Septins: Molecular Partitioning and the Generation of Cellular Asymmetry.” Cell Division 4 (2009)
4- Barral and al “Compartmentalization of the Cell Cortex by Septins Is Required for Maintenance of Cell Polarity in Yeast.” Molecular Cell 5, no. 5 (May 2000)
5- Tsang and al “Superfluous Role of Mammalian Septins 3 and 5 in Neuronal Development and Synaptic Transmission.” Molecular and Cellular Biology 28, no. 23 (December 2008)
6- Kinoshita, Makoto. “[Role of septin cytoskeleton in dopaminergic neurotransmission and neurodegeneration].” Japanese Journal of Psychopharmacology 32, no. 1 (February 2012)
7- Bertin and al “Saccharomyces Cerevisiae Septins: Supramolecular Organization of Heterooligomers and the Mechanism of Filament Assembly.” Proceedings of the National Academy of Sciences 105, no. 24 (June 17, 2008)
8- Garcia and al “Subunit-Dependent Modulation of Septin Assembly: Budding Yeast Septin Shs1 Promotes Ring and Gauze Formation.” The Journal of Cell Biology 195, no. 6 (December 12, 2011)
To cite this abstract:Cyntia Taveneau, Aurelie Di Cicco, Daniel Levy, Aurélie Bertin; Self-assembly characterization of Saccaharomyces Cerevisiae and Drosophila Melanogaster septins by cryo-electron microscopy and tomography. The 16th European Microscopy Congress, Lyon, France. https://emc-proceedings.com/abstract/self-assembly-characterization-of-saccaharomyces-cerevisiae-and-drosophila-melanogaster-septins-by-cryo-electron-microscopy-and-tomography/. Accessed: December 4, 2022
EMC Abstracts - https://emc-proceedings.com/abstract/self-assembly-characterization-of-saccaharomyces-cerevisiae-and-drosophila-melanogaster-septins-by-cryo-electron-microscopy-and-tomography/