Septin 9 has Two Polybasic Domains Critical to Septin Filament Assembly and Golgi Integrity

Archive ouverte

Omrane, Mohyeddine | Camara, Amanda Souza | Taveneau, Cyntia | Benzoubir, Nassima | Tubiana, Thibault | Yu, Jinchao | Guérois, Raphaël | Samuel, Didier | Goud, Bruno | Poüs, Christian | Bressanelli, Stéphane | Garratt, Richard Charles | Thiam, Abdou Rachid | Gassama-Diagne, Ama

Edité par CCSD ; Elsevier -

International audience. Septins are GTP-binding proteins involved in several membrane remodeling mechanisms. They associate with membranes, presumably using a polybasic domain (PB1) that interacts with phosphoinositides (PIs). Membrane-bound septins assemble into microscopic structures that regulate membrane shape. How septins interact with PIs and then assemble and shape membranes is poorly understood. Here, we found that septin 9 has a second polybasic domain (PB2) conserved in the human septin family. Similar to PB1, PB2 binds specifically to PIs, and both domains are critical for septin filament formation. However, septin 9 membrane association is not dependent on these PB domains, but on putative PB-adjacent amphipathic helices. The presence of PB domains guarantees protein enrichment in PI-contained membranes, which is critical for PI-enriched organelles. In particular, we found that septin 9 PB domains control the assembly and functionality of the Golgi apparatus. Our findings offer further insight into the role of septins in organelle morphology.

• Description
• Sujet/Public
• Outil
• Outil d'anticipation
• Mémoire et thèse
• Gestion