Rho1- and Pkc1-dependent phosphorylation of the F-BAR protein Syp1 contributes to septin ring assembly

Laura Merlini (1, 2) , Alessio Bolognesi (3) , Maria Angeles Juanes (2) , Franck Vandermoere (4) , Thibault Courtellemont (2) , Roberta Pascolutti (2) , Martial Séveno (4, 5) , Yves Barral (3) , Simonetta Piatti (2)

1 FR3487 - Fédération de Mathématiques de l'Ecole Centrale Paris
2 CRBM - Centre de recherche en Biologie cellulaire de Montpellier
3 Institute of Biochemistry
4 IGF MGX - Institut de Génomique Fonctionnelle - Montpellier GenomiX
5 BCM - BioCampus

In many cell types, septins assemble into filaments and rings at the neck of cellular appendages and/or at the cleavage furrow to help compartmentalize the plasma membrane and support cytokinesis. How septin ring assembly is coordinated with membrane re-modeling and controlled by mechanical stress at these sites is unclear. Through a genetic screen, we uncovered an unanticipated link between the conserved Rho1 GTPase and its ef-fector protein kinase C (Pkc1) with septin ring stability in yeast. Both Rho1 and Pkc1 stabilize the septin ring, at least partly through phosphorylation of the membrane-associated F-BAR protein Syp1, which colocalizes asymmetrically with the septin ring at the bud neck. Syp1 is displaced from the bud neck upon Pkc1-dependent phosphorylation at two serines, thereby affecting the rigidity of the new-forming septin ring. We propose that Rho1 and Pkc1 coordinate septin ring assembly with membrane and cell wall remodeling partly by controlling Syp1 residence at the bud neck.

Domaines: Biochimie, Biologie Moléculaire

Laura Merlini, Alessio Bolognesi, Maria Angeles Juanes, Franck Vandermoere, Thibault Courtellemont, et al.. Rho1- and Pkc1-dependent phosphorylation of the F-BAR protein Syp1 contributes to septin ring assembly. Molecular Biology of the Cell, 2015, 26 (18), pp.3245-3262. ⟨10.1091/mbc.e15-06-0366⟩. ⟨hal-01883492⟩