ABSTRACT
The septin cytoskeleton is extensively regulated by post-translational modifications such as phosphorylation to achieve the diversity of architectures including rings, hourglass, and gauzes. While many of the phosphorylation events of septins have been extensively studied in the budding yeast Saccharomyces cerevisiae, the regulation of the kinases involved remains poorly understood. Here we show that two septin-associated kinases, the LKB1/PAR-4-related kinase Elm1 and the Nim1/PAR-1-related kinase Gin4, regulate each other at two discrete points of the cell cycle. During bud emergence, Gin4 targets Elm1 to the bud neck via direct binding and phosphorylation to control septin hourglass assembly and stability. During mitosis, Elm1 maintains Gin4 localization via direct binding and phosphorylation to enable timely remodeling of the septin hourglass into a double ring. This unique synergy ensures that septin architecture is assembled and remodeled in a temporally controlled manner to perform distinct functions during the cell cycle.
SUMMARY Marquardt et al. show that the septin-associated kinases Elm1 and Gin4 regulate each other via both direct binding and phosphorylation to control septin hourglass assembly and remodeling at different points of the cell cycle in the budding yeast Saccharomyces cerevisiae.
Competing Interest Statement
The authors have declared no competing interest.
ABBREVIATIONS
- GBP
- GFP nanobody binding peptide
- HDR
- hourglass to double ring
- IR
- inter-region
- KA1
- kinase associated 1
- KD
- kinase dead
- LC-MS
- liquid chromatography mass spectrometry
- PAK
- p21-activated protein kinase
- SAP
- septin-associated protein
- SC
- Synthetic complete minimal media
- SUMO
- small ubiquitin-like modifier
