Septins are a conserved family of eukaryotic GTP-binding, filament-forming proteins. In Saccharomyces cerevisiae, five septins (Cdc3p, Cdc10p, Cdc11p, Cdc12p, and Shs1p) form a complex and colocalize to the incipient bud site and as a collar of filaments at the neck of budded cells. Septins serve as a scaffold to localize septin-associated proteins involved in diverse processes and as a barrier...

Septins are essential for cytokinesis in Saccharomyces cerevisiae, but their precise roles remain elusive. Currently, it is thought that before cytokinesis, the hourglass-shaped septin structure at the mother-bud neck acts as a scaffold for assembly of the actomyosin ring (AMR) and other cytokinesis factors. At the onset of cytokinesis, the septin hourglass splits to form a double ring that san...

Cyclin-dependent kinases (CDKs) regulate septin organization in a cell-cycle-dependent manner in yeast. However, the mechanism remains unclear. Here, we show that the Candida albicans CDK Cdc28 phosphorylates the Nim1-related kinase Gin4, a known septin regulator, activating its kinase activity, which in turn phosphorylates the Sep7 septin. Gin4 contains a cluster of CDK phosphorylation sites n...

Septins form a filamentous collar at the mother-bud neck in budding yeast. In cytokinesis, this collar splits into two rings and the septin complexes undergo a dramatic reorientation. Using fluorescence polarization microscopy, DeMay et al. (2011. J. Cell Biol. doi:10.1083/jcb.201012143) now demonstrate that septin complexes assemble as paired filaments in vivo and reveal new insights into sept...

The septins are a family of GTP-binding proteins that form cytoskeletal filaments. Septins are highly conserved and evolutionarily ancient but are absent from land plants. The synthetic plant cytokinin forchlorfenuron (FCF) was shown previously to inhibit budding yeast cell division and induce ectopic septin structures (M. Iwase, S. Okada, T. Oguchi, and A. Toh-e, Genes Genet. Syst. 79:199-206,...

Septins are conserved GTPases that form heteromultimeric complexes and assemble into filaments that play a critical role in cell division and polarity. Results from budding and fission yeast indicate that septin complexes form around a tetrameric core. However, the molecular structure of the core and its influence on the polarity of septin complexes and filaments is poorly defined. The septin c...

The mechanisms of the coordinated assembly and disassembly of the septin/myosin ring is central for the understanding of polar growth and cytokinesis in yeast and other organisms. The septin- and myosin-binding protein Bni5p provides a dual function during the formation and disassembly of septin/myosin rings. Early in the cell cycle, Bni5p captures Myo1p at the incipient bud site and actively t...

Septin family proteins oligomerize through guanosine 5'-triphosphate-binding domains into core heteromers, which in turn polymerize at the cleavage furrow of dividing fungal and animal cells. Septin assemblies during the interphase of animal cells remain poorly defined and are the topic of this report. In this study, we developed protocols for visualization of authentic higher-order assemblies ...

Septins are filament-forming proteins that function in cytokinesis in a wide variety of organisms. In budding yeast, the small GTPase Cdc42p triggers the recruitment of septins to the incipient budding site and the assembly of septins into a ring. We herein report that Bni1p and Cla4p, effectors of Cdc42p, are required for the assembly of the septin ring during the initiation of budding but not...