Resolving Polarized Views: Septin Filaments Do the Twist

Septins are a highly conserved family of filamentous GTPases required for cell division in a wide range of eukaryotic organisms. In a recent issue of Nature , Vrabioiu and Mitchison use polarized fluorescence microscopy to show that septin filaments undergo a highly orchestrated rotation, from a longitudinal to circumferential orientation, coincident with splitting of the septin ring during cytokinesis ( Vrabioiu and Mitchison, 2006 ).