Reining in cytokinesis with a septin corral

Septins are a family of conserved GTP-binding proteins that function in cytokinesis in fungi and animals. In budding yeast, septins form scaffolds for assembly of the actomyosin contractile ring at the cleavage plane, a role that does not appear to be conserved in other organisms. The septins form an hourglass-shaped collar at the mother-bud neck, which splits into two rings flanking the division plane at cytokinesis. A recent study((1)) demonstrates that these two septin rings constitute diffusion barriers that create a cytokinetic compartment to retain cortical cytokinetic factors in proximity to the cleavage plane. (C) 2004 Wiley Periodicals, Inc.