Controlling cell size through sizer mechanisms. Issue 5 (October 2017) - Facchetti, Giuseppe
Abstract: Cell size is partly determined through coordination between cell growth and division. How this coordination is achieved mechanistically remains mostly unknown. However, quantitative experiments together with computational modelling have reinvigorated the field and are elucidating underlying molecular processes. Size homeostasis may be achieved through different modes of regulation, including "sizers", "adders" and "timers." For sizer regulation, the cell division cycle does not proceed until a minimal size has been reached, requiring that the cell monitors its own size. Here, we highlight progress in defining sizer mechanisms in fission and budding yeasts showing how accumulation or dilution of key molecules can be used to monitor cell size during growth. We also discuss a potential role for sizers in bacterial size control. Highlights: Sizer mechanisms where cells sense their own size play a crucial role in size control. Activator accumulation model proposed for a sizer mechanism in fission yeast. Inhibitor dilution model proposed for a sizer mechanism in budding yeast. Sizer mechanisms may play a hidden role in bacterial size control.