Effect of ring topology in a stochastic model for Z-ring dynamics in bacteria

Abstract

Understanding the mechanisms responsible for dynamics of the Z-ring is important for our understanding of cell division in prokaryotic cells. In this work, we present a minimal stochastic model that qualititatively reproduces observations of polymerization, of formation of dynamic contractile ring that is stable for a long time and of depolymerization shown by FtsZ polymer. We explore different mechanisms for ring breaking and hydrolysis. Hydrolysis is known to regulate the dynamics of other tubulin polymers like microtubules. We find that the presence of the ring allows for an additional mechanism for regulating the dynamics of FtsZ polymers. Ring breaking dynamics in the presence of hydrolysis naturally induce rescue and catastrophe events, irrespective of the mechanism of hydrolysis. Based on our model, we conclude that the Z-ring undergoes random breaking and closing during the process of cell division.