MapZ phosphorylation drives EzrA recruitment to the future division site of Streptococcus pneumoniae.

Abstract

MapZ dictates the positioning of FtsZ that organizes the assembly of the cell division machinery (divisome) at the midcell in Streptococcus pneumoniae. While the molecular mechanisms by which MapZ localizes to and drives the divisome at the midcell are well characterized, the role of its phosphorylation by the serine/threonine kinase StkP remains enigmatic. Here, we provide evidence that MapZ interacts with the cell division protein EzrA. We further demonstrate that this interaction is modulated by the phosphorylation of MapZ. We also show that MapZ phosphorylation influences the localization and dynamics of EzrA. We examined the localization of MapZ, EzrA, and StkP using fluorescent fusion proteins in pairwise and triplewise combinations and revealed that these proteins exhibit distinct dynamics at the division septum. Our observations support a model in which MapZ phosphorylation fine-tunes the localization and dynamics of EzrA, thereby ensuring proper cell division.