MapZ marks the division sites and positions FtsZ rings in Streptococcus pneumoniae

Abstract

In every living organism, cell division requires accurate identification of the division site and placement of the division machinery. In bacteria, this process is traditionally considered to begin with the polymerization of the highly conserved tubulin-like protein FtsZ into a ring that locates precisely at midcell1. Over the last decades, several systems have been reported to regulate the spatiotemporal assembly and placement of the FtsZ-ring2-5. However, the human pathogen Streptococcus pneumoniae, as many other organisms, is devoid of these canonical systems and the mechanisms of positioning of the division machinery remain unknown4,6. Here we characterize a novel factor that locates at the division site before FtsZ and guides septum positioning in the pneumococcus. MapZ (Midcell Anchored Protein Z) forms ring structures at the cell equator and moves apart as the cell elongates, therefore behaving as a permanent beacon of division sites. MapZ then positions the FtsZ-ring through direct protein-protein interactions. MapZ-mediated control differs from previously described systems mostly based on negative regulation of FtsZ assembly. Further, MapZ is an endogenous target of the ser/thr-kinase StkP, which was recently shown to play a central role in cytokinesis and morphogenesis of the pneumococcus7-9. We show that both phosphorylated and non-phosphorylated forms of MapZ are required for proper Z-ring formation and dynamics. Altogether, this work uncovers a new mechanism for bacterial cell division that is regulated by phosphorylation and illustrates that nature has evolved a diversity of cell division mechanisms adapted to the different bacterial clades.

Minimal Peptidoglycan (PG) Turnover in Wild-Type and PG Hydrolase and Cell Division Mutants of Streptococcus pneumoniae D39 Growing Planktonically and in Host-Relevant Biofilms

“…9, left). This result was somewhat unexpected, given that MapZ has been postulated to be required for FtsZ positioning (42,85,86). Consistent with their relatively normal cell morphologies, long pulse-chase-new labeling of these cells revealed only occasional misplaced PG synthesis, which is a surrogate indicator of FtsZ location (33), in the ⌬mapZ mutant compared to that in the parent strain (Fig.…”

“…MapZ (also called LocZ) is a recently reported protein that has been hypothesized to direct FtsZ to the equators of future dividing daughter cells (42,85,86). Using FtsZ-green fluorescent protein (GFP) fusions, FtsZ was reported to be greatly mislocalized in ⌬mapZ mutants, which showed severe morphology defects (42,86). We examined ⌬mapZ cell morphologies in D39 strains labeled with FDAAs.…”

Comparative Subcellular Localization Analysis of Magnetosome Proteins Reveals a Unique Localization Behavior of Mms6 Protein onto Magnetite Crystals

“…FtsZm is a homolog of the protein FtsZ, which is related to cell division and typically shows a single-pole localization in other bacterial cells (34,35). Although the function of FtsZm was suggested to be separate from that of FtsZ in the control of cell cycle and cell division in magnetotactic bacteria (34,35), the proteins appeared to show similar localization in E. coli. MamK, a prokaryotic actin-like protein, formed filamentous structures in E. coli, as reported previously (29).…”

Chromosome segregation drives division site selection in Streptococcus pneumoniae

“…Ovococcal S. pneumoniae lacks a nucleoid occlusion system and has no Min-system (20,21). Recently, MapZ (or LocZ) was proposed to be a division site selector in S. pneumoniae (22,23). This protein localizes early at new cell division sites and positions FtsZ by a direct protein-protein interaction (22).…”