A conserved cell division protein directly regulates FtsZ dynamics in filamentous and unicellular actinobacteria

Abstract Bacterial cell division is driven by the polymerization of the GTPase FtsZ into a contractile structure, the so-called Z-ring. This essential process involves proteins that modulate FtsZ dynamics and hence the overall Z-ring architecture. Actinobacteria, like Streptomyces and Mycobacterium...

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Bibliographic Details
Published inbioRxiv
Main Authors Ramos-Léon, Felix, Bush, Matthew J, Sallmen, Joseph W, Chandra, Govind, Richardson, Jake, Findlay, Kim C, Mccormick, Joseph R, Schlimpert, Susan
Format Paper
LanguageEnglish
Published Cold Spring Harbor Cold Spring Harbor Laboratory Press 01.10.2020
Subjects
Cell division
Contractility
Cytokinesis
Filaments
Mycobacterium
Septum
Streptomyces
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Summary:Abstract Bacterial cell division is driven by the polymerization of the GTPase FtsZ into a contractile structure, the so-called Z-ring. This essential process involves proteins that modulate FtsZ dynamics and hence the overall Z-ring architecture. Actinobacteria, like Streptomyces and Mycobacterium lack known key FtsZ-regulators. Here we report the identification of SepH, a conserved actinobacterial protein that directly regulates FtsZ dynamics. We show that SepH is crucially involved in cell division in Streptomyces and that it binds FtsZ via a conserved helix-turn-helix motif, stimulating the assembly of FtsZ protofilaments. Comparative in vitro studies using the SepH homolog from Mycobacterium further reveal that SepH can also bundle FtsZ protofilaments, indicating an additional Z-ring stabilizing function in vivo. We propose that SepH plays a crucial role at the onset of cytokinesis in actinobacteria by promoting the rapid assembly of FtsZ filaments into division-competent Z-rings that can go on to mediate septum synthesis.
DOI:10.1101/2020.10.01.322578