Tubules, rods and spirals: diverse modes of SepF-FtsZ assembling

Abstract

AbstractZ-ring formation by FtsZ, the master assembler of divisome, is a key step in bacterial cell division. Both formation and membrane anchoring of the Z-ring requires assistance of a number of Z-ring binding proteins, such as FtsA, EzrA, SepF, SepH and ZipA. SepF participates in bundling and membrane anchoring of FtsZ in gram-positive bacteria. We reportin vitrobiophysical studies of the interactions between FtsZ and cytoplasmic component of cognate SepF from three different bacteria:Mycobacterium tuberculosis,Staphylococcus aureusandEnterococcus gallinarum.While the cytosolic domain of SepF fromM. tuberculosisis a dimer, those fromS. aureusandE. gallinarumpolymerize to form ring-like structures. Mycobacterial SepF helps in bundling of FtsZ filaments to form thick filaments and large spirals. On the other hand, ring-forming SepF from theFirmicutesbundle FtsZ into tubules.