Hsp90 of E. coli modulates assembly of FtsZ, the bacterial tubulin homolog

Significance Hsp90 is a molecular chaperone that participates in protein remodeling and activation. We previously demonstrated that Hsp90 causes cell filamentation when highly expressed in E. coli . Here we show that cells filament due to overexpression of Hsp90 Ec because FtsZ, a bacterial tubulin homolog essential for cell division, fails to assemble into FtsZ rings. In vitro, Hsp90 Ec interacts with FtsZ and inhibits FtsZ polymerization. Moreover, E. coli deleted for the Hsp90 Ec gene, htpG , turn over FtsZ more rapidly than wild-type cells, and the length of Δ htpG cells is reduced compared to wild-type cells. Altogether, these results suggest that Hsp90 Ec is a modulator of cell division, and imply that the polypeptide-holding function of Hsp90 may be a biologically important chaperone activity.