Abstract
Prokaryotes contain cytoskeletal proteins such as the tubulin-like FtsZ, which forms the Z ring at the cell center for cytokinesis, and the actin-like MreB, which forms a helix along the long axis of the cell and is required for shape maintenance. Using time-lapse analysis of Escherichia coli cells expressing FtsZ-GFP, we found that FtsZ outside of the Z ring also localized in a helix-like pattern and moved very rapidly within this pattern. The movement occurred independently of the presence of Z rings and was most easily detectable in cells lacking Z rings. Moreover, we observed oscillation waves of FtsZ-GFP in the helix-like pattern, particularly in elongated cells, and the period of this oscillation was similar to that of the Min proteins. The MreB helix was not required for the rapid movement of FtsZ or the oscillation of MinD. The results suggest that FtsZ not only forms the Z ring but also is part of a highly dynamic, potentially helical cytoskeleton in bacterial cells.