Spare the Mbl, spoil the rod?

New results from Richard Daniel and Jeff Errington (University of Oxford, Oxford, UK) indicate that bacteria have different strategies to control cell shape through cell wall deposition, depending on the presence of an actin-like protein.

Distant homologues of eukaryotic actin were only recently identified in bacteria. In the rod-shaped Bacillus subtilis, these proteins, members of the MreB family, form helical cables along the cell axis and are required for the maintenance of proper cell shape. Daniel and Errington now show that MreB proteins direct the deposition of cell wall material.

The authors probed for new cell wall material in Bacillus by labeling precursors inserted into peptidoglycan (PG), the major component of the cell wall. New PG was inserted in a helical...