Rotate into shape: MreB and bacterial morphogenesis

MreB, the bacterial actin homologue, plays a vital role in determining cell shape, but the mechanisms by which it actually functions have remained largely mysterious. Recent studies now shed new light on MreB, demonstrating that it associates with many cell-wall synthesis enzymes, including a newly identified family of proteins that mediate teichoic acid synthesis in Gram-positive bacteria. Furthermore, MreB filaments dynamically rotate around the cell circumference in a manner dependent on the cell-wall assembly machinery. Thus, MreB may function to spatially organize the enzymatic activities required for proper bacterial growth (see Figure 1).