FtsK and SpoIIIE: the tale of the conserved tails.

During Bacillus subtilis sporulation, the SpoIIIE DNA translocase moves a trapped chromosome across the sporulation septum into the forespore. The preferential assembly of SpoIIIE complexes in the mother cell provided the idea that SpoIIIE functioned as a DNA exporter, which ensured translocation orientation. In this issue of Molecular Microbiology, Becker and Pogliano reinvestigate the molecular mechanisms that orient the activity of SpoIIIE. Their findings indicate that SpoIIIE reads the polarity of DNA like its Escherichia coli homologue, FtsK.