FtsK, a literate chromosome segregation machine.

The study of chromosome segregation in bacteria has gained strong insights from the use of cytology techniques. A global view of chromosome choreography during the cell cycle is emerging, highlighting as a next challenge the description of the molecular mechanisms and factors involved. Here, we review one of such factor, the FtsK DNA translocase. FtsK couples segregation of the chromosome terminus, the ter region, with cell division. It is a powerful and fast translocase that reads chromosome polarity to find the end, thereby sorting sister ter regions on either side of the division septum, and activating the last steps of segregation. Recent data have revealed the structure of the FtsK motor, how translocation is oriented by specific DNA motifs, termed KOPS, and suggests novel mechanisms for translocation and sensing chromosome polarity.