The FtsH protein accumulates at the septum of Bacillus subtilis during cell division and sporulation

The ftsH gene encodes an ATP- and Zn2+-dependent metalloprotease which is a nchored to the cytoplasmic membrane via two transmembrane segments in such a way that the very short amino- and the long carboxy termini are exposed t o the cytoplasm. Deletion of the ftsH gene in Bacillus subtilis results in a pleiotropic phenotype such as filamentous growth. This observation prompt ed us to ask whether ftsH is involved in cell division. A translational fus ion was constructed between the complete coding region of ftsH and gfp(+) t he latter carrying five point mutations to obtain enhanced fluorescence. We detected that the FtsH protein accumulates in the midcell septum of dividi ng cells, and during sporulation first in the asymmetrically located septa of sporulating cells and later in the membrane which engulfs the forespore. These observations revealed a new function of FtsH.