PlsX is a central enzyme of phospholipid synthesis in bacteria, converting acyl-ACP to acyl-phosphate on the pathway to phosphatidic acid formation. PlsX has received attention because it plays a key role in the coordination of fatty acid and phospholipid synthesis. Recently, PlsX was also suggested to coordinate membrane synthesis with cell division inBacillus subtilis. Here, we have re-investigated the cell biology of PlsX and determined that the enzyme is uniformly distributed on the membrane of most cells, but occasionally appears as membrane foci as well. Foci and homogenous patterns seem freely interconvertible but the prevalence of the uniform staining suggests that PlsX does not need to localize to specific sites to function correctly. We also investigated the relationship between PlsX and the divisome. In contrast to previous observations, PlsX's foci showed no obvious periodicity of localization and did not colocalize with the divisome. Furthermore, depletion of PlsX did not affect cell division if phospholipid synthesis is maintained by an alternative enzyme. These results suggest that coordination between division and membrane synthesis may not require physical or functional interactions between the divisome and phospholipid synthesis enzymes.
We have re-investigated the localization of PlsX, a central enzyme in phospholipid synthesis of Bacillus subtilis. We determined that PlsX is uniformly distributed on the membrane of cells, but occasionally appears as motile membrane foci as well. PlsX does not colocalize with the divisome and the depletion of PlsX does not affect Z-ring formation if phospholipid synthesis is maintained. Thus, coordination between membrane synthesis and cell division may not involve an interaction between both machineries.