The effect of termination of membrane phospholipid synthesis on cell-dependent events in Caulobacter.

Membrane phospholipid synthesis in Caulobacter crescentus has been shown to be related to the expression of specific cell cycle events. DNA synthesis was immediately inhibited if phospholipid synthesis was terminated either by glycerol starvation of a glycerol auxotroph or by treatment of mutant and wildtype cultures with cerulenin. Termination of phospholipid synthesis, by either method, resulted in the inhibition of stalk elongation, flagellum biogenesis and cell division. The inability to form a stalk appears to be directly due to the cessation of phospholipid synthesis, whereas the inhibition of flagella formation and cell division is likely a result of the secondary effect on DNA replication. Two cell cycle events, the ejection of the flagellum and stalk initiation, were shown to be independent of phospholipid synthesis and DNA replication.