The most abundant molecule in cell membranes is the lipid phosphatidylcholine (PC, commonly known as lecithin); accordingly, the enzymes responsible for synthesizing it are essential. Research published in the May 4 issue of the Journal of Biological Chemistry used computer simulations to gain insights into how one of these enzymes activates and shuts off PC production. These results could help researchers understand why small changes in this enzyme can lead to conditions like blindness and dwarfism.