CtBP/BARS induces fission of Golgi membranes by acylating lysophosphatidicacid

Membrane fission is essential in intracellular transport. Acyl-coenzyme As (acyl-CoAs) are important in lipid remodelling and are required for fission of COPI-coated vesicles(1). Here we show that CtBP/BARS, a protein that fu nctions in the dynamics of Golgi tubules(2), is an essential component of t he fission machinery operating at Golgi tubular networks, including Golgi c ompartments involved in protein transport and sorting. CtBP/BARS-induced fi ssion was preceded by the formation of constricted sites in Golgi tubules, whose extreme curvature is likely to involve local changes in the membrane lipid composition. We find that CtBP/BARS uses acyl-CoA to selectively cata lyse the acylation of lysophosphatidic acid to phosphatidic acid both in pu re lipidic systems and in Golgi membranes, and that this reaction is essent ial for fission. Our results indicate a key role for lipid metabolic pathwa ys in membrane fission.