HETEROGENEOUS DISTRIBUTION OF THE UNUSUAL PHOSPHOLIPID SEMILYSOBISPHOSPHATIDIC ACID THROUGH THE GOLGI-COMPLEX

To investigate the distribution of lipids through the Golgi complex, w e analyzed the envelopes of several viruses that assemble in different subcompartments of the Golgi, as well as subcellular fractions. Our r esults indicate that each Golgi subcompartment has a distinct phosphol ipid composition due mainly to differences in the relative amounts of semilysobisphosphatidic acid (SLBPA), sphingomyelin, phosphatidylserin e, and phosphatidylinositol. Interestingly, SLBPA is enriched in the a djacent Golgi networks compared with the Golgi stack, and this enrichm ent varies with cell type. The heterogeneous distribution of SLBPA thr ough the Golgi complex suggests it may play an important role in the s tructure and/or function of this organelle.