PHOSPHATIDIC-ACID FORMATION TOY PHOSPHOLIPASE-D IS REQUIRED FOR TRANSPORT FROM THE ENDOPLASMIC-RETICULUM TO THE GOLGI-COMPLEX

Background: Lipid molecules may play a regulatory role in the secretor y pathway of mammals and yeast. The lipid hydrolase phospholipase D (P LD) is one candidate for mediating regulation of secretion, based on t he location of this enzyme and its requirements for activation. Result s: We found that primary alcohols, which block formation of phosphatid ic acid (PA) by PLD, inhibited the transport of two different viral gl ycoproteins from the endoplasmic reticulum to the Golgi complex in Chi nese hamster ovary cells. Corresponding secondary alcohols, which are much less potent in blocking PA formation, were also less effective in blocking transport of the glycoproteins. The block in glycoprotein tr ansport imposed by primary alcohols was reversed when PA, in the form of liposomes, was exogenously supplied to the culture medium. Conclusi ons: We suggest that the earliest site of regulation of membrane trans port by PLD is within the intermediate compartment between the endopla smic reticulum and the Golgi complex.