NOVEL BLOCKADE OF CELL-SURFACE EXPRESSION OF VIRUS GLYCOPROTEINS BY LEUCINOSTATIN-A

The nonapeptide leucinostatin A (LSA) inhibited syncytium formation wi thout profoundly affecting HN glycoprotein synthesis in Newcastle dise ase virus (NDV)-infected BHK cells. At similar doses of LSA, cytopathi c effect and infectious virus production were suppressed in vesicular stomatitis virus (VSV)-infected BHK cells. Blockade by LSA of cell sur face expression of NDV-HN and VSV-G glycoproteins was demonstrated, ac companied by intracellular accumulation of these virus glycoproteins. LSA acts as an inhibitor of mitochondrial F-type H+-translocating ATPa se, a key enzyme in the generation of ATP, but its action against cell surface expression of virus glycoproteins was independent of the depl etion of intracellular ATP. LSA also acts as an ionophore, but its act ion on intoxication by ricin and diphtheria toxin was different from t hat of monensin. This novel action of LSA is expected to be useful in investigation of the mechanism of intracellular trafficking of protein s.