HIGH-CONCENTRATION OF THE EBV LATENT-MEMBRANE-PROTEIN-1 IN GLYCOSPHINGOLIPID-RICH COMPLEXES FROM BOTH EPITHELIAL AND LYMPHOID-CELLS

Latent Membrane Protein 1 (LMP1) is an EBV-transforming protein which is detected both in lymphoblastoid cell lines resulting from EBV-immor talization in vitro-and in undifferentiated nasopharyngeal carcinoma ( NPC), an EBV-associated malignancy of epithelial origin. To better def ine LMP1 subcellular targets, LMP1 distribution was analyzed in cellul ar glycosphingolipid-rich complexes (GSL-complexes) derived from epith elial and lymphoid cells. These complexes are obtained by extraction o f glycosphingolipid-rich membrane domains (GSL-domains), which are clu stering sites for heterotrimeric G-proteins and G-protein-associated r eceptors. LMP1 concentration was enriched 50-fold in GSL-complexes ext racted from a NPC tumor line, C15. High concentrations of LMP1 were al so observed in GSL-complexes derived from cultured lymphoid and epithe lial cells. These data suggest that association with GSL-domains is an important step in LMP1 trafficking and is probably required for some aspects of its biological activity. (C) 1997 Academic Press.