The latent membrane protein‐1 in Epstein‐Barr virus‐transformed lymphoblastoid cells is found with ubiquitin‐protein conjugates and heat‐shock protein 70 in lysosomes oriented around the microtubule organizing centre

Abstract

Immunofluorescence studies on Epstein-Barr virus (EBV)-transformed lymphoblastoid cells have previously shown that the latent membrane transforming protein (LMP-1) is found in patch-like inclusions which also immunostain for vimentin. We now show that EBV transformation causes a major reorganization of intermediate filaments, microtubules, mitochondria, and lysosomal elements, which generally become oriented around the microtubute organizing centre. Immunogold electron microscopy shows that LMP-1 is primarily concentrated in secondary lysosomes together with ubiquitin-protein conjugates and heat-shock protein 70. Intermediate filament inclusion formation with the above characteristics may be a general response triggered by other membrane glycoproteins; as seen, for example, in major human neurodegenerative diseases such as diffuse Lewy body disease.