FGD4 and nasopharyngeal carcinoma: To investigate whether LMP1 affected the localization of FGD4 through protein-protein interaction, we performed subcellular fractionation using postnuclear extracts of NPC cells expressing LMP1 or the ΔTM3–6 form (Figure 5E), and performed immunofluorescence staining of FGD4 using NPC cells expressing various forms of LMP1 (Figure 6A).