Characterization of LMP-1's association with TRAF1, TRAF2, and TRAF3.
The latent membrane protein 1 (LMP-1) of Epstein-Barr virus (EBV) contributes to the immortalizing activity of EBV in primary, human B lymphocytes. LMP-1 is targeted to the plasma membrane, where it influences signaling pathways of infected cells. LMP-1 has been found to associate with members of the tumor necrosis factor receptor-associated factor (TRAF) family of proteins. As with LMP-1, the TRAF molecules have been shown to participate in cell signaling pathways. We have characterized and mapped in detail a region of LMP-1 that associates with TRAF1, TRAF2, and TRAF3. TRAF3 alone associates with LMP-1 in a yeast two-hybrid assay, whereas all three TRAF molecules associate with LMP-1 under various conditions when they are assayed in extracts of human cells. TRAF1, TRAF2, and TRAF3 appear to associate independently with LMP-1 but bind an overlapping target site. TRAF3 associates with LMP-1 most avidly and can compete with TRAF1 and TRAF2 for binding to LMP-1. TRAF2 associates with truncated derivatives of the carboxy terminus of LMP-1 more efficiently than with the intact terminus, indicating that LMP-1's conformation may regulate its association with TRAF2. Finally, point mutations that decrease LMP-1's association with the three TRAF molecules to 3 to 20% of wild-type levels do not detectably affect otherwise intact LMP-1's induction of NF-kappaB activity. Therefore, these associations are not necessary for the majority of intact LMP-1's induction of this signaling pathway.
Sandberg
M
M
McArdle Laboratory for Cancer Research, University of Wisconsin Medical School, Madison 53706, USA.
Hammerschmidt
W
W
Sugden
B
B
D000595:Amino Acid Sequence; D001665:Binding Sites; D001667:Binding, Competitive; D019013:CD40 Antigens / Q000737:chemistry; D002460:Cell Line; D006801:Humans; D017730:Ki-1 Antigen / Q000737:chemistry; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000378:metabolism; D011485:Protein Binding; D011506:Proteins / Q000378:metabolism*; D011993:Recombinant Fusion Proteins; D012441:Saccharomyces cerevisiae; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013045:Species Specificity; D047990:TNF Receptor-Associated Factor 1; D047992:TNF Receptor-Associated Factor 2; D048008:TNF Receptor-Associated Factor 3; D014763:Viral Matrix Proteins / Q000378:metabolism*
D019013:CD40 Antigens; C037662:EBV-associated membrane antigen, Epstein-Barr virus; D017730:Ki-1 Antigen; D016328:NF-kappa B; D011506:Proteins; D011993:Recombinant Fusion Proteins; D047990:TNF Receptor-Associated Factor 1; D047992:TNF Receptor-Associated Factor 2; D048008:TNF Receptor-Associated Factor 3; D014763:Viral Matrix Proteins