Epstein-Barr virus LMP1 induction of the epidermal growth factor receptor is mediated through a TRAF signaling pathway distinct from NF-kappaB activation.
The Epstein-Barr virus (EBV)-encoded LMP1 protein induces several cellular changes including induction of epidermal growth factor receptor (EGFR) expression and activation of the NF-kappaB transcription factor. Two domains within the carboxy terminus have been identified that activate NF-kappaB. In this study, mutational analysis of the LMP1 protein indicated that the proximal NF-kappaB activation domain, which is identical to the TRAF interaction domain (amino acids 187 to 231), is essential for induction of the EGFR. The distal NF-kappaB activation domain (amino acids 352 to 386) did not induce expression of the EGFR. In contrast, the two domains both independently activated a kappaB-CAT reporter gene and induced expression of the NF-kappaB-regulated A20 gene in C33A epithelial cells. These results indicate that induction of the EGFR by LMP1 involves the TRAF interaction domain and that activation of NF-kappaB alone is not sufficient. Northern blot analysis revealed that induction of EGFR and A20 expression is likely to be at the transcriptional level. Interestingly expression of CD40 in the C33A cells also induced expression of the EGFR. Overexpression of either TRAF3 or an amino-terminal-truncated form of TRAF3 (TRAF3-C) inhibited signaling from the LMP1 TRAF interaction domain but did not affect signaling from the distal NF-kappaB activation domain. These data further define the mechanism by which LMP1 induces expression of the EGFR and indicate that TRAF signaling from LMP1 and CD40 activates a downstream transcription pathway distinct from NF-kappaB that induces expression of the EGFR.
Miller
W E
WE
Department of Microbiology and Immunology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill 27599, USA.
Mosialos
G
G
Kieff
E
E
Raab-Traub
N
N
D000818:Animals; D001665:Binding Sites; D019013:CD40 Antigens / Q000378:metabolism; D003546:Cysteine Endopeptidases; D004268:DNA-Binding Proteins; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D004854:Herpesvirus 4, Human / Q000378:metabolism*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D016296:Mutagenesis; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger; D015398:Signal Transduction / Q000502:physiology*; D048008:TNF Receptor-Associated Factor 3; D014407:Tumor Cells, Cultured; D000072598:Tumor Necrosis Factor alpha-Induced Protein 3; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D014763:Viral Matrix Proteins / Q000235:genetics / Q000378:metabolism*
D019013:CD40 Antigens; D004268:DNA-Binding Proteins; C037662:EBV-associated membrane antigen, Epstein-Barr virus; D047908:Intracellular Signaling Peptides and Proteins; D016328:NF-kappa B; D009687:Nuclear Proteins; D011506:Proteins; D012333:RNA, Messenger; D048008:TNF Receptor-Associated Factor 3; D014409:Tumor Necrosis Factor-alpha; D014763:Viral Matrix Proteins; D066246:ErbB Receptors; C076529:TNFAIP3 protein, human; D000072598:Tumor Necrosis Factor alpha-Induced Protein 3; D003546:Cysteine Endopeptidases; C513261:Tnfaip3 protein, mouse