scholarly journals Epstein–Barr virus-encoded latent infection membrane protein 1 regulates the processing of p100 NF-κB2 to p52 via an IKKγ/NEMO-independent signalling pathway

Oncogene ◽  
2003 ◽  
Vol 22 (48) ◽  
pp. 7557-7569 ◽  
Author(s):  
Aristides G Eliopoulos ◽  
Jorge H Caamano ◽  
Joanne Flavell ◽  
Gary M Reynolds ◽  
Paul G Murray ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Epstein Barr Virus ◽  
Latent Infection ◽  
Signalling Pathway ◽  
Barr Virus ◽  
Epstein Barr

scholarly journals TRAF1 Is a Critical Regulator of JNK Signaling by the TRAF-Binding Domain of the Epstein-Barr Virus-Encoded Latent Infection Membrane Protein 1 but Not CD40

2003 ◽  
Vol 77 (2) ◽  
pp. 1316-1328 ◽  
Author(s):  
Aristides G. Eliopoulos ◽  
Elyse R. Waites ◽  
Sarah M. S. Blake ◽  
Clare Davies ◽  
Paul Murray ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Epstein Barr Virus ◽  
Latent Infection ◽  
Binding Domain ◽  
Cell Phenotype ◽  
Tnf Receptor ◽  
Jnk Signaling ◽  
Barr Virus ◽  
Epstein Barr ◽  
Jnk Activation

ABSTRACT The oncogenic Epstein-Barr virus (EBV)-encoded latent infection membrane protein 1 (LMP1) mimics a constitutive active tumor necrosis factor (TNF) family receptor in its ability to recruit TNF receptor-associated factors (TRAFs) and TNF receptor-associated death domain protein (TRADD) in a ligand-independent manner. As a result, LMP1 constitutively engages signaling pathways, such as the JNK and p38 mitogen-activated protein kinases (MAPK), the transcription factor NF-κB, and the JAK/STAT cascade, and these activities may explain many of its pleiotropic effects on cell phenotype, growth, and transformation. In this study we demonstrate the ability of the TRAF-binding domain of LMP1 to signal on the JNK/AP-1 axis in a cell type- dependent manner that critically involves TRAF1 and TRAF2. Thus, expression of this LMP1 domain in TRAF1-positive lymphoma cells promotes significant JNK activation, which is blocked by dominant-negative TRAF2 but not TRAF5. However, TRAF1 is absent in many established epithelial cell lines and primary nasopharyngeal carcinoma (NPC) biopsy specimens. In these cells, JNK activation by the TRAF-binding domain of LMP1 depends on the reconstitution of TRAF1 expression. The critical role of TRAF1 in the regulation of TRAF2-dependent JNK signaling is particular to the TRAF-binding domain of LMP1, since a homologous region in the cytoplasmic tail of CD40 or the TRADD-interacting domain of LMP1 signal on the JNK axis independently of TRAF1 status. These data further dissect the signaling components used by LMP1 and identify a novel role for TRAF1 as a modulator of oncogenic signals.

scholarly journals The Oncogenic Protein Kinase Tpl-2/Cot Contributes to Epstein-Barr Virus-Encoded Latent Infection Membrane Protein 1-Induced NF-κB Signaling Downstream of TRAF2

2002 ◽  
Vol 76 (9) ◽  
pp. 4567-4579 ◽  
Author(s):  
Aristides G. Eliopoulos ◽  
Clare Davies ◽  
Sarah S. M. Blake ◽  
Paul Murray ◽  
Sohrab Najafipour ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Epstein Barr Virus ◽  
Latent Infection ◽  
Cell Transformation ◽  
Adapter Protein ◽  
Growth And Survival ◽  
Barr Virus ◽  
Mediated Effects ◽  
Epstein Barr ◽  
Oncogenic Protein

ABSTRACT The Epstein-Barr virus-encoded latent infection membrane protein 1 (LMP1) is a pleiotropic protein, the activities of which include effects on cell transformation and phenotype, growth, and survival. The ability of LMP1 to mediate at least some of these phenomena could be attributed to the activation of the transcription factor NF-κB. LMP1 promotes NF-κB activation through the recruitment of the adapter protein TRAF2 and the formation of a dynamic multiprotein complex that includes the NF-κB kinase, the IκB kinases, and their downstream targets, IκBs and p105. In this study, we have identified the oncogenic kinase Tpl-2/Cot as a novel component of LMP1-induced NF-κB signaling. We show that Tpl-2 is expressed in primary biopsies from patients with nasopharyngeal carcinoma and Hodgkin's disease, where LMP1 is also found. Inducible expression of LMP1 promotes the activation of Tpl-2, and a catalytically inactive Tpl-2 mutant suppresses LMP1-induced NF-κB signaling. In colocalization and coimmunoprecipitation experiments, Tpl-2 and TRAF2 were found to interact with Tpl-2 functioning downstream of TRAF2. Consistent with this observation, catalytically inactive Tpl-2 also blocked CD40-mediated NF-κB activation, which largely depends on TRAF2. The ability of Tpl-2 to influence LMP1-induced NF-κB occurs through modulation of both IκBα and p105 functions. Furthermore, Tpl-2 was found to influence the expression of angiogenic mediators, such as COX-2 in LMP1-transfected cells. These data identify Tpl-2 as a component of LMP1 signaling downstream of TRAF2 and as a modulator of LMP1-mediated effects.

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