Differential Signaling and Tumor Necrosis Factor Receptor–Associated Factor (Traf) Degradation Mediated by Cd40 and the Epstein-Barr Virus Oncoprotein Latent Membrane Protein 1 (Lmp1)
Year: 2001
Type: article
Abstract: Latent membrane protein 1 (LMP1) plays a critical role in B cell transformation by Epstein-Barr virus (EBV) and appears to mimic a constitutively active CD40 receptor. Intracellular tumor necrosis factor (TNF) receptor-associated factor (TRAF) adapter proteins, shown to contribute to signaling by both CD40 and LMP1, were recruited by both molecules to lipid-enriched membrane rafts. However, we found that TRAFs 2 and 3 were subsequently degraded after CD40- but not LMP1-induced signaling. This degradation was proteasome-dependent and required direct TRAF binding by CD40. Using a model system designed to directly compare the signaling potency of the cytoplasmic domains of LMP1 and CD40 in B lymphocytes, we found that LMP1 more potently activates c-Jun kinase and nuclear factor kappaB and induces higher levels of several B cell effector functions than does CD40. This suggests that LMP1 utilizes a modified CD40 signaling pathway. Failure to regulate TRAFs may contribute to the enhanced capacity of LMP1 to activate B cells as well as promote B cell transformation.
Authors: Kevin D. Brown, Bruce S. Hostager, Gail A. Bishop
Institutions: University of Iowa, Iowa City VA Medical Center
Language: English
Topic: NF-κB Signaling Pathways
Subfield: Cancer Research
Domain: Life Sciences
Open Access status: bronze
OpenAlex ID: W2155110685