LMP-1 is a constitutively active Tumor Necrosis Factor Receptor analog encoded by Epstein-Barr virus. LMP-1 activation correlates with oligomerization and raft localization, but direct evidence of LMP-1 oligomers is limited. We report that LMP-1 forms multiple high molecular weight native LMP-1 complexes when analyzed by BN-PAGE, the largest of which are enriched in detergent resistant membranes.
View Article and Find Full Text PDFCyclic AMP-induced phosphorylation of the transcription factor CREB elicits expression of genes mediating diverse biological functions. In lymphoid organs, the neurotransmitter norepinephrine stimulates beta(2)-adrenergic receptors on B lymphocytes to promote CREB-dependent expression of genes like the B cell Oct 2 coactivator (OCA-B). Although CREB phosphorylation recruits cofactors such as CBP/p300 to stimulate transcription, bona fide endogenous inhibitors of CREB-coactivator or CREB-DNA interactions have not emerged.
View Article and Find Full Text PDFThe human T-cell leukemia virus-encoded oncoprotein Tax is a potent activator of viral transcription. Tax function is strictly dependent upon the cellular transcription factor CREB, and together they bind cAMP response elements within the viral promoter and mediate high-level viral transcription. Signal-dependent CREB phosphorylation at Ser(133) (pCREB) correlates with the activation of transcription.
View Article and Find Full Text PDFEpstein-Barr virus (EBV) establishes a persistent infection in the human host and is associated with a variety of human cancers. Persistent infection results from a balance between the host immune response and viral immune evasion mechanisms. EBV infection is controlled initially by the innate immune response and later by T-cell-mediated adaptive immunity.
View Article and Find Full Text PDFEpstein-Barr virus (EBV) is a human herpesvirus associated with a number of malignancies. EBV establishes a latent infection in human B cells in vitro, and infected lymphoblastoid cells proliferate indefinitely as a result of virus activation of cellular signalling pathways. Latently infected cells express a viral oncoprotein called the latent membrane protein-1 (LMP-1).
View Article and Find Full Text PDFThe latent membrane protein 1 (LMP-1) oncoprotein of Epstein-Barr virus (EBV) is a constitutively active, CD40-like cell surface signaling protein essential for EBV-mediated human B-cell immortalization. Like ligand-activated CD40, LMP-1 activates NF-kappaB and Jun kinase signaling pathways via binding, as a constitutive oligomer, to tumor necrosis factor receptor-associated factors (TRAFs). LMP-1's lipid raft association and oligomerization have been linked to its activation of cell signaling pathways.
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