title: Restoration of NF-kappaB activation by tumor necrosis factor alpha receptor complex-targeted MEKK3 in receptor-interacting protein-deficient cells.
abstract: Receptor-interacting protein (RIP) plays a critical role in tumor necrosis factor alpha (TNF-alpha)-induced NF-kappaB activation. However, the mechanism by which RIP mediates TNF-alpha-induced signal transduction is not fully understood. In this study, we reconstituted RIP-deficient Jurkat T cells with a fusion protein composed of full-length MEKK3 and the death domain of RIP (MEKK3-DD). In these cells, MEKK3-DD substitutes for RIP and directly associates with TRADD in TNF receptor complexes following TNF-alpha stimulation. We found that TNF-alpha-induced NF-kappaB activation was fully restored by MEKK3-DD in these cells. In contrast, expression of a fusion protein composed of NEMO, a component of the IkappaB kinase complex, and the death domain of RIP (NEMO-DD) cannot restore TNF-alpha-induced NF-kappaB activation in RIP-deficient cells. These results indicate that the role of RIP is to specifically recruit MEKK3 to the TNF-alpha receptor complex, whereas the forced recruitment of NEMO to the TNF-alpha receptor complex is insufficient for TNF-alpha-induced NF-kappaB activation. Although MEKK2 has a high degree of homology with MEKK3, MEKK2-DD, unlike MEKK3-DD, also fails to restore TNF-alpha-induced NF-kappaB activation in RIP-deficient cells, indicating that RIP-dependent recruitment of MEKK3 plays a specific role in TNF-alpha signaling.
authors.affiliation: Department of Microbiology and Immunology, School of Medicine and Biomedical Sciences, University at Buffalo, SUNY, 138 Farber Hall, 3435 Main St., Buffalo, NY 14214, USA.
authors.forename: Marzenna
authors.initials: M
authors.lastname: Blonska
authors.forename: Yun
authors.initials: Y
authors.lastname: You
authors.forename: Romas
authors.initials: R
authors.lastname: Geleziunas
authors.forename: Xin
authors.initials: X
authors.lastname: Lin
mesh_terms: D015153:Blotting, Western; D002460:Cell Line; D024202:Electrophoretic Mobility Shift Assay; D006801:Humans; D051550:I-kappa B Kinase; D019169:Jurkat Cells; D048748:MAP Kinase Kinase Kinase 3 / Q000378:metabolism*; D008954:Models, Biological; D016328:NF-kappa B / Q000378:metabolism*; D011233:Precipitin Tests; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry / Q000378:metabolism*; D053422:Receptor-Interacting Protein Serine-Threonine Kinases; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D015398:Signal Transduction; D047988:Tumor Necrosis Factor Receptor-Associated Peptides and Proteins / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
chemical_list: D016328:NF-kappa B; D011506:Proteins; D011993:Recombinant Fusion Proteins; D047988:Tumor Necrosis Factor Receptor-Associated Peptides and Proteins; D014409:Tumor Necrosis Factor-alpha; D017346:Protein Serine-Threonine Kinases; C506249:RIPK1 protein, human; D053422:Receptor-Interacting Protein Serine-Threonine Kinases; C496559:CHUK protein, human; D051550:I-kappa B Kinase; C496560:IKBKB protein, human; C496565:IKBKE protein, human; D048748:MAP Kinase Kinase Kinase 3; C482625:MAP3K3 protein, human