The kinase activity of Rip1 is not required for tumor necrosis factor-alpha-induced IkappaB kinase or p38 MAP kinase activation or for the ubiquitination of Rip1 by Traf2
Graduate School of Biomedical Sciences; Department of Cancer Biology
Medical Subject Headings
Animals; Antigens, CD; Apoptosis; Embryo, Mammalian; Enzyme Activation; Fibroblasts; GTPase-Activating Proteins; I-kappa B Kinase; Interleukin-6; MAP Kinase Kinase Kinases; Mice; Mice, Knockout; Mitogen-Activated Protein Kinases; NF-kappa B; Phosphorylation; Protein Processing, Post-Translational; Protein-Serine-Threonine Kinases; Proteins; Receptors, Tumor Necrosis Factor; Receptors, Tumor Necrosis Factor, Type I; TNF Receptor-Associated Factor 2; Transfection; Tumor Necrosis Factor-alpha; Ubiquitin; p38 Mitogen-Activated Protein Kinases
Life Sciences | Medicine and Health Sciences
The death domain kinase Rip1 is recruited to the tumor necrosis factor receptor type 1 and mediates the IkappaB kinase and p38 MAP kinase pathways. In response to tumor necrosis factor-alpha (TNF-alpha), we find Rip1 phosphorylated and ubiquitinated, suggesting that Rip1 phosphorylation may stimulate its ubiquitination. To address the contribution of the kinase activity of Rip1 to its ubiquitination and to TNF-alpha signaling, we introduced wild type Rip1 and a kinase-inactive form of Rip1, Rip1D138N, into rip1-/- murine embryonic fibroblast cells by retroviral infection. TNF-alpha-induced ubiquitination of Rip1 is observed in Rip1D138N cells, supporting the argument that Rip1 autophosphorylation is not required for Rip1 ubiquitination. TNF-alpha-induced Ikk and p38 MAP kinase activation is normal, and the Rip1D138N cells are resistant to TNF-alpha-induced cell death, indicating that the kinase activity of Rip1 is not required to mediate its antiapoptotic functions. In the absence of Traf2, TNF-alpha-induced ubiquitination of Rip1 is impaired, suggesting that Traf2 may be the E3 ubiquitin ligase responsible for the TNF-alpha-dependent, ubiquitination of Rip1. Finally, recruitment of the ubiquitinated Tak1 complex is dependent on the presence of Rip1, suggesting that Rip1 ubiquitination rather than its phosphorylation is critical in signaling.
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Citation: J Biol Chem. 2004 Aug 6;279(32):33185-91. Epub 2004 Jun 1. Link to article on publisher's site
The Journal of biological chemistry
Lee, Thomas H.; Shank, Jennifer; Cusson, Nicole; and Kelliher, Michelle, "The kinase activity of Rip1 is not required for tumor necrosis factor-alpha-induced IkappaB kinase or p38 MAP kinase activation or for the ubiquitination of Rip1 by Traf2" (2004). GSBS Student Publications. 670.