Mutations which abolish phosphorylation of the TRAF-binding domain of TNF receptor 2 enhance receptor-mediated NF-kappa B activation.
We demonstrate that a 41 amino acid region (amino acids 379 to 419) in the cytoplasmic domain of tumor necrosis factor receptor 2 (TNFR2) is phosphorylated by unidentified kinase(s) both in vitro and in vivo. This domain (denoted x1c) corresponds almost exactly to the previously identified TRAF-binding domain and is by itself sufficient as a substrate for phosphorylation. In addition, the x1c domain is also crucial for TNFR2-mediated NF-kappa B activation. The cytoplasmic domain of TNFR2 lacks tyrosines, and conversion of all 12 potential serine and threonine phosphorylation targets in x1c to alanines either had no effect on NF-kappa B activation or resulted in enhanced NF-kappa B activity, depending on the structural context of x1c. The results show that while the TRAF-binding domain of TNFR2 is a major target of kinases, its phosphorylation is not required for NF-kappa B activation. Our data moreover suggest that phosphorylation of x1c negatively regulates the activation of NF-kappa B.
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PW
Institute of Molecular and Cell Biology, National University of Singapore, Republic of Singapore.
Jänicke
R U
RU
Porter
A G
AG
D000595:Amino Acid Sequence; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D015870:Gene Expression; D017930:Genes, Reporter; D008969:Molecular Sequence Data; D009154:Mutation; D016328:NF-kappa B / Q000378:metabolism*; D010449:Peptide Mapping; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D018124:Receptors, Tumor Necrosis Factor / Q000235:genetics / Q000378:metabolism*; D047889:Receptors, Tumor Necrosis Factor, Type II; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction
D015703:Antigens, CD; D016328:NF-kappa B; D018124:Receptors, Tumor Necrosis Factor; D047889:Receptors, Tumor Necrosis Factor, Type II; D011994:Recombinant Proteins; D017346:Protein Serine-Threonine Kinases