The Fn14 cytoplasmic tail binds tumour-necrosis-factor-receptor-associated factors 1, 2, 3 and 5 and mediates nuclear factor-kappaB activation.
Fn14 is a growth-factor-inducible immediate-early-response gene encoding a 102-amino-acid type I transmembrane protein. The human Fn14 protein was recently identified as a cell-surface receptor for the tumour necrosis factor (TNF) superfamily member named TWEAK (TNF-like weak inducer of apoptosis). In the present paper, we report that the human TWEAK extracellular domain can also bind the murine Fn14 protein. Furthermore, site-specific mutagenesis and directed yeast two-hybrid interaction assays revealed that the TNFR-associated factor (TRAF) 1, 2, 3 and 5 adaptor molecules bind the murine Fn14 cytoplasmic tail at an overlapping, but non-identical, amino acid sequence motif. We also found that TWEAK treatment of quiescent NIH 3T3 cells stimulates inhibitory kappaBalpha phosphorylation and transcriptional activation of a nuclear factor-kappaB (NF-kappaB) enhancer/luciferase reporter construct. Fn14 overexpression in transiently transfected NIH 3T3 cells also promotes NF-kappaB activation, and this cellular response requires an intact TRAF binding site. These results indicate that Fn14 is a functional TWEAK receptor that can associate with four distinct TRAF family members and stimulate the NF-kappaB transcription factor signalling pathway.
Pubmed ID: 12529173 RIS Download
3T3 Cells | Animals | Apoptosis Regulatory Proteins | Binding Sites | Carrier Proteins | Cell Line | Cloning, Molecular | Cytoplasm | Genes, Reporter | Genetic Vectors | Humans | Luciferases | MAP Kinase Signaling System | Membrane Proteins | Mice | NF-kappa B | Plasmids | Protein Binding | Proteins | Receptors, Tumor Necrosis Factor | Saccharomyces cerevisiae | Spodoptera | TNF Receptor-Associated Factor 1 | TNF Receptor-Associated Factor 2 | TNF Receptor-Associated Factor 3 | TNF Receptor-Associated Factor 5 | Transfection | Tumor Necrosis Factors