Overexpression of EXTL3/EXTR1 enhances NF-kappaB activity induced by TNF-alpha.
EXTL3/EXTR1 is a member of the EXT gene family, which may represent a class of glycosyltransferases involved in heparan sulfate biosynthesis. It is known that heparan sulfate interacts with a variety of proteins and is therefore implicated in various cellular responses. Here, we examined the effect of EXTL3 on nuclear factor-kappaB (NF-kappaB) activity stimulated by tumor necrosis factor-alpha (TNF-alpha), one of heparin-binding cytokine. The luciferase assay demonstrated that overexpression of EXTL3 enhanced TNF-alpha-induced NF-kappaB activity. This is confirmed with an electrophoretic mobility shift assay. However, EXTL3 did not affect the CD40-mediated NF-kappaB activation. The EXTL3 mutants lacking the amino terminus region failed to enhance the activity. The fluorescence of enhanced green fluorescent protein (EGFP)-fused EXTL3 was observed at the perinuclear region, whereas, the amino terminus-truncated mutant was found in a diffuse cytoplasmic region. These results suggest that EXTL3 may modulate NF-kappaB mediated by TNF-alpha.
Laboratory of Molecular Oncology, Tsukuba Life Science Center, The Institute of Physical and Chemical Research (RIKEN), 3-1-1 Koyadai, Ibaraki, 305-0074, Tsukuba, Japan.
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D019013:CD40 Antigens / Q000378:metabolism; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D049452:Green Fluorescent Proteins; D006493:Heparin / Q000378:metabolism; D006497:Heparan Sulfate / Q000096:biosynthesis; D006801:Humans; D015151:Immunoblotting; D019656:Loss of Heterozygosity; D008156:Luciferases / Q000378:metabolism; D008164:Luminescent Proteins / Q000378:metabolism; D008856:Microscopy, Fluorescence; D009154:Mutation; D017351:N-Acetylglucosaminyltransferases; D016328:NF-kappa B / Q000378:metabolism*; D010957:Plasmids / Q000378:metabolism; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
D019013:CD40 Antigens; D049452:Green Fluorescent Proteins; D006493:Heparin; D006497:Heparan Sulfate; D008156:Luciferases; D008164:Luminescent Proteins; D017351:N-Acetylglucosaminyltransferases; D016328:NF-kappa B; D011506:Proteins; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; C110774:EXTL3 protein, human; C484685:Extl3 protein, mouse