NF-kappaB-inducing kinase and IkappaB kinase participate in human T-cell leukemia virus I Tax-mediated NF-kappaB activation.
The tax gene product of human T-cell leukemia virus I induces aberrant expression of various cellular genes, which contributes to transformation of host cells. Induction of many Tax target genes is mediated through transcription factor NF-kappaB. Here we show that Tax triggers activation of cellular protein kinases, IkappaB kinase alpha (IKKalpha) and IKKbeta, which phosphorylate the NF-kappaB inhibitory protein IkappaB alpha, resulting in its degradation and NF-kappaB activation. Constitutive IKK activation occurs in both Tax-transfected and human T-cell leukemia virus I-infected T cells. We further demonstrate that Tax-mediated NF-kappaB signaling also requires the NF-kappaB-inducing kinase (NIK). Consistently, inactive forms of either IKKs or NIK attenuate Tax-mediated NF-kappaB activation. Therefore, Tax activates NF-kappaB by targeting cellular signaling molecules, including both IKKs and NIK.
Department of Microbiology and Immunology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA.
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Uhlik
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Good
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Xiao
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Harhaj
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Zandi
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Karin
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Sun
D002384:Catalysis; D016356:Gene Products, tax / Q000378:metabolism*; D006801:Humans; D051550:I-kappa B Kinase; D019169:Jurkat Cells; D016328:NF-kappa B / Q000378:metabolism*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D000097782:NF-kappaB-Inducing Kinase
D016356:Gene Products, tax; D051550:I-kappa B Kinase; D016328:NF-kappa B; D017346:Protein Serine-Threonine Kinases; D000097782:NF-kappaB-Inducing Kinase; C496559:CHUK protein, human; C496560:IKBKB protein, human; C496565:IKBKE protein, human