title: NIK and IKKbeta interdependence in NF-kappaB signalling--flux analysis of regulation through metabolites.
abstract: Activation of the transcription factor NF-kappaB is central to control of immune and inflammatory responses. Cytokine induced activation through the classical or canonical pathway relies on degradation of the inhibitor, IkappaBalpha and regulation by the IKKbeta kinase. In addition, the NF-kappaB is activated through the NF-kappaB-inducing kinase, NIK. Analysis of the IKK/NIK inter-relationship and its impact on NF-kappaB control, were analysed by mathematical modelling, using matrix formalism and stoichiometrically balanced reactions. The analysis considered a range of bio-reactions and core metabolites and their role in relation to kinase activation and in control of specific steps of the NF-kappaB pathway. The model predicts a growth-rate and time-dependent transfer of the primary kinase activity from IKKbeta to NIK. In addition, it suggests that NIK/IKKbeta interdependence is controlled by intermediates of phosphoribosylpyrophosphate (PRPP) within the glycolysis pathway, and thus, identifies a link between specific metabolic events and kinase activation in inflammatory signal transduction. Subsequent in vitro experiments, carried out to validate the impact of IKK/NIK interdependence, confirmed signal amplification at the level of the NF-kappaB/IkappaBalpha complex control in the presence of both kinases. Further, they demonstrate that the induced potentiation is due to synergistic enhancement of relA-dependent activation.
authors.affiliation: Academic Unit of Cell Biology, School of Biomedical Sciences, University of Sheffield, Sheffield, United Kingdom.
authors.forename: Hong-Bum
authors.initials: HB
authors.lastname: Kim
authors.forename: Iona
authors.initials: I
authors.lastname: Evans
authors.forename: Rod
authors.initials: R
authors.lastname: Smallwood
authors.forename: Mike
authors.initials: M
authors.lastname: Holcombe
authors.forename: Eva E
authors.initials: EE
authors.lastname: Qwarnstrom
mesh_terms: D015153:Blotting, Western; D002478:Cells, Cultured; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D051550:I-kappa B Kinase / Q000235:genetics / Q000378:metabolism*; D020672:I-kappa B Proteins / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D009154:Mutation; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D010754:Phosphoribosyl Pyrophosphate / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D051996:Transcription Factor RelA / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D000097782:NF-kappaB-Inducing Kinase
chemical_list: D049452:Green Fluorescent Proteins; D051550:I-kappa B Kinase; D020672:I-kappa B Proteins; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B; D010754:Phosphoribosyl Pyrophosphate; D017346:Protein Serine-Threonine Kinases; D011993:Recombinant Fusion Proteins; D051996:Transcription Factor RelA; D000097782:NF-kappaB-Inducing Kinase; C000606204:NFKBIA protein, human