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Yang J, Zhao Y, Kalita M, Li X, Jamaluddin M, Tian B, Edeh CB, Wiktorowicz JE, Kudlicki A, Brasier AR. Systematic Determination of Human Cyclin Dependent Kinase (CDK)-9 Interactome Identifies Novel Functions in RNA Splicing Mediated by the DEAD Box (DDX)-5/17 RNA Helicases. Mol Cell Proteomics 2015. [PMID: 26209609 DOI: 10.1074/mcp.m115.049221] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Inducible transcriptional elongation is a rapid, stereotypic mechanism for activating immediate early immune defense genes by the epithelium in response to viral pathogens. Here, the recruitment of a multifunctional complex containing the cyclin dependent kinase 9 (CDK9) triggers the process of transcriptional elongation activating resting RNA polymerase engaged with innate immune response (IIR) genes. To identify additional functional activity of the CDK9 complex, we conducted immunoprecipitation (IP) enrichment-stable isotope labeling LC-MS/MS of the CDK9 complex in unstimulated cells and from cells activated by a synthetic dsRNA, polyinosinic/polycytidylic acid [poly (I:C)]. 245 CDK9 interacting proteins were identified with high confidence in the basal state and 20 proteins in four functional classes were validated by IP-SRM-MS. These data identified that CDK9 interacts with DDX 5/17, a family of ATP-dependent RNA helicases, important in alternative RNA splicing of NFAT5, and mH2A1 mRNA two proteins controlling redox signaling. A direct comparison of the basal versus activated state was performed using stable isotope labeling and validated by IP-SRM-MS. Recruited into the CDK9 interactome in response to poly(I:C) stimulation are HSPB1, DNA dependent kinases, and cytoskeletal myosin proteins that exchange with 60S ribosomal structural proteins. An integrated human CDK9 interactome map was developed containing all known human CDK9- interacting proteins. These data were used to develop a probabilistic global map of CDK9-dependent target genes that predicted two functional states controlling distinct cellular functions, one important in immune and stress responses. The CDK9-DDX5/17 complex was shown to be functionally important by shRNA-mediated knockdown, where differential accumulation of alternatively spliced NFAT5 and mH2A1 transcripts and alterations in downstream redox signaling were seen. The requirement of CDK9 for DDX5 recruitment to NFAT5 and mH2A1 chromatin target was further demonstrated using chromatin immunoprecipitation (ChIP). These data indicate that CDK9 is a dynamic multifunctional enzyme complex mediating not only transcriptional elongation, but also alternative RNA splicing and potentially translational control.
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Affiliation(s)
- Jun Yang
- From the ‡Department of Internal Medicine; §Sealy Center for Molecular Medicine; ¶Institute for Translational Sciences
| | - Yingxin Zhao
- From the ‡Department of Internal Medicine; §Sealy Center for Molecular Medicine; ¶Institute for Translational Sciences
| | - Mridul Kalita
- §Sealy Center for Molecular Medicine; ¶Institute for Translational Sciences
| | - Xueling Li
- ¶Institute for Translational Sciences; ‖Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas
| | - Mohammad Jamaluddin
- From the ‡Department of Internal Medicine; ¶Institute for Translational Sciences
| | - Bing Tian
- From the ‡Department of Internal Medicine; §Sealy Center for Molecular Medicine; ¶Institute for Translational Sciences
| | | | - John E Wiktorowicz
- §Sealy Center for Molecular Medicine; ¶Institute for Translational Sciences; ‖Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas
| | - Andrzej Kudlicki
- §Sealy Center for Molecular Medicine; ¶Institute for Translational Sciences; ‖Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas
| | - Allan R Brasier
- From the ‡Department of Internal Medicine; §Sealy Center for Molecular Medicine; ¶Institute for Translational Sciences;
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Fang L, Choudhary S, Zhao Y, Edeh CB, Yang C, Boldogh I, Brasier AR. ATM regulates NF-κB-dependent immediate-early genes via RelA Ser 276 phosphorylation coupled to CDK9 promoter recruitment. Nucleic Acids Res 2014; 42:8416-32. [PMID: 24957606 PMCID: PMC4117761 DOI: 10.1093/nar/gku529] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Ataxia-telangiectasia mutated (ATM), a member of the phosphatidylinositol 3 kinase-like kinase family, is a master regulator of the double strand DNA break-repair pathway after genotoxic stress. Here, we found ATM serves as an essential regulator of TNF-induced NF-kB pathway. We observed that TNF exposure of cells rapidly induced DNA double strand breaks and activates ATM. TNF-induced ROS promote nuclear IKKγ association with ubiquitin and its complex formation with ATM for nuclear export. Activated cytoplasmic ATM is involved in the selective recruitment of the E3-ubiquitin ligase β-TrCP to phospho-IκBα proteosomal degradation. Importantly, ATM binds and activates the catalytic subunit of protein kinase A (PKAc), ribosmal S6 kinase that controls RelA Ser 276 phosphorylation. In ATM knockdown cells, TNF-induced RelA Ser 276 phosphorylation is significantly decreased. We further observed decreased binding and recruitment of the transcriptional elongation complex containing cyclin dependent kinase-9 (CDK9; a kinase necessary for triggering transcriptional elongation) to promoters of NF-κB-dependent immediate-early cytokine genes, in ATM knockdown cells. We conclude that ATM is a nuclear damage-response signal modulator of TNF-induced NF-κB activation that plays a key scaffolding role in IκBα degradation and RelA Ser 276 phosphorylation. Our study provides a mechanistic explanation of decreased innate immune response associated with A-T mutation.
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Affiliation(s)
- Ling Fang
- Department of Internal Medicine, University of Texas Medical Branch (UTMB), 301 University Blvd, Galveston, TX 77555 USA Department of Biochemistry and Molecular Biology, UTMB, Galveston, TX 77555, USA
| | - Sanjeev Choudhary
- Department of Internal Medicine, University of Texas Medical Branch (UTMB), 301 University Blvd, Galveston, TX 77555 USA Sealy Center for Molecular Medicine, UTMB, 301 University Blvd, Galveston, TX 77555, USA Institute for Translational Sciences, UTMB, 301 University Blvd, Galveston, TX 77555, USA
| | - Yingxin Zhao
- Department of Internal Medicine, University of Texas Medical Branch (UTMB), 301 University Blvd, Galveston, TX 77555 USA Sealy Center for Molecular Medicine, UTMB, 301 University Blvd, Galveston, TX 77555, USA Institute for Translational Sciences, UTMB, 301 University Blvd, Galveston, TX 77555, USA
| | - Chukwudi B Edeh
- Department of Internal Medicine, University of Texas Medical Branch (UTMB), 301 University Blvd, Galveston, TX 77555 USA
| | - Chunying Yang
- Department of Radiation Oncology, Houston Methodist Research Institute, Weill Cornell University, Houston, TX 77030, USA
| | - Istvan Boldogh
- Sealy Center for Molecular Medicine, UTMB, 301 University Blvd, Galveston, TX 77555, USA Department of Microbiology and Immunology, UTMB, 301 University Blvd, Galveston, TX 77555, USA
| | - Allan R Brasier
- Department of Internal Medicine, University of Texas Medical Branch (UTMB), 301 University Blvd, Galveston, TX 77555 USA Sealy Center for Molecular Medicine, UTMB, 301 University Blvd, Galveston, TX 77555, USA Institute for Translational Sciences, UTMB, 301 University Blvd, Galveston, TX 77555, USA
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Choudhary S, Kalita M, Fang L, Patel KV, Tian B, Zhao Y, Edeh CB, Brasier AR. Inducible tumor necrosis factor (TNF) receptor-associated factor-1 expression couples the canonical to the non-canonical NF-κB pathway in TNF stimulation. J Biol Chem 2013; 288:14612-14623. [PMID: 23543740 PMCID: PMC3656313 DOI: 10.1074/jbc.m113.464081] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 03/28/2013] [Indexed: 11/06/2022] Open
Abstract
The NF-κB transcription factor mediates the inflammatory response through distinct (canonical and non-canonical) signaling pathways. The mechanisms controlling utilization of either of these pathways are largely unknown. Here we observe that TNF stimulation induces delayed NF-κB2/p100 processing and investigate the coupling mechanism. TNF stimulation induces TNF-associated factor-1 (TRAF-1) that directly binds NF-κB-inducing kinase (NIK) and stabilizes it from degradation by disrupting its interaction with TRAF2·cIAP2 ubiquitin ligase complex. We show that TRAF1 depletion prevents TNF-induced NIK stabilization and reduces p52 production. To further examine the interactions of TRAF1 and NIK with NF-κB2/p100 processing, we mathematically modeled TRAF1·NIK as a coupling signaling complex and validated computational inference by siRNA knockdown to show non-canonical pathway activation is dependent not only on TRAF1 induction but also NIK stabilization by forming TRAF1·NIK complex. Thus, these integrated computational-experimental studies of TNF-induced TRAF1 expression identified TRAF1·NIK as a central complex linking canonical and non-canonical pathways by disrupting the TRAF2-cIAP2 ubiquitin ligase complex. This feed-forward kinase pathway is essential for the activation of non-canonical pathway.
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Affiliation(s)
- Sanjeev Choudhary
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas 77555; Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas 77555; Institute for Translational Sciences, University of Texas Medical Branch, Galveston, Texas 77555.
| | - Mridul Kalita
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas 77555
| | - Ling Fang
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas 77555
| | - Kershaw V Patel
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas 77555
| | - Bing Tian
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas 77555
| | - Yingxin Zhao
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas 77555; Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas 77555; Institute for Translational Sciences, University of Texas Medical Branch, Galveston, Texas 77555
| | - Chukwudi B Edeh
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas 77555
| | - Allan R Brasier
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas 77555; Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas 77555; Institute for Translational Sciences, University of Texas Medical Branch, Galveston, Texas 77555
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Zhao Y, Tian B, Edeh CB, Brasier AR. Quantitation of the dynamic profiles of the innate immune response using multiplex selected reaction monitoring-mass spectrometry. Mol Cell Proteomics 2013; 12:1513-29. [PMID: 23418394 DOI: 10.1074/mcp.m112.023465] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The innate immune response (IIR) is a coordinated intracellular signaling network activated by the presence of pathogen-associated molecular patterns that limits pathogen spread and induces adaptive immunity. Although the precise temporal activation of the various arms of the IIR is a critical factor in the outcome of a disease, currently there are no quantitative multiplex methods for its measurement. In this study, we investigate the temporal activation pattern of the IIR in response to intracellular double-stranded RNA stimulation using a quantitative 10-plex stable isotope dilution-selected reaction monitoring-MS assay. We were able to observe rapid activation of both NF-κB and IRF3 signaling arms, with IRF3 demonstrating a transient response, whereas NF-κB underwent a delayed secondary amplification phase. Our measurements of the NF-κB-IκBα negative feedback loop indicate that about 20% of IκBα in the unstimulated cell is located within the nucleus and represents a population that is rapidly degraded in response to double-stranded RNA. Later in the time course of stimulation, the nuclear IκBα pool is repopulated first prior to its cytoplasmic accumulation. Examination of the IRF3 pathway components shows that double-stranded RNA induces initial consumption of the RIG-I PRR and the IRF3 kinase (TBK1). Stable isotope dilution-selected reaction monitoring-MS measurements after siRNA-mediated IRF3 or RelA knockdown suggests that a low nuclear threshold of NF-κB is required for inducing target gene expression, and that there is cross-inhibition of the NF-κB and IRF3 signaling arms. Finally, we were able to measure delayed noncanonical NF-κB activation by quantifying the abundance of the processed (52 kDa) NF-κB2 subunit in the nucleus. We conclude that quantitative proteomics measurement of the individual signaling arms of the IIR in response to system perturbations is significantly enabled by stable isotope dilution-selected reaction monitoring-MS-based quantification, and that this technique will reveal novel insights into the dynamics and connectivity of the IIR.
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Affiliation(s)
- Yingxin Zhao
- Institute for Translational Sciences, University of Texas Medical Branch, Galveston, Texas 77555, USA
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Zhao Y, Widen SG, Jamaluddin M, Tian B, Wood TG, Edeh CB, Brasier AR. Quantification of activated NF-kappaB/RelA complexes using ssDNA aptamer affinity-stable isotope dilution-selected reaction monitoring-mass spectrometry. Mol Cell Proteomics 2011; 10:M111.008771. [PMID: 21502374 PMCID: PMC3108844 DOI: 10.1074/mcp.m111.008771] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Revised: 04/08/2011] [Indexed: 12/12/2022] Open
Abstract
Nuclear Factor-κB (NF-κB) is a family of inducible transcription factors regulated by stimulus-induced protein interactions. In the cytoplasm, the NF-κB member RelA transactivator is inactivated by binding inhibitory IκBs, whereas in its activated state, the serine-phosphorylated protein binds the p300 histone acetyltransferase. Here we describe the isolation of a ssDNA aptamer (termed P028F4) that binds to the activated (IκBα-dissociated) form of RelA with a K(D) of 6.4 × 10(-10), and its application in an enrichment-mass spectrometric quantification assay. ssDNA P028F4 competes with cognate duplex high affinity NF-κB binding sites for RelA binding in vitro, binds activated RelA in eukaryotic nuclei and reduces TNFα-stimulated endogenous NF-κB dependent gene expression. Incorporation of P028F4 as an affinity isolation step enriches for serine 536 phosphorylated and p300 coactivator complexed RelA, simultaneously depleting IκBα·RelA complexes. A stable isotope dilution (SID)-selected reaction monitoring (SRM)- mass spectrometry (MS) assay for RelA was developed that produced a linear response over 1,000 fold dilution range of input protein and had a 200 amol lower limit of quantification. This multiplex SID-SRM-MS RelA assay was used to quantify activated endogenous RelA in cytokine-stimulated eukaryotic cells isolated by single-step P028F4 enrichment. The aptamer-SID-SRM-MS assay quantified the fraction of activated RelA in subcellular extracts, detecting the presence of a cytoplasmic RelA reservoir unresponsive to TNFα stimulation. We conclude that aptamer-SID-SRM-MS is a versatile tool for quantification of activated NF-κB/RelA and its associated complexes in response to pathway activation.
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Affiliation(s)
- Yingxin Zhao
- From the ‡Sealy Center for Molecular Medicine
- §Department of Internal Medicine
| | | | | | | | - Thomas G. Wood
- From the ‡Sealy Center for Molecular Medicine
- the ¶¶Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555
| | | | - Allan R. Brasier
- From the ‡Sealy Center for Molecular Medicine
- §Department of Internal Medicine
- ¶Institute for Translational Sciences, and
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