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Cardiomyocyte-specific regression of nitrosative stress-mediated S-Nitrosylation of IKKγ alleviates pathological cardiac hypertrophy. Cell Signal 2022; 98:110403. [PMID: 35835332 DOI: 10.1016/j.cellsig.2022.110403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 06/21/2022] [Accepted: 07/07/2022] [Indexed: 11/21/2022]
Abstract
IKKγ prototypically promotes NFκBp65 activity by regulating the assembly of the IKK holocomplex. In hypertrophied cardiomyocytes, the p65-p300 complex-induced regenerative efforts are neutralized by the p53-p300 complex-mediated apoptotic load resulting in compromised cardiac function. The present study reports that nitrosative stress leads to S-Nitrosylation of IKKγ in hypertrophied cardiomyocytes in a pre-clinical model. Using a cardiomyocyte-targeted nanoconjugate, IKKγ S-Nitrosylation-resistant mutant plasmids were delivered to the pathologically hypertrophied heart that resulted in improved cardiac function by amelioration of cardiomyocyte apoptosis and simultaneous induction of their cell cycle re-entry machinery. Mechanistically, in IKKγ S-Nitrosyl mutant-transfected hypertrophied cells, increased IKKγ-p300 binding downregulated the binding of p53 and p65 with p300. This shifted the binding preference of p65 from p300 to HDAC1 resulting in upregulated expression of cyclin D1 and CDK2 via the p27/pRb pathway. This approach has therapeutic advantage over mainstream anti-hypertrophic remedies which concomitantly reduce the regenerative prowess of resident cardiomyocytes during hypertrophy upon downregulation of myocyte apoptosis. Therefore, cardiomyocyte-targeted delivery of IKKγ S-Nitrosyl mutants during hypertrophy can be exploited as a novel strategy to re-muscularize the diseased heart.
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Häfner S. Binding Nemo. Microbes Infect 2020; 23:S1286-4579(20)30184-2. [PMID: 33470213 DOI: 10.1016/j.micinf.2020.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 10/15/2020] [Indexed: 10/23/2022]
Abstract
Article highlight based on "SNW1 interacts with IKKγ to positively regulate antiviral innate immune responses against influenza A virus infection" by Qiao et al.
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Affiliation(s)
- Sophia Häfner
- University of Copenhagen, BRIC Biotech, Research & Innovation Centre, Lund Group, 2200, Copenhagen, Denmark.
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3
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Ko HJ, Jo YH, Patnaik BB, Park KB, Kim CE, Keshavarz M, Jang HA, Lee YS, Han YS. IKKγ/NEMO Is Required to Confer Antimicrobial Innate Immune Responses in the Yellow Mealworm, Tenebrio Molitor. Int J Mol Sci 2020; 21:ijms21186734. [PMID: 32937897 PMCID: PMC7555931 DOI: 10.3390/ijms21186734] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 08/31/2020] [Accepted: 09/07/2020] [Indexed: 12/14/2022] Open
Abstract
IKKγ/NEMO is the regulatory subunit of the IκB kinase (IKK) complex, which regulates the NF-κB signaling pathway. Within the IKK complex, IKKγ/NEMO is the non-catalytic subunit, whereas IKKα and IKKβ are the structurally related catalytic subunits. In this study, TmIKKγ was screened from the Tenebrio molitor RNA-Seq database and functionally characterized using RNAi screening for its role in regulating T. molitor antimicrobial peptide (AMP) genes after microbial challenges. The TmIKKγ transcript is 1521 bp that putatively encodes a polypeptide of 506 amino acid residues. TmIKKγ contains a NF-κB essential modulator (NEMO) and a leucine zipper domain of coiled coil region 2 (LZCC2). A phylogenetic analysis confirmed its homology to the red flour beetle, Tribolium castaneum IKKγ (TcIKKγ). The expression of TmIKKγ mRNA showed that it might function in diverse tissues of the insect, with a higher expression in the hemocytes and the fat body of the late-instar larvae. TmIKKγ mRNA expression was induced by Escherichia coli, Staphylococcus aureus, and Candida albicans challenges in the whole larvae and in tissues such as the hemocytes, gut and fat body. The knockdown of TmIKKγ mRNA significantly reduced the survival of the larvae after microbial challenges. Furthermore, we investigated the tissue-specific induction patterns of fourteen T. molitor AMP genes in TmIKKγ mRNA-silenced individuals after microbial challenges. In general, the mRNA expression of TmTenecin1, -2, and -4; TmDefensin1 and -2; TmColeoptericin1 and 2; and TmAttacin1a, 1b, and 2 were found to be downregulated in the hemocytes, gut, and fat body tissues in the TmIKKγ-silenced individuals after microbial challenges. Under similar conditions, TmRelish (NF-κB transcription factor) mRNA was also found to be downregulated. Thus, TmIKKγ is an important factor in the antimicrobial innate immune response of T. molitor.
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Affiliation(s)
- Hye Jin Ko
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Korea; (H.J.K.); (Y.H.J.); (K.B.P.); (C.E.K.); (M.K.); (H.A.J.)
| | - Yong Hun Jo
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Korea; (H.J.K.); (Y.H.J.); (K.B.P.); (C.E.K.); (M.K.); (H.A.J.)
| | - Bharat Bhusan Patnaik
- School of Biotech Sciences, Trident Academy of Creative Technology (TACT), Chandrasekharpur, Bhubaneswar, Odisha 751024, India;
- P.G. Department of Bio-Sciences and Bio-Technology, Fakir Mohan University, Nuapadhi, Balasore, Odisha 756089, India
| | - Ki Beom Park
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Korea; (H.J.K.); (Y.H.J.); (K.B.P.); (C.E.K.); (M.K.); (H.A.J.)
| | - Chang Eun Kim
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Korea; (H.J.K.); (Y.H.J.); (K.B.P.); (C.E.K.); (M.K.); (H.A.J.)
| | - Maryam Keshavarz
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Korea; (H.J.K.); (Y.H.J.); (K.B.P.); (C.E.K.); (M.K.); (H.A.J.)
| | - Ho Am Jang
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Korea; (H.J.K.); (Y.H.J.); (K.B.P.); (C.E.K.); (M.K.); (H.A.J.)
| | - Yong Seok Lee
- School of Biotechnology and Life Sciences, College of Natural Sciences, Soonchunhyang University, 22 Soonchunhyangro, Shinchang-Myeon, Asan, Chungchungnam-do 31538, Korea;
| | - Yeon Soo Han
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Korea; (H.J.K.); (Y.H.J.); (K.B.P.); (C.E.K.); (M.K.); (H.A.J.)
- Correspondence: ; Tel.: +82-62-530-2072
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4
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Gadi N, Wu SC, Spihlman AP, Moulton VR. What's Sex Got to Do With COVID-19? Gender-Based Differences in the Host Immune Response to Coronaviruses. Front Immunol 2020; 11:2147. [PMID: 32983176 PMCID: PMC7485092 DOI: 10.3389/fimmu.2020.02147] [Citation(s) in RCA: 100] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 08/07/2020] [Indexed: 01/08/2023] Open
Abstract
The novel severe acute respiratory syndrome coronavirus 2, the cause of the coronavirus disease 2019 (COVID-19) pandemic, has ravaged the world, with over 22 million total cases and over 770,000 deaths worldwide as of August 18, 2020. While the elderly are most severely affected, implicating an age bias, a striking factor in the demographics of this deadly disease is the gender bias, with higher numbers of cases, greater disease severity, and higher death rates among men than women across the lifespan. While pre-existing comorbidities and social, behavioral, and lifestyle factors contribute to this bias, biological factors underlying the host immune response may be crucial contributors. Women mount stronger immune responses to infections and vaccinations and outlive men. Sex-based biological factors underlying the immune response are therefore important determinants of susceptibility to infections, disease outcomes, and mortality. Despite this, gender is a profoundly understudied and often overlooked variable in research related to the immune response and infectious diseases, and it is largely ignored in drug and vaccine clinical trials. Understanding these factors will not only help better understand the pathogenesis of COVID-19, but it will also guide the design of effective therapies and vaccine strategies for gender-based personalized medicine. This review focuses on sex-based differences in genes, sex hormones, and the microbiome underlying the host immune response and their relevance to infections with a focus on coronaviruses.
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Affiliation(s)
- Nirupa Gadi
- Division of Rheumatology and Clinical Immunology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
- School of Medicine, Boston University, Boston, MA, United States
| | - Samantha C. Wu
- Division of Rheumatology and Clinical Immunology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
- School of Medicine, Boston University, Boston, MA, United States
| | - Allison P. Spihlman
- Division of Rheumatology and Clinical Immunology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
- School of Medicine, Boston University, Boston, MA, United States
| | - Vaishali R. Moulton
- Division of Rheumatology and Clinical Immunology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
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Placental Expression of NEMO Protein in Normal Pregnancy and Preeclampsia. DISEASE MARKERS 2019; 2019:8418379. [PMID: 30723530 PMCID: PMC6339720 DOI: 10.1155/2019/8418379] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Revised: 10/24/2018] [Accepted: 11/11/2018] [Indexed: 12/13/2022]
Abstract
Background Preeclamptic pregnancies often present an intensified inflammatory state associated with the nuclear activity of NFκB. NEMO is an essential regulator of nuclear factor kappa B (NFκB) in cytoplasmic and nuclear cellular compartments. The aim of the present study is to examine the level and localization of the NEMO protein in preeclamptic and nonpreeclamptic placentas. Methods The study includes 97 preeclamptic cases and 88 controls. NEMO distribution was analyzed immunohistochemically. Its localization in the nuclear and cytoplasmic fractions, as well as in total homogenates of placental samples, was studied by western blot and ELISA. Results The western blot and ELISA results indicate a significant difference in NEMO concentration in the total and nuclear fractions between preeclamptic and control samples (p < 0.01 and p < 0.001, respectively). In the cytoplasmic complement, similar levels of NEMO were found in preeclamptic and control placentas. In addition, immunohistochemical staining revealed that the NEMO protein is mainly localized in the syncytiotrophoblast layer, with controls demonstrating a stronger reaction with NEMO antibodies. This study also shows that the placental level of NEMO depends on the sex of the fetus. Conclusions The depletion of the NEMO protein in the cellular compartments of placental samples may activate one of the molecular pathways influencing the development of preeclampsia, especially in pregnancies with a female fetus. A reduction of the NEMO protein in the nuclear fraction of preeclamptic placentas may intensify the inflammatory state characteristic for preeclampsia and increase the level of apoptosis and necrosis within preeclamptic placentas.
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Fisher MR, Rivera-Reyes A, Bloch NB, Schatz DG, Bassing CH. Immature Lymphocytes Inhibit Rag1 and Rag2 Transcription and V(D)J Recombination in Response to DNA Double-Strand Breaks. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2017; 198:2943-2956. [PMID: 28213501 PMCID: PMC5360515 DOI: 10.4049/jimmunol.1601639] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 01/16/2017] [Indexed: 12/26/2022]
Abstract
Mammalian cells have evolved a common DNA damage response (DDR) that sustains cellular function, maintains genomic integrity, and suppresses malignant transformation. In pre-B cells, DNA double-strand breaks (DSBs) induced at Igκ loci by the Rag1/Rag2 (RAG) endonuclease engage this DDR to modulate transcription of genes that regulate lymphocyte-specific processes. We previously reported that RAG DSBs induced at one Igκ allele signal through the ataxia telangiectasia mutated (ATM) kinase to feedback-inhibit RAG expression and RAG cleavage of the other Igκ allele. In this article, we show that DSBs induced by ionizing radiation, etoposide, or bleomycin suppress Rag1 and Rag2 mRNA levels in primary pre-B cells, pro-B cells, and pro-T cells, indicating that inhibition of Rag1 and Rag2 expression is a prevalent DSB response among immature lymphocytes. DSBs induced in pre-B cells signal rapid transcriptional repression of Rag1 and Rag2, causing downregulation of both Rag1 and Rag2 mRNA, but only Rag1 protein. This transcriptional inhibition requires the ATM kinase and the NF-κB essential modulator protein, implicating a role for ATM-mediated activation of canonical NF-κB transcription factors. Finally, we demonstrate that DSBs induced in pre-B cells by etoposide or bleomycin inhibit recombination of Igκ loci and a chromosomally integrated substrate. Our data indicate that immature lymphocytes exploit a common DDR signaling pathway to limit DSBs at multiple genomic locations within developmental stages wherein monoallelic Ag receptor locus recombination is enforced. We discuss the implications of our findings for mechanisms that orchestrate the differentiation of monospecific lymphocytes while suppressing oncogenic Ag receptor locus translocations.
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Affiliation(s)
- Megan R Fisher
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA 19104
- Immunology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104
- Department of Pathology and Laboratory Medicine, Abramson Family Cancer Research Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104
| | - Adrian Rivera-Reyes
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA 19104
- Department of Pathology and Laboratory Medicine, Abramson Family Cancer Research Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104
- Cancer Biology Program of the Cell and Molecular Biology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104; and
| | - Noah B Bloch
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA 19104
| | - David G Schatz
- Department of Immunobiology, Yale University School of Medicine, Howard Hughes Medical Institute, New Haven, CT 06520
| | - Craig H Bassing
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA 19104;
- Immunology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104
- Department of Pathology and Laboratory Medicine, Abramson Family Cancer Research Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104
- Cancer Biology Program of the Cell and Molecular Biology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104; and
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7
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Sakowicz A, Hejduk P, Pietrucha T, Nowakowska M, Płuciennik E, Pospiech K, Gach A, Rybak-Krzyszkowska M, Sakowicz B, Kaminski M, Krasomski G, Biesiada L. Finding NEMO in preeclampsia. Am J Obstet Gynecol 2016; 214:538.e1-538.e7. [PMID: 26571191 DOI: 10.1016/j.ajog.2015.11.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 10/24/2015] [Accepted: 11/05/2015] [Indexed: 11/19/2022]
Abstract
BACKGROUND The mechanism of preeclampsia and its way of inheritance are still a mystery. Biochemical and immunochemical studies reveal a substantial increase in tumor necrosis factor alpha, interleukin-1 beta, and interleukin-6 concentrations in the blood of women with preeclampsia. The level of these factors is regulated by nuclear facxtor-kappa B, whose activation in a classical pathway requires inhibitory kappa B kinase gamma (known as NEMO or IKBKG). Moreover, NEMO can schedule between cytoplasma and the nucleus. In the nucleus, IKBKG interacts with other proteins, and thus, it is implicated in the regulation of different gene expressions, which are related to cell cycle progression, proliferation, differentiation, and apoptosis. OBJECTIVE This is the first study investigating the association between the level of NEMO gene expression and the presence of preeclampsia. We tested the hypothesis that the simultaneous increase in NEMO gene expression both in the mother and her fetus may be responsible for the preeclampsia development. Moreover, the relationships between clinical risk factors of preeclampsia and the levels of NEMO gene expression in blood, umbilical cord blood, and placentas were investigated. STUDY DESIGN A total of 91 women (43 preeclamptic women and 48 controls) and their children were examined. Real-time reverse transcription-polymerase chain reaction was used to assess the amount total NEMO messenger ribonucleic acid (mRNA) content and the mRNA level of each NEMO transcript from exons 1A, 1B, and 1C in maternal blood, umbilical cord blood, and placentas. Univariate analyses and correlation tests were performed to examine the association between NEMO gene expression and preeclampsia. RESULTS Newborn weight and height, maternal platelet number, and gestational age (week of delivery) were lower in the group of women with preeclampsia than controls. NEMO gene expression level was found to be almost 7 times higher in the group of women with preeclampsia than healthy controls. The correlation analysis found that a simultaneous increase in the expression level of total NEMO mRNA in maternal blood and the mRNA for total NEMO (Rs = 0.311, P < .05), transcripts 1A (Rs = 0.463, P < .01), 1B (Rs = 0.454, P < .01), and 1C (Rs = 0.563, P < .001) in fetal blood was observed in preeclamptic pregnancies. In addition, the mRNA levels for total NEMO and transcripts 1A, 1B, and 1C were lower in placentas derived from pregnancies complicated by preeclampsia. CONCLUSION Simultaneous increase of NEMO gene expression in maternal and fetal blood seems to be relevant for preeclampsia development. The results of our study also suggest that a decreased NEMO gene expression level in preeclamptic placentas may be the main reason for their intensified apoptosis.
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Affiliation(s)
- Agata Sakowicz
- Department of Medical Biotechnology, Medical University of Lodz, Poland.
| | - Paulina Hejduk
- Department of Medical Biotechnology, Medical University of Lodz, Poland
| | - Tadeusz Pietrucha
- Department of Medical Biotechnology, Medical University of Lodz, Poland
| | | | | | - Karolina Pospiech
- Department of Molecular Cancerogenesis, Medical University of Lodz, Poland
| | - Agnieszka Gach
- Department of Genetic, Polish Mother's Memorial Hospital-Research Institute in Lodz, Poland
| | | | - Bartosz Sakowicz
- Department of Microelectronics and Computer Science, Lodz University of Technology, Poland
| | - Marek Kaminski
- Department of Microelectronics and Computer Science, Lodz University of Technology, Poland
| | - Grzegorz Krasomski
- Department of Obstetrics and Gynecology, Polish Mother's Memorial Hospital-Research Institute in Lodz, Poland
| | - Lidia Biesiada
- Department of Obstetrics and Gynecology, Polish Mother's Memorial Hospital-Research Institute in Lodz, Poland
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Kaypee S, Sudarshan D, Shanmugam MK, Mukherjee D, Sethi G, Kundu TK. Aberrant lysine acetylation in tumorigenesis: Implications in the development of therapeutics. Pharmacol Ther 2016; 162:98-119. [PMID: 26808162 DOI: 10.1016/j.pharmthera.2016.01.011] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The 'language' of covalent histone modifications translates environmental and cellular cues into gene expression. This vast array of post-translational modifications on histones are more than just covalent moieties added onto a protein, as they also form a platform on which crucial cellular signals are relayed. The reversible lysine acetylation has emerged as an important post-translational modification of both histone and non-histone proteins, dictating numerous epigenetic programs within a cell. Thus, understanding the complex biology of lysine acetylation and its regulators is essential for the development of epigenetic therapeutics. In this review, we will attempt to address the complexities of lysine acetylation in the context of tumorigenesis, their role in cancer progression and emphasize on the modalities developed to target lysine acetyltransferases towards cancer treatment.
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Affiliation(s)
- Stephanie Kaypee
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, Karnataka, India
| | - Deepthi Sudarshan
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, Karnataka, India
| | - Muthu K Shanmugam
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, 117600, Singapore
| | - Debanjan Mukherjee
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, Karnataka, India
| | - Gautam Sethi
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, 117600, Singapore
| | - Tapas K Kundu
- Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, Karnataka, India.
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Esposito E, Napolitano G, Pescatore A, Calculli G, Incoronato MR, Leonardi A, Ursini MV. COMMD7 as a novel NEMO interacting protein involved in the termination of NF-κB signaling. J Cell Physiol 2016; 231:152-61. [PMID: 26060140 DOI: 10.1002/jcp.25066] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 06/05/2015] [Indexed: 11/08/2022]
Abstract
NEMO/IKKγ is the regulatory subunit of the IκB Kinase (IKK) complex, required for the activation of the NF-κB pathway, which is involved in a variety of key processes, including immunity, inflammation, differentiation, and cell survival. Termination of NF-κB activity on specific -κB responsive genes, which is crucial for the resolution of inflammatory responses, can be achieved by direct degradation of the chromatin-bound NF-κB subunit RelA/p65, a process mediated by a protein complex that contains Copper Metabolism Murr1 Domain 1 (COMMD1). In this study, we identify COMMD7, another member of the COMMDs protein family, as a novel NEMO-interacting protein. We show that COMMD7 exerts an inhibitory effect on NF-κB activation upon TNFα stimulation. COMMD7 interacts with COMMD1 and together they cooperate to down-regulate NF-κB activity. Accordingly, termination of TNFα-induced NF-κB activity on the -κB responsive gene, Icam1, is defective in cells silenced for COMMD7 expression. Furthermore, this impairment is not greatly increased when we silence the expression of both COMMD7 and COMMD1 indicating that the two proteins participate in the same pathway of termination of TNFα-induced NF-κB activity. Importantly, we have demonstrated that COMMD7's binding to NEMO does not interfere with the binding to the IKKs, and that the disruption of the IKK complex through the use of the NBP competitor impairs the termination of NF-κB activity. We propose that an intact IKK complex is required for the termination of NF-κB-dependent transcription and that COMMD7 acts as a scaffold in the IKK-mediated NF-κB termination.
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Affiliation(s)
- Elio Esposito
- Institute of Genetics and Biophysics, 'Adriano Buzzati-Traverso' (CNR), Naples, Italy
| | - Gennaro Napolitano
- Institute of Genetics and Biophysics, 'Adriano Buzzati-Traverso' (CNR), Naples, Italy
| | - Alessandra Pescatore
- Institute of Genetics and Biophysics, 'Adriano Buzzati-Traverso' (CNR), Naples, Italy
| | - Giuseppe Calculli
- Institute of Genetics and Biophysics, 'Adriano Buzzati-Traverso' (CNR), Naples, Italy
| | | | - Antonio Leonardi
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, "Federico II" University of Naples, via S. Pansini 5, Naples, Italy
| | - Matilde Valeria Ursini
- Institute of Genetics and Biophysics, 'Adriano Buzzati-Traverso' (CNR), Naples, Italy.,IRCCS SDN, Via E. Gianturco 113, Naples, Italy
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10
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Thakar NY, Ovchinnikov DA, Hastie ML, Kobe B, Gorman JJ, Wolvetang EJ. TRAF2 recruitment via T61 in CD30 drives NFκB activation and enhances hESC survival and proliferation. Mol Biol Cell 2015; 26:993-1006. [PMID: 25568342 PMCID: PMC4342033 DOI: 10.1091/mbc.e14-08-1290] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
CD30 activates NFκB signaling in human embryonic stem cells. A single threonine residue in the CD30v protein is critical for this and recruitment of TRAF2. The data reveal the importance of this interaction for hESC survival and proliferation. CD30 (TNFRSF8), a tumor necrosis factor receptor family protein, and CD30 variant (CD30v), a ligand-independent form encoding only the cytoplasmic signaling domain, are concurrently overexpressed in transformed human embryonic stem cells (hESCs) or hESCs cultured in the presence of ascorbate. CD30 and CD30v are believed to increase hESC survival and proliferation through NFκB activation, but how this occurs is largely unknown. Here we demonstrate that hESCs that endogenously express CD30v and hESCs that artificially overexpress CD30v exhibit increased ERK phosphorylation levels, activation of the canonical NFκB pathway, down-regulation of the noncanonical NFκB pathway, and reduced expression of the full-length CD30 protein. We further find that CD30v, surprisingly, resides predominantly in the nucleus of hESC. We demonstrate that alanine substitution of a single threonine residue at position 61 (T61) in CD30v abrogates CD30v-mediated NFκB activation, CD30v-mediated resistance to apoptosis, and CD30v-enhanced proliferation, as well as restores normal G2/M-checkpoint arrest upon H2O2 treatment while maintaining its unexpected subcellular distribution. Using an affinity purification strategy and LC-MS, we identified TRAF2 as the predominant protein that interacts with WT CD30v but not the T61A-mutant form in hESCs. The identification of Thr-61 as a critical residue for TRAF2 recruitment and canonical NFκB signaling by CD30v reveals the substantial contribution that this molecule makes to overall NFκB activity, cell cycle changes, and survival in hESCs.
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Affiliation(s)
- Nilay Y Thakar
- Stem Cell Engineering Group, Australian Institute for Bioengineering and Nanotechnology, University of Queensland, St. Lucia, QLD 4072, Australia
| | - Dmitry A Ovchinnikov
- Stem Cell Engineering Group, Australian Institute for Bioengineering and Nanotechnology, University of Queensland, St. Lucia, QLD 4072, Australia
| | - Marcus L Hastie
- Protein Discovery Centre, QIMR Berghofer Medical Research Institute, Herston, QLD 4029, Australia
| | - Bostjan Kobe
- School of Chemistry and Molecular Biosciences, Australian Infectious Diseases Research Centre and Institute for Molecular Bioscience, University of Queensland, St. Lucia, 4067 QLD, Australia
| | - Jeffrey J Gorman
- Protein Discovery Centre, QIMR Berghofer Medical Research Institute, Herston, QLD 4029, Australia
| | - Ernst J Wolvetang
- Stem Cell Engineering Group, Australian Institute for Bioengineering and Nanotechnology, University of Queensland, St. Lucia, QLD 4072, Australia
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11
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Gamboni F, Escobar GA, Moore EE, Dzieciatkowska M, Hansen KC, Mitra S, Nydam TA, Silliman CC, Banerjee A. Clathrin complexes with the inhibitor kappa B kinase signalosome: imaging the interactome. Physiol Rep 2014; 2:2/7/e12035. [PMID: 24994893 PMCID: PMC4187570 DOI: 10.14814/phy2.12035] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Many receptors involved with innate immunity activate the inhibitor kappa B kinase signalosome
(IKK). The active complex appears to be assembled from the two kinase units,
IKKα and IKKβ with the regulatory protein NEMO.
Because we previously found that RNA silencing of clathrin heavy chains (CHC), in transformed human
lung pneumocytes (A549), decreased TNFα‐induced signaling and
phosphorylation of inhibitor kappa B (IκB), we hypothesized that CHC forms
cytoplasmic complexes with members of the IKK signalosome. Widely available antibodies were used to
immunoprecipitate IKKα and NEMO interactomes. Analysis of the affinity
interactomes by mass spectrometry detected clathrin with both baits with high confidence. Using the
same antibodies for indirect digital immunofluorescence microscopy and FRET, the CHC–IKK
complexes were visualized together with NEMO or HSP90. The natural variability of protein amounts in
unsynchronized A549 cells was used to obtain statistical correlation for several complexes, at
natural levels and without invasive labeling. Analyses of voxel numbers indicated that: (i)
CHC–IKK complexes are not part of the IKK signalosome itself but, likely, precursors of
IKK–NEMO complexes. (ii) CHC–IKKβ complexes may arise from
IKKβ–HSP90 complexes. Clathrin forms complexes with IKKa, IKKb, and NEMO, but apparently not the canonical signalosome.
These complexes are identified, for the first time, by affinity proteomics and triple FRET without
altering molecular structure.
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Affiliation(s)
- Fabia Gamboni
- Department of Surgery, University of Colorado Denver, Aurora, Colorado
| | - Guillermo A Escobar
- Department of Surgery, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Ernest E Moore
- Department of Surgery, University of Colorado Denver, Aurora, Colorado Department of Surgery, Denver Health Medical Center, Denver, Colorado
| | | | - Kirk C Hansen
- Department of Biochemistry and Molecular Genetics, UC Denver Mass Spectrometry and Proteomics Facility, Aurora, Colorado
| | - Sanchayita Mitra
- Department of Surgery, University of Colorado Denver, Aurora, Colorado
| | - Trevor A Nydam
- Department of Surgery, University of Colorado Denver, Aurora, Colorado
| | - Christopher C Silliman
- Department of Surgery, University of Colorado Denver, Aurora, Colorado Belle Bonfils Blood Center, Denver, Colorado
| | - Anirban Banerjee
- Department of Surgery, University of Colorado Denver, Aurora, Colorado
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Tien DN, Kishihata M, Yoshikawa A, Hashimoto A, Sabe H, Nishi E, Kamei K, Arai H, Kita T, Kimura T, Yokode M, Ashida N. AMAP1 as a negative-feedback regulator of nuclear factor-κB under inflammatory conditions. Sci Rep 2014; 4:5094. [PMID: 24865276 PMCID: PMC4035583 DOI: 10.1038/srep05094] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Accepted: 05/07/2014] [Indexed: 12/24/2022] Open
Abstract
NF-κB is a major transcriptional factor regulating many cellular functions including inflammation; therefore, its appropriate control is of high importance. The detailed mechanism of its activation has been well characterized, but that of negative regulation is poorly understood. In this study, we showed AMAP1, an Arf-GTPase activating protein, as a negative feedback regulator for NF-κB by binding with IKKβ, an essential kinase in NF-κB signaling. Proteomics analysis identified AMAP1 as a binding protein with IKKβ. Overexpression of AMAP1 suppressed NF-κB activity by interfering the binding of IKKβ and NEMO, and deletion of AMAP1 augmented NF-κB activity. The activation of NF-κB induced translocation of AMAP1 to cytoplasm from cell membrane and nucleus, which resulted in augmented interaction of AMAP1 and IKKβ. These results demonstrated a novel role of AMAP1 as a negative feedback regulator of NF-κB, and presented it as a possible target for anti-inflammatory treatments.
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Affiliation(s)
- Dat Nguyen Tien
- 1] Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan [2] Department of Clinical Innovative Medicine, Institute for Advancement of Clinical and Translational Science, Kyoto University Hospital, Kyoto, Japan [3] Department of Biomolecular Engineering, Kyoto Institute of Technology, Kyoto, Japan
| | - Masako Kishihata
- 1] Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan [2] Department of Clinical Innovative Medicine, Institute for Advancement of Clinical and Translational Science, Kyoto University Hospital, Kyoto, Japan
| | - Ayumu Yoshikawa
- Department of Molecular Biology, Graduate School of Medicine, Hokkaido University, Hokkaido, Japan
| | - Ari Hashimoto
- Department of Molecular Biology, Graduate School of Medicine, Hokkaido University, Hokkaido, Japan
| | - Hisataka Sabe
- Department of Molecular Biology, Graduate School of Medicine, Hokkaido University, Hokkaido, Japan
| | - Eiichiro Nishi
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Kaeko Kamei
- Department of Biomolecular Engineering, Kyoto Institute of Technology, Kyoto, Japan
| | - Hidenori Arai
- Department of Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Toru Kita
- Kobe City Medical Center General Hospital, Kobe, Japan
| | - Takeshi Kimura
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Masayuki Yokode
- Department of Clinical Innovative Medicine, Institute for Advancement of Clinical and Translational Science, Kyoto University Hospital, Kyoto, Japan
| | - Noboru Ashida
- 1] Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan [2] Department of Clinical Innovative Medicine, Institute for Advancement of Clinical and Translational Science, Kyoto University Hospital, Kyoto, Japan
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13
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AZIZ MONOWAR, ISHIHARA SHUNJI, ANSARY MESBAHUDDIN, SONOYAMA HIROKI, TADA YASUMASA, OKA AKIHIKO, KUSUNOKI RYUSAKU, TAMAGAWA YUJI, FUKUBA NOBUHIKO, MISHIMA YOSHIYUKI, MISHIRO TSUYOSHI, OSHIMA NAOKI, MORIYAMA ICHIRO, ISHIMURA NORIHISA, SATO SHUICHI, YUKI TAKAFUMI, KAWASHIMA KOUSAKU, KINOSHITA YOSHIKAZU. Crosstalk between TLR5 and Notch1 signaling in epithelial cells during intestinal inflammation. Int J Mol Med 2013; 32:1051-62. [PMID: 24048326 DOI: 10.3892/ijmm.2013.1501] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 08/27/2013] [Indexed: 11/06/2022] Open
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14
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Huang WC, Hung MC. Beyond NF-κB activation: nuclear functions of IκB kinase α. J Biomed Sci 2013; 20:3. [PMID: 23343355 PMCID: PMC3563485 DOI: 10.1186/1423-0127-20-3] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 01/11/2013] [Indexed: 12/15/2022] Open
Abstract
IκB kinase (IKK) complex, the master kinase for NF-κB activation, contains two kinase subunits, IKKα and IKKβ. In addition to mediating NF-κB signaling by phosphorylating IκB proteins during inflammatory and immune responses, the activation of the IKK complex also responds to various stimuli to regulate diverse functions independently of NF-κB. Although these two kinases share structural and biochemical similarities, different sub-cellular localization and phosphorylation targets between IKKα and IKKβ account for their distinct physiological and pathological roles. While IKKβ is predominantly cytoplasmic, IKKα has been found to shuttle between the cytoplasm and the nucleus. The nuclear-specific roles of IKKα have brought increasing complexity to its biological function. This review highlights major advances in the studies of the nuclear functions of IKKα and the mechanisms of IKKα nuclear translocation. Understanding the nuclear activity is essential for targeting IKKα for therapeutics.
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Affiliation(s)
- Wei-Chien Huang
- Center for Molecular Medicine, China Medical University Hospital, Taichung, 40447, Taiwan.
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15
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Zhang M, Hu B, Li T, Peng Y, Guan J, Lai S, Zheng X. A CRM1-dependent nuclear export signal controls nucleocytoplasmic translocation of HSCARG, which regulates NF-κB activity. Traffic 2012; 13:790-9. [PMID: 22348310 DOI: 10.1111/j.1600-0854.2012.01346.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 02/17/2012] [Accepted: 02/20/2012] [Indexed: 12/22/2022]
Abstract
HSCARG is a newly identified nuclear factor-κB (NF-κB) inhibitor that plays important roles in cell growth. Our previous study found that HSCARG could shuttle between the nucleus and cytoplasm by sensing the change in cellular redox states. To further investigate the mechanism of HSCARG translocation and its effect on the regulation of NF-κB activity, we identified a previously uncharacterized nuclear export signal (NES) at residues 272-278 of HSCARG that is required for its cytoplasmic translocation. This leucine-rich NES was found to be mediated by chromosome region maintenance 1. More importantly, accumulation of HSCARG in the nucleus occurred following a mutation in the NES or oxidative stress, which attenuated the inhibition of NF-κB by HSCARG. These results indicate that nucleocytoplasmic translocation of HSCARG plays an important role in fine-tuning NF-κB signaling.
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Affiliation(s)
- Mei Zhang
- State Key Lab of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
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16
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Abstract
Human T-cell lymphotropic virus type 1 (HTLV-1) is the etiological agent of adult T-cell leukemia/lymphoma (ATL), whereas the highly related HTLV-2 is not associated with ATL or other cancers. In addition to ATL leukemogenesis, studies of the HTLV viruses also provide an exceptional model for understanding basic pathogenic mechanisms of virus-host interactions and human oncogenesis. Accumulating evidence suggests that the viral regulatory protein Tax and host inflammatory transcription factor NF-κB are largely responsible for the different pathogenic potentials of HTLV-1 and HTLV-2. Here, we discuss the molecular mechanisms of HTLV-1 oncogenic pathogenesis with a focus on the interplay between the Tax oncoprotein and NF-κB pro-oncogenic signaling. We also outline some of the most intriguing and outstanding questions in the fields of HTLV and NF-κB. Answers to those questions will greatly advance our understanding of ATL leukemogenesis and other NF-κB-associated tumorigenesis and will help us design personalized cancer therapies.
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17
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Temmerman ST, Ma CA, Zhao Y, Keenan J, Aksentijevich I, Fessler M, Brown MR, Knutsen A, Shapiro R, Jain A. Defective nuclear IKKα function in patients with ectodermal dysplasia with immune deficiency. J Clin Invest 2011; 122:315-26. [PMID: 22156202 DOI: 10.1172/jci42534] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Accepted: 09/21/2011] [Indexed: 11/17/2022] Open
Abstract
Ectodermal dysplasia with immune deficiency (EDI) is an immunological and developmental disorder caused by alterations in the gene encoding NF-κB essential modulator (NEMO; also known as IκB kinase γ subunit [IKKγ]). Missense mutations in the gene encoding NEMO are associated with reduced signal-induced nuclear translocation of NF-κB proteins, resulting in defective expression of NF-κB target genes. Here, we report 2 unrelated male patients with EDI, both of whom have normal NEMO coding sequences, but exhibit a marked reduction in expression of full-length NEMO protein. TLR4 stimulation of APCs from these patients induced normal cytoplasmic activation and nuclear translocation of NF-κB. However, cells deficient in full-length NEMO were defective in expression of NF-κB-regulated cytokines, such as IL-12, suggesting a downstream defect in chromatin accessibility for NF-κB transcription factors. TLR4-stimulated APCs from the patients were defective in IKKα-dependent H3 histone phosphorylation at the IL-12 promoter and recruitment of NF-κB heterodimers RelA and cRel to the promoter. Expression of a super-active form of IKKα restored IL-12 production in a NEMO knockdown human monocytic cell line following LPS treatment. Our findings suggest that NEMO regulates the nuclear function of IKKα and offer new insights into the mechanisms underlying diminished NF-κB signaling in patients with EDI.
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Affiliation(s)
- Stephane T Temmerman
- Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland 20892, USA
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18
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Importance of PIKKs in NF-κB activation by genotoxic stress. Biochem Pharmacol 2011; 82:1371-83. [PMID: 21872579 DOI: 10.1016/j.bcp.2011.07.105] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Revised: 07/26/2011] [Accepted: 07/29/2011] [Indexed: 01/11/2023]
Abstract
Alteration of the genome integrity leads to the activation of a vast network of cellular responses named "DNA damage response". Three kinases from the phosphoinositide 3-kinase-like protein kinase family regulate this network; ATM and DNA-PK both activated by DNA double-strand breaks and ATR activated by replication blocks. "DNA damage response" pathway coordinates cell cycle arrest, DNA repair, and the activation of transcription factors such as p53 and NF-κB. It controls senescence/apoptosis/survival of the damaged cells. Cell death or survival result from a tightly regulated balance between antagonist pro- and anti-apoptotic signals. NF-κB is a key transcription factor involved in immunity, inflammation and cell transformation. When activated by DNA double-strand breaks, NF-κB has most often a pro-survival effect and thereof interferes with chemotherapy treatments that often rely on DNA damage to induce tumor cell death (i.e. topoisomerase inhibitors and ionizing radiation). NF-κB is thus an important pharmaceutical target. Agents leading to replication stress induce a pro-apoptotic NF-κB. The molecular mechanisms initiated by DNA lesions leading to NF-κB nuclear translocation have been extensively studied these last years. In this review, we will focus on ATM, ATR and DNA-PK functions both in the IKKα/IKKβ/NEMO-dependent or -independent signaling pathways and on the regulation they can exercise at the promoter level of NF-κB regulated genes.
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19
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Kwak YT, Radaideh SM, Ding L, Li R, Frenkel E, Story MD, Girard L, Minna J, Verma UN. Cells lacking IKKα show nuclear cyclin D1 overexpression and a neoplastic phenotype: role of IKKα as a tumor suppressor. Mol Cancer Res 2011; 9:341-9. [PMID: 21317297 DOI: 10.1158/1541-7786.mcr-10-0248] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The catalytic subunits of IκB kinase (IKK) complex, IKKα and IKKβ, are involved in activation of NF-κB and in mediating a variety of other biological functions. Though these proteins have a high-sequence homology, IKKα exhibits different functional characteristics as compared with IKKβ. Earlier, we have shown that cyclin D1 is overexpressed and predominantly localized in the nucleus of IKKα(-/-) cells, indicating that IKKα regulates turnover and subcellular distribution of cyclin D1, which is mediated by IKKα-induced phosphorylation of cyclin D1. Because cyclin D nuclear localization is implicated in tumor development, we examined whether the absence of IKKα leads to tumor development as well. In the current study, we show that IKKα plays a critical role in tumorigenesis. Though IKKα(-/-) MEF cells show a slower anchorage-dependent growth, they are clonogenic in soft agar. These cells are tumorigenic in nude mice. Microarray analysis of IKKα(-/-) cells indicates a differential expression of genes involved in proliferation and apoptosis. Furthermore, analysis of microarray data of human lung cancer cell lines revealed decreased IKKα RNA expression level as compared with cell lines derived from normal bronchial epithelium. These results suggest that IKKα may function as a tumor suppressor gene. Absence of IKKα may induce tumorigenicity by nuclear localization of cyclin D1 and modulating the expression of genes involved in neoplastic transformation.
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Affiliation(s)
- Youn-Tae Kwak
- Department of Medicine, Division of Hematology/Oncology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA
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20
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Abstract
The accumulation of protein aggregates in neurons appears to be a basic feature of neurodegenerative disease. In Huntington's Disease (HD), a progressive and ultimately fatal neurodegenerative disorder caused by an expansion of the polyglutamine repeat within the protein Huntingtin (Htt), the immediate proximal cause of disease is well understood. However, the cellular mechanisms which modulate the rate at which fragments of Htt containing polyglutamine accumulate in neurons is a central issue in the development of approaches to modulate the rate and extent of neuronal loss in this disease. We have recently found that Htt is phosphorylated by the kinase IKK on serine (S) 13, activating its phosphorylation on S16 and its acetylation and poly-SUMOylation, modifications that modulate its clearance by the proteasome and lysosome in cells. In the discussion here I suggest that Htt may have a normal function in the lysosomal mechanism of selective macroautophagy involved in its own degradation which may share some similarity with the yeast cytoplasm to vacuole targeting (Cvt) pathway. Pharmacologic activation of this pathway may be useful early in disease progression to treat HD and other neurodegenerative diseases characterized by the accumulation of disease proteins.
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Affiliation(s)
- Joan S Steffan
- Department of Psychiatry and Human Behavior, University of California, Irvine, CA, USA.
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21
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NEMO stabilizes c-Myc through direct interaction in the nucleus. FEBS Lett 2010; 584:4524-30. [DOI: 10.1016/j.febslet.2010.10.031] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Revised: 10/06/2010] [Accepted: 10/08/2010] [Indexed: 11/19/2022]
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22
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von Kampen O, Lipinski S, Till A, Martin SJ, Nietfeld W, Lehrach H, Schreiber S, Rosenstiel P. Caspase recruitment domain-containing protein 8 (CARD8) negatively regulates NOD2-mediated signaling. J Biol Chem 2010; 285:19921-6. [PMID: 20385562 PMCID: PMC2888403 DOI: 10.1074/jbc.m110.127480] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2010] [Indexed: 01/07/2023] Open
Abstract
Caspase activating and recruitment domain 8 (CARD8) has been implicated as a co-regulator of several pro-inflammatory and apoptotic signaling pathways. In the present study, we demonstrate a specific modulation of NOD2-induced signaling by CARD8 in intestinal epithelial cells. We show that CARD8 physically interacts with NOD2 and inhibits nodosome assembly and subsequent signaling upon muramyl-dipeptide stimulation. Furthermore, CARD8 inhibits the direct bactericidal effect of NOD2 against intracellular infection by Listeria monocytogenes. Thus, CARD8 represents a novel molecular switch involved in the endogenous regulation of NOD2-dependent inflammatory processes in epithelial cells.
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Affiliation(s)
- Oliver von Kampen
- From the Institute of Clinical Molecular Biology, Christian Albrechts University, Kiel D-24105, Germany
| | - Simone Lipinski
- From the Institute of Clinical Molecular Biology, Christian Albrechts University, Kiel D-24105, Germany
| | - Andreas Till
- From the Institute of Clinical Molecular Biology, Christian Albrechts University, Kiel D-24105, Germany
| | - Seamus J. Martin
- the Molecular Cell Biology Laboratory, Department of Genetics, The Smurfit Institute, Trinity College, Dublin 2, Ireland, and
| | - Wilfried Nietfeld
- the Max Planck Institute for Molecular Genetics, Berlin D-14195, Germany
| | - Hans Lehrach
- the Max Planck Institute for Molecular Genetics, Berlin D-14195, Germany
| | - Stefan Schreiber
- From the Institute of Clinical Molecular Biology, Christian Albrechts University, Kiel D-24105, Germany
| | - Philip Rosenstiel
- From the Institute of Clinical Molecular Biology, Christian Albrechts University, Kiel D-24105, Germany
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23
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Abstract
NF-kappaB (nuclear factor kappaB) is a heterodimeric transcription factor that is constitutively expressed in all cell types and has a central role as a transcriptional regulator in response to cellular stress. In the present review, we discuss the role of NF-kappaB signalling in the maintenance of liver homoeostasis as well as in the pathogenesis of a wide variety of conditions affecting the liver, including viral hepatitis, steatohepatitis, cirrhosis and hepatocellular carcinoma. Much of the current knowledge of NF-kappaB signalling in the liver relates to the canonical pathway, the IKK [IkappaB (inhibitor of kappaB) kinase] complex and the RelA subunit. We explore the weaknesses of the experimental approaches to date and suggest that further work is needed to investigate in detail the discreet functions of each of the Rel subunits in liver physiology and disease.
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25
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Thompson LM, Aiken CT, Kaltenbach LS, Agrawal N, Illes K, Khoshnan A, Martinez-Vincente M, Arrasate M, O'Rourke JG, Khashwji H, Lukacsovich T, Zhu YZ, Lau AL, Massey A, Hayden MR, Zeitlin SO, Finkbeiner S, Green KN, LaFerla FM, Bates G, Huang L, Patterson PH, Lo DC, Cuervo AM, Marsh JL, Steffan JS. IKK phosphorylates Huntingtin and targets it for degradation by the proteasome and lysosome. ACTA ACUST UNITED AC 2009; 187:1083-99. [PMID: 20026656 PMCID: PMC2806289 DOI: 10.1083/jcb.200909067] [Citation(s) in RCA: 275] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Expansion of the polyglutamine repeat within the protein Huntingtin (Htt) causes Huntington's disease, a neurodegenerative disease associated with aging and the accumulation of mutant Htt in diseased neurons. Understanding the mechanisms that influence Htt cellular degradation may target treatments designed to activate mutant Htt clearance pathways. We find that Htt is phosphorylated by the inflammatory kinase IKK, enhancing its normal clearance by the proteasome and lysosome. Phosphorylation of Htt regulates additional post-translational modifications, including Htt ubiquitination, SUMOylation, and acetylation, and increases Htt nuclear localization, cleavage, and clearance mediated by lysosomal-associated membrane protein 2A and Hsc70. We propose that IKK activates mutant Htt clearance until an age-related loss of proteasome/lysosome function promotes accumulation of toxic post-translationally modified mutant Htt. Thus, IKK activation may modulate mutant Htt neurotoxicity depending on the cell's ability to degrade the modified species.
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26
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Solt LA, Madge LA, May MJ. NEMO-binding domains of both IKKalpha and IKKbeta regulate IkappaB kinase complex assembly and classical NF-kappaB activation. J Biol Chem 2009; 284:27596-608. [PMID: 19666475 DOI: 10.1074/jbc.m109.047563] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Proinflammatory NF-kappaB activation requires the IkappaB (inhibitor of NF-kappaB) kinase (IKK) complex that contains two catalytic subunits named IKKalpha and IKKbeta and a regulatory subunit named NF-kappaB essential modulator (NEMO). NEMO and IKKbeta are essential for tumor necrosis factor (TNF)-induced NF-kappaB activation, and we recently demonstrated that NEMO and IKKalpha are sufficient for interleukin (IL)-1-induced signaling. IKKalpha and IKKbeta both contain a functional NEMO-binding domain (NBD); however, the role of NEMO association with each kinase in NF-kappaB signaling and IKK complex formation remains unclear. To address this question, we stably reconstituted IKKalpha(-/-) and IKKbeta(-/-) murine embryonic fibroblasts (MEFs) with wild-type (WT) or NBD-deficient (DeltaNBD) versions of IKKalpha and IKKbeta, respectively. TNF-induced classical NF-kappaB activation in IKKbeta(-/-) MEFs was rescued by IKKbeta(WT) but not IKKbeta(DeltaNBD), whereas neither IKKbeta(WT) nor IKKbeta(DeltaNBD) affected IL-1-induced NF-kappaB signaling. As previously described, classical NF-kappaB transcriptional activity was absent in IKKalpha(-/-) cells. Reconstitution with either IKKalpha(WT) or IKKalpha(DeltaNBD) rescued both IL-1 and TNF-induced transcription, demonstrating that NEMO association is not required for IKKalpha-dependent regulation of NF-kappaB-dependent transcription. Stably expressed IKKalpha(WT) or IKKbeta(WT) associated with endogenous IKKs and NEMO in IKKalpha(-/-) or IKKbeta(-/-) MEFs, respectively, resulting in formation of the heterotrimeric IKKalpha-IKKbeta-NEMO complex. In contrast, although the IKKalpha(DeltaNBD) and IKKbeta(DeltaNBD) mutants associated with endogenous IKKs containing an NBD, these dimeric endogenous IKK-IKK(DeltaNBD) complexes did not associate with NEMO. These findings therefore demonstrate that formation of the heterotrimeric IKKalpha-IKKbeta-NEMO holocomplex absolutely requires two intact NEMO-binding domains.
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Affiliation(s)
- Laura A Solt
- Department of Animal Biology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania 19104, USA
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27
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Abstract
Nuclear factor κB (NF-κB) is an inducible transcription factor that tightly regulates the expression of a large cohort of genes. As a key component of the cellular machinery NF-κB is involved in a wide range of biological processes including innate and adaptive immunity, inflammation, cellular stress responses, cell adhesion, apoptosis and proliferation. Appropriate regulation of NF-κB is critical for the proper function and survival of the cell. Aberrant NF-κB activity has now been implicated in the pathogenesis of several diseases ranging from inflammatory bowel disease to autoimmune conditions such as rheumatoid arthritis. Systems governing NF-κB activity are complex and there is an increased understanding of the importance of nuclear events in regulating NF-κB's activities as a transcription factor. A number of novel nuclear regulators of NF-κB such as IκB-ζ and PDZ and LIM domain 2 (PDLIM2) have now been identified, adding another layer to the mechanics of NF-κB regulation. Further insight into the functions of these molecules raises the prospect for better understanding and rational design of therapeutics for several important diseases.
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Affiliation(s)
- Arun K Mankan
- Department of Clinical Medicine and Institute of Molecular Medicine, Trinity College, Dublin, Ireland.
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28
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Singh A, Zarember KA, Kuhns DB, Gallin JI. Impaired priming and activation of the neutrophil NADPH oxidase in patients with IRAK4 or NEMO deficiency. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2009; 182:6410-7. [PMID: 19414794 PMCID: PMC3733113 DOI: 10.4049/jimmunol.0802512] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The NADPH oxidase (NOX), an oligomeric enzyme, plays a key role in polymorphonuclear neutrophil (PMN)-mediated host defense by producing cytotoxic superoxide anion (O(2)( )). Whereas in vitro and biochemical studies have examined the assembly and activation of this important host immune defense system, few studies have examined the function of NOX in human patients with primary immunodeficiency other than chronic granulomatous disease. We studied the activation of NOX in PMN from patients with two distinct immunodeficiencies, IL-1R-associated kinase (IRAK)4 deficiency and NF-kappaB essential modulator (NEMO or IkappaB kinase gamma) deficiency. We observed impaired O(2)( ) generation by LPS-treated and fMLP-activated IRAK4-deficient PMN that correlated with decreased phosphorylation of p47(phox) and subnormal translocation of p47(phox), p67(phox), Rac2, and gp91(phox)/Nox2 to the membranes indicating that TLR4 signaling to the NOX activation pathway requires IRAK4. NEMO-deficient PMN generated significantly less O(2)( ) in response to LPS-primed fMLP and translocated less p67(phox) than normal PMN, although p47(phox) and Rac2 translocation were normal. Generally, responses of NEMO-deficient cells were intermediate between IRAK4-deficient cells and normal cells. Decreased LPS- and fMLP-induced phosphorylation of p38 MAPK in both IRAK4- and NEMO-deficient PMN implicates additional signal transduction pathways in regulating PMN activation by LPS and fMLP. Decreased activation of NOX may contribute to the increased risk of infection seen in patients with IRAK4 and NEMO deficiency.
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Affiliation(s)
- Anjali Singh
- Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, NIH, 10 Center Drive, Room 10CRC/5-3816, MSC-1456, Bethesda, MD, 20892
| | - Kol A. Zarember
- Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, NIH, 10 Center Drive, Room 10CRC/5-3816, MSC-1456, Bethesda, MD, 20892
| | - Douglas B. Kuhns
- Clinical Services Program, SAIC-Frederick, Inc., NCI-Frederick, Frederick, MD 21702
| | - John I. Gallin
- Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, NIH, 10 Center Drive, Room 10CRC/5-3816, MSC-1456, Bethesda, MD, 20892
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Austin RL, Rune A, Bouzakri K, Zierath JR, Krook A. siRNA-mediated reduction of inhibitor of nuclear factor-kappaB kinase prevents tumor necrosis factor-alpha-induced insulin resistance in human skeletal muscle. Diabetes 2008; 57:2066-73. [PMID: 18443205 PMCID: PMC2494681 DOI: 10.2337/db07-0763] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
OBJECTIVE Proinflammatory cytokines contribute to systemic low-grade inflammation and insulin resistance. Tumor necrosis factor (TNF)-alpha impedes insulin signaling in insulin target tissues. We determined the role of inhibitor of nuclear factor-kappaB kinase (IKK)beta in TNF-alpha-induced impairments in insulin signaling and glucose metabolism in skeletal muscle. RESEARCH DESIGN AND METHODS Small interfering RNA (siRNA) was used to silence IKKbeta gene expression in primary human skeletal muscle myotubes from nondiabetic subjects. siRNA gene silencing reduced IKKbeta protein expression 73% (P < 0.05). Myotubes were incubated in the absence or presence of insulin and/or TNF-alpha, and effects of IKKbeta silencing on insulin signaling and glucose metabolism were determined. RESULTS Insulin increased glucose uptake 1.7-fold (P < 0.05) and glucose incorporation into glycogen 3.8-fold (P < 0.05) in myotubes from nondiabetic subjects. TNF-alpha exposure fully impaired insulin-mediated glucose uptake and metabolism. IKKbeta siRNA protected against TNF-alpha-induced impairments in glucose metabolism, since insulin-induced increases in glucose uptake (1.5-fold; P < 0.05) and glycogen synthesis (3.5-fold; P < 0.05) were restored. Conversely, TNF-alpha-induced increases in insulin receptor substrate-1 serine phosphorylation (Ser(312)), Jun NH(2)-terminal kinase phosphorylation, and extracellular signal-related kinase-1/2 mitogen-activated protein kinase (MAPK) phosphorylation were unaltered by siRNA-mediated IKKbeta reduction. siRNA-mediated IKKbeta reduction prevented TNF-alpha-induced insulin resistance on Akt Ser(473) and Thr(308) phosphorylation and phosphorylation of the 160-kDa Akt substrate AS160. IKKbeta silencing had no effect on cell differentiation. Finally, mRNA expression of GLUT1 or GLUT4 and protein expression of MAPK kinase kinase kinase isoform 4 (MAP4K4) was unaltered by IKKbeta siRNA. CONCLUSIONS IKKbeta silencing prevents TNF-alpha-induced impairments in insulin action on Akt phosphorylation and glucose uptake and metabolism in human skeletal muscle.
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Affiliation(s)
- Reginald L Austin
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
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30
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Calao M, Burny A, Quivy V, Dekoninck A, Van Lint C. A pervasive role of histone acetyltransferases and deacetylases in an NF-kappaB-signaling code. Trends Biochem Sci 2008; 33:339-49. [PMID: 18585916 DOI: 10.1016/j.tibs.2008.04.015] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2008] [Revised: 04/28/2008] [Accepted: 04/29/2008] [Indexed: 01/08/2023]
Abstract
Most nuclear factor-kappaB (NF-kappaB) inducers converge to activate the IkappaB kinase (IKK) complex, leading to NF-kappaB nuclear accumulation. However, depending on the inducer and the cell line, the subset of NF-kappaB-induced genes is different, underlining a complex regulation network. Recent findings have begun to delineate that histone and non-histone protein acetylation is involved, directly and indirectly, in controlling the duration, strength and specificity of the NF-kappaB-activating signaling pathway at multiple levels. Acetylation and deacetylation events, in combination with other post-translational protein modifications, generate an 'NF-kappaB-signaling code' and regulate NF-kappaB-dependent gene transcription in an inducer- and promoter-dependent manner. Indeed, the intricate involvement of histone acetyltransferases and histone deacetylases modulates both the NF-kappaB-signaling pathway and the transcriptional transactivation of NF-kappaB-dependent genes.
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Affiliation(s)
- Miriam Calao
- Laboratory of Molecular Virology, Institut de Biologie et de Médecine Moléculaires, Université Libre de Bruxelles, 12 Rue des Profs Jeener et Brachet, 6041 Gosselies, Belgium
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31
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A nuclear role for Kaposi's sarcoma-associated herpesvirus-encoded K13 protein in gene regulation. Oncogene 2008; 27:5243-53. [PMID: 18469854 DOI: 10.1038/onc.2008.150] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV)-encoded viral FLICE inhibitory protein K13 interacts with a cytosolic IkappaB kinase (IKK) complex to activate nuclear factor-kappaB (NF-kappaB). We recently reported that K13 antagonizes KSHV lytic regulator RTA (replication and transcription activator) and blocks lytic replication, but spares RTA-induced viral interleukin-6 (vIL6). Here we report that K13 is also present in the nuclear compartment, a property not shared by its structural homologs. K13 interacts with and activates the nuclear IKK complex, and binds to the IkappaBalpha promoter. K13 mutants that are retained in the cytosol lack NF-kappaB activity. However, neither the IKKs nor NF-kappaB activation is required for nuclear localization of K13. Instead, this ability is dependent on a nuclear localization signal located in its N-terminal 40 amino acids. Finally, K13, along with p65/RelA, binds to the promoters of a number of KSHV lytic genes, including RTA, ORF57 and vGPCR, but not to the promoter of the vIL6 gene. Thus, K13 has an unexpected nuclear role in viral and cellular gene regulation and its differential binding to the promoters of lytic genes may not only contribute to the inhibition of KSHV lytic replication, but may also account for the escape of vIL6 from K13-induced transcriptional suppression.
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32
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Boersma MC, Meffert MK. Novel roles for the NF-kappaB signaling pathway in regulating neuronal function. Sci Signal 2008; 1:pe7. [PMID: 18272467 DOI: 10.1126/stke.16pe7] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Two new reports offer exciting evidence of novel roles for components of the nuclear factor kappaB (NF-kappaB) pathway in the nervous system. Transcriptional activation by NF-kappaB and chromatin remodeling by inhibitor of kappaB (IkappaB) kinase complex (IKK) have been linked to recall and reconsolidation of conditioned fear memories in the mammalian central nervous system. In the Drosophila neuromuscular junction, a member of the NF-kappaB family has been reported to regulate glutamate receptor clustering. Both reports could have important implications for the function of the NF-kappaB signaling pathway in neuronal plasticity.
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Affiliation(s)
- Matt C Boersma
- Departments of Biological Chemistry and Neuroscience, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA
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33
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Abstract
Controlled nucleocytoplasmic localization regulates activity of NF kappa B as well as other transcription factors. Analysis of the nucleocytoplasmic protein shuttling has been greatly facilitated by the use of leptomycin B (LMB), an inhibitor of CRM1-dependent nuclear export. The authors have previously shown that LMB inhibits NF kappa B activity in human neutrophils by increasing the nuclear accumulation of NF kappa B inhibitor, I kappa B alpha. In this chapter, the authors describe a protocol that uses LMB to study the nucleocytoplasmic shuttling of I kappa B alpha in human macrophage-like U937 cells, thus inhibiting NF kappa B activity. This protocol should be readily adaptable to analyze the nucleocytoplasmic shuttling of other proteins in human leukocytes.
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34
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Yoshida K, Ozaki T, Furuya K, Nakanishi M, Kikuchi H, Yamamoto H, Ono S, Koda T, Omura K, Nakagawara A. ATM-dependent nuclear accumulation of IKK-α plays an important role in the regulation of p73-mediated apoptosis in response to cisplatin. Oncogene 2007; 27:1183-8. [PMID: 17700524 DOI: 10.1038/sj.onc.1210722] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
I kappa B kinase (IKK) complex plays an important role in the regulation of signaling pathway that activates nuclear factor-kappa-B (NF-kappaB). Recently, we reported that cisplatin (CDDP) treatment causes a remarkable nuclear accumulation of IKK-alpha in association with stabilization and activation of p73. However, underlying mechanisms of CDDP-induced nuclear accumulation of IKK-alpha are elusive. Here, we found that ataxia-telangiectasia mutated (ATM) is one of upstream mediators of IKK-alpha during CDDP-induced apoptosis. In response to CDDP, ATM was phosphorylated at Ser-1981, which was accompanied with nuclear accumulation of IKK-alpha in HepG2 cells, whereas CDDP treatment had undetectable effects on IKK-alpha in ATM-deficient cells. Indirect immunofluorescence experiments demonstrated that phosphorylated form of ATM colocalizes with nuclear IKK-alpha in response to CDDP. In vitro kinase assay indicated that ATM phosphorylates IKK-alpha at Ser-473. Moreover, IKK-alpha-deficient MEFs displayed CDDP-resistant phenotype as compared with wild-type MEFs. Taken together, our present results suggest that ATM-mediated phosphorylation of nuclear IKK-alpha, which stabilizes p73, is one of the main apoptotic pathways in response to CDDP.
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Affiliation(s)
- K Yoshida
- Division of Biochemistry, Chiba Cancer Center Research Institute, Chiba, Japan
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35
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Ueda Y, Su Y, Richmond A. CCAAT displacement protein regulates nuclear factor-kappa beta-mediated chemokine transcription in melanoma cells. Melanoma Res 2007; 17:91-103. [PMID: 17496784 PMCID: PMC2665270 DOI: 10.1097/cmr.0b013e3280a60888] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Members of the nuclear factor-kappa beta (NF-kappaB) family maintain cellular homeostasis by enhancing the transcription of genes involved in inflammation, immune response, cell proliferation, and apoptosis. Melanoma tumor cells often express inflammatory mediators through enhanced activation of NF-kappaB. The NF-kappaB activation appears to result from the enhancer formation including NF-kappaB and lysine acetyl transferases such as p300, CREB (cyclic AMP-responsive element binding protein)-binding protein (CBP), and/or p300/CBP associating factor (PCAF). We observed that proteins expressed by Hs294T metastatic melanoma cells are highly acetylated compared with normal melanocytes, and dominant-negative PCAF reduced the basal and tumor necrosis factor-alpha-stimulated transcriptional activity of NF-kappaB. The promoter activity of NF-kappaB-regulated chemokines was also reduced by the expression of dominant-negative PCAF. The promoters of these chemokines contain a CCAAT displacement protein (CDP)-binding site near the NF-kappaB element. compared with vector-transduced cells, in CDP-transduced Hs294T cells: (i) over-expressed CDP bound efficiently to PCAF, (ii) tumor necrosis factor-alpha-stimulated chemokine expression and NF-kappaB-mediated transcription were reduced, and (iii) the binding of CBP to Rel A was reduced. These data suggest that CDP inhibits cytokine-induced NF-kappaB-regulated chemokine transcription. This study contributes to our understanding of the role of CDP in an enhanceosome of NF-kappaB-mediated chemokine transcription in human melanoma cells.
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Affiliation(s)
- Yukiko Ueda
- Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Yingjun Su
- Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Ann Richmond
- Department of Veterans Affairs, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
- Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
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36
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Zhou HJ, Pham LV, Tamayo AT, Lin-Lee YC, Fu L, Yoshimura LC, Ford RJ. Nuclear CD40 interacts with c-Rel and enhances proliferation in aggressive B-cell lymphoma. Blood 2007; 110:2121-7. [PMID: 17567982 PMCID: PMC1976364 DOI: 10.1182/blood-2007-02-073080] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
CD40 is an integral plasma membrane-associated member of the TNF receptor family that has recently been shown to also reside in the nucleus of both normal B cells and large B-cell lymphoma (LBCL) cells. However, the physiological function of CD40 in the B-cell nucleus has not been examined. In this study, we demonstrate that nuclear CD40 interacts with the NF-kappaB protein c-Rel, but not p65, in LBCL cells. Nuclear CD40 forms complexes with c-Rel on the promoters of NF-kappaB target genes, CD154, BLyS/BAFF, and Bfl-1/A1, in various LBCL cell lines. Wild-type CD40, but not NLS-mutated CD40, further enhances c-Rel-mediated Blys promoter activation as well as proliferation in LBCL cells. Studies in normal B cells and LBCL patient cells further support a nuclear transcriptional function for CD40 and c-Rel. Cooperation between nuclear CD40 and c-Rel appears to be important in regulating cell growth and survival genes involved in lymphoma cell proliferation and survival mechanisms. Modulating the nuclear function of CD40 and c-Rel could reveal new mechanisms in LBCL pathophysiology and provide potential new targets for lymphoma therapy.
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MESH Headings
- B-Cell Activating Factor/genetics
- B-Cell Activating Factor/metabolism
- B-Lymphocytes/metabolism
- CD40 Antigens/genetics
- CD40 Antigens/metabolism
- Cell Nucleus/metabolism
- Cell Proliferation
- Chromatin Immunoprecipitation
- Electrophoretic Mobility Shift Assay
- Genes, rel/physiology
- Humans
- Immunoprecipitation
- Luciferases/metabolism
- Lymphoma, B-Cell/genetics
- Lymphoma, B-Cell/metabolism
- Lymphoma, B-Cell/pathology
- Lymphoma, Large B-Cell, Diffuse/genetics
- Lymphoma, Large B-Cell, Diffuse/metabolism
- Lymphoma, Large B-Cell, Diffuse/pathology
- Promoter Regions, Genetic
- Thymidine/metabolism
- Transfection
- beta-Galactosidase/metabolism
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Affiliation(s)
- Hai-Jun Zhou
- Department of Hematopathology, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA
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37
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Furuya K, Ozaki T, Hanamoto T, Hosoda M, Hayashi S, Barker PA, Takano K, Matsumoto M, Nakagawara A. Stabilization of p73 by nuclear IkappaB kinase-alpha mediates cisplatin-induced apoptosis. J Biol Chem 2007; 282:18365-18378. [PMID: 17452332 DOI: 10.1074/jbc.m610522200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In response to DNA damage, p53 and its homolog p73 have a function antagonistic to NF-kappaB in deciding cell fate. Here, we show for the first time that p73, but not p53, is stabilized by physical interaction with nuclear IkappaB kinase (IKK)-alpha to enhance cisplatin (CDDP)-induced apoptosis. CDDP caused a significant increase in the amounts of nuclear IKK-alpha and p73alpha in human osteosarcoma-derived U2OS cells. Ectopic expression of IKK-alpha prolonged the half-life of p73 by inhibiting its ubiquitination and thereby enhancing its transactivation and pro-apoptotic activities. Consistent with these results, small interfering RNA-mediated knockdown of endogenous IKK-alpha inhibited the CDDP-mediated accumulation of p73alpha. The kinase-deficient mutant form of IKK-alpha interacted with p73alpha, but failed to stabilize it. Furthermore, CDDP-mediated accumulation of endogenous p73alpha was not detected in mouse embryonic fibroblasts (MEFs) prepared from IKK-alpha-deficient mice, and CDDP sensitivity was significantly decreased in IKK-alpha-deficient MEFs compared with wild-type MEFs. Thus, our results strongly suggest that the nuclear IKK-alpha-mediated accumulation of p73alpha is one of the novel molecular mechanisms to induce apoptotic cell death in response to CDDP, which may be particularly important in killing tumor cells with p53 mutation.
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Affiliation(s)
- Kazushige Furuya
- Division of Biochemistry, Chiba Cancer Center Research Institute, Chiba 260-8717, Japan; Second Department of Surgery, Yamanashi University School of Medicine, Yamanashi 409-3898, Japan
| | - Toshinori Ozaki
- Division of Biochemistry, Chiba Cancer Center Research Institute, Chiba 260-8717, Japan
| | - Takayuki Hanamoto
- Division of Biochemistry, Chiba Cancer Center Research Institute, Chiba 260-8717, Japan
| | - Mitsuchika Hosoda
- Division of Biochemistry, Chiba Cancer Center Research Institute, Chiba 260-8717, Japan
| | - Syunji Hayashi
- Division of Biochemistry, Chiba Cancer Center Research Institute, Chiba 260-8717, Japan
| | - Philip A Barker
- Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Kunio Takano
- Second Department of Surgery, Yamanashi University School of Medicine, Yamanashi 409-3898, Japan
| | - Masahiko Matsumoto
- Second Department of Surgery, Yamanashi University School of Medicine, Yamanashi 409-3898, Japan
| | - Akira Nakagawara
- Division of Biochemistry, Chiba Cancer Center Research Institute, Chiba 260-8717, Japan.
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38
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Abstract
Nuclear factor (NF)-kappaB and inhibitor of NF-kappaB kinase (IKK) proteins regulate many physiological processes, including the innate- and adaptive-immune responses, cell death and inflammation. Disruption of NF-kappaB or IKK function contributes to many human diseases, including cancer. However, the NF-kappaB and IKK pathways do not exist in isolation and there are many mechanisms that integrate their activity with other cell-signalling networks. This crosstalk constitutes a decision-making process that determines the consequences of NF-kappaB and IKK activation and, ultimately, cell fate.
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Affiliation(s)
- Neil D Perkins
- College of Life Sciences, Division of Gene Regulation and Expression, James Black Centre, Dow Street, University of Dundee, Dundee, DD1 5EH, Scotland, UK.
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39
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Solt LA, Madge LA, Orange JS, May MJ. Interleukin-1-induced NF-kappaB activation is NEMO-dependent but does not require IKKbeta. J Biol Chem 2007; 282:8724-33. [PMID: 17244613 PMCID: PMC2824644 DOI: 10.1074/jbc.m609613200] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Activation of NF-kappaB by the pro-inflammatory cytokines tumor necrosis factor (TNF) and interleukin-1 (IL-1) requires the IkappaB kinase (IKK) complex, which contains two kinases named IKKalpha and IKKbeta and a critical regulatory subunit named NEMO. Although we have previously demonstrated that NEMO associates with both IKKs, genetic studies reveal that only its interaction with IKKbeta is required for TNF-induced NF-kappaB activation. To determine whether NEMO and IKKalpha can form a functional IKK complex capable of activating the classical NF-kappaB pathway in the absence of IKKbeta, we utilized a panel of mouse embryonic fibroblasts (MEFs) lacking each of the IKK complex subunits. This confirmed that TNF-induced IkappaBalpha degradation absolutely requires NEMO and IKKbeta. In contrast, we consistently observed intact IkappaBalpha degradation and NF-kappaB activation in response to IL-1 in two separate cell lines lacking IKKbeta. Furthermore, exogenously expressed, catalytically inactive IKKbeta blocked TNF- but not IL-1-induced IkappaBalpha degradation in wild-type MEFs, and reconstitution of IKKalpha/beta double knockout cells with IKKalpha rescued IL-1- but not TNF-induced NF-kappaB activation. Finally, we have shown that incubation of IKKbeta-deficient MEFs with a cell-permeable peptide that blocks the interaction of NEMO with the IKKs inhibits IL-1-induced NF-kappaB activation. Our results therefore demonstrate that NEMO and IKKalpha can form a functional IKK complex that activates the classical NF-kappaB pathway in response to IL-1 but not TNF. These findings further suggest NEMO differentially regulates the fidelity of the IKK subunits activated by distinct upstream signaling pathways.
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Affiliation(s)
- Laura A. Solt
- Department of Animal Biology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania 19104
| | - Lisa A. Madge
- Department of Animal Biology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania 19104
| | - Jordan S. Orange
- Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104
| | - Michael J. May
- Department of Animal Biology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania 19104
- To whom correspondence should be addressed: Dept. of Animal Biology, University of Pennsylvania School of Veterinary Medicine, 3800 Spruce St. (OVH 200E), Philadelphia, PA 19104. Tel.: 215-573-0940; Fax: 215-573-5186;
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40
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Miskolci V, Ghosh CC, Rollins J, Romero C, Vu HY, Robinson S, Davidson D, Vancurova I. TNFalpha release from peripheral blood leukocytes depends on a CRM1-mediated nuclear export. Biochem Biophys Res Commun 2006; 351:354-60. [PMID: 17064665 DOI: 10.1016/j.bbrc.2006.10.045] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2006] [Accepted: 10/05/2006] [Indexed: 10/24/2022]
Abstract
Tumor necrosis factor-alpha (TNFalpha) is a potent pro-inflammatory cytokine that plays a major role in the pathogenesis of acute and chronic inflammatory disorders such as septic shock and arthritis, respectively. Leukocytes stimulated with inflammatory signals such as lipopolysaccharide (LPS) are the predominant producers of TNFalpha, and thus control of TNFalpha release from stimulated leukocytes represents a potential therapeutic target. Here, we report that leptomycin B (LMB), a specific inhibitor of CRM1-dependent nuclear protein export, inhibits TNFalpha release from LPS-stimulated human peripheral blood neutrophils and mononuclear cells. In addition, immunofluorescence confocal microscopy and immunoblotting analysis indicate that TNFalpha is localized in the nucleus of human neutrophils and mononuclear cells. This study demonstrates that the cellular release of TNFalpha from stimulated leukocytes is mediated by the CRM1-dependent nuclear export mechanism. Inhibition of CRM1-dependent cellular release of TNFalpha could thus provide a novel therapeutic approach for disorders involving excessive TNFalpha release.
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41
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Abstract
Transcription factors of the NF-kappaB family regulate hundreds of genes in the context of multiple important physiological and pathological processes. NF-kappaB activation depends on phosphorylation-induced proteolysis of inhibitory IkappaB molecules and NF-kappaB precursors by the ubiquitin-proteasome system. Most of the diverse signaling pathways that activate NF-kappaB converge on IkappaB kinases (IKK), which are essential for signal transmission. Many important details of the composition, regulation and biological function of IKK have been revealed in the last years. This review summarizes current aspects of structure and function of the regular stoichiometric components, the regulatory transient protein interactions of IKK and the mechanisms that contribute to its activation, deactivation and homeostasis. Both phosphorylation and ubiquitinatin (destructive as well as non-destructive) are crucial post-translational events in these processes. In addition to controlling induced IkappaB degradation in the cytoplasm and processing of the NF-kappaB precursor p100, nuclear IKK components have been found to act directly at the chromatin level of induced genes and to mediate responses to DNA damage. Finally, IKK is engaged in cross talk with other pathways and confers functions independently of NF-kappaB.
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42
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Berchtold CM, Wu ZH, Huang TT, Miyamoto S. Calcium-dependent regulation of NEMO nuclear export in response to genotoxic stimuli. Mol Cell Biol 2006; 27:497-509. [PMID: 17074802 PMCID: PMC1800799 DOI: 10.1128/mcb.01772-06] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The mechanisms involved in activation of the transcription factor NF-kappaB by genotoxic agents are not well understood. Previously, we provided evidence that a regulatory subunit of the IkappaB kinase (IKK) complex, NF-kappaB essential modulator (NEMO)/IKKgamma, is a component of a nuclear signal that is generated after DNA damage to mediate NF-kappaB activation. Here, we found that etoposide (VP16) and camptothecin induced increases in intracellular free calcium levels at 60 min after stimulation of CEM T leukemic cells. Inhibition of calcium increases by calcium chelators, BAPTA-AM and EGTA-AM, abrogated NF-kappaB activation by these agents in several cell types examined. Conversely, thapsigargin and ionomycin attenuated the BAPTA-AM effects and promoted NF-kappaB activation by the genotoxic stimuli. Analyses of nuclear NEMO levels in VP16-treated cells suggested that calcium was required for nuclear export of NEMO. Inhibition of the nuclear exporter CRM1 by leptomycin B did not interfere with NEMO nuclear export. Similarly, deficiency of a plausible calcium-dependent nuclear export receptor, calreticulin, failed to prevent NF-kappaB activation by VP16. However, temperature inactivation of the Ran guanine nucleotide exchange factor RCC1 in the tsBN2 cell line harboring a temperature-sensitive mutant of RCC1 blocked NF-kappaB activation induced by genotoxic stimuli. Overexpression of Ran in this cell model showed that DNA damage stimuli induced formation of a complex between Ran and NEMO, suggesting that RCC1 regulated NF-kappaB activation through the modulation of RanGTP. Indeed, evidence for VP16-inducible interaction between Ran-GTP and NEMO could be obtained by means of glutathione S-transferase (GST) pull-down assays using GST fused to the Ran binding domain of RanBP2, which specifically interacts with the GTP-bound form of Ran. BAPTA-AM did not alter these interactions, suggesting that calcium is a necessary step beyond the formation of a Ran-GTP-NEMO complex in the nucleus. These results suggest that calcium has a unique role in genotoxic stress-induced NF-kappaB signaling by regulating nuclear export of NEMO subsequent to the formation of a nuclear export complex composed of Ran-GTP, NEMO, and presumably, an undefined nuclear export receptor.
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Affiliation(s)
- Craig M Berchtold
- Department of Pharmacology, 301 SMI, 1300 University Avenue, University of Wisconsin, Madison, WI 53706, USA
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43
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Habraken Y, Piette J. NF-kappaB activation by double-strand breaks. Biochem Pharmacol 2006; 72:1132-41. [PMID: 16965765 DOI: 10.1016/j.bcp.2006.07.015] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2006] [Revised: 07/10/2006] [Accepted: 07/18/2006] [Indexed: 02/08/2023]
Abstract
Cellular response to DNA damage is complex and relies on the simultaneous activation of different networks. It involves DNA damage recognition, repair, and induction of signalling cascades leading to cell cycle checkpoint activation, apoptosis, and stress related responses. The fate of damaged cells depends on the balance between pro- and antiapoptotic signals. In this decisive life or death choice, the transcription factor NF-kappaB has emerged as a prosurvival actor in most cell types. As corollary, it appears to be associated with tumorigenic process and resistance to therapeutic strategies as it protects cancerous cells from death. In this review, we will focus on NF-kappaB activation by double-strand breaks inducing agents, such as ionizing radiation and DNA topoisomerase I and II inhibitors routinely used in cancer therapy. Coinciding with the 20th anniversary of the NF-kappaB discovery, major steps of the DSB-triggered cascade have been recently identified. Two parallel cascades are necessary for NF-kappaB activation. The first one depends on ATM (activated by double-strand breaks) and the second on PIDD (activated by an unknown stress signal). The phosphorylation of NEMO by ATM is the point of convergence of these two cascades. The identification of ATM/NEMO complex as the long searched "nuclear to cytoplasm" signal leading to IKK activation is also a major piece of the puzzle. The knowledge of the precise steps leading to DSB-initiated NF-kappaB activation will allow the development of specific blocking compounds reducing its prosurvival function.
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Affiliation(s)
- Yvette Habraken
- Unit of Virology and Immunology, Center for Biomedical Integrated Genoproteomics, B23, University of Liège, B-4000 Liège, Belgium.
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44
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Gloire G, Dejardin E, Piette J. Extending the nuclear roles of IkappaB kinase subunits. Biochem Pharmacol 2006; 72:1081-9. [PMID: 16846590 DOI: 10.1016/j.bcp.2006.06.017] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2006] [Revised: 06/02/2006] [Accepted: 06/13/2006] [Indexed: 01/04/2023]
Abstract
The transcription factor NF-kappaB plays a key role in a wide variety of cellular processes such as innate and adaptive immunity, cellular proliferation, apoptosis and development. In unstimulated cells, NF-kappaB is sequestered in the cytoplasm through its tight association with inhibitory proteins called IkappaBs, comprising notably IkappaBalpha. A key step in NF-kappaB activation is the phosphorylation of IkappaBalpha by the so-called IkappaB kinase (IKK) complex, which targets the inhibitory protein for proteasomal degradation and allows the freed NF-kappaB to enter the nucleus where it can transactivate its target genes. The IKK complex is composed of two catalytic subunits called IKKalpha and IKKbeta, and a regulatory subunit called NEMO/IKKgamma. Despite their key role in mediating IkappaBalpha phosphorylation in the cytoplasm, recent works have provided evidence that IKK subunits also translocate into the nucleus to regulate NF-kappaB-dependent and -independent gene expression, paving the way of a novel and exciting field of research. In this review, we will describe the current knowledge in that research area.
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Affiliation(s)
- Geoffrey Gloire
- Center for Biomedical Integrated Genoproteomics (CBIG), Virology and Immunology Unit, Institute of Pathology B23, B-4000 Liège, Belgium
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Liu SF, Malik AB. NF-kappa B activation as a pathological mechanism of septic shock and inflammation. Am J Physiol Lung Cell Mol Physiol 2006; 290:L622-L645. [PMID: 16531564 DOI: 10.1152/ajplung.00477.2005] [Citation(s) in RCA: 564] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The pathophysiology of sepsis and septic shock involves complex cytokine and inflammatory mediator networks. NF-kappaB activation is a central event leading to the activation of these networks. The role of NF-kappaB in septic pathophysiology and the signal transduction pathways leading to NF-kappaB activation during sepsis have been an area of intensive investigation. NF-kappaB is activated by a variety of pathogens known to cause septic shock syndrome. NF-kappaB activity is markedly increased in every organ studied, both in animal models of septic shock and in human subjects with sepsis. Greater levels of NF-kappaB activity are associated with a higher rate of mortality and worse clinical outcome. NF-kappaB mediates the transcription of exceptional large number of genes, the products of which are known to play important roles in septic pathophysiology. Mice deficient in those NF-kappaB-dependent genes are resistant to the development of septic shock and to septic lethality. More importantly, blockade of NF-kappaB pathway corrects septic abnormalities. Inhibition of NF-kappaB activation restores systemic hypotension, ameliorates septic myocardial dysfunction and vascular derangement, inhibits multiple proinflammatory gene expression, diminishes intravascular coagulation, reduces tissue neutrophil influx, and prevents microvascular endothelial leakage. Inhibition of NF-kappaB activation prevents multiple organ injury and improves survival in rodent models of septic shock. Thus NF-kappaB activation plays a central role in the pathophysiology of septic shock.
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Affiliation(s)
- Shu Fang Liu
- Div. of Pulmonary and Critical Care Medicine, Long Island Jewish Medical Center, RM B371, New Hyde Park, NY 11040, USA.
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Hai T, Yeung ML, Wood TG, Wei Y, Yamaoka S, Gatalica Z, Jeang KT, Brasier AR. An alternative splice product of IkappaB kinase (IKKgamma), IKKgamma-delta, differentially mediates cytokine and human T-cell leukemia virus type 1 tax-induced NF-kappaB activation. J Virol 2006; 80:4227-41. [PMID: 16611882 PMCID: PMC1472011 DOI: 10.1128/jvi.80.9.4227-4241.2006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2005] [Accepted: 02/08/2006] [Indexed: 01/30/2023] Open
Abstract
NF-kappaB is an inducible transcription factor mediating innate immune responses whose activity is controlled by the multiprotein IkappaB kinase (IKK) "signalsome". The core IKK consists of two catalytic serine kinases, IKKalpha and IKKbeta, and a noncatalytic subunit, IKKgamma. IKKgamma is required for IKK activity by mediating kinase oligomerization and serving to couple the core catalytic subunits to upstream mitogen-activated protein 3-kinase cascades. We have discovered an alternatively spliced IKKgamma mRNA isoform, encoding an in-frame deletion of exon 5, termed IKKgamma-delta. Using a specific reverse transcription-PCR assay, we find that IKKgamma-delta is widely expressed in cultured human cells and normal human tissues. Because IKKgamma-Delta protein is lacking a critical coiled-coil domain important in protein-protein interactions, we sought to determine its signaling properties by examining its ability to self associate, couple to activators of the canonical pathway, and mediate human T-cell leukemia virus type 1 (HTLV-1) Tax-induced NF-kappaB activity. Coimmunoprecipitation and confocal colocalization assays indicate IKKgamma-delta has strong homo- and heterotypic association with wild-type (WT) IKKgamma and, like IKKgamma WT, associates with the IKKbeta kinase. Similarly, IKKgamma-delta mediates IKK kinase activity and downstream NF-kappaB-dependent transcription in response to tumor necrosis factor (TNF) and the NF-kappaB-inducing kinase-IKKalpha signaling pathway. Surprisingly, however, in contrast to IKKgamma WT, IKKgamma-delta is not able to mediate HTLV-1 Tax-induced NF-kappaB-dependent transcription, even though IKKgamma-delta binds and colocalizes with Tax. These observations suggest that IKKgamma-delta is a functionally distinct alternatively spliced mRNA product differentially mediating TNF-induced, but not Tax-induced, signals converging on the IKK signalsome. Differing levels of IKKgamma-delta expression, therefore, may affect signal transduction cascades coupling to IKK.
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Affiliation(s)
- Tao Hai
- Department of Internal Medicine, The University of Texas Medical Branch, 301 University Blvd., Galveston, Texas 77555-1060, USA
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Lin-Lee YC, Pham LV, Tamayo AT, Fu L, Zhou HJ, Yoshimura LC, Decker GL, Ford RJ. Nuclear localization in the biology of the CD40 receptor in normal and neoplastic human B lymphocytes. J Biol Chem 2006; 281:18878-87. [PMID: 16644731 DOI: 10.1074/jbc.m513315200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
CD40 is a tumor necrosis factor (TNF) receptor superfamily, (TNFR; TNFRSF-5) member, that initiates important signaling pathways mediating cell growth, survival, and differentiation in B-lymphocytes. Although CD40 has been extensively studied as a plasma membrane-associated growth factor receptor, we demonstrate here that CD40 is present not only in the plasma membrane and cytoplasm but also in the nucleus of normal and neoplastic B-lymphoid cells. Confocal microscopy showed that transfected CD40-green fluorescent fusion protein entered B-cell nuclei. The CD40 protein contains a nuclear localization signal sequence that, when mutated, blocks entry of CD40 into the nucleus through the classic karyopherins (importins-alpha/beta) pathway. Nuclear fractionation studies revealed the presence of CD40 protein in the nucleoplasm fraction of activated B cells, and chromatin immunoprecipitation assays demonstrated that CD40 binds to and stimulates the BLyS/BAFF promoter, another TNF family member (TNFSF-13B) involved in cell survival in the B cell lineage. Like other nuclear growth factor receptors, CD40 appears to be a transcriptional regulator and is likely to play a larger and more complex role than previously demonstrated in regulating essential growth and survival pathways in B-lymphocytes.
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Affiliation(s)
- Yen-Chiu Lin-Lee
- Department of Hematopathology, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA
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Kasper LH, Fukuyama T, Biesen MA, Boussouar F, Tong C, de Pauw A, Murray PJ, van Deursen JMA, Brindle PK. Conditional knockout mice reveal distinct functions for the global transcriptional coactivators CBP and p300 in T-cell development. Mol Cell Biol 2006; 26:789-809. [PMID: 16428436 PMCID: PMC1347027 DOI: 10.1128/mcb.26.3.789-809.2006] [Citation(s) in RCA: 164] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The global transcriptional coactivators CREB-binding protein (CBP) and the closely related p300 interact with over 312 proteins, making them among the most heavily connected hubs in the known mammalian protein-protein interactome. It is largely uncertain, however, if these interactions are important in specific cell lineages of adult animals, as homozygous null mutations in either CBP or p300 result in early embryonic lethality in mice. Here we describe a Cre/LoxP conditional p300 null allele (p300flox) that allows for the temporal and tissue-specific inactivation of p300. We used mice carrying p300flox and a CBP conditional knockout allele (CBPflox) in conjunction with an Lck-Cre transgene to delete CBP and p300 starting at the CD4- CD8- double-negative thymocyte stage of T-cell development. Loss of either p300 or CBP led to a decrease in CD4+ CD8+ double-positive thymocytes, but an increase in the percentage of CD8+ single-positive thymocytes seen in CBP mutant mice was not observed in p300 mutants. T cells completely lacking both CBP and p300 did not develop normally and were nonexistent or very rare in the periphery, however. T cells lacking CBP or p300 had reduced tumor necrosis factor alpha gene expression in response to phorbol ester and ionophore, while signal-responsive gene expression in CBP- or p300-deficient macrophages was largely intact. Thus, CBP and p300 each supply a surprising degree of redundant coactivation capacity in T cells and macrophages, although each gene has also unique properties in thymocyte development.
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Affiliation(s)
- Lawryn H Kasper
- Department of Biochemistry, St. Jude Children's Research Hospital, 332 N. Lauderdale, Memphis, TN 38105, USA
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Shirley RB, Kaddour-Djebbar I, Patel DM, Lakshmikanthan V, Lewis RW, Kumar MV. Combination of proteasomal inhibitors lactacystin and MG132 induced synergistic apoptosis in prostate cancer cells. Neoplasia 2006; 7:1104-11. [PMID: 16354593 PMCID: PMC1501172 DOI: 10.1593/neo.05520] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2005] [Revised: 09/30/2005] [Accepted: 10/03/2005] [Indexed: 12/16/2022] Open
Abstract
The proteasome inhibitor Velcade (bortezomib/PS-341) has been shown to block the targeted proteolytic degradation of short-lived proteins that are involved in cell maintenance, growth, division, and death, advocating the use of proteasomal inhibitors as therapeutic agents. Although many studies focused on the use of one proteasomal inhibitor for therapy, we hypothesized that the combination of proteasome inhibitors Lactacystin (AG Scientific, Inc., San Diego CA) and MG132 (Biomol International, Plymouth Meeting, PA) may be more effective in inducing apoptosis. Additionally, this regimen would enable the use of sublethal doses of individual drugs, thus reducing adverse effects. Results indicate a significant increase in apoptosis when LNCaP prostate cancer cells were treated with increasing levels of Lactacystin, MG132, or a combination of sublethal doses of these two inhibitors. Furthermore, induction in apoptosis coincided with a significant loss of IKKalpha, IKKbeta, and IKKgamma proteins and NFkappaB activity. In addition to describing effective therapeutic agents, we provide a model system to facilitate the investigation of the mechanism of action of these drugs and their effects on the IKK-NFkappaB axis.
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Affiliation(s)
- Robert B Shirley
- Department of Urology, Medical College of Georgia, Augusta, GA 30912, USA
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Lamsoul I, Lodewick J, Lebrun S, Brasseur R, Burny A, Gaynor RB, Bex F. Exclusive ubiquitination and sumoylation on overlapping lysine residues mediate NF-kappaB activation by the human T-cell leukemia virus tax oncoprotein. Mol Cell Biol 2005; 25:10391-406. [PMID: 16287853 PMCID: PMC1291224 DOI: 10.1128/mcb.25.23.10391-10406.2005] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The transcription factor NF-kappaB is critical for the induction of cancer, including adult T-cell leukemia, which is linked to infection by human T-cell leukemia virus type 1 and the expression of its regulatory protein Tax. Although activation of the NF-kappaB pathway by Tax involves its interaction with the regulatory subunit of the IkappaB kinase (IKK) complex, NEMO/IKKgamma, the mechanism by which Tax activates specific cellular genes in the nucleus remains unknown. Here, we demonstrate that the attachment of SUMO-1 to Tax regulates its localization in nuclear bodies and the recruitment of both the RelA subunit of NF-kappaB and free IKKgamma in these nuclear structures. However, this sumoylation step is not sufficient for the activation of the NF-kappaB pathway by Tax. This activity requires the prior ubiquitination and colocalization of ubiquitinated Tax with IKK complexes in the cytoplasm and the subsequent migration of the RelA subunit of NF-kappaB to the nucleus. Thus, the ubiquitination and sumoylation of Tax function in concert to result in the migration of RelA to the nucleus and its accumulation with IKKgamma in nuclear bodies for activation of gene expression. These modifications may result in targets for the treatment of adult T-cell leukemia.
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Affiliation(s)
- Isabelle Lamsoul
- Institute for Microbiological Research J-M Wiame, 1 Avenue E. Gryson, B-1070 Brussels, Belgium
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