1
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Song K, Cai X, Dong Y, Wu H, Wei Y, Shankavaram UT, Cui K, Lee Y, Zhu B, Bhattacharjee S, Wang B, Zhang K, Wen A, Wong S, Yu L, Xia L, Welm AL, Bielenberg DR, Camphausen KA, Kang Y, Chen H. Epsins 1 and 2 promote NEMO linear ubiquitination via LUBAC to drive breast cancer development. J Clin Invest 2021; 131:129374. [PMID: 32960814 DOI: 10.1172/jci129374] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 09/17/2020] [Indexed: 12/14/2022] Open
Abstract
Estrogen receptor-negative (ER-negative) breast cancer is thought to be more malignant and devastating than ER-positive breast cancer. ER-negative breast cancer exhibits elevated NF-κB activity, but how this abnormally high NF-κB activity is maintained is poorly understood. The importance of linear ubiquitination, which is generated by the linear ubiquitin chain assembly complex (LUBAC), is increasingly appreciated in NF-κB signaling, which regulates cell activation and death. Here, we showed that epsin proteins, a family of ubiquitin-binding endocytic adaptors, interacted with LUBAC via its ubiquitin-interacting motif and bound LUBAC's bona fide substrate NEMO via its N-terminal homolog (ENTH) domain. Furthermore, epsins promoted NF-κB essential modulator (NEMO) linear ubiquitination and served as scaffolds for recruiting other components of the IκB kinase (IKK) complex, resulting in the heightened IKK activation and sustained NF-κB signaling essential for the development of ER-negative breast cancer. Heightened epsin levels in ER-negative human breast cancer are associated with poor relapse-free survival. We showed that transgenic and pharmacological approaches eliminating epsins potently impeded breast cancer development in both spontaneous and patient-derived xenograft breast cancer mouse models. Our findings established the pivotal role epsins played in promoting breast cancer. Thus, targeting epsins may represent a strategy to restrain NF-κB signaling and provide an important perspective into ER-negative breast cancer treatment.
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Affiliation(s)
- Kai Song
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Xiaofeng Cai
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA.,Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Yunzhou Dong
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Hao Wu
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Yong Wei
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA.,Cancer Metabolism and Growth Program, Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey, USA
| | - Uma T Shankavaram
- Radiation Oncology Branch, National Cancer Institute, Bethesda, Maryland, USA
| | - Kui Cui
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Yang Lee
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Bo Zhu
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Sudarshan Bhattacharjee
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Beibei Wang
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Kun Zhang
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Aiyun Wen
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Scott Wong
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Lili Yu
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Lijun Xia
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Alana L Welm
- Department of Oncological Sciences, University of Utah, Salt Lake City, Utah, USA
| | - Diane R Bielenberg
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Kevin A Camphausen
- Radiation Oncology Branch, National Cancer Institute, Bethesda, Maryland, USA
| | - Yibin Kang
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA.,Cancer Metabolism and Growth Program, Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey, USA
| | - Hong Chen
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
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2
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Zhang C, Huang Y, Li P, Chen X, Liu F, Hou Q. Ginger relieves intestinal hypersensitivity of diarrhea predominant irritable bowel syndrome by inhibiting proinflammatory reaction. BMC Complement Med Ther 2020; 20:279. [PMID: 32928188 PMCID: PMC7489045 DOI: 10.1186/s12906-020-03059-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 08/23/2020] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Ginger or ginger extracts have been used in traditional medicine relieve pain caused by diarrhea predominant irritable bowel syndrome (IBS-D), but few data exists about its effectiveness. This present study was to validate the effect of ginger on visceral pain, and to further explore the possible underlying mechanism by which ginger is used to relieve IBS-D intestinal hypersensitivity. METHODS First, the IBS-D rat model was established by chemical stimulation and acute and chronic pressure stimulation. Then, different dose of ginger were administrated to IBS-D rats and evaluate the defecation frequency, fecal water content (FWC) and abdominal withdrawal reflex (AWR) scores in IBS-D rats. Further, the IBS-D rats were sacrificed to collecte the colonic tissues to evaluate the effect of ginger administration on its pathology and changes of pro-inflammatory factors, and changes of NF-κB pathway. Second, the ginger was taken to HPLC analysis and 6-gingerol was choosen to further experiment. Then, IBS-D rats were treated with different dose of 6-gingerol, and the behavioral evaluation were to evaluate the effect of 6-gingerol on IBS-D rats. Further, colonic epithelial cells (CECs) were collectted and to evaluate the effect of 6-gingerol on the expression of inflammatory factors and changes of NF-κB pathway. RESULTS The IBS-D rat model was successfully established by chemical stimulation and acute and chronic pressure stimulation. And ginger treatment significantly reduced the defecation frequency, fecal water content and AWR scores in IBS-D rats. Histopathological analysis showed that ginger treatment can significantly reduce colonic edema and promote the recovery of inflammation in IBS-D rats, and the effect is equivalent to rifaximin. Elisa and RT-qPCR showed that ginger inhibited the expression of proinflammatory factors (TNF-α, IL-6, iNOS) in IBS-D rats. Western blot showed IkBα was up-regulated while p-p65 was inhibited under ginger treatment. HPLC analysis showed that 6-gingerol was the main component of ginger, which could improve clinical symptoms in IBS-D rats. Western blot and RT-qPCR showed that 6-gingerol inhibited the expression of proinflammatory factors (TNF-α, IL-6, iNOS) in CECs, and inhibition of IκBα degradation and phosphorylation of p65 involved in NF-κB pathway. CONCLUSION Ginger and ginger extract could relieve intestinal hypersensitivity of IBS-D by inhibiting proinflammatory response.
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Affiliation(s)
- Changrong Zhang
- Graduate School, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Yongquan Huang
- Department of Orthopedics, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Peiwu Li
- Department of Gastroenterology, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, 510405, P.R. China
| | - Xinlin Chen
- Department of Preventive Medicine and Health Statistics, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, China
| | - Fengbin Liu
- Department of Gastroenterology, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, 510405, P.R. China.
| | - Qiuke Hou
- Department of Gastroenterology, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, 510405, P.R. China.
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong, China.
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3
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Wang P, Gong P, Wang W, Li J, Ai Y, Zhang X. An Eimeria acervulina OTU protease exhibits linkage-specific deubiquitinase activity. Parasitol Res 2018; 118:47-55. [PMID: 30415394 DOI: 10.1007/s00436-018-6113-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 10/07/2018] [Indexed: 02/03/2023]
Abstract
Ubiquitination is an important post-translational modification process that regulates many cellular processes. Proteins can be modified at single or multiple lysine residues by a single ubiquitin protein or by ubiquitin oligomers. It is important to note that the type of ubiquitin chains determines the functional outcome of the modification. Ubiquitin or ubiquitin chains can be removed by deubiquitinases (DUBs). In our previous study, the Eimeria tenella ovarian tumour (Et-OTU) DUB was shown to regulate the telomerase activity of E. tenella and affect E. tenella proliferation. The amino acid sequences of Et-OTU (GenBank: XP_013229759.1) and Eimeria acervulina (E. acervulina) ovarian tumour (Ea-OTUD3) DUB (XP_013250378.1) are 74% identical. Although Et-OTU may regulate E. tenella telomerase activity, whether Ea-OTUD3 affects E. acervulina growth and reproduction remains unclear. We show here that Ea-OTUD3 belongs to the OTU domain class of cysteine protease deubiquitinating enzymes. Ea-OTUD3 is highly linkage-specific, cleaving K48 (Lys48)-, K63-, and K6-linked diubiquitin but not K29-, K33-, and K11-linked diubiquitin. The precise linkage preference of Ea-OTUD3 among these three nonlinear diubiquitin chains is K6 > K48 > K63. Recombinant Ea-OTUD3, but not its catalytic-site mutant Ea-OTUD3 (C247A), exhibits activity against diubiquitin. Ea-OTUD3 removes ubiquitin from the K48-, but to a lesser extent from the K63-linked ubiquitinated E. acervulina proteins of the modified target protein, thereby exhibiting the characteristics of deubiquitinase. This study reveals that the Ea-OTUD3 is a novel functional deubiquitinating enzyme. Furthermore, the Ea-OTUD3 protein may regulate the stability of some K48-linked ubiquitinated E. acervulina proteins.
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Affiliation(s)
- Pu Wang
- College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Pengtao Gong
- College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Weirong Wang
- College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Jianhua Li
- College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Yongxing Ai
- College of Animal Science, Jilin University, Changchun, 130062, China.
| | - Xichen Zhang
- College of Veterinary Medicine, Jilin University, Changchun, 130062, China.
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4
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Modulation of adenylate cyclase signaling in association with MKK3/6 stabilization under combination of SAC and berberine to reduce HepG2 cell survivability. Apoptosis 2018; 22:1362-1379. [PMID: 28836036 DOI: 10.1007/s10495-017-1407-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Cancer cells often have faulty apoptotic pathways resulting in sustenance of survivability, tumour metastasis and resistance to anticancer drugs. Alternate strategies are sought to improve therapeutic efficacy and therefore HepG2 cells were treated with S-allyl-cysteine (SAC) and berberine (BER) to analyze their mechanistic impact upon necroptosis along with its interacting relationship to apoptosis. In the present study we observed that SAC and BER exposure reduced NFκβ nuclear translocation through adenylate cyclase-cAMP-protein kinaseA axis and eventually evaded c-FLIP inhibition. Effective RIP1 k63-polyubiquitination and persistent MKK3/MKK6 expression during drug treatment potentiated caspase8 activity via p53-DISC conformation. Resultant tBid associated lysosomal protease mediated AIF truncation induced DNA fragmentation and persuaded effector caspase mediated scramblase activation resulting induction of necroptosis in parallel to apoptotic events. SAC+BER effectively reduced Rb-phosphorylation resulting insignificant nuclear E2F presence led to ending of cell proliferation. Therefore necroptosis augmented the drug response and may be targeted alongside cell proliferation inhibition in formation of efficient therapeutics against liver cancer.
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5
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Chishti AA, Baumstark-Khan C, Koch K, Kolanus W, Feles S, Konda B, Azhar A, Spitta LF, Henschenmacher B, Diegeler S, Schmitz C, Hellweg CE. Linear Energy Transfer Modulates Radiation-Induced NF-kappa B Activation and Expression of its Downstream Target Genes. Radiat Res 2018; 189:354-370. [DOI: 10.1667/rr14905.1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Arif Ali Chishti
- German Aerospace Centre (DLR), Institute of Aerospace Medicine, Radiation Biology Department, Linder Höhe, D-51147 Köln, Germany
| | - Christa Baumstark-Khan
- German Aerospace Centre (DLR), Institute of Aerospace Medicine, Radiation Biology Department, Linder Höhe, D-51147 Köln, Germany
| | - Kristina Koch
- German Aerospace Centre (DLR), Institute of Aerospace Medicine, Radiation Biology Department, Linder Höhe, D-51147 Köln, Germany
| | - Waldemar Kolanus
- Life and Medical Sciences (LIMES) Institute, University of Bonn, Karlrobert-Kreiten-Straße 13, 53115 Bonn, Germany
| | - Sebastian Feles
- German Aerospace Centre (DLR), Institute of Aerospace Medicine, Radiation Biology Department, Linder Höhe, D-51147 Köln, Germany
| | - Bikash Konda
- German Aerospace Centre (DLR), Institute of Aerospace Medicine, Radiation Biology Department, Linder Höhe, D-51147 Köln, Germany
| | - Abid Azhar
- The Karachi Institute of Biotechnology and Genetic Engineering, University of Karachi, Karachi-75270, Pakistan
| | - Luis F. Spitta
- German Aerospace Centre (DLR), Institute of Aerospace Medicine, Radiation Biology Department, Linder Höhe, D-51147 Köln, Germany
| | - Bernd Henschenmacher
- German Aerospace Centre (DLR), Institute of Aerospace Medicine, Radiation Biology Department, Linder Höhe, D-51147 Köln, Germany
| | - Sebastian Diegeler
- German Aerospace Centre (DLR), Institute of Aerospace Medicine, Radiation Biology Department, Linder Höhe, D-51147 Köln, Germany
| | - Claudia Schmitz
- German Aerospace Centre (DLR), Institute of Aerospace Medicine, Radiation Biology Department, Linder Höhe, D-51147 Köln, Germany
| | - Christine E. Hellweg
- German Aerospace Centre (DLR), Institute of Aerospace Medicine, Radiation Biology Department, Linder Höhe, D-51147 Köln, Germany
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6
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Lentucci C, Belkina AC, Cederquist CT, Chan M, Johnson HE, Prasad S, Lopacinski A, Nikolajczyk BS, Monti S, Snyder-Cappione J, Tanasa B, Cardamone MD, Perissi V. Inhibition of Ubc13-mediated Ubiquitination by GPS2 Regulates Multiple Stages of B Cell Development. J Biol Chem 2016; 292:2754-2772. [PMID: 28039360 DOI: 10.1074/jbc.m116.755132] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 12/21/2016] [Indexed: 12/12/2022] Open
Abstract
Non-proteolytic ubiquitin signaling mediated by Lys63 ubiquitin chains plays a critical role in multiple pathways that are key to the development and activation of immune cells. Our previous work indicates that GPS2 (G-protein Pathway Suppressor 2) is a multifunctional protein regulating TNFα signaling and lipid metabolism in the adipose tissue through modulation of Lys63 ubiquitination events. However, the full extent of GPS2-mediated regulation of ubiquitination and the underlying molecular mechanisms are unknown. Here, we report that GPS2 is required for restricting the activation of TLR and BCR signaling pathways and the AKT/FOXO1 pathway in immune cells based on direct inhibition of Ubc13 enzymatic activity. Relevance of this regulatory strategy is confirmed in vivo by B cell-targeted deletion of GPS2, resulting in developmental defects at multiple stages of B cell differentiation. Together, these findings reveal that GPS2 genomic and non-genomic functions are critical for the development and cellular homeostasis of B cells.
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Affiliation(s)
| | - Anna C Belkina
- the Flow Cytometry Core Facility, Boston University School of Medicine, Boston, Massachusetts 02118 and.,Microbiology, and
| | | | | | | | | | | | | | | | - Jennifer Snyder-Cappione
- the Flow Cytometry Core Facility, Boston University School of Medicine, Boston, Massachusetts 02118 and.,Microbiology, and
| | - Bogdan Tanasa
- the Department of Pediatrics, Stanford University School of Medicine, Stanford, California 94305
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7
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Dey P, Panga V, Raghunathan S. A Cytokine Signalling Network for the Regulation of Inducible Nitric Oxide Synthase Expression in Rheumatoid Arthritis. PLoS One 2016; 11:e0161306. [PMID: 27626941 PMCID: PMC5023176 DOI: 10.1371/journal.pone.0161306] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 08/03/2016] [Indexed: 12/22/2022] Open
Abstract
In rheumatoid arthritis (RA), nitric oxide (NO) is implicated in inflammation, angiogenesis and tissue destruction. The enzyme inducible nitric oxide synthase (iNOS) is responsible for the localised over-production of NO in the synovial joints affected by RA. The pro- and anti-inflammatory cytokines stimulate the synovial macrophages and the fibroblast-like synoviocytes to express iNOS. Therefore, the cytokine signalling network underlying the regulation of iNOS is essential to understand the pathophysiology of the disease. By using information from the literature, we have constructed, for the first time, the cytokine signalling network involved in the regulation of iNOS expression. Using the differential expression patterns obtained by re-analysing the microarray data on the RA synovium and the synovial macrophages available in the Gene Expression Omnibus (GEO) database, we aimed to establish the role played by the network genes towards iNOS regulation in the RA synovium. Our analysis reveals that the network genes belonging to interferon (IFN) and interleukin-10 (IL-10) pathways are always up-regulated in the RA synovium whereas the genes which are part of the anti-inflammatory transforming growth factor-beta (TGF-β) signalling pathway are mostly down-regulated. We observed a consistent up-regulation of the transcription factor signal transducers and activators of transcription 1 (STAT1) in the RA synovium and the macrophages. Interestingly, we found a consistent up-regulation of the iNOS interacting protein ras-related C3 botulinum toxin substrate 2 (RAC2) in the RA synovium as well as the macrophages. Importantly, we have constructed a model to explain the impact of IFN and IL-10 pathways on Rac2-iNOS interaction leading to over-production of NO and thereby causing chronic inflammation in the RA synovium. The interplay between STAT1 and RAC2 in the regulation of NO could have implications for the identification of therapeutic targets for RA.
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Affiliation(s)
- Poulami Dey
- Institute of Bioinformatics and Applied Biotechnology (IBAB), Biotech Park, Electronics City Phase I, Bengaluru 560 100, Karnataka, India
- Manipal University, Manipal, 576104, Karnataka, India
| | - Venugopal Panga
- Institute of Bioinformatics and Applied Biotechnology (IBAB), Biotech Park, Electronics City Phase I, Bengaluru 560 100, Karnataka, India
- Manipal University, Manipal, 576104, Karnataka, India
| | - Srivatsan Raghunathan
- Institute of Bioinformatics and Applied Biotechnology (IBAB), Biotech Park, Electronics City Phase I, Bengaluru 560 100, Karnataka, India
- * E-mail:
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8
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Hellweg CE, Spitta LF, Henschenmacher B, Diegeler S, Baumstark-Khan C. Transcription Factors in the Cellular Response to Charged Particle Exposure. Front Oncol 2016; 6:61. [PMID: 27047795 PMCID: PMC4800317 DOI: 10.3389/fonc.2016.00061] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 03/03/2016] [Indexed: 12/23/2022] Open
Abstract
Charged particles, such as carbon ions, bear the promise of a more effective cancer therapy. In human spaceflight, exposure to charged particles represents an important risk factor for chronic and late effects such as cancer. Biological effects elicited by charged particle exposure depend on their characteristics, e.g., on linear energy transfer (LET). For diverse outcomes (cell death, mutation, transformation, and cell-cycle arrest), an LET dependency of the effect size was observed. These outcomes result from activation of a complex network of signaling pathways in the DNA damage response, which result in cell-protective (DNA repair and cell-cycle arrest) or cell-destructive (cell death) reactions. Triggering of these pathways converges among others in the activation of transcription factors, such as p53, nuclear factor κB (NF-κB), activated protein 1 (AP-1), nuclear erythroid-derived 2-related factor 2 (Nrf2), and cAMP responsive element binding protein (CREB). Depending on dose, radiation quality, and tissue, p53 induces apoptosis or cell-cycle arrest. In low LET radiation therapy, p53 mutations are often associated with therapy resistance, while the outcome of carbon ion therapy seems to be independent of the tumor's p53 status. NF-κB is a central transcription factor in the immune system and exhibits pro-survival effects. Both p53 and NF-κB are activated after ionizing radiation exposure in an ataxia telangiectasia mutated (ATM)-dependent manner. The NF-κB activation was shown to strongly depend on charged particles' LET, with a maximal activation in the LET range of 90-300 keV/μm. AP-1 controls proliferation, senescence, differentiation, and apoptosis. Nrf2 can induce cellular antioxidant defense systems, CREB might also be involved in survival responses. The extent of activation of these transcription factors by charged particles and their interaction in the cellular radiation response greatly influences the destiny of the irradiated and also neighboring cells in the bystander effect.
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Affiliation(s)
- Christine E. Hellweg
- Cellular Biodiagnostics, Department of Radiation Biology, Institute of Aerospace Medicine, German Aerospace Centre (DLR), Cologne, Germany
| | - Luis F. Spitta
- Cellular Biodiagnostics, Department of Radiation Biology, Institute of Aerospace Medicine, German Aerospace Centre (DLR), Cologne, Germany
| | - Bernd Henschenmacher
- Cellular Biodiagnostics, Department of Radiation Biology, Institute of Aerospace Medicine, German Aerospace Centre (DLR), Cologne, Germany
| | - Sebastian Diegeler
- Cellular Biodiagnostics, Department of Radiation Biology, Institute of Aerospace Medicine, German Aerospace Centre (DLR), Cologne, Germany
| | - Christa Baumstark-Khan
- Cellular Biodiagnostics, Department of Radiation Biology, Institute of Aerospace Medicine, German Aerospace Centre (DLR), Cologne, Germany
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9
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Zhang L, Blackwell K, Workman LM, Gibson-Corley KN, Olivier AK, Bishop GA, Habelhah H. TRAF2 exerts opposing effects on basal and TNFα-induced activation of the classic IKK complex in hematopoietic cells in mice. J Cell Sci 2016; 129:1455-67. [PMID: 26872784 DOI: 10.1242/jcs.180554] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 02/08/2016] [Indexed: 12/19/2022] Open
Abstract
The role of TRAF2 and TRAF5 in TNFα-induced NF-κB activation has become complicated owing to the accumulation of conflicting data. Here, we report that 7-day-old TRAF2-knockout (KO) and TRAF2 TRAF5 double KO (TRAF2/5-DKO) mice exhibit enhanced canonical IκB kinase (IKK) and caspase-8 activation in spleen and liver, and that subsequent knockout of TNFα suppresses the basal activity of caspase-8, but not of IKK. In primary TRAF2 KO and TRAF2/5-DKO cells, TNFα-induced immediate IKK activation is impaired, whereas delayed IKK activation occurs normally; as such, owing to elevated basal and TNFα-induced delayed IKK activation, TNFα stimulation leads to significantly increased induction of a subset of NF-κB-dependent genes in these cells. In line with this, both TRAF2 KO and TRAF2/5-DKO mice succumb to a sublethal dose of TNFα owing to increased expression of NF-κB target genes, diarrhea and bradypnea. Notably, depletion of IAP1 and IAP2 (also known as BIRC2 and BIRC3, respectively) also results in elevated basal IKK activation that is independent of autocrine TNFα production and that impairs TNFα-induced immediate IKK activation. These data reveal that TRAF2, IAP1 and IAP2, but not TRAF5, cooperatively regulate basal and TNFα-induced immediate IKK activation.
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Affiliation(s)
- Laiqun Zhang
- Department of Pathology, Carver College of Medicine, University of Iowa, and the Iowa City Veterans Affairs Medical Center, Iowa City, IA 52242, USA
| | - Ken Blackwell
- Department of Pathology, Carver College of Medicine, University of Iowa, and the Iowa City Veterans Affairs Medical Center, Iowa City, IA 52242, USA
| | - Lauren M Workman
- Department of Pathology, Carver College of Medicine, University of Iowa, and the Iowa City Veterans Affairs Medical Center, Iowa City, IA 52242, USA
| | - Katherine N Gibson-Corley
- Department of Pathology, Carver College of Medicine, University of Iowa, and the Iowa City Veterans Affairs Medical Center, Iowa City, IA 52242, USA
| | - Alicia K Olivier
- Department of Pathology, Carver College of Medicine, University of Iowa, and the Iowa City Veterans Affairs Medical Center, Iowa City, IA 52242, USA
| | - Gail A Bishop
- Department of Microbiology & Internal Medicine, Carver College of Medicine, University of Iowa, and the Iowa City Veterans Affairs Medical Center, Iowa City, IA 52242, USA
| | - Hasem Habelhah
- Department of Pathology, Carver College of Medicine, University of Iowa, and the Iowa City Veterans Affairs Medical Center, Iowa City, IA 52242, USA
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10
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Tumor Necrosis Factor Receptor Associated Factors (TRAFs) 2 and 3 Form a Transcriptional Complex with Phosho-RNA Polymerase II and p65 in CD40 Ligand Activated Neuro2a Cells. Mol Neurobiol 2016; 54:1301-1313. [PMID: 26843107 PMCID: PMC5310569 DOI: 10.1007/s12035-016-9742-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 01/22/2016] [Indexed: 12/23/2022]
Abstract
The tumor necrosis factor receptor-associated factors (TRAFs) have been classically described as adaptor proteins that function as solely cytosolic signaling intermediates for the TNF receptor superfamily, Toll-like receptors (TLRs), NOD, like receptors (NLRs), cytokine receptors, and others. In this study, we show for the first time that TRAFs are present within the cytoplasm and nucleus of Neuro2a cells and primary cortical neurons, and that TRAF2 and TRAF3 translocate into the nucleus within minutes of CD40L stimulation. Analysis of the transcriptional regulatory potential of TRAFs by luciferase assay revealed that each of the TRAFs differentially functions as a transcriptional activator or repressor in a cell-specific manner. Interestingly, ChIP-qPCR data demonstrate that TRAFs 2/3, p65, and pRNAPol II form part of a transcriptional complex on the Icam-1 gene promoter upon CD40L stimulation. We further determined that TRAF2 recruitment to the nucleus is critical for the ubiquitination of H2b, a transcription permissive epigenetic modification. Our findings demonstrate for the first time that TRAFs 2/3 participate in the formation of a CD40L-induced transcriptional complex in neuronal cells.
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11
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Aminabadi NA, Behroozian A, Talatahari E, Samiei M, Sadigh-Eteghad S, Shirazi S. Does prenatal restraint stress change the craniofacial growth pattern of rat offspring? Eur J Oral Sci 2015; 124:17-25. [PMID: 26620628 DOI: 10.1111/eos.12230] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/14/2015] [Indexed: 12/18/2022]
Abstract
A major and frequently encountered condition underlying the long-term programming effects of the intrauterine environment is exposure to stress. Gestational stress is an environmental factor that induces physical and behavioral alterations in offspring. Seventy female virgin Wistar rats were mated with one male rat for a maximum of four times, after which 52 pregnant rats were divided into two groups. In the experimental group the rats were exposed to restraint stress during pregnancy, whereas the control group did not receive the stress protocol. One male litter was randomly chosen from the offspring of each rat with 8-13 pups. A total of 40 male rat offspring were available for analysis. Thirty-one linear and angular measurements were analyzed in both study groups to investigate whether prenatal restraint stress changes the craniofacial growth pattern of rat offspring. In the prenatally stressed group, anterior cranial base length and viscerocranium measures were significantly increased compared with the control group, whereas cranial width, mandibular dimensions, and posterior cranial height and length remained unchanged. Furthermore, the prenatally stressed group showed backward rotation of the midface and decreased flattening of the cranial vault. It was concluded that prenatal chronic stress can induce alterations in the craniofacial growth pattern by promoting endochondral growth in the cranial base and nasal septum.
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Affiliation(s)
- Naser A Aminabadi
- Department of Pediatric Dentistry, Faculty of Dentistry, Tabriz University of Medical Science, Tabriz, Iran
| | - Ahmad Behroozian
- Department of Orthodontics, Faculty of Dentistry, Tabriz University of Medical Science, Tabriz, Iran
| | - Elham Talatahari
- Department of Pediatric Dentistry, Faculty of Dentistry, Tabriz University of Medical Science, Tabriz, Iran
| | - Mohammad Samiei
- Department of Endodontic and Medical Nanotechnology, Faculty of Dentistry and Advanced Medical Sciences, Tabriz University of Medical Science, Tabriz, Iran
| | - Saeed Sadigh-Eteghad
- Neuroscience Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Sajjad Shirazi
- Dental and Periodental Research Centre, Tabriz University of Medical Sciences, Tabriz, Iran
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12
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Hellweg CE. The Nuclear Factor κB pathway: A link to the immune system in the radiation response. Cancer Lett 2015; 368:275-89. [DOI: 10.1016/j.canlet.2015.02.019] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 02/08/2015] [Accepted: 02/10/2015] [Indexed: 01/01/2023]
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13
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Ho YK, Zhi H, Bowlin T, Dorjbal B, Philip S, Zahoor MA, Shih HM, Semmes OJ, Schaefer B, Glover JNM, Giam CZ. HTLV-1 Tax Stimulates Ubiquitin E3 Ligase, Ring Finger Protein 8, to Assemble Lysine 63-Linked Polyubiquitin Chains for TAK1 and IKK Activation. PLoS Pathog 2015; 11:e1005102. [PMID: 26285145 PMCID: PMC4540474 DOI: 10.1371/journal.ppat.1005102] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 07/21/2015] [Indexed: 11/29/2022] Open
Abstract
Human T lymphotropic virus type 1 (HTLV-1) trans-activator/oncoprotein, Tax, impacts a multitude of cellular processes, including I-κB kinase (IKK)/NF-κB signaling, DNA damage repair, and mitosis. These activities of Tax have been implicated in the development of adult T-cell leukemia (ATL) in HTLV-1-infected individuals, but the underlying mechanisms remain obscure. IKK and its upstream kinase, TGFβ-activated kinase 1 (TAK1), contain ubiquitin-binding subunits, NEMO and TAB2/3 respectively, which interact with K63-linked polyubiquitin (K63-pUb) chains. Recruitment to K63-pUb allows cross auto-phosphorylation and activation of TAK1 to occur, followed by TAK1-catalyzed IKK phosphorylation and activation. Using cytosolic extracts of HeLa and Jurkat T cells supplemented with purified proteins we have identified ubiquitin E3 ligase, ring finger protein 8 (RNF8), and E2 conjugating enzymes, Ubc13:Uev1A and Ubc13:Uev2, to be the cellular factors utilized by Tax for TAK1 and IKK activation. In vitro, the combination of Tax and RNF8 greatly stimulated TAK1, IKK, IκBα and JNK phosphorylation. In vivo, RNF8 over-expression augmented while RNF8 ablation drastically reduced canonical NF-κB activation by Tax. Activation of the non-canonical NF-κB pathway by Tax, however, is unaffected by the loss of RNF8. Using purified components, we further demonstrated biochemically that Tax greatly stimulated RNF8 and Ubc13:Uev1A/Uev2 to assemble long K63-pUb chains. Finally, co-transfection of Tax with increasing amounts of RNF8 greatly induced K63-pUb assembly in a dose-dependent manner. Thus, Tax targets RNF8 and Ubc13:Uev1A/Uev2 to promote the assembly of K63-pUb chains, which signal the activation of TAK1 and multiple downstream kinases including IKK and JNK. Because of the roles RNF8 and K63-pUb chains play in DNA damage repair and cytokinesis, this mechanism may also explain the genomic instability of HTLV-1-transformed T cells and ATL cells. Activation of the NF-κB family of transcription factors by the HTLV-1 oncoprotein, Tax, is causally linked to adult T cell leukemia (ATL) development in HTLV-1-infected individuals, but the underlying mechanisms are not fully understood. NF-κB activation requires the phosphorylation of its inhibitor, IκBα, by IκB kinase (IKK), which marks IκBα for degradation. In this study, we demonstrate that Tax inappropriately activates a ubiquitin E3 ligase, RNF8, and ubiquitin E2 conjugating enzymes, Ubc13:Uev1A/Uev2, to assemble long lysine 63-linked polyubiquitin (K63-pUb) chains, which function as signaling platforms for polyubiquitin-binding TGFβ-activated kinase 1 (TAK1) and IKK to congregate and become activated. Because TAK1 mediates the activation of multiple downstream signaling pathways, the mechanism described here can explain the complex effect of Tax on cell signaling. The major functions of RNF8 are to signal cellular DNA damage repair (DDR) and cell division by assembling K63-pUb chains at the site of DNA damage and cell cleavage. As such, the inappropriate activation of RNF8 and the over-abundance of K63-pUb chains in Tax-expressing cells may explain how Tax causes DNA damage and cell division defect.
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Affiliation(s)
- Yik-Khuan Ho
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America
| | - Huijun Zhi
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America
| | - Tara Bowlin
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America
| | - Batsukh Dorjbal
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America
| | - Subha Philip
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America
| | - Muhammad Atif Zahoor
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America
| | - Hsiu-Ming Shih
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Oliver John Semmes
- Department of Microbiology and Molecular Cell Biology, The Leroy T. Canoles Jr. Cancer Research Center, Eastern Virginia Medical School, Norfolk, Virginia, United States of America
| | - Brian Schaefer
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America
| | - J. N. Mark Glover
- Department of Biochemistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Chou-Zen Giam
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America
- * E-mail:
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14
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The class II transactivator (CIITA) is regulated by post-translational modification cross-talk between ERK1/2 phosphorylation, mono-ubiquitination and Lys63 ubiquitination. Biosci Rep 2015; 35:BSR20150091. [PMID: 26181363 PMCID: PMC4613680 DOI: 10.1042/bsr20150091] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 06/11/2015] [Indexed: 02/01/2023] Open
Abstract
The class II transactivator (CIITA) is known as the master regulator for the major histocompatibility class II (MHC II) molecules. CIITA is dynamically regulated through a series of intricate post-translational modifications (PTMs). CIITA's role is to initiate transcription of MHC II genes, which are responsible for presenting extracellular antigen to CD4(+) T-cells. In the present study, we identified extracellular signal-regulated kinase (ERK)1/2 as the kinase responsible for phosphorylating the regulatory site, Ser(280), which leads to increased levels of mono-ubiquitination and an overall increase in MHC II activity. Further, we identify that CIITA is also modified by Lys(63)-linked ubiquitination. Lys(63) ubiquitinated CIITA is concentrated in the cytoplasm and following activation of ERK1/2, CIITA phosphorylation occurs and Lys=ubiquitinated CIITA translocates to the nucleus. CIITA ubiquitination and phosphorylation perfectly demonstrates how CIITA location and activity is regulated through PTM cross-talk. Identifying CIITA PTMs and understanding how they mediate CIITA regulation is necessary due to the critical role CIITA has in the initiation of the adaptive immune response.
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15
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Sorokin AV, Nair BC, Wei Y, Aziz KE, Evdokimova V, Hung MC, Chen J. Aberrant Expression of proPTPRN2 in Cancer Cells Confers Resistance to Apoptosis. Cancer Res 2015; 75:1846-58. [PMID: 25877877 DOI: 10.1158/0008-5472.can-14-2718] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 02/01/2015] [Indexed: 01/09/2023]
Abstract
The protein tyrosine phosphatase receptor PTPRN2 is expressed predominantly in endocrine and neuronal cells, where it functions in exocytosis. We found that its immature isoform proPTPRN2 is overexpressed in various cancers, including breast cancer. High proPTPRN2 expression was associated strongly with lymph node-positive breast cancer and poor clinical outcome. Loss of proPTPRN2 in breast cancer cells promoted apoptosis and blocked tumor formation in mice, whereas enforced expression of proPTPRN2 in nontransformed human mammary epithelial cells exerted a converse effect. Mechanistic investigations suggested that ProPTPRN2 elicited these effects through direct interaction with TRAF2, a hub scaffold protein for multiple kinase cascades, including ones that activate NF-κB. Overall, our results suggest PTPRN2 as a novel candidate biomarker and therapeutic target in breast cancer.
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Affiliation(s)
- Alexey V Sorokin
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Binoj C Nair
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Yongkun Wei
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Kathryn E Aziz
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Valentina Evdokimova
- Department of Genomics, Ontario Institute for Cancer Research, Toronto, Ontario, Canada
| | - Mien-Chie Hung
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas. Center for Molecular Medicine and Graduate Institute of Cancer Biology, China Medical University, Taichung, Taiwan
| | - Junjie Chen
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
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16
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Gao L, Tang W, Ding Z, Wang D, Qi X, Wu H, Guo J. Protein-Binding Function of RNA-Dependent Protein Kinase Promotes Proliferation through TRAF2/RIP1/NF-κB/c-Myc Pathway in Pancreatic β cells. Mol Med 2015; 21:154-66. [PMID: 25715336 DOI: 10.2119/molmed.2014.00235] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Accepted: 02/18/2015] [Indexed: 12/29/2022] Open
Abstract
Double-stranded RNA-dependent protein kinase (PKR), an intracellular pathogen recognition receptor, is involved both in insulin resistance in peripheral tissues and in downregulation of pancreatic β-cell function in a kinase-dependent manner, indicating PKR as a core component in the progression of type 2 diabetes. PKR also acts as an adaptor protein via its protein-binding domain. Here, the PKR protein-binding function promoted β-cell proliferation without its kinase activity, which is associated with enhanced physical interaction with tumor necrosis factor receptor-associated factor 2 (TRAF2) and TRAF6. In addition, the transcription of the nuclear factor kappa-light-chain-enhancer of activated B cell (NF-κB)-dependent survival gene c-Myc was upregulated significantly and is necessary for proliferation. Upregulation of the PKR protein-binding function induced the NF-κB pathway, as observed by dose-dependent degradation of IκBα, induced nuclear translocation of p65 and elevated NF-κB-dependent reporter gene expression. NF-κB-dependent reporter activity and β-cell proliferation both were suppressed by TRAF2-siRNA, but not by TRAF6-siRNA. TRAF2-siRNA blocked the ubiquitination of receptor-interacting serine/threonine-protein kinase 1 (RIP1) induced by PKR protein binding. Furthermore, RIP1-siRNA inhibited β-cell proliferation. Proinflammatory cytokines (TNFα) and glucolipitoxicity also promoted the physical interaction of PKR with TRAF2. Collectively, these data indicate a pivotal role for PKR's protein-binding function on the proliferation of pancreatic β cells through TRAF2/RIP1/NF-κB/c-Myc pathways. Therapeutic opportunities for type 2 diabetes may arise when its kinase catalytic function, but not its protein-binding function, is downregulated.
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Affiliation(s)
- Lili Gao
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Nanjing Medical University, Nanjing, People's Republic of China.,Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, People's Republic of China
| | - Wei Tang
- Department of Endocrinology, The Affiliated Jiangyin Hospital of Southeast University Medical College, Jiangyin, People's Republic of China
| | - ZhengZheng Ding
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Nanjing Medical University, Nanjing, People's Republic of China.,Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, People's Republic of China
| | - DingYu Wang
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Nanjing Medical University, Nanjing, People's Republic of China.,Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, People's Republic of China
| | - XiaoQiang Qi
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Nanjing Medical University, Nanjing, People's Republic of China.,Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, People's Republic of China
| | - HuiWen Wu
- Laboratory Center for Basic Medical Sciences, Nanjing Medical University, Nanjing, People's Republic of China
| | - Jun Guo
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Nanjing Medical University, Nanjing, People's Republic of China.,Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, People's Republic of China
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17
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Tomar D, Singh R. TRIM family proteins: emerging class of RING E3 ligases as regulator of NF-κB pathway. Biol Cell 2014; 107:22-40. [DOI: 10.1111/boc.201400046] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Accepted: 10/06/2014] [Indexed: 12/22/2022]
Affiliation(s)
- Dhanendra Tomar
- Department of Cell Biology; School of Biological Sciences and Biotechnology; Indian Institute of Advanced Research; Gandhinagar India
| | - Rajesh Singh
- Department of Biochemistry; Faculty of Science; The M.S. University of Baroda; Vadodara 390 002 Gujarat India
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18
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High doses of CpG oligodeoxynucleotides stimulate a tolerogenic TLR9-TRIF pathway. Nat Commun 2013; 4:1852. [PMID: 23673637 DOI: 10.1038/ncomms2874] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 04/12/2013] [Indexed: 02/07/2023] Open
Abstract
CpG-rich oligodeoxynucleotides activate the immune system, leading to innate and acquired immune responses. The immune-stimulatory effects of CpG-rich oligodeoxynucleotides are being exploited as a therapeutic approach. Here we show that at high doses, CpG-rich oligodeoxynucleotides promote an opposite, tolerogenic response in mouse plasmacytoid dendritic cells in vivo and in a human in vitro model. Unveiling a previously undescribed role for TRIF and TRAF6 proteins in Toll-like receptor 9 (TLR9) signalling, we demonstrate that physical association of TLR9, TRIF and TRAF6 leads to activation of noncanonical NF-κB signalling and the induction of IRF3- and TGF-β-dependent immune-suppressive tryptophan catabolism. In vivo, the TLR9-TRIF circuit--but not MyD88 signalling--was required for CpG protection against allergic inflammation. Our findings may be relevant to an increased understanding of the complexity of Toll-like receptor signalling and optimal exploitation of CpG-rich oligodeoxynucleotides as immune modulators.
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Abstract
At least 468 individual genes have been manipulated by molecular methods to study their effects on the initiation, promotion, and progression of atherosclerosis. Most clinicians and many investigators, even in related disciplines, find many of these genes and the related pathways entirely foreign. Medical schools generally do not attempt to incorporate the relevant molecular biology into their curriculum. A number of key signaling pathways are highly relevant to atherogenesis and are presented to provide a context for the gene manipulations summarized herein. The pathways include the following: the insulin receptor (and other receptor tyrosine kinases); Ras and MAPK activation; TNF-α and related family members leading to activation of NF-κB; effects of reactive oxygen species (ROS) on signaling; endothelial adaptations to flow including G protein-coupled receptor (GPCR) and integrin-related signaling; activation of endothelial and other cells by modified lipoproteins; purinergic signaling; control of leukocyte adhesion to endothelium, migration, and further activation; foam cell formation; and macrophage and vascular smooth muscle cell signaling related to proliferation, efferocytosis, and apoptosis. This review is intended primarily as an introduction to these key signaling pathways. They have become the focus of modern atherosclerosis research and will undoubtedly provide a rich resource for future innovation toward intervention and prevention of the number one cause of death in the modern world.
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Affiliation(s)
- Paul N Hopkins
- Cardiovascular Genetics, Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA.
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20
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Abstract
The tumor necrosis factor receptor (TNF-R)-associated factor (TRAF) family of intracellular proteins were originally identified as signaling adaptors that bind directly to the cytoplasmic regions of receptors of the TNF-R superfamily. The past decade has witnessed rapid expansion of receptor families identified to employ TRAFs for signaling. These include Toll-like receptors (TLRs), NOD-like receptors (NLRs), RIG-I-like receptors (RLRs), T cell receptor, IL-1 receptor family, IL-17 receptors, IFN receptors and TGFβ receptors. In addition to their role as adaptor proteins, most TRAFs also act as E3 ubiquitin ligases to activate downstream signaling events. TRAF-dependent signaling pathways typically lead to the activation of nuclear factor-κBs (NF-κBs), mitogen-activated protein kinases (MAPKs), or interferon-regulatory factors (IRFs). Compelling evidence obtained from germ-line and cell-specific TRAF-deficient mice demonstrates that each TRAF plays indispensable and non-redundant physiological roles, regulating innate and adaptive immunity, embryonic development, tissue homeostasis, stress response, and bone metabolism. Notably, mounting evidence implicates TRAFs in the pathogenesis of human diseases such as cancers and autoimmune diseases, which has sparked new appreciation and interest in TRAF research. This review presents an overview of the current knowledge of TRAFs, with an emphasis on recent findings concerning TRAF molecules in signaling and in human diseases.
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Affiliation(s)
- Ping Xie
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Nelson Labs Room B336, Piscataway, New Jersey 08854.
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21
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Workman LM, Habelhah H. TNFR1 signaling kinetics: spatiotemporal control of three phases of IKK activation by posttranslational modification. Cell Signal 2013; 25:1654-64. [PMID: 23612498 DOI: 10.1016/j.cellsig.2013.04.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 04/15/2013] [Indexed: 12/24/2022]
Abstract
TNFα is a pleotropic cytokine that plays a central role in the inflammatory response by activating the NF-κB signaling pathway, and is targeted in a range of chronic inflammatory diseases, underscoring the therapeutic importance of understanding its underlying molecular mechanisms. Although K63-linked ubiquitination of RIP1 by TRAF2/5 and cIAP1/2 was thought to serve as a scaffold to activate the NF-κB pathway, the recent accumulation of conflicting results has challenged the necessity of these proteins in NF-κB activation. In addition, several serine/threonine kinases have been implicated in TNFα-induced IKK activation; however, the targeted disruption of these kinases had no effect on transient IKK activation. The recent discovery of RIP1-dependent and -independent activation of the early and delayed phases of IKK and TRAF2 phosphorylation-dependent activation of the prolonged phase of IKK offers a reconciliatory model for the interpretation of contradictory results in the field. Notably, the TNFα-induced inflammatory response is not exclusively controlled by the NF-κB pathway but is subject to regulatory crosstalk between NF-κB and other context-dependent pathways. Thus further elucidation of these spatiotemporally-coordinated signaling mechanisms has the potential to provide novel molecular targets and therapeutic strategies for NF-κB intervention.
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Affiliation(s)
- Lauren M Workman
- Interdisciplinary Graduate Program in Molecular and Cellular Biology, University of Iowa, Iowa City, IA 52242, USA
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22
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Chen BB, Coon TA, Glasser JR, McVerry BJ, Zhao J, Zhao Y, Zou C, Ellis B, Sciurba FC, Zhang Y, Mallampalli RK. A combinatorial F box protein directed pathway controls TRAF adaptor stability to regulate inflammation. Nat Immunol 2013; 14:470-9. [PMID: 23542741 PMCID: PMC3631463 DOI: 10.1038/ni.2565] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 01/31/2013] [Indexed: 01/19/2023]
Abstract
Uncontrolled activation of tumor necrosis factor receptor-associated factor (TRAF) proteins may result in profound tissue injury by linking surface signals to cytokine release. Here we show that a ubiquitin E3 ligase component, Fbxo3, potently stimulates cytokine secretion from human inflammatory cells by destabilizing a sentinel TRAF inhibitor, Fbxl2. Fbxo3 and TRAF protein in circulation positively correlated with cytokine responses in septic subjects and we furthermore identified a hypofunctional Fbxo3 human polymorphism. A small molecule inhibitor targeting Fbxo3 was sufficient to lessen severity of cytokine-driven inflammation in several murine disease models. These studies identify a pathway of innate immunity that may characterize subjects with altered immune responses during critical illness or provide a basis for therapeutic intervention targeting TRAF protein abundance.
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Affiliation(s)
- Bill B Chen
- Department of Medicine, Acute Lung Injury Center of Excellence, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
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23
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Humphrey RK, Yu SMA, Bellary A, Gonuguntla S, Yebra M, Jhala US. Lysine 63-linked ubiquitination modulates mixed lineage kinase-3 interaction with JIP1 scaffold protein in cytokine-induced pancreatic β cell death. J Biol Chem 2013; 288:2428-40. [PMID: 23172226 PMCID: PMC3554912 DOI: 10.1074/jbc.m112.425884] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2012] [Revised: 11/16/2012] [Indexed: 12/14/2022] Open
Abstract
The mixed lineage kinase MLK3 plays a crucial role in compromising mitochondrial integrity and functions as a proapoptotic competence factor in the early stages of cytokine-induced pancreatic β cell death. In an effort to identify mechanisms that regulate MLK3 activity in β cells, we discovered that IL-1β stimulates Lys-63-linked ubiquitination of MLK3 via a conserved, TRAF6-binding peptapeptide motif in the catalytic domain of the kinase. TRAF6-mediated ubiquitination was required for dissociation of inactive monomeric MLK3 from the scaffold protein IB1/JIP1, facilitating the subsequent dimerization, autophosphorylation, and catalytic activation of MLK3. Inability to ubiquitinate MLK3, or the presence of A20, an upstream Lys-63-linked deubiquitinase, strongly curtailed the ability of MLK3 to affect the proapoptotic translocation of BAX in cytokine-stimulated pancreatic β cells, an early step in the progression toward β cell death. These studies suggest a novel mechanism for MLK3 activation and provide new clues for therapeutic intervention in promoting β cell survival.
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Affiliation(s)
- Rohan K. Humphrey
- From the Pediatric Diabetes Research Center, University of California, San Diego, School of Medicine, La Jolla, California 92037
| | - Shu Mei A. Yu
- From the Pediatric Diabetes Research Center, University of California, San Diego, School of Medicine, La Jolla, California 92037
| | - Aditi Bellary
- From the Pediatric Diabetes Research Center, University of California, San Diego, School of Medicine, La Jolla, California 92037
| | - Sumati Gonuguntla
- From the Pediatric Diabetes Research Center, University of California, San Diego, School of Medicine, La Jolla, California 92037
| | - Myra Yebra
- From the Pediatric Diabetes Research Center, University of California, San Diego, School of Medicine, La Jolla, California 92037
| | - Ulupi S. Jhala
- From the Pediatric Diabetes Research Center, University of California, San Diego, School of Medicine, La Jolla, California 92037
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24
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Fiandalo M, Kyprianou N. Caspase control: protagonists of cancer cell apoptosis. Exp Oncol 2012; 34:165-175. [PMID: 23070001 PMCID: PMC3721730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Emergence of castration-resistant metastatic prostate cancer is due to activation of survival pathways, including apoptosis suppression and anoikis resistance, and increased neovascularization. Thus targeting of apoptotic players is of critical significance in prostate cancer therapy since loss of apoptosis and resistance to anoikis are critical in aberrant malignant growth, metastasis and conferring therapeutic failure. The majority of therapeutic agents act through intrinsic mitochondrial, extrinsic death receptor pathways or endoplasmic reticulum stress pathways to induce apoptosis. Current therapeutic strategies target restoring regulatory molecules that govern the pro-survival pathways such as PTEN which regulates AKT activity. Other strategies focus on reactivating the apoptotic pathways either by down-regulating anti-apoptotic players such as BCL-2 or by up-regulating pro-apoptotic protein families, most notably, the caspases. Caspases are a family of cystine proteases which serve critical roles in apoptotic and inflammatory signaling pathways. During tumorigenesis, significant loss or inactivation of lead members in the caspase family leads to impairing apoptosis induction, causing a dramatic imbalance in the growth dynamics, ultimately resulting in aberrant growth of human cancers. Recent exploitation of apoptosis pathways towards re-instating apoptosis induction via caspase re-activation has provided new molecular platforms for the development of therapeutic strategies effective against advanced prostate cancer as well as other solid tumors. This review will discuss the current cellular landscape featuring the caspase family in tumor cells and their activation via pharmacologic intervention towards optimized anti-cancer therapeutic modalities. This article is part of a Special Issue entitled "Apoptosis: Four Decades Later".
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25
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HTLV-1 tax-induced rapid senescence is driven by the transcriptional activity of NF-κB and depends on chronically activated IKKα and p65/RelA. J Virol 2012; 86:9474-83. [PMID: 22740410 DOI: 10.1128/jvi.00158-12] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The HTLV-1 oncoprotein Tax is a potent activator of classical and alternative NF-κB pathways and is thought to promote cell proliferation and transformation via NF-κB activation. We showed recently that hyperactivation of NF-κB by Tax triggers a cellular senescence response (H. Zhi et al., PLoS Pathog. 7:e1002025, 2011). Inhibition of NF-κB activation by expression of I-κBα superrepressor or by small hairpin RNA (shRNA)-mediated knockdown of p65/RelA rescues cells from Tax-induced rapid senescence (Tax-IRS). Here we demonstrate that Tax-IRS is driven by the transcriptional activity of NF-κB. Knockdown of IKKγ, the primary Tax target, by shRNAs abrogated Tax-mediated activation of both classical and alternative NF-κB pathways and rendered knockdown cells resistant to Tax-IRS. Consistent with a critical role of IKKα in the transcriptional activity of NF-κB, IKKα deficiency drastically decreased NF-κB trans-activation by Tax, although it only modestly reduced Tax-mediated I-κBα degradation and NF-κB nuclear localization. In contrast, although IKKβ knockdown attenuated Tax-induced NF-κB transcriptional activation, the residual NF-κB activation in IKKβ-deficient cells was sufficient to trigger Tax-IRS. Importantly, the phenotypes of NIK and TAK1 knockdown were similar to those of IKKα and IKKβ knockdown, respectively. Finally, double knockdown of RelB and p100 had a minor effect on senescence induction by Tax. These data suggest that Tax, through its interaction with IKKγ, helps recruit NIK and TAK1 for IKKα and IKKβ activation, respectively. In the presence of Tax, the delineation between the classical and alternative NF-κB pathways becomes obscured. The senescence checkpoint triggered by Tax is driven by the transcriptional activity of NF-κB, which depends on activated IKKα and p65/RelA.
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26
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A protective strategy against hyperinflammatory responses requiring the nontranscriptional actions of GPS2. Mol Cell 2012; 46:91-104. [PMID: 22424771 DOI: 10.1016/j.molcel.2012.01.025] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2011] [Revised: 09/07/2011] [Accepted: 01/24/2012] [Indexed: 02/08/2023]
Abstract
The association between hyperinflammatory states and numerous diseases is widely recognized, but our understanding of the molecular strategies that have evolved to prevent uncontrolled activation of inflammatory responses remains incomplete. Here, we report a critical, nontranscriptional role of GPS2 as a guardian against hyperstimulation of the TNF-α-induced gene program. GPS2 cytoplasmic actions are required to specifically modulate RIP1 ubiquitylation and JNK activation by inhibiting TRAF2/Ubc13 enzymatic activity. In vivo relevance of GPS2 anti-inflammatory role is confirmed by inhibition of TNF-α target genes in macrophages and by improved insulin signaling in the adipose tissue of aP2-GPS2 transgenic mice. As the nontranscriptional role is complemented by GPS2 functioning as positive and negative cofactor for nuclear receptors, in vivo overexpression also results in elevated circulating level of Resistin and development of hepatic steatosis. Together, these studies define GPS2 as a molecular guardian required for precise control of inflammatory responses involved in immunity and homeostasis.
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Specific recognition of linear ubiquitin chains by the Npl4 zinc finger (NZF) domain of the HOIL-1L subunit of the linear ubiquitin chain assembly complex. Proc Natl Acad Sci U S A 2011; 108:20520-5. [PMID: 22139374 DOI: 10.1073/pnas.1109088108] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The linear ubiquitin chain assembly complex (LUBAC) is a key nuclear factor-κB (NF-κB) pathway component that produces linear polyubiquitin chains. The HOIL-1L subunit of LUBAC has been shown to bind linear chains; however, detailed structural and functional analyses on the binding between LUBAC and linear chains have not been performed. In this study, we found that the Npl4 zinc finger (NZF) domain of HOIL-1L specifically binds linear polyubiquitin chains and determined the crystal structure of the HOIL-1L NZF domain in complex with linear diubiquitin at 1.7-Å resolution. The HOIL-1L NZF domain consists of a zinc-coordinating "NZF core" region and an additional α-helical "NZF tail" region. The HOIL-1L NZF core binds both the canonical Ile44-centered hydrophobic surface on the distal ubiquitin and a Phe4-centered hydrophobic patch on the proximal ubiquitin, representing a mechanism for the specific recognition of linear chains. The NZF tail binds the proximal ubiquitin to enhance the binding affinity. These recognition mechanisms were supported by the accompanying in vitro and in vivo structure-based mutagenesis experiments.
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Ruchaud-Sparagano MH, Mühlen S, Dean P, Kenny B. The enteropathogenic E. coli (EPEC) Tir effector inhibits NF-κB activity by targeting TNFα receptor-associated factors. PLoS Pathog 2011; 7:e1002414. [PMID: 22144899 PMCID: PMC3228809 DOI: 10.1371/journal.ppat.1002414] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Accepted: 10/20/2011] [Indexed: 01/08/2023] Open
Abstract
Enteropathogenic Escherichia coli (EPEC) disease depends on the transfer of effector proteins into epithelia lining the human small intestine. EPEC E2348/69 has at least 20 effector genes of which six are located with the effector-delivery system genes on the Locus of Enterocyte Effacement (LEE) Pathogenicity Island. Our previous work implied that non-LEE-encoded (Nle) effectors possess functions that inhibit epithelial anti-microbial and inflammation-inducing responses by blocking NF-κB transcription factor activity. Indeed, screens by us and others have identified novel inhibitory mechanisms for NleC and NleH, with key co-operative functions for NleB1 and NleE1. Here, we demonstrate that the LEE-encoded Translocated-intimin receptor (Tir) effector has a potent and specific ability to inhibit NF-κB activation. Indeed, biochemical, imaging and immunoprecipitation studies reveal a novel inhibitory mechanism whereby Tir interaction with cytoplasm-located TNFα receptor-associated factor (TRAF) adaptor proteins induces their proteasomal-independent degradation. Infection studies support this Tir-TRAF relationship but reveal that Tir, like NleC and NleH, has a non-essential contribution in EPEC's NF-κB inhibitory capacity linked to Tir's activity being suppressed by undefined EPEC factors. Infections in a disease-relevant intestinal model confirm key NF-κB inhibitory roles for the NleB1/NleE1 effectors, with other studies providing insights on host targets. The work not only reveals a second Intimin-independent property for Tir and a novel EPEC effector-mediated NF-κB inhibitory mechanism but also lends itself to speculations on the evolution of EPEC's capacity to inhibit NF-κB function.
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Affiliation(s)
| | - Sabrina Mühlen
- Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle-upon-Tyne, United Kingdom
| | - Paul Dean
- Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle-upon-Tyne, United Kingdom
| | - Brendan Kenny
- Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle-upon-Tyne, United Kingdom
- * E-mail:
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