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Dai J, Dong X, Chen Y, Xue W, Wang Q, Shang F, Zhao Y, Li S, Gao Y, Wang Y. SPOP regulates the expression profiles and alternative splicing events in human hepatocytes. Open Life Sci 2023; 18:20220755. [PMID: 37941785 PMCID: PMC10628592 DOI: 10.1515/biol-2022-0755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 09/08/2023] [Accepted: 09/19/2023] [Indexed: 11/10/2023] Open
Abstract
Speckle type BTB/POZ protein (SPOP) may have cancer promoting or inhibiting effects. At present, the role of SPOP in hepatocellular carcinoma (HCC) has rarely been studied. In this study, to investigate the effects of SPOP in HCC and elucidate the underlying molecular mechanisms of its relationship with genes, differentially expressed genes (DEGs) were classified through RNA sequencing. The gene ontology analysis and Kyoto Encyclopedia of Genes and Genomes functional pathway analysis were used to further predict the function of DEGs after the overexpression of SPOP. The biological function of SPOP-regulated alternative splicing events in cells is comprehensively assessed. The Cancer Genome Atlas database and Gene Expression Omnibus dataset were performed to evaluate the correlation between SPOP and HCC progression. Due to SPOP overexpression, 56 DEGs in the HCC related pathway were further identified. The results showed that SPOP overexpression facilitated the cell proliferation and changed the gene expression profiles of human normal hepatocytes. SPOP-regulated alternative splicing events were involved in pathways associated with cellular processes, metabolism, environmental information procession, organismal systems, and so on. In conclusion, SPOP may potentially exhibit tumor-promoting effects, necessitating further investigations to unveil its molecular mechanisms comprehensively.
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Affiliation(s)
- Jing Dai
- School of Life Science, Bengbu Medical College, No. 2600 Donghai Road, Bengbu, China
| | - Xiang Dong
- School of Life Science, Bengbu Medical College, No. 2600 Donghai Road, Bengbu, China
- Research Center of Clinical Laboratory Science, School of Laboratory Medicine, Bengbu Medical College, Bengbu, China
| | - Yuxin Chen
- School of Life Science, Bengbu Medical College, No. 2600 Donghai Road, Bengbu, China
| | - Wanying Xue
- School of Life Science, Bengbu Medical College, No. 2600 Donghai Road, Bengbu, China
| | - Qingqing Wang
- School of Life Science, Bengbu Medical College, No. 2600 Donghai Road, Bengbu, China
| | - Feifei Shang
- School of Life Science, Bengbu Medical College, No. 2600 Donghai Road, Bengbu, China
| | - Yunxia Zhao
- Department of Basic Medical College, Bengbu Medical College, Bengbu, Anhui, China
| | - Shujing Li
- School of Life Science, Bengbu Medical College, No. 2600 Donghai Road, Bengbu, China
| | - Yu Gao
- School of Life Science, Bengbu Medical College, No. 2600 Donghai Road, Bengbu, China
- Anhui Province Key Laboratory of Translational Cancer Research, Bengbu Medical College, No. 2600 Donghai Road, Bengbu, Anhui, China
| | - Yuanyuan Wang
- School of Life Science, Bengbu Medical College, No. 2600 Donghai Road, Bengbu, China
- Anhui Province Key Laboratory of Translational Cancer Research, Bengbu Medical College, No. 2600 Donghai Road, Bengbu, Anhui, China
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2
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Amhaz S, Boëda B, Chouchène M, Colasse S, Dingli F, Loew D, Henri J, Prunier C, Levy L. The UAS thioredoxin-like domain of UBXN7 regulates E3 ubiquitin ligase activity of RNF111/Arkadia. BMC Biol 2023; 21:73. [PMID: 37024974 PMCID: PMC10080908 DOI: 10.1186/s12915-023-01576-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 03/24/2023] [Indexed: 04/08/2023] Open
Abstract
BACKGROUND E3 ubiquitin ligases play critical roles in regulating cellular signaling pathways by inducing ubiquitylation of key components. RNF111/Arkadia is a RING E3 ubiquitin ligase that activates TGF-β signaling by inducing ubiquitylation and proteasomal degradation of the transcriptional repressor SKIL/SnoN. In this study, we have sought to identify novel regulators of the E3 ubiquitin ligase activity of RNF111 by searching for proteins that specifically interacts with its RING domain. RESULTS We found that UBXN7, a member of the UBA-UBX family, directly interacts with the RING domain of RNF111 or its related E3 RNF165/ARK2C that shares high sequence homology with RNF111. We showed that UBXN7 docks on RNF111 or RNF165 RING domain through its UAS thioredoxin-like domain. Overexpression of UBXN7 or its UAS domain increases endogenous RNF111, while an UBXN7 mutant devoid of UAS domain has no effect. Conversely, depletion of UBXN7 decreases RNF111 protein level. As a consequence, we found that UBXN7 can modulate degradation of the RNF111 substrate SKIL in response to TGF-β signaling. We further unveiled this mechanism of regulation by showing that docking of the UAS domain of UBXN7 inhibits RNF111 ubiquitylation by preventing interaction of the RING domain with the E2 conjugating enzymes. By analyzing the interactome of the UAS domain of UBXN7, we identified that it also interacts with the RING domain of the E3 TOPORS and similarly regulates its E3 ubiquitin ligase activity by impairing E2 binding. CONCLUSIONS Taken together, our results demonstrate that UBXN7 acts as a direct regulator for the E3 ubiquitin ligases RNF111, RNF165, and TOPORS and reveal that a thioredoxin-like domain can dock on specific RING domains to regulate their E3 ubiquitin ligase activity.
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Affiliation(s)
- Sadek Amhaz
- Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine, CRSA, 75012, Paris, France
| | - Batiste Boëda
- Cell Polarity, Migration and Cancer Unit, Institut Pasteur, UMR3691 CNRS, Université Paris Cité, F-75015, Paris, France
| | - Mouna Chouchène
- Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine, CRSA, 75012, Paris, France
| | - Sabrina Colasse
- Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine, CRSA, 75012, Paris, France
| | - Florent Dingli
- CurieCoreTech Mass Spectrometry Proteomics, Institut Curie, PSL Research University, Paris, France
| | - Damarys Loew
- CurieCoreTech Mass Spectrometry Proteomics, Institut Curie, PSL Research University, Paris, France
| | - Julien Henri
- Sorbonne Université, CNRS, IBPS, Laboratoire de Biologie Computationnelle et Quantitative - UMR 7238, 75005, Paris, France
| | - Céline Prunier
- Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine, CRSA, 75012, Paris, France.
| | - Laurence Levy
- Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine, CRSA, 75012, Paris, France.
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3
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Ogami T, Tamura Y, Toss K, Yuki K, Morikawa M, Tsutsumi S, Aburatani H, Miyazawa K, Miyazono K, Koinuma D. MAB21L4 regulates the TGF-β-induced expression of target genes in epidermal keratinocytes. J Biochem 2021; 171:399-410. [PMID: 34908107 PMCID: PMC8969751 DOI: 10.1093/jb/mvab141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 12/10/2021] [Indexed: 11/26/2022] Open
Abstract
Smad proteins transduce signals downstream of transforming growth factor-β (TGF-β) and are one of the factors that regulate the expression of genes related to diseases affecting the skin. In the present study, we identified MAB21L4, also known as male abnormal 21 like 4 or C2orf54, as the most up-regulated targets of TGF-β and Smad3 in differentiated human progenitor epidermal keratinocytes using chromatin immunoprecipitation sequencing
(ChIP-seq) and RNA sequencing (RNA-seq). We found that TGF-β induced expression of the barrier protein involucrin (encoded by the IVL gene). Transcriptional activity of the IVL promoter induced by TGF-β was inhibited by MAB21L4 siRNAs. Further analysis revealed that MAB21L4 siRNAs also down-regulated the expression of several target genes of TGF-β. MAB21L4 protein was located mainly in the cytosol, where it was physically bound to Smad3 and a transcriptional corepressor c-Ski. siRNAs for MAB21L4 did not inhibit the binding of Smad3 to their target genomic regions but down-regulated the acetylation of histone H3 lys 27 (H3K27ac), an active histone mark, near the Smad3 binding regions. These findings suggest that TGF-β-induced MAB21L4 up-regulates the gene expression induced by TGF-β, possibly through the inhibition of c-Ski via physical interaction in the cytosol.
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Affiliation(s)
- Tomohiro Ogami
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yusuke Tamura
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Kim Toss
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Keiko Yuki
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Masato Morikawa
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Shuichi Tsutsumi
- Genome Science Division, Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Meguro-ku, Tokyo 153-8904, Japan
| | - Hiroyuki Aburatani
- Genome Science Division, Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Meguro-ku, Tokyo 153-8904, Japan
| | - Keiji Miyazawa
- Department of Biochemistry, Graduate School of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi 409-3898, Japan
| | - Kohei Miyazono
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Daizo Koinuma
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
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4
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Hokari S, Tamura Y, Kaneda A, Katsura A, Morikawa M, Murai F, Ehata S, Tsutsumi S, Ishikawa Y, Aburatani H, Kikuchi T, Miyazono K, Koinuma D. Comparative analysis of TTF-1 binding DNA regions in small-cell lung cancer and non-small-cell lung cancer. Mol Oncol 2019; 14:277-293. [PMID: 31782890 PMCID: PMC6998394 DOI: 10.1002/1878-0261.12608] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 11/07/2019] [Accepted: 11/27/2019] [Indexed: 12/14/2022] Open
Abstract
Thyroid transcription factor-1 (TTF-1, encoded by the NKX2-1 gene) is highly expressed in small-cell lung carcinoma (SCLC) and lung adenocarcinoma (LADC), but how its functional roles differ between SCLC and LADC remains to be elucidated. Here, we compared the genome-wide distributions of TTF-1 binding regions and the transcriptional programs regulated by TTF-1 between NCI-H209 (H209), a human SCLC cell line, and NCI-H441 (H441), a human LADC cell line, using chromatin immunoprecipitation-sequencing (ChIP-seq) and RNA-sequencing (RNA-seq). TTF-1 binding regions in H209 and H441 cells differed by 75.0% and E-box motifs were highly enriched exclusively in the TTF-1 binding regions of H209 cells. Transcriptome profiling revealed that TTF-1 is involved in neuroendocrine differentiation in H209 cells. We report that TTF-1 and achaete-scute homolog 1 (ASCL1, also known as ASH1, an E-box binding basic helix-loop-helix transcription factor, and a lineage-survival oncogene of SCLC) are coexpressed and bound to adjacent sites on target genes expressed in SCLC, and cooperatively regulate transcription. Furthermore, TTF-1 regulated expression of the Bcl-2 gene family and showed antiapoptotic function in SCLC. Our findings suggest that TTF-1 promotes SCLC growth and contributes to neuroendocrine and antiapoptotic gene expression by partly coordinating with ASCL1.
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Affiliation(s)
- Satoshi Hokari
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Japan.,Department of Respiratory Medicine and Infectious Diseases, Niigata University Graduate School of Medical and Dental Sciences, Japan
| | - Yusuke Tamura
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Japan
| | - Atsushi Kaneda
- Department of Molecular Oncology, Graduate School of Medicine, Chiba University, Japan
| | - Akihiro Katsura
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Japan
| | - Masato Morikawa
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Japan
| | - Fumihiko Murai
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Japan
| | - Shogo Ehata
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Japan
| | - Shuichi Tsutsumi
- Genome Science Division, Research Center for Advanced Science and Technology, The University of Tokyo, Japan
| | - Yuichi Ishikawa
- Division of Pathology, the Cancer Institute Hospital, Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Hiroyuki Aburatani
- Genome Science Division, Research Center for Advanced Science and Technology, The University of Tokyo, Japan
| | - Toshiaki Kikuchi
- Department of Respiratory Medicine and Infectious Diseases, Niigata University Graduate School of Medical and Dental Sciences, Japan
| | - Kohei Miyazono
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Japan
| | - Daizo Koinuma
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Japan
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5
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Li L, Wang G, Hu JS, Zhang GQ, Chen HZ, Yuan Y, Li YL, Lv XJ, Tian FY, Pan SH, Bai XW, Sun B. RB1CC1-enhanced autophagy facilitates PSCs activation and pancreatic fibrogenesis in chronic pancreatitis. Cell Death Dis 2018; 9:952. [PMID: 30237496 PMCID: PMC6147947 DOI: 10.1038/s41419-018-0980-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 08/21/2018] [Accepted: 08/23/2018] [Indexed: 12/13/2022]
Abstract
Chronic pancreatitis (CP) is described as a progressive fibro-inflammatory disorder of the exocrine disease, which eventually leads to damage of the gland. Excessive activation of pancreatic stellate cells (PSCs) is a critical participant in the initiation of CP. Autophagy is involved in multiple degeneration and inflammation in acute pancreatitis and CP. In our study, we report that retinoblastoma coiled coil protein 1 (RB1CC1) expression and the autophagic level are elevated in activated PSCs. RB1CC1 is positively correlated with pancreatic fibrogenesis in tissues and plasma of CP patients. Knockdown of RB1CC1 restrains alpha smooth muscle actin (α-SMA) and collagen expressions, and autophagy in activated PSCs in vitro. Furthermore, we show that RB1CC1 induces PSC activation via binding to ULK1 promoter and the direct interaction with ULK1 protein. These suppress ULK1 expression and its kinase activity. In mice, knockdown of RB1CC1 blocks autophagy and then inhibits the pancreatic duct ligation-induced pancreatic fibrosis. Consequently, our study highlights that RB1CC1-mediated autophagy is a key event for the activation of PSCs. Inhibition of RB1CC1 alleviates autophagy, which plays a critical role in anti-fibrotic activation in PSCs and CP progression. RB1CC1 could be a novel strategy for the treatment of pancreatic fibrosis.
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Affiliation(s)
- Le Li
- Department of Pancreatic and Biliary Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
| | - Gang Wang
- Department of Pancreatic and Biliary Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
| | - Ji-Sheng Hu
- Department of Pancreatic and Biliary Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
| | - Guang-Quan Zhang
- Department of Pancreatic and Biliary Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
| | - Hong-Ze Chen
- Department of Pancreatic and Biliary Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
| | - Yue Yuan
- Department of Cardiology, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
| | - Yi-Long Li
- Department of Pancreatic and Biliary Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
| | - Xin-Jian Lv
- Department of Pancreatic and Biliary Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
| | - Feng-Yu Tian
- Department of Pancreatic and Biliary Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
| | - Shang-Ha Pan
- Department of Pancreatic and Biliary Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China.,Key Laboratory of Hepatosplenic Surgery, Ministry of Education, Department of General Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
| | - Xue-Wei Bai
- Department of Pancreatic and Biliary Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
| | - Bei Sun
- Department of Pancreatic and Biliary Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China.
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6
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Tecalco-Cruz AC, Ríos-López DG, Vázquez-Victorio G, Rosales-Alvarez RE, Macías-Silva M. Transcriptional cofactors Ski and SnoN are major regulators of the TGF-β/Smad signaling pathway in health and disease. Signal Transduct Target Ther 2018; 3:15. [PMID: 29892481 PMCID: PMC5992185 DOI: 10.1038/s41392-018-0015-8] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 02/16/2018] [Accepted: 03/15/2018] [Indexed: 12/19/2022] Open
Abstract
The transforming growth factor-β (TGF-β) family plays major pleiotropic roles by regulating many physiological processes in development and tissue homeostasis. The TGF-β signaling pathway outcome relies on the control of the spatial and temporal expression of >500 genes, which depend on the functions of the Smad protein along with those of diverse modulators of this signaling pathway, such as transcriptional factors and cofactors. Ski (Sloan-Kettering Institute) and SnoN (Ski novel) are Smad-interacting proteins that negatively regulate the TGF-β signaling pathway by disrupting the formation of R-Smad/Smad4 complexes, as well as by inhibiting Smad association with the p300/CBP coactivators. The Ski and SnoN transcriptional cofactors recruit diverse corepressors and histone deacetylases to repress gene transcription. The TGF-β/Smad pathway and coregulators Ski and SnoN clearly regulate each other through several positive and negative feedback mechanisms. Thus, these cross-regulatory processes finely modify the TGF-β signaling outcome as they control the magnitude and duration of the TGF-β signals. As a result, any alteration in these regulatory mechanisms may lead to disease development. Therefore, the design of targeted therapies to exert tight control of the levels of negative modulators of the TGF-β pathway, such as Ski and SnoN, is critical to restore cell homeostasis under the specific pathological conditions in which these cofactors are deregulated, such as fibrosis and cancer. Proteins that repress molecular signaling through the transforming growth factor-beta (TGF-β) pathway offer promising targets for treating cancer and fibrosis. Marina Macías-Silva and colleagues from the National Autonomous University of Mexico in Mexico City review the ways in which a pair of proteins, called Ski and SnoN, interact with downstream mediators of TGF-β to inhibit the effects of this master growth factor. Aberrant levels of Ski and SnoN have been linked to diverse range of diseases involving cell proliferation run amok, and therapies that regulate the expression of these proteins could help normalize TGF-β signaling to healthier physiological levels. For decades, drug companies have tried to target the TGF-β pathway, with limited success. Altering the activity of these repressors instead could provide a roundabout way of remedying pathogenic TGF-β activity in fibrosis and oncology.
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Affiliation(s)
- Angeles C Tecalco-Cruz
- 1Instituto de Investigaciones Biomédicas at Universidad Nacional Autónoma de México, Mexico city, 04510 Mexico
| | - Diana G Ríos-López
- 2Instituto de Fisiología Celular at Universidad Nacional Autónoma de México, Mexico city, 04510 Mexico
| | | | - Reyna E Rosales-Alvarez
- 2Instituto de Fisiología Celular at Universidad Nacional Autónoma de México, Mexico city, 04510 Mexico
| | - Marina Macías-Silva
- 2Instituto de Fisiología Celular at Universidad Nacional Autónoma de México, Mexico city, 04510 Mexico
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7
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Abstract
Discovery of yeast autophagy-related (ATG) genes and subsequent identification of their homologs in other organisms have enabled researchers to investigate physiological functions of macroautophagy/autophagy using genetic techniques. Specific identification of autophagy-related structures is important to evaluate autophagic activity, and specific ablation of autophagy-related genes is a critical means to determine the requirements of autophagy. Here, we review currently available mouse models, particularly focusing on autophagy (and mitophagy) indicator models and systemic autophagy-related gene-knockout mouse models.
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Affiliation(s)
- Akiko Kuma
- Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, The University of Tokyo, Tokyo, Japan
- Division of Cancer Biology, National Cancer Center Research Institute, Tokyo, Japan
- CONTACT Akiko Kuma Division of Cancer Biology, National Cancer Center Research Institute, 5-1-1 Tsukiji Chuo-ku, Tokyo 104-0045 Japan
| | - Masaaki Komatsu
- Department of Biochemistry, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Noboru Mizushima
- Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, The University of Tokyo, Tokyo, Japan
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8
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Katsura A, Tamura Y, Hokari S, Harada M, Morikawa M, Sakurai T, Takahashi K, Mizutani A, Nishida J, Yokoyama Y, Morishita Y, Murakami T, Ehata S, Miyazono K, Koinuma D. ZEB1-regulated inflammatory phenotype in breast cancer cells. Mol Oncol 2017; 11:1241-1262. [PMID: 28618162 PMCID: PMC5579340 DOI: 10.1002/1878-0261.12098] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 06/04/2017] [Indexed: 12/20/2022] Open
Abstract
Zinc finger E‐box binding protein 1 (ZEB1) and ZEB2 induce epithelial‐mesenchymal transition (EMT) and enhance cancer progression. However, the global view of transcriptional regulation by ZEB1 and ZEB2 is yet to be elucidated. Here, we identified a ZEB1‐regulated inflammatory phenotype in breast cancer cells using chromatin immunoprecipitation sequencing and RNA sequencing, followed by gene set enrichment analysis (GSEA) of ZEB1‐bound genes. Knockdown of ZEB1 and/or ZEB2 resulted in the downregulation of genes encoding inflammatory cytokines related to poor prognosis in patients with cancer, including IL6 and IL8, therefore suggesting that ZEB1 and ZEB2 have similar functions in terms of the regulation of production of inflammatory cytokines. Antibody array and ELISA experiments confirmed that ZEB1 controlled the production of the IL‐6 and IL‐8 proteins. The secretory proteins regulated by ZEB1 enhanced breast cancer cell proliferation and tumor growth. ZEB1 expression in breast cancer cells also affected the growth of fibroblasts in cell culture, and the accumulation of myeloid‐derived suppressor cells in tumors in vivo. These findings provide insight into the role of ZEB1 in the progression of cancer, mediated by inflammatory cytokines, along with the initiation of EMT.
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Affiliation(s)
- Akihiro Katsura
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Japan
| | - Yusuke Tamura
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Japan
| | - Satoshi Hokari
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Japan.,Department of Respiratory Medicine and Infectious Disease, Graduate School of Medical and Dental Sciences, Niigata University, Japan
| | - Mayumi Harada
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Japan.,Department of Metabolic Care and Endocrine Surgery, Graduate School of Medicine, The University of Tokyo, Japan
| | - Masato Morikawa
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Japan
| | - Tsubasa Sakurai
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Japan
| | - Kei Takahashi
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Japan
| | - Anna Mizutani
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Japan
| | - Jun Nishida
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Japan
| | - Yuichiro Yokoyama
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Japan
| | - Yasuyuki Morishita
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Japan
| | - Takashi Murakami
- Department of Microbiology, Faculty of Medicine, Saitama Medical University, Moroyama, Japan
| | - Shogo Ehata
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Japan
| | - Kohei Miyazono
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Japan
| | - Daizo Koinuma
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Japan
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9
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Abstract
Inhibitory Smads (I-Smads) have conserved carboxy-terminal MH2 domains but highly divergent amino-terminal regions when compared with receptor-regulated Smads (R-Smads) and common-partner Smads (co-Smads). Smad6 preferentially inhibits Smad signaling initiated by the bone morphogenetic protein (BMP) type I receptors ALK-3 and ALK-6, whereas Smad7 inhibits both transforming growth factor β (TGF-β)- and BMP-induced Smad signaling. I-Smads also regulate some non-Smad signaling pathways. Here, we discuss the vertebrate I-Smads, their roles as inhibitors of Smad activation and regulators of receptor stability, as scaffolds for non-Smad signaling, and their possible roles in the nucleus. We also discuss the posttranslational modification of I-Smads, including phosphorylation, ubiquitylation, acetylation, and methylation.
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Affiliation(s)
- Keiji Miyazawa
- Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan
| | - Kohei Miyazono
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
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10
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Abstract
Inhibitory Smads (I-Smads) have conserved carboxy-terminal MH2 domains but highly divergent amino-terminal regions when compared with receptor-regulated Smads (R-Smads) and common-partner Smads (co-Smads). Smad6 preferentially inhibits Smad signaling initiated by the bone morphogenetic protein (BMP) type I receptors ALK-3 and ALK-6, whereas Smad7 inhibits both transforming growth factor β (TGF-β)- and BMP-induced Smad signaling. I-Smads also regulate some non-Smad signaling pathways. Here, we discuss the vertebrate I-Smads, their roles as inhibitors of Smad activation and regulators of receptor stability, as scaffolds for non-Smad signaling, and their possible roles in the nucleus. We also discuss the posttranslational modification of I-Smads, including phosphorylation, ubiquitylation, acetylation, and methylation.
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Affiliation(s)
- Keiji Miyazawa
- Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan
| | - Kohei Miyazono
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
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11
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Sakurai T, Isogaya K, Sakai S, Morikawa M, Morishita Y, Ehata S, Miyazono K, Koinuma D. RNA-binding motif protein 47 inhibits Nrf2 activity to suppress tumor growth in lung adenocarcinoma. Oncogene 2016; 35:5000-9. [PMID: 26923328 PMCID: PMC5036161 DOI: 10.1038/onc.2016.35] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 12/22/2015] [Accepted: 01/11/2016] [Indexed: 01/27/2023]
Abstract
RNA-binding proteins provide a new layer of posttranscriptional regulation of RNA during cancer progression. We identified RNA-binding motif protein 47 (RBM47) as a target gene of transforming growth factor (TGF)-β in mammary gland epithelial cells (NMuMG cells) that have undergone the epithelial-to-mesenchymal transition. TGF-β repressed RBM47 expression in NMuMG cells and lung cancer cell lines. Expression of RBM47 correlated with good prognosis in patients with lung, breast and gastric cancer. RBM47 suppressed the expression of cell metabolism-related genes, which were the direct targets of nuclear factor erythroid 2-related factor 2 (Nrf2; also known as NFE2L2). RBM47 bound to KEAP1 and Cullin 3 mRNAs, and knockdown of RBM47 inhibited their protein expression, which led to enhanced binding of Nrf2 to target genomic regions. Knockdown of RBM47 also enhanced the expression of some Nrf2 activators, p21/CDKN1A and MafK induced by TGF-β. Both mitochondrial respiration rates and the side population cells in lung cancer cells increased in the absence of RBM47. Our findings, together with the enhanced tumor formation and metastasis of xenografted mice by knockdown of the RBM47 expression, suggested tumor-suppressive roles for RBM47 through the inhibition of Nrf2 activity.
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Affiliation(s)
- T Sakurai
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - K Isogaya
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - S Sakai
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - M Morikawa
- Ludwig Institute for Cancer Research, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Y Morishita
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - S Ehata
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - K Miyazono
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - D Koinuma
- Department of Molecular Pathology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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12
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Atg13 Is Essential for Autophagy and Cardiac Development in Mice. Mol Cell Biol 2015; 36:585-95. [PMID: 26644405 DOI: 10.1128/mcb.01005-15] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2015] [Accepted: 11/23/2015] [Indexed: 01/08/2023] Open
Abstract
Autophagy is a major intracellular degradation system by which cytoplasmic components are enclosed by autophagosomes and delivered to lysosomes. Formation of the autophagosome requires a set of autophagy-related (Atg) proteins. Among these proteins, the ULK1 complex, which is composed of ULK1 (or ULK2), FIP200, Atg13, and Atg101, acts at an initial step. Previous studies showed that ULK1 and FIP200 also function in pathways other than autophagy. However, whether Atg13 and Atg101 act similarly to ULK1 and FIP200 remains unknown. In the present study, we generated Atg13 knockout mice. Like FIP200-deficient mice, Atg13-deficient mice die in utero, which is distinct from most other types of Atg-deficient mice. Atg13-deficient embryos show growth retardation and myocardial growth defects. In cultured fibroblasts, Atg13 deficiency blocks autophagosome formation at an upstream step. In addition, sensitivity to tumor necrosis factor alpha (TNF-α)-induced apoptosis is enhanced by deletion of Atg13 or FIP200, but not by other Atg proteins, as well as by simultaneous deletion of ULK1 and ULK2. These results suggest that Atg13 has both autophagic and nonautophagic functions and that the latter are essential for cardiac development and likely shared with FIP200 but not with ULK1/2.
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13
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Wu YH, Ai X, Liu FY, Liang HF, Zhang BX, Chen XP. c-Jun N-terminal kinase inhibitor favors transforming growth factor-β to antagonize hepatitis B virus X protein-induced cell growth promotion in hepatocellular carcinoma. Mol Med Rep 2015; 13:1345-52. [PMID: 26648552 PMCID: PMC4732859 DOI: 10.3892/mmr.2015.4644] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 02/02/2015] [Indexed: 12/27/2022] Open
Abstract
Transforming growth factor (TGF)-β induces cell growth arrest in well-differentiated hepatocellular carcinoma (HCC) while hepatitis B virus X protein (HBx) minimizes the tumor suppression of TGF-β signaling in early chronic hepatitis B. However, how to reverse the oncogenic effect of HBx and sustain the tumor-suppressive action of TGF-β has yet to be investigated. The present study examined the effect of TGF-β and a c-Jun N-terminal kinase (JNK) inhibitor on cell growth in HCC cells with forced expression of HBx. It was found that HBx promoted cell growth via activation of the JNK/pSMAD3L pathway and inhibition of the transforming growth factor-beta type I receptor (TβRI)/pSMAD3C pathway. pSMAD3L/SMAD4 and pSMAD3C/SMAD4 complexes antagonized each other to regulate c-Myc expression. In the absence of HBx, TGF-β induced cell growth arrest through activation of the TβRI/pSMAD3C pathway in well-differentiated HCC cells. In the presence of HBx, TGF-β had no effect on cell growth. JNK inhibitor SP600125 significantly reversed the oncogenic action of HBx and favored TGF-β to regain the ability to inhibit the cell growth in HBx-expressing well-differentiated HCC cells. In conclusion, targeting JNK signaling favors TGF-β to block HBx-induced cell growth promotion in well-differentiated HCC cells. As an adjunct to anti-viral therapy, the combination of TGF-β and inhibition of JNK signaling is a potential therapy for HBV-infected HCC.
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Affiliation(s)
- Yan-Hui Wu
- Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
| | - Xi Ai
- Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
| | - Fu-Yao Liu
- Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
| | - Hui-Fang Liang
- Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
| | - Bi-Xiang Zhang
- Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
| | - Xiao-Ping Chen
- Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P.R. China
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14
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Wesselborg S, Stork B. Autophagy signal transduction by ATG proteins: from hierarchies to networks. Cell Mol Life Sci 2015; 72:4721-57. [PMID: 26390974 PMCID: PMC4648967 DOI: 10.1007/s00018-015-2034-8] [Citation(s) in RCA: 169] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 08/13/2015] [Accepted: 08/31/2015] [Indexed: 02/07/2023]
Abstract
Autophagy represents an intracellular degradation process which is involved in both cellular homeostasis and disease settings. In the last two decades, the molecular machinery governing this process has been characterized in detail. To date, several key factors regulating this intracellular degradation process have been identified. The so-called autophagy-related (ATG) genes and proteins are central to this process. However, several additional molecules contribute to the outcome of an autophagic response. Several review articles describing the molecular process of autophagy have been published in the recent past. In this review article we would like to add the most recent findings to this knowledge, and to give an overview of the network character of the autophagy signaling machinery.
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Affiliation(s)
- Sebastian Wesselborg
- Institute of Molecular Medicine I, Heinrich-Heine-University, Universitätsstr. 1, Building 23.12, 40225, Düsseldorf, Germany
| | - Björn Stork
- Institute of Molecular Medicine I, Heinrich-Heine-University, Universitätsstr. 1, Building 23.12, 40225, Düsseldorf, Germany.
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15
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Tsubakihara Y, Hikita A, Yamamoto S, Matsushita S, Matsushita N, Oshima Y, Miyazawa K, Imamura T. Arkadia enhances BMP signalling through ubiquitylation and degradation of Smad6. J Biochem 2015; 158:61-71. [PMID: 25762727 DOI: 10.1093/jb/mvv024] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 01/17/2015] [Indexed: 02/02/2023] Open
Abstract
Arkadia, a positive regulator of Smad-dependent signalling via the transforming growth factor-β (TGF-β) family, is an E3 ubiquitin ligase that induces ubiquitylation and proteasome-dependent degradation of TGF-β suppressors such as Smad7, c-Ski and SnoN. In this study, we examined the effects of Arkadia on bone morphogenetic protein (BMP)-induced osteoblast differentiation. Knockdown of Arkadia reduced mineralization and expression of osteoblast differentiation markers. Furthermore, we showed that Smad6, a BMP-specific inhibitory Smad, is a target of Arkadia: wild-type (WT) Arkadia, but not the C937A (CA) mutant lacking E3 ubiquitin-ligase activity, induced ubiquitylation and proteasome-dependent degradation of Smad6. Accordingly, protein levels of Smad6, Smad7 and c-Ski were elevated in MEFs from Arkadia KO mice. Finally, expression of Arkadia attenuated blockade of BMP signalling by Smad6 in a transcriptional reporter assay. These results demonstrate that Smad6 is a novel target of Arkadia, and that Arkadia positively regulates BMP signalling via degradation of Smad6, Smad7 and c-Ski/SnoN.
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Affiliation(s)
- Yutaro Tsubakihara
- Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo; Department of Gastroenterology and Metabiology, Ehime University, Shitsukawa, Toon, Ehime; Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime; and Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Atsuhiko Hikita
- Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo; Department of Gastroenterology and Metabiology, Ehime University, Shitsukawa, Toon, Ehime; Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime; and Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo; Department of Gastroenterology and Metabiology, Ehime University, Shitsukawa, Toon, Ehime; Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime; and Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo; Department of Gastroenterology and Metabiology, Ehime University, Shitsukawa, Toon, Ehime; Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime; and Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Shin Yamamoto
- Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo; Department of Gastroenterology and Metabiology, Ehime University, Shitsukawa, Toon, Ehime; Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime; and Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo; Department of Gastroenterology and Metabiology, Ehime University, Shitsukawa, Toon, Ehime; Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime; and Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Sachi Matsushita
- Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo; Department of Gastroenterology and Metabiology, Ehime University, Shitsukawa, Toon, Ehime; Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime; and Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Natsuki Matsushita
- Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo; Department of Gastroenterology and Metabiology, Ehime University, Shitsukawa, Toon, Ehime; Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime; and Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Yusuke Oshima
- Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo; Department of Gastroenterology and Metabiology, Ehime University, Shitsukawa, Toon, Ehime; Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime; and Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo; Department of Gastroenterology and Metabiology, Ehime University, Shitsukawa, Toon, Ehime; Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime; and Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo; Department of Gastroenterology and Metabiology, Ehime University, Shitsukawa, Toon, Ehime; Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime; and Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-im
| | - Keiji Miyazawa
- Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo; Department of Gastroenterology and Metabiology, Ehime University, Shitsukawa, Toon, Ehime; Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime; and Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Takeshi Imamura
- Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo; Department of Gastroenterology and Metabiology, Ehime University, Shitsukawa, Toon, Ehime; Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime; and Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo; Department of Gastroenterology and Metabiology, Ehime University, Shitsukawa, Toon, Ehime; Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime; and Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-imaging, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo; Department of Gastroenterology and Metabiology, Ehime University, Shitsukawa, Toon, Ehime; Translational Research Center, Ehime University Hospital, Shitsukawa, Toon, Ehime; and Department of Biochemistry, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime; Division of Bio-im
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16
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Zebrafish Rnf111 is encoded by multiple transcripts and is required for epiboly progression and prechordal plate development. Differentiation 2015; 89:22-30. [PMID: 25619648 DOI: 10.1016/j.diff.2014.12.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 12/04/2014] [Accepted: 12/22/2014] [Indexed: 12/12/2022]
Abstract
Arkadia (also known as RING finger 111) encodes a nuclear E3 ubiquitin ligase that targets intracellular effectors and modulators of TGFβ/Nodal-related signaling for polyubiquitination and proteasome-dependent degradation. In the mouse, loss of Arkadia results in early embryonic lethality, with defects attributed to compromised Nodal signaling. Here, we report the isolation of zebrafish arkadia/rnf111, which is represented by 5 transcript variants. arkadia/rnf111 is broadly expressed during the blastula and gastrula stages, with eventual enrichment in the anterior mesendoderm, including the prechordal plate. Morpholino knockdown experiments reveal an unexpected role for Arkadia/Rnf111 in both early blastula organization and epiboly progression. Using a splice junction morpholino, we present additional evidence that arkadia/rnf111 transcript variants containing a 3' alternative exon are specifically required for epiboly progression in the late gastrula. This result suggests that arkadia/rnf111 transcript variants encode functionally relevant protein isoforms that provide additional intracellular flexibility and regulation to the Nodal signaling pathway.
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17
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Yang Y, Cui J, Xue F, Zhang C, Mei Z, Wang Y, Bi M, Shan D, Meredith A, Li H, Xu ZQD. Pokemon (FBI-1) interacts with Smad4 to repress TGF-β-induced transcriptional responses. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1849:270-81. [PMID: 25514493 DOI: 10.1016/j.bbagrm.2014.12.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 11/20/2014] [Accepted: 12/09/2014] [Indexed: 11/16/2022]
Abstract
Pokemon, an important proto-oncoprotein, is a transcriptional repressor that belongs to the POK (POZ and Krüppel) family. Smad4, a key component of TGF-β pathway, plays an essential role in TGF-β-induced transcriptional responses. In this study, we show that Pokemon can interact directly with Smad4 both in vitro and in vivo. Overexpression of Pokemon decreases TGF-β-induced transcriptional activities, whereas knockdown of Pokemon increases these activities. Interestingly, Pokemon does not affect activation of Smad2/3, formation of Smads complex, or DNA binding activity of Smad4. TGF-β1 treatment increases the interaction between Pokemon and Smad4, and also enhances the recruitment of Pokemon to Smad4-DNA complex. In addition, we also find that Pokemon recruits HDAC1 to Smad4 complex but decreases the interaction between Smad4 and p300/CBP. Taken together, all these data suggest that Pokemon is a new partner of Smad4 and plays a negative role in TGF-β pathway.
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Affiliation(s)
- Yutao Yang
- Department of Neurobiology, Beijing Key Laboratory of Major Brain Disorders, Capital Medical University, Beijing,100069, China.
| | - Jiajun Cui
- Department of Cancer and Cell Biology, University of Cincinnati College of Medicine, Cincinnati, 45267, USA; Institute of Disease Control and Prevention, Chinese Academy of Military Medical Sciences, Beijing, 100071, China
| | - Feng Xue
- Beijing Friendship Hospital, Capital Medical University, Beijing, 100050, China
| | - Chuanfu Zhang
- Institute of Disease Control and Prevention, Chinese Academy of Military Medical Sciences, Beijing, 100071, China
| | - Zhu Mei
- Department of Neurobiology, Beijing Key Laboratory of Major Brain Disorders, Capital Medical University, Beijing,100069, China
| | - Yue Wang
- Beijing Chao-Yang Hospital, Capital Medical University, Beijing, 100020, China
| | - Mingjun Bi
- Department of Cancer and Cell Biology, University of Cincinnati College of Medicine, Cincinnati, 45267, USA
| | - Dapeng Shan
- Third Institute of Oceanography, State Oceanic Administration, Xiamen, 361005, China
| | - Alex Meredith
- Department of Cancer and Cell Biology, University of Cincinnati College of Medicine, Cincinnati, 45267, USA
| | - Hui Li
- Department of Molecular and Biomedical Pharmacology, University of Kentucky College of Medicine, Lexington KY, 40536, USA
| | - Zhi-Qing David Xu
- Department of Neurobiology, Beijing Key Laboratory of Major Brain Disorders, Capital Medical University, Beijing,100069, China.
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18
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A Smad3 and TTF-1/NKX2-1 complex regulates Smad4-independent gene expression. Cell Res 2014; 24:994-1008. [PMID: 25060702 PMCID: PMC4123303 DOI: 10.1038/cr.2014.97] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 04/06/2014] [Accepted: 05/04/2014] [Indexed: 02/08/2023] Open
Abstract
Thyroid transcription factor-1 (TTF-1, also known as NKX2-1) is a tissue-specific transcription factor in lung epithelial cells. Although TTF-1 inhibits the epithelial-to-mesenchymal transition induced by transforming growth factor-β (TGF-β) in lung adenocarcinoma cells, the mechanism through which TTF-1 inhibits the functions of TGF-β is unknown. Here we show that TTF-1 disrupts the nuclear Smad3-Smad4 complex without affecting the nuclear localization of phospho-Smad3. Genome-wide analysis by chromatin immunoprecipitation followed by sequencing revealed that TTF-1 colocalizes with Smad3 on chromatin and alters Smad3-binding patterns throughout the genome, while TTF-1 generally inhibits Smad4 binding to chromatin. Moreover, Smad3 binds to chromatin together with TTF-1, but not with Smad4, at some Smad3-binding regions when TGF-β signaling is absent, and knockdown of Smad4 expression does not attenuate Smad3 binding in these regions. Thus, TTF-1 may compete with Smad4 for interaction with Smad3, and in the presence of TTF-1, Smad3 regulates the transcription of certain genes independently of Smad4. These findings provide a new model of regulation of TGF-β-Smad signaling by TTF-1.
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19
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Yeh ML, Gonda Y, Mommersteeg MTM, Barber M, Ypsilanti AR, Hanashima C, Parnavelas JG, Andrews WD. Robo1 modulates proliferation and neurogenesis in the developing neocortex. J Neurosci 2014; 34:5717-31. [PMID: 24741061 PMCID: PMC3988420 DOI: 10.1523/jneurosci.4256-13.2014] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Revised: 02/19/2014] [Accepted: 03/19/2014] [Indexed: 12/11/2022] Open
Abstract
The elaborate cytoarchitecture of the mammalian neocortex requires the timely production of its constituent pyramidal neurons and interneurons and their disposition in appropriate layers. Numerous chemotropic factors present in the forebrain throughout cortical development play important roles in the orchestration of these events. The Roundabout (Robo) family of receptors and their ligands, the Slit proteins, are expressed in the developing forebrain, and are known to play important roles in the generation and migration of cortical interneurons. However, few studies have investigated their function(s) in the development of pyramidal cells. Here, we observed expression of Robo1 and Slit genes (Slit1, Slit2) in cells lining the telencephalic ventricles, and found significant increases in progenitor cells (basal and apical) at embryonic day (E)12.5 and E14.5 in the developing cortex of Robo1(-/-), Slit1(-/-), and Slit1(-/-)/Slit2(-/-), but not in mice lacking the other Robo or Slit genes. Using layer-specific markers, we found that both early- and late-born pyramidal neuron populations were significantly increased in the cortices of Robo1(-/-) mice at the end of corticogenesis (E18.5). The excess number of cortical pyramidal neurons generated prenatally appears to die in early postnatal life. The observed increase in pyramidal neurons was due to prolonged proliferative activity of their progenitors and not due to changes in cell cycle events. This finding, confirmed by in utero electroporation with Robo1 short hairpin RNA (shRNA) or control constructs into progenitors along the ventricular zone as well as in dissociated cortical cell cultures, points to a novel role for Robo1 in regulating the proliferation and generation of pyramidal neurons.
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Affiliation(s)
- Mason L. Yeh
- Department of Cell and Developmental Biology, University College London, London, United Kingdom WC1E 6DE
| | - Yuko Gonda
- Laboratory for Neocortical Development, RIKEN Center for Developmental Biology, Kobe 650-0047, Japan
| | - Mathilda T. M. Mommersteeg
- Department of Cell and Developmental Biology, University College London, London, United Kingdom WC1E 6DE
| | - Melissa Barber
- Institut Jacques-Monod, Université Paris Diderot/CNRS, 75201 Paris, France, and
| | | | - Carina Hanashima
- Laboratory for Neocortical Development, RIKEN Center for Developmental Biology, Kobe 650-0047, Japan
| | - John G. Parnavelas
- Department of Cell and Developmental Biology, University College London, London, United Kingdom WC1E 6DE
| | - William D. Andrews
- Department of Cell and Developmental Biology, University College London, London, United Kingdom WC1E 6DE
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20
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Imamura T, Oshima Y, Hikita A. Regulation of TGF-β family signalling by ubiquitination and deubiquitination. J Biochem 2013; 154:481-9. [PMID: 24165200 DOI: 10.1093/jb/mvt097] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Members of the transforming growth factor-β (TGF-β) family, including TGF-βs, activin and bone morphogenetic proteins (BMPs), are multifunctional proteins that regulate a wide variety of cellular responses, such as proliferation, differentiation, migration and apoptosis. TGF-β family signalling is mainly mediated by membranous serine/threonine kinase receptors and intracellular Smad proteins. This signalling is tightly regulated by various post-translational modifications including ubiquitination. Several E3 ubiquitin ligases play a crucial role in the recognition and ubiquitin-dependent degradation of TGF-β family receptors, Smad proteins and their interacted proteins to regulate positively and negatively TGF-β family signalling. In contrast, non-degradative ubiquitin modifications also regulate TGF-β family signalling. Recently, in addition to protein ubiquitination, deubiquitination by deubiquitinating enzymes has been reported to control TGF-β family signalling pathways. Interestingly, more recent studies suggest that TGF-β signalling is not only regulated via ubiquitination and/or deubiquitination, but also it relies on ubiquitination for its effect on other pathways. Thus, ubiquitin modifications play key roles in TGF-β family signal transduction and cross-talk between TGF-β family signalling and other signalling pathways. Here, we review the current understandings of the positive and negative regulatory mechanisms by ubiquitin modifications that control TGF-β family signalling.
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Affiliation(s)
- Takeshi Imamura
- Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine; Division of Bio-imaging, Proteo-Science Center, Ehime University; Translational Research Center, Ehime University Hospital; and Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Shitsukawa, Toon, Ehime 791-0295, Japan
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Al-Salihi MA, Herhaus L, Sapkota GP. Regulation of the transforming growth factor β pathway by reversible ubiquitylation. Open Biol 2013; 2:120082. [PMID: 22724073 PMCID: PMC3376735 DOI: 10.1098/rsob.120082] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Accepted: 04/25/2012] [Indexed: 12/20/2022] Open
Abstract
The transforming growth factor β (TGFβ) signalling pathway plays a central role during embryonic development and in adult tissue homeostasis. It regulates gene transcription through a signalling cascade from cell surface receptors to intracellular SMAD transcription factors and their nuclear cofactors. The extent, duration and potency of signalling in response to TGFβ cytokines are intricately regulated by complex biochemical processes. The corruption of these regulatory processes results in aberrant TGFβ signalling and leads to numerous human diseases, including cancer. Reversible ubiquitylation of pathway components is a key regulatory process that plays a critical role in ensuring a balanced response to TGFβ signals. Many studies have investigated the mechanisms by which various E3 ubiquitin ligases regulate the turnover and activity of TGFβ pathway components by ubiquitylation. Moreover, recent studies have shed new light into their regulation by deubiquitylating enzymes. In this report, we provide an overview of current understanding of the regulation of TGFβ signalling by E3 ubiquitin ligases and deubiquitylases.
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Affiliation(s)
- Mazin A Al-Salihi
- Medical Research Council-Protein Phosphorylation Unit, Sir James Black Centre, University of Dundee, Dow Street, Dundee DD1 5EH, UK
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Gui T, Sun Y, Gai Z, Shimokado A, Muragaki Y, Zhou G. The loss of Trps1 suppresses ureteric bud branching because of the activation of TGF-β signaling. Dev Biol 2013; 377:415-27. [DOI: 10.1016/j.ydbio.2013.03.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 03/14/2013] [Accepted: 03/18/2013] [Indexed: 11/27/2022]
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Kelly CE, Thymiakou E, Dixon JE, Tanaka S, Godwin J, Episkopou V. Rnf165/Ark2C enhances BMP-Smad signaling to mediate motor axon extension. PLoS Biol 2013; 11:e1001538. [PMID: 23610558 PMCID: PMC3627648 DOI: 10.1371/journal.pbio.1001538] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 03/07/2013] [Indexed: 12/21/2022] Open
Abstract
Little is known about extrinsic signals required for the advancement of motor neuron (MN) axons, which extend over long distances in the periphery to form precise connections with target muscles. Here we present that Rnf165 (Arkadia-like; Arkadia2; Ark2C) is expressed specifically in the nervous system and that its loss in mice causes motor innervation defects that originate during development and lead to wasting and death before weaning. The defects range from severe reduction of motor axon extension as observed in the dorsal forelimb to shortening of presynaptic branches of the phrenic nerve, as observed in the diaphragm. Molecular functional analysis showed that in the context of the spinal cord Ark2C enhances transcriptional responses of the Smad1/5/8 effectors, which are activated (phosphorylated) downstream of Bone Morphogenetic Protein (BMP) signals. Consistent with Ark2C-modulated BMP signaling influencing motor axons, motor pools in the spinal cord were found to harbor phosphorylated Smad1/5/8 (pSmad) and treatment of primary MN with BMP inhibitor diminished axon length. In addition, genetic reduction of BMP-Smad signaling in Ark2C (+/-) mice caused the emergence of Ark2C (-/-) -like dorsal forelimb innervation deficits confirming that enhancement of BMP-Smad responses by Ark2C mediates efficient innervation. Together the above data reveal an involvement of BMP-Smad signaling in motor axon advancement.
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Affiliation(s)
- Claire E. Kelly
- Division of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Efstathia Thymiakou
- Division of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - James E. Dixon
- Division of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Shinya Tanaka
- Division of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Jonathan Godwin
- Division of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Vasso Episkopou
- Division of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
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Ma T, Chen Y, Zhang F, Yang CY, Wang S, Yu X. RNF111-dependent neddylation activates DNA damage-induced ubiquitination. Mol Cell 2013; 49:897-907. [PMID: 23394999 DOI: 10.1016/j.molcel.2013.01.006] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Revised: 09/24/2012] [Accepted: 01/04/2013] [Indexed: 11/30/2022]
Abstract
Ubiquitin-like proteins have been shown to be covalently conjugated to targets. However, the functions of these ubiquitin-like proteins are largely unknown. Here, we have screened most known ubiquitin-like proteins after DNA damage and found that NEDD8 is involved in the DNA damage response. Following various DNA damage stimuli, NEDD8 accumulated at DNA damage sites; this accumulation was dependent on an E2 enzyme (UBE2M) and an E3 ubiquitin ligase (RNF111). We further found that histone H4 was polyneddylated in response to DNA damage, and NEDD8 was conjugated to the N-terminal lysine residues of H4. Interestingly, the DNA damage-induced polyneddylation chain could be recognized by the MIU (motif interacting with ubiquitin) domain of RNF168. Loss of DNA damage-induced neddylation negatively regulated DNA damage-induced foci formation of RNF168 and its downstream functional partners, such as 53BP1 and BRCA1, thus affecting the normal DNA damage repair process.
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Affiliation(s)
- Teng Ma
- Division of Molecular Medicine and Genetics, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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Wong PM, Puente C, Ganley IG, Jiang X. The ULK1 complex: sensing nutrient signals for autophagy activation. Autophagy 2013; 9:124-37. [PMID: 23295650 PMCID: PMC3552878 DOI: 10.4161/auto.23323] [Citation(s) in RCA: 369] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The Atg1/ULK1 complex plays a central role in starvation-induced autophagy, integrating signals from upstream sensors such as MTOR and AMPK and transducing them to the downstream autophagy pathway. Much progress has been made in the last few years in understanding the mechanisms by which the complex is regulated through protein-protein interactions and post-translational modifications, providing insights into how the cell modulates autophagy, particularly in response to nutrient status. However, how the ULK1 complex transduces upstream signals to the downstream central autophagy pathway is still unclear. Although the protein kinase activity of ULK1 is required for its autophagic function, its protein substrate(s) responsible for autophagy activation has not been identified. Furthermore, examples of potential ULK1-independent autophagy have emerged, indicating that under certain specific contexts, the ULK1 complex might be dispensable for autophagy activation. This raises the question of how the autophagic machinery is activated independent of the ULK1 complex and what are the biological functions of such noncanonical autophagy pathways.
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Affiliation(s)
- Pui-Mun Wong
- Cell Biology Program; Memorial Sloan-Kettering Cancer Center; New York, NY USA
| | - Cindy Puente
- Cell Biology Program; Memorial Sloan-Kettering Cancer Center; New York, NY USA
| | - Ian G. Ganley
- MRC Protein Phosphorylation Unit; University of Dundee; Dundee, Scotland UK
| | - Xuejun Jiang
- Cell Biology Program; Memorial Sloan-Kettering Cancer Center; New York, NY USA
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Choi JD, Ryu M, Ae Park M, Jeong G, Lee JS. FIP200 inhibits β-catenin-mediated transcription by promoting APC-independent β-catenin ubiquitination. Oncogene 2012; 32:2421-32. [PMID: 22751121 DOI: 10.1038/onc.2012.262] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Focal adhesion kinase-family-interacting protein of 200 kDa (FIP200) has been shown to regulate multiple cellular functions, including cell adhesion, autophagy, development and proliferation. Furthermore, FIP200 is considered to have tumor-suppressive activity, which may be correlated with its inactivation in human breast cancers, in addition to its role as an important signal transduction node. Herein, we report that FIP200 interacts with the oncoprotein β-catenin. Moreover, FIP200 promotes destabilization of wild-type β-catenin, but not a cancer-causing form of β-catenin, and as a result represses the β-catenin-mediated transcription. FIP200-induced degradation of β-catenin is independent of adenomatous polyposis coli (APC) of the well-established β-catenin destruction complex (glycogen synthase kinase-3β/axin/APC), in a component of β-catenin E3 ubiquitin ligase, β-TrCP-dependent manner. Thus, the APC-independent β-catenin degradation by FIP200 suggests a role for FIP200 in tumor suppression in the presence of APC dysfunction. These findings reveal a new and important function of FIP200 in regulation of the Wnt/β-catenin pathway.
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Affiliation(s)
- J D Choi
- Department of Molecular Science and Technology, College of Natural Sciences, Ajou University, Suwon, Korea
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Abstract
The transforming growth factor β (TGFβ) superfamily of signal transduction molecules plays crucial roles in the regulation of cell behavior. TGFβ regulates gene transcription through Smad proteins and signals via non-Smad pathways. The TGFβ pathway is strictly regulated, and perturbations lead to tumorigenesis. Several pathway components are known to be targeted for proteasomal degradation via ubiquitination by E3 ligases. Smurfs are well known negative regulators of TGFβ, which function as E3 ligases recruited by adaptors such as I-Smads. TGFβ signaling can also be enhanced by E3 ligases, such as Arkadia, that target repressors for degradation. It is becoming clear that E3 ligases often target multiple pathways, thereby acting as mediators of signaling cross-talk. Regulation via ubiquitination involves a complex network of E3 ligases, adaptor proteins, and deubiquitinating enzymes (DUBs), the last-mentioned acting by removing ubiquitin from its targets. Interestingly, also non-degradative ubiquitin modifications are known to play important roles in TGFβ signaling. Ubiquitin modifications thus play a key role in TGFβ signal transduction, and in this review we provide an overview of known players, focusing on recent advances.
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Affiliation(s)
- Miriam De Boeck
- Department of Molecular Cell Biology and Centre for Biomedical Genetics, Leiden University Medical Center, Leiden, The Netherlands.
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Structure of a dominant-negative helix-loop-helix transcriptional regulator suggests mechanisms of autoinhibition. EMBO J 2012; 31:2541-52. [PMID: 22453338 DOI: 10.1038/emboj.2012.77] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2011] [Accepted: 03/06/2012] [Indexed: 01/28/2023] Open
Abstract
Helix-loop-helix (HLH) family transcription factors regulate numerous developmental and homeostatic processes. Dominant-negative HLH (dnHLH) proteins lack DNA-binding ability and capture basic HLH (bHLH) transcription factors to inhibit cellular differentiation and enhance cell proliferation and motility, thus participating in patho-physiological processes. We report the first structure of a free-standing human dnHLH protein, HHM (Human homologue of murine maternal Id-like molecule). HHM adopts a V-shaped conformation, with N-terminal and C-terminal five-helix bundles connected by the HLH region. In striking contrast to the common HLH, the HLH region in HHM is extended, with its hydrophobic dimerization interfaces embedded in the N- and C-terminal helix bundles. Biochemical and physicochemical analyses revealed that HHM exists in slow equilibrium between this V-shaped form and the partially unfolded, relaxed form. The latter form is readily available for interactions with its target bHLH transcription factors. Mutations disrupting the interactions in the V-shaped form compromised the target transcription factor specificity and accelerated myogenic cell differentiation. Therefore, the V-shaped form of HHM may represent an autoinhibited state, and the dynamic conformational equilibrium may control the target specificity.
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