251
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Role of mTOR in Glucose and Lipid Metabolism. Int J Mol Sci 2018; 19:ijms19072043. [PMID: 30011848 PMCID: PMC6073766 DOI: 10.3390/ijms19072043] [Citation(s) in RCA: 157] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 07/10/2018] [Accepted: 07/11/2018] [Indexed: 02/06/2023] Open
Abstract
The mammalian target of rapamycin, mTOR is the master regulator of a cell’s growth and metabolic state in response to nutrients, growth factors and many extracellular cues. Its dysregulation leads to a number of metabolic pathological conditions, including obesity and type 2 diabetes. Here, we review recent findings on the role of mTOR in major metabolic organs, such as adipose tissues, liver, muscle, pancreas and brain. And their potentials as the mTOR related pharmacological targets will be also discussed.
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252
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Levin A, Minis A, Lalazar G, Rodriguez J, Steller H. PSMD5 Inactivation Promotes 26S Proteasome Assembly during Colorectal Tumor Progression. Cancer Res 2018; 78:3458-3468. [PMID: 29716915 PMCID: PMC6030489 DOI: 10.1158/0008-5472.can-17-2296] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 12/29/2017] [Accepted: 04/18/2018] [Indexed: 01/09/2023]
Abstract
Protein degradation by the ubiquitin-proteasome system (UPS) is central to protein homeostasis and cell survival. The active 26S proteasome is a large protease complex consisting of a catalytic 20S subunit and 19S regulatory particles. Cancer cells are exposed to considerable protein overload due to high metabolic rates, reprogrammed energy metabolism, and aneuploidy. Here we report a mechanism that facilitates the assembly of active 26S proteasomes in malignant cells. Upon tumorigenic transformation of the gut epithelium, 26S proteasome assembly was significantly enhanced, but levels of individual subunits were not changed. This enhanced assembly of 26S proteasomes increased further with tumor progression and was observed specifically in transformed cells, but not in other rapidly dividing cells. Moreover, expression of PSMD5, an inhibitor of proteasome assembly, was reduced in intestinal tumors and silenced with tumor progression. Reexpression of PSMD5 in tumor cells caused decreased 26S assembly and accumulation of polyubiquitinated proteins. These results suggest that inhibition of cancer-associated proteasome assembly may provide a novel therapeutic strategy to selectively kill cancer cells.Significance: Enhanced cancer-associated proteasome assembly is a major stress response that allows tumors to adapt to and to withstand protein overload.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/78/13/3458/F1.large.jpg Cancer Res; 78(13); 3458-68. ©2018 AACR.
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Affiliation(s)
- Avi Levin
- Strang Laboratory of Apoptosis and Cancer Biology, The Rockefeller University, New York, New York.
- Division of Gastroenterology, University of Iowa, Iowa City, Iowa
| | - Adi Minis
- Strang Laboratory of Apoptosis and Cancer Biology, The Rockefeller University, New York, New York
| | - Gadi Lalazar
- Laboratory of Cellular Biophysics, The Rockefeller University, New York, New York
| | - Jose Rodriguez
- Strang Laboratory of Apoptosis and Cancer Biology, The Rockefeller University, New York, New York
| | - Hermann Steller
- Strang Laboratory of Apoptosis and Cancer Biology, The Rockefeller University, New York, New York.
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253
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Iezaki T, Horie T, Fukasawa K, Kitabatake M, Nakamura Y, Park G, Onishi Y, Ozaki K, Kanayama T, Hiraiwa M, Kitaguchi Y, Kaneda K, Manabe T, Ishigaki Y, Ohno M, Hinoi E. Translational Control of Sox9 RNA by mTORC1 Contributes to Skeletogenesis. Stem Cell Reports 2018; 11:228-241. [PMID: 30008325 PMCID: PMC6117477 DOI: 10.1016/j.stemcr.2018.05.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 05/31/2018] [Accepted: 05/31/2018] [Indexed: 11/18/2022] Open
Abstract
The mechanistic/mammalian target of rapamycin complex 1 (mTORC1) regulates cellular function in various cell types. Although the role of mTORC1 in skeletogenesis has been investigated previously, here we show a critical role of mTORC1/4E-BPs/SOX9 axis in regulating skeletogenesis through its expression in undifferentiated mesenchymal cells. Inactivation of Raptor, a component of mTORC1, in limb buds before mesenchymal condensations resulted in a marked loss of both cartilage and bone. Mechanistically, we demonstrated that mTORC1 selectively controls the RNA translation of Sox9, which harbors a 5′ terminal oligopyrimidine tract motif, via inhibition of the 4E-BPs. Indeed, introduction of Sox9 or a knockdown of 4E-BP1/2 in undifferentiated mesenchymal cells markedly rescued the deficiency of the condensation observed in Raptor-deficient mice. Furthermore, introduction of the Sox9 transgene rescued phenotypes of deficient skeletal growth in Raptor-deficient mice. These findings highlight a critical role of mTORC1 in mammalian skeletogenesis, at least in part, through translational control of Sox9 RNA. mTORC1 controls skeletogenesis both in skeletogenic progenitors and in chondrocytes mTORC1/4E-BPs cascade regulates the translation of Sox9 RNA SOX9 is a critical mediator in the control of skeletogenesis by mTORC1 in vivo
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Affiliation(s)
- Takashi Iezaki
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan; Venture Business Laboratory, Organization of Frontier Science and Innovation, Kanazawa University, Kanazawa, Ishikawa 920-1192, Japan
| | - Tetsuhiro Horie
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Kazuya Fukasawa
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Makoto Kitabatake
- Institute for Virus Research, Kyoto University, Kyoto 606-8507, Japan
| | - Yuka Nakamura
- Medical Research Institute, Kanazawa Medical University, Kahoku, Ishikawa 920-0293, Japan
| | - Gyujin Park
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Yuki Onishi
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Kakeru Ozaki
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Takashi Kanayama
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Manami Hiraiwa
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Yuka Kitaguchi
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Katsuyuki Kaneda
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
| | - Takayuki Manabe
- Department of Neuroanatomy and Neuropharmacology, Faculty of Nursing, Chukyogakuin University, Mizunami, Gifu 509-6192, Japan
| | - Yasuhito Ishigaki
- Medical Research Institute, Kanazawa Medical University, Kahoku, Ishikawa 920-0293, Japan
| | - Mutsuhito Ohno
- Institute for Virus Research, Kyoto University, Kyoto 606-8507, Japan
| | - Eiichi Hinoi
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan.
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254
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Ma Y, Vassetzky Y, Dokudovskaya S. mTORC1 pathway in DNA damage response. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:1293-1311. [PMID: 29936127 DOI: 10.1016/j.bbamcr.2018.06.011] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 06/18/2018] [Accepted: 06/19/2018] [Indexed: 12/27/2022]
Abstract
Living organisms have evolved various mechanisms to control their metabolism and response to various stresses, allowing them to survive and grow in different environments. In eukaryotes, the highly conserved mechanistic target of rapamycin (mTOR) signaling pathway integrates both intracellular and extracellular signals and serves as a central regulator of cellular metabolism, proliferation and survival. A growing body of evidence indicates that mTOR signaling is closely related to another cellular protection mechanism, the DNA damage response (DDR). Many factors important for the DDR are also involved in the mTOR pathway. In this review, we discuss how these two pathways communicate to ensure an efficient protection of the cell against metabolic and genotoxic stresses. We also describe how anticancer therapies benefit from simultaneous targeting of the DDR and mTOR pathways.
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Affiliation(s)
- Yinxing Ma
- CNRS UMR 8126, Université Paris-Sud 11, Institut Gustave Roussy, 114, rue Edouard Vaillant, 94805 Villejuif, France
| | - Yegor Vassetzky
- CNRS UMR 8126, Université Paris-Sud 11, Institut Gustave Roussy, 114, rue Edouard Vaillant, 94805 Villejuif, France
| | - Svetlana Dokudovskaya
- CNRS UMR 8126, Université Paris-Sud 11, Institut Gustave Roussy, 114, rue Edouard Vaillant, 94805 Villejuif, France.
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255
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Maharjan Y, Lee JN, Kwak S, Lim H, Dutta RK, Liu ZQ, So HS, Park R. Autophagy alteration prevents primary cilium disassembly in RPE1 cells. Biochem Biophys Res Commun 2018; 500:242-248. [DOI: 10.1016/j.bbrc.2018.04.051] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Accepted: 04/07/2018] [Indexed: 01/14/2023]
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256
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Ato S, Makanae Y, Kido K, Sase K, Yoshii N, Fujita S. The effect of different acute muscle contraction regimens on the expression of muscle proteolytic signaling proteins and genes. Physiol Rep 2018; 5:5/15/e13364. [PMID: 28778992 PMCID: PMC5555890 DOI: 10.14814/phy2.13364] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 06/27/2017] [Accepted: 06/28/2017] [Indexed: 01/07/2023] Open
Abstract
Previous studies have reported that different modes of muscle contraction (i.e., eccentric or concentric contraction) with similar contraction times can affect muscle proteolytic responses. However, the effect of different contraction modes on muscle proteolytic response under the same force-time integral (FTI: contraction force × time) has not been investigated. The purpose of this study was to investigate the effect of different contraction modes, with the same FTI, on acute proteolytic signaling responses. Eleven-week-old male Sprague-Dawley rats were randomly assigned to eccentric (EC), concentric (CC), or isometric contraction (IC) groups. Different modes of muscle contraction were performed on the right gastrocnemius muscle using electrical stimulation, with the left muscle acting as a control. In order to apply an equivalent FTI, the number of stimulation sets was modified between the groups. Muscle samples were taken immediately and three hours after exercise. Phosphorylation of FoxO3a at Ser253 was significantly increased immediately after exercise compared to controls irrespective of contraction mode. The mRNA levels of the ubiquitin ligases, MuRF1, and MAFbx mRNA were unchanged by contraction mode or time. Phosphorylation of ULK1 at Ser317 (positive regulatory site) and Ser757 (negative regulatory site) was significantly increased compared to controls, immediately or 3 h after exercise, in all contraction modes. The autophagy markers (LC3B-II/I ratio and p62 expression) were unchanged, regardless of contraction mode. These data suggest that differences in contraction mode during resistance exercise with a constant FTI, are not factors in regulating proteolytic signaling in the early phase of skeletal muscle contraction.
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Affiliation(s)
- Satoru Ato
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Yuhei Makanae
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Kohei Kido
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Kohei Sase
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Naomi Yoshii
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Satoshi Fujita
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
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257
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Abstract
The mechanistic target of rapamycin (mTOR) is an evolutionarily conserved serine/threonine kinase that senses and integrates environmental information into cellular regulation and homeostasis. Accumulating evidence has suggested a master role of mTOR signalling in many fundamental aspects of cell biology and organismal development. mTOR deregulation is implicated in a broad range of pathological conditions, including diabetes, cancer, neurodegenerative diseases, myopathies, inflammatory, infectious, and autoimmune conditions. Here, we review recent advances in our knowledge of mTOR signalling in mammalian physiology. We also discuss the impact of mTOR alteration in human diseases and how targeting mTOR function can treat human diseases.
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Affiliation(s)
- Yassine El Hiani
- a Department of Physiology and Biophysics, Dalhousie University, PO Box 15000, Halifax, NS B3H 4R2, Canada
| | - Emmanuel Eroume-A Egom
- b Jewish General Hospital and Lady Davis Institute for Medical Research, Montreal, QC H3T 1E2, Canada
| | - Xian-Ping Dong
- a Department of Physiology and Biophysics, Dalhousie University, PO Box 15000, Halifax, NS B3H 4R2, Canada
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258
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Miettinen TP, Peltier J, Härtlova A, Gierliński M, Jansen VM, Trost M, Björklund M. Thermal proteome profiling of breast cancer cells reveals proteasomal activation by CDK4/6 inhibitor palbociclib. EMBO J 2018; 37:e98359. [PMID: 29669860 PMCID: PMC5978322 DOI: 10.15252/embj.201798359] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 03/02/2018] [Accepted: 03/09/2018] [Indexed: 11/24/2022] Open
Abstract
Palbociclib is a CDK4/6 inhibitor approved for metastatic estrogen receptor-positive breast cancer. In addition to G1 cell cycle arrest, palbociclib treatment results in cell senescence, a phenotype that is not readily explained by CDK4/6 inhibition. In order to identify a molecular mechanism responsible for palbociclib-induced senescence, we performed thermal proteome profiling of MCF7 breast cancer cells. In addition to affecting known CDK4/6 targets, palbociclib induces a thermal stabilization of the 20S proteasome, despite not directly binding to it. We further show that palbociclib treatment increases proteasome activity independently of the ubiquitin pathway. This leads to cellular senescence, which can be counteracted by proteasome inhibitors. Palbociclib-induced proteasome activation and senescence is mediated by reduced proteasomal association of ECM29. Loss of ECM29 activates the proteasome, blocks cell proliferation, and induces a senescence-like phenotype. Finally, we find that ECM29 mRNA levels are predictive of relapse-free survival in breast cancer patients treated with endocrine therapy. In conclusion, thermal proteome profiling identifies the proteasome and ECM29 protein as mediators of palbociclib activity in breast cancer cells.
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Affiliation(s)
- Teemu P Miettinen
- Division of Cell and Developmental Biology, University of Dundee, Dundee, UK
- MRC Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Dundee, UK
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Julien Peltier
- MRC Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Dundee, UK
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, UK
| | - Anetta Härtlova
- MRC Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Dundee, UK
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, UK
| | - Marek Gierliński
- Division of Computational Biology, University of Dundee, Dundee, UK
| | - Valerie M Jansen
- Division of Hematology-Oncology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Matthias Trost
- MRC Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Dundee, UK
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, UK
| | - Mikael Björklund
- Division of Cell and Developmental Biology, University of Dundee, Dundee, UK
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259
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Luhr M, Sætre F, Engedal N. The Long-lived Protein Degradation Assay: an Efficient Method for Quantitative Determination of the Autophagic Flux of Endogenous Proteins in Adherent Cell Lines. Bio Protoc 2018; 8:e2836. [PMID: 34286043 DOI: 10.21769/bioprotoc.2836] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 04/17/2018] [Accepted: 04/20/2018] [Indexed: 12/25/2022] Open
Abstract
Autophagy is a key player in the maintenance of cellular homeostasis in eukaryotes, and numerous diseases, including cancer and neurodegenerative disorders, are associated with alterations in autophagy. The interest for studying autophagy has grown intensely in the last two decades, and so has the arsenal of methods utilised to study this highly dynamic and complex process. Changes in the expression and/or localisation of autophagy-related proteins are frequently assessed by Western blot and various microscopy techniques. Such analyses may be indicative of alterations in autophagy-related processes and informative about the specific marker being investigated. However, since these proteins are part of the autophagic machinery, and not autophagic cargo, they cannot be used to draw conclusions regarding autophagic cargo flux. Here, we provide a protocol to quantitatively assess bulk autophagic flux by employing the long-lived protein degradation assay. Our procedure, which traces the degradation of 14C valine-labelled proteins, is simple and quick, allows for processing of a relatively large number of samples in parallel, and can in principle be used with any adherent cell line. Most importantly, it enables quantitative measurements of endogenous cargo flux through the autophagic pathway. As such, it is one of the gold standards for studying autophagic activity.
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Affiliation(s)
- Morten Luhr
- The Autophagy Team, Centre for Molecular Medicine Norway (NCMM), Nordic EMBL Partnership, University of Oslo, Oslo, Norway
| | - Frank Sætre
- The Autophagy Team, Centre for Molecular Medicine Norway (NCMM), Nordic EMBL Partnership, University of Oslo, Oslo, Norway
| | - Nikolai Engedal
- The Autophagy Team, Centre for Molecular Medicine Norway (NCMM), Nordic EMBL Partnership, University of Oslo, Oslo, Norway
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260
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Lim JA, Sun B, Puertollano R, Raben N. Therapeutic Benefit of Autophagy Modulation in Pompe Disease. Mol Ther 2018; 26:1783-1796. [PMID: 29804932 DOI: 10.1016/j.ymthe.2018.04.025] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 04/25/2018] [Accepted: 04/30/2018] [Indexed: 12/11/2022] Open
Abstract
The complexity of the pathogenic cascade in lysosomal storage disorders suggests that combination therapy will be needed to target various aspects of pathogenesis. The standard of care for Pompe disease (glycogen storage disease type II), a deficiency of lysosomal acid alpha glucosidase, is enzyme replacement therapy (ERT). Many patients have poor outcomes due to limited efficacy of the drug in clearing muscle glycogen stores. The resistance to therapy is linked to massive autophagic buildup in the diseased muscle. We have explored two strategies to address the problem. Genetic suppression of autophagy in muscle of knockout mice resulted in the removal of autophagic buildup, increase in muscle force, decrease in glycogen level, and near-complete clearance of lysosomal glycogen following ERT. However, this approach leads to accumulation of ubiquitinated proteins, oxidative stress, and exacerbation of muscle atrophy. Another approach involves AAV-mediated TSC knockdown in knockout muscle leading to upregulation of mTOR, inhibition of autophagy, reversal of atrophy, and efficient cellular clearance on ERT. Importantly, this approach reveals the possibility of reversing already established autophagic buildup, rather than preventing its development.
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Affiliation(s)
- Jeong-A Lim
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD, USA; Division of Medical Genetics, Department of Pediatrics, Duke University School of Medicine, Durham, NC, USA
| | - Baodong Sun
- Division of Medical Genetics, Department of Pediatrics, Duke University School of Medicine, Durham, NC, USA
| | - Rosa Puertollano
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD, USA.
| | - Nina Raben
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD, USA.
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261
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Xu T, Yang X, Wu C, Qiu J, Fang Q, Wang L, Yu S, Sun H. Pyrroloquinoline quinone attenuates cachexia-induced muscle atrophy via suppression of reactive oxygen species. J Thorac Dis 2018; 10:2752-2759. [PMID: 29997937 PMCID: PMC6006103 DOI: 10.21037/jtd.2018.04.112] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 04/11/2018] [Indexed: 12/23/2022]
Abstract
BACKGROUND Cachexia, a wasting syndrome, is most commonly observed in individuals with advanced cancer including lung cancer, esophageal cancer, liver cancer, etc. The characteristic sign of cachexia is muscle atrophy. To date, effective countermeasures have been still deficiency to alleviate muscle atrophy. Reactive oxygen species (ROS) are important regulators of muscle atrophy. Therefore, the effects of a naturally antioxidant, pyrroloquinoline quinone (PQQ), were explored on muscle atrophy induced by cachexia in the present study. METHODS Tumor necrosis factor-α (TNF-α) induced C2C12 myotubes atrophy model was constructed. The atrophied C2C12 myotubes were dealt with the presence or absence of N-acetyl-L-cysteine (NAC, an antioxidant for ROS abolition) (5 mM) or PQQ (80 µM) for 24 hours. ROS content was determined by dichlorodihydrofluorescein diacetate (DCFH-DA) staining. The diameter of myotubes was analyzed by myosin heavy chain (MHC) staining. The protein levels of MHC, muscle atrophy F-box (MAFbx) and muscle RING finger-1 (MuRF-1) in each group were observed by Western blotting. RESULTS First, ROS generation was enhanced in C2C12 myotubes treated with TNF-α. NAC treatments significantly avoided the reduction in the diameter of C2C12 myotubes, and concomitantly increased MHC levels, and decreased ROS contents, MuRF1 and MAFbx levels. These data suggested that the increased ROS induced by TNF-α might play a central role in muscle wasting. PQQ (a naturally occurring antioxidant) administration inhibited C2C12 myotubes atrophy induced by TNF-α, as evidenced by the increase of the diameter of C2C12 myotubes, together with increased MHC levels and decreased ROS, MAFbx and MuRF-1 levels. CONCLUSIONS PQQ resists atrophic effect dependent on, at least in part, decreased ROS in skeletal muscle treated with TNF-α.
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Affiliation(s)
- Tongtong Xu
- Laboratory of Neuroregeneration, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
- School of Medicine, Nantong University, Nantong 226001, China
| | - Xiaoming Yang
- Laboratory of Neuroregeneration, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Changyue Wu
- School of Medicine, Nantong University, Nantong 226001, China
| | - Jiaying Qiu
- Laboratory of Neuroregeneration, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Qingqing Fang
- Laboratory of Neuroregeneration, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Lingbin Wang
- Laboratory of Neuroregeneration, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Shu Yu
- Laboratory of Neuroregeneration, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Hualin Sun
- Laboratory of Neuroregeneration, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
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262
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Chen L, Zhu G, Johns EM, Yang X. TRIM11 activates the proteasome and promotes overall protein degradation by regulating USP14. Nat Commun 2018; 9:1223. [PMID: 29581427 PMCID: PMC5964324 DOI: 10.1038/s41467-018-03499-z] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Accepted: 02/19/2018] [Indexed: 12/27/2022] Open
Abstract
The proteasome is a complex protease critical for protein quality control and cell regulation, and its dysfunction is associated with cancer and other diseases. However, the mechanisms that control proteasome activity in normal and malignant cells remain unclear. Here we report that TRIM11 enhances degradation of aberrant and normal regulatory proteins, and augments overall rate of proteolysis. Mechanistically, TRIM11 binds to both the proteasome and USP14, a deubiquitinase that prematurely removes ubiquitins from proteasome-bound substrates and also noncatalytically inhibits the proteasome, and precludes their association, thereby increasing proteasome activity. TRIM11 promotes cell survival and is upregulated upon heat shock. Moreover, TRIM11 is required for tumor growth, and increased expression of TRIM11 correlates with poor clinical survival. These findings identify TRIM11 as an important activator of the proteasome, define a pathway that adjusts proteasome activity, and reveal a mechanism by which tumor cells acquire higher degradative power to support oncogenic growth. The proteasome-bound ubiquitinase USP14 plays an important role in determining proteasome activity and substrate specificity. Here the authors show that TRIM11, a member of the mammalian tripartite motif family, regulates USP14 and is an important activator of the proteasome.
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Affiliation(s)
- Liang Chen
- Department of Cancer Biology and Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Guixin Zhu
- Department of Cancer Biology and Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Eleanor M Johns
- Department of Cancer Biology and Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Xiaolu Yang
- Department of Cancer Biology and Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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263
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Sha Z, Schnell HM, Ruoff K, Goldberg A. Rapid induction of p62 and GABARAPL1 upon proteasome inhibition promotes survival before autophagy activation. J Cell Biol 2018. [PMID: 29535191 PMCID: PMC5940303 DOI: 10.1083/jcb.201708168] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Cells are thought to adapt to proteasome inhibition by using alternative pathways for degradation such as autophagy. Sha et al. now report that cells rapidly induce GABARAPL1 and p62 upon proteasome inhibition, but this promotes cell survival by sequestering ubiquitinated and sumoylated proteins long before the cells induce other Atg genes and activate autophagy. Proteasome inhibitors are used as research tools and to treat multiple myeloma, and proteasome activity is diminished in several neurodegenerative diseases. We therefore studied how cells compensate for proteasome inhibition. In 4 h, proteasome inhibitor treatment caused dramatic and selective induction of GABARAPL1 (but not other autophagy genes) and p62, which binds ubiquitinated proteins and GABARAPL1 on autophagosomes. Knockdown of p62 or GABARAPL1 reduced cell survival upon proteasome inhibition. p62 induction requires the transcription factor nuclear factor (erythroid-derived 2)-like 1 (Nrf1), which simultaneously induces proteasome genes. After 20-h exposure to proteasome inhibitors, cells activated autophagy and expression of most autophagy genes by an Nrf1-independent mechanism. Although p62 facilitates the association of ubiquitinated proteins with autophagosomes, its knockdown in neuroblastoma cells blocked the buildup of ubiquitin conjugates in perinuclear aggresomes and of sumoylated proteins in nuclear inclusions but did not reduce the degradation of ubiquitinated proteins. Thus, upon proteasome inhibition, cells rapidly induce p62 expression, which enhances survival primarily by sequestering ubiquitinated proteins in inclusions.
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Affiliation(s)
- Zhe Sha
- Harvard Medical School, Boston, MA
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264
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Abstract
Mechanistic target of rapamycin (mTOR) is the kinase subunit of two structurally and functionally distinct large multiprotein complexes, referred to as mTOR complex 1 (mTORC1) and mTORC2. mTORC1 and mTORC2 play key physiological roles as they control anabolic and catabolic processes in response to external cues in a variety of tissues and organs. However, mTORC1 and mTORC2 activities are deregulated in widespread human diseases, including cancer. Cancer cells take advantage of mTOR oncogenic signaling to drive their proliferation, survival, metabolic transformation, and metastatic potential. Therefore, mTOR lends itself very well as a therapeutic target for innovative cancer treatment. mTOR was initially identified as the target of the antibiotic rapamycin that displayed remarkable antitumor activity in vitro Promising preclinical studies using rapamycin and its derivatives (rapalogs) demonstrated efficacy in many human cancer types, hence supporting the launch of numerous clinical trials aimed to evaluate the real effectiveness of mTOR-targeted therapies. However, rapamycin and rapalogs have shown very limited activity in most clinical contexts, also when combined with other drugs. Thus, novel classes of mTOR inhibitors with a stronger antineoplastic potency have been developed. Nevertheless, emerging clinical data suggest that also these novel mTOR-targeting drugs may have a weak antitumor activity. Here, we summarize the current status of available mTOR inhibitors and highlight the most relevant results from both preclinical and clinical studies that have provided valuable insights into both their efficacy and failure.
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265
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Struchtrup A, Wiegering A, Stork B, Rüther U, Gerhardt C. The ciliary protein RPGRIP1L governs autophagy independently of its proteasome-regulating function at the ciliary base in mouse embryonic fibroblasts. Autophagy 2018; 14:567-583. [PMID: 29372668 PMCID: PMC5959336 DOI: 10.1080/15548627.2018.1429874] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Previously, macroautophagy/autophagy was demonstrated to be regulated inter alia by the primary cilium. Mutations in RPGRIP1L cause ciliary dysfunctions resulting in severe human diseases summarized as ciliopathies. Recently, we showed that RPGRIP1L deficiency leads to a decreased proteasomal activity at the ciliary base in mice. Importantly, the drug-induced restoration of proteasomal activity does not rescue ciliary length alterations in the absence of RPGRIP1L indicating that RPGRIP1L affects ciliary function also via other mechanisms. Based on this knowledge, we analyzed autophagy in Rpgrip1l-negative mouse embryos. In these embryos, autophagic activity was decreased due to an increased activation of the MTOR complex 1 (MTORC1). Application of the MTORC1 inhibitor rapamycin rescued dysregulated MTORC1, autophagic activity and cilia length but not proteasomal activity in Rpgrip1l-deficient mouse embryonic fibroblasts demonstrating that RPGRIP1L seems to regulate autophagic and proteasomal activity independently from each other.
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Affiliation(s)
- Andreas Struchtrup
- a Institute for Animal Developmental and Molecular Biology, Heinrich-Heine University Düsseldorf , Düsseldorf , Germany
| | - Antonia Wiegering
- a Institute for Animal Developmental and Molecular Biology, Heinrich-Heine University Düsseldorf , Düsseldorf , Germany
| | - Björn Stork
- b Institute of Molecular Medicine I, Medical Faculty, Heinrich-Heine University Düsseldorf , Düsseldorf , Germany
| | - Ulrich Rüther
- a Institute for Animal Developmental and Molecular Biology, Heinrich-Heine University Düsseldorf , Düsseldorf , Germany
| | - Christoph Gerhardt
- a Institute for Animal Developmental and Molecular Biology, Heinrich-Heine University Düsseldorf , Düsseldorf , Germany
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266
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Perez-Alvarez MJ, Villa Gonzalez M, Benito-Cuesta I, Wandosell FG. Role of mTORC1 Controlling Proteostasis after Brain Ischemia. Front Neurosci 2018; 12:60. [PMID: 29497356 PMCID: PMC5818460 DOI: 10.3389/fnins.2018.00060] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 01/24/2018] [Indexed: 01/24/2023] Open
Abstract
Intense efforts are being undertaken to understand the pathophysiological mechanisms triggered after brain ischemia and to develop effective pharmacological treatments. However, the underlying molecular mechanisms are complex and not completely understood. One of the main problems is the fact that the ischemic damage is time-dependent and ranges from negligible to massive, involving different cell types such as neurons, astrocytes, microglia, endothelial cells, and some blood-derived cells (neutrophils, lymphocytes, etc.). Thus, approaching such a complicated cellular response generates a more complex combination of molecular mechanisms, in which cell death, cellular damage, stress and repair are intermixed. For this reason, animal and cellular model systems are needed in order to dissect and clarify which molecular mechanisms have to be promoted and/or blocked. Brain ischemia may be analyzed from two different perspectives: that of oxygen deprivation (hypoxic damage per se) and that of deprivation of glucose/serum factors. For investigations of ischemic stroke, middle cerebral artery occlusion (MCAO) is the preferred in vivo model, and uses two different approaches: transient (tMCAO), where reperfusion is permitted; or permanent (pMCAO). As a complement to this model, many laboratories expose different primary cortical neuron or neuronal cell lines to oxygen-glucose deprivation (OGD). This ex vivo model permits the analysis of the impact of hypoxic damage and the specific response of different cell types implicated in vivo, such as neurons, glia or endothelial cells. Using in vivo and neuronal OGD models, it was recently established that mTORC1 (mammalian Target of Rapamycin Complex-1), a protein complex downstream of PI3K-Akt pathway, is one of the players deregulated after ischemia and OGD. In addition, neuroprotective intervention either by estradiol or by specific AT2R agonists shows an important regulatory role for the mTORC1 activity, for instance regulating vascular endothelial growth factor (VEGF) levels. This evidence highlights the importance of understanding the role of mTORC1 in neuronal death/survival processes, as it could be a potential therapeutic target. This review summarizes the state-of-the-art of the complex kinase mTORC1 focusing in upstream and downstream pathways, their role in central nervous system and their relationship with autophagy, apoptosis and neuroprotection/neurodegeneration after ischemia/hypoxia.
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Affiliation(s)
- Maria J Perez-Alvarez
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain.,Departamento de Biología (Fisiología Animal), Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain.,Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas, Madrid, Spain
| | - Mario Villa Gonzalez
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain.,Departamento de Biología (Fisiología Animal), Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| | - Irene Benito-Cuesta
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain.,Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas, Madrid, Spain
| | - Francisco G Wandosell
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain.,Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas, Madrid, Spain
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267
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Abstract
The mitochondrial network is not only required for the production of energy, essential cofactors and amino acids, but also serves as a signaling hub for innate immune and apoptotic pathways. Multiple mechanisms have evolved to identify and combat mitochondrial dysfunction to maintain the health of the organism. One such pathway is the mitochondrial unfolded protein response (UPRmt), which is regulated by the mitochondrial import efficiency of the transcription factor ATFS-1 in C. elegans and potentially orthologous transcription factors in mammals (ATF4, ATF5, CHOP). Upon mitochondrial dysfunction, import of ATFS-1 into mitochondria is reduced, allowing it to be trafficked to the nucleus where it promotes the expression of genes that promote survival and recovery of the mitochondrial network. Here, we discuss recent findings underlying UPRmt signal transduction and how this adaptive transcriptional response may interact with other mitochondrial stress response pathways.
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268
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269
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Abstract
Rates of degradation by the ubiquitin proteasome system depend not only on rates of ubiquitination, but also on the level of proteasome activity which can be regulated through phosphorylation of proteasome subunits. Many protein kinases have been proposed to influence proteasomal activity. However, for only two is there strong evidence that phosphorylation of a specific 26S subunit enhances the proteasome's capacity to degrade ubiquitinated proteins and promotes protein breakdown in cells: (1) protein kinase A (PKA), which after a rise in cAMP phosphorylates the 19S subunit Rpn6, and (2) dual tyrosine receptor kinase 2 (DYRK2), which during S through M phases of the cell cycle phosphorylates the 19S ATPase subunit Rpt3. In this chapter, we review and discuss the different methods used to assess the impact of phosphorylation by these two kinases on proteasomal activity and intracellular protein degradation. In addition, we present one method to determine if phosphorylation is responsible for an observed increase in proteasomal activity and another to evaluate by Phos-tag gel electrophoresis whether a specific proteasome subunit is modified by phosphorylation. The methods reviewed and presented here should be useful in clarifying the roles of other kinases and other posttranslational modifications of proteasome subunits.
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270
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Sha Z, Zhao J, Goldberg AL. Measuring the Overall Rate of Protein Breakdown in Cells and the Contributions of the Ubiquitin-Proteasome and Autophagy-Lysosomal Pathways. Methods Mol Biol 2018; 1844:261-276. [PMID: 30242715 PMCID: PMC6441977 DOI: 10.1007/978-1-4939-8706-1_17] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In certain physiological or pathological states (e.g., starvation, heat shock, or muscle atrophy) and upon drug treatments, the overall rate of protein degradation in cells may increase or decrease. These adaptations and pathological responses can occur through alterations in substrate flux through the ubiquitin-proteasome pathway (UPP), the autophagy-lysosomal system, or both. Therefore, it is important to precisely measure the activities of these degradation pathways in degrading cell proteins under different physiological states or upon treatment with drugs. In particular, proteasome inhibitors have become very important agents for treating multiple myeloma and very useful tools in basic research. To evaluate rigorously their efficacy and the cellular responses to other inhibitors, it is essential to know the degree of inhibition of protein breakdown. Unfortunately, commonly used assays of the activities of the UPP or autophagy rely on qualitative, indirect approaches that do not directly reflect the actual rates of protein degradation by these pathways. In this chapter, we describe isotopic pulse-chase methods to directly measure overall rates of protein degradation in cells by radiolabeling cell proteins and following their subsequent degradation to radioactive amino acids, which diffuse from cells into the medium and can be easily quantitated. While pulse-chase methods have often been used to follow degradation of specific proteins, the methods described here allow quantification of the total cellular activity in degrading either long-lived proteins (the great bulk of cell constituents) or the fraction with short half-lives. Moreover, by use of specific inhibitors of proteasomes or lysosomes, it is also possible to measure precisely the total contributions of the UPP or lysosomal proteases. These approaches have already been proven very useful in defining the effects of inhibitors, growth factors, nutrients, ubiquitination, and different proteasome activators on overall proteolysis and on substrate flux through the proteasomal and lysosomal pathways.
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Affiliation(s)
- Zhe Sha
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Jinghui Zhao
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
- AbbVie, Cambridge, MA, USA
| | - Alfred L Goldberg
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA.
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271
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Jüppner J, Mubeen U, Leisse A, Caldana C, Wiszniewski A, Steinhauser D, Giavalisco P. The target of rapamycin kinase affects biomass accumulation and cell cycle progression by altering carbon/nitrogen balance in synchronized Chlamydomonas reinhardtii cells. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 93:355-376. [PMID: 29172247 DOI: 10.1111/tpj.13787] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Revised: 10/31/2017] [Accepted: 11/15/2017] [Indexed: 05/19/2023]
Abstract
Several metabolic processes tightly regulate growth and biomass accumulation. A highly conserved protein complex containing the target of rapamycin (TOR) kinase is known to integrate intra- and extracellular stimuli controlling nutrient allocation and hence cellular growth. Although several functions of TOR have been described in various heterotrophic eukaryotes, our understanding lags far behind in photosynthetic organisms. In the present investigation, we used the model alga Chlamydomonas reinhardtii to conduct a time-resolved analysis of molecular and physiological features throughout the diurnal cycle after TOR inhibition. Detailed examination of the cell cycle phases revealed that growth is not only repressed by 50%, but also that significant, non-linear delays in the progression can be observed. By using metabolomics analysis, we elucidated that the growth repression was mainly driven by differential carbon partitioning between anabolic and catabolic processes. Accordingly, the time-resolved analysis illustrated that metabolic processes including amino acid-, starch- and triacylglycerol synthesis, as well RNA degradation, were redirected within minutes of TOR inhibition. Here especially the high accumulation of nitrogen-containing compounds indicated that an active TOR kinase controls the carbon to nitrogen balance of the cell, which is responsible for biomass accumulation, growth and cell cycle progression.
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Affiliation(s)
- Jessica Jüppner
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Umarah Mubeen
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Andrea Leisse
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Camila Caldana
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
- Brazilian Bioethanol Science and Technology Laboratory/CNPEM, Rua Giuseppe Máximo Scolfano 10000, 13083-970, Campinas, Brazil
| | - Andrew Wiszniewski
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Dirk Steinhauser
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Patrick Giavalisco
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
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272
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Cai X, Yuan Y, Liao Z, Xing K, Zhu C, Xu Y, Yu L, Wang L, Wang S, Zhu X, Gao P, Zhang Y, Jiang Q, Xu P, Shu G. α-Ketoglutarate prevents skeletal muscle protein degradation and muscle atrophy through PHD3/ADRB2 pathway. FASEB J 2018; 32:488-499. [PMID: 28939592 PMCID: PMC6266637 DOI: 10.1096/fj.201700670r] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 09/05/2017] [Indexed: 12/20/2022]
Abstract
Skeletal muscle atrophy due to excessive protein degradation is the main cause for muscle dysfunction, fatigue, and weakening of athletic ability. Endurance exercise is effective to attenuate muscle atrophy, but the underlying mechanism has not been fully investigated. α-Ketoglutarate (AKG) is a key intermediate of tricarboxylic acid cycle, which is generated during endurance exercise. Here, we demonstrated that AKG effectively attenuated corticosterone-induced protein degradation and rescued the muscle atrophy and dysfunction in a Duchenne muscular dystrophy mouse model. Interestingly, AKG also inhibited the expression of proline hydroxylase 3 (PHD3), one of the important oxidoreductases expressed under hypoxic conditions. Subsequently, we identified the β2 adrenergic receptor (ADRB2) as a downstream target for PHD3. We found AKG inhibited PHD3/ADRB2 interaction and therefore increased the stability of ADRB2. In addition, combining pharmacologic and genetic approaches, we showed that AKG rescues skeletal muscle atrophy and protein degradation through a PHD3/ADRB2 mediated mechanism. Taken together, these data reveal a mechanism for inhibitory effects of AKG on muscle atrophy and protein degradation. These findings not only provide a molecular basis for the potential use of exercise-generated metabolite AKG in muscle atrophy treatment, but also identify PHD3 as a potential target for the development of therapies for muscle wasting.-Cai, X., Yuan, Y., Liao, Z., Xing, K., Zhu, C., Xu, Y., Yu, L., Wang, L., Wang, S., Zhu, X., Gao, P., Zhang, Y., Jiang, Q., Xu, P., Shu, G. α-Ketoglutarate prevents skeletal muscle protein degradation and muscle atrophy through PHD3/ADRB2 pathway.
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MESH Headings
- Animals
- Corticosterone/pharmacology
- Disease Models, Animal
- Ketoglutaric Acids/therapeutic use
- Male
- Metabolic Networks and Pathways/drug effects
- Mice
- Mice, Inbred C57BL
- Mice, Inbred mdx
- Muscle Fibers, Skeletal/drug effects
- Muscle Fibers, Skeletal/pathology
- Muscle Proteins/metabolism
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Muscular Atrophy/metabolism
- Muscular Atrophy/pathology
- Muscular Atrophy/prevention & control
- Muscular Dystrophy, Duchenne/drug therapy
- Muscular Dystrophy, Duchenne/metabolism
- Muscular Dystrophy, Duchenne/pathology
- Procollagen-Proline Dioxygenase/metabolism
- Protein Stability/drug effects
- Proteolysis/drug effects
- Receptors, Adrenergic, beta-2/metabolism
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Affiliation(s)
- Xingcai Cai
- Guangdong Provincial Key Laboratory of Animal Nutritional Control, South China Agricultural University, Guangzhou, China
| | - Yexian Yuan
- Guangdong Provincial Key Laboratory of Animal Nutritional Control, South China Agricultural University, Guangzhou, China
| | - Zhengrui Liao
- Guangdong Provincial Key Laboratory of Animal Nutritional Control, South China Agricultural University, Guangzhou, China
| | - Kongping Xing
- Guangdong Provincial Key Laboratory of Animal Nutritional Control, South China Agricultural University, Guangzhou, China
| | - Canjun Zhu
- Guangdong Provincial Key Laboratory of Animal Nutritional Control, South China Agricultural University, Guangzhou, China
| | - Yaqiong Xu
- Guangdong Provincial Key Laboratory of Animal Nutritional Control, South China Agricultural University, Guangzhou, China
| | - Lulu Yu
- Guangdong Provincial Key Laboratory of Animal Nutritional Control, South China Agricultural University, Guangzhou, China
| | - Lina Wang
- Guangdong Provincial Key Laboratory of Animal Nutritional Control, South China Agricultural University, Guangzhou, China
| | - Songbo Wang
- Guangdong Provincial Key Laboratory of Animal Nutritional Control, South China Agricultural University, Guangzhou, China
| | - Xiaotong Zhu
- Guangdong Provincial Key Laboratory of Animal Nutritional Control, South China Agricultural University, Guangzhou, China
| | - Ping Gao
- Guangdong Provincial Key Laboratory of Animal Nutritional Control, South China Agricultural University, Guangzhou, China
| | - Yongliang Zhang
- Guangdong Provincial Key Laboratory of Animal Nutritional Control, South China Agricultural University, Guangzhou, China
| | - Qingyan Jiang
- Guangdong Provincial Key Laboratory of Animal Nutritional Control, South China Agricultural University, Guangzhou, China
- National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Pingwen Xu
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Gang Shu
- Guangdong Provincial Key Laboratory of Animal Nutritional Control, South China Agricultural University, Guangzhou, China;
- National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, China
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273
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Ghosh A, Tyson T, George S, Hildebrandt EN, Steiner JA, Madaj Z, Schulz E, Machiela E, McDonald WG, Escobar Galvis ML, Kordower JH, Van Raamsdonk JM, Colca JR, Brundin P. Mitochondrial pyruvate carrier regulates autophagy, inflammation, and neurodegeneration in experimental models of Parkinson's disease. Sci Transl Med 2017; 8:368ra174. [PMID: 27928028 DOI: 10.1126/scitranslmed.aag2210] [Citation(s) in RCA: 128] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 11/17/2016] [Indexed: 12/15/2022]
Abstract
Mitochondrial and autophagic dysfunction as well as neuroinflammation are involved in the pathophysiology of Parkinson's disease (PD). We hypothesized that targeting the mitochondrial pyruvate carrier (MPC), a key controller of cellular metabolism that influences mTOR (mammalian target of rapamycin) activation, might attenuate neurodegeneration of nigral dopaminergic neurons in animal models of PD. To test this, we used MSDC-0160, a compound that specifically targets MPC, to reduce its activity. MSDC-0160 protected against 1-methyl-4-phenylpyridinium (MPP+) insult in murine and cultured human midbrain dopamine neurons and in an α-synuclein-based Caenorhabditis elegans model. In 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice, MSDC-0160 improved locomotor behavior, increased survival of nigral dopaminergic neurons, boosted striatal dopamine levels, and reduced neuroinflammation. Long-term targeting of MPC preserved motor function, rescued the nigrostriatal pathway, and reduced neuroinflammation in the slowly progressive Engrailed1 (En1+/-) genetic mouse model of PD. Targeting MPC in multiple models resulted in modulation of mitochondrial function and mTOR signaling, with normalization of autophagy and a reduction in glial cell activation. Our work demonstrates that changes in metabolic signaling resulting from targeting MPC were neuroprotective and anti-inflammatory in several PD models, suggesting that MPC may be a useful therapeutic target in PD.
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Affiliation(s)
- Anamitra Ghosh
- Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - Trevor Tyson
- Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - Sonia George
- Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - Erin N Hildebrandt
- Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - Jennifer A Steiner
- Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - Zachary Madaj
- Bioinformatics and Biostatistics Core, Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - Emily Schulz
- Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - Emily Machiela
- Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | | | - Martha L Escobar Galvis
- Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - Jeffrey H Kordower
- Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, MI 49503, USA.,Center for Brain Repair, Department of Pathology, Rush Medical College, Chicago, IL 60612, USA
| | - Jeremy M Van Raamsdonk
- Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - Jerry R Colca
- Metabolic Solutions Development Company, Kalamazoo, MI 49007, USA
| | - Patrik Brundin
- Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, MI 49503, USA.
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274
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Hartupee J, Szalai GD, Wang W, Ma X, Diwan A, Mann DL. Impaired Protein Quality Control During Left Ventricular Remodeling in Mice With Cardiac Restricted Overexpression of Tumor Necrosis Factor. Circ Heart Fail 2017; 10:CIRCHEARTFAILURE.117.004252. [PMID: 29203562 DOI: 10.1161/circheartfailure.117.004252] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 11/09/2017] [Indexed: 11/16/2022]
Abstract
BACKGROUND Sustained inflammation in the heart is sufficient to provoke left ventricular dysfunction and left ventricular remodeling. Although inflammation has been linked to many of the biological changes responsible for adverse left ventricular remodeling, the relationship between inflammation and protein quality control in the heart is not well understood. METHODS AND RESULTS To study the relationship between chronic inflammation and protein quality control, we used a mouse model of dilated cardiomyopathy driven by cardiac restricted overexpression of TNF (tumor necrosis factor; Myh6-sTNF). Myh6-sTNF mice develop protein aggregates containing ubiquitin-tagged proteins within cardiac myocytes related to proteasome dysfunction and impaired autophagy. The 26S proteasome was dysfunctional despite normal function of the core 20S subunit. We found an accumulation of autophagy substrates in Myh6-sTNF mice, which were also seen in tissue from patients with end-stage heart failure. Moreover, there was evidence of impaired autophagosome clearance after chloroquine administration in these mice indicative of impaired autophagic flux. Finally, there was increased mammalian target of rapamycin complex 1 (mTORC1) activation, which has been linked to inhibition of both the proteasome and autophagy. CONCLUSIONS Myh6-sTNF mice with sustained inflammatory signaling develop proteasome dysfunction and impaired autophagic flux that is associated with enhanced mTORC1 activation.
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Affiliation(s)
- Justin Hartupee
- From the Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, MO (J.H., X.M., A.D., D.L.M.); John Cochran VA Medical Center, St. Louis, MO (A.D.); and Winters Center for Heart Failure Research, Section of Cardiology, Department of Medicine, Baylor College of Medicine, Houston, TX (G.D.S., W.W.)
| | - Gabor D Szalai
- From the Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, MO (J.H., X.M., A.D., D.L.M.); John Cochran VA Medical Center, St. Louis, MO (A.D.); and Winters Center for Heart Failure Research, Section of Cardiology, Department of Medicine, Baylor College of Medicine, Houston, TX (G.D.S., W.W.)
| | - Wei Wang
- From the Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, MO (J.H., X.M., A.D., D.L.M.); John Cochran VA Medical Center, St. Louis, MO (A.D.); and Winters Center for Heart Failure Research, Section of Cardiology, Department of Medicine, Baylor College of Medicine, Houston, TX (G.D.S., W.W.)
| | - Xiucui Ma
- From the Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, MO (J.H., X.M., A.D., D.L.M.); John Cochran VA Medical Center, St. Louis, MO (A.D.); and Winters Center for Heart Failure Research, Section of Cardiology, Department of Medicine, Baylor College of Medicine, Houston, TX (G.D.S., W.W.)
| | - Abhinav Diwan
- From the Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, MO (J.H., X.M., A.D., D.L.M.); John Cochran VA Medical Center, St. Louis, MO (A.D.); and Winters Center for Heart Failure Research, Section of Cardiology, Department of Medicine, Baylor College of Medicine, Houston, TX (G.D.S., W.W.)
| | - Douglas L Mann
- From the Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, MO (J.H., X.M., A.D., D.L.M.); John Cochran VA Medical Center, St. Louis, MO (A.D.); and Winters Center for Heart Failure Research, Section of Cardiology, Department of Medicine, Baylor College of Medicine, Houston, TX (G.D.S., W.W.).
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275
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Antikainen H, Driscoll M, Haspel G, Dobrowolski R. TOR-mediated regulation of metabolism in aging. Aging Cell 2017; 16:1219-1233. [PMID: 28971552 PMCID: PMC5676073 DOI: 10.1111/acel.12689] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/03/2017] [Indexed: 01/06/2023] Open
Abstract
Cellular metabolism is regulated by the mTOR kinase, a key component of the molecular nutrient sensor pathway that plays a central role in cellular survival and aging. The mTOR pathway promotes protein and lipid synthesis and inhibits autophagy, a process known for its contribution to longevity in several model organisms. The nutrient‐sensing pathway is regulated at the lysosomal membrane by a number of proteins for which deficiency triggers widespread aging phenotypes in tested animal models. In response to environmental cues, this recently discovered lysosomal nutrient‐sensing complex regulates autophagy transcriptionally through conserved factors, such as the transcription factors TFEB and FOXO, associated with lifespan extension. This key metabolic pathway strongly depends on nucleocytoplasmic compartmentalization, a cellular phenomenon gradually lost during aging. In this review, we discuss the current progress in understanding the contribution of mTOR‐regulating factors to autophagy and longevity. Furthermore, we review research on the regulation of metabolism conducted in multiple aging models, including Caenorhabditis elegans, Drosophila and mouse, and human iPSCs. We suggest that conserved molecular pathways have the strongest potential for the development of new avenues for treatment of age‐related diseases.
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Affiliation(s)
- Henri Antikainen
- Federated Department of Biological Sciences New Jersey Institute of Technology Rutgers University Newark NJ 07102 USA
| | - Monica Driscoll
- Department of Molecular Biology and Biochemistry Rutgers University Piscataway NJ 08854 USA
| | - Gal Haspel
- Federated Department of Biological Sciences New Jersey Institute of Technology Rutgers University Newark NJ 07102 USA
| | - Radek Dobrowolski
- Federated Department of Biological Sciences New Jersey Institute of Technology Rutgers University Newark NJ 07102 USA
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276
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VerPlank JJS, Lokireddy S, Feltri ML, Goldberg AL, Wrabetz L. Impairment of protein degradation and proteasome function in hereditary neuropathies. Glia 2017; 66:379-395. [PMID: 29076578 DOI: 10.1002/glia.23251] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 09/10/2017] [Accepted: 10/09/2017] [Indexed: 01/02/2023]
Abstract
In several neurodegenerative diseases in which misfolded proteins accumulate there is impairment of the ubiquitin proteasome system (UPS). We tested if a similar disruption of proteostasis occurs in hereditary peripheral neuropathies. In sciatic nerves from mouse models of two human neuropathies, Myelin Protein Zero mutation (S63del) and increased copy number (P0 overexpression), polyubiquitinated proteins accumulated, and the overall rates of protein degradation were decreased. 26S proteasomes affinity-purified from sciatic nerves of S63del mice were defective in degradation of peptides and a ubiquitinated protein, unlike proteasomes from P0 overexpression, which appeared normal. Nevertheless, cellular levels of 26S proteasomes were increased in both, through the proteolytic-activation of the transcription factor Nrf1, as occurs in response to proteasome inhibitors. In S63del, increased amounts of the deubiquitinating enzymes USP14, UCH37, and USP5 were associated with proteasomes, the first time this has been reported in a human disease model. Inhibitors of USP14 increased the rate of protein degradation in S63del sciatic nerves and unexpectedly increased the phosphorylation of eIF2α by Perk. Thus, proteasome content, composition and activity are altered in these diseases and USP14 inhibitors have therapeutic potential in S63del neuropathy.
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Affiliation(s)
- Jordan J S VerPlank
- Hunter James Kelly Research Institute and Departments of, Biochemistry and Neurology, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York.,Harvard Medical School, Boston, Massachusetts
| | | | - M Laura Feltri
- Hunter James Kelly Research Institute and Departments of, Biochemistry and Neurology, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York
| | | | - Lawrence Wrabetz
- Hunter James Kelly Research Institute and Departments of, Biochemistry and Neurology, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York
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277
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Abu-Remaileh M, Wyant GA, Kim C, Laqtom NN, Abbasi M, Chan SH, Freinkman E, Sabatini DM. Lysosomal metabolomics reveals V-ATPase- and mTOR-dependent regulation of amino acid efflux from lysosomes. Science 2017; 358:807-813. [PMID: 29074583 DOI: 10.1126/science.aan6298] [Citation(s) in RCA: 382] [Impact Index Per Article: 54.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 10/03/2017] [Indexed: 01/09/2023]
Abstract
The lysosome degrades and recycles macromolecules, signals to the cytosol and nucleus, and is implicated in many diseases. Here, we describe a method for the rapid isolation of mammalian lysosomes and use it to quantitatively profile lysosomal metabolites under various cell states. Under nutrient-replete conditions, many lysosomal amino acids are in rapid exchange with those in the cytosol. Loss of lysosomal acidification through inhibition of the vacuolar H+-adenosine triphosphatase (V-ATPase) increased the luminal concentrations of most metabolites but had no effect on those of the majority of essential amino acids. Instead, nutrient starvation regulates the lysosomal concentrations of these amino acids, an effect we traced to regulation of the mechanistic target of rapamycin (mTOR) pathway. Inhibition of mTOR strongly reduced the lysosomal efflux of most essential amino acids, converting the lysosome into a cellular depot for them. These results reveal the dynamic nature of lysosomal metabolites and that V-ATPase- and mTOR-dependent mechanisms exist for controlling lysosomal amino acid efflux.
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Affiliation(s)
- Monther Abu-Remaileh
- Whitehead Institute for Biomedical Research and Massachusetts Institute of Technology, Department of Biology, 9 Cambridge Center, Cambridge, MA 02142, USA.,Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Koch Institute for Integrative Cancer Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.,Broad Institute of Harvard and Massachusetts Institute of Technology, 7 Cambridge Center, Cambridge, MA 02142, USA
| | - Gregory A Wyant
- Whitehead Institute for Biomedical Research and Massachusetts Institute of Technology, Department of Biology, 9 Cambridge Center, Cambridge, MA 02142, USA.,Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Koch Institute for Integrative Cancer Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.,Broad Institute of Harvard and Massachusetts Institute of Technology, 7 Cambridge Center, Cambridge, MA 02142, USA
| | - Choah Kim
- Whitehead Institute for Biomedical Research and Massachusetts Institute of Technology, Department of Biology, 9 Cambridge Center, Cambridge, MA 02142, USA.,Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Koch Institute for Integrative Cancer Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.,Broad Institute of Harvard and Massachusetts Institute of Technology, 7 Cambridge Center, Cambridge, MA 02142, USA
| | - Nouf N Laqtom
- Whitehead Institute for Biomedical Research and Massachusetts Institute of Technology, Department of Biology, 9 Cambridge Center, Cambridge, MA 02142, USA.,Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Koch Institute for Integrative Cancer Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.,Broad Institute of Harvard and Massachusetts Institute of Technology, 7 Cambridge Center, Cambridge, MA 02142, USA
| | - Maria Abbasi
- Whitehead Institute for Biomedical Research and Massachusetts Institute of Technology, Department of Biology, 9 Cambridge Center, Cambridge, MA 02142, USA.,Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Koch Institute for Integrative Cancer Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.,Broad Institute of Harvard and Massachusetts Institute of Technology, 7 Cambridge Center, Cambridge, MA 02142, USA
| | - Sze Ham Chan
- Whitehead Institute for Biomedical Research and Massachusetts Institute of Technology, Department of Biology, 9 Cambridge Center, Cambridge, MA 02142, USA
| | - Elizaveta Freinkman
- Whitehead Institute for Biomedical Research and Massachusetts Institute of Technology, Department of Biology, 9 Cambridge Center, Cambridge, MA 02142, USA
| | - David M Sabatini
- Whitehead Institute for Biomedical Research and Massachusetts Institute of Technology, Department of Biology, 9 Cambridge Center, Cambridge, MA 02142, USA. .,Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Koch Institute for Integrative Cancer Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.,Broad Institute of Harvard and Massachusetts Institute of Technology, 7 Cambridge Center, Cambridge, MA 02142, USA
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278
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Niklison-Chirou MV, Erngren I, Engskog M, Haglöf J, Picard D, Remke M, McPolin PHR, Selby M, Williamson D, Clifford SC, Michod D, Hadjiandreou M, Arvidsson T, Pettersson C, Melino G, Marino S. TAp73 is a marker of glutamine addiction in medulloblastoma. Genes Dev 2017; 31:1738-1753. [PMID: 28971956 PMCID: PMC5666673 DOI: 10.1101/gad.302349.117] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 09/05/2017] [Indexed: 12/21/2022]
Abstract
Medulloblastoma is the most common solid primary brain tumor in children. Remarkable advancements in the understanding of the genetic and epigenetic basis of these tumors have informed their recent molecular classification. However, the genotype/phenotype correlation of the subgroups remains largely uncharacterized. In particular, the metabolic phenotype is of great interest because of its druggability, which could lead to the development of novel and more tailored therapies for a subset of medulloblastoma. p73 plays a critical role in a range of cellular metabolic processes. We show overexpression of p73 in a proportion of non-WNT medulloblastoma. In these tumors, p73 sustains cell growth and proliferation via regulation of glutamine metabolism. We validated our results in a xenograft model in which we observed an increase in survival time in mice on a glutamine restriction diet. Notably, glutamine starvation has a synergistic effect with cisplatin, a component of the current medulloblastoma chemotherapy. These findings raise the possibility that glutamine depletion can be used as an adjuvant treatment for p73-expressing medulloblastoma.
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Affiliation(s)
- Maria Victoria Niklison-Chirou
- Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AT, United Kingdom
| | - Ida Erngren
- Department of Medicinal Chemistry, Analytical Pharmaceutical Chemistry, Uppsala University, 751 23 Uppsala, Sweden
| | - Mikael Engskog
- Department of Medicinal Chemistry, Analytical Pharmaceutical Chemistry, Uppsala University, 751 23 Uppsala, Sweden
| | - Jakob Haglöf
- Department of Medicinal Chemistry, Analytical Pharmaceutical Chemistry, Uppsala University, 751 23 Uppsala, Sweden
| | - Daniel Picard
- Department of Pediatric Oncology, Hematology, and Clinical Immunology, Heinrich Heine University Dusseldorf, 40225 Dusseldorf, Germany.,Department of Neuropathology, Medical Faculty, Heinrich Heine University Dusseldorf, 40225 Dusseldorf, Germany.,Department of Pediatric Neuro-Oncogenomics, German Cancer Research Center (DKFZ), German Cancer Consortium (DKTK), 69120 Heidelberg, Germany
| | - Marc Remke
- Department of Pediatric Oncology, Hematology, and Clinical Immunology, Heinrich Heine University Dusseldorf, 40225 Dusseldorf, Germany.,Department of Neuropathology, Medical Faculty, Heinrich Heine University Dusseldorf, 40225 Dusseldorf, Germany.,Department of Pediatric Neuro-Oncogenomics, German Cancer Research Center (DKFZ), German Cancer Consortium (DKTK), 69120 Heidelberg, Germany
| | - Phelim Hugh Redmond McPolin
- Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AT, United Kingdom
| | - Matthew Selby
- Wolfson Childhood Cancer Research Centre, Northern Institute for Cancer Research, Newcastle University, Newcastle upon Tyne NE1 7RU, United Kingdom
| | - Daniel Williamson
- Wolfson Childhood Cancer Research Centre, Northern Institute for Cancer Research, Newcastle University, Newcastle upon Tyne NE1 7RU, United Kingdom
| | - Steven C Clifford
- Wolfson Childhood Cancer Research Centre, Northern Institute for Cancer Research, Newcastle University, Newcastle upon Tyne NE1 7RU, United Kingdom
| | - David Michod
- University College London, Institute of Child Health, London WC1N 1EH, United Kingdom
| | - Michalis Hadjiandreou
- Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AT, United Kingdom
| | - Torbjörn Arvidsson
- Department of Medicinal Chemistry, Analytical Pharmaceutical Chemistry, Uppsala University, 751 23 Uppsala, Sweden.,Medical Product Agency, SE-751 03 Uppsala, Sweden
| | - Curt Pettersson
- Department of Medicinal Chemistry, Analytical Pharmaceutical Chemistry, Uppsala University, 751 23 Uppsala, Sweden
| | - Gerry Melino
- Medical Research Council, Toxicology Unit, Leicester University, Leicester LE1 9HN, United Kingdom
| | - Silvia Marino
- Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AT, United Kingdom
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279
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Regulating protein breakdown through proteasome phosphorylation. Biochem J 2017; 474:3355-3371. [PMID: 28947610 DOI: 10.1042/bcj20160809] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 08/28/2017] [Accepted: 08/30/2017] [Indexed: 12/31/2022]
Abstract
The ubiquitin proteasome system degrades the great majority of proteins in mammalian cells. Countless studies have described how ubiquitination promotes the selective degradation of different cell proteins. However, there is a small but the growing literature that protein half-lives can also be regulated by post-translational modifications of the 26S proteasome. The present study reviews the ability of several kinases to alter proteasome function through subunit phosphorylation. For example, PKA (protein kinase A) and DYRK2 (dual-specificity tyrosine-regulated kinase 2) stimulate the proteasome's ability to degrade ubiquitinated proteins, peptides, and adenosine triphosphate, while one kinase, ASK1 (apoptosis signal-regulating kinase 1), inhibits proteasome function during apoptosis. Proteasome phosphorylation is likely to be important in regulating protein degradation because it occurs downstream from many hormones and neurotransmitters, in conditions that raise cyclic adenosine monophosphate or cyclic guanosine monophosphate levels, after calcium influx following synaptic depolarization, and during phases of the cell cycle. Beyond its physiological importance, pharmacological manipulation of proteasome phosphorylation has the potential to combat various diseases. Inhibitors of phosphodiesterases by activating PKA or PKG (protein kinase G) can stimulate proteasomal degradation of misfolded proteins that cause neurodegenerative or myocardial diseases and even reduce the associated pathology in mouse models. These observations are promising since in many proteotoxic diseases, aggregation-prone proteins impair proteasome function, and disrupt protein homeostasis. Conversely, preventing subunit phosphorylation by DYRK2 slows cell cycle progression and tumor growth. However, further research is essential to determine how phosphorylation of different subunits by these (or other) kinases alters the properties of this complex molecular machine and thus influence protein degradation rates.
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280
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Rhus coriaria increases protein ubiquitination, proteasomal degradation and triggers non-canonical Beclin-1-independent autophagy and apoptotic cell death in colon cancer cells. Sci Rep 2017; 7:11633. [PMID: 28912474 PMCID: PMC5599689 DOI: 10.1038/s41598-017-11202-3] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 08/21/2017] [Indexed: 12/19/2022] Open
Abstract
Colorectal cancer is the fourth leading cause of cancer-related deaths worldwide. Here, we investigated the anticancer effect of Rhus coriaria extract (RCE) on HT-29 and Caco-2 human colorectal cancer cells. We found that RCE significantly inhibited the viability and colony growth of colon cancer cells. Moreover, RCE induced Beclin-1-independent autophagy and subsequent caspase-7-dependent apoptosis. Blocking of autophagy by chloroquine significantly reduced RCE-induced cell death, while blocking of apoptosis had no effect on RCE-induced cell death. Mechanistically, RCE inactivated the AKT/mTOR pathway by promoting the proteasome-dependent degradation of both proteins. Strikingly, we also found that RCE targeted Beclin-1, p53 and procaspase-3 to degradation. Proteasome inhibition by MG-132 not only restored these proteins to level comparable to control cells, but also reduced RCE-induced cell death and blocked the activation of autophagy and apoptosis. The proteasomal degradation of mTOR, which occurred only 3 hours post-RCE treatment was concomitant with an overall increase in the level of ubiquitinated proteins and translated stimulation of proteolysis by the proteasome. Our findings demonstrate that Rhus coriaria possesses strong anti-colon cancer activity through stimulation of proteolysis as well as induction of autophagic and apoptotic cell death, making it a potential and valuable source of novel therapeutic cancer drug.
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281
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Qiu W, Sun B, He F, Zhang Y. MTA-induced Notch activation enhances the proliferation of human dental pulp cells by inhibiting autophagic flux. Int Endod J 2017; 50 Suppl 2:e52-e62. [DOI: 10.1111/iej.12811] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Accepted: 06/27/2017] [Indexed: 12/26/2022]
Affiliation(s)
- W. Qiu
- Graduate School at Shenzhen; Tsinghua University; Shenzhen China
- Department of Chemistry; Tsinghua University; Beijing China
- Key Lab in Healthy Science and Technology; Division of Life Science; Graduate School at Shenzhen; Tsinghua University; Shenzhen China
| | - B. Sun
- Graduate School at Shenzhen; Tsinghua University; Shenzhen China
- Key Lab in Healthy Science and Technology; Division of Life Science; Graduate School at Shenzhen; Tsinghua University; Shenzhen China
| | - F. He
- Department of Stomatology; the Second Clinical Medical College; Shenzhen People's Hospital; Jinan University; Shenzhen China
| | - Y. Zhang
- Key Lab in Healthy Science and Technology; Division of Life Science; Graduate School at Shenzhen; Tsinghua University; Shenzhen China
- Open FIESTA Center; Tsinghua University; Shenzhen China
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282
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James HA, O'Neill BT, Nair KS. Insulin Regulation of Proteostasis and Clinical Implications. Cell Metab 2017; 26:310-323. [PMID: 28712655 PMCID: PMC8020859 DOI: 10.1016/j.cmet.2017.06.010] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 05/02/2017] [Accepted: 06/14/2017] [Indexed: 02/01/2023]
Abstract
Maintenance and modification of the cellular proteome are at the core of normal cellular physiology. Although insulin is well known for its control of glucose homeostasis, its critical role in maintaining proteome homeostasis (proteostasis) is less appreciated. Insulin signaling regulates protein synthesis and degradation as well as posttranslational modifications at the tissue level and coordinates proteostasis at the organism level. Here, we review regulation of proteostasis by insulin in postabsorptive, postprandial, and diabetic states. We present the effects of insulin on amino acid flux in skeletal muscle and splanchnic tissues, the regulation of protein quality control, and turnover of mitochondrial protein pools in humans. We also review the current evidence for the mechanistic control of proteostasis by insulin and insulin-like growth factor 1 receptors based on preclinical studies. Finally, we discuss irreversible posttranslational modifications of the proteome in diabetes and how future investigations will provide new insights into mechanisms of diabetic complications.
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Affiliation(s)
- Haleigh A James
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Brian T O'Neill
- Division of Endocrinology and Metabolism, Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - K Sreekumaran Nair
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
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283
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Ricciardi MR, Mirabilii S, Licchetta R, Piedimonte M, Tafuri A. Targeting the Akt, GSK-3, Bcl-2 axis in acute myeloid leukemia. Adv Biol Regul 2017; 65:36-58. [PMID: 28549531 DOI: 10.1016/j.jbior.2017.05.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Revised: 05/16/2017] [Accepted: 05/16/2017] [Indexed: 06/07/2023]
Abstract
Over the last few decades, there has been significant progress in the understanding of the pathogenetic mechanisms of the Acute Myeloid Leukemia (AML). However, despite important advances in elucidating molecular mechanisms, the treatment of AML has not improved significantly, remaining anchored at the standard chemotherapy regimen "3 + 7", with the prognosis of patients remaining severe, especially for the elderly and for those not eligible for transplant procedures. The biological and clinical heterogeneity of AML represents the major obstacle that hinders the improvement of prognosis and the identification of new effective therapeutic approaches. To date, abundant information has been collected on the genetic and molecular alterations of AML carrying prognostic significance. However, not enough is known on how AML progenitors regulate proliferation and survival by redundant and cross-talking signal transduction pathways (STP). Furthermore, it remains unclear how such complicated network affects prognosis and therapeutic treatment options, although many of these molecular determinants are potentially attractive for their druggable characteristics. In this review, some of the key STP frequently deregulated in AML, such as PI3k/Akt/mTOR pathway, GSK3 and components of Bcl-2 family of proteins, are summarized, highlighting in addition their interplay. Based on this information, we reviewed new targeted therapeutic approaches, focusing on the aberrant networks that sustain the AML blast proliferation, survival and drug resistance, aiming to improve disease treatment. Finally, we reported the approaches aimed at disrupting key signaling cross-talk overcoming resistances based on the combination of different targeting therapeutic strategies.
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Affiliation(s)
- Maria Rosaria Ricciardi
- Hematology, "Sant'Andrea" Hospital-Sapienza, University of Rome, Department of Clinical and Molecular Medicine, Rome, Italy
| | - Simone Mirabilii
- Hematology, "Sant'Andrea" Hospital-Sapienza, University of Rome, Department of Clinical and Molecular Medicine, Rome, Italy.
| | - Roberto Licchetta
- Hematology, "Sant'Andrea" Hospital-Sapienza, University of Rome, Department of Clinical and Molecular Medicine, Rome, Italy
| | - Monica Piedimonte
- Hematology, "Sant'Andrea" Hospital-Sapienza, University of Rome, Department of Clinical and Molecular Medicine, Rome, Italy
| | - Agostino Tafuri
- Hematology, "Sant'Andrea" Hospital-Sapienza, University of Rome, Department of Clinical and Molecular Medicine, Rome, Italy
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284
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Yoon SO, Shin S, Karreth FA, Buel GR, Jedrychowski MP, Plas DR, Dedhar S, Gygi SP, Roux PP, Dephoure N, Blenis J. Focal Adhesion- and IGF1R-Dependent Survival and Migratory Pathways Mediate Tumor Resistance to mTORC1/2 Inhibition. Mol Cell 2017; 67:512-527.e4. [PMID: 28757207 DOI: 10.1016/j.molcel.2017.06.033] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 05/24/2017] [Accepted: 06/27/2017] [Indexed: 01/22/2023]
Abstract
Aberrant signaling by the mammalian target of rapamycin (mTOR) contributes to the devastating features of cancer cells. Thus, mTOR is a critical therapeutic target and catalytic inhibitors are being investigated as anti-cancer drugs. Although mTOR inhibitors initially block cell proliferation, cell viability and migration in some cancer cells are quickly restored. Despite sustained inhibition of mTORC1/2 signaling, Akt, a kinase regulating cell survival and migration, regains phosphorylation at its regulatory sites. Mechanistically, mTORC1/2 inhibition promotes reorganization of integrin/focal adhesion kinase-mediated adhesomes, induction of IGFR/IR-dependent PI3K activation, and Akt phosphorylation via an integrin/FAK/IGFR-dependent process. This resistance mechanism contributes to xenograft tumor cell growth, which is prevented with mTOR plus IGFR inhibitors, supporting this combination as a therapeutic approach for cancers.
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Affiliation(s)
- Sang-Oh Yoon
- Department of Pharmacology, Meyer Cancer Center, Weill Cornell Medical College, New York, NY 10065, USA.
| | - Sejeong Shin
- Department of Pharmacology, Meyer Cancer Center, Weill Cornell Medical College, New York, NY 10065, USA
| | - Florian A Karreth
- Department of Medicine, Meyer Cancer Center, Weill Cornell Medical College, New York, NY 10065, USA
| | - Gwen R Buel
- Department of Pharmacology, Meyer Cancer Center, Weill Cornell Medical College, New York, NY 10065, USA
| | | | - David R Plas
- Department of Cancer Biology, University of Cincinnati, Cincinnati, OH 45267, USA
| | - Shoukat Dedhar
- Department of Integrative Oncology, British Columbia Cancer Research Centre, Vancouver, BC V5Z 1L3, Canada
| | - Steven P Gygi
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Philippe P Roux
- Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Montreal, QC H3T 1J4, Canada
| | - Noah Dephoure
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
| | - John Blenis
- Department of Pharmacology, Meyer Cancer Center, Weill Cornell Medical College, New York, NY 10065, USA.
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285
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Lipton JO, Boyle LM, Yuan ED, Hochstrasser KJ, Chifamba FF, Nathan A, Tsai PT, Davis F, Sahin M. Aberrant Proteostasis of BMAL1 Underlies Circadian Abnormalities in a Paradigmatic mTOR-opathy. Cell Rep 2017; 20:868-880. [PMID: 28746872 PMCID: PMC5603761 DOI: 10.1016/j.celrep.2017.07.008] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 05/24/2017] [Accepted: 07/06/2017] [Indexed: 01/02/2023] Open
Abstract
Tuberous sclerosis complex (TSC) is a neurodevelopmental disorder characterized by mutations in either the TSC1 or TSC2 genes, whose products form a critical inhibitor of the mechanistic target of rapamycin (mTOR). Loss of TSC1/2 gene function renders an mTOR-overactivated state. Clinically, TSC manifests with epilepsy, intellectual disability, autism, and sleep dysfunction. Here, we report that mouse models of TSC have abnormal circadian rhythms. We show that mTOR regulates the proteostasis of the core clock protein BMAL1, affecting its translation, degradation, and subcellular localization. This results in elevated levels of BMAL1 and a dysfunctional clock that displays abnormal timekeeping under constant conditions and exaggerated responses to phase resetting. Genetically lowering the dose of BMAL1 rescues circadian behavioral phenotypes in TSC mouse models. These findings indicate that BMAL1 deregulation is a feature of the mTOR-activated state and suggest a molecular mechanism for mitigating circadian phenotypes in a neurodevelopmental disorder.
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Affiliation(s)
- Jonathan O Lipton
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA; Division of Sleep Medicine, Harvard Medical School, Boston, MA 02115, USA.
| | - Lara M Boyle
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA
| | - Elizabeth D Yuan
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA
| | - Kevin J Hochstrasser
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA
| | - Fortunate F Chifamba
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA
| | - Ashwin Nathan
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA
| | - Peter T Tsai
- Department of Neurology and Neurotherapeutics, University of Texas at Southwestern Medical Center, Dallas 73590, TX 75390, USA
| | - Fred Davis
- Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - Mustafa Sahin
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA.
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286
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The Logic of the 26S Proteasome. Cell 2017; 169:792-806. [PMID: 28525752 DOI: 10.1016/j.cell.2017.04.023] [Citation(s) in RCA: 562] [Impact Index Per Article: 80.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 04/13/2017] [Accepted: 04/14/2017] [Indexed: 12/14/2022]
Abstract
The ubiquitin proteasome pathway is responsible for most of the protein degradation in mammalian cells. Rates of degradation by this pathway have generally been assumed to be determined by rates of ubiquitylation. However, recent studies indicate that proteasome function is also tightly regulated and determines whether a ubiquitylated protein is destroyed or deubiquitylated and survives longer. This article reviews recent advances in our understanding of the proteasome's multistep ATP-dependent mechanism, its biochemical and structural features that ensure efficient proteolysis and ubiquitin recycling while preventing nonselective proteolysis, and the regulation of proteasome activity by interacting proteins and subunit modifications, especially phosphorylation.
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287
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Zabala-Letona A, Arruabarrena-Aristorena A, Martín-Martín N, Fernandez-Ruiz S, Sutherland JD, Clasquin M, Tomas-Cortazar J, Jimenez J, Torres I, Quang P, Ximenez-Embun P, Bago R, Ugalde-Olano A, Loizaga-Iriarte A, Lacasa-Viscasillas I, Unda M, Torrano V, Cabrera D, van Liempd SM, Cendon Y, Castro E, Murray S, Revandkar A, Alimonti A, Zhang Y, Barnett A, Lein G, Pirman D, Cortazar AR, Arreal L, Prudkin L, Astobiza I, Valcarcel-Jimenez L, Zuñiga-García P, Fernandez-Dominguez I, Piva M, Caro-Maldonado A, Sánchez-Mosquera P, Castillo-Martín M, Serra V, Beraza N, Gentilella A, Thomas G, Azkargorta M, Elortza F, Farràs R, Olmos D, Efeyan A, Anguita J, Muñoz J, Falcón-Pérez JM, Barrio R, Macarulla T, Mato JM, Martinez-Chantar ML, Cordon-Cardo C, Aransay AM, Marks K, Baselga J, Tabernero J, Nuciforo P, Manning BD, Marjon K, Carracedo A. mTORC1-dependent AMD1 regulation sustains polyamine metabolism in prostate cancer. Nature 2017; 547:109-113. [PMID: 28658205 PMCID: PMC5505479 DOI: 10.1038/nature22964] [Citation(s) in RCA: 137] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 05/04/2017] [Indexed: 02/07/2023]
Abstract
Activation of the PTEN-PI3K-mTORC1 pathway consolidates metabolic programs that sustain cancer cell growth and proliferation. Here we show that mechanistic target of rapamycin complex 1 (mTORC1) regulates polyamine dynamics, a metabolic route that is essential for oncogenicity. By using integrative metabolomics in a mouse model and human biopsies of prostate cancer, we identify alterations in tumours affecting the production of decarboxylated S-adenosylmethionine (dcSAM) and polyamine synthesis. Mechanistically, this metabolic rewiring stems from mTORC1-dependent regulation of S-adenosylmethionine decarboxylase 1 (AMD1) stability. This novel molecular regulation is validated in mouse and human cancer specimens. AMD1 is upregulated in human prostate cancer with activated mTORC1. Conversely, samples from a clinical trial with the mTORC1 inhibitor everolimus exhibit a predominant decrease in AMD1 immunoreactivity that is associated with a decrease in proliferation, in line with the requirement of dcSAM production for oncogenicity. These findings provide fundamental information about the complex regulatory landscape controlled by mTORC1 to integrate and translate growth signals into an oncogenic metabolic program.
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Affiliation(s)
- Amaia Zabala-Letona
- CIC bioGUNE, Bizkaia Technology Park, 801 building, 48160, Derio, Spain
- CIBERONC
| | | | | | | | | | | | | | - Jose Jimenez
- Vall d'Hebron Institute of Oncology (VHIO), Universidad Autonoma de Barcelona, Barcelona, Spain
| | - Ines Torres
- Department of Pathology, Vall d'Hebron Hospital, Universitat Autónoma de Barcelona, Barcelona, Spain
| | | | | | - Ruzica Bago
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, Scotland
| | | | | | | | - Miguel Unda
- Department of Urology, Basurto University Hospital, 48013, Bilbao, Spain
| | - Verónica Torrano
- CIC bioGUNE, Bizkaia Technology Park, 801 building, 48160, Derio, Spain
- CIBERONC
| | - Diana Cabrera
- CIC bioGUNE, Bizkaia Technology Park, 801 building, 48160, Derio, Spain
| | | | - Ylenia Cendon
- Spanish National Cancer Research Centre, Madrid, Spain
- Medicine School, Universidad Autónoma de Madrid
| | - Elena Castro
- Spanish National Cancer Research Centre, Madrid, Spain
| | | | - Ajinkya Revandkar
- Institute of Oncology Research (IOR) and Oncology Institute of Southern Switzerland (IOSI), Bellinzona CH 6500, Switzerland
- Faculty of Biology and Medicine, University of Lausanne (UNIL), Lausanne CH 1011, Switzerland
| | - Andrea Alimonti
- Institute of Oncology Research (IOR) and Oncology Institute of Southern Switzerland (IOSI), Bellinzona CH 6500, Switzerland
- Faculty of Biology and Medicine, University of Lausanne (UNIL), Lausanne CH 1011, Switzerland
| | - Yinan Zhang
- Department of Genetics and Complex Diseases, Harvard School of Public Health, Boston, Massachusetts 02115, USA
| | | | - Gina Lein
- AGIOS Pharmaceuticals, Cambridge, USA
| | | | - Ana R. Cortazar
- CIC bioGUNE, Bizkaia Technology Park, 801 building, 48160, Derio, Spain
| | - Leire Arreal
- CIC bioGUNE, Bizkaia Technology Park, 801 building, 48160, Derio, Spain
| | - Ludmila Prudkin
- Vall d'Hebron Institute of Oncology (VHIO), Universidad Autonoma de Barcelona, Barcelona, Spain
| | - Ianire Astobiza
- CIC bioGUNE, Bizkaia Technology Park, 801 building, 48160, Derio, Spain
| | | | | | | | - Marco Piva
- CIC bioGUNE, Bizkaia Technology Park, 801 building, 48160, Derio, Spain
| | | | | | - Mireia Castillo-Martín
- Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
- Department of Pathology, Fundação Champalimaud, Lisboa, Portugal
| | - Violeta Serra
- Vall d'Hebron Institute of Oncology (VHIO), Universidad Autonoma de Barcelona, Barcelona, Spain
| | - Naiara Beraza
- CIC bioGUNE, Bizkaia Technology Park, 801 building, 48160, Derio, Spain
| | - Antonio Gentilella
- Laboratory of Metabolism and Cancer, Catalan Institute of Oncology, ICO, Bellvitge Biomedical Research Institute, IDIBELL, 08908 Barcelona, Spain
| | - George Thomas
- Laboratory of Metabolism and Cancer, Catalan Institute of Oncology, ICO, Bellvitge Biomedical Research Institute, IDIBELL, 08908 Barcelona, Spain
| | - Mikel Azkargorta
- CIC bioGUNE, Bizkaia Technology Park, 801 building, 48160, Derio, Spain
- Carlos III Networked Proteomics Platform (ProteoRed-ISCIII)
| | - Felix Elortza
- CIC bioGUNE, Bizkaia Technology Park, 801 building, 48160, Derio, Spain
- Carlos III Networked Proteomics Platform (ProteoRed-ISCIII)
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd)
| | - Rosa Farràs
- Centro de Investigación Príncipe Felipe, Eduardo Primo Yúfera 3, 46012 Valencia, Spain
| | - David Olmos
- Spanish National Cancer Research Centre, Madrid, Spain
- CNIO-IBIMA Genitourinary Cancer Unit, Medical Oncology Department, Hospitales Universitarios Virgen de la Victoria y Regional de Málaga
| | - Alejo Efeyan
- Spanish National Cancer Research Centre, Madrid, Spain
| | - Juan Anguita
- CIC bioGUNE, Bizkaia Technology Park, 801 building, 48160, Derio, Spain
- Ikerbasque, Basque foundation for science, Bilbao, Spain
| | - Javier Muñoz
- Spanish National Cancer Research Centre, Madrid, Spain
- Carlos III Networked Proteomics Platform (ProteoRed-ISCIII)
| | - Juan M. Falcón-Pérez
- CIC bioGUNE, Bizkaia Technology Park, 801 building, 48160, Derio, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd)
- Ikerbasque, Basque foundation for science, Bilbao, Spain
| | - Rosa Barrio
- CIC bioGUNE, Bizkaia Technology Park, 801 building, 48160, Derio, Spain
| | - Teresa Macarulla
- CIBERONC
- Vall d'Hebron Institute of Oncology (VHIO), Universidad Autonoma de Barcelona, Barcelona, Spain
| | - Jose M. Mato
- CIC bioGUNE, Bizkaia Technology Park, 801 building, 48160, Derio, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd)
| | - Maria L. Martinez-Chantar
- CIC bioGUNE, Bizkaia Technology Park, 801 building, 48160, Derio, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd)
| | - Carlos Cordon-Cardo
- Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Ana M. Aransay
- CIC bioGUNE, Bizkaia Technology Park, 801 building, 48160, Derio, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd)
| | | | - José Baselga
- Human Oncology & Pathogenesis Program, Memorial Sloan-Kettering Cancer Center, New York, New York, USA
| | - Josep Tabernero
- CIBERONC
- Vall d'Hebron Institute of Oncology (VHIO), Universidad Autonoma de Barcelona, Barcelona, Spain
| | - Paolo Nuciforo
- Vall d'Hebron Institute of Oncology (VHIO), Universidad Autonoma de Barcelona, Barcelona, Spain
| | - Brendan D. Manning
- Department of Genetics and Complex Diseases, Harvard School of Public Health, Boston, Massachusetts 02115, USA
| | | | - Arkaitz Carracedo
- CIC bioGUNE, Bizkaia Technology Park, 801 building, 48160, Derio, Spain
- CIBERONC
- Ikerbasque, Basque foundation for science, Bilbao, Spain
- Biochemistry and Molecular Biology Department, University of the Basque Country (UPV/EHU), Bilbao, Spain
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288
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Ka M, Smith AL, Kim WY. MTOR controls genesis and autophagy of GABAergic interneurons during brain development. Autophagy 2017; 13:1348-1363. [PMID: 28598226 DOI: 10.1080/15548627.2017.1327927] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Interneuron progenitors in the ganglionic eminence of the ventral telencephalon generate most cortical interneurons during brain development. However, the regulatory mechanism of interneuron progenitors remains poorly understood. Here, we show that MTOR (mechanistic target of rapamycin [serine/threonine kinase]) regulates proliferation and macroautophagy/autophagy of interneuron progenitors in the developing ventral telencephalon. To investigate the role of MTOR in interneuron progenitors, we conditionally deleted the Mtor gene in mouse interneuron progenitors and their progeny by using Tg(mI56i-cre,EGFP)1Kc/Dlx5/6-Cre-IRES-EGFP and Nkx2-1-Cre drivers. We found that Mtor deletion markedly reduced the number of interneurons in the cerebral cortex. However, relative positioning of cortical interneurons was normal, suggesting that disruption of progenitor self-renewal caused the decreased number of cortical interneurons in the Mtor-deleted brain. Indeed, Mtor-deleted interneuron progenitors showed abnormal proliferation and cell cycle progression. Additionally, we detected a significant activation of autophagy in Mtor-deleted brain. Our findings suggest that MTOR plays a critical role in the regulation of cortical interneuron number and autophagy in the developing brain.
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Affiliation(s)
- Minhan Ka
- a Department of Developmental Neuroscience , Munroe-Meyer Institute, University of Nebraska Medical Center , Omaha , NE , USA
| | - Amanda L Smith
- a Department of Developmental Neuroscience , Munroe-Meyer Institute, University of Nebraska Medical Center , Omaha , NE , USA
| | - Woo-Yang Kim
- a Department of Developmental Neuroscience , Munroe-Meyer Institute, University of Nebraska Medical Center , Omaha , NE , USA
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289
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Saxton RA, Sabatini DM. mTOR Signaling in Growth, Metabolism, and Disease. Cell 2017; 168:960-976. [PMID: 28283069 DOI: 10.1016/j.cell.2017.02.004] [Citation(s) in RCA: 3790] [Impact Index Per Article: 541.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Revised: 01/22/2017] [Accepted: 02/01/2017] [Indexed: 12/13/2022]
Abstract
The mechanistic target of rapamycin (mTOR) coordinates eukaryotic cell growth and metabolism with environmental inputs, including nutrients and growth factors. Extensive research over the past two decades has established a central role for mTOR in regulating many fundamental cell processes, from protein synthesis to autophagy, and deregulated mTOR signaling is implicated in the progression of cancer and diabetes, as well as the aging process. Here, we review recent advances in our understanding of mTOR function, regulation, and importance in mammalian physiology. We also highlight how the mTOR signaling network contributes to human disease and discuss the current and future prospects for therapeutically targeting mTOR in the clinic.
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Affiliation(s)
- Robert A Saxton
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA; Department of Biology, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Broad Institute of Harvard and Massachusetts Institute of Technology, 415 Main Street, Cambridge, MA 02142, USA
| | - David M Sabatini
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA; Department of Biology, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Broad Institute of Harvard and Massachusetts Institute of Technology, 415 Main Street, Cambridge, MA 02142, USA.
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290
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Hill CE. A view from the ending: Axonal dieback and regeneration following SCI. Neurosci Lett 2017; 652:11-24. [DOI: 10.1016/j.neulet.2016.11.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 10/20/2016] [Accepted: 11/01/2016] [Indexed: 12/22/2022]
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291
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Abstract
Beyond protein synthesis and autophagy, emerging evidence has implicated mTORC1 in regulating protein folding and proteasomal degradation as well, highlighting its prominent role in cellular proteome homeostasis or proteostasis. In addition to growth signals, mTORC1 senses and responds to a wide array of stresses, including energetic/metabolic stress, genotoxic stress, oxidative stress, osmotic stress, ER stress, proteotoxic stress, and psychological stress. Whereas growth signals unanimously stimulate mTORC1, stresses exert complex impacts on mTORC1, most of which are repressive. mTORC1 suppression, as a generic adaptive strategy, empowers cell survival under various stressful conditions. In this essay, we provide an overview of the emerging role of mTORC1 in proteostasis, the distinct molecular mechanisms through which mTORC1 reacts to diverse stresses, and the schemes exploited by cancer cells to circumvent stress-induced mTORC1 suppression. Hence, acting as a stress sensor, mTORC1 intimately couples stresses to cellular proteostasis.
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Affiliation(s)
- Kuo-Hui Su
- Mouse Cancer Genetics Program, Center for Cancer Research, NCI, Frederick, MD 21702, USA
| | - Chengkai Dai
- Mouse Cancer Genetics Program, Center for Cancer Research, NCI, Frederick, MD 21702, USA,Corresponding author: Chengkai Dai,
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292
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Abstract
Beyond protein synthesis and autophagy, emerging evidence has implicated mTORC1 in regulating protein folding and proteasomal degradation as well, highlighting its prominent role in cellular proteome homeostasis or proteostasis. In addition to growth signals, mTORC1 senses and responds to a wide array of stresses, including energetic/metabolic stress, genotoxic stress, oxidative stress, osmotic stress, ER stress, proteotoxic stress, and psychological stress. Whereas growth signals unanimously stimulate mTORC1, stresses exert complex impacts on mTORC1, most of which are repressive. mTORC1 suppression, as a generic adaptive strategy, empowers cell survival under various stressful conditions. In this essay, we provide an overview of the emerging role of mTORC1 in proteostasis, the distinct molecular mechanisms through which mTORC1 reacts to diverse stresses, and the schemes exploited by cancer cells to circumvent stress-induced mTORC1 suppression. Hence, acting as a stress sensor, mTORC1 intimately couples stresses to cellular proteostasis.
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Affiliation(s)
- Kuo-Hui Su
- Mouse Cancer Genetics Program, Center for Cancer Research, NCI, Frederick, MD 21702, USA
| | - Chengkai Dai
- Mouse Cancer Genetics Program, Center for Cancer Research, NCI, Frederick, MD 21702, USA
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293
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Kim HT, Goldberg AL. The deubiquitinating enzyme Usp14 allosterically inhibits multiple proteasomal activities and ubiquitin-independent proteolysis. J Biol Chem 2017; 292:9830-9839. [PMID: 28416611 DOI: 10.1074/jbc.m116.763128] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 03/09/2017] [Indexed: 12/31/2022] Open
Abstract
The proteasome-associated deubiquitinating enzyme Usp14/Ubp6 inhibits protein degradation by catalyzing substrate deubiquitination and by poorly understood allosteric actions. However, upon binding a ubiquitin chain, Usp14 enhances proteasomal degradation by stimulating ATP and peptide degradation. These studies were undertaken to clarify these seemingly opposite regulatory roles of Usp14 and their importance. To learn how the presence of Usp14 on 26S proteasomes influences its different activities, we compared enzymatic and regulatory properties of 26S proteasomes purified from wild-type mouse embryonic fibroblast cells and those lacking Usp14. The proteasomes lacking Usp14 had higher basal peptidase activity than WT 26S, and this activity was stimulated to a greater extent by adenosine 5'-O-(thiotriphosphate) (ATPγS) than with WT particles. These differences were clear even though Usp14 is present on only a minor fraction (30-40%) of the 26S in WT mouse embryonic fibroblast cells. Addition of purified Usp14 to the WT and Usp14-defficient proteasomes reduced both their basal peptidase activity and the stimulation by ATPγS. Usp14 inhibits these processes allosterically because a catalytically inactive Usp14 mutant also inhibited them. Proteasomes lacking Usp14 also exhibited greater deubiquitinating activity by Rpn11 and greater basal ATPase activity than WT particles. ATP hydrolysis by WT proteasomes is activated if they bind a ubiquitinated protein, which is loosely folded. Surprisingly, proteasomes lacking Usp14 could be activated by such proteins even without a ubiquitin chain present. Furthermore, proteasomes lacking Usp14 are much more active in degrading non-ubiquitinated proteins (e.g. Sic1) than WT particles. Thus, without a ubiquitinated substrate present, Usp14 suppresses multiple proteasomal activities, especially basal ATP consumption and degradation of non-ubiquitinated proteins. These allosteric effects thus reduce ATP hydrolysis by inactive proteasomes and nonspecific proteolysis and enhance proteasomal specificity for ubiquitinated proteins.
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Affiliation(s)
- Hyoung Tae Kim
- From the Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115
| | - Alfred L Goldberg
- From the Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115
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294
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Seo AY, Lau PW, Feliciano D, Sengupta P, Gros MAL, Cinquin B, Larabell CA, Lippincott-Schwartz J. AMPK and vacuole-associated Atg14p orchestrate μ-lipophagy for energy production and long-term survival under glucose starvation. eLife 2017; 6. [PMID: 28394250 PMCID: PMC5407857 DOI: 10.7554/elife.21690] [Citation(s) in RCA: 115] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 04/09/2017] [Indexed: 12/22/2022] Open
Abstract
Dietary restriction increases the longevity of many organisms, but the cell signaling and organellar mechanisms underlying this capability are unclear. We demonstrate that to permit long-term survival in response to sudden glucose depletion, yeast cells activate lipid-droplet (LD) consumption through micro-lipophagy (µ-lipophagy), in which fat is metabolized as an alternative energy source. AMP-activated protein kinase (AMPK) activation triggered this pathway, which required Atg14p. More gradual glucose starvation, amino acid deprivation or rapamycin did not trigger µ-lipophagy and failed to provide the needed substitute energy source for long-term survival. During acute glucose restriction, activated AMPK was stabilized from degradation and interacted with Atg14p. This prompted Atg14p redistribution from ER exit sites onto liquid-ordered vacuole membrane domains, initiating µ-lipophagy. Our findings that activated AMPK and Atg14p are required to orchestrate µ-lipophagy for energy production in starved cells is relevant for studies on aging and evolutionary survival strategies of different organisms. DOI:http://dx.doi.org/10.7554/eLife.21690.001
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Affiliation(s)
- Arnold Y Seo
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.,Cell Biology and Metabolism Program, National Institutes of Health, Bethesda, United States
| | - Pick-Wei Lau
- Cell Biology and Metabolism Program, National Institutes of Health, Bethesda, United States
| | - Daniel Feliciano
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.,Cell Biology and Metabolism Program, National Institutes of Health, Bethesda, United States
| | - Prabuddha Sengupta
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.,Cell Biology and Metabolism Program, National Institutes of Health, Bethesda, United States
| | - Mark A Le Gros
- Department of Anatomy, University of California, San Francisco, San Francisco, United States.,Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, United States
| | - Bertrand Cinquin
- Department of Anatomy, University of California, San Francisco, San Francisco, United States
| | - Carolyn A Larabell
- Department of Anatomy, University of California, San Francisco, San Francisco, United States.,Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, United States
| | - Jennifer Lippincott-Schwartz
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.,Cell Biology and Metabolism Program, National Institutes of Health, Bethesda, United States
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295
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Voutsadakis IA. Proteasome expression and activity in cancer and cancer stem cells. Tumour Biol 2017; 39:101042831769224. [DOI: 10.1177/1010428317692248] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023] Open
Abstract
Proteasome is a multi-protein organelle that participates in cellular proteostasis by destroying damaged or short-lived proteins in an organized manner guided by the ubiquitination signal. By being in a central place in the cellular protein complement homeostasis, proteasome is involved in virtually all cell processes including decisions on cell survival or death, cell cycle, and differentiation. These processes are important also in cancer, and thus, the proteasome is an important regulator of carcinogenesis. Cancers include a variety of cells which, according to the cancer stem cell theory, descend from a small percentage of cancer stem cells, alternatively termed tumor-initiating cells. These cells constitute the subsets that have the ability to propagate the whole variety of cancer and repopulate tumors after cytostatic therapies. Proteasome plays a role in cellular processes in cancer stem cells, but it has been found to have a decreased function in them compared to the rest of cancer cells. This article will discuss the transcriptional regulation of proteasome sub-unit proteins in cancer and in particular cancer stem cells and the relationship of the proteasome with the pluripotency that is the defining characteristic of stem cells. Therapeutic opportunities that present from the understanding of the proteasome role will also be discussed.
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Affiliation(s)
- Ioannis A Voutsadakis
- Division of Medical Oncology, Department of Internal Medicine, Sault Area Hospital, Sault Ste. Marie, ON, Canada
- Division of Clinical Sciences, Northern Ontario School of Medicine, Sudbury, ON, Canada
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296
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Andreani C, Bartolacci C, Wijnant K, Crinelli R, Bianchi M, Magnani M, Hysi A, Iezzi M, Amici A, Marchini C. Resveratrol fuels HER2 and ERα-positive breast cancer behaving as proteasome inhibitor. Aging (Albany NY) 2017; 9:508-523. [PMID: 28238967 PMCID: PMC5361678 DOI: 10.18632/aging.101175] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 02/11/2017] [Indexed: 11/25/2022]
Abstract
The phytoestrogen resveratrol has been reported to possess cancer chemo-preventive activity on the basis of its effects on tumor cell lines and xenograft or carcinogen-inducible in vivo models. Here we investigated the effects of resveratrol on spontaneous mammary carcinogenesis using Δ16HER2 mice as HER2+/ERα+ breast cancer model. Instead of inhibiting tumor growth, resveratrol treatment (0.0001% in drinking water; daily intake of 4μg/mouse) shortened tumor latency and enhanced tumor multiplicity in Δ16HER2 mice. This in vivo tumor-promoting effect of resveratrol was associated with up-regulation of Δ16HER2 and down-regulation of ERα protein levels and was recapitulated in vitro by murine (CAM6) and human (BT474) tumor cell lines. Our results demonstrate that resveratrol, acting as a proteasome inhibitor, leads to Δ16HER2 accumulation which favors the formation of Δ16HER2/HER3 heterodimers. The consequential activation of downstream mTORC1/p70S6K/4EBP1 pathway triggers cancer growth and proliferation. This study provides evidence that resveratrol mechanism of action (and hence its effects) depends on the intrinsic molecular properties of the cancer model under investigation, exerting a tumor-promoting effect in luminal B breast cancer subtype models.
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Affiliation(s)
- Cristina Andreani
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, 62032, Italy
| | - Caterina Bartolacci
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, 62032, Italy
| | - Kathleen Wijnant
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, 62032, Italy
| | - Rita Crinelli
- Department of Biomolecular Sciences, Section of Biochemistry and Molecular Biology, University of Urbino “Carlo Bo”, Urbino, 61029, Italy
| | - Marzia Bianchi
- Department of Biomolecular Sciences, Section of Biochemistry and Molecular Biology, University of Urbino “Carlo Bo”, Urbino, 61029, Italy
| | - Mauro Magnani
- Department of Biomolecular Sciences, Section of Biochemistry and Molecular Biology, University of Urbino “Carlo Bo”, Urbino, 61029, Italy
| | - Albana Hysi
- Aging Research Centre, G. d'Annunzio University, Chieti, 66100, Italy
| | - Manuela Iezzi
- Aging Research Centre, G. d'Annunzio University, Chieti, 66100, Italy
| | - Augusto Amici
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, 62032, Italy
| | - Cristina Marchini
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, 62032, Italy
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297
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Liu YH, Weng YP, Lin HY, Tang SW, Chen CJ, Liang CJ, Ku CY, Lin JY. Aqueous extract of Polygonum bistorta modulates proteostasis by ROS-induced ER stress in human hepatoma cells. Sci Rep 2017; 7:41437. [PMID: 28134285 PMCID: PMC5278379 DOI: 10.1038/srep41437] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 12/16/2016] [Indexed: 01/16/2023] Open
Abstract
Hepatocellular carcinoma (HCC) remains the leading cause of cancer mortality with limited therapeutic targets. The endoplasmic reticulum (ER) plays a pivotal role in maintaining proteostasis in normal cells. However, alterations in proteostasis are often found in cancer cells, making it a potential target for therapy. Polygonum bistorta is used in traditional Chinese medicine owing to its anticancer activities, but the molecular and pharmacological mechanisms remain unclear. Using hepatoma cells as a model system, this study demonstrated that P. bistorta aqueous extract (PB) stimulated ER stress by increasing autophagosomes but by blocking degradation, followed by the accumulation of ubiquitinated proteins and cell apoptosis. In addition, an autophagy inhibitor did not enhance ubiquitinated protein accumulation whereas a reactive oxygen species (ROS) scavenger diminished both ubiquitinated protein accumulation and ligand-stimulated epidermal growth factor receptor (EGFR) expression, suggesting that ROS generation by PB may be upstream of PB-triggered cell death. Nevertheless, PB-exerted proteostasis impairment resulted in cytoskeletal changes, impairment of cell adhesion and motility, and inhibition of cell cycle progression. Oral administration of PB delayed tumour growth in a xenograft model without significant body weight loss. These findings indicate that PB may be a potential new alternative or complementary medicine for HCC.
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Affiliation(s)
- Yu-Huei Liu
- Graduate Institute of Integrated Medicine, China Medical University, Taichung, 404, Taiwan.,Department of Medical Genetics and Medical Research, China Medical University Hospital, Taichung, 404, Taiwan
| | - Yui-Ping Weng
- Graduate Institute of Biological Science and Technology, Chung Hwa University of Medical Technology, Tainan, 717, Taiwan.,Department of Biological Science and Technology, Chung Hwa University of Medical Technology, Tainan, 717, Taiwan
| | - Hsuan-Yuan Lin
- Department of Life Science, National Taiwan Normal University, Taipei, 116, Taiwan
| | - Sai-Wen Tang
- Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan
| | - Chao-Jung Chen
- Graduate Institute of Integrated Medicine, China Medical University, Taichung, 404, Taiwan
| | - Chi-Jung Liang
- Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan
| | - Chung-Yu Ku
- Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan
| | - Jung-Yaw Lin
- Department of Life Science, National Taiwan Normal University, Taipei, 116, Taiwan.,Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan
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298
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Continued 26S proteasome dysfunction in mouse brain cortical neurons impairs autophagy and the Keap1-Nrf2 oxidative defence pathway. Cell Death Dis 2017; 8:e2531. [PMID: 28055010 PMCID: PMC5386360 DOI: 10.1038/cddis.2016.443] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 11/18/2016] [Accepted: 11/29/2016] [Indexed: 12/22/2022]
Abstract
The ubiquitin–proteasome system (UPS) and macroautophagy (autophagy) are central to normal proteostasis and interdependent in that autophagy is known to compensate for the UPS to alleviate ensuing proteotoxic stress that impairs cell function. UPS and autophagy dysfunctions are believed to have a major role in the pathomechanisms of neurodegenerative disease. Here we show that continued 26S proteasome dysfunction in mouse brain cortical neurons causes paranuclear accumulation of fragmented dysfunctional mitochondria, associated with earlier recruitment of Parkin and lysine 48-linked ubiquitination of mitochondrial outer membrane (MOM) proteins, including Mitofusin-2. Early events also include phosphorylation of p62/SQSTM1 (p62) and increased optineurin, as well as autophagosomal LC3B and removal of some mitochondria, supporting the induction of selective autophagy. Inhibition of the degradation of ubiquitinated MOM proteins with continued 26S proteasome dysfunction at later stages may impede efficient mitophagy. However, continued 26S proteasome dysfunction also decreases the levels of essential autophagy proteins ATG9 and LC3B, which is characterised by decreases in their gene expression, ultimately leading to impaired autophagy. Intriguingly, serine 351 phosphorylation of p62 did not enhance its binding to Keap1 or stabilise the nuclear factor erythroid 2-related factor 2 (Nrf2) transcription factor in this neuronal context. Nrf2 protein levels were markedly decreased despite transcriptional activation of the Nrf2 gene. Our study reveals novel insights into the interplay between the UPS and autophagy in neurons and is imperative to understanding neurodegenerative disease where long-term proteasome inhibition has been implicated.
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299
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Abstract
Macroautophagy, a major lysosomal degradative pathway for cytoplasmic components, is a process that can be stimulated in response to many stressful situations including cancer treatment. The central autophagic organelle is the autophagosome, a double-membrane-bound vacuole that sequesters cytoplasmic material. The ultimate destiny of the autophagosome is fusion with the lysosomal compartment, where cargo, including proteins, is degraded. Here, we report a method to measure the lysosomal degradation of long-lived proteins along the autophagic pathway.
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Affiliation(s)
- N Dupont
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253, Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - C Leroy
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253, Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - A Hamaï
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253, Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - P Codogno
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253, Université Paris Descartes-Sorbonne Paris Cité, Paris, France.
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300
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Cohen-Kaplan V, Livneh I, Avni N, Cohen-Rosenzweig C, Ciechanover A. The ubiquitin-proteasome system and autophagy: Coordinated and independent activities. Int J Biochem Cell Biol 2016; 79:403-418. [DOI: 10.1016/j.biocel.2016.07.019] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 07/13/2016] [Accepted: 07/18/2016] [Indexed: 01/10/2023]
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