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Lavilla-Puerta M, Latter R, Bellè F, Cervelli T, Galli A, Perata P, Chini A, Flashman E, Giuntoli B. Identification of novel plant cysteine oxidase inhibitors from a yeast chemical genetic screen. J Biol Chem 2023; 299:105366. [PMID: 37863264 PMCID: PMC10692734 DOI: 10.1016/j.jbc.2023.105366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 09/28/2023] [Accepted: 10/11/2023] [Indexed: 10/22/2023] Open
Abstract
Hypoxic responses in plants involve Plant Cysteine Oxidases (PCOs). They catalyze the N-terminal cysteine oxidation of Ethylene Response Factors VII (ERF-VII) in an oxygen-dependent manner, leading to their degradation via the cysteine N-degron pathway (Cys-NDP) in normoxia. In hypoxia, PCO activity drops, leading to the stabilization of ERF-VIIs and subsequent hypoxic gene upregulation. Thus far, no chemicals have been described to specifically inhibit PCO enzymes. In this work, we devised an in vivo pipeline to discover Cys-NDP effector molecules. Budding yeast expressing AtPCO4 and plant-based ERF-VII reporters was deployed to screen a library of natural-like chemical scaffolds and was further combined with an Arabidopsis Cys-NDP reporter line. This strategy allowed us to identify three PCO inhibitors, two of which were shown to affect PCO activity in vitro. Application of these molecules to Arabidopsis seedlings led to an increase in ERF-VII stability, induction of anaerobic gene expression, and improvement of tolerance to anoxia. By combining a high-throughput heterologous platform and the plant model Arabidopsis, our synthetic pipeline provides a versatile system to study how the Cys-NDP is modulated. Its first application here led to the discovery of at least two hypoxia-mimicking molecules with the potential to impact plant tolerance to low oxygen stress.
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Affiliation(s)
| | - Rebecca Latter
- Department of Chemistry, University of Oxford, Oxford, UK
| | | | | | | | | | - Andrea Chini
- Department of Plant Molecular Genetics, Centro Nacional de Biotecnología, CSIC, Madrid, Spain
| | | | - Beatrice Giuntoli
- Plantlab, Center of Plant Sciences, Scuola Superiore Sant'Anna, Pisa, Italy; Biology Department, University of Pisa, Pisa, Italy.
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2
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Jeon JH, Oh TR, Park S, Huh S, Kim JH, Mai BK, Lee JH, Kim SH, Lee MJ. The Antipsychotic Drug Clozapine Suppresses the RGS4 Polyubiquitylation and Proteasomal Degradation Mediated by the Arg/N-Degron Pathway. Neurotherapeutics 2021; 18:1768-1782. [PMID: 33884581 PMCID: PMC8608952 DOI: 10.1007/s13311-021-01039-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/12/2021] [Indexed: 02/04/2023] Open
Abstract
Although diverse antipsychotic drugs have been developed for the treatment of schizophrenia, most of their mechanisms of action remain elusive. Regulator of G-protein signaling 4 (RGS4) has been reported to be linked, both genetically and functionally, with schizophrenia and is a physiological substrate of the arginylation branch of the N-degron pathway (Arg/N-degron pathway). Here, we show that the atypical antipsychotic drug clozapine significantly inhibits proteasomal degradation of RGS4 proteins without affecting their transcriptional expression. In addition, the levels of Arg- and Phe-GFP (artificial substrates of the Arg/N-degron pathway) were significantly elevated by clozapine treatment. In silico computational model suggested that clozapine may interact with active sites of N-recognin E3 ubiquitin ligases. Accordingly, treatment with clozapine resulted in reduced polyubiquitylation of RGS4 and Arg-GFP in the test tube and in cultured cells. Clozapine attenuated the activation of downstream effectors of G protein-coupled receptor signaling, such as MEK1 and ERK1, in HEK293 and SH-SY5Y cells. Furthermore, intraperitoneal injection of clozapine into rats significantly stabilized the endogenous RGS4 protein in the prefrontal cortex. Overall, these results reveal an additional therapeutic mechanism of action of clozapine: this drug posttranslationally inhibits the degradation of Arg/N-degron substrates, including RGS4. These findings imply that modulation of protein post-translational modifications, in particular the Arg/N-degron pathway, may be a novel molecular therapeutic strategy against schizophrenia.
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Affiliation(s)
- Jun Hyoung Jeon
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, 03080, Korea
| | - Tae Rim Oh
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, 03080, Korea
| | - Seoyoung Park
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, 03080, Korea
- Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, 03080, Korea
| | - Sunghoo Huh
- Biomedical Research Institute, Seoul National University Hospital, Seoul, 03080, Korea
| | - Ji Hyeon Kim
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, 03080, Korea
| | - Binh Khanh Mai
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Jung Hoon Lee
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, 03080, Korea
- Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, 03080, Korea
| | - Se Hyun Kim
- Biomedical Research Institute, Seoul National University Hospital, Seoul, 03080, Korea.
- Department of Psychiatry, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, 03080, Korea.
| | - Min Jae Lee
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, 03080, Korea.
- Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, 03080, Korea.
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3
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Leboeuf D, Abakumova T, Prikazchikova T, Rhym L, Anderson DG, Zatsepin TS, Piatkov KI. Downregulation of the Arg/N-degron Pathway Sensitizes Cancer Cells to Chemotherapy In Vivo. Mol Ther 2020; 28:1092-1104. [PMID: 32087767 DOI: 10.1016/j.ymthe.2020.01.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 01/16/2020] [Indexed: 02/07/2023] Open
Abstract
The N-degron pathway is an emerging target for anti-tumor therapies, because of its capacity to positively regulate many hallmarks of cancer, including angiogenesis, cell proliferation, motility, and survival. Thus, inhibition of the N-degron pathway offers the potential to be a highly effective anti-cancer treatment. With the use of a small interfering RNA (siRNA)-mediated approach for selective downregulation of the four Arg/N-degron-dependent ubiquitin ligases, UBR1, UBR2, UBR4, and UBR5, we demonstrated decreased cell migration and proliferation and increased spontaneous apoptosis in cancer cells. Chronic treatment with lipid nanoparticles (LNPs) loaded with siRNA in mice efficiently downregulates the expression of UBR-ubiquitin ligases in the liver without any significant toxic effects but engages the immune system and causes inflammation. However, when used in a lower dose, in combination with a chemotherapeutic drug, downregulation of the Arg/N-degron pathway E3 ligases successfully reduced tumor load by decreasing proliferation and increasing apoptosis in a mouse model of hepatocellular carcinoma, while avoiding the inflammatory response. Our study demonstrates that UBR-ubiquitin ligases of the Arg/N-degron pathway are promising targets for the development of improved therapies for many cancer types.
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Affiliation(s)
| | | | | | - Luke Rhym
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA; Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Daniel G Anderson
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA; Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA; Harvard and MIT Division of Health Science and Technology, Massachusetts Institute of Technology, Cambridge, MA, USA; Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
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4
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Muñoz-Escobar J, Matta-Camacho E, Cho C, Kozlov G, Gehring K. Bound Waters Mediate Binding of Diverse Substrates to a Ubiquitin Ligase. Structure 2017; 25:719-729.e3. [PMID: 28392261 DOI: 10.1016/j.str.2017.03.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 02/03/2017] [Accepted: 03/09/2017] [Indexed: 11/16/2022]
Abstract
The N-end rule pathway controls the half-life of proteins based on their N-terminal residue. Positively charged type 1 N-degrons are recognized by a negatively charged pocket on the Zn finger named the UBR box. Here, we show that the UBR box is rigid, but bound water molecules in the pocket provide the structural plasticity required to bind different positively charged amino acids. Ultra-high-resolution crystal structures of arginine, histidine, and methylated arginine reveal that water molecules mediate the binding of N-degron peptides. Using a high-throughput binding assay and isothermal titration calorimetry, we demonstrate that the UBR box is able to bind methylated arginine and lysine peptides with high affinity and measure the preference for hydrophobic residues in the second position in the N-degron peptide. Finally, we show that the V122L mutation present in Johanson-Blizzard syndrome patients changes the specificity for the second position due to occlusion of the secondary pocket.
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Affiliation(s)
- Juliana Muñoz-Escobar
- Department of Biochemistry, Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montreal, QC H3G 0B1, Canada
| | - Edna Matta-Camacho
- Department of Biochemistry, Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montreal, QC H3G 0B1, Canada
| | - Cordelia Cho
- Department of Biochemistry, Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montreal, QC H3G 0B1, Canada
| | - Guennadi Kozlov
- Department of Biochemistry, Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montreal, QC H3G 0B1, Canada
| | - Kalle Gehring
- Department of Biochemistry, Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montreal, QC H3G 0B1, Canada.
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5
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Kim E, Kim S, Lee JH, Kwon YT, Lee MJ. Ablation of Arg-tRNA-protein transferases results in defective neural tube development. BMB Rep 2017; 49:443-8. [PMID: 27345715 PMCID: PMC5070732 DOI: 10.5483/bmbrep.2016.49.8.087] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Indexed: 12/05/2022] Open
Abstract
The arginylation branch of the N-end rule pathway is a ubiquitin-mediated
proteolytic system in which post-translational conjugation of Arg by
ATE1-encoded Arg-tRNA-protein transferase to N-terminal
Asp, Glu, or oxidized Cys residues generates essential degradation signals.
Here, we characterized the ATE1−/− mice
and identified the essential role of N-terminal arginylation in neural tube
development. ATE1-null mice showed severe intracerebral
hemorrhages and cystic space near the neural tubes. Expression of ATE1 was
prominent in the developing brain and spinal cord, and this pattern overlapped
with the migration path of neural stem cells. The
ATE1−/− brain showed defective
G-protein signaling. Finally, we observed reduced mitosis in
ATE1−/− neuroepithelium and a
significantly higher nitric oxide concentration in the
ATE1−/− brain. Our results strongly
suggest that the crucial role of ATE1 in neural tube development is directly
related to proper turn-over of the RGS4 protein, which participate in the
oxygen-sensing mechanism in the cells. [BMB Reports 2016; 49(8): 443-448]
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Affiliation(s)
- Eunkyoung Kim
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine; Department of Biomedical Sciences, Seoul National University Graduate School, Seoul 03080, Korea
| | - Seonmu Kim
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul 03080, Korea
| | - Jung Hoon Lee
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine; Department of Biomedical Sciences, Seoul National University Graduate School, Seoul 03080, Korea
| | - Yong Tae Kwon
- Department of Biomedical Sciences, Seoul National University Graduate School, Seoul 03080, Korea
| | - Min Jae Lee
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine; Department of Biomedical Sciences, Seoul National University Graduate School; Neuroscience Research Institute, Seoul National University College of Medicine, Seoul 03080, Korea
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6
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Eldeeb MA, Fahlman RP. Phosphorylation Impacts N-end Rule Degradation of the Proteolytically Activated Form of BMX Kinase. J Biol Chem 2016; 291:22757-22768. [PMID: 27601470 DOI: 10.1074/jbc.m116.737387] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 08/24/2016] [Indexed: 11/06/2022] Open
Abstract
Cellular signaling leading to the initiation of apoptosis typically results in the activation of caspases, which in turn leads to the proteolytic generation of protein fragments with new or altered cellular functions. Increasing numbers of reports are demonstrating that the activity of many of these proteolytically activated protein fragments can be attenuated by their selective degradation by the N-end rule pathway. Here we report the first evidence that selective degradation of a caspase product by the N-end rule pathway can be modulated by phosphorylation. We demonstrate that the pro-apoptotic fragment of the bone marrow kinase on chromosome X (BMX) generated by caspase cleavage in the prostate cancer-derived PC3 cell line is metabolically unstable in cells because its N-terminal tryptophan targets it for proteasomal degradation via the N-end rule pathway. In addition, we have demonstrated that phosphorylation of tyrosine 566 relatively inhibits degradation of the C-terminal BMX catalytic fragment, and this phosphorylation is crucial for its pro-apoptotic function. Overall, our results demonstrate that cleaved BMX is a novel N-end rule substrate, and its degradation exhibits a novel interplay between substrate phosphorylation and N-end rule degradation, revealing an increasing complex regulatory network of apoptotic proteolytic signaling cascades.
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Affiliation(s)
| | - Richard P Fahlman
- From the Departments of Biochemistry and .,Oncology, University of Alberta, Edmonton, Alberta T6J 2H7, Canada
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7
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Jiang Y, Lee J, Lee JH, Lee JW, Kim JH, Choi WH, Yoo YD, Cha-Molstad H, Kim BY, Kwon YT, Noh SA, Kim KP, Lee MJ. The arginylation branch of the N-end rule pathway positively regulates cellular autophagic flux and clearance of proteotoxic proteins. Autophagy 2016; 12:2197-2212. [PMID: 27560450 DOI: 10.1080/15548627.2016.1222991] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The N-terminal amino acid of a protein is an essential determinant of ubiquitination and subsequent proteasomal degradation in the N-end rule pathway. Using para-chloroamphetamine (PCA), a specific inhibitor of the arginylation branch of the pathway (Arg/N-end rule pathway), we identified that blocking the Arg/N-end rule pathway significantly impaired the fusion of autophagosomes with lysosomes. Under ER stress, ATE1-encoded Arg-tRNA-protein transferases carry out the N-terminal arginylation of the ER heat shock protein HSPA5 that initially targets cargo proteins, along with SQSTM1, to the autophagosome. At the late stage of autophagy, however, proteasomal degradation of arginylated HSPA5 might function as a critical checkpoint for the proper progression of autophagic flux in the cells. Consistently, the inhibition of the Arg/N-end rule pathway with PCA significantly elevated levels of MAPT and huntingtin aggregates, accompanied by increased numbers of LC3 and SQSTM1 puncta. Cells treated with the Arg/N-end rule inhibitor became more sensitized to proteotoxic stress-induced cytotoxicity. SILAC-based quantitative proteomics also revealed that PCA significantly alters various biological pathways, including cellular responses to stress, nutrient, and DNA damage, which are also closely involved in modulation of autophagic responses. Thus, our results indicate that the Arg/N-end rule pathway may function to actively protect cells from detrimental effects of cellular stresses, including proteotoxic protein accumulation, by positively regulating autophagic flux.
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Affiliation(s)
- Yanxialei Jiang
- a Department of Biochemistry and Molecular Biology , Seoul National University College of Medicine , Seoul , Korea
| | - Jeeyoung Lee
- a Department of Biochemistry and Molecular Biology , Seoul National University College of Medicine , Seoul , Korea.,b Department of Biomedical Sciences , Seoul National University Graduate School , Seoul , Korea
| | - Jung Hoon Lee
- a Department of Biochemistry and Molecular Biology , Seoul National University College of Medicine , Seoul , Korea.,b Department of Biomedical Sciences , Seoul National University Graduate School , Seoul , Korea
| | - Joon Won Lee
- d Department of Applied Chemistry , College of Applied Sciences, Kyung Hee University , Yongin , Korea
| | - Ji Hyeon Kim
- a Department of Biochemistry and Molecular Biology , Seoul National University College of Medicine , Seoul , Korea.,b Department of Biomedical Sciences , Seoul National University Graduate School , Seoul , Korea
| | - Won Hoon Choi
- a Department of Biochemistry and Molecular Biology , Seoul National University College of Medicine , Seoul , Korea.,b Department of Biomedical Sciences , Seoul National University Graduate School , Seoul , Korea
| | - Young Dong Yoo
- b Department of Biomedical Sciences , Seoul National University Graduate School , Seoul , Korea
| | - Hyunjoo Cha-Molstad
- c World Class Institute, Korea Research Institute of Bioscience and Biotechnology , Ochang, Cheongwon , Korea
| | - Bo Yeon Kim
- c World Class Institute, Korea Research Institute of Bioscience and Biotechnology , Ochang, Cheongwon , Korea
| | - Yong Tae Kwon
- b Department of Biomedical Sciences , Seoul National University Graduate School , Seoul , Korea
| | - Sue Ah Noh
- d Department of Applied Chemistry , College of Applied Sciences, Kyung Hee University , Yongin , Korea
| | - Kwang Pyo Kim
- d Department of Applied Chemistry , College of Applied Sciences, Kyung Hee University , Yongin , Korea
| | - Min Jae Lee
- a Department of Biochemistry and Molecular Biology , Seoul National University College of Medicine , Seoul , Korea.,b Department of Biomedical Sciences , Seoul National University Graduate School , Seoul , Korea
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8
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Kim JH, Kim E, Choi WH, Lee J, Lee JH, Lee H, Kim DE, Suh YH, Lee MJ. Inhibitory RNA Aptamers of Tau Oligomerization and Their Neuroprotective Roles against Proteotoxic Stress. Mol Pharm 2016; 13:2039-48. [PMID: 27120117 DOI: 10.1021/acs.molpharmaceut.6b00165] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Tau is a cytosolic protein that functions in the assembly and stabilization of axonal microtubule networks. Its oligomerization may be the rate-limiting step of insoluble aggregate formation, which is a neuropathological hallmark of Alzheimer's disease (AD) and a number of other tauopathies. Recent evidence indicates that soluble tau oligomers are the toxic species for tau-mediated pathology during AD progression. Herein, we describe novel RNA aptamers that target human tau and were identified through an in vitro selection process. These aptamers significantly inhibited the oligomerization propensity of tau both in vitro and in cultured cell models of tauopathy without affecting the half-life of tau. Tauopathy model cells treated with the aptamers were less sensitized to proteotoxic stress induced by tau overexpression. Moreover, the tau aptamers significantly alleviated synthetic tau oligomer-mediated neurotoxicity and dendritic spine loss in primary hippocampal neurons. Thus, our study demonstrates that delaying tau assembly with RNA aptamers is an effective strategy for protecting cells under various neurodegenerative stresses originating from pathogenic tau oligomerization.
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Affiliation(s)
- Ji Hyeon Kim
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine , Seoul 03080, Korea.,Department of Biomedical Sciences, Seoul National University Graduate School , Seoul 03080, Korea
| | - Eunkyoung Kim
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine , Seoul 03080, Korea
| | - Won Hoon Choi
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine , Seoul 03080, Korea.,Department of Biomedical Sciences, Seoul National University Graduate School , Seoul 03080, Korea
| | - Jeeyoung Lee
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine , Seoul 03080, Korea.,Department of Biomedical Sciences, Seoul National University Graduate School , Seoul 03080, Korea
| | - Jung Hoon Lee
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine , Seoul 03080, Korea
| | - Hyojin Lee
- Department of Biomedical Sciences, Seoul National University Graduate School , Seoul 03080, Korea.,Neuroscience Research Institute, Seoul National University College of Medicine , Seoul 03080, Korea
| | - Dong-Eun Kim
- Department of Bioscience and Biotechnology, Konkuk University , Seoul 05029, Korea
| | - Young Ho Suh
- Department of Biomedical Sciences, Seoul National University Graduate School , Seoul 03080, Korea.,Neuroscience Research Institute, Seoul National University College of Medicine , Seoul 03080, Korea
| | - Min Jae Lee
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine , Seoul 03080, Korea.,Department of Biomedical Sciences, Seoul National University Graduate School , Seoul 03080, Korea.,Biomedical Research Institutue, Seoul National University Hospital , Seoul 03080, Korea
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9
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Rabideau AE, Pentelute BL. A d-Amino Acid at the N-Terminus of a Protein Abrogates Its Degradation by the N-End Rule Pathway. ACS CENTRAL SCIENCE 2015; 1:423-430. [PMID: 26807441 PMCID: PMC4711398 DOI: 10.1021/acscentsci.5b00308] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Indexed: 06/05/2023]
Abstract
Eukaryotes have evolved the ubiquitin (Ub)/proteasome system to degrade polypeptides. The Ub/proteasome system is one way that cells regulate cytosolic protein and amino acids levels through the recognition and ubiquitination of a protein's N-terminus via E1, E2, and E3 enzymes. The process by which the N-terminus stimulates intracellular protein degradation is referred to as the N-end rule. Characterization of the N-end rule has been limited to only the natural l-amino acids. Using a cytosolic delivery platform derived from anthrax lethal toxin, we probed the stability of mixed chirality proteins, containing one d-amino acid on the N-terminus of otherwise all l-proteins. In all cases, we observed that one N-terminal d-amino acid stabilized the cargo protein to proteasomal degradation with respect to the N-end rule. We found that since the mixed chirality proteins were not polyubiquitinated, they evaded N-end-mediated proteasomal degradation. Evidently, a subtle change on the N-terminus of a natural protein can enhance its intracellular lifetime.
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10
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Lee JH, Jiang Y, Kwon YT, Lee MJ. Pharmacological Modulation of the N-End Rule Pathway and Its Therapeutic Implications. Trends Pharmacol Sci 2015; 36:782-797. [PMID: 26434644 DOI: 10.1016/j.tips.2015.07.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 07/13/2015] [Accepted: 07/16/2015] [Indexed: 11/26/2022]
Abstract
The N-end rule pathway is a proteolytic system in which single N-terminal amino acids of short-lived substrates determine their metabolic half-lives. Substrates of this pathway have been implicated in the pathogenesis of many diseases, including malignancies, neurodegeneration, and cardiovascular disorders. This review provides a comprehensive overview of current knowledge about the mechanism and functions of the N-end rule pathway. Pharmacological strategies for the modulation of target substrate degradation are also reviewed, with emphasis on their in vivo implications. Given the rapid advances in structural and biochemical understanding of the recognition components (N-recognins) of the N-end rule pathway, small-molecule inhibitors and activating ligands of N-recognins emerge as therapeutic agents with novel mechanisms of action.
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Affiliation(s)
- Jung Hoon Lee
- Department of Biochemistry and Molecular Biology, Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea
| | - Yanxialei Jiang
- Department of Biochemistry and Molecular Biology, Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea
| | - Yong Tae Kwon
- Protein Metabolism Medical Research Center, Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea.
| | - Min Jae Lee
- Department of Biochemistry and Molecular Biology, Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea; Protein Metabolism Medical Research Center, Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea; Neuroscience Research Institute, Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea.
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11
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Kitamura K. Inhibition of the Arg/N-end rule pathway-mediated proteolysis by dipeptide-mimetic molecules. Amino Acids 2015; 48:235-43. [PMID: 26334349 DOI: 10.1007/s00726-015-2083-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 08/21/2015] [Indexed: 11/30/2022]
Abstract
Ubr11 in the fission yeast Schizosaccharomyces pombe is an evolutionarily conserved ubiquitin ligase functioning in the Arg/N-end rule pathway, which promotes degradation of substrate proteins via the proteasome. Ubr11 recognizes the N-degron sequence in substrates. The primary N-degron contains a destabilization-inducing N-terminal amino acid, which is either a basic (type 1) or bulky hydrophobic (type 2) residue. Dipeptides are known to inhibit proteolytic degradation via the Arg/N-end rule pathway. Here, I examined the potency of some amino acid- or dipeptide-related molecules in their inhibition of Ubr11/N-end rule-mediated degradation. An amide form of L-arginine and L-tryptophan had weak inhibitory activity for type 1 and type 2 substrates, respectively, although the unmodified amino acid monomer and its carboxymethylated ester were ineffective. Among the naturally occurring dipeptides tested, Lys-Leu and Tyr-Leu showed potent inhibitory activity, but their effect was transient, especially at submillimolar concentrations. L-arginine-β-naphthylamide (Arg-βNA) showed stronger activity than several dipeptides for type 1 substrates, but all Lys-Leu, Tyr-Leu, and Arg-βNA caused growth retardation. The inhibitory activity of the L-phenylalanine carbobenzoxy-hydrazide for type 2 substrates was not very strong, but it prolonged the action of Tyr-Leu at low concentrations and, importantly, did not interfere with cell growth. Apart from their utility, these dipeptidomimetics provide a clue for understanding the determinants of recognition by Ubr ubiquitin ligase and further designing novel inhibitors of the Arg/N-end rule pathway.
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Affiliation(s)
- Kenji Kitamura
- Center for Gene Science, Hiroshima University, 1-4-2 Kagamiyama, Higashi-Hiroshima, 739-8527, Japan.
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12
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A neurostimulant para-chloroamphetamine inhibits the arginylation branch of the N-end rule pathway. Sci Rep 2014; 4:6344. [PMID: 25212999 PMCID: PMC4161967 DOI: 10.1038/srep06344] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 08/12/2014] [Indexed: 11/08/2022] Open
Abstract
In the arginylation branch of the N-end rule pathway, unacetylated N-terminal destabilizing residues function as essential determinants of protein degradation signals (N-degron). Here, we show that a neurostimulant, para-chloroamphetamine (PCA), specifically inhibits the Arg/N-end rule pathway, delaying the degradation of its artificial and physiological substrates, including regulators of G protein signaling 4 (RGS4), in vitro and in cultured cells. In silico computational analysis indicated that PCA strongly interacts with both UBR box and ClpS box, which bind to type 1 and type 2 N-degrons, respectively. Moreover, intraperitoneal injection of PCA significantly stabilized endogenous RGS4 proteins in the whole mouse brain and, particularly, in the frontal cortex and hippocampus. Consistent with the role of RGS4 in G protein signaling, treatment with PCA impaired the activations of GPCR downstream effectors in N2A cells, phenocopying ATE1-null mutants. In addition, levels of pathological C-terminal fragments of TDP43 bearing N-degrons (Arg208-TDP25) were significantly elevated in the presence of PCA. Thus, our study identifies PCA as a potential tool to understand and modulate various pathological processes regulated by the Arg/N-end rule pathway, including neurodegenerative processes in FTLD-U and ALS.
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13
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Jiang Y, Pore SK, Lee JH, Sriram S, Mai BK, Han DH, Agarwalla P, Zakrzewska A, Kim Y, Banerjee R, Lee SH, Lee MJ. Characterization of mammalian N-degrons and development of heterovalent inhibitors of the N-end rule pathway. Chem Sci 2013. [DOI: 10.1039/c3sc51059j] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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