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Schiavon CR, Shadel GS, Manor U. Impaired Mitochondrial Mobility in Charcot-Marie-Tooth Disease. Front Cell Dev Biol 2021; 9:624823. [PMID: 33598463 PMCID: PMC7882694 DOI: 10.3389/fcell.2021.624823] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Accepted: 01/05/2021] [Indexed: 12/13/2022] Open
Abstract
Charcot-Marie-Tooth (CMT) disease is a progressive, peripheral neuropathy and the most commonly inherited neurological disorder. Clinical manifestations of CMT mutations are typically limited to peripheral neurons, the longest cells in the body. Currently, mutations in at least 80 different genes are associated with CMT and new mutations are regularly being discovered. A large portion of the proteins mutated in axonal CMT have documented roles in mitochondrial mobility, suggesting that organelle trafficking defects may be a common underlying disease mechanism. This review will focus on the potential role of altered mitochondrial mobility in the pathogenesis of axonal CMT, highlighting the conceptional challenges and potential experimental and therapeutic opportunities presented by this "impaired mobility" model of the disease.
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Affiliation(s)
- Cara R. Schiavon
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA, United States
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, United States
| | - Gerald S. Shadel
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, United States
| | - Uri Manor
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA, United States
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Park SR, Kim HJ, Yang SR, Park CH, Lee HY, Hong IS. A novel endogenous damage signal, glycyl tRNA synthetase, activates multiple beneficial functions of mesenchymal stem cells. Cell Death Differ 2018; 25:2023-2036. [PMID: 29666468 DOI: 10.1038/s41418-018-0099-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 02/06/2018] [Accepted: 03/06/2018] [Indexed: 01/06/2023] Open
Abstract
During tissue repair, the injury site releases various bioactive molecules as damage signals to actively recruit stem cells to the damaged region. Despite convincing evidence that mesenchymal stem cells (MSCs) can sense damage signals and promote repair processes, the identity of these signals and how these signals regulate stem cell-mediated tissue repair remain unknown. Glycyl tRNA synthetase (GRS) is a ubiquitously expressed enzyme that catalyzes the first step of protein synthesis in all organisms. In addition to this canonical function, we identified for the first time that GRS is released by damaged tissues or cells in response to various injury signals and may function as a damage signal that activates the proliferative, differentiation, and migratory potential of MSCs, possibly through its identified receptor, cadherin-6 (CDH-6). Binding between GRS and CDH-6 activates survival signals, such as those of the PI3K/Akt and/or FAK/ERK1/2 pathways. More importantly, we also found that MSCs stimulated with GRS show significantly improved homing and differentiation potential and subsequent in vivo therapeutic effects, in a liver fibrosis animal model. Collectively, our findings provide compelling evidence for a novel function of GRS in enhancing the multiple beneficial functions of stem cells via a non-canonical mechanism as a damage signal.
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Affiliation(s)
- Se-Ra Park
- Laboratory of Stem Cell Research, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon, 406-840, Republic of Korea.,Department of Molecular Medicine, School of Medicine, Gachon University, Incheon, 406-840, Republic of Korea
| | - Hyun-Jin Kim
- Laboratory of Stem Cell Research, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon, 406-840, Republic of Korea.,Department of Molecular Medicine, School of Medicine, Gachon University, Incheon, 406-840, Republic of Korea
| | - Se-Ran Yang
- Department of Thoracic and Cardiovascular Surgery, Kangwon National University, Chuncheon, South Korea
| | - Chan Hum Park
- Department of Otolaryngology-Head and Neck Surgery, Chuncheon Sacred Heart Hospital, Hallym University College of Medicine, Chuncheon, South Korea
| | - Hwa-Yong Lee
- Department of Biomedical Science, Jungwon University, 85 Goesan-eup, Munmu-ro, Goesan-gun, 367-700, Republic of Korea.
| | - In-Sun Hong
- Laboratory of Stem Cell Research, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon, 406-840, Republic of Korea. .,Department of Molecular Medicine, School of Medicine, Gachon University, Incheon, 406-840, Republic of Korea.
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Qin X, Hao Z, Tian Q, Zhang Z, Zhou C, Xie W. Cocrystal structures of glycyl-tRNA synthetase in complex with tRNA suggest multiple conformational states in glycylation. J Biol Chem 2014; 289:20359-69. [PMID: 24898252 PMCID: PMC4106348 DOI: 10.1074/jbc.m114.557249] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 05/31/2014] [Indexed: 12/16/2022] Open
Abstract
Aminoacyl-tRNA synthetases are an ancient enzyme family that specifically charges tRNA molecules with cognate amino acids for protein synthesis. Glycyl-tRNA synthetase (GlyRS) is one of the most intriguing aminoacyl-tRNA synthetases due to its divergent quaternary structure and abnormal charging properties. In the past decade, mutations of human GlyRS (hGlyRS) were also found to be associated with Charcot-Marie-Tooth disease. However, the mechanisms of traditional and alternative functions of hGlyRS are poorly understood due to a lack of studies at the molecular basis. In this study we report crystal structures of wild type and mutant hGlyRS in complex with tRNA and with small substrates and describe the molecular details of enzymatic recognition of the key tRNA identity elements in the acceptor stem and the anticodon loop. The cocrystal structures suggest that insertions 1 and 3 work together with the active site in a cooperative manner to facilitate efficient substrate binding. Both the enzyme and tRNA molecules undergo significant conformational changes during glycylation. A working model of multiple conformations for hGlyRS catalysis is proposed based on the crystallographic and biochemical studies. This study provides insights into the catalytic pathway of hGlyRS and may also contribute to our understanding of Charcot-Marie-Tooth disease.
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Affiliation(s)
- Xiangjing Qin
- From the Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, School of Life Sciences, The Sun Yat-Sen University, Guangzhou 510275, China, Center for Cellular and Structural Biology, The Sun Yat-Sen University, 132 E. Circle, University City, Guangzhou 510006, China, and
| | - Zhitai Hao
- From the Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, School of Life Sciences, The Sun Yat-Sen University, Guangzhou 510275, China, Center for Cellular and Structural Biology, The Sun Yat-Sen University, 132 E. Circle, University City, Guangzhou 510006, China, and
| | - Qingnan Tian
- From the Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, School of Life Sciences, The Sun Yat-Sen University, Guangzhou 510275, China, Center for Cellular and Structural Biology, The Sun Yat-Sen University, 132 E. Circle, University City, Guangzhou 510006, China, and
| | - Zhemin Zhang
- From the Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, School of Life Sciences, The Sun Yat-Sen University, Guangzhou 510275, China, Center for Cellular and Structural Biology, The Sun Yat-Sen University, 132 E. Circle, University City, Guangzhou 510006, China, and
| | - Chun Zhou
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10065
| | - Wei Xie
- From the Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, School of Life Sciences, The Sun Yat-Sen University, Guangzhou 510275, China, Center for Cellular and Structural Biology, The Sun Yat-Sen University, 132 E. Circle, University City, Guangzhou 510006, China, and
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Charcot-Marie-Tooth-linked mutant GARS is toxic to peripheral neurons independent of wild-type GARS levels. PLoS Genet 2011; 7:e1002399. [PMID: 22144914 PMCID: PMC3228828 DOI: 10.1371/journal.pgen.1002399] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Accepted: 10/13/2011] [Indexed: 01/19/2023] Open
Abstract
Charcot-Marie-Tooth disease type 2D (CMT2D) is a dominantly inherited peripheral neuropathy caused by missense mutations in the glycyl-tRNA synthetase gene (GARS). In addition to GARS, mutations in three other tRNA synthetase genes cause similar neuropathies, although the underlying mechanisms are not fully understood. To address this, we generated transgenic mice that ubiquitously over-express wild-type GARS and crossed them to two dominant mouse models of CMT2D to distinguish loss-of-function and gain-of-function mechanisms. Over-expression of wild-type GARS does not improve the neuropathy phenotype in heterozygous Gars mutant mice, as determined by histological, functional, and behavioral tests. Transgenic GARS is able to rescue a pathological point mutation as a homozygote or in complementation tests with a Gars null allele, demonstrating the functionality of the transgene and revealing a recessive loss-of-function component of the point mutation. Missense mutations as transgene-rescued homozygotes or compound heterozygotes have a more severe neuropathy than heterozygotes, indicating that increased dosage of the disease-causing alleles results in a more severe neurological phenotype, even in the presence of a wild-type transgene. We conclude that, although missense mutations of Gars may cause some loss of function, the dominant neuropathy phenotype observed in mice is caused by a dose-dependent gain of function that is not mitigated by over-expression of functional wild-type protein.
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Guo RT, Chong YE, Guo M, Yang XL. Crystal structures and biochemical analyses suggest a unique mechanism and role for human glycyl-tRNA synthetase in Ap4A homeostasis. J Biol Chem 2009; 284:28968-76. [PMID: 19710017 PMCID: PMC2781443 DOI: 10.1074/jbc.m109.030692] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Aminoacyl-tRNA synthetases catalyze the attachment of amino acids to their cognate tRNAs for protein synthesis. However, the aminoacylation reaction can be diverted to produce diadenosine tetraphosphate (Ap4A), a universal pleiotropic signaling molecule needed for cell regulation pathways. The only known mechanism for Ap4A production by a tRNA synthetase is through the aminoacylation reaction intermediate aminoacyl-AMP, thus making Ap4A synthesis amino acid-dependent. Here, we demonstrate a new mechanism for Ap4A synthesis. Crystal structures and biochemical analyses show that human glycyl-tRNA synthetase (GlyRS) produces Ap4A by direct condensation of two ATPs, independent of glycine concentration. Interestingly, whereas the first ATP-binding pocket is conserved for all class II tRNA synthetases, the second ATP pocket is formed by an insertion domain that is unique to GlyRS, suggesting that GlyRS is the only tRNA synthetase catalyzing direct Ap4A synthesis. A special role for GlyRS in Ap4A homeostasis is proposed.
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Affiliation(s)
- Rey-Ting Guo
- From the Department of Molecular Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037
| | - Yeeting E. Chong
- From the Department of Molecular Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037
| | - Min Guo
- From the Department of Molecular Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037
| | - Xiang-Lei Yang
- From the Department of Molecular Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, To whom correspondence should be addressed: Scripps Research Inst., BCC110, North Torrey Pines Rd., La Jolla, CA 92037. Tel.: 858-784-8976; Fax: 858-784-7250; E-mail:
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Abstract
Aminoacylation of transfer RNAs establishes the rules of the genetic code. The reactions are catalyzed by an ancient group of 20 enzymes (one for each amino acid) known as aminoacyl tRNA synthetases (AARSs). Surprisingly, the etiology of specific diseases-including cancer, neuronal pathologies, autoimmune disorders, and disrupted metabolic conditions-is connected to specific aminoacyl tRNA synthetases. These connections include heritable mutations in the genes for tRNA synthetases that are causally linked to disease, with both dominant and recessive disease-causing mutations being annotated. Because some disease-causing mutations do not affect aminoacylation activity or apparent enzyme stability, the mutations are believed to affect functions that are distinct from aminoacylation. Examples include enzymes that are secreted as procytokines that, after activation, operate in pathways connected to the immune system or angiogenesis. In addition, within cells, synthetases form multiprotein complexes with each other or with other regulatory factors and in that way control diverse signaling pathways. Although much has been uncovered in recent years, many novel functions, disease connections, and interpathway connections of tRNA synthetases have yet to be worked out.
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Xie W, Nangle LA, Zhang W, Schimmel P, Yang XL. Long-range structural effects of a Charcot-Marie-Tooth disease-causing mutation in human glycyl-tRNA synthetase. Proc Natl Acad Sci U S A 2007; 104:9976-81. [PMID: 17545306 PMCID: PMC1891255 DOI: 10.1073/pnas.0703908104] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Functional expansion of specific tRNA synthetases in higher organisms is well documented. These additional functions may explain why dominant mutations in glycyl-tRNA synthetase (GlyRS) and tyrosyl-tRNA synthetase cause Charcot-Marie-Tooth (CMT) disease, the most common heritable disease of the peripheral nervous system. At least 10 disease-causing mutant alleles of GlyRS have been annotated. These mutations scatter broadly across the primary sequence and have no apparent unifying connection. Here we report the structure of wild type and a CMT-causing mutant (G526R) of homodimeric human GlyRS. The mutation is at the site for synthesis of glycyl-adenylate, but the rest of the two structures are closely similar. Significantly, the mutant form diffracts to a higher resolution and has a greater dimer interface. The extra dimer interactions are located approximately 30 A away from the G526R mutation. Direct experiments confirm the tighter dimer interaction of the G526R protein. The results suggest the possible importance of subtle, long-range structural effects of CMT-causing mutations at the dimer interface. From analysis of a third crystal, an appended motif, found in higher eukaryote GlyRSs, seems not to have a role in these long-range effects.
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Affiliation(s)
- Wei Xie
- The Skaggs Institute for Chemical Biology and Department of Molecular Biology, The Scripps Research Institute, BCC-379, 10550 North Torrey Pines Road, La Jolla, CA 92037
| | - Leslie A. Nangle
- The Skaggs Institute for Chemical Biology and Department of Molecular Biology, The Scripps Research Institute, BCC-379, 10550 North Torrey Pines Road, La Jolla, CA 92037
| | - Wei Zhang
- The Skaggs Institute for Chemical Biology and Department of Molecular Biology, The Scripps Research Institute, BCC-379, 10550 North Torrey Pines Road, La Jolla, CA 92037
| | - Paul Schimmel
- The Skaggs Institute for Chemical Biology and Department of Molecular Biology, The Scripps Research Institute, BCC-379, 10550 North Torrey Pines Road, La Jolla, CA 92037
- *To whom correspondence may be addressed. E-mail: or
| | - Xiang-Lei Yang
- The Skaggs Institute for Chemical Biology and Department of Molecular Biology, The Scripps Research Institute, BCC-379, 10550 North Torrey Pines Road, La Jolla, CA 92037
- *To whom correspondence may be addressed. E-mail: or
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Cader MZ, Ren J, James PA, Bird LE, Talbot K, Stammers DK. Crystal structure of human wildtype and S581L-mutant glycyl-tRNA synthetase, an enzyme underlying distal spinal muscular atrophy. FEBS Lett 2007; 581:2959-64. [PMID: 17544401 DOI: 10.1016/j.febslet.2007.05.046] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2007] [Revised: 05/15/2007] [Accepted: 05/16/2007] [Indexed: 11/30/2022]
Abstract
Dominant mutations in the ubiquitous enzyme glycyl-tRNA synthetase (GlyRS), including S581L, lead to motor nerve degeneration. We have determined crystal structures of wildtype and S581L-mutant human GlyRS. The S581L mutation is approximately 50A from the active site, and yet gives reduced aminoacylation activity. The overall structures of wildtype and S581L-GlyRS, including the active site, are very similar. However, residues 567-575 of the anticodon-binding domain shift position and in turn could indirectly affect glycine binding via the tRNA or alternatively inhibit conformational changes. Reduced enzyme activity may underlie neuronal degeneration, although a dominant-negative effect is more likely in this autosomal dominant disorder.
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Affiliation(s)
- Muhammed Z Cader
- Henry Wellcome Building for Gene Function, MRC Functional Genetics Unit, University of Oxford, South Parks Road, Oxford OX1 3QX, United Kingdom
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