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Lv X, Zhang R, Li S, Jin X. tRNA Modifications and Dysregulation: Implications for Brain Diseases. Brain Sci 2024; 14:633. [PMID: 39061374 PMCID: PMC11274612 DOI: 10.3390/brainsci14070633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 06/05/2024] [Accepted: 06/12/2024] [Indexed: 07/28/2024] Open
Abstract
Transfer RNAs (tRNAs) are well-known for their essential function in protein synthesis. Recent research has revealed a diverse range of chemical modifications that tRNAs undergo, which are crucial for various cellular processes. These modifications are necessary for the precise and efficient translation of proteins and also play important roles in gene expression regulation and cellular stress response. This review examines the role of tRNA modifications and dysregulation in the pathophysiology of various brain diseases, including epilepsy, stroke, neurodevelopmental disorders, brain tumors, Alzheimer's disease, and Parkinson's disease. Through a comprehensive analysis of existing research, our study aims to elucidate the intricate relationship between tRNA dysregulation and brain diseases. This underscores the critical need for ongoing exploration in this field and provides valuable insights that could facilitate the development of innovative diagnostic tools and therapeutic approaches, ultimately improving outcomes for individuals grappling with complex neurological conditions.
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Affiliation(s)
- Xinxin Lv
- School of Medicine, Nankai University, Tianjin 300071, China; (X.L.); (S.L.)
| | - Ruorui Zhang
- Dana and David Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, CA 90089, USA;
| | - Shanshan Li
- School of Medicine, Nankai University, Tianjin 300071, China; (X.L.); (S.L.)
| | - Xin Jin
- School of Medicine, Nankai University, Tianjin 300071, China; (X.L.); (S.L.)
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2
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Zhao T, Fan J, Abu-Zaid A, Burley SK, Zheng XS. Nuclear mTOR Signaling Orchestrates Transcriptional Programs Underlying Cellular Growth and Metabolism. Cells 2024; 13:781. [PMID: 38727317 PMCID: PMC11083943 DOI: 10.3390/cells13090781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 04/26/2024] [Accepted: 05/01/2024] [Indexed: 05/13/2024] Open
Abstract
mTOR is a central regulator of cell growth and metabolism in response to mitogenic and nutrient signals. Notably, mTOR is not only found in the cytoplasm but also in the nucleus. This review highlights direct involvement of nuclear mTOR in regulating transcription factors, orchestrating epigenetic modifications, and facilitating chromatin remodeling. These effects intricately modulate gene expression programs associated with growth and metabolic processes. Furthermore, the review underscores the importance of nuclear mTOR in mediating the interplay between metabolism and epigenetic modifications. By integrating its functions in nutrient signaling and gene expression related to growth and metabolism, nuclear mTOR emerges as a central hub governing cellular homeostasis, malignant transformation, and cancer progression. Better understanding of nuclear mTOR signaling has the potential to lead to novel therapies against cancer and other growth-related diseases.
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Affiliation(s)
- Tinghan Zhao
- Rutgers Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Jialin Fan
- Rutgers Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Ahmed Abu-Zaid
- Rutgers Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Stephen K. Burley
- Rutgers Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
- RCSB Protein Data Bank and Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, 174 Frelinghuysen Road, Piscataway, NJ 08854, USA
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, 174 Frelinghuysen Road, Piscataway, NJ 08854, USA
| | - X.F. Steven Zheng
- Rutgers Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
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3
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Meuten TK, Dean GA, Thamm DH. Review: The PI3K-AKT-mTOR signal transduction pathway in canine cancer. Vet Pathol 2024; 61:339-356. [PMID: 37905509 DOI: 10.1177/03009858231207021] [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] [Indexed: 11/02/2023]
Abstract
Tumors in dogs and humans share many similar molecular and genetic features, incentivizing a better understanding of canine neoplasms not only for the purpose of treating companion animals, but also to facilitate research of spontaneously developing tumors with similar biologic behavior and treatment approaches in an immunologically competent animal model. Multiple tumor types of both species have similar dysregulation of signal transduction through phosphatidylinositol 3-kinase (PI3K), protein kinase B (PKB; AKT), and mechanistic target of rapamycin (mTOR), collectively known as the PI3K-AKT-mTOR pathway. This review aims to delineate the pertinent aspects of the PI3K-AKT-mTOR signaling pathway in health and in tumor development. It will then present a synopsis of current understanding of PI3K-AKT-mTOR signaling in important canine cancers and advancements in targeted inhibitors of this pathway.
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Chen Y, Han L, Dufour CR, Alfonso A, Giguère V. Canonical and Nuclear mTOR Specify Distinct Transcriptional Programs in Androgen-Dependent Prostate Cancer Cells. Mol Cancer Res 2024; 22:113-124. [PMID: 37889103 DOI: 10.1158/1541-7786.mcr-23-0087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 09/21/2023] [Accepted: 10/24/2023] [Indexed: 10/28/2023]
Abstract
mTOR is a serine/threonine kinase that controls prostate cancer cell growth in part by regulating gene programs associated with metabolic and cell proliferation pathways. mTOR-mediated control of gene expression can be achieved via phosphorylation of transcription factors, leading to changes in their cellular localization and activities. mTOR also directly associates with chromatin in complex with transcriptional regulators, including the androgen receptor (AR). Nuclear mTOR (nmTOR) has been previously shown to act as a transcriptional integrator of the androgen signaling pathway in association with the chromatin remodeling machinery, AR, and FOXA1. However, the contribution of cytoplasmic mTOR (cmTOR) and nmTOR and the role played by FOXA1 in this process remains to be explored. Herein, we engineered cells expressing mTOR tagged with nuclear localization and export signals dictating mTOR localization. Transcriptome profiling in AR-positive prostate cancer cells revealed that nmTOR generally downregulates a subset of the androgen response pathway independently of its kinase activity, while cmTOR upregulates a cell cycle-related gene signature in a kinase-dependent manner. Biochemical and genome-wide transcriptomic analyses demonstrate that nmTOR functionally interacts with AR and FOXA1. Ablation of FOXA1 reprograms the nmTOR cistrome and transcriptome of androgen responsive prostate cancer cells. This works highlights a transcriptional regulatory pathway in which direct interactions between nmTOR, AR and FOXA1 dictate a combinatorial role for these factors in the control of specific gene programs in prostate cancer cells. IMPLICATIONS The finding that canonical and nuclear mTOR signaling pathways control distinct gene programs opens therapeutic opportunities to modulate mTOR activity in prostate cancer cells.
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Affiliation(s)
- Yonghong Chen
- Goodman Cancer Institute, McGill University, Montréal, Québec, Canada
- Department of Biochemistry, Faculty of Medicine and Health Sciences, McGill University, Montréal, Québec, Canada
| | - Lingwei Han
- Goodman Cancer Institute, McGill University, Montréal, Québec, Canada
- Department of Biochemistry, Faculty of Medicine and Health Sciences, McGill University, Montréal, Québec, Canada
| | | | - Anthony Alfonso
- Goodman Cancer Institute, McGill University, Montréal, Québec, Canada
- Department of Biochemistry, Faculty of Medicine and Health Sciences, McGill University, Montréal, Québec, Canada
| | - Vincent Giguère
- Goodman Cancer Institute, McGill University, Montréal, Québec, Canada
- Department of Biochemistry, Faculty of Medicine and Health Sciences, McGill University, Montréal, Québec, Canada
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Shi Y, Feng Y, Wang Q, Dong G, Xia W, Jiang F. The Role of tRNA-Centered Translational Regulatory Mechanisms in Cancer. Cancers (Basel) 2023; 16:77. [PMID: 38201505 PMCID: PMC10778012 DOI: 10.3390/cancers16010077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 12/14/2023] [Accepted: 12/19/2023] [Indexed: 01/12/2024] Open
Abstract
Cancer is a leading cause of morbidity and mortality worldwide. While numerous factors have been identified as contributing to the development of malignancy, our understanding of the mechanisms involved remains limited. Early cancer detection and the development of effective treatments are therefore critical areas of research. One class of molecules that play a crucial role in the transmission of genetic information are transfer RNAs (tRNAs), which are the most abundant RNA molecules in the human transcriptome. Dysregulated synthesis of tRNAs directly results in translation disorders and diseases, including cancer. Moreover, various types of tRNA modifications and the enzymes responsible for these modifications have been implicated in tumor biology. Furthermore, alterations in tRNA modification can impact tRNA stability, and impaired stability can prompt the cleavage of tRNAs into smaller fragments known as tRNA fragments (tRFs). Initially believed to be random byproducts lacking any physiological function, tRFs have now been redefined as non-coding RNA molecules with distinct roles in regulating RNA stability, translation, target gene expression, and other biological processes. In this review, we present recent findings on translational regulatory models centered around tRNAs in tumors, providing a deeper understanding of tumorigenesis and suggesting new directions for cancer treatment.
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Affiliation(s)
- Yuanjian Shi
- Department of Thoracic Surgery, Nanjing Medical University Affiliated Cancer Hospital & Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research, Nanjing 211166, China; (Y.S.); (Y.F.); (Q.W.); (G.D.)
- Jiangsu Key Laboratory of Molecular and Translational Cancer Research, Cancer Institute of Jiangsu Province, Nanjing 210009, China
- The Fourth Clinical College, Nanjing Medical University, Nanjing 210029, China
| | - Yipeng Feng
- Department of Thoracic Surgery, Nanjing Medical University Affiliated Cancer Hospital & Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research, Nanjing 211166, China; (Y.S.); (Y.F.); (Q.W.); (G.D.)
- Jiangsu Key Laboratory of Molecular and Translational Cancer Research, Cancer Institute of Jiangsu Province, Nanjing 210009, China
- The Fourth Clinical College, Nanjing Medical University, Nanjing 210029, China
| | - Qinglin Wang
- Department of Thoracic Surgery, Nanjing Medical University Affiliated Cancer Hospital & Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research, Nanjing 211166, China; (Y.S.); (Y.F.); (Q.W.); (G.D.)
- Jiangsu Key Laboratory of Molecular and Translational Cancer Research, Cancer Institute of Jiangsu Province, Nanjing 210009, China
- The Fourth Clinical College, Nanjing Medical University, Nanjing 210029, China
| | - Gaochao Dong
- Department of Thoracic Surgery, Nanjing Medical University Affiliated Cancer Hospital & Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research, Nanjing 211166, China; (Y.S.); (Y.F.); (Q.W.); (G.D.)
- Jiangsu Key Laboratory of Molecular and Translational Cancer Research, Cancer Institute of Jiangsu Province, Nanjing 210009, China
| | - Wenjie Xia
- Department of Thoracic Surgery, Nanjing Medical University Affiliated Cancer Hospital & Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research, Nanjing 211166, China; (Y.S.); (Y.F.); (Q.W.); (G.D.)
- Jiangsu Key Laboratory of Molecular and Translational Cancer Research, Cancer Institute of Jiangsu Province, Nanjing 210009, China
| | - Feng Jiang
- Department of Thoracic Surgery, Nanjing Medical University Affiliated Cancer Hospital & Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research, Nanjing 211166, China; (Y.S.); (Y.F.); (Q.W.); (G.D.)
- Jiangsu Key Laboratory of Molecular and Translational Cancer Research, Cancer Institute of Jiangsu Province, Nanjing 210009, China
- The Fourth Clinical College, Nanjing Medical University, Nanjing 210029, China
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Tsang CK, Mi Q, Su G, Hwa Lee G, Xie X, D'Arcangelo G, Huang L, Steven Zheng XF. Maf1 is an intrinsic suppressor against spontaneous neural repair and functional recovery after ischemic stroke. J Adv Res 2023; 51:73-90. [PMID: 36402285 PMCID: PMC10491990 DOI: 10.1016/j.jare.2022.11.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/28/2022] [Accepted: 11/13/2022] [Indexed: 11/18/2022] Open
Abstract
INTRODUCTION Spontaneous recovery after CNS injury is often very limited and incomplete, leaving most stroke patients with permanent disability. Maf1 is known as a key growth suppressor in proliferating cells. However, its role in neuronal cells after stroke remains unclear. OBJECTIVE We aimed to investigate the mechanistic role of Maf1 in spontaneous neural repair and evaluated the therapeutic effect of targeting Maf1 on stroke recovery. METHODS We used mouse primary neurons to determine the signaling mechanism of Maf1, and the cleavage-under-targets-and-tagmentation-sequencing to map the whole-genome promoter binding sites of Maf1 in isolated mature cortical neurons. Photothrombotic stroke model was used to determine the therapeutic effect on neural repair and functional recovery by AAV-mediated Maf1 knockdown. RESULTS We found that Maf1 mediates mTOR signaling to regulate RNA polymerase III (Pol III)-dependent rRNA and tRNA transcription in mouse cortical neurons. mTOR regulates neuronal Maf1 phosphorylation and subcellular localization. Maf1 knockdown significantly increases Pol III transcription, neurite outgrowth and dendritic spine formation in neurons. Conversely, Maf1 overexpression suppresses such activities. In response to photothrombotic stroke in mice, Maf1 expression is increased and accumulates in the nucleus of neurons in the peripheral region of infarcted cortex, which is the key region for neural remodeling and repair during spontaneous recovery. Intriguingly, Maf1 knockdown in the peri-infarct cortex significantly enhances neural plasticity and functional recovery. Mechanistically, Maf1 not only interacts with the promoters and represses Pol III-transcribed genes, but also those of CREB-associated genes that are critical for promoting plasticity during neurodevelopment and neural repair. CONCLUSION These findings indicate Maf1 as an intrinsic neural repair suppressor against regenerative capability of mature CNS neurons, and suggest that Maf1 is a potential therapeutic target for enhancing functional recovery after ischemic stroke and other CNS injuries.
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Affiliation(s)
- Chi Kwan Tsang
- Clinical Neuroscience Institute, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China; Rutgers Cancer Institute of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08903, USA.
| | - Qiongjie Mi
- Clinical Neuroscience Institute, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China; Department of Neurology, The First Clinical Medical School of Jinan University, Guangzhou, China
| | - Guangpu Su
- Clinical Neuroscience Institute, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China; Department of Neurology, The First Clinical Medical School of Jinan University, Guangzhou, China
| | - Gum Hwa Lee
- Department of Cell Biology and Neuroscience, Rutgers, the State University of New Jersey, Piscataway, NJ 08854, USA
| | - Xuemin Xie
- Clinical Neuroscience Institute, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China; Department of Neurology, The First Clinical Medical School of Jinan University, Guangzhou, China
| | - Gabriella D'Arcangelo
- Department of Cell Biology and Neuroscience, Rutgers, the State University of New Jersey, Piscataway, NJ 08854, USA
| | - Li'an Huang
- Clinical Neuroscience Institute, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China; Department of Neurology, The First Clinical Medical School of Jinan University, Guangzhou, China; Department of Neurology and Stroke Center, The First Affiliated Hospital, Jinan University Guangzhou, Guangdong, China.
| | - X F Steven Zheng
- Rutgers Cancer Institute of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08903, USA.
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Nguyen T, Mills JC, Cho CJ. The coordinated management of ribosome and translation during injury and regeneration. Front Cell Dev Biol 2023; 11:1186638. [PMID: 37427381 PMCID: PMC10325863 DOI: 10.3389/fcell.2023.1186638] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 06/06/2023] [Indexed: 07/11/2023] Open
Abstract
Diverse acute and chronic injuries induce damage responses in the gastrointestinal (GI) system, and numerous cell types in the gastrointestinal tract demonstrate remarkable resilience, adaptability, and regenerative capacity in response to stress. Metaplasias, such as columnar and secretory cell metaplasia, are well-known adaptations that these cells make, the majority of which are epidemiologically associated with an elevated cancer risk. On a number of fronts, it is now being investigated how cells respond to injury at the tissue level, where diverse cell types that differ in proliferation capacity and differentiation state cooperate and compete with one another to participate in regeneration. In addition, the cascades or series of molecular responses that cells show are just beginning to be understood. Notably, the ribosome, a ribonucleoprotein complex that is essential for translation on the endoplasmic reticulum (ER) and in the cytoplasm, is recognized as the central organelle during this process. The highly regulated management of ribosomes as key translational machinery, and their platform, rough endoplasmic reticulum, are not only essential for maintaining differentiated cell identity, but also for achieving successful cell regeneration after injury. This review will cover in depth how ribosomes, the endoplasmic reticulum, and translation are regulated and managed in response to injury (e.g., paligenosis), as well as why this is essential for the proper adaptation of a cell to stress. For this, we will first discuss how multiple gastrointestinal organs respond to stress through metaplasia. Next, we will cover how ribosomes are generated, maintained, and degraded, in addition to the factors that govern translation. Finally, we will investigate how ribosomes and translation machinery are dynamically regulated in response to injury. Our increased understanding of this overlooked cell fate decision mechanism will facilitate the discovery of novel therapeutic targets for gastrointestinal tract tumors, focusing on ribosomes and translation machinery.
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Affiliation(s)
- Thanh Nguyen
- Department of Medicine, Baylor College of Medicine, Houston, TX, United States
| | - Jason C. Mills
- Department of Medicine, Baylor College of Medicine, Houston, TX, United States
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, United States
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, United States
| | - Charles J. Cho
- Department of Medicine, Baylor College of Medicine, Houston, TX, United States
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8
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Gutiérrez-Santiago F, Navarro F. Transcription by the Three RNA Polymerases under the Control of the TOR Signaling Pathway in Saccharomyces cerevisiae. Biomolecules 2023; 13:biom13040642. [PMID: 37189389 DOI: 10.3390/biom13040642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/30/2023] [Accepted: 04/02/2023] [Indexed: 04/05/2023] Open
Abstract
Ribosomes are the basis for protein production, whose biogenesis is essential for cells to drive growth and proliferation. Ribosome biogenesis is highly regulated in accordance with cellular energy status and stress signals. In eukaryotic cells, response to stress signals and the production of newly-synthesized ribosomes require elements to be transcribed by the three RNA polymerases (RNA pols). Thus, cells need the tight coordination of RNA pols to adjust adequate components production for ribosome biogenesis which depends on environmental cues. This complex coordination probably occurs through a signaling pathway that links nutrient availability with transcription. Several pieces of evidence strongly support that the Target of Rapamycin (TOR) pathway, conserved among eukaryotes, influences the transcription of RNA pols through different mechanisms to ensure proper ribosome components production. This review summarizes the connection between TOR and regulatory elements for the transcription of each RNA pol in the budding yeast Saccharomyces cerevisiae. It also focuses on how TOR regulates transcription depending on external cues. Finally, it discusses the simultaneous coordination of the three RNA pols through common factors regulated by TOR and summarizes the most important similarities and differences between S. cerevisiae and mammals.
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Affiliation(s)
- Francisco Gutiérrez-Santiago
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Paraje de las Lagunillas, s/n, E-23071 Jaén, Spain
| | - Francisco Navarro
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Paraje de las Lagunillas, s/n, E-23071 Jaén, Spain
- Centro de Estudios Avanzados en Aceite de Oliva y Olivar, Universidad de Jaén, Paraje de las Lagunillas, s/n, E-23071 Jaén, Spain
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Ni C, Buszczak M. The homeostatic regulation of ribosome biogenesis. Semin Cell Dev Biol 2023; 136:13-26. [PMID: 35440410 PMCID: PMC9569395 DOI: 10.1016/j.semcdb.2022.03.043] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/30/2022] [Accepted: 03/31/2022] [Indexed: 12/22/2022]
Abstract
The continued integrity of biological systems depends on a balance between interdependent elements at the molecular, cellular, and organismal levels. This is particularly true for the generation of ribosomes, which influence almost every aspect of cell and organismal biology. Ribosome biogenesis (RiBi) is an energetically demanding process that involves all three RNA polymerases, numerous RNA processing factors, chaperones, and the coordinated expression of 79-80 ribosomal proteins (r-proteins). Work over the last several decades has revealed that the dynamic regulation of ribosome production represents a major mechanism by which cells maintain homeostasis in response to changing environmental conditions and acute stress. More recent studies suggest that cells and tissues within multicellular organisms exhibit dramatically different levels of ribosome production and protein synthesis, marked by the differential expression of RiBi factors. Thus, distinct bottlenecks in the RiBi process, downstream of rRNA transcription, may exist within different cell populations of multicellular organisms during development and in adulthood. This review will focus on our current understanding of the mechanisms that link the complex molecular process of ribosome biogenesis with cellular and organismal physiology. We will discuss diverse topics including how different steps in the RiBi process are coordinated with one another, how MYC and mTOR impact RiBi, and how RiBi levels change between stem cells and their differentiated progeny. In turn, we will also review how regulated changes in ribosome production itself can feedback to influence cell fate and function.
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Affiliation(s)
- Chunyang Ni
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA
| | - Michael Buszczak
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA.
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10
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H’ng CH, Khaladkar A, Rosello-Diez A. Look who's TORking: mTOR-mediated integration of cell status and external signals during limb development and endochondral bone growth. Front Cell Dev Biol 2023; 11:1153473. [PMID: 37152288 PMCID: PMC10154674 DOI: 10.3389/fcell.2023.1153473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Accepted: 04/03/2023] [Indexed: 05/09/2023] Open
Abstract
The balance of cell proliferation and size is key for the control of organ development and repair. Moreover, this balance has to be coordinated within tissues and between tissues to achieve robustness in the organ's pattern and size. The tetrapod limb has been used to study these topics during development and repair, and several conserved pathways have emerged. Among them, mechanistic target of rapamycin (mTOR) signaling, despite being active in several cell types and developmental stages, is one of the least understood in limb development, perhaps because of its multiple potential roles and interactions with other pathways. In the body of this review, we have collated and integrated what is known about the role of mTOR signaling in three aspects of tetrapod limb development: 1) limb outgrowth; 2) chondrocyte differentiation after mesenchymal condensation and 3) endochondral ossification-driven longitudinal bone growth. We conclude that, given its ability to interact with the most common signaling pathways, its presence in multiple cell types, and its ability to influence cell proliferation, size and differentiation, the mTOR pathway is a critical integrator of external stimuli and internal status, coordinating developmental transitions as complex as those taking place during limb development. This suggests that the study of the signaling pathways and transcription factors involved in limb patterning, morphogenesis and growth could benefit from probing the interaction of these pathways with mTOR components.
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Affiliation(s)
- Chee Ho H’ng
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, Australia
| | - Ashwini Khaladkar
- Department of Biochemistry, Central University of Hyderabad, Hyderabad, India
| | - Alberto Rosello-Diez
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, Australia
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
- *Correspondence: Alberto Rosello-Diez, ,
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Abstract
tRNAs are key adaptor molecules that decipher the genetic code during translation of mRNAs in protein synthesis. In contrast to the traditional view of tRNAs as ubiquitously expressed housekeeping molecules, awareness is now growing that tRNA-encoding genes display tissue-specific and cell type-specific patterns of expression, and that tRNA gene expression and function are both dynamically regulated by post-transcriptional RNA modifications. Moreover, dysregulation of tRNAs, mediated by alterations in either their abundance or function, can have deleterious consequences that contribute to several distinct human diseases, including neurological disorders and cancer. Accumulating evidence shows that reprogramming of mRNA translation through altered tRNA activity can drive pathological processes in a codon-dependent manner. This Review considers the emerging evidence in support of the precise control of functional tRNA levels as an important regulatory mechanism that coordinates mRNA translation and protein expression in physiological cell homeostasis, and highlights key examples of human diseases that are linked directly to tRNA dysregulation.
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Affiliation(s)
- Esteban A Orellana
- Stem Cell Program, Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Elisabeth Siegal
- Stem Cell Program, Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, USA
| | - Richard I Gregory
- Stem Cell Program, Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, USA.
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA.
- Harvard Stem Cell Institute, Harvard University, Cambridge, MA, USA.
- Harvard Initiative for RNA Medicine, Harvard University, Boston, MA, USA.
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12
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Jiang W, Ou Z, Zhu Q, Zai H. RagC GTPase regulates mTOR to promote chemoresistance in senescence-like HepG2 cells. Front Physiol 2022; 13:949737. [PMID: 36267578 PMCID: PMC9577253 DOI: 10.3389/fphys.2022.949737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 09/20/2022] [Indexed: 11/23/2022] Open
Abstract
Radiotherapy and chemotherapy can arrest cancer cells in a senescence-like state, which can lead to therapy resistance and cancer relapse. mTOR is hyperactivated in senescent cells but the mechanisms remain unclear. In this study, we examine the roles of several mTOR-regulated GTPases in senescence-like liver cancer cells and the mechanisms in drug resistance. We show that although RagC, Rheb, Rab1A, Rab5 and Arf1 GTPases were required for optimal mTOR activation in proliferating HepG2 cells, only RagC and Rheb are required in the senescence-like counterparts. Consistently, the drug resistance of the senescence-like HepG2 can be reduced by knocking down RagC and Rheb but not the other GTPases. Autophagic and lysosomal activity were increased in senescence-like cells; pharmacological inhibition of autophagy-lysosome decreased mTOR activity and preferentially sensitized senescence-like HepG2 cells to chemotherapy drugs including trametinib, cisplatin, and doxorubicin. In liver cancer patients, expression of RagC and Rheb but not other GTPases examined was associated with unfavorable prognosis. Our study therefore has defined a key role of Rag-Rheb GTPase in mediating mTOR activation and drug resistance in senescence-like HepG2 cells, which could have important implications in developing second-line treatments for liver cancer patients.
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Affiliation(s)
- Wei Jiang
- Department of General Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Central South University, Changsha, Hunan, China
| | - Zhenglin Ou
- Department of General Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Central South University, Changsha, Hunan, China
| | - Qin Zhu
- Department of General Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Central South University, Changsha, Hunan, China
| | - Hongyan Zai
- Department of General Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Central South University, Changsha, Hunan, China
- *Correspondence: Hongyan Zai,
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13
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Wu H, Wei M, Li Y, Ma Q, Zhang H. Research Progress on the Regulation Mechanism of Key Signal Pathways Affecting the Prognosis of Glioma. Front Mol Neurosci 2022; 15. [DOI: https:/doi.org/10.3389/fnmol.2022.910543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2023] Open
Abstract
As is known to all, glioma, a global difficult problem, has a high malignant degree, high recurrence rate and poor prognosis. We analyzed and summarized signal pathway of the Hippo/YAP, PI3K/AKT/mTOR, miRNA, WNT/β-catenin, Notch, Hedgehog, TGF-β, TCS/mTORC1 signal pathway, JAK/STAT signal pathway, MAPK signaling pathway, the relationship between BBB and signal pathways and the mechanism of key enzymes in glioma. It is concluded that Yap1 inhibitor may become an effective target for the treatment of glioma in the near future through efforts of generation after generation. Inhibiting PI3K/Akt/mTOR, Shh, Wnt/β-Catenin, and HIF-1α can reduce the migration ability and drug resistance of tumor cells to improve the prognosis of glioma. The analysis shows that Notch1 and Sox2 have a positive feedback regulation mechanism, and Notch4 predicts the malignant degree of glioma. In this way, notch cannot only be treated for glioma stem cells in clinic, but also be used as an evaluation index to evaluate the prognosis, and provide an exploratory attempt for the direction of glioma treatment. MiRNA plays an important role in diagnosis, and in the treatment of glioma, VPS25, KCNQ1OT1, KB-1460A1.5, and CKAP4 are promising prognostic indicators and a potential therapeutic targets for glioma, meanwhile, Rheb is also a potent activator of Signaling cross-talk etc. It is believed that these studies will help us to have a deeper understanding of glioma, so that we will find new and better treatment schemes to gradually conquer the problem of glioma.
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14
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Wu H, Wei M, Li Y, Ma Q, Zhang H. Research Progress on the Regulation Mechanism of Key Signal Pathways Affecting the Prognosis of Glioma. Front Mol Neurosci 2022; 15:910543. [PMID: 35935338 PMCID: PMC9354928 DOI: 10.3389/fnmol.2022.910543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 05/30/2022] [Indexed: 11/17/2022] Open
Abstract
As is known to all, glioma, a global difficult problem, has a high malignant degree, high recurrence rate and poor prognosis. We analyzed and summarized signal pathway of the Hippo/YAP, PI3K/AKT/mTOR, miRNA, WNT/β-catenin, Notch, Hedgehog, TGF-β, TCS/mTORC1 signal pathway, JAK/STAT signal pathway, MAPK signaling pathway, the relationship between BBB and signal pathways and the mechanism of key enzymes in glioma. It is concluded that Yap1 inhibitor may become an effective target for the treatment of glioma in the near future through efforts of generation after generation. Inhibiting PI3K/Akt/mTOR, Shh, Wnt/β-Catenin, and HIF-1α can reduce the migration ability and drug resistance of tumor cells to improve the prognosis of glioma. The analysis shows that Notch1 and Sox2 have a positive feedback regulation mechanism, and Notch4 predicts the malignant degree of glioma. In this way, notch cannot only be treated for glioma stem cells in clinic, but also be used as an evaluation index to evaluate the prognosis, and provide an exploratory attempt for the direction of glioma treatment. MiRNA plays an important role in diagnosis, and in the treatment of glioma, VPS25, KCNQ1OT1, KB-1460A1.5, and CKAP4 are promising prognostic indicators and a potential therapeutic targets for glioma, meanwhile, Rheb is also a potent activator of Signaling cross-talk etc. It is believed that these studies will help us to have a deeper understanding of glioma, so that we will find new and better treatment schemes to gradually conquer the problem of glioma.
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Affiliation(s)
- Hao Wu
- Graduate School of Dalian Medical University, Dalian, China
- Department of Neurosurgery, The Yangzhou School of Clinical Medicine of Dalian Medical University, Dalian, China
| | - Min Wei
- Graduate School of Dalian Medical University, Dalian, China
- Department of Neurosurgery, The Yangzhou School of Clinical Medicine of Dalian Medical University, Dalian, China
| | - Yuping Li
- Department of Neurosurgery, The Yangzhou School of Clinical Medicine of Dalian Medical University, Dalian, China
| | - Qiang Ma
- Department of Neurosurgery, The Yangzhou School of Clinical Medicine of Dalian Medical University, Dalian, China
| | - Hengzhu Zhang
- Graduate School of Dalian Medical University, Dalian, China
- Department of Neurosurgery, The Yangzhou School of Clinical Medicine of Dalian Medical University, Dalian, China
- *Correspondence: Hengzhu Zhang,
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15
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Temaj G, Saha S, Dragusha S, Ejupi V, Buttari B, Profumo E, Beqa L, Saso L. Ribosomopathies and cancer: pharmacological implications. Expert Rev Clin Pharmacol 2022; 15:729-746. [PMID: 35787725 DOI: 10.1080/17512433.2022.2098110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION The ribosome is a ribonucleoprotein organelle responsible for protein synthesis, and its biogenesis is a highly coordinated process that involves many macromolecular components. Any acquired or inherited impairment in ribosome biogenesis or ribosomopathies is associated with the development of different cancers and rare genetic diseases. Interference with multiple steps of protein synthesis has been shown to promote tumor cell death. AREAS COVERED We discuss the current insights about impaired ribosome biogenesis and their secondary consequences on protein synthesis, transcriptional and translational responses, proteotoxic stress, and other metabolic pathways associated with cancer and rare diseases. Studies investigating the modulation of different therapeutic chemical entities targeting cancer in in vitro and in vivo models have also been detailed. EXPERT OPINION Despite the association between inherited mutations affecting ribosome biogenesis and cancer biology, the development of therapeutics targeting the essential cellular machinery has only started to emerge. New chemical entities should be designed to modulate different checkpoints (translating oncoproteins, dysregulation of specific ribosome-assembly machinery, ribosomal stress, and rewiring ribosomal functions). Although safe and effective therapies are lacking, consideration should also be given to using existing drugs alone or in combination for long-term safety, with known risks for feasibility in clinical trials and synergistic effects.
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Affiliation(s)
| | - Sarmistha Saha
- Department of Cardiovascular, Endocrine-metabolic Diseases, and Aging, Italian National Institute of Health, Rome, Italy
| | | | - Valon Ejupi
- College UBT, Faculty of Pharmacy, Prishtina, Kosovo
| | - Brigitta Buttari
- Department of Cardiovascular, Endocrine-metabolic Diseases, and Aging, Italian National Institute of Health, Rome, Italy
| | - Elisabetta Profumo
- Department of Cardiovascular, Endocrine-metabolic Diseases, and Aging, Italian National Institute of Health, Rome, Italy
| | - Lule Beqa
- College UBT, Faculty of Pharmacy, Prishtina, Kosovo
| | - Luciano Saso
- Department of Physiology and Pharmacology "Vittorio Erspamer", Sapienza University of Rome, Italy
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16
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Kovalski JR, Kuzuoglu‐Ozturk D, Ruggero D. Protein synthesis control in cancer: selectivity and therapeutic targeting. EMBO J 2022; 41:e109823. [PMID: 35315941 PMCID: PMC9016353 DOI: 10.15252/embj.2021109823] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 12/10/2021] [Accepted: 12/16/2021] [Indexed: 11/09/2022] Open
Abstract
Translational control of mRNAs is a point of convergence for many oncogenic signals through which cancer cells tune protein expression in tumorigenesis. Cancer cells rely on translational control to appropriately adapt to limited resources while maintaining cell growth and survival, which creates a selective therapeutic window compared to non-transformed cells. In this review, we first discuss how cancer cells modulate the translational machinery to rapidly and selectively synthesize proteins in response to internal oncogenic demands and external factors in the tumor microenvironment. We highlight the clinical potential of compounds that target different translation factors as anti-cancer therapies. Next, we detail how RNA sequence and structural elements interface with the translational machinery and RNA-binding proteins to coordinate the translation of specific pro-survival and pro-growth programs. Finally, we provide an overview of the current and emerging technologies that can be used to illuminate the mechanisms of selective translational control in cancer cells as well as within the microenvironment.
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Affiliation(s)
- Joanna R Kovalski
- Helen Diller Family Comprehensive Cancer CenterUniversity of California, San FranciscoSan FranciscoCAUSA
- Department of UrologyUniversity of California, San FranciscoSan FranciscoCAUSA
| | - Duygu Kuzuoglu‐Ozturk
- Helen Diller Family Comprehensive Cancer CenterUniversity of California, San FranciscoSan FranciscoCAUSA
- Department of UrologyUniversity of California, San FranciscoSan FranciscoCAUSA
| | - Davide Ruggero
- Helen Diller Family Comprehensive Cancer CenterUniversity of California, San FranciscoSan FranciscoCAUSA
- Department of UrologyUniversity of California, San FranciscoSan FranciscoCAUSA
- Department of Cellular and Molecular PharmacologyUniversity of California, San FranciscoSan FranciscoCAUSA
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17
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Ball CB, Parida M, Li M, Spector BM, Suarez GA, Meier JL, Price DH. Human Cytomegalovirus Infection Elicits Global Changes in Host Transcription by RNA Polymerases I, II, and III. Viruses 2022; 14:v14040779. [PMID: 35458509 PMCID: PMC9026722 DOI: 10.3390/v14040779] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 03/29/2022] [Accepted: 03/30/2022] [Indexed: 12/29/2022] Open
Abstract
How human cytomegalovirus (HCMV) infection impacts the transcription of the host genome remains incompletely understood. Here, we examine the global consequences of infection of primary human foreskin fibroblasts (HFFs) on transcription by RNA polymerase I, II, and III over the course of a lytic infection using PRO-Seq. The expected rapid induction of innate immune response genes is observed with specific subsets of genes exhibiting dissimilar expression kinetics. We find minimal effects on Pol II initiation, but increased rates of the release of paused Pol II into productive elongation are detected by 24 h postinfection and pronounced at late times postinfection. Pol I transcription increases during infection and we provide evidence for a potential Pol I elongation control mechanism. Pol III transcription of tRNA genes is dramatically altered, with many induced and some repressed. All effects are partially dependent on viral genome replication, suggesting a link to viral mRNA levels and/or a viral early–late or late gene product. Changes in tRNA transcription are connected to distinct alterations in the chromatin state around tRNA genes, which were probed with high-resolution DFF-ChIP. Additionally, evidence is provided that the Pol III PIC stably contacts an upstream −1 nucleosome. Finally, we compared and contrasted our HCMV data with results from published experiments with HSV-1, EBV, KSHV, and MHV68. We report disparate effects on Pol II transcription and potentially similar effects on Pol III transcription.
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Affiliation(s)
- Christopher B. Ball
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA 52242, USA; (C.B.B.); (M.P.); (B.M.S.); (G.A.S.)
| | - Mrutyunjaya Parida
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA 52242, USA; (C.B.B.); (M.P.); (B.M.S.); (G.A.S.)
| | - Ming Li
- Departments of Internal Medicine and Epidemiology, University of Iowa and Iowa City Veterans Affairs Health Care System, Iowa City, IA 52242, USA; (M.L.); (J.L.M.)
| | - Benjamin M. Spector
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA 52242, USA; (C.B.B.); (M.P.); (B.M.S.); (G.A.S.)
| | - Gustavo A. Suarez
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA 52242, USA; (C.B.B.); (M.P.); (B.M.S.); (G.A.S.)
| | - Jeffery L. Meier
- Departments of Internal Medicine and Epidemiology, University of Iowa and Iowa City Veterans Affairs Health Care System, Iowa City, IA 52242, USA; (M.L.); (J.L.M.)
| | - David H. Price
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA 52242, USA; (C.B.B.); (M.P.); (B.M.S.); (G.A.S.)
- Correspondence:
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18
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Surya A, Sarinay-Cenik E. Cell autonomous and non-autonomous consequences of deviations in translation machinery on organism growth and the connecting signalling pathways. Open Biol 2022; 12:210308. [PMID: 35472285 PMCID: PMC9042575 DOI: 10.1098/rsob.210308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 03/31/2022] [Indexed: 01/09/2023] Open
Abstract
Translation machinery is responsible for the production of cellular proteins; thus, cells devote the majority of their resources to ribosome biogenesis and protein synthesis. Single-copy loss of function in the translation machinery components results in rare ribosomopathy disorders, such as Diamond-Blackfan anaemia in humans and similar developmental defects in various model organisms. Somatic copy number alterations of translation machinery components are also observed in specific tumours. The organism-wide response to haploinsufficient loss-of-function mutations in ribosomal proteins or translation machinery components is complex: variations in translation machinery lead to reduced ribosome biogenesis, protein translation and altered protein homeostasis and cellular signalling pathways. Cells are affected both autonomously and non-autonomously by changes in translation machinery or ribosome biogenesis through cell-cell interactions and secreted hormones. We first briefly introduce the model organisms where mutants or knockdowns of protein synthesis and ribosome biogenesis are characterized. Next, we specifically describe observations in Caenorhabditis elegans and Drosophila melanogaster, where insufficient protein synthesis in a subset of cells triggers cell non-autonomous growth or apoptosis responses that affect nearby cells and tissues. We then cover the characterized signalling pathways that interact with ribosome biogenesis/protein synthesis machinery with an emphasis on their respective functions during organism development.
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Affiliation(s)
- Agustian Surya
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, USA
| | - Elif Sarinay-Cenik
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, USA
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19
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Blayney J, Geary J, Chrisp R, Violet J, Barratt L, Tavukçu L, Paine K, Vaistij FE, Graham IA, Denby KJ, White RJ. Impact on Arabidopsis growth and stress resistance of depleting the Maf1 repressor of RNA polymerase III. Gene 2022; 815:146130. [PMID: 35017035 DOI: 10.1016/j.gene.2021.146130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 12/07/2021] [Accepted: 12/15/2021] [Indexed: 11/30/2022]
Abstract
Maf1 is a transcription factor that is conserved in sequence and structure between yeasts, animals and plants. Its principal molecular function is also well conserved, being to bind and repress RNA polymerase (pol) III, thereby inhibiting synthesis of tRNAs and other noncoding RNAs. Restrictions on tRNA production and hence protein synthesis can provide a mechanism to preserve resources under conditions that are suboptimal for growth. Accordingly, Maf1 is found in some organisms to influence growth and/or stress survival. Because of their sessile nature, plants are especially vulnerable to environmental changes and molecular adaptations that enhance growth under benign circumstances can increase sensitivity to external challenges. We tested if Maf1 depletion in the model plant Arabidopsis affects growth, pathogen resistance and tolerance of drought or soil salinity, a common physiological challenge that imposes both osmotic and ionic stress. We find that disruption of the Maf1 gene or RNAi-mediated depletion of its transcript is well-tolerated and confers a modest growth advantage without compromising resistance to common biotic and abiotic challenges.
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Affiliation(s)
- Joseph Blayney
- Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - James Geary
- Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - Ruby Chrisp
- Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - Joseph Violet
- Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - Liam Barratt
- Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - Laçin Tavukçu
- Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - Katherine Paine
- Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - Fabián E Vaistij
- Centre for Novel Agricultural Products (CNAP), Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - Ian A Graham
- Centre for Novel Agricultural Products (CNAP), Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - Katherine J Denby
- Centre for Novel Agricultural Products (CNAP), Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - Robert J White
- Department of Biology, University of York, Heslington, York YO10 5DD, UK.
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20
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de Melo Madureira ÁN, de Oliveira JRS, de Menezes Lima VL. The Role of IL-6 Released During Exercise to Insulin Sensitivity and Muscle Hypertrophy. Mini Rev Med Chem 2022; 22:2419-2428. [PMID: 35264090 DOI: 10.2174/1389557522666220309161245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 11/25/2021] [Accepted: 01/27/2022] [Indexed: 11/22/2022]
Abstract
Interleukin-6 (IL-6) influences both inflammatory response and anti-inflammatory processes. This cytokine can be released by the exercising skeletal muscle, which characterizes it as a myokine. Unlike what is observed in inflammation, IL-6 produced by skeletal muscle is not preceded by the release of other pro-inflammatory cytokines, but is seems to be dependent on the lactate produced during exercise, thus causing different effects from those of seen in inflammatory state. After binding to its receptor, myokine IL-6 activates the PI3K-Akt pathway. One consequence of this upregulation is the potentiation of insulin signaling, which enhances insulin sensitivity. IL-6 increases GLUT-4 vesicle mobilization to muscle cell periphery, increasing the glucose transport into the cell, and also glycogen synthesis. Muscle glycogen provides energy for the ATP resynthesis, and regulates Ca2+ release by the sarcoplasmic reticulum, influencing muscle contraction, and, hence, muscle function by multiple pathways. Another implication for the upregulation of PI3K-Akt pathway is the activation of mTORC1, which regulates mRNA translational efficiency by regulating translation machinery, and translational capacity by inducing ribosomal biogenesis. Thus, IL-6 may contribute for skeletal muscle hypertrophy and function by increasing contractile protein synthesis.
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Affiliation(s)
- Álvaro Nóbrega de Melo Madureira
- Laboratory of Lipids and Application of Biomolecules to Prevalent and Neglected Diseases (LAB-DPN), Department of Biochemistry, Federal University of Pernambuco (UFPE)
| | - João Ricardhis Saturnino de Oliveira
- Laboratory of Lipids and Application of Biomolecules to Prevalent and Neglected Diseases (LAB-DPN), Department of Biochemistry, Federal University of Pernambuco (UFPE)
| | - Vera Lúcia de Menezes Lima
- Laboratory of Lipids and Application of Biomolecules to Prevalent and Neglected Diseases (LAB-DPN), Department of Biochemistry, Federal University of Pernambuco (UFPE)
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21
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Zhong Y, Zhou X, Guan KL, Zhang J. Rheb regulates nuclear mTORC1 activity independent of farnesylation. Cell Chem Biol 2022; 29:1037-1045.e4. [PMID: 35294906 DOI: 10.1016/j.chembiol.2022.02.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 10/26/2021] [Accepted: 02/10/2022] [Indexed: 11/26/2022]
Abstract
The small GTPase Ras homolog enriched in brain (Rheb) plays a critical role in activating the mechanistic target of rapamycin complex 1 (mTORC1), a signaling hub that regulates various cellular functions. We recently observed nuclear mTORC1 activity, raising an intriguing question as to how Rheb, which is known to be farnesylated and localized to intracellular membranes, regulates nuclear mTORC1. In this study, we found that active Rheb is present in the nucleus and required for nuclear mTORC1 activity. We showed that inhibition of farnesyltransferase reduced cytosolic, but not nuclear, mTORC1 activity. Furthermore, a farnesylation-deficient Rheb mutant, with preferential nuclear localization and specific lysosome tethering, enables nuclear and cytosolic mTORC1 activities, respectively. These data suggest that non-farnesylated Rheb is capable of interacting with and activating mTORC1, providing mechanistic insights into the molecular functioning of Rheb as well as regulation of the recently observed, active pool of nuclear mTORC1.
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Affiliation(s)
- Yanghao Zhong
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA; Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA, USA
| | - Xin Zhou
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA
| | - Kun-Liang Guan
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA; Moores Cancer Center, University of California, San Diego, La Jolla, CA, USA
| | - Jin Zhang
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA; Moores Cancer Center, University of California, San Diego, La Jolla, CA, USA; Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA; Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA.
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22
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Szaflarski W, Leśniczak-Staszak M, Sowiński M, Ojha S, Aulas A, Dave D, Malla S, Anderson P, Ivanov P, Lyons SM. Early rRNA processing is a stress-dependent regulatory event whose inhibition maintains nucleolar integrity. Nucleic Acids Res 2022; 50:1033-1051. [PMID: 34928368 PMCID: PMC8789083 DOI: 10.1093/nar/gkab1231] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 11/24/2021] [Accepted: 12/02/2021] [Indexed: 01/20/2023] Open
Abstract
The production of ribosomes is an energy-intensive process owing to the intricacy of these massive macromolecular machines. Each human ribosome contains 80 ribosomal proteins and four non-coding RNAs. Accurate assembly requires precise regulation of protein and RNA subunits. In response to stress, the integrated stress response (ISR) rapidly inhibits global translation. How rRNA is coordinately regulated with the rapid inhibition of ribosomal protein synthesis is not known. Here, we show that stress specifically inhibits the first step of rRNA processing. Unprocessed rRNA is stored within the nucleolus, and when stress resolves, it re-enters the ribosome biogenesis pathway. Retention of unprocessed rRNA within the nucleolus aids in the maintenance of this organelle. This response is independent of the ISR or inhibition of cellular translation but is independently regulated. Failure to coordinately control ribosomal protein translation and rRNA production results in nucleolar fragmentation. Our study unveils how the rapid translational shut-off in response to stress coordinates with rRNA synthesis production to maintain nucleolar integrity.
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Affiliation(s)
- Witold Szaflarski
- Department of Histology and Embryology, Poznan University of Medical Sciences, Poznań, Poland
| | - Marta Leśniczak-Staszak
- Department of Histology and Embryology, Poznan University of Medical Sciences, Poznań, Poland
| | - Mateusz Sowiński
- Department of Histology and Embryology, Poznan University of Medical Sciences, Poznań, Poland
| | - Sandeep Ojha
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
- The Genome Science Institute, Boston University School of Medicine, Boston, MA, USA
| | - Anaïs Aulas
- Predictive Oncology Laboratory, Cancer Research Center of Marseille (CRCM), Inserm U1068, CNRS UMR7258, Institut Paoli-Calmettes, Aix Marseille Université, Marseille, France
| | - Dhwani Dave
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital, Boston, MA, USA
| | - Sulochan Malla
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
- The Genome Science Institute, Boston University School of Medicine, Boston, MA, USA
| | - Paul Anderson
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital, Boston, MA, USA
- Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Pavel Ivanov
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital, Boston, MA, USA
- Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Shawn M Lyons
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
- The Genome Science Institute, Boston University School of Medicine, Boston, MA, USA
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23
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tRNA biogenesis and specific aminoacyl-tRNA synthetases regulate senescence stability under the control of mTOR. PLoS Genet 2021; 17:e1009953. [PMID: 34928935 PMCID: PMC8722728 DOI: 10.1371/journal.pgen.1009953] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 01/03/2022] [Accepted: 11/17/2021] [Indexed: 12/11/2022] Open
Abstract
Oncogenes or chemotherapy treatments trigger the induction of suppressive pathways such as apoptosis or senescence. Senescence was initially defined as a definitive arrest of cell proliferation but recent results have shown that this mechanism is also associated with cancer progression and chemotherapy resistance. Senescence is therefore much more heterogeneous than initially thought. How this response varies is not really understood, it has been proposed that its outcome relies on the secretome of senescent cells and on the maintenance of their epigenetic marks. Using experimental models of senescence escape, we now described that the stability of this proliferative arrest relies on specific tRNAs and aminoacyl-tRNA synthetases. Following chemotherapy treatment, the DNA binding of the type III RNA polymerase was reduced to prevent tRNA transcription and induce a complete cell cycle arrest. By contrast, during senescence escape, specific tRNAs such as tRNA-Leu-CAA and tRNA-Tyr-GTA were up-regulated. Reducing tRNA transcription appears necessary to control the strength of senescence since RNA pol III inhibition through BRF1 depletion maintained senescence and blocked the generation of escaping cells. mTOR inhibition also prevented chemotherapy-induced senescence escape in association with a reduction of tRNA-Leu-CAA and tRNA-Tyr-GTA expression. Further confirming the role of the tRNA-Leu-CAA and tRNA-Tyr-GTA, results showed that their corresponding tRNA ligases, LARS and YARS, were necessary for senescence escape. This effect was specific since the CARS ligase had no effect on persistence. By contrast, the down-regulation of LARS and YARS reduced the emergence of persistent cells and this was associated with the modulation of E2F1 target genes expression. Overall, these findings highlight a new regulation of tRNA biology during senescence and suggest that specific tRNAs and ligases contribute to the strength and heterogeneity of this tumor suppressive pathway. Senescence is a tumor suppressive mechanism induced in response to oncogenes or chemotherapy. Senescence was initially defined as a definitive arrest of cell proliferation but doubts have emerged as to the value of this mechanism in terms of suppression. Recent findings published by several laboratories including our own have shown that some cells escape senescence to become more transformed. This study shows that different tRNAs are expressed in growing, senescent or emerging cells. The tRNA-Leu-CAA and tRNA-Tyr-GTA are up-regulated during senescence escape whereas this was not the case of the other tRNAs tested. In addition, using proteomic analysis and inactivation experiments, we found that the corresponding tRNA ligases, YARS for tRNA-Tyr-GTA and LARS for the tRNA-Leu-CAA, are necessary for senescence escape. Results also show that the expression of the tRNA-Leu-CAA and tRNA-Tyr-GTA are controlled by the mTOR pathway and that this kinase is necessary for senescence escape. Reducing tRNA transcription appears necessary to control the strength of senescence since RNA pol III inhibition maintained senescence and blocked the generation of escaping cells. In light of these results, we propose the hypothesis that the heterogeneity of tRNAs and ligases expression leads to distinct states of light or deep senescence.
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24
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Zhang S, Zhou YF, Cao J, Burley SK, Wang HY, Zheng XFS. mTORC1 Promotes ARID1A Degradation and Oncogenic Chromatin Remodeling in Hepatocellular Carcinoma. Cancer Res 2021; 81:5652-5665. [PMID: 34429326 PMCID: PMC8595749 DOI: 10.1158/0008-5472.can-21-0206] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 07/13/2021] [Accepted: 08/20/2021] [Indexed: 12/14/2022]
Abstract
The SWI/SNF chromatin remodeling complexes control accessibility of chromatin to transcriptional and coregulatory machineries. Chromatin remodeling plays important roles in normal physiology and diseases, particularly cancer. The ARID1A-containing SWI/SNF complex is commonly mutated and thought to be a key tumor suppressor in hepatocellular carcinoma (HCC), but its regulation in response to oncogenic signals remains poorly understood. mTOR is a conserved central controller of cell growth and an oncogenic driver of HCC. Remarkably, cancer mutations in mTOR and SWI/SNF complex are mutually exclusive in human HCC tumors, suggesting that they share a common oncogenic function. Here, we report that mTOR complex 1 (mTORC1) interact with ARID1A and regulates ubiquitination and proteasomal degradation of ARID1A protein. The mTORC1-ARID1A axis promoted oncogenic chromatin remodeling and YAP-dependent transcription, thereby enhancing liver cancer cell growth in vitro and tumor development in vivo. Conversely, excessive ARID1A expression counteracted AKT-driven liver tumorigenesis in vivo. Moreover, dysregulation of this axis conferred resistance to mTOR-targeted therapies. These findings demonstrate that the ARID1A-SWI/SNF complex is a regulatory target for oncogenic mTOR signaling, which is important for mTORC1-driven hepatocarcinogenesis, with implications for therapeutic interventions in HCC. SIGNIFICANCE: mTOR promotes oncogenic chromatin remodeling by controlling ARID1A degradation, which is important for liver tumorigenesis and response to mTOR- and YAP-targeted therapies in hepatocellular carcinoma.See related commentary by Pease and Fernandez-Zapico, p. 5608.
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Affiliation(s)
- Shanshan Zhang
- Rutgers Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, New Brunswick, New Jersey
- State Key Laboratory of Oncology in South China and Collaborative Innovation Center for Cancer Medicine, Sun Yat-Sen University Cancer Center, Guangzhou, China
| | - Yu-Feng Zhou
- State Key Laboratory of Oncology in South China and Collaborative Innovation Center for Cancer Medicine, Sun Yat-Sen University Cancer Center, Guangzhou, China
| | - Jian Cao
- Rutgers Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, New Brunswick, New Jersey
- Department of Medicine, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, New Jersey
| | - Stephen K Burley
- Rutgers Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, New Brunswick, New Jersey
- RCSB Protein Data Bank and Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, New Jersey
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey
- RCSB Protein Data Bank, School of Pharmacy and Pharmaceutical Sciences and San Diego, Supercomputing Center, University of California, San Diego, La Jolla, California
| | - Hui-Yun Wang
- Rutgers Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, New Brunswick, New Jersey.
- State Key Laboratory of Oncology in South China and Collaborative Innovation Center for Cancer Medicine, Sun Yat-Sen University Cancer Center, Guangzhou, China
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, New Jersey
| | - X F Steven Zheng
- Rutgers Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, New Brunswick, New Jersey.
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway, New Jersey
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25
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Gillen SL, Waldron JA, Bushell M. Codon optimality in cancer. Oncogene 2021; 40:6309-6320. [PMID: 34584217 PMCID: PMC8585667 DOI: 10.1038/s41388-021-02022-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 08/24/2021] [Accepted: 09/10/2021] [Indexed: 12/14/2022]
Abstract
A key characteristic of cancer cells is their increased proliferative capacity, which requires elevated levels of protein synthesis. The process of protein synthesis involves the translation of codons within the mRNA coding sequence into a string of amino acids to form a polypeptide chain. As most amino acids are encoded by multiple codons, the nucleotide sequence of a coding region can vary dramatically without altering the polypeptide sequence of the encoded protein. Although mutations that do not alter the final amino acid sequence are often thought of as silent/synonymous, these can still have dramatic effects on protein output. Because each codon has a distinct translation elongation rate and can differentially impact mRNA stability, each codon has a different degree of 'optimality' for protein synthesis. Recent data demonstrates that the codon preference of a transcriptome matches the abundance of tRNAs within the cell and that this supply and demand between tRNAs and mRNAs varies between different cell types. The largest observed distinction is between mRNAs encoding proteins associated with proliferation or differentiation. Nevertheless, precisely how codon optimality and tRNA expression levels regulate cell fate decisions and their role in malignancy is not fully understood. This review describes the current mechanistic understanding on codon optimality, its role in malignancy and discusses the potential to target codon optimality therapeutically in the context of cancer.
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Affiliation(s)
- Sarah L Gillen
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK.
| | - Joseph A Waldron
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK
| | - Martin Bushell
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK.
- Institute of Cancer Sciences, University of Glasgow, Glasgow, UK, G61 1QH.
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26
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Cattelani C, Lesiak D, Liebscher G, Singer II, Stasyk T, Wallnöfer MH, Heberle AM, Corti C, Hess MW, Pfaller K, Kwiatkowski M, Pramstaller PP, Hicks AA, Thedieck K, Müller T, Huber LA, Eca Guimaraes de Araujo M. The SZT2 Interactome Unravels New Functions of the KICSTOR Complex. Cells 2021; 10:2711. [PMID: 34685691 PMCID: PMC8534408 DOI: 10.3390/cells10102711] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 09/20/2021] [Accepted: 10/05/2021] [Indexed: 12/25/2022] Open
Abstract
Seizure threshold 2 (SZT2) is a component of the KICSTOR complex which, under catabolic conditions, functions as a negative regulator in the amino acid-sensing branch of mTORC1. Mutations in this gene cause a severe neurodevelopmental and epileptic encephalopathy whose main symptoms include epilepsy, intellectual disability, and macrocephaly. As SZT2 remains one of the least characterized regulators of mTORC1, in this work we performed a systematic interactome analysis under catabolic and anabolic conditions. Besides numerous mTORC1 and AMPK signaling components, we identified clusters of proteins related to autophagy, ciliogenesis regulation, neurogenesis, and neurodegenerative processes. Moreover, analysis of SZT2 ablated cells revealed increased mTORC1 signaling activation that could be reversed by Rapamycin or Torin treatments. Strikingly, SZT2 KO cells also exhibited higher levels of autophagic components, independent of the physiological conditions tested. These results are consistent with our interactome data, in which we detected an enriched pool of selective autophagy receptors/regulators. Moreover, preliminary analyses indicated that SZT2 alters ciliogenesis. Overall, the data presented form the basis to comprehensively investigate the physiological functions of SZT2 that could explain major molecular events in the pathophysiology of developmental and epileptic encephalopathy in patients with SZT2 mutations.
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Affiliation(s)
- Cecilia Cattelani
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria; (C.C.); (D.L.); (G.L.); (I.I.S.); (T.S.); (M.H.W.); (L.A.H.)
- Institute for Biomedicine, Eurac Research, Affiliated Institute of the University of Lübeck, 39100 Bolzano, Italy; (C.C.); (P.P.P.); (A.A.H.)
| | - Dominik Lesiak
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria; (C.C.); (D.L.); (G.L.); (I.I.S.); (T.S.); (M.H.W.); (L.A.H.)
| | - Gudrun Liebscher
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria; (C.C.); (D.L.); (G.L.); (I.I.S.); (T.S.); (M.H.W.); (L.A.H.)
| | - Isabel I. Singer
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria; (C.C.); (D.L.); (G.L.); (I.I.S.); (T.S.); (M.H.W.); (L.A.H.)
| | - Taras Stasyk
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria; (C.C.); (D.L.); (G.L.); (I.I.S.); (T.S.); (M.H.W.); (L.A.H.)
| | - Moritz H. Wallnöfer
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria; (C.C.); (D.L.); (G.L.); (I.I.S.); (T.S.); (M.H.W.); (L.A.H.)
| | - Alexander M. Heberle
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, 6020 Innsbruck, Austria; (A.M.H.); (M.K.); (K.T.)
- Laboratory of Pediatrics, Section Systems Medicine of Metabolism and Signaling, University of Groningen, University Medical Center Groningen, 9700 RB Groningen, The Netherlands
| | - Corrado Corti
- Institute for Biomedicine, Eurac Research, Affiliated Institute of the University of Lübeck, 39100 Bolzano, Italy; (C.C.); (P.P.P.); (A.A.H.)
| | - Michael W. Hess
- Institute of Histology and Embryology, Medical University of Innsbruck, 6020 Innsbruck, Austria; (M.W.H.); (K.P.)
| | - Kristian Pfaller
- Institute of Histology and Embryology, Medical University of Innsbruck, 6020 Innsbruck, Austria; (M.W.H.); (K.P.)
| | - Marcel Kwiatkowski
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, 6020 Innsbruck, Austria; (A.M.H.); (M.K.); (K.T.)
| | - Peter P. Pramstaller
- Institute for Biomedicine, Eurac Research, Affiliated Institute of the University of Lübeck, 39100 Bolzano, Italy; (C.C.); (P.P.P.); (A.A.H.)
| | - Andrew A. Hicks
- Institute for Biomedicine, Eurac Research, Affiliated Institute of the University of Lübeck, 39100 Bolzano, Italy; (C.C.); (P.P.P.); (A.A.H.)
| | - Kathrin Thedieck
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, 6020 Innsbruck, Austria; (A.M.H.); (M.K.); (K.T.)
- Laboratory of Pediatrics, Section Systems Medicine of Metabolism and Signaling, University of Groningen, University Medical Center Groningen, 9700 RB Groningen, The Netherlands
- Department for Neuroscience, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, 26129 Oldenburg, Germany
| | - Thomas Müller
- Department of Pediatrics I, Medical University of Innsbruck, 6020 Innsbruck, Austria;
| | - Lukas A. Huber
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria; (C.C.); (D.L.); (G.L.); (I.I.S.); (T.S.); (M.H.W.); (L.A.H.)
- Austrian Drug Screening Institute, ADSI, 6020 Innsbruck, Austria
| | - Mariana Eca Guimaraes de Araujo
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria; (C.C.); (D.L.); (G.L.); (I.I.S.); (T.S.); (M.H.W.); (L.A.H.)
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27
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Bowry A, Kelly RDW, Petermann E. Hypertranscription and replication stress in cancer. Trends Cancer 2021; 7:863-877. [PMID: 34052137 DOI: 10.1016/j.trecan.2021.04.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 04/23/2021] [Accepted: 04/30/2021] [Indexed: 12/18/2022]
Abstract
Replication stress results from obstacles to replication fork progression, including ongoing transcription, which can cause transcription-replication conflicts. Oncogenic signaling can promote global increases in transcription activity, also termed hypertranscription. Despite the widely accepted importance of oncogene-induced hypertranscription, its study remains neglected compared with other causes of replication stress and genomic instability in cancer. A growing number of recent studies are reporting that oncogenes, such as RAS, and targeted cancer treatments, such as bromodomain and extraterminal motif (BET) bromodomain inhibitors, increase global transcription, leading to R-loop accumulation, transcription-replication conflicts, and the activation of replication stress responses. Here we discuss our mechanistic understanding of hypertranscription-induced replication stress and the resulting cellular responses, in the context of oncogenes and targeted cancer therapies.
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Affiliation(s)
- Akhil Bowry
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Richard D W Kelly
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK.
| | - Eva Petermann
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK.
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28
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González-Jiménez A, Campos A, Navarro F, Clemente-Blanco A, Calvo O. Regulation of Eukaryotic RNAPs Activities by Phosphorylation. Front Mol Biosci 2021; 8:681865. [PMID: 34250017 PMCID: PMC8268151 DOI: 10.3389/fmolb.2021.681865] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 06/07/2021] [Indexed: 01/11/2023] Open
Abstract
Evolutionarily conserved kinases and phosphatases regulate RNA polymerase II (RNAPII) transcript synthesis by modifying the phosphorylation status of the carboxyl-terminal domain (CTD) of Rpb1, the largest subunit of RNAPII. Proper levels of Rpb1-CTD phosphorylation are required for RNA co-transcriptional processing and to coordinate transcription with other nuclear processes, such as chromatin remodeling and histone modification. Whether other RNAPII subunits are phosphorylated and influences their role in gene expression is still an unanswered question. Much less is known about RNAPI and RNAPIII phosphorylation, whose subunits do not contain functional CTDs. However, diverse studies have reported that several RNAPI and RNAPIII subunits are susceptible to phosphorylation. Some of these phosphorylation sites are distributed within subunits common to all three RNAPs whereas others are only shared between RNAPI and RNAPIII. This suggests that the activities of all RNAPs might be finely modulated by phosphorylation events and raises the idea of a tight coordination between the three RNAPs. Supporting this view, the transcription by all RNAPs is regulated by signaling pathways that sense different environmental cues to adapt a global RNA transcriptional response. This review focuses on how the phosphorylation of RNAPs might regulate their function and we comment on the regulation by phosphorylation of some key transcription factors in the case of RNAPI and RNAPIII. Finally, we discuss the existence of possible common mechanisms that could coordinate their activities.
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Affiliation(s)
- Araceli González-Jiménez
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas, Universidad de Salamanca, Salamanca, Spain
| | - Adrián Campos
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas, Universidad de Salamanca, Salamanca, Spain
| | - Francisco Navarro
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Jaén, Spain.,Centro de Estudios Avanzados en Aceite de Oliva y Olivar, Universidad de Jaén, Jaén, Spain
| | - Andrés Clemente-Blanco
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas, Universidad de Salamanca, Salamanca, Spain
| | - Olga Calvo
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas, Universidad de Salamanca, Salamanca, Spain
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29
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Roles of tRNA metabolism in aging and lifespan. Cell Death Dis 2021; 12:548. [PMID: 34039958 PMCID: PMC8154886 DOI: 10.1038/s41419-021-03838-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 05/11/2021] [Accepted: 05/12/2021] [Indexed: 12/17/2022]
Abstract
Transfer RNAs (tRNAs) mainly function as adapter molecules that decode messenger RNAs (mRNAs) during protein translation by delivering amino acids to the ribosome. Traditionally, tRNAs are considered as housekeepers without additional functions. Nevertheless, it has become apparent from biological research that tRNAs are involved in various physiological and pathological processes. Aging is a form of gradual decline in physiological function that ultimately leads to increased vulnerability to multiple chronic diseases and death. Interestingly, tRNA metabolism is closely associated with aging and lifespan. In this review, we summarize the emerging roles of tRNA-associated metabolism, such as tRNA transcription, tRNA molecules, tRNA modifications, tRNA aminoacylation, and tRNA derivatives, in aging and lifespan, aiming to provide new ideas for developing therapeutics and ultimately extending lifespan in humans.
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30
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Böhm R, Imseng S, Jakob RP, Hall MN, Maier T, Hiller S. The dynamic mechanism of 4E-BP1 recognition and phosphorylation by mTORC1. Mol Cell 2021; 81:2403-2416.e5. [PMID: 33852892 DOI: 10.1016/j.molcel.2021.03.031] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 02/22/2021] [Accepted: 03/18/2021] [Indexed: 10/21/2022]
Abstract
The activation of cap-dependent translation in eukaryotes requires multisite, hierarchical phosphorylation of 4E-BP by the 1 MDa kinase mammalian target of rapamycin complex 1 (mTORC1). To resolve the mechanism of this hierarchical phosphorylation at the atomic level, we monitored by NMR spectroscopy the interaction of intrinsically disordered 4E binding protein isoform 1 (4E-BP1) with the mTORC1 subunit regulatory-associated protein of mTOR (Raptor). The N-terminal RAIP motif and the C-terminal TOR signaling (TOS) motif of 4E-BP1 bind separate sites in Raptor, resulting in avidity-based tethering of 4E-BP1. This tethering orients the flexible central region of 4E-BP1 toward the mTORC1 kinase site for phosphorylation. The structural constraints imposed by the two tethering interactions, combined with phosphorylation-induced conformational switching of 4E-BP1, explain the hierarchy of 4E-BP1 phosphorylation by mTORC1. Furthermore, we demonstrate that mTORC1 recognizes both free and eIF4E-bound 4E-BP1, allowing rapid phosphorylation of the entire 4E-BP1 pool and efficient activation of translation. Finally, our findings provide a mechanistic explanation for the differential rapamycin sensitivity of the 4E-BP1 phosphorylation sites.
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Affiliation(s)
- Raphael Böhm
- Biozentrum, University of Basel, 4056 Basel, Switzerland
| | - Stefan Imseng
- Biozentrum, University of Basel, 4056 Basel, Switzerland
| | - Roman P Jakob
- Biozentrum, University of Basel, 4056 Basel, Switzerland
| | - Michael N Hall
- Biozentrum, University of Basel, 4056 Basel, Switzerland.
| | - Timm Maier
- Biozentrum, University of Basel, 4056 Basel, Switzerland.
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31
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Molecular Characterization of Paralichthys olivaceus MAF1 and Its Potential Role as an Anti-Viral Hemorrhagic Septicaemia Virus Factor in Hirame Natural Embryo Cells. Int J Mol Sci 2021; 22:ijms22031353. [PMID: 33572970 PMCID: PMC7866426 DOI: 10.3390/ijms22031353] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 01/25/2021] [Accepted: 01/26/2021] [Indexed: 12/18/2022] Open
Abstract
MAF1 is a global suppressor of RNA polymerase III-dependent transcription, and is conserved from yeast to human. Growing evidence supports the involvement of MAF1 in the immune response of mammals, but its biological functions in fish are unknown. We isolated and characterized Maf1 from the olive flounder Paralichthys olivaceus (PoMaf1). The coding region of PoMaf1 comprised 738 bp encoding a 245-amino-acid protein. The deduced PoMAF1 amino acid sequence shared features with those of MAF1 orthologues from vertebrates. PoMaf1 mRNA was detected in all tissues examined, and the levels were highest in eye and muscle tissue. The PoMaf1 mRNA level increased during early development. In addition, the PoMaf1 transcript level decreased during viral hemorrhagic septicemia virus (VHSV) infection of flounder hirame natural embryo (HINAE) cells. To investigate the role of PoMaf1 in VHSV infection, single-cell-derived PoMaf1 knockout HINAE cells were generated using the clustered regularly interspaced short palindromic repeats/CRISPR-associated-9 (CRISPR/Cas9) system, and cell clones with complete disruption of PoMaf1 were selected. PoMaf1 disruption increased the VHSV glycoprotein (G) mRNA levels during VHSV infection of HINAE cells, implicating PoMAF1 in the immune response to VSHV infection. To our knowledge, this is the first study to characterize fish Maf1, which may play a role in the response to viral infection.
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32
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Avcilar-Kucukgoze I, Kashina A. Hijacking tRNAs From Translation: Regulatory Functions of tRNAs in Mammalian Cell Physiology. Front Mol Biosci 2020; 7:610617. [PMID: 33392265 PMCID: PMC7773854 DOI: 10.3389/fmolb.2020.610617] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Accepted: 11/10/2020] [Indexed: 12/12/2022] Open
Abstract
Transfer tRNAs (tRNAs) are small non-coding RNAs that are highly conserved in all kingdoms of life. Originally discovered as the molecules that deliver amino acids to the growing polypeptide chain during protein synthesis, tRNAs have been believed for a long time to play exclusive role in translation. However, recent studies have identified key roles for tRNAs and tRNA-derived small RNAs in multiple other processes, including regulation of transcription and translation, posttranslational modifications, stress response, and disease. These emerging roles suggest that tRNAs may be central players in the complex machinery of biological regulatory pathways. Here we overview these non-canonical roles of tRNA in normal physiology and disease, focusing largely on eukaryotic and mammalian systems.
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Affiliation(s)
- Irem Avcilar-Kucukgoze
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Anna Kashina
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United States
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33
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Kumar M, Skillman K, Duraisingh MT. Linking nutrient sensing and gene expression in Plasmodium falciparum blood-stage parasites. Mol Microbiol 2020; 115:891-900. [PMID: 33236377 DOI: 10.1111/mmi.14652] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 11/17/2020] [Accepted: 11/20/2020] [Indexed: 12/21/2022]
Abstract
Malaria is one of the most life-threatening infectious diseases worldwide, caused by infection of humans with parasites of the genus Plasmodium. The complex life cycle of Plasmodium parasites is shared between two hosts, with infection of multiple cell types, and the parasite needs to adapt for survival and transmission through significantly different metabolic environments. Within the blood-stage alone, parasites encounter changing levels of key nutrients, including sugars, amino acids, and lipids, due to differences in host dietary nutrition, cellular tropism, and pathogenesis. In this review, we consider the mechanisms that the most lethal of malaria parasites, Plasmodium falciparum, uses to sense nutrient levels and elicit changes in gene expression during blood-stage infections. These changes are brought about by several metabolic intermediates and their corresponding sensor proteins. Sensing of distinct nutritional signals can drive P. falciparum to alter the key blood-stage processes of proliferation, antigenic variation, and transmission.
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Affiliation(s)
- Manish Kumar
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Kristen Skillman
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Manoj T Duraisingh
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA
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34
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Zhou X, Zhong Y, Molinar-Inglis O, Kunkel MT, Chen M, Sun T, Zhang J, Shyy JYJ, Trejo J, Newton AC, Zhang J. Location-specific inhibition of Akt reveals regulation of mTORC1 activity in the nucleus. Nat Commun 2020; 11:6088. [PMID: 33257668 PMCID: PMC7705703 DOI: 10.1038/s41467-020-19937-w] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 10/27/2020] [Indexed: 12/13/2022] Open
Abstract
The mechanistic target of rapamycin complex 1 (mTORC1) integrates growth, nutrient and energy status cues to control cell growth and metabolism. While mTORC1 activation at the lysosome is well characterized, it is not clear how this complex is regulated at other subcellular locations. Here, we combine location-selective kinase inhibition, live-cell imaging and biochemical assays to probe the regulation of growth factor-induced mTORC1 activity in the nucleus. Using a nuclear targeted Akt Substrate-based Tandem Occupancy Peptide Sponge (Akt-STOPS) that we developed for specific inhibition of Akt, a critical upstream kinase, we show that growth factor-stimulated nuclear mTORC1 activity requires nuclear Akt activity. Further mechanistic dissection suggests that nuclear Akt activity mediates growth factor-induced nuclear translocation of Raptor, a regulatory scaffolding component in mTORC1, and localization of Raptor to the nucleus results in nuclear mTORC1 activity in the absence of growth factor stimulation. Taken together, these results reveal a mode of regulation of mTORC1 that is distinct from its lysosomal activation, which controls mTORC1 activity in the nuclear compartment.
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Affiliation(s)
- Xin Zhou
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA
| | - Yanghao Zhong
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA
- Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA, USA
| | | | - Maya T Kunkel
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA
| | - Mingyuan Chen
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA
| | - Tengqian Sun
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA
| | - Jiao Zhang
- Division of Cardiology, Department of Medicine, University of California San Diego, La Jolla, CA, USA
| | - John Y-J Shyy
- Division of Cardiology, Department of Medicine, University of California San Diego, La Jolla, CA, USA
| | - JoAnn Trejo
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA
| | - Alexandra C Newton
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA
| | - Jin Zhang
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA.
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA.
- Department of Chemistry & Biochemistry, University of California, San Diego, La Jolla, CA, USA.
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35
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Roles for the RNA polymerase III regulator MAFR-1 in regulating sperm quality in Caenorhabditis elegans. Sci Rep 2020; 10:19367. [PMID: 33168938 PMCID: PMC7652826 DOI: 10.1038/s41598-020-76423-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 10/27/2020] [Indexed: 11/08/2022] Open
Abstract
The negative regulator of RNA polymerase (pol) III mafr-1 has been shown to affect RNA pol III transcript abundance, lipid biosynthesis and storage, progeny output, and lifespan. We deleted mafr-1 from the Caenorhabditis elegans genome and found that animals lacking mafr-1 replicated many phenotypes from previous RNAi-based studies and discovered a new sperm-specific role. Utilizing a yeast two-hybrid assay, we discovered several novel interactors of MAFR-1 that are expressed in a sperm- and germline-enriched manner. In support of a role for MAFR-1 in the male germline, we found mafr-1 null males have smaller spermatids that are less capable in competition for fertilization; a phenotype that was dependent on RNA pol III activity. Restoration of MAFR-1 expression specifically in the germline rescued the spermatid-related phenotypes, suggesting a cell autonomous role for MAFR-1 in nematode male fertility. Based on the high degree of conservation of Maf1 activity across species, our study may inform similar roles for Maf1 and RNA pol III in mammalian male fertility.
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36
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Chen Y, Zhou X. Research progress of mTOR inhibitors. Eur J Med Chem 2020; 208:112820. [PMID: 32966896 DOI: 10.1016/j.ejmech.2020.112820] [Citation(s) in RCA: 106] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/16/2020] [Accepted: 09/03/2020] [Indexed: 12/25/2022]
Abstract
Mammalian target of rapamycin (mTOR) is a highly conserved Serine/Threonine (Ser/Thr) protein kinase, which belongs to phosphatidylinositol-3-kinase-related kinase (PIKK) protein family. mTOR exists as two types of protein complex: mTORC1 and mTORC2, which act as central controller regulating processes of cell metabolism, growth, proliferation, survival and autophagy. The mTOR inhibitors block mTOR signaling pathway, producing anti-inflammatory, anti-proliferative, autophagy and apoptosis induction effects, thus mTOR inhibitors are mainly used in cancer therapy. At present, mTOR inhibitors are divided into four categories: Antibiotic allosteric mTOR inhibitors (first generation), ATP-competitive mTOR inhibitors (second generation), mTOR/PI3K dual inhibitors (second generation) and other new mTOR inhibitors (third generation). In this article, these four categories of mTOR inhibitors and their structures, properties and some clinical researches will be introduced. Among them, we focus on the structure of mTOR inhibitors and try to analyze the structure-activity relationship. mTOR inhibitors are classified according to their chemical structure and their contents are introduced systematically. Moreover, some natural products that have direct or indirect mTOR inhibitory activities are introduced together. In this article, we analyzed the target, binding mode and structure-activity relationship of each generation of mTOR inhibitors and proposed two hypothetic scaffolds (the inverted-Y-shape scaffold and the C-shape scaffold) for the second generation of mTOR inhibitors. These findings may provide some help or reference for drug designing, drug modification or the future development of mTOR inhibitor.
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Affiliation(s)
- Yifan Chen
- School of Pharmaceutical Sciences, Jilin University, Changchun, 130021, China
| | - Xiaoping Zhou
- School of Pharmaceutical Sciences, Jilin University, Changchun, 130021, China.
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37
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Oliveira Andrade M, Sforça ML, Batista FAH, Figueira ACM, Benedetti CE. The MAF1 Phosphoregulatory Region Controls MAF1 Interaction with the RNA Polymerase III C34 Subunit and Transcriptional Repression in Plants. THE PLANT CELL 2020; 32:3019-3035. [PMID: 32641350 PMCID: PMC7474290 DOI: 10.1105/tpc.20.00297] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 06/18/2020] [Accepted: 07/06/2020] [Indexed: 05/13/2023]
Abstract
MAF1 is a phosphoprotein that plays a critical role in cell growth control as the central regulator of RNA polymerase (Pol) III activity. Citrus MAF1 (CsMAF1) was identified as a direct target of PthA4, a bacterial effector protein required to induce tumors in citrus. CsMAF1 binds to Pol III to restrict transcription; however, exactly how CsMAF1 interacts with the polymerase and how phosphorylation modulates this interaction is unknown. Moreover, how CsMAF1 binds PthA4 is also obscure. Here we show that CsMAF1 binds predominantly to the WH1 domain of the citrus Pol III subunit C34 (CsC34) and that its phosphoregulatory region, comprising loop-3 and α-helix-2, contributes to this interaction. We also show that phosphorylation of this region decreases CsMAF1 affinity to CsC34, leading to Pol III derepression, and that Ser 45, found only in plant MAF1 proteins, is critical for CsC34 interaction and is phosphorylated by a new citrus AGC1 kinase. Additionally, we show that the C-terminal region of the citrus TFIIIB component BRF1 competes with CsMAF1 for CsC34 interaction, whereas the C-terminal region of CsMAF1 is essential for PthA4 binding. Based on CsMAF1 structural data, we propose a mechanism for how CsMAF1 represses Pol III transcription and how phosphorylation controls this process.
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Affiliation(s)
- Maxuel Oliveira Andrade
- Brazilian Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials, 13083-100 Campinas, São Paulo, Brazil
| | - Mauricio Luis Sforça
- Brazilian Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials, 13083-100 Campinas, São Paulo, Brazil
| | - Fernanda Aparecida Heleno Batista
- Brazilian Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials, 13083-100 Campinas, São Paulo, Brazil
| | - Ana Carolina Migliorini Figueira
- Brazilian Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials, 13083-100 Campinas, São Paulo, Brazil
| | - Celso Eduardo Benedetti
- Brazilian Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials, 13083-100 Campinas, São Paulo, Brazil
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38
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Kapur M, Ganguly A, Nagy G, Adamson SI, Chuang JH, Frankel WN, Ackerman SL. Expression of the Neuronal tRNA n-Tr20 Regulates Synaptic Transmission and Seizure Susceptibility. Neuron 2020; 108:193-208.e9. [PMID: 32853550 DOI: 10.1016/j.neuron.2020.07.023] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 06/07/2020] [Accepted: 07/19/2020] [Indexed: 12/31/2022]
Abstract
The mammalian genome has hundreds of nuclear-encoded tRNAs, but the contribution of individual tRNA genes to cellular and organismal function remains unknown. Here, we demonstrate that mutations in a neuronally enriched arginine tRNA, n-Tr20, increased seizure threshold and altered synaptic transmission. n-Tr20 expression also modulated seizures caused by an epilepsy-linked mutation in Gabrg2, a gene encoding a GABAA receptor subunit. Loss of n-Tr20 altered translation initiation by activating the integrated stress response and suppressing mTOR signaling, the latter of which may contribute to altered neurotransmission in mutant mice. Deletion of a highly expressed isoleucine tRNA similarly altered these signaling pathways in the brain, suggesting that regulation of translation initiation is a conserved response to tRNA loss. Our data indicate that loss of a single member of a tRNA family results in multiple cellular phenotypes, highlighting the disease-causing potential of tRNA mutations.
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Affiliation(s)
- Mridu Kapur
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Archan Ganguly
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Gabor Nagy
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
| | - Scott I Adamson
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA; Department of Genetics and Genome Sciences, Institute for Systems Genomics, UConn Health, Farmington, CT 06030, USA
| | - Jeffrey H Chuang
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
| | - Wayne N Frankel
- Institute for Genomic Medicine, Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Susan L Ackerman
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA.
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39
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Otsubo Y, Kamada Y, Yamashita A. Novel Links between TORC1 and Traditional Non-Coding RNA, tRNA. Genes (Basel) 2020; 11:E956. [PMID: 32825021 PMCID: PMC7563549 DOI: 10.3390/genes11090956] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/17/2020] [Accepted: 08/17/2020] [Indexed: 12/19/2022] Open
Abstract
Target of rapamycin (TOR) is a serine/threonine kinase that modulates cell growth and metabolism in response to environmental changes. Transfer RNA (tRNA) is an abundant and ubiquitous small non-coding RNA that is essential in the translation of mRNAs. Beyond its canonical role, it has been revealed that tRNAs have more diverse functions. TOR complex 1 (TORC1), which is one of the two TOR complexes, regulates tRNA synthesis by controlling RNA polymerase III. In addition to tRNA synthesis regulation, recent studies have revealed hidden connections between TORC1 and tRNA, which are both essential players in eukaryotic cellular activities. Here, we review the accumulating findings on the regulatory links between TORC1 and tRNA-particularly those links in the budding yeast Saccharomyces cerevisiae and the fission yeast Schizosaccharomyces pombe.
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Affiliation(s)
- Yoko Otsubo
- National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan; (Y.O.); (Y.K.)
- National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292, Japan
- Center for Novel Science Initiatives, National Institutes of Natural Sciences, Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - Yoshiaki Kamada
- National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan; (Y.O.); (Y.K.)
- Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - Akira Yamashita
- National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan; (Y.O.); (Y.K.)
- Center for Novel Science Initiatives, National Institutes of Natural Sciences, Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan
- Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan
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40
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Laribee RN, Weisman R. Nuclear Functions of TOR: Impact on Transcription and the Epigenome. Genes (Basel) 2020; 11:E641. [PMID: 32532005 PMCID: PMC7349558 DOI: 10.3390/genes11060641] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/04/2020] [Accepted: 06/09/2020] [Indexed: 12/15/2022] Open
Abstract
The target of rapamycin (TOR) protein kinase is at the core of growth factor- and nutrient-dependent signaling pathways that are well-known for their regulation of metabolism, growth, and proliferation. However, TOR is also involved in the regulation of gene expression, genomic and epigenomic stability. TOR affects nuclear functions indirectly through its activity in the cytoplasm, but also directly through active nuclear TOR pools. The mechanisms by which TOR regulates its nuclear functions are less well-understood compared with its cytoplasmic activities. TOR is an important pharmacological target for several diseases, including cancer, metabolic and neurological disorders. Thus, studies of the nuclear functions of TOR are important for our understanding of basic biological processes, as well as for clinical implications.
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Affiliation(s)
- R. Nicholas Laribee
- Department of Pathology and Laboratory Medicine, College of Medicine and Center for Cancer Research, University of Tennessee Health Science Center, 19 South Manassas, Cancer Research Building Rm 318, Memphis, TN 38163, USA
| | - Ronit Weisman
- Department of Natural and Life Sciences, The Open University of Israel, University Road 1, Ra’anana 4353701, Israel
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41
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SOX4-mediated repression of specific tRNAs inhibits proliferation of human glioblastoma cells. Proc Natl Acad Sci U S A 2020; 117:5782-5790. [PMID: 32123087 DOI: 10.1073/pnas.1920200117] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Transfer RNAs (tRNAs) are products of RNA polymerase III (Pol III) and essential for mRNA translation and ultimately cell growth and proliferation. Whether and how individual tRNA genes are specifically regulated is not clear. Here, we report that SOX4, a well-known Pol II-dependent transcription factor that is critical for neurogenesis and reprogramming of somatic cells, also directly controls, unexpectedly, the expression of a subset of tRNA genes and therefore protein synthesis and proliferation of human glioblastoma cells. Genome-wide location analysis through chromatin immunoprecipitation-sequencing uncovers specific targeting of SOX4 to a subset of tRNA genes, including those for tRNAiMet Mechanistically, sequence-specific SOX4-binding impedes the recruitment of TATA box binding protein and Pol III to tRNA genes and thereby represses their expression. CRISPR/Cas9-mediated down-regulation of tRNAiMet greatly inhibits growth and proliferation of human glioblastoma cells. Conversely, ectopic tRNAiMet partially rescues SOX4-mediated repression of cell proliferation. Together, these results uncover a regulatory mode of individual tRNA genes to control cell behavior. Such regulation may coordinate codon usage and translation efficiency to meet the demands of diverse tissues and cell types, including cancer cells.
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42
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Liapi E, van Bilsen M, Verjans R, Schroen B. tRNAs and tRNA fragments as modulators of cardiac and skeletal muscle function. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118465. [DOI: 10.1016/j.bbamcr.2019.03.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 03/20/2019] [Accepted: 03/25/2019] [Indexed: 12/11/2022]
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43
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Napoli M, Flores ER. The p53 family reaches the final frontier: the variegated regulation of the dark matter of the genome by the p53 family in cancer. RNA Biol 2020; 17:1636-1647. [PMID: 31910062 PMCID: PMC7567494 DOI: 10.1080/15476286.2019.1710054] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The tumour suppressor p53 and its paralogues, p63 and p73, are essential to maintain cellular homoeostasis and the integrity of the cell's genetic material, thus meriting the title of 'guardians of the genome'. The p53 family members are transcription factors and fulfill their activities by controlling the expression of protein-coding and non-coding genes. Here, we review how the latter group transcended from the 'dark matter' of the transcriptome, providing unexpected and intriguing anti-cancer therapeutic strategies.
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Affiliation(s)
- Marco Napoli
- Department of Molecular Oncology, H. Lee Moffitt Cancer Center and Research Institute , Tampa, FL, USA.,Cancer Biology and Evolution Program, H. Lee Moffitt Cancer Center and Research Institute , Tampa, FL, USA
| | - Elsa R Flores
- Department of Molecular Oncology, H. Lee Moffitt Cancer Center and Research Institute , Tampa, FL, USA.,Cancer Biology and Evolution Program, H. Lee Moffitt Cancer Center and Research Institute , Tampa, FL, USA
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44
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Inhibition of tRNA Gene Transcription by the Immunosuppressant Mycophenolic Acid. Mol Cell Biol 2019; 40:MCB.00294-19. [PMID: 31658995 PMCID: PMC6908259 DOI: 10.1128/mcb.00294-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 10/21/2019] [Indexed: 12/11/2022] Open
Abstract
Mycophenolic acid (MPA) is the active metabolite of mycophenolate mofetil, a drug that is widely used for immunosuppression in organ transplantation and autoimmune diseases, as well as anticancer chemotherapy. It inhibits IMP dehydrogenase, a rate-limiting enzyme in de novo synthesis of guanidine nucleotides. Mycophenolic acid (MPA) is the active metabolite of mycophenolate mofetil, a drug that is widely used for immunosuppression in organ transplantation and autoimmune diseases, as well as anticancer chemotherapy. It inhibits IMP dehydrogenase, a rate-limiting enzyme in de novo synthesis of guanidine nucleotides. MPA treatment interferes with transcription elongation, resulting in a drastic reduction of pre-rRNA and pre-tRNA synthesis, the disruption of the nucleolus, and consequently cell cycle arrest. Here, we investigated the mechanism whereby MPA inhibits RNA polymerase III (Pol III) activity, in both yeast and mammalian cells. We show that MPA rapidly inhibits Pol III by depleting GTP. Although MPA treatment can activate p53, this is not required for Pol III transcriptional inhibition. The Pol III repressor MAF1 is also not responsible for inhibiting Pol III in response to MPA treatment. We show that upon MPA treatment, the levels of selected Pol III subunits decrease, but this is secondary to transcriptional inhibition. Chromatin immunoprecipitation (ChIP) experiments show that Pol III does not fully dissociate from tRNA genes in yeast treated with MPA, even though there is a sharp decrease in the levels of newly transcribed tRNAs. We propose that in yeast, GTP depletion may lead to Pol III stalling.
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45
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Wang X, Rusin A, Walkey CJ, Lin JJ, Johnson DL. The RNA polymerase III repressor MAF1 is regulated by ubiquitin-dependent proteasome degradation and modulates cancer drug resistance and apoptosis. J Biol Chem 2019; 294:19255-19268. [PMID: 31645432 DOI: 10.1074/jbc.ra119.008849] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 10/01/2019] [Indexed: 01/03/2023] Open
Abstract
MAF1 homolog, negative regulator of RNA polymerase III (MAF1) is a key repressor of RNA polymerase (pol) III-dependent transcription and functions as a tumor suppressor. Its expression is frequently down-regulated in primary human hepatocellular carcinomas (HCCs). However, this reduction in MAF1 protein levels does not correlate with its transcript levels, indicating that MAF1 is regulated post-transcriptionally. Here, we demonstrate that MAF1 is a labile protein whose levels are regulated through the ubiquitin-dependent proteasome pathway. We found that MAF1 ubiquitination is enhanced upon mTOR complex 1 (TORC1)-mediated phosphorylation at Ser-75. Moreover, we observed that the E3 ubiquitin ligase cullin 2 (CUL2) critically regulates MAF1 ubiquitination and controls its stability and subsequent RNA pol III-dependent transcription. Analysis of the phenotypic consequences of modulating either CUL2 or MAF1 protein expression revealed changes in actin cytoskeleton reorganization and altered sensitivity to doxorubicin-induced apoptosis. Repression of RNA pol III-dependent transcription by chemical inhibition or knockdown of BRF1 RNA pol III transcription initiation factor subunit (BRF1) enhanced HCC cell sensitivity to doxorubicin, suggesting that MAF1 regulates doxorubicin resistance in HCC by controlling RNA pol III-dependent transcription. Together, our results identify the ubiquitin proteasome pathway and CUL2 as important regulators of MAF1 levels. They suggest that decreases in MAF1 protein underlie chemoresistance in HCC and perhaps other cancers and point to an important role for MAF1 and RNA pol III-mediated transcription in chemosensitivity and apoptosis.
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Affiliation(s)
- Xianlong Wang
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030
| | - Aleksandra Rusin
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030
| | - Christopher J Walkey
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030
| | | | - Deborah L Johnson
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030
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46
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Ciesla M, Skowronek E, Boguta M. Function of TFIIIC, RNA polymerase III initiation factor, in activation and repression of tRNA gene transcription. Nucleic Acids Res 2019; 46:9444-9455. [PMID: 30053100 PMCID: PMC6182151 DOI: 10.1093/nar/gky656] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 07/10/2018] [Indexed: 01/09/2023] Open
Abstract
Transcription of transfer RNA genes by RNA polymerase III (Pol III) is controlled by general factors, TFIIIB and TFIIIC, and a negative regulator, Maf1. Here we report the interplay between TFIIIC and Maf1 in controlling Pol III activity upon the physiological switch of yeast from fermentation to respiration. TFIIIC directly competes with Pol III for chromatin occupancy as demonstrated by inversely correlated tDNA binding. The association of TFIIIC with tDNA was stronger under unfavorable respiratory conditions and in the presence of Maf1. Induction of tDNA transcription by glucose-activated protein kinase A (PKA) was correlated with the down-regulation of TFIIIC occupancy on tDNA. The conditions that activate the PKA signaling pathway promoted the binding of TFIIIB subunits, Brf1 and Bdp1, with tDNA, but decreased their interaction with TFIIIC. Association of Brf1 and Bdp1 with TFIIIC was much stronger under repressive conditions, potentially restricting TFIIIB recruitment to tDNA and preventing Pol III recruitment. Altogether, we propose a model in which, depending on growth conditions, TFIIIC promotes activation or repression of tDNA transcription.
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Affiliation(s)
- Malgorzata Ciesla
- Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland
| | - Ewa Skowronek
- Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland
| | - Magdalena Boguta
- Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland
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47
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Morcelle C, Menoyo S, Morón-Duran FD, Tauler A, Kozma SC, Thomas G, Gentilella A. Oncogenic MYC Induces the Impaired Ribosome Biogenesis Checkpoint and Stabilizes p53 Independent of Increased Ribosome Content. Cancer Res 2019; 79:4348-4359. [PMID: 31292158 DOI: 10.1158/0008-5472.can-18-2718] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 05/07/2019] [Accepted: 07/03/2019] [Indexed: 11/16/2022]
Abstract
The role of MYC in regulating p53 stability as a function of increased ribosome biogenesis is controversial. On the one hand, it was suggested that MYC drives the overexpression of ribosomal proteins (RP)L5 and RPL11, which bind and inhibit HDM2, stabilizing p53. On the other, it has been proposed that increased ribosome biogenesis leads the consumption of RPL5/RPL11 into nascent ribosomes, reducing p53 levels and enhancing tumorigenesis. Here, we show that the components that make up the recently described impaired ribosome biogenesis checkpoint (IRBC) complex, RPL5, RPL11, and 5S rRNA, are reduced following MYC silencing. This leads to a rapid reduction in p53 protein half-life in an HDM2-dependent manner. In contrast, MYC induction leads to increased ribosome biogenesis and p53 protein stabilization. Unexpectedly, there is no change in free RPL5/RPL11 levels, but there is a striking increase in IRBC complex bound to HDM2. Our data support a cell-intrinsic tumor-suppressor response to MYC expression, which is presently being exploited to treat cancer. SIGNIFICANCE: Oncogenic MYC induces the impaired ribosome biogenesis checkpoint, which could be potentially targeted for cancer treatment.
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Affiliation(s)
- Carmen Morcelle
- Laboratory of Cancer Metabolism, ONCOBELL Program, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
| | - Sandra Menoyo
- Laboratory of Cancer Metabolism, ONCOBELL Program, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
| | - Francisco D Morón-Duran
- Laboratory of Cancer Metabolism, ONCOBELL Program, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
| | - Albert Tauler
- Laboratory of Cancer Metabolism, ONCOBELL Program, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain.,Department of Biochemistry and Physiology, Faculty of Pharmacy, University of Barcelona, Barcelona, Spain
| | - Sara C Kozma
- Laboratory of Cancer Metabolism, ONCOBELL Program, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
| | - George Thomas
- Laboratory of Cancer Metabolism, ONCOBELL Program, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain. .,Physiological Sciences Department, Faculty of Medicine and Health Science, University of Barcelona, Barcelona, Spain
| | - Antonio Gentilella
- Laboratory of Cancer Metabolism, ONCOBELL Program, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain. .,Department of Biochemistry and Physiology, Faculty of Pharmacy, University of Barcelona, Barcelona, Spain
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48
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Hua H, Kong Q, Zhang H, Wang J, Luo T, Jiang Y. Targeting mTOR for cancer therapy. J Hematol Oncol 2019; 12:71. [PMID: 31277692 PMCID: PMC6612215 DOI: 10.1186/s13045-019-0754-1] [Citation(s) in RCA: 511] [Impact Index Per Article: 102.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Accepted: 06/14/2019] [Indexed: 02/05/2023] Open
Abstract
Mechanistic target of rapamycin (mTOR) is a protein kinase regulating cell growth, survival, metabolism, and immunity. mTOR is usually assembled into several complexes such as mTOR complex 1/2 (mTORC1/2). In cooperation with raptor, rictor, LST8, and mSin1, key components in mTORC1 or mTORC2, mTOR catalyzes the phosphorylation of multiple targets such as ribosomal protein S6 kinase β-1 (S6K1), eukaryotic translation initiation factor 4E binding protein 1 (4E-BP1), Akt, protein kinase C (PKC), and type-I insulin-like growth factor receptor (IGF-IR), thereby regulating protein synthesis, nutrients metabolism, growth factor signaling, cell growth, and migration. Activation of mTOR promotes tumor growth and metastasis. Many mTOR inhibitors have been developed to treat cancer. While some of the mTOR inhibitors have been approved to treat human cancer, more mTOR inhibitors are being evaluated in clinical trials. Here, we update recent advances in exploring mTOR signaling and the development of mTOR inhibitors for cancer therapy. In addition, we discuss the mechanisms underlying the resistance to mTOR inhibitors in cancer cells.
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Affiliation(s)
- Hui Hua
- State Key Laboratory of Biotherapy, Laboratory of Stem Cell Biology, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Qingbin Kong
- Laboratory of Oncogene, Cancer Center, West China Hospital, Sichuan University, Chengdu, China
| | - Hongying Zhang
- Laboratory of Oncogene, Cancer Center, West China Hospital, Sichuan University, Chengdu, China
| | - Jiao Wang
- School of Basic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Ting Luo
- Cancer Center, West China Hospital, Sichuan University, Chengdu, China
| | - Yangfu Jiang
- Laboratory of Oncogene, Cancer Center, West China Hospital, Sichuan University, Chengdu, China.
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49
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Santos M, Fidalgo A, Varanda AS, Oliveira C, Santos MAS. tRNA Deregulation and Its Consequences in Cancer. Trends Mol Med 2019; 25:853-865. [PMID: 31248782 DOI: 10.1016/j.molmed.2019.05.011] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 05/24/2019] [Accepted: 05/28/2019] [Indexed: 02/06/2023]
Abstract
The expression of transfer RNAs (tRNAs) is deregulated in cancer cells but the mechanisms and functional meaning of such deregulation are poorly understood. The proteome of cancer cells is not fully encoded by their transcriptome, however, the contribution of mRNA translation to such diversity remains to be elucidated. We review data supporting the hypothesis that tRNA expression deregulation and translational error rate is an important contributor to proteome diversity and cell population heterogeneity, genome instability, and drug resistance in tumors. This hypothesis is aligned with recent data in various model organisms, showing unanticipated adaptive roles of translational errors (adaptive mistranslation), expression control of specific gene subsets by tRNAs, and proteome diversification by elevation of translational error rates in tumors.
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Affiliation(s)
- Mafalda Santos
- Expression Regulation in Cancer, Instituto de Investigação e Inovação em Saúde, University of Porto, Portugal; Institute of Molecular Pathology and Immunology University of Porto (IPATIMUP), Porto, Portugal; Department of Medical Sciences and Institute of Biomedicine - iBiMED, University of Aveiro, Aveiro, Portugal
| | - Ana Fidalgo
- Department of Medical Sciences and Institute of Biomedicine - iBiMED, University of Aveiro, Aveiro, Portugal
| | - A Sofia Varanda
- Expression Regulation in Cancer, Instituto de Investigação e Inovação em Saúde, University of Porto, Portugal; Institute of Molecular Pathology and Immunology University of Porto (IPATIMUP), Porto, Portugal; Department of Medical Sciences and Institute of Biomedicine - iBiMED, University of Aveiro, Aveiro, Portugal
| | - Carla Oliveira
- Expression Regulation in Cancer, Instituto de Investigação e Inovação em Saúde, University of Porto, Portugal; Institute of Molecular Pathology and Immunology University of Porto (IPATIMUP), Porto, Portugal; Department of Pathology, Medical Faculty of Porto, Porto, Portugal.
| | - Manuel A S Santos
- Department of Medical Sciences and Institute of Biomedicine - iBiMED, University of Aveiro, Aveiro, Portugal.
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von Walden F. Ribosome biogenesis in skeletal muscle: coordination of transcription and translation. J Appl Physiol (1985) 2019; 127:591-598. [PMID: 31219775 DOI: 10.1152/japplphysiol.00963.2018] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Skeletal muscle mass responds in a remarkable manner to alterations in loading and use. It has long been clear that skeletal muscle hypertrophy can be prevented by inhibiting RNA synthesis. Since 80% of the cell's total RNA has been estimated to be rRNA, this finding indicates that de novo production of rRNA via transcription of the corresponding genes is important for such hypertrophy to occur. Transcription of rDNA by RNA Pol I is the rate-limiting step in ribosome biogenesis, indicating in turn that this biogenesis strongly influences the hypertrophic response. The present minireview focuses on 1) a brief description of the key steps in ribosome biogenesis and the relationship of this process to skeletal muscle mass and 2) the coordination of ribosome biogenesis and protein synthesis for growth or atrophy, as exemplified by the intracellular AMPK and mTOR pathways.
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Affiliation(s)
- Ferdinand von Walden
- Division of Pediatric Neurology, Department of Women's and Children's Health, Karolinska Institute, Stockholm, Sweden
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