1
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Al-Lamki RS, Tolkovsky AM, Alawwami M, Lu W, Field SF, Wang J, Pober JS, Bradley JR. Tumor Necrosis Factor Receptor-2 Signals Clear-Cell Renal Carcinoma Proliferation via Phosphorylated 4E Binding Protein-1 and Mitochondrial Gene Translation. THE AMERICAN JOURNAL OF PATHOLOGY 2024; 194:1374-1387. [PMID: 38537932 DOI: 10.1016/j.ajpath.2024.02.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 02/08/2024] [Accepted: 02/21/2024] [Indexed: 04/09/2024]
Abstract
Clear-cell renal cell carcinoma (ccRCC), a tubular epithelial malignancy, secretes tumor necrosis factor (TNF), which signals ccRCC cells in an autocrine manner via two cell surface receptors, TNFR1 and TNFR2, to activate shared and distinct signaling pathways. Selective ligation of TNFR2 drives cell cycle entry of malignant cells via a signaling pathway involving epithelial tyrosine kinase, vascular endothelial cell growth factor receptor type 2, phosphatidylinositol-3-kinase, Akt, pSer727-Stat3, and mammalian target of rapamycin. In this study, phosphorylated 4E binding protein-1 (4EBP1) serine 65 (pSer65-4EBP1) was identified as a downstream target of this TNFR2 signaling pathway. pSer65-4EBP1 expression was significantly elevated relative to total 4EBP1 in ccRCC tissue compared with that in normal kidneys, with signal intensity increasing with malignant grade. Selective ligation of TNFR2 with the TNFR2-specific mutein increased pSer65-4EBP1 expression in organ cultures that co-localized with internalized TNFR2 in mitochondria and increased expression of mitochondrially encoded COX (cytochrome c oxidase subunit) Cox1, as well as nuclear-encoded Cox4/5b subunits. Pharmacologic inhibition of mammalian target of rapamycin reduced both TNFR2-specific mutein-mediated phosphorylation of 4EBP1 and cell cycle activation in tumor cells while increasing cell death. These results signify the importance of pSer65-4EBP1 in mediating TNFR2-driven cell-cycle entry in tumor cells in ccRCC and implicate a novel relationship between the TNFR2/pSer65-4EBP1/COX axis and mitochondrial function.
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MESH Headings
- Humans
- Adaptor Proteins, Signal Transducing/metabolism
- Adaptor Proteins, Signal Transducing/genetics
- Carcinoma, Renal Cell/metabolism
- Carcinoma, Renal Cell/pathology
- Carcinoma, Renal Cell/genetics
- Cell Cycle Proteins/metabolism
- Cell Cycle Proteins/genetics
- Cell Line, Tumor
- Cell Proliferation
- Kidney Neoplasms/metabolism
- Kidney Neoplasms/pathology
- Kidney Neoplasms/genetics
- Mitochondria/metabolism
- Phosphoproteins/metabolism
- Phosphorylation
- Protein Biosynthesis
- Receptors, Tumor Necrosis Factor, Type II/metabolism
- Receptors, Tumor Necrosis Factor, Type II/genetics
- Signal Transduction
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Affiliation(s)
- Rafia S Al-Lamki
- Department of Medicine, National Institute of Health Research Cambridge Biomedical Research Centre, University of Cambridge, Cambridge, United Kingdom.
| | - Aviva M Tolkovsky
- Department of Clinical Neurosciences, The Clifford Allbutt Building, University of Cambridge, Cambridge, United Kingdom
| | - Mohammad Alawwami
- Department of Medicine, National Institute of Health Research Cambridge Biomedical Research Centre, University of Cambridge, Cambridge, United Kingdom
| | - WanHua Lu
- Department of Medicine, National Institute of Health Research Cambridge Biomedical Research Centre, University of Cambridge, Cambridge, United Kingdom
| | - Sarah F Field
- Dementia Research Institute, Island Research Building, University of Cambridge, Cambridge, United Kingdom
| | - Jun Wang
- Department of Medicine, National Institute of Health Research Cambridge Biomedical Research Centre, University of Cambridge, Cambridge, United Kingdom
| | - Jordan S Pober
- Department of Immunobiology, Yale University, New Haven, Connecticut
| | - John R Bradley
- Department of Medicine, National Institute of Health Research Cambridge Biomedical Research Centre, University of Cambridge, Cambridge, United Kingdom
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2
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Lin P, Cao W, Chen X, Zhang N, Xing Y, Yang N. Role of mRNA-binding proteins in retinal neovascularization. Exp Eye Res 2024; 242:109870. [PMID: 38514023 DOI: 10.1016/j.exer.2024.109870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Revised: 03/06/2024] [Accepted: 03/18/2024] [Indexed: 03/23/2024]
Abstract
Retinal neovascularization (RNV) is a pathological process that primarily occurs in diabetic retinopathy, retinopathy of prematurity, and retinal vein occlusion. It is a common yet debilitating clinical condition that culminates in blindness. Urgent efforts are required to explore more efficient and less limiting therapeutic strategies. Key RNA-binding proteins (RBPs), crucial for post-transcriptional regulation of gene expression by binding to RNAs, are closely correlated with RNV development. RBP-RNA interactions are altered during RNV. Here, we briefly review the characteristics and functions of RBPs, and the mechanism of RNV. Then, we present insights into the role of the regulatory network of RBPs in RNV. HuR, eIF4E, LIN28B, SRSF1, METTL3, YTHDF1, Gal-1, HIWI1, and ZFR accelerate RNV progression, whereas YTHDF2 and hnRNPA2B1 hinder it. The mechanisms elucidated in this review provide a reference to guide the design of therapeutic strategies to reverse abnormal processes.
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Affiliation(s)
- Pei Lin
- Department of Ophthalmology, Renmin Hospital of Wuhan University, Jiefang Road #238, Wuhan, 430060, Hubei, China.
| | - Wenye Cao
- Department of Ophthalmology, Renmin Hospital of Wuhan University, Jiefang Road #238, Wuhan, 430060, Hubei, China.
| | - Xuemei Chen
- Department of Ophthalmology, Renmin Hospital of Wuhan University, Jiefang Road #238, Wuhan, 430060, Hubei, China.
| | - Ningzhi Zhang
- Department of Ophthalmology, Renmin Hospital of Wuhan University, Jiefang Road #238, Wuhan, 430060, Hubei, China.
| | - Yiqiao Xing
- Department of Ophthalmology, Renmin Hospital of Wuhan University, Jiefang Road #238, Wuhan, 430060, Hubei, China; Department of Ophthalmology, Aier Eye Hospital of Wuhan University, Hubei, China.
| | - Ning Yang
- Department of Ophthalmology, Renmin Hospital of Wuhan University, Jiefang Road #238, Wuhan, 430060, Hubei, China.
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3
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Yuan K, Xia F, Li Q, Zheng M, Shen H, Chen W, Yang H, Zhuang X, Zhang XY, Xiao Y, Yang P. Discovery of Potent, Selective, and Orally Bioavailable DYRK2 Inhibitors for the Treatment of Prostate Cancer. J Med Chem 2023; 66:16235-16256. [PMID: 38033250 DOI: 10.1021/acs.jmedchem.3c01626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
Prostate cancer (PCa) seriously threatens male health, and targeting dual-specificity tyrosine phosphorylation-regulated kinase 2 (DYRK2) has been verified to reduce PCa burden, while the research progress on the DYRK2 inhibitors was relatively slow. In this work, we discovered DYRK2 inhibitor 12 (IC50 = 9681 nM) through virtual screening. Subsequently, we performed systematic structural optimization to obtain 54 (IC50 = 14 nM). Compound 54 exhibited high selectivity among 215 kinases and significantly suppressed the proliferation and metastasis of PCa cells in vitro. Moreover, compound 54 displayed high safety, favorable bioavailability, and potent tumor growth inhibitory activity in vivo, which could be used as a potential candidate in the discovery of novel anti-PCa drugs.
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Affiliation(s)
- Kai Yuan
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Fei Xia
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Qiannan Li
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Mingming Zheng
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Hongtao Shen
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Weijiao Chen
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Huanaoyu Yang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Xujie Zhuang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Xiao-Yu Zhang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Yibei Xiao
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
- Institute of Innovative Drug Discovery and Development, China Pharmaceutical University, Nanjing 211198, China
| | - Peng Yang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
- Institute of Innovative Drug Discovery and Development, China Pharmaceutical University, Nanjing 211198, China
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4
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Xiong Z, Wang M, Wu J, Shi X. Tceal7 Regulates Skeletal Muscle Development through Its Interaction with Cdk1. Int J Mol Sci 2023; 24:ijms24076264. [PMID: 37047236 PMCID: PMC10094454 DOI: 10.3390/ijms24076264] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/23/2023] [Accepted: 03/25/2023] [Indexed: 03/29/2023] Open
Abstract
We have previously reported Tceal7 as a muscle-specific gene that represses myoblast proliferation and promotes myogenic differentiation. The regulatory mechanism of Tceal7 gene expression has been well clarified recently. However, the underlying mechanism of Tceal7 function in skeletal muscle development remains to be elucidated. In the present study, we have generated an MCK 6.5 kb-HA-Tceal7 transgenic model. The transgenic mice are born normally, while they have displayed defects in the growth of body weight and skeletal muscle myofiber during postnatal development. Although four RxL motifs have been identified in the Tceal7 protein sequence, we have not detected any direct protein-protein interaction between Tceal7 and Cyclin A2, Cyclin B1, Cylin D1, or Cyclin E1. Further analysis has revealed the interaction between Tceal7 and Cdk1 instead of Cdk2, Cdk4, or Cdk6. Transgenic overexpression of Tceal7 reduces phosphorylation of 4E-BP1 Ser65, p70S6K1 Thr389, and Cdk substrates in skeletal muscle. In summary, these studies have revealed a novel mechanism of Tceal7 in skeletal muscle development.
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5
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Yuan K, Shen H, Zheng M, Xia F, Li Q, Chen W, Ji M, Yang H, Zhuang X, Cai Z, Min W, Wang X, Xiao Y, Yang P. Discovery of Potent DYRK2 Inhibitors with High Selectivity, Great Solubility, and Excellent Safety Properties for the Treatment of Prostate Cancer. J Med Chem 2023; 66:4215-4230. [PMID: 36800260 DOI: 10.1021/acs.jmedchem.3c00106] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Prostate cancer (PCa) is a common male cancer with high incidence and mortality, and hormonal therapy as the major treatment for PCa patients is troubled by the inevitable resistance that makes us identify novel targets for PCa. Dual-specificity tyrosine phosphorylation-regulated kinase 2 (DYRK2) was found to be an effective target for the treatment of PCa, but the research on its inhibitors is rather little. In this work, a potent DYRK2 inhibitor 43 (IC50 = 0.6 nM) was acquired through virtual screening and structural optimization, which displayed high selectivity among 205 kinases; meanwhile, detailed interactions of 43 with DYRK2 were illustrated by the cocrystal. Furthermore, 43 possessed great water solubility (29.5 mg/mL), favorable safety properties (LD50 > 10,000 mg/kg), and potent anti-PCa activities, which could be used as a potential candidate in further preclinical studies.
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Affiliation(s)
- Kai Yuan
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Hongtao Shen
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Mingming Zheng
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Fei Xia
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Qiannan Li
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Weijiao Chen
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Minghui Ji
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Huanaoyu Yang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Xujie Zhuang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Zeyu Cai
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Wenjian Min
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Xiao Wang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
- Institute of Innovative Drug Discovery and Development, China Pharmaceutical University, Nanjing 211198, China
| | - Yibei Xiao
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
- Institute of Innovative Drug Discovery and Development, China Pharmaceutical University, Nanjing 211198, China
| | - Peng Yang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
- Institute of Innovative Drug Discovery and Development, China Pharmaceutical University, Nanjing 211198, China
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6
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Yuan K, Li Z, Kuang W, Wang X, Ji M, Chen W, Ding J, Li J, Min W, Sun C, Ye X, Lu M, Wang L, Ge H, Jiang Y, Hao H, Xiao Y, Yang P. Targeting dual-specificity tyrosine phosphorylation-regulated kinase 2 with a highly selective inhibitor for the treatment of prostate cancer. Nat Commun 2022; 13:2903. [PMID: 35614066 PMCID: PMC9133015 DOI: 10.1038/s41467-022-30581-4] [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: 05/23/2021] [Accepted: 05/05/2022] [Indexed: 11/10/2022] Open
Abstract
Prostate cancer (PCa) is one of the most prevalent cancers in men worldwide, and hormonal therapy plays a key role in the treatment of PCa. However, the drug resistance of hormonal therapy makes it urgent and necessary to identify novel targets for PCa treatment. Herein, dual-specificity tyrosine phosphorylation-regulated kinase 2 (DYRK2) is found and confirmed to be highly expressed in the PCa tissues and cells, and knock-down of DYRK2 remarkably reduces PCa burden in vitro and in vivo. On the base of DYRK2 acting as a promising target, we further discover a highly selective DYRK2 inhibitor YK-2-69, which specifically interacts with Lys-231 and Lys-234 in the co-crystal structure. Especially, YK-2-69 exhibits more potent anti-PCa efficacy than the first-line drug enzalutamide in vivo. Meanwhile, YK-2-69 displays favorable safety properties with a maximal tolerable dose of more than 10,000 mg/kg and pharmacokinetic profiles with 56% bioavailability. In summary, we identify DYRK2 as a potential drug target and verify its critical roles in PCa. Meanwhile, we discover a highly selective DYRK2 inhibitor with favorable druggability for the treatment of PCa. The kinase DYRK2 is a known oncogene but its role in prostate cancer is unexplored. Here, the authors identify DYRK2 as a target for prostate cancer with a role in invasion and they discover a specific DYRK2 inhibitor that has good pharmacokinetics and efficacy in vivo.
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Affiliation(s)
- Kai Yuan
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, 210009, Nanjing, China.,Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, 211198, Nanjing, China
| | - Zhaoxing Li
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, 210009, Nanjing, China.,Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, 211198, Nanjing, China
| | - Wenbin Kuang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, 210009, Nanjing, China.,Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, 211198, Nanjing, China
| | - Xiao Wang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, 210009, Nanjing, China.,Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, 211198, Nanjing, China
| | - Minghui Ji
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, 210009, Nanjing, China.,Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, 211198, Nanjing, China
| | - Weijiao Chen
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, 210009, Nanjing, China.,Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, 211198, Nanjing, China
| | - Jiayu Ding
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, 210009, Nanjing, China.,Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, 211198, Nanjing, China
| | - Jiaxing Li
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, 210009, Nanjing, China.,Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, 211198, Nanjing, China
| | - Wenjian Min
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, 210009, Nanjing, China.,Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, 211198, Nanjing, China
| | - Chengliang Sun
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, 210009, Nanjing, China.,Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, 211198, Nanjing, China
| | - Xiuquan Ye
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, 210009, Nanjing, China.,Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, 211198, Nanjing, China
| | - Meiling Lu
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, 210009, Nanjing, China.,School of Life Science and Technology, China Pharmaceutical University, 211198, Nanjing, China
| | - Liping Wang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, 210009, Nanjing, China.,Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, 211198, Nanjing, China
| | - Haixia Ge
- School of Life Sciences, Huzhou University, 313000, Huzhou, China
| | - Yuzhang Jiang
- Department of Laboratory, Huai'an First People's Hospital, Nanjing Medical University, 223300, Huai'an, Jiangsu, China.
| | - Haiping Hao
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, 210009, Nanjing, China. .,Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, 211198, Nanjing, China.
| | - Yibei Xiao
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, 210009, Nanjing, China. .,Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, 211198, Nanjing, China.
| | - Peng Yang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, 210009, Nanjing, China. .,Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, 211198, Nanjing, China.
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7
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Wei T, Wang J, Liang R, Chen W, Chen Y, Ma M, He A, Du Y, Zhou W, Zhang Z, Zeng X, Wang C, Lu J, Guo X, Chen XW, Wang Y, Tian R, Xiao J, Lei X. Selective inhibition reveals the regulatory function of DYRK2 in protein synthesis and calcium entry. eLife 2022; 11:e77696. [PMID: 35439114 PMCID: PMC9113749 DOI: 10.7554/elife.77696] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 04/12/2022] [Indexed: 11/13/2022] Open
Abstract
The dual-specificity tyrosine phosphorylation-regulated kinase DYRK2 has emerged as a critical regulator of cellular processes. We took a chemical biology approach to gain further insights into its function. We developed C17, a potent small-molecule DYRK2 inhibitor, through multiple rounds of structure-based optimization guided by several co-crystallized structures. C17 displayed an effect on DYRK2 at a single-digit nanomolar IC50 and showed outstanding selectivity for the human kinome containing 467 other human kinases. Using C17 as a chemical probe, we further performed quantitative phosphoproteomic assays and identified several novel DYRK2 targets, including eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) and stromal interaction molecule 1 (STIM1). DYRK2 phosphorylated 4E-BP1 at multiple sites, and the combined treatment of C17 with AKT and MEK inhibitors showed synergistic 4E-BP1 phosphorylation suppression. The phosphorylation of STIM1 by DYRK2 substantially increased the interaction of STIM1 with the ORAI1 channel, and C17 impeded the store-operated calcium entry process. These studies collectively further expand our understanding of DYRK2 and provide a valuable tool to pinpoint its biological function.
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Affiliation(s)
- Tiantian Wei
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking UniversityBeijingChina
- Peking-Tsinghua Center for Life Sciences, Peking UniversityBeijingChina
- Academy for Advanced Interdisciplinary Studies, Peking UniversityBeijingChina
| | - Jue Wang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking UniversityBeijingChina
| | - Ruqi Liang
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking UniversityBeijingChina
- Peking-Tsinghua Center for Life Sciences, Peking UniversityBeijingChina
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking UniversityBeijingChina
| | - Wendong Chen
- SUSTech Academy for Advanced Interdisciplinary Studies, Southern University of Science and TechnologyShenzhenChina
| | - Yilan Chen
- Beijing Key Laboratory of Gene Resource and Molecular Development, Key Laboratory of Cell Proliferation and Regulation Biology, Ministry of Education, College of Life Sciences, Beijing Normal UniversityBeijingChina
| | - Mingzhe Ma
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking UniversityBeijingChina
| | - An He
- Department of Chemistry, Southern University of Science and TechnologyShenzhenChina
| | - Yifei Du
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking UniversityBeijingChina
| | - Wenjing Zhou
- Institute of Molecular Medicine, Peking UniversityBeijingChina
| | - Zhiying Zhang
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking UniversityBeijingChina
| | - Xin Zeng
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking UniversityBeijingChina
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking UniversityBeijingChina
| | - Chu Wang
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking UniversityBeijingChina
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking UniversityBeijingChina
| | - Jin Lu
- Peking University Institute of Hematology, People’s HospitalBeijingChina
- Collaborative Innovation Center of HematologySuzhouChina
| | - Xing Guo
- Life Sciences Institute, Zhejiang UniversityHangzhouChina
| | - Xiao-Wei Chen
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking UniversityBeijingChina
- Institute of Molecular Medicine, Peking UniversityBeijingChina
| | - Youjun Wang
- Beijing Key Laboratory of Gene Resource and Molecular Development, Key Laboratory of Cell Proliferation and Regulation Biology, Ministry of Education, College of Life Sciences, Beijing Normal UniversityBeijingChina
| | - Ruijun Tian
- SUSTech Academy for Advanced Interdisciplinary Studies, Southern University of Science and TechnologyShenzhenChina
- Beijing Key Laboratory of Gene Resource and Molecular Development, Key Laboratory of Cell Proliferation and Regulation Biology, Ministry of Education, College of Life Sciences, Beijing Normal UniversityBeijingChina
| | - Junyu Xiao
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking UniversityBeijingChina
- Peking-Tsinghua Center for Life Sciences, Peking UniversityBeijingChina
- Academy for Advanced Interdisciplinary Studies, Peking UniversityBeijingChina
- Beijing Advanced Innovation Center for Genomics (ICG), Peking UniversityBeijingChina
| | - Xiaoguang Lei
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking UniversityBeijingChina
- Peking-Tsinghua Center for Life Sciences, Peking UniversityBeijingChina
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking UniversityBeijingChina
- Institute for Cancer Research, Shenzhen Bay LaboratoryShenzhenChina
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8
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Kim SH, Yu HS, Huh S, Kang UG, Kim YS. Electroconvulsive seizure inhibits the mTOR signaling pathway via AMPK in the rat frontal cortex. Psychopharmacology (Berl) 2022; 239:443-454. [PMID: 34716784 DOI: 10.1007/s00213-021-06015-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 10/13/2021] [Indexed: 01/23/2023]
Abstract
RATIONALE Accumulating evidence indicates critical involvement of mammalian target of rapamycin (mTOR) in the treatment of depressive disorders, epilepsy, and neurodegenerative disorders through its signal transduction mechanisms related to protein translation, autophagy, and synaptic remodeling. Electroconvulsive seizure (ECS) treatment is a potent antidepressive, anti-convulsive, and neuroprotective therapeutic modality; however, its effects on mTOR signaling have not yet been clarified. METHODS The effect of ECS on the mTOR complex 1 (mTORC1) pathway was investigated in the rat frontal cortex. ECS or sham treatment was administered once per day for 10 days (E10X or sham), and compound C was administered through the intracerebroventricular cannula. Changes in mTORC1-associated signaling molecules and their interactions were analyzed. RESULTS E10X reduced phosphorylation of mTOR downstream substrates, including p70S6K, S6, and 4E-BP1, and increased inhibitory phosphorylation of mTOR at Thr2446 compared to the sham group in the rat frontal cortex, indicating E10X-induced inhibition of mTORC1 activity. Akt and ERK1/2, upstream kinases that activate mTORC1, were not inhibited; however, AMPK, which can inhibit mTORC1, was activated. AMPK-responsive phosphorylation of Raptor at Ser792 and TSC2 at Ser1387 inhibiting mTORC1 was increased by E10X. Moreover, intrabrain inhibition of AMPK restored E10X-induced changes in the phosphorylation of S6, Raptor, and TSC2, indicating mediation of AMPK in E10X-induced mTOR inhibition. CONCLUSIONS Repeated ECS treatments inhibit mTORC1 signaling by interactive crosstalk between mTOR and AMPK pathways, which could play important roles in the action of ECS via autophagy induction.
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Affiliation(s)
- Se Hyun Kim
- Department of Psychiatry, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea.
| | - Hyun Sook Yu
- Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
| | - Seonghoo Huh
- Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
| | - Ung Gu Kang
- Department of Psychiatry, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea.,Institute of Human Behavioral Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Yong Sik Kim
- Department of Psychiatry, NowonEulji Medical Center, Eulji University, Seoul, Republic of Korea
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9
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Control of the eIF4E activity: structural insights and pharmacological implications. Cell Mol Life Sci 2021; 78:6869-6885. [PMID: 34541613 PMCID: PMC8558276 DOI: 10.1007/s00018-021-03938-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 08/28/2021] [Accepted: 09/08/2021] [Indexed: 12/17/2022]
Abstract
The central role of eukaryotic translation initiation factor 4E (eIF4E) in controlling mRNA translation has been clearly assessed in the last decades. eIF4E function is essential for numerous physiological processes, such as protein synthesis, cellular growth and differentiation; dysregulation of its activity has been linked to ageing, cancer onset and progression and neurodevelopmental disorders, such as autism spectrum disorder (ASD) and Fragile X Syndrome (FXS). The interaction between eIF4E and the eukaryotic initiation factor 4G (eIF4G) is crucial for the assembly of the translational machinery, the initial step of mRNA translation. A well-characterized group of proteins, named 4E-binding proteins (4E-BPs), inhibits the eIF4E–eIF4G interaction by competing for the same binding site on the eIF4E surface. 4E-BPs and eIF4G share a single canonical motif for the interaction with a conserved hydrophobic patch of eIF4E. However, a second non-canonical and not conserved binding motif was recently detected for eIF4G and several 4E-BPs. Here, we review the structural features of the interaction between eIF4E and its molecular partners eIF4G and 4E-BPs, focusing on the implications of the recent structural and biochemical evidence for the development of new therapeutic strategies. The design of novel eIF4E-targeting molecules that inhibit translation might provide new avenues for the treatment of several conditions.
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10
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Le Phan TH, Park SY, Jung HJ, Kim MW, Cho E, Shim KS, Shin E, Yoon JH, Maeng HJ, Kang JH, Oh SH. The Role of Processed Aloe vera Gel in Intestinal Tight Junction: An In Vivo and In Vitro Study. Int J Mol Sci 2021; 22:ijms22126515. [PMID: 34204534 PMCID: PMC8235210 DOI: 10.3390/ijms22126515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 06/14/2021] [Indexed: 11/25/2022] Open
Abstract
Leaky gut is a condition of increased paracellular permeability of the intestine due to compromised tight junction barriers. In recent years, this affliction has drawn the attention of scientists from different fields, as a myriad of studies prosecuted it to be the silent culprit of various immune diseases. Due to various controversies surrounding its culpability in the clinic, approaches to leaky gut are restricted in maintaining a healthy lifestyle, avoiding irritating factors, and practicing alternative medicine, including the consumption of supplements. In the current study, we investigate the tight junction-modulating effects of processed Aloe vera gel (PAG), comprising 5–400-kD polysaccharides as the main components. Our results show that oral treatment of 143 mg/kg PAG daily for 10 days improves the age-related leaky gut condition in old mice, by reducing their individual urinal lactulose/mannitol (L/M) ratio. In concordance with in vivo experiments, PAG treatment at dose 400 μg/mL accelerated the polarization process of Caco-2 monolayers. The underlying mechanism was attributed to enhancement in the expression of intestinal tight junction-associated scaffold protein zonula occludens (ZO)-1 at the translation level. This was induced by activation of the MAPK/ERK signaling pathway, which inhibits the translation repressor 4E-BP1. In conclusion, we propose that consuming PAG as a complementary food has the potential to benefit high-risk patients.
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Affiliation(s)
- Thu Han Le Phan
- College of Pharmacy, Gachon University, Incheon 21936, Korea; (T.H.L.P.); (H.J.J.); (J.-H.Y.); (H.-J.M.)
| | - Se Yong Park
- College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea; (S.Y.P.); (M.W.K.)
| | - Hyun Jin Jung
- College of Pharmacy, Gachon University, Incheon 21936, Korea; (T.H.L.P.); (H.J.J.); (J.-H.Y.); (H.-J.M.)
| | - Min Woo Kim
- College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea; (S.Y.P.); (M.W.K.)
| | - Eunae Cho
- Univera Co., Ltd., Seoul 04782, Korea; (E.C.); (K.-S.S.); (E.S.)
| | - Kyu-Suk Shim
- Univera Co., Ltd., Seoul 04782, Korea; (E.C.); (K.-S.S.); (E.S.)
| | - Eunju Shin
- Univera Co., Ltd., Seoul 04782, Korea; (E.C.); (K.-S.S.); (E.S.)
| | - Jin-Ha Yoon
- College of Pharmacy, Gachon University, Incheon 21936, Korea; (T.H.L.P.); (H.J.J.); (J.-H.Y.); (H.-J.M.)
| | - Han-Joo Maeng
- College of Pharmacy, Gachon University, Incheon 21936, Korea; (T.H.L.P.); (H.J.J.); (J.-H.Y.); (H.-J.M.)
| | - Ju-Hee Kang
- College of Pharmacy, Gachon University, Incheon 21936, Korea; (T.H.L.P.); (H.J.J.); (J.-H.Y.); (H.-J.M.)
- Correspondence: (J.-H.K.); (S.H.O.); Tel./Fax: +82-32-820-4929 (S.H.O.)
| | - Seung Hyun Oh
- College of Pharmacy, Gachon University, Incheon 21936, Korea; (T.H.L.P.); (H.J.J.); (J.-H.Y.); (H.-J.M.)
- Correspondence: (J.-H.K.); (S.H.O.); Tel./Fax: +82-32-820-4929 (S.H.O.)
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11
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Alboushi L, Hackett AP, Naeli P, Bakhti M, Jafarnejad SM. Multifaceted control of mRNA translation machinery in cancer. Cell Signal 2021; 84:110037. [PMID: 33975011 DOI: 10.1016/j.cellsig.2021.110037] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 05/06/2021] [Indexed: 12/15/2022]
Abstract
The mRNA translation machinery is tightly regulated through several, at times overlapping, mechanisms that modulate its efficiency and accuracy. Due to their fast rate of growth and metabolism, cancer cells require an excessive amount of mRNA translation and protein synthesis. However, unfavorable conditions, such as hypoxia, amino acid starvation, and oxidative stress, which are abundant in cancer, as well as many anti-cancer treatments inhibit mRNA translation. Cancer cells adapt to the various internal and environmental stresses by employing specialised transcript-specific translation to survive and gain a proliferative advantage. We will highlight the major signaling pathways and mechanisms of translation that regulate the global or mRNA-specific translation in response to the intra- or extra-cellular signals and stresses that are key components in the process of tumourigenesis.
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Affiliation(s)
- Lilas Alboushi
- Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, UK
| | - Angela P Hackett
- Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, UK
| | - Parisa Naeli
- Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, UK
| | - Mostafa Bakhti
- Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Seyed Mehdi Jafarnejad
- Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, UK.
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12
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Jia JJ, Lahr RM, Solgaard MT, Moraes BJ, Pointet R, Yang AD, Celucci G, Graber TE, Hoang HD, Niklaus M, Pena IA, Hollensen AK, Smith EM, Chaker-Margot M, Anton L, Dajadian C, Livingstone M, Hearnden J, Wang XD, Yu Y, Maier T, Damgaard CK, Berman AJ, Alain T, Fonseca BD. mTORC1 promotes TOP mRNA translation through site-specific phosphorylation of LARP1. Nucleic Acids Res 2021; 49:3461-3489. [PMID: 33398329 PMCID: PMC8034618 DOI: 10.1093/nar/gkaa1239] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 11/29/2020] [Accepted: 12/15/2020] [Indexed: 02/06/2023] Open
Abstract
LARP1 is a key repressor of TOP mRNA translation. It binds the m7Gppp cap moiety and the adjacent 5'TOP motif of TOP mRNAs, thus impeding the assembly of the eIF4F complex on these transcripts. mTORC1 controls TOP mRNA translation via LARP1, but the details of the mechanism are unclear. Herein we elucidate the mechanism by which mTORC1 controls LARP1's translation repression activity. We demonstrate that mTORC1 phosphorylates LARP1 in vitro and in vivo, activities that are efficiently inhibited by rapamycin and torin1. We uncover 26 rapamycin-sensitive phospho-serine and -threonine residues on LARP1 that are distributed in 7 clusters. Our data show that phosphorylation of a cluster of residues located proximally to the m7Gppp cap-binding DM15 region is particularly sensitive to rapamycin and regulates both the RNA-binding and the translation inhibitory activities of LARP1. Our results unravel a new model of translation control in which the La module (LaMod) and DM15 region of LARP1, both of which can directly interact with TOP mRNA, are differentially regulated: the LaMod remains constitutively bound to PABP (irrespective of the activation status of mTORC1), while the C-terminal DM15 'pendular hook' engages the TOP mRNA 5'-end to repress translation, but only in conditions of mTORC1 inhibition.
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Affiliation(s)
- Jian-Jun Jia
- Children's Hospital of Eastern Ontario (CHEO) Research Institute, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada
| | - Roni M Lahr
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Michael T Solgaard
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Bruno J Moraes
- GABBA PhD Program, Abel Salazar Biomedical Sciences Institute, University of Porto, Porto, Portugal
- PrimerGen Ltd, Viseu, Portugal
| | - Roberta Pointet
- Children's Hospital of Eastern Ontario (CHEO) Research Institute, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada
| | - An-Dao Yang
- Children's Hospital of Eastern Ontario (CHEO) Research Institute, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada
| | - Giovanna Celucci
- Children's Hospital of Eastern Ontario (CHEO) Research Institute, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada
| | - Tyson E Graber
- Children's Hospital of Eastern Ontario (CHEO) Research Institute, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada
| | - Huy-Dung Hoang
- Children's Hospital of Eastern Ontario (CHEO) Research Institute, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada
| | - Marius R Niklaus
- Children's Hospital of Eastern Ontario (CHEO) Research Institute, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada
| | - Izabella A Pena
- Children's Hospital of Eastern Ontario (CHEO) Research Institute, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada
| | - Anne K Hollensen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Ewan M Smith
- Cancer Research UK Beatson Institute, Glasgow, UK
| | | | - Leonie Anton
- Biozentrum, University of Basel, Basel, Switzerland
| | - Christopher Dajadian
- Department of Biochemistry, Rosalind and Morris Goodman Cancer Centre, McGill University, Montréal, Canada
| | - Mark Livingstone
- Department of Biochemistry, Rosalind and Morris Goodman Cancer Centre, McGill University, Montréal, Canada
| | - Jaclyn Hearnden
- Department of Biochemistry, Rosalind and Morris Goodman Cancer Centre, McGill University, Montréal, Canada
| | - Xu-Dong Wang
- Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX, USA
| | - Yonghao Yu
- Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX, USA
| | - Timm Maier
- Biozentrum, University of Basel, Basel, Switzerland
| | - Christian K Damgaard
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Andrea J Berman
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Tommy Alain
- Children's Hospital of Eastern Ontario (CHEO) Research Institute, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada
| | - Bruno D Fonseca
- Children's Hospital of Eastern Ontario (CHEO) Research Institute, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada
- PrimerGen Ltd, Viseu, Portugal
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13
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Atilano ML, Grönke S, Niccoli T, Kempthorne L, Hahn O, Morón-Oset J, Hendrich O, Dyson M, Adams ML, Hull A, Salcher-Konrad MT, Monaghan A, Bictash M, Glaria I, Isaacs AM, Partridge L. Enhanced insulin signalling ameliorates C9orf72 hexanucleotide repeat expansion toxicity in Drosophila. eLife 2021; 10:e58565. [PMID: 33739284 PMCID: PMC8007214 DOI: 10.7554/elife.58565] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 03/09/2021] [Indexed: 12/14/2022] Open
Abstract
G4C2 repeat expansions within the C9orf72 gene are the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The repeats undergo repeat-associated non-ATG translation to generate toxic dipeptide repeat proteins. Here, we show that insulin/IGF signalling is reduced in fly models of C9orf72 repeat expansion using RNA sequencing of adult brain. We further demonstrate that activation of insulin/IGF signalling can mitigate multiple neurodegenerative phenotypes in flies expressing either expanded G4C2 repeats or the toxic dipeptide repeat protein poly-GR. Levels of poly-GR are reduced when components of the insulin/IGF signalling pathway are genetically activated in the diseased flies, suggesting a mechanism of rescue. Modulating insulin signalling in mammalian cells also lowers poly-GR levels. Remarkably, systemic injection of insulin improves the survival of flies expressing G4C2 repeats. Overall, our data suggest that modulation of insulin/IGF signalling could be an effective therapeutic approach against C9orf72 ALS/FTD.
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Affiliation(s)
- Magda L Atilano
- Department of Genetics, Evolution and Environment, Institute of Healthy AgeingLondonUnited Kingdom
- UK Dementia Research Institute at UCLLondonUnited Kingdom
| | | | - Teresa Niccoli
- Department of Genetics, Evolution and Environment, Institute of Healthy AgeingLondonUnited Kingdom
- UK Dementia Research Institute at UCLLondonUnited Kingdom
| | - Liam Kempthorne
- UK Dementia Research Institute at UCLLondonUnited Kingdom
- Department of Neurodegenerative Disease, UCL Institute of NeurologyLondonUnited Kingdom
| | - Oliver Hahn
- Max Planck Institute for Biology of AgeingCologneGermany
| | | | | | - Miranda Dyson
- Department of Genetics, Evolution and Environment, Institute of Healthy AgeingLondonUnited Kingdom
- UK Dementia Research Institute at UCLLondonUnited Kingdom
| | - Mirjam Lisette Adams
- Department of Genetics, Evolution and Environment, Institute of Healthy AgeingLondonUnited Kingdom
- UK Dementia Research Institute at UCLLondonUnited Kingdom
| | - Alexander Hull
- Department of Genetics, Evolution and Environment, Institute of Healthy AgeingLondonUnited Kingdom
| | - Marie-Therese Salcher-Konrad
- UK Dementia Research Institute at UCLLondonUnited Kingdom
- Department of Neurodegenerative Disease, UCL Institute of NeurologyLondonUnited Kingdom
| | - Amy Monaghan
- Alzheimer's Research United Kingdom UCL Drug Discovery Institute, University College LondonLondonUnited Kingdom
| | - Magda Bictash
- Alzheimer's Research United Kingdom UCL Drug Discovery Institute, University College LondonLondonUnited Kingdom
| | - Idoia Glaria
- UK Dementia Research Institute at UCLLondonUnited Kingdom
- Department of Neurodegenerative Disease, UCL Institute of NeurologyLondonUnited Kingdom
| | - Adrian M Isaacs
- UK Dementia Research Institute at UCLLondonUnited Kingdom
- Department of Neurodegenerative Disease, UCL Institute of NeurologyLondonUnited Kingdom
| | - Linda Partridge
- Department of Genetics, Evolution and Environment, Institute of Healthy AgeingLondonUnited Kingdom
- Max Planck Institute for Biology of AgeingCologneGermany
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14
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Correa-Sáez A, Jiménez-Izquierdo R, Garrido-Rodríguez M, Morrugares R, Muñoz E, Calzado MA. Updating dual-specificity tyrosine-phosphorylation-regulated kinase 2 (DYRK2): molecular basis, functions and role in diseases. Cell Mol Life Sci 2020; 77:4747-4763. [PMID: 32462403 PMCID: PMC7658070 DOI: 10.1007/s00018-020-03556-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 05/15/2020] [Accepted: 05/18/2020] [Indexed: 12/15/2022]
Abstract
Members of the dual-specificity tyrosine-regulated kinase (DYRKs) subfamily possess a distinctive capacity to phosphorylate tyrosine, serine, and threonine residues. Among the DYRK class II members, DYRK2 is considered a unique protein due to its role in disease. According to the post-transcriptional and post-translational modifications, DYRK2 expression greatly differs among human tissues. Regarding its mechanism of action, this kinase performs direct phosphorylation on its substrates or acts as a priming kinase, enabling subsequent substrate phosphorylation by GSK3β. Moreover, DYRK2 acts as a scaffold for the EDVP E3 ligase complex during the G2/M phase of cell cycle. DYRK2 functions such as cell survival, cell development, cell differentiation, proteasome regulation, and microtubules were studied in complete detail in this review. We have also gathered available information from different bioinformatic resources to show DYRK2 interactome, normal and tumoral tissue expression, and recurrent cancer mutations. Then, here we present an innovative approach to clarify DYRK2 functionality and importance. DYRK2 roles in diseases have been studied in detail, highlighting this kinase as a key protein in cancer development. First, DYRK2 regulation of c-Jun, c-Myc, Rpt3, TERT, and katanin p60 reveals the implication of this kinase in cell-cycle-mediated cancer development. Additionally, depletion of this kinase correlated with reduced apoptosis, with consequences on cancer patient response to chemotherapy. Other functions like cancer stem cell formation and epithelial-mesenchymal transition regulation are also controlled by DYRK2. Furthermore, the pharmacological modulation of this protein by different inhibitors (harmine, curcumine, LDN192960, and ID-8) has enabled to clarify DYRK2 functionality.
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Affiliation(s)
- Alejandro Correa-Sáez
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Avda. Menéndez Pidal s/n., 14004, Córdoba, Spain
- Departamento de Biología Celular, Fisiología E Inmunología, Universidad de Córdoba, Córdoba, Spain
- Hospital Universitario Reina Sofía, Córdoba, Spain
| | - Rafael Jiménez-Izquierdo
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Avda. Menéndez Pidal s/n., 14004, Córdoba, Spain
- Departamento de Biología Celular, Fisiología E Inmunología, Universidad de Córdoba, Córdoba, Spain
- Hospital Universitario Reina Sofía, Córdoba, Spain
| | - Martín Garrido-Rodríguez
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Avda. Menéndez Pidal s/n., 14004, Córdoba, Spain
- Departamento de Biología Celular, Fisiología E Inmunología, Universidad de Córdoba, Córdoba, Spain
- Hospital Universitario Reina Sofía, Córdoba, Spain
| | - Rosario Morrugares
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Avda. Menéndez Pidal s/n., 14004, Córdoba, Spain
- Departamento de Biología Celular, Fisiología E Inmunología, Universidad de Córdoba, Córdoba, Spain
- Hospital Universitario Reina Sofía, Córdoba, Spain
| | - Eduardo Muñoz
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Avda. Menéndez Pidal s/n., 14004, Córdoba, Spain
- Departamento de Biología Celular, Fisiología E Inmunología, Universidad de Córdoba, Córdoba, Spain
- Hospital Universitario Reina Sofía, Córdoba, Spain
| | - Marco A Calzado
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Avda. Menéndez Pidal s/n., 14004, Córdoba, Spain.
- Departamento de Biología Celular, Fisiología E Inmunología, Universidad de Córdoba, Córdoba, Spain.
- Hospital Universitario Reina Sofía, Córdoba, Spain.
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15
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Hamza GM, Bergo VB, Mamaev S, Wojchowski DM, Toran P, Worsfold CR, Castaldi MP, Silva JC. Affinity-Bead Assisted Mass Spectrometry (Affi-BAMS): A Multiplexed Microarray Platform for Targeted Proteomics. Int J Mol Sci 2020; 21:E2016. [PMID: 32188029 PMCID: PMC7139916 DOI: 10.3390/ijms21062016] [Citation(s) in RCA: 4] [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: 02/09/2020] [Revised: 03/10/2020] [Accepted: 03/13/2020] [Indexed: 02/06/2023] Open
Abstract
The ability to quantitatively probe diverse panels of proteins and their post-translational modifications (PTMs) across multiple samples would aid a broad spectrum of biological, biochemical and pharmacological studies. We report a novel, microarray analytical technology that combines immuno-affinity capture with Matrix Assisted Laser Desorption Ionization Mass Spectrometry (MALDI MS), which is capable of supporting highly multiplexed, targeted proteomic assays. Termed "Affinity-Bead Assisted Mass Spectrometry" (Affi-BAMS), this LC-free technology enables development of highly specific and customizable assay panels for simultaneous profiling of multiple proteins and PTMs. While affinity beads have been used previously in combination with MS, the Affi-BAMS workflow uses enrichment on a single bead that contains one type of antibody, generally capturing a single analyte (protein or PTM) while having enough binding capacity to enable quantification within approximately 3 orders of magnitude. The multiplexing capability is achieved by combining Affi-BAMS beads with different protein specificities. To enable screening of bead-captured analytes by MS, we further developed a novel method of performing spatially localized elution of targets from individual beads arrayed on a microscope slide. The resulting arrays of micro spots contain highly concentrated analytes localized within 0.5 mm diameter spots that can be directly measured using MALDI MS. While both intact proteins and protein fragments can be monitored by Affi-BAMS, we initially focused on applying this technology for bottom-up proteomics to enable screening of hundreds of samples per day by combining the robust magnetic bead-based workflow with the high throughput nature of MALDI MS acquisition. To demonstrate the variety of applications and robustness of Affi-BAMS, several studies are presented that focus on the response of 4EBP1, RPS6, ERK1/ERK2, mTOR, Histone H3 and C-MET to stimuli including rapamycin, H2O2, EPO, SU11274, Staurosporine and Vorinostat.
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Affiliation(s)
- Ghaith M. Hamza
- Discovery Sciences, BioPharmaceutical R&D, AstraZeneca, Boston, MA 02451, USA; (G.M.H.); (M.P.C.)
- Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH 03824, USA; (D.M.W.); (P.T.)
| | - Vladislav B. Bergo
- Adeptrix Corporation, Beverly, MA 01915, USA; (V.B.B.); (S.M.); (C.R.W.)
| | - Sergey Mamaev
- Adeptrix Corporation, Beverly, MA 01915, USA; (V.B.B.); (S.M.); (C.R.W.)
| | - Don M. Wojchowski
- Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH 03824, USA; (D.M.W.); (P.T.)
| | - Paul Toran
- Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH 03824, USA; (D.M.W.); (P.T.)
| | | | - M. Paola Castaldi
- Discovery Sciences, BioPharmaceutical R&D, AstraZeneca, Boston, MA 02451, USA; (G.M.H.); (M.P.C.)
| | - Jeffrey C. Silva
- Adeptrix Corporation, Beverly, MA 01915, USA; (V.B.B.); (S.M.); (C.R.W.)
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16
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Sun R, Cheng E, Velásquez C, Chang Y, Moore PS. Mitosis-related phosphorylation of the eukaryotic translation suppressor 4E-BP1 and its interaction with eukaryotic translation initiation factor 4E (eIF4E). J Biol Chem 2019; 294:11840-11852. [PMID: 31201269 PMCID: PMC6682726 DOI: 10.1074/jbc.ra119.008512] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 06/10/2019] [Indexed: 11/22/2022] Open
Abstract
Eukaryotic translation initiation factor 4E (eIF4E)–binding protein 1 (4E-BP1) inhibits cap-dependent translation in eukaryotes by competing with eIF4G for an interaction with eIF4E. Phosphorylation at Ser-83 of 4E-BP1 occurs during mitosis through the activity of cyclin-dependent kinase 1 (CDK1)/cyclin B rather than through canonical mTOR kinase activity. Here, we investigated the interaction of eIF4E with 4E-BP1 or eIF4G during interphase and mitosis. We observed that 4E-BP1 and eIF4G bind eIF4E at similar levels during interphase and mitosis. The most highly phosphorylated mitotic 4E-BP1 isoform (δ) did not interact with eIF4E, whereas a distinct 4E-BP1 phospho-isoform, EB-γ, phosphorylated at Thr-70, Ser-83, and Ser-101, bound to eIF4E during mitosis. Two-dimensional gel electrophoretic analysis corroborated the identity of the phosphorylation marks on the eIF4E-bound 4E-BP1 isoforms and uncovered a population of phosphorylated 4E-BP1 molecules lacking Thr-37/Thr-46–priming phosphorylation. Moreover, proximity ligation assays for phospho-4E-BP1 and eIF4E revealed different in situ interactions during interphase and mitosis. The eIF4E:eIF4G interaction was not inhibited but rather increased in mitotic cells, consistent with active translation initiation during mitosis. Phosphodefective substitution of 4E-BP1 at Ser-83 did not change global translation or individual mRNA translation profiles as measured by single-cell nascent protein synthesis and eIF4G RNA immunoprecipitation sequencing. Mitotic 5′-terminal oligopyrimidine RNA translation was active and, unlike interphase translation, resistant to mTOR inhibition. Our findings reveal the phosphorylation profiles of 4E-BP1 isoforms and their interactions with eIF4E throughout the cell cycle and indicate that 4E-BP1 does not specifically inhibit translation initiation during mitosis.
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Affiliation(s)
- Rui Sun
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania 15213.,Cancer Virology Program, UPMC Hillman Cancer Center, Pittsburgh, Pennsylvania 15213
| | - Erdong Cheng
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania 15213.,Cancer Virology Program, UPMC Hillman Cancer Center, Pittsburgh, Pennsylvania 15213
| | - Celestino Velásquez
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania 15213.,Cancer Virology Program, UPMC Hillman Cancer Center, Pittsburgh, Pennsylvania 15213
| | - Yuan Chang
- Cancer Virology Program, UPMC Hillman Cancer Center, Pittsburgh, Pennsylvania 15213 .,Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213
| | - Patrick S Moore
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania 15213 .,Cancer Virology Program, UPMC Hillman Cancer Center, Pittsburgh, Pennsylvania 15213
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17
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Mitchell DC, Menon A, Garner AL. Chemoproteomic Profiling Uncovers CDK4-Mediated Phosphorylation of the Translational Suppressor 4E-BP1. Cell Chem Biol 2019; 26:980-990.e8. [PMID: 31056462 DOI: 10.1016/j.chembiol.2019.03.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 02/04/2019] [Accepted: 03/25/2019] [Indexed: 01/03/2023]
Abstract
Recent estimates of the human proteome suggest there are ∼20,000 protein-coding genes, the protein products of which contain >145,000 phosphosites. Unfortunately, in-depth examination of the human phosphoproteome has outpaced the ability to annotate the kinases that mediate these post-translational modifications. To obtain actionable information about phosphorylation-driven signaling cascades, it is essential to identify the kinases responsible for phosphorylating sites that differ across disease states. To fill in these gaps we have developed an unbiased, chemoproteomic approach for identifying high-confidence kinase-substrate interactions with phosphosite specificity. Using this assay, we uncovered the role of cyclin-dependent kinase 4 (CDK4), a clinically validated kinase important for cell-cycle progression, in regulating cap-dependent translation via phosphorylation of the tumor suppressor 4E-BP1. The discovery of this signaling axis sheds light on the mechanisms by which CDK4/6 inhibitors control cell proliferation and constitutes a successful example of kinase discovery using an activity-based, kinase-directed probe.
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Affiliation(s)
- Dylan C Mitchell
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Arya Menon
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI 48109, USA
| | - Amanda L Garner
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI 48109, USA; Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI 48109, USA.
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18
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Abstract
Translation is a key step in the regulation of gene expression and one of the most energy-consuming processes in the cell. In response to various stimuli, multiple signaling pathways converge on the translational machinery to regulate its function. To date, the roles of phosphoinositide 3-kinase (PI3K)/AKT and the mitogen-activated protein kinase (MAPK) pathways in the regulation of translation are among the best understood. Both pathways engage the mechanistic target of rapamycin (mTOR) to regulate a variety of components of the translational machinery. While these pathways regulate protein synthesis in homeostasis, their dysregulation results in aberrant translation leading to human diseases, including diabetes, neurological disorders, and cancer. Here we review the roles of the PI3K/AKT and MAPK pathways in the regulation of mRNA translation. We also highlight additional signaling mechanisms that have recently emerged as regulators of the translational apparatus.
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19
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Lamberti G, Brighi N, Maggio I, Manuzzi L, Peterle C, Ambrosini V, Ricci C, Casadei R, Campana D. The Role of mTOR in Neuroendocrine Tumors: Future Cornerstone of a Winning Strategy? Int J Mol Sci 2018; 19:ijms19030747. [PMID: 29509701 PMCID: PMC5877608 DOI: 10.3390/ijms19030747] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 02/28/2018] [Accepted: 03/05/2018] [Indexed: 12/13/2022] Open
Abstract
The mechanistic target of rapamycin (mTOR) is part of the phosphoinositide-3-kinase (PI3K)/protein kinase B (AkT)/mTOR pathway and owes its name to the inhibitory effect of rapamycin. The mTOR has a central converging role for many cell functions, serving as a sensor for extracellular signals from energy status and nutrients availability, growth factors, oxygen and stress. Thus, it also modulates switch to anabolic processes (protein and lipid synthesis) and autophagy, in order to regulate cell growth and proliferation. Given its functions in the cell, its deregulation is implicated in many human diseases, including cancer. Its predominant role in tumorigenesis and progression of neuroendocrine tumors (NETs), in particular, has been demonstrated in preclinical studies and late clinical trials. mTOR inhibition by everolimus is an established therapeutic target in NETs, but there are no identified predictive or prognostic factors. This review is focused on the role of mTOR and everolimus in NETs, from preclinical studies to major clinical trials, and future perspectives involving mTOR in the treatment of NETs.
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Affiliation(s)
- Giuseppe Lamberti
- Department of Experimental, Diagnostic and Specialty Medicine, S.Orsola-Malpighi University Hospital, 40138 Bologna, Italy.
| | - Nicole Brighi
- Department of Experimental, Diagnostic and Specialty Medicine, S.Orsola-Malpighi University Hospital, 40138 Bologna, Italy.
| | - Ilaria Maggio
- Department of Experimental, Diagnostic and Specialty Medicine, S.Orsola-Malpighi University Hospital, 40138 Bologna, Italy.
| | - Lisa Manuzzi
- Department of Experimental, Diagnostic and Specialty Medicine, S.Orsola-Malpighi University Hospital, 40138 Bologna, Italy.
| | - Chiara Peterle
- Department of Experimental, Diagnostic and Specialty Medicine, S.Orsola-Malpighi University Hospital, 40138 Bologna, Italy.
| | - Valentina Ambrosini
- Nuclear Medicine Unit, Medicina Nucleare Metropolitana, S.Orsola-Malpighi University Hospital, 40138 Bologna, Italy.
| | - Claudio Ricci
- Department of Medical and Surgical Sciences, S.Orsola-Malpighi University Hospital, 40138 Bologna, Italy.
| | - Riccardo Casadei
- Department of Medical and Surgical Sciences, S.Orsola-Malpighi University Hospital, 40138 Bologna, Italy.
| | - Davide Campana
- Department of Medical and Surgical Sciences, S.Orsola-Malpighi University Hospital, 40138 Bologna, Italy.
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20
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Severance AL, Latham KE. PLK1 regulates spindle association of phosphorylated eukaryotic translation initiation factor 4E-binding protein and spindle function in mouse oocytes. Am J Physiol Cell Physiol 2017; 313:C501-C515. [PMID: 28794108 PMCID: PMC5792166 DOI: 10.1152/ajpcell.00075.2017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 08/03/2017] [Accepted: 08/04/2017] [Indexed: 11/22/2022]
Abstract
Oocyte meiotic spindles are associated with spindle-enriched mRNAs, phosphorylated ribosome protein S6, and phosphorylated variants of the key translational regulator, eukaryotic translation initiation factor 4E-binding protein 1 (eIF4E-BP1), consistent with translational control of localized mRNAs by eIF4E-BP1 in facilitating spindle formation and stability. Using specific kinase inhibitors, we determined which kinases regulate phosphorylation status of eIF4E-BP1 associated with meiotic spindles in mouse oocytes and effects of kinase inhibition on chromosome congression and spindle formation. Neither ataxia telangiectasia-mutated kinase nor mechanistic target of rapamycin inhibition significantly affected phosphorylation status of spindle-associated eIF4E-BP1 at the phosphorylation sites examined. Spindle-associated phospho-eIF4E-BP1, spindle formation, and chromosome congression were strongly disrupted by polo-like kinase I (PLK1) inhibition at both metaphase I (MI) and MII. In addition, direct inhibition of eIF4E-BP1 via 4EGI led to spindle defects at MI, indicating a direct role for eIF4E-BP1 phosphorylation in meiotic spindle formation. PLK1 also regulated microtubule dynamics throughout the ooplasm, indicating likely coordination between spindle dynamics and broader ooplasm cytoskeletal dynamics. Because diverse upstream signaling pathways converge on PLK1, these results implicate PLK1 as a major regulatory nexus coupling endogenous and exogenous signals via eIF4E-BP1 to the regulation of spindle formation and stability.
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Affiliation(s)
- Ashley L Severance
- Reproductive and Developmental Sciences Program, Michigan State University , East Lansing, Michigan
- Genetics Graduate Program, Michigan State University , East Lansing, Michigan
| | - Keith E Latham
- Reproductive and Developmental Sciences Program, Michigan State University , East Lansing, Michigan
- Genetics Graduate Program, Michigan State University , East Lansing, Michigan
- Department of Animal Science, Michigan State University , East Lansing, Michigan ; and
- Department of Obstetrics, Gynecology, and Reproductive Biology, Michigan State University , East Lansing, Michigan
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21
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Reappraisal to the study of 4E-BP1 as an mTOR substrate – A normative critique. Eur J Cell Biol 2017; 96:325-336. [DOI: 10.1016/j.ejcb.2017.03.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 03/31/2017] [Accepted: 03/31/2017] [Indexed: 12/20/2022] Open
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22
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Seo MK, Choi CM, McIntyre RS, Cho HY, Lee CH, Mansur RB, Lee Y, Lee JH, Kim YH, Park SW, Lee JG. Effects of escitalopram and paroxetine on mTORC1 signaling in the rat hippocampus under chronic restraint stress. BMC Neurosci 2017; 18:39. [PMID: 28446154 PMCID: PMC5405541 DOI: 10.1186/s12868-017-0357-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 04/20/2017] [Indexed: 12/28/2022] Open
Abstract
Background Recent studies have suggested that the activation of mammalian target of rapamycin (mTOR) signaling may be related to antidepressant action. Therefore, the present study evaluated whether antidepressant drugs would exert differential effects on mTOR signaling in the rat hippocampus under conditions of chronic restraint stress. Male Sprague–Dawley rats were subjected to restraint stress for 6 h/days for 21 days with either escitalopram (10 mg/kg) or paroxetine (10 mg/kg) administered after the chronic stress procedure. Western blot analyses were used to assess changes in the levels of phospho-Ser2448-mTOR, phospho-Thr37/46-4E-BP-1, phospho-Thr389-p70S6 K, phospho-Ser422-eIF4B, phospho-Ser240/244-S6, phospho-Ser473-Akt, and phospho-Thr202/Tyr204-ERK in the hippocampus. Results Chronic restraint stress significantly decreased the levels of phospho-mTOR complex 1 (mTORC1), phospho-4E-BP-1, phospho-p70S6 K, phospho-eIF4B, phospho-S6, phospho-Akt, and phospho-ERK (p < 0.05); the administration of escitalopram and paroxetine increased the levels of all these proteins (p < 0.05 or 0.01). Additionally, chronic restraint stress reduced phospho-mTORC1 signaling activities in general, while escitalopram and paroxetine prevented these changes in phospho-mTORC1 signaling activities. Conclusion These findings provide further data that contribute to understanding the possible relationships among mTOR activity, stress, and antidepressant drugs. Electronic supplementary material The online version of this article (doi:10.1186/s12868-017-0357-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Mi Kyoung Seo
- Paik Institute for Clinical Research, Inje University, 633-165 Gaegum-dong, Jin-gu, Busan, 614-735, Republic of Korea
| | - Cheol Min Choi
- Department of Health Science and Technology, Graduate School, Inje University, Busan, Republic of Korea
| | - Roger S McIntyre
- Mood Disorders Psychopharmacology Unit, University Health Network, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Hye Yeon Cho
- Paik Institute for Clinical Research, Inje University, 633-165 Gaegum-dong, Jin-gu, Busan, 614-735, Republic of Korea
| | - Chan Hong Lee
- Paik Institute for Clinical Research, Inje University, 633-165 Gaegum-dong, Jin-gu, Busan, 614-735, Republic of Korea
| | - Rodrigo B Mansur
- Mood Disorders Psychopharmacology Unit, University Health Network, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Yena Lee
- Mood Disorders Psychopharmacology Unit, University Health Network, Toronto, ON, Canada
| | - Jae-Hon Lee
- Department of Psychiatry, Korea University Ansan Hospital, Korea University College of Medicine, Ansan, Republic of Korea
| | - Young Hoon Kim
- Department of Psychiatry, Gongju National Hospital, Gongju, Republic of Korea
| | - Sung Woo Park
- Paik Institute for Clinical Research, Inje University, 633-165 Gaegum-dong, Jin-gu, Busan, 614-735, Republic of Korea. .,Department of Health Science and Technology, Graduate School, Inje University, Busan, Republic of Korea.
| | - Jung Goo Lee
- Paik Institute for Clinical Research, Inje University, 633-165 Gaegum-dong, Jin-gu, Busan, 614-735, Republic of Korea. .,Department of Health Science and Technology, Graduate School, Inje University, Busan, Republic of Korea. .,Mood Disorders Psychopharmacology Unit, University Health Network, Toronto, ON, Canada. .,Department of Psychiatry, School of Medicine, Haeundae Paik Hospital, Inje University, Busan, Republic of Korea.
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23
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Abstract
Eukaryotic translation initiation factor 4E (eIF4E)-binding protein 1 (4E-BP1) is a member of a family of translation repressor proteins, and a well-known substrate of mechanistic target of rapamycin (mTOR) signaling pathway. Phosphorylation of 4E-BP1 causes its release from eIF4E to allow cap-dependent translation to proceed. Recently, 4E-BP1 was shown to be phosphorylated by other kinases besides mTOR, and overexpression of 4E-BP1 was found in different human carcinomas. In this review, we summarize the novel findings on mTOR independent 4E-BP1 phosphorylation in carcinomas. The implications of overexpression and possible multi-function of 4E-BP1 are also discussed.
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Affiliation(s)
- Xiaoyu Qin
- a Department of Oncology , Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine , Shanghai , China
| | - Bin Jiang
- a Department of Oncology , Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine , Shanghai , China
| | - Yanjie Zhang
- a Department of Oncology , Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine , Shanghai , China
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24
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Mitotic protein kinase CDK1 phosphorylation of mRNA translation regulator 4E-BP1 Ser83 may contribute to cell transformation. Proc Natl Acad Sci U S A 2016; 113:8466-71. [PMID: 27402756 DOI: 10.1073/pnas.1607768113] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Mammalian target of rapamycin (mTOR)-directed eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) phosphorylation promotes cap-dependent translation and tumorigenesis. During mitosis, cyclin-dependent kinase 1 (CDK1) substitutes for mTOR and fully phosphorylates 4E-BP1 at canonical sites (T37, T46, S65, and T70) and the noncanonical S83 site, resulting in a mitosis-specific hyperphosphorylated δ isoform. Colocalization studies with a phospho-S83 specific antibody indicate that 4E-BP1 S83 phosphorylation accumulates at centrosomes during prophase, peaks at metaphase, and decreases through telophase. Although S83 phosphorylation of 4E-BP1 does not affect general cap-dependent translation, expression of an alanine substitution mutant 4E-BP1.S83A partially reverses rodent cell transformation induced by Merkel cell polyomavirus small T antigen viral oncoprotein. In contrast to inhibitory mTOR 4E-BP1 phosphorylation, these findings suggest that mitotic CDK1-directed phosphorylation of δ-4E-BP1 may yield a gain of function, distinct from translation regulation, that may be important in tumorigenesis and mitotic centrosome function.
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25
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An T, Li S, Pan W, Tien P, Zhong B, Shu HB, Wu S. DYRK2 Negatively Regulates Type I Interferon Induction by Promoting TBK1 Degradation via Ser527 Phosphorylation. PLoS Pathog 2015; 11:e1005179. [PMID: 26407194 PMCID: PMC4583546 DOI: 10.1371/journal.ppat.1005179] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 09/01/2015] [Indexed: 12/04/2022] Open
Abstract
Viral infection activates the transcription factors NF-κB and IRF3, which contribute to the induction of type I interferons (IFNs) and cellular antiviral responses. Protein kinases play a critical role in various signaling pathways by phosphorylating their substrates. Here, we identified dual-specificity tyrosine-(Y)-phosphorylation-regulated kinase 2 (DYRK2) as a negative regulator of virus-triggered type I IFN induction. DYRK2 inhibited the virus-triggered induction of type I IFNs and promoted the K48-linked ubiquitination and degradation of TANK-binding kinase 1 (TBK1) in a kinase-activity-dependent manner. We further found that DYRK2 phosphorylated Ser527 of TBK1, which is essential for the recruitment of NLRP4 and for the E3 ubiquitin ligase DTX4 to degrade TBK1. These findings suggest that DYRK2 negatively regulates virus-triggered signaling by targeting TBK1 for phosphorylation and priming it for degradation, and these data provide new insights into the molecular mechanisms that dictate the cellular antiviral response.
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Affiliation(s)
- Tai An
- The College of Life Sciences, State Key Laboratory of Virology, Modern Virology Research Center, Wuhan University, Wuhan, China
- The College of Basic Medical Science, Shaanxi University of Chinese Medicine, Xi’an, China
| | - Shu Li
- The College of Life Sciences, State Key Laboratory of Virology, Modern Virology Research Center, Wuhan University, Wuhan, China
| | - Wei Pan
- The College of Life Sciences, State Key Laboratory of Virology, Modern Virology Research Center, Wuhan University, Wuhan, China
| | - Po Tien
- The College of Life Sciences, State Key Laboratory of Virology, Modern Virology Research Center, Wuhan University, Wuhan, China
| | - Bo Zhong
- The College of Life Sciences, State Key Laboratory of Virology, Modern Virology Research Center, Wuhan University, Wuhan, China
| | - Hong-Bing Shu
- The College of Life Sciences, State Key Laboratory of Virology, Modern Virology Research Center, Wuhan University, Wuhan, China
| | - Shuwen Wu
- The College of Life Sciences, State Key Laboratory of Virology, Modern Virology Research Center, Wuhan University, Wuhan, China
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26
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Differential effects of antidepressant drugs on mTOR signalling in rat hippocampal neurons. Int J Neuropsychopharmacol 2014; 17:1831-46. [PMID: 24901414 DOI: 10.1017/s1461145714000534] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Recent studies suggest that ketamine produces antidepressant actions via stimulation of mammalian target of rapamycin (mTOR), leading to increased levels of synaptic proteins in the prefrontal cortex. Thus, mTOR activation may be related to antidepressant action. However, the mTOR signalling underlying antidepressant drug action has not been well investigated. The aim of the present study was to determine whether alterations in mTOR signalling were observed following treatment with antidepressant drugs, using ketamine as a positive control. Using Western blotting, we measured changes in the mTOR-mediated proteins and synaptic proteins in rat hippocampal cultures. Dendritic outgrowth was determined by neurite assay. Our findings demonstrated that escitalopram, paroxetine and tranylcypromine significantly increased levels of phospho-mTOR and its down-stream regulators (phospho-4E-BP-1 and phospho-p70S6K); fluoxetine, sertraline and imipramine had no effect. All drugs tested increased up-stream regulators (phospho-Akt and phospho-ERK) levels. Increased phospho-mTOR induced by escitalopram, paroxetine or tranylcypromine was significantly blocked in the presence of specific PI3K, MEK or mTOR inhibitors, respectively. All drugs tested also increased hippocampal dendritic outgrowth and synaptic proteins levels. The mTOR inhibitor, rapamycin, significantly blocked these effects on escitalopram, paroxetine and tranylcypromine whereas fluoxetine, sertraline and imipramine effects were not affected. The effects of escitalopram, paroxetine and tranylcypromine paralleled those of ketamine. This study presents novel in vitro evidence indicating that some antidepressant drugs promote dendritic outgrowth and increase synaptic protein levels through mTOR signalling; however, other antidepressant drugs seem to act via a different pathway. mTOR signalling may be a promising target for the development of new antidepressant drugs.
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27
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Grzmil M, Huber RM, Hess D, Frank S, Hynx D, Moncayo G, Klein D, Merlo A, Hemmings BA. MNK1 pathway activity maintains protein synthesis in rapalog-treated gliomas. J Clin Invest 2014; 124:742-54. [PMID: 24401275 DOI: 10.1172/jci70198] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Accepted: 10/30/2013] [Indexed: 01/20/2023] Open
Abstract
High levels of mammalian target of rapamycin complex 1 (mTORC1) activity in malignant gliomas promote tumor progression, suggesting that targeting mTORC1 has potential as a therapeutic strategy. Remarkably, clinical trials in patients with glioma revealed that rapamycin analogs (rapalogs) have limited efficacy, indicating activation of resistance mechanisms. Targeted depletion of MAPK-interacting Ser/Thr kinase 1 (MNK1) sensitizes glioma cells to the mTORC1 inhibitor rapamycin through an indistinct mechanism. Here, we analyzed how MNK1 and mTORC1 signaling pathways regulate the assembly of translation initiation complexes, using the cap analog m7GTP to enrich for initiation complexes in glioma cells followed by mass spectrometry-based quantitative proteomics. Association of eukaryotic translation initiation factor 4E (eIF4E) with eIF4E-binding protein 1 (4EBP1) was regulated by the mTORC1 pathway, whereas pharmacological blocking of MNK activity by CGP57380 or MNK1 knockdown, along with mTORC1 inhibition by RAD001, increased 4EBP1 binding to eIF4E. Furthermore, combined MNK1 and mTORC1 inhibition profoundly inhibited 4EBP1 phosphorylation at Ser65, protein synthesis and proliferation in glioma cells, and reduced tumor growth in an orthotopic glioblastoma (GBM) mouse model. Immunohistochemical analysis of GBM samples revealed increased 4EBP1 phosphorylation. Taken together, our data indicate that rapalog-activated MNK1 signaling promotes glioma growth through regulation of 4EBP1 and indicate a molecular cross-talk between the mTORC1 and MNK1 pathways that has potential to be exploited therapeutically.
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28
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Kim SH, Yu HS, Park HG, Ha K, Kim YS, Shin SY, Ahn YM. Intracerebroventricular administration of ouabain, a Na/K-ATPase inhibitor, activates mTOR signal pathways and protein translation in the rat frontal cortex. Prog Neuropsychopharmacol Biol Psychiatry 2013; 45:73-82. [PMID: 23643758 DOI: 10.1016/j.pnpbp.2013.04.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Revised: 04/02/2013] [Accepted: 04/21/2013] [Indexed: 11/16/2022]
Abstract
Intracerebroventricular (ICV) injection of ouabain, a specific Na/K-ATPase inhibitor, induces behavioral changes in rats in a putative animal model of mania. The binding of ouabain to Na/K-ATPase affects signaling molecules in vitro, including ERK1/2 and Akt, which promote protein translation. We have also reported that ERK1/2 and Akt in the brain are involved in the ouabain-induced hyperactivity of rats. In this study, rats were given an ICV injection of ouabain, and then their frontal cortices were examined to determine the effects of ouabain on the mTOR/p70S6K/S6 signaling pathway and protein translation, which are important in modifications of neural circuits and behavior. Rats showed ouabain-induced hyperactivity up to 8h following injection, and increased phosphorylation levels of mTOR, p70S6K, S6, eIF4B, and 4E-BP at 1, 2, 4, and 8h following ouabain injection. Immunohistochemical analyses revealed that increased p-S6 immunoreactivity in the cytoplasm of neurons by ouabain was evident in the prefrontal, cingulate, and orbital cortex. These findings suggested increased translation initiation in response to ouabain. The rate of protein synthesis was measured as the amount of [(3)H]-leucine incorporation in the cell-free extracts of frontal cortical tissues, and showed a significant increase at 8h after ouabain injection. These results suggest that ICV injection of ouabain induced activation of the protein translation initiation pathway regulated by ERK1/2 and Akt, and prolonged hyperactivity in rats. In conclusion, protein translation pathway could play an important role in ouabain-induced hyperactivity in a rodent model of mania.
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Affiliation(s)
- Se Hyun Kim
- Department of Psychiatry and Behavioral Science & Institute of Human Behavioral Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
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29
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Association of maternal mRNA and phosphorylated EIF4EBP1 variants with the spindle in mouse oocytes: localized translational control supporting female meiosis in mammals. Genetics 2013; 195:349-58. [PMID: 23852387 DOI: 10.1534/genetics.113.154005] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In contrast to other species, localized maternal mRNAs are not believed to be prominent features of mammalian oocytes. We find by cDNA microarray analysis enrichment for maternal mRNAs encoding spindle and other proteins on the mouse oocyte metaphase II (MII) spindle. We also find that the key translational regulator, EIF4EBP1, undergoes a dynamic and complex spatially regulated pattern of phosphorylation at sites that regulate its association with EIF4E and its ability to repress translation. These phosphorylation variants appear at different positions along the spindle at different stages of meiosis. These results indicate that dynamic spatially restricted patterns of EIF4EBP1 phosphorylation may promote localized mRNA translation to support spindle formation, maintenance, function, and other nearby processes. Regulated EIF4EBP1 phosphorylation at the spindle may help coordinate spindle formation with progression through the cell cycle. The discovery that EIF4EBP1 may be part of an overall mechanism that integrates and couples cell cycle progression to mRNA translation and subsequent spindle formation and function may be relevant to understanding mechanisms leading to diminished oocyte quality, and potential means of avoiding such defects. The localization of maternal mRNAs at the spindle is evolutionarily conserved between mammals and other vertebrates and is also seen in mitotic cells, indicating that EIF4EBP1 control of localized mRNA translation is likely key to correct segregation of genetic material across cell types.
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30
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Demeulder B, Zarrinpashneh E, Ginion A, Viollet B, Hue L, Rider MH, Vanoverschelde JL, Beauloye C, Horman S, Bertrand L. Differential regulation of eEF2 and p70S6K by AMPKalpha2 in heart. Biochim Biophys Acta Mol Basis Dis 2013; 1832:780-90. [DOI: 10.1016/j.bbadis.2013.02.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 02/17/2013] [Accepted: 02/25/2013] [Indexed: 01/13/2023]
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31
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Liu Y, Vertommen D, Rider MH, Lai YC. Mammalian target of rapamycin-independent S6K1 and 4E-BP1 phosphorylation during contraction in rat skeletal muscle. Cell Signal 2013; 25:1877-86. [PMID: 23707523 DOI: 10.1016/j.cellsig.2013.05.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 05/07/2013] [Indexed: 11/18/2022]
Abstract
Muscle protein synthesis rates decrease during contraction/exercise, but rapidly increase post-exercise. Previous studies mainly focused on signaling pathways that control protein synthesis during post-exercise recovery, such as mTOR and its downstream targets S6K1 and 4E-BP1. In this study, we investigated the effect of high-frequency electrical stimulation on the phosphorylation state of signaling components controlling protein synthesis in rat skeletal muscle. Electrical stimulation increased S6K1 Thr389 phosphorylation, which was unaffected by Torin1, a selective mTOR inhibitor, suggesting that S6K1 phosphorylation by contraction was mTOR-independent. Phosphorylation of eIF4B Ser422 was also increased during electrical stimulation, which was abrogated by inhibition of MEK/ERK/RSK1 activation. Moreover, although phosphorylation of conventional mTOR sites in 4E-BP1 decreased during contraction, mTOR-independent phosphorylation was also apparent, which was associated with the release of 4E-BP1 from eIF4E. The results indicate mTOR-independent phosphorylation of S6K1 and 4E-BP1 and suggest MEK/ERK/RSK1-dependent phosphorylation of eIF4B during skeletal muscle contraction. These phosphorylation events would keep the translation initiation machinery "primed" in an active state so that protein synthesis could quickly resume post-exercise.
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Affiliation(s)
- Yang Liu
- Université catholique de Louvain and de Duve Institute, Avenue Hippocrate 75, B-1200 Brussels, Belgium
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32
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Glycogen synthase kinase-3β positively regulates protein synthesis and cell proliferation through the regulation of translation initiation factor 4E-binding protein 1. Oncogene 2013; 33:1690-9. [DOI: 10.1038/onc.2013.113] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Revised: 12/31/2012] [Accepted: 02/15/2013] [Indexed: 12/17/2022]
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33
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Abstract
mRNA translation is the most energy consuming process in the cell. In addition, it plays a pivotal role in the control of gene expression and is therefore tightly regulated. In response to various extracellular stimuli and intracellular cues, signaling pathways induce quantitative and qualitative changes in mRNA translation by modulating the phosphorylation status and thus the activity of components of the translational machinery. In this work we focus on the phosphoinositide 3-kinase (PI3K)/AKT and the mitogen-activated protein kinase (MAPK) pathways, as they are strongly implicated in the regulation of translation in homeostasis, whereas their malfunction has been linked to aberrant translation in human diseases, including cancer.
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Affiliation(s)
- Philippe P Roux
- Institute for Research in Immunology and Cancer, Université de Montréal, Québec, Canada.
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Characterization of the neuropsychological phenotype of glycine N-methyltransferase-/- mice and evaluation of its responses to clozapine and sarcosine treatments. Eur Neuropsychopharmacol 2012; 22:596-606. [PMID: 22264868 DOI: 10.1016/j.euroneuro.2011.12.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 11/29/2011] [Accepted: 12/16/2011] [Indexed: 02/06/2023]
Abstract
Glycine N-methyltransferase (GNMT) affects cellular methylation capacity through regulating the ratio between S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH). The product of its enzymatic reaction-sarcosine has antipsychotic effect in patients with schizophrenia. In this study, through RT-PCR and immunohistochemical staining, we demonstrated that GNMT expressed in various neurons located in the cerebral cortex, hippocampus, substantia nigra and cerebellum. Compared to the wild-type mice, Gnmt-/- mice had significantly lower level of sarcosine in the cerebral cortex. Real-time PCR identified genes involved in the methionine metabolism (Dnmt1 and Dnmt3a), ErbB (Nrg1 and ErbB4) and mTOR (Akt2, S6, S6k1 and S6k2) signaling pathways were dysregulated significantly in the cortex of Gnmt-/- mice. Acoustic startle reflex test demonstrated that Gnmt-/- mice had significantly lower level of prepulse inhibition and the deficit was ameliorated through clozapine or sarcosine treatment. Furthermore, liver-specific-human-GNMT transgenic with Gnmt-/- (Tg-GNMT/Gnmt-/-) mice were used to rule out that the phenotype was due to abnormal liver function. In summary, the neuropsychological abnormalities found in Gnmt-/- mice may represent an endophenotype of schizophrenia. GNMT plays an important role in maintaining normal physiological function of brain and Tg-GNMT/Gnmt-/- mice are useful models for development of therapeutics for patients with schizophrenia.
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35
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Abstract
The recent development of mammalian target of rapamycin (mTOR) kinase domain inhibitors and genetic dissection of rapamycin-sensitive and -insensitive mTOR protein complexes (mTORC1 and mTORC2) have revealed that phosphorylation of the mTOR substrate 4E-BP1 on amino acids Thr37 and/or Thr46 represents a rapamycin-insensitive activity of mTORC1. Despite numerous previous reports utilizing serine (Ser)-to-alanine (Ala) and threonine (Thr)-to-Ala phosphorylation site mutants of 4E-BP1 to assess which post-translational modification(s) directly regulate binding to eIF4E, an ambiguous understanding persists. This manuscript demonstrates that the initial, rapamycin-insensitive phosphorylation event at Thr46 is sufficient to prevent eIF4E:4E-BP1 binding. This finding is relevant, particularly as mTOR kinase domain inhibitors continue to be assessed for clinical efficacy, since it clarifies a difference between the action of these second-generation mTOR inhibitors and those of rapamycin analogues.
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Affiliation(s)
- Mark Livingstone
- Biochemistry and McGill Cancer Centre, McGill University, Montreal, Canada ; Cytokine Signalling Unit, Institut Pasteur, Paris, France
| | - Michael Bidinosti
- Biochemistry and McGill Cancer Centre, McGill University, Montreal, Canada
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Martineau Y, Azar R, Bousquet C, Pyronnet S. Anti-oncogenic potential of the eIF4E-binding proteins. Oncogene 2012; 32:671-7. [DOI: 10.1038/onc.2012.116] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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37
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Ray RM, Viar MJ, Johnson LR. Amino acids regulate expression of antizyme-1 to modulate ornithine decarboxylase activity. J Biol Chem 2011; 287:3674-90. [PMID: 22157018 DOI: 10.1074/jbc.m111.232561] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
In a glucose-salt solution (Earle's balanced salt solution), asparagine (Asn) stimulates ornithine decarboxylase (ODC) activity in a dose-dependent manner, and the addition of epidermal growth factor (EGF) potentiates the effect of Asn. However, EGF alone fails to activate ODC. Thus, the mechanism by which Asn activates ODC is important for understanding the regulation of ODC activity. Asn reduced antizyme-1 (AZ1) mRNA and protein. Among the amino acids tested, Asn and glutamine (Gln) effectively inhibited AZ1 expression, suggesting a differential role for amino acids in the regulation of ODC activity. Asn decreased the putrescine-induced AZ1 translation. The absence of amino acids increased the binding of eukaryotic initiation factor 4E-binding protein (4EBP1) to 5'-mRNA cap and thereby inhibited global protein synthesis. Asn failed to prevent the binding of 4EBP1 to mRNA, and the bound 4EBP1 was unphosphorylated, suggesting the involvement of the mammalian target of rapamycin (mTOR) in the regulation of AZ1 synthesis. Rapamycin treatment (4 h) failed to alter the expression of AZ1. However, extending the treatment (24 h) allowed expression in the presence of amino acids, indicating that AZ1 is expressed when TORC1 signaling is decreased. This suggests the involvement of cap-independent translation. However, transient inhibition of mTORC2 by PP242 completely abolished the phosphorylation of 4EBP1 and decreased basal as well as putrescine-induced AZ1 expression. Asn decreased the phosphorylation of mTOR-Ser(2448) and AKT-Ser(473), suggesting the inhibition of mTORC2. In the absence of amino acids, mTORC1 is inhibited, whereas mTORC2 is activated, leading to the inhibition of global protein synthesis and increased AZ1 synthesis via a cap-independent mechanism.
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Affiliation(s)
- Ramesh M Ray
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA.
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Human cytomegalovirus infection maintains mTOR activity and its perinuclear localization during amino acid deprivation. J Virol 2011; 85:9369-76. [PMID: 21734039 DOI: 10.1128/jvi.05102-11] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The mammalian target of rapamycin (mTOR) kinase is present in 2 functionally distinct complexes, mTOR complex 1 (mTORC1) and complex 2 (mTORC2). Active mTORC1 mediates phosphorylation of eIF4E-binding protein (4E-BP) and p70 S6 kinase (S6K), which is important for maintaining translation. During human cytomegalovirus (HCMV) infection, cellular stress responses are activated that normally inhibit mTORC1; however, previous data show that HCMV infection circumvents stress responses and maintains mTOR kinase activity. Amino acid deprivation is a stress response that normally inhibits mTORC1 activity. Amino acids can signal to mTORC1 through the Rag proteins, which promote the colocalization of mTORC1 with its activator Rheb-GTP in a perinuclear region, thereby inducing 4E-BP and S6K phosphorylation. As expected, our results show that amino acid depletion in mock-infected cells caused loss of mTORC1 activity and loss of the perinuclear localization; however, there was no loss of activity or perinuclear localization in HCMV-infected cells where the perinuclear localization of Rheb-GTP and mTOR coincided with the perinuclear assembly compartment (AC). This suggested that HCMV infection bypasses normal Rag-dependent amino acid signaling. This was demonstrated by short hairpin RNA (shRNA) depletion of Rag proteins, which had little effect on mTORC1 activity in infected cells but inhibited activity in mock-infected cells. Our data show that HCMV maintains mTORC1 activity in an amino acid- and Rag-independent manner through the colocalization of mTOR and Rheb-GTP, which occurs in association with the formation of the AC, thus bypassing inhibition that may result from lowered amino acid levels.
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39
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Dobashi Y, Watanabe Y, Miwa C, Suzuki S, Koyama S. Mammalian target of rapamycin: a central node of complex signaling cascades. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2011; 4:476-495. [PMID: 21738819 PMCID: PMC3127069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Accepted: 06/13/2011] [Indexed: 05/31/2023]
Abstract
The mammalian target of rapamycin (mTOR) is a serine/threonine kinase that regulates cell growth and metabolism in response to diverse external stimuli. In the presence of mitogenic stimuli, mTOR transduces signals that activate the translational machinery and promote cell growth. mTOR functions as a central node in a complex net of signaling pathways that are involved both in normal physiological, as well as pathogenic events. mTOR signaling occurs in concert with upstream Akt and tuberous sclerosis complex (TSC) and several downstream effectors. During the past few decades, the mTOR-mediated pathway has been shown to promote tumorigenesis through the coordinated phosphorylation of proteins that directly regulate cell-cycle progression and metabolism, as well as transcription factors that regulate the expression of genes involved in the oncogenic processes. The importance of mTOR signaling in oncology is now widely accepted, and agents that selectively target mTOR have been developed as anti-cancer drugs. In this review, we highlight the past research on mTOR, including clinical and pathological analyses, and describe its molecular mechanisms of signaling, and its roles in the physiology and pathology of human diseases, particularly, lung carcinomas. We also discuss strategies that might lead to more effective clinical treatments of several diseases by targeting mTOR.
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Affiliation(s)
- Yoh Dobashi
- Department of Pathology, Respiratory Medicine Saitama, Japan.
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40
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Effects of neonatal MK-801 treatment on p70S6K-S6/eIF4B signal pathways and protein translation in the frontal cortex of the developing rat brain. Int J Neuropsychopharmacol 2010; 13:1233-46. [PMID: 20064280 DOI: 10.1017/s1461145709991192] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Systemic injections of MK-801, a selective NMDAR antagonist, into neonatal rats induces long-term neurochemical and behavioural changes. It has been suggested that these changes form the neurodevelopmental basis for schizophrenia-like behaviour in rats. In this study, 7-d-old rats were treated with MK-801, and their frontal cortices were examined to investigate the effects on p70S6K-S6 signal pathway and on protein translation, which play crucial roles in the neurodevelopmental process. MK-801, in doses of 0.5 and 1.0 mg/kg, induced a decrease in phosphorylation of p70S6K and its substrates, S6 and eIF4B, in the first 8 h, and no change at 24 and 48 h. These effects were more prominent after two injections of MK-801 than one. Decreased S6 phosphorylation by MK-801 was evident in the prefrontal, cingulate, and insular cortex. In two representative upstream p70S6K-S6 pathways related to ERK1/2 and Akt, changes in ERK1/2-p90RSK phosphorylation were accompanied by changes of p70S6K-S6. Although two MK-801 injections induced a dose-dependent decrease in phosphorylation of Akt and mTOR at 4 and 8 h, a single injection did not produce a significant effect. Protein synthesis rate, measured by [3H]leucine incorporation in frontal cortical tissue, was reduced until 24 h after two MK-801 (1.0 mg/kg) injections. In summary, this study found that neonatal MK-801 treatment induced dysregulation in the p70S6K-S6/eIF4B pathway and protein translation in the frontal cortex of the developing rat brain, which may suggest an important role of protein translation machinery in the MK-801 neurodevelopmental animal model of schizophrenia.
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41
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Local control of a disorder-order transition in 4E-BP1 underpins regulation of translation via eIF4E. Proc Natl Acad Sci U S A 2010; 107:17627-32. [PMID: 20880835 DOI: 10.1073/pnas.1008242107] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The molecular mechanism underpinning regulation of eukaryotic translation initiation factor eIF4E by 4E-BP1 has remained unclear. We use isothermal calorimetry, circular dichroism, NMR, and computational modeling to analyze how the structure of the eIF4E-binding domain of 4E-BP1 determines its affinity for the dorsal face of eIF4E and thus the ability of this regulator to act as a competitive inhibitor. This work identifies the key role of solvent-facing amino acids in 4E-BP1 that are not directly engaged in interactions with eIF4E. These amino acid residues influence the propensity of the natively unfolded binding motif to fold into a conformation, including a stretch of α-helix, that is required for tight binding to eIF4E. In so doing, they contribute to a free energy landscape for 4E-BP1 folding that is poised so that phosphorylation of S65 at the C-terminal end of the helical region can modulate the propensity of folding, and thus regulate the overall free energy of 4E-BP1 binding to eIF4E, over a physiologically significant range. Thus, phosphorylation acts as an intramolecular structural modulator that biases the free energy landscape for the disorder-order transition of 4E-BP1 by destabilizing the α-helix to favor the unfolded form that cannot bind eIF4E. This type of order-disorder regulatory mechanism is likely to be relevant to other intermolecular regulatory phenomena in the cell.
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42
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Ayuso MI, Hernández-Jiménez M, Martín ME, Salinas M, Alcázar A. New hierarchical phosphorylation pathway of the translational repressor eIF4E-binding protein 1 (4E-BP1) in ischemia-reperfusion stress. J Biol Chem 2010; 285:34355-63. [PMID: 20736160 PMCID: PMC2966049 DOI: 10.1074/jbc.m110.135103] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Eukaryotic initiation factor (eIF) 4E-binding protein 1 (4E-BP1) is a translational repressor that is characterized by its capacity to bind specifically to eIF4E and inhibit its interaction with eIF4G. Phosphorylation of 4E-BP1 regulates eIF4E availability, and therefore, cap-dependent translation, in cell stress. This study reports a physiological study of 4E-BP1 regulation by phosphorylation using control conditions and a stress-induced translational repression condition, ischemia-reperfusion (IR) stress, in brain tissue. In control conditions, 4E-BP1 was found in four phosphorylation states that were detected by two-dimensional gel electrophoresis and Western blotting, which corresponded to Thr69-phosphorylated alone, Thr69- and Thr36/Thr45-phosphorylated, all these plus Ser64 phosphorylation, and dephosphorylation of the sites analyzed. In control or IR conditions, no Thr36/Thr45 phosphorylation alone was detected without Thr69 phosphorylation, and neither was Ser64 phosphorylation without Thr36/Thr45/Thr69 phosphorylation detected. Ischemic stress induced 4E-BP1 dephosphorylation at Thr69, Thr36/Thr45, and Ser64 residues, with 4E-BP1 remaining phosphorylated at Thr69 alone or dephosphorylated. In the subsequent reperfusion, 4E-BP1 phosphorylation was induced at Thr36/Thr45 and Ser64, in addition to Thr69. Changes in 4E-BP1 phosphorylation after IR were according to those found for Akt and mammalian target of rapamycin (mTOR) kinases. These results demonstrate a new hierarchical phosphorylation for 4E-BP1 regulation in which Thr69 is phosphorylated first followed by Thr36/Thr45 phosphorylation, and Ser64 is phosphorylated last. Thr69 phosphorylation alone allows binding to eIF4E, and subsequent Thr36/Thr45 phosphorylation was sufficient to dissociate 4E-BP1 from eIF4E, which led to eIF4E-4G interaction. These data help to elucidate the physiological role of 4E-BP1 phosphorylation in controlling protein synthesis.
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Affiliation(s)
- María I Ayuso
- Department of Investigation, Hospital Ramón y Cajal, 28034 Madrid, Spain
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43
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Bidinosti M, Ran I, Sanchez-Carbente MR, Martineau Y, Gingras AC, Gkogkas C, Raught B, Bramham CR, Sossin WS, Costa-Mattioli M, DesGroseillers L, Lacaille JC, Sonenberg N. Postnatal deamidation of 4E-BP2 in brain enhances its association with raptor and alters kinetics of excitatory synaptic transmission. Mol Cell 2010; 37:797-808. [PMID: 20347422 DOI: 10.1016/j.molcel.2010.02.022] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2009] [Revised: 12/06/2009] [Accepted: 02/21/2010] [Indexed: 10/19/2022]
Abstract
The eIF4E-binding proteins (4E-BPs) repress translation initiation by preventing eIF4F complex formation. Of the three mammalian 4E-BPs, only 4E-BP2 is enriched in the mammalian brain and plays an important role in synaptic plasticity and learning and memory formation. Here we describe asparagine deamidation as a brain-specific posttranslational modification of 4E-BP2. Deamidation is the spontaneous conversion of asparagines to aspartates. Two deamidation sites were mapped to an asparagine-rich sequence unique to 4E-BP2. Deamidated 4E-BP2 exhibits increased binding to the mammalian target of rapamycin (mTOR)-binding protein raptor, which effects its reduced association with eIF4E. 4E-BP2 deamidation occurs during postnatal development, concomitant with the attenuation of the activity of the PI3K-Akt-mTOR signaling pathway. Expression of deamidated 4E-BP2 in 4E-BP2(-/-) neurons yielded mEPSCs exhibiting increased charge transfer with slower rise and decay kinetics relative to the wild-type form. 4E-BP2 deamidation may represent a compensatory mechanism for the developmental reduction of PI3K-Akt-mTOR signaling.
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Affiliation(s)
- Michael Bidinosti
- Department of Biochemistry and Goodman Cancer Centre, McGill University, Montréal, QC H3G 1Y6, Canada
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44
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Westmark PR, Westmark CJ, Wang S, Levenson J, O'Riordan KJ, Burger C, Malter JS. Pin1 and PKMzeta sequentially control dendritic protein synthesis. Sci Signal 2010; 3:ra18. [PMID: 20215645 DOI: 10.1126/scisignal.2000451] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Some forms of learning and memory and their electrophysiologic correlate, long-term potentiation (LTP), require dendritic translation. We demonstrate that Pin1 (protein interacting with NIMA 1), a peptidyl-prolyl isomerase, is present in dendritic spines and shafts and inhibits protein synthesis induced by glutamatergic signaling. Pin1 suppression increased dendritic translation, possibly through eukaryotic translation initiation factor 4E (eIF4E) and eIF4E binding proteins 1 and 2 (4E-BP1/2). Consistent with increased protein synthesis, hippocampal slices from Pin(-/-) mice had normal early LTP (E-LTP) but significantly enhanced late LTP (L-LTP) compared to wild-type controls. Protein kinase C zeta (PKCzeta) and protein kinase M zeta (PKMzeta) were increased in Pin1(-/-) mouse brain, and their activity was required to maintain dendritic translation. PKMzeta interacted with and inhibited Pin1 by phosphorylating serine 16. Therefore, glutamate-induced, dendritic protein synthesis is sequentially regulated by Pin1 and PKMzeta signaling.
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Affiliation(s)
- Pamela R Westmark
- Department of Pathology and Laboratory Medicine and Waisman Center for Developmental Disabilities, University of Wisconsin, Madison, WI 53705, USA
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45
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Mahoney SJ, Dempsey JM, Blenis J. Cell signaling in protein synthesis ribosome biogenesis and translation initiation and elongation. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2009; 90:53-107. [PMID: 20374739 DOI: 10.1016/s1877-1173(09)90002-3] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Protein synthesis is a highly energy-consuming process that must be tightly regulated. Signal transduction cascades respond to extracellular and intracellular cues to phosphorylate proteins involved in ribosomal biogenesis and translation initiation and elongation. These phosphorylation events regulate the timing and rate of translation of both specific and total mRNAs. Alterations in this regulation can result in dysfunction and disease. While many signaling pathways intersect to control protein synthesis, the mTOR and MAPK pathways appear to be key players. This chapter briefly reviews the mTOR and MAPK pathways and then focuses on individual phosphorylation events that directly control ribosome biogenesis and translation.
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Affiliation(s)
- Sarah J Mahoney
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
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46
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Kasinath BS, Feliers D, Sataranatarajan K, Ghosh Choudhury G, Lee MJ, Mariappan MM. Regulation of mRNA translation in renal physiology and disease. Am J Physiol Renal Physiol 2009; 297:F1153-65. [PMID: 19535566 DOI: 10.1152/ajprenal.90748.2008] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Translation, a process of generating a peptide from the codons present in messenger RNA, can be a site of independent regulation of protein synthesis; it has not been well studied in the kidney. Translation occurs in three stages (initiation, elongation, and termination), each with its own set of regulatory factors. Mechanisms controlling translation include small inhibitory RNAs such as microRNAs, binding proteins, and signaling reactions. Role of translation in renal injury in diabetes, endoplasmic reticulum stress, acute kidney injury, and, in physiological adaptation to loss of nephrons is reviewed here. Contribution of mRNA translation to physiology and disease is not well understood. Because it is involved in such diverse areas as development and cancer, it should prove a fertile field for investigation in renal science.
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Affiliation(s)
- Balakuntalam S Kasinath
- Division of Nephrology, Department of Medicine, University of Texas Health Science Center, San Antonio, TX 78229-3900, USA.
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47
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Optical reporters for the conformation of alpha-synuclein reveal a specific interaction with mitochondria. J Neurosci 2009; 28:12305-17. [PMID: 19020024 DOI: 10.1523/jneurosci.3088-08.2008] [Citation(s) in RCA: 158] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The aggregation of abnormally folded proteins is a defining feature of neurodegenerative disease, but it has not previously been possible to assess the conformation of these proteins in a physiologically relevant context, before they form morphologically recognizable aggregates. We now describe FRET-based reporters for the conformation of alpha-synuclein, a protein central to the pathogenesis of Parkinson's disease (PD). Characterization in vitro shows that alpha-synuclein adopts a relatively "closed" conformation in solution that converts to "open" on membrane binding. In living cells, the closed conformation predominates. In neurons, however, cell bodies contain a much larger proportion of the open conformation than synaptic boutons. To account for these differences, we also used the reporters to characterize the interaction with native membranes. We find that the conformation of alpha-synuclein responds selectively to mitochondria, indicating a direct link between alpha-synuclein and an organelle strongly implicated in the pathogenesis of PD.
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48
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Willett M, Cowan JL, Vlasak M, Coldwell MJ, Morley SJ. Inhibition of mammalian target of rapamycin (mTOR) signalling in C2C12 myoblasts prevents myogenic differentiation without affecting the hyperphosphorylation of 4E-BP1. Cell Signal 2009; 21:1504-12. [PMID: 19481146 DOI: 10.1016/j.cellsig.2009.05.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 05/18/2009] [Accepted: 05/20/2009] [Indexed: 10/20/2022]
Abstract
Current accepted models suggest that hypophosphorylated 4E-binding protein (4E-BP1) binds to initiation factor 4E (eIF4E) to inhibit cap-dependent translation, a process readily reversed by its phosphorylation following activation of mammalian target of rapamycin (mTORC1) signalling. Myogenic differentiation in the C2C12 myoblast model system reflects a concerted and controlled activation of transcription and translation following the exit of cells from the cell cycle. Here we show that myogenic differentiation is associated with increased rates of translation, the up-regulation of both 4E-BP1 mRNA and protein levels and enhanced levels of eIF4E/4E-BP1 complex. Paradoxically, treatment of C2C12 myoblasts with an inhibitor of mTOR signalling (RAD001) which inhibits translation, promotes the hyperphosphorylation of 4E-BP1 on novel sites and prevents the increase in 4E-BP1 levels. In contrast, eIF4E appears to be under translational control with a significant delay between induction of mRNA and subsequent protein expression.
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Affiliation(s)
- Mark Willett
- Department of Biochemistry, School of Life Sciences, University of Sussex, Falmer, Brighton BN19QG, UK
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49
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Oulhen N, Boulben S, Bidinosti M, Morales J, Cormier P, Cosson B. A variant mimicking hyperphosphorylated 4E-BP inhibits protein synthesis in a sea urchin cell-free, cap-dependent translation system. PLoS One 2009; 4:e5070. [PMID: 19333389 PMCID: PMC2659438 DOI: 10.1371/journal.pone.0005070] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2008] [Accepted: 03/03/2009] [Indexed: 12/03/2022] Open
Abstract
Background 4E-BP is a translational inhibitor that binds to eIF4E to repress cap-dependent translation initiation. This critical protein:protein interaction is regulated by the phosphorylation of 4E-BP. Hypophosphorylated 4E-BP binds to eIF4E and inhibits cap-dependent translation, whereas hyperphosphorylated forms do not. While three 4E-BP proteins exist in mammals, only one gene encoding for 4E-BP is present in the sea urchin genome. The protein product has a highly conserved core domain containing the eIF4E-binding domain motif (YxxxxLΦ) and four of the regulatory phosphorylation sites. Methodology/Principal Findings Using a sea urchin cell-free cap-dependent translation system prepared from fertilized eggs, we provide the first direct evidence that the sea urchin 4E-BP inhibits cap-dependent translation. We show here that a sea urchin 4E-BP variant, mimicking phosphorylation on four core residues required to abrogate binding to eIF4E, surprisingly maintains physical association to eIF4E and inhibits protein synthesis. Conclusions/Significance Here, we examine the involvement of the evolutionarily conserved core domain and phosphorylation sites of sea urchin 4E-BP in the regulation of eIF4E-binding. These studies primarily demonstrate the conserved activity of the 4E-BP translational repressor and the importance of the eIF4E-binding domain in sea urchin. We also show that a variant mimicking hyperphosphorylation of the four regulatory phosphorylation sites common to sea urchin and human 4E-BP is not sufficient for release from eIF4E and translation promotion. Therefore, our results suggest that there are additional mechanisms to that of phosphorylation at the four critical sites of 4E-BP that are required to disrupt binding to eIF4E.
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Affiliation(s)
- Nathalie Oulhen
- UPMC Univ Paris 06, UMR 7150, Equipe Traduction Cycle Cellulaire et Développement, Station Biologique de Roscoff, Roscoff, France
- CNRS, UMR 7150, Station Biologique de Roscoff, Roscoff, France
- Université Européenne de Bretagne, Bretagne, France
| | - Sandrine Boulben
- UPMC Univ Paris 06, UMR 7150, Equipe Traduction Cycle Cellulaire et Développement, Station Biologique de Roscoff, Roscoff, France
- CNRS, UMR 7150, Station Biologique de Roscoff, Roscoff, France
- Université Européenne de Bretagne, Bretagne, France
| | - Michael Bidinosti
- Department of Biochemistry and Rosalind and Morris Goodman Cancer Centre, McGill University, Montreal, Quebec, Canada
| | - Julia Morales
- UPMC Univ Paris 06, UMR 7150, Equipe Traduction Cycle Cellulaire et Développement, Station Biologique de Roscoff, Roscoff, France
- CNRS, UMR 7150, Station Biologique de Roscoff, Roscoff, France
- Université Européenne de Bretagne, Bretagne, France
| | - Patrick Cormier
- UPMC Univ Paris 06, UMR 7150, Equipe Traduction Cycle Cellulaire et Développement, Station Biologique de Roscoff, Roscoff, France
- CNRS, UMR 7150, Station Biologique de Roscoff, Roscoff, France
- Université Européenne de Bretagne, Bretagne, France
| | - Bertrand Cosson
- UPMC Univ Paris 06, UMR 7150, Equipe Traduction Cycle Cellulaire et Développement, Station Biologique de Roscoff, Roscoff, France
- CNRS, UMR 7150, Station Biologique de Roscoff, Roscoff, France
- Université Européenne de Bretagne, Bretagne, France
- * E-mail:
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Amornphimoltham P, Leelahavanichkul K, Molinolo A, Patel V, Gutkind JS. Inhibition of Mammalian target of rapamycin by rapamycin causes the regression of carcinogen-induced skin tumor lesions. Clin Cancer Res 2008; 14:8094-101. [PMID: 19073969 DOI: 10.1158/1078-0432.ccr-08-0703] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
PURPOSE The activation of Akt/mammalian target of rapamycin (mTOR) pathway represents a frequent event in squamous cell carcinoma (SCC) progression, thus raising the possibility of using specific mTOR inhibitors for the treatment of SCC patients. In this regard, blockade of mTOR with rapamycin prevents the growth of human head and neck SCC cells when xenotransplanted into immunodeficient mice. However, therapeutic responses in xenograft tumors are not always predictive of clinical anticancer activity. EXPERIMENTAL DESIGN As genetically defined and chemically induced animal cancer models often reflect better the complexity of the clinical setting, we used here a two-step chemical carcinogenesis model to explore the effectiveness of rapamycin for the treatment of skin SCC. RESULTS Rapamycin exerted a remarkable anticancer activity in this chemically induced cancer model, decreasing the tumor burden of mice harboring early and advanced tumor lesions, and even recurrent skin SCCs. Immunohistochemical studies on tumor biopsies and clustering analysis revealed that rapamycin causes the rapid decrease in the phosphorylation status of mTOR targets followed by the apoptotic death of cancer cells and the reduction in the growth and metabolic activity of the surviving ones, concomitant with a decrease in the population of cancer cells expressing mutant p53. This approach enabled investigating the relationship among molecular changes caused by mTOR inhibition, thus helping identify relevant biomarkers for monitoring the effectiveness of mTOR inhibition in the clinical setting. CONCLUSIONS Together, these findings provide a strong rationale for the early evaluation of mTOR inhibitors as a molecular targeted approach to treat SCC.
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Affiliation(s)
- Panomwat Amornphimoltham
- Oral and Pharyngeal Cancer Branch, National Institute of Craniofacial and Dental Research, NIH, Bethesda, Maryland 20892-4330, USA
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