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Backlund AE, Bain B, Kite K, Babbitt C, Long LJ, Leatherman J, Schwartz B, Rele CP, Reed LK. Gene model for the ortholog of rictor in Drosophila ananassae. MICROPUBLICATION BIOLOGY 2025; 2025:10.17912/micropub.biology.000982. [PMID: 40321833 PMCID: PMC12046423 DOI: 10.17912/micropub.biology.000982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 04/16/2025] [Accepted: 04/01/2025] [Indexed: 05/08/2025]
Abstract
Gene model for the ortholog of rapamycin-insensitive companion of Tor ( rictor ) in the May 2011 (Agencourt dana_caf1/DanaCAF1) Genome Assembly (GenBank Accession: GCA_000005115.1 ) of Drosophila ananassae . This ortholog was characterized as part of a developing dataset to study the evolution of the Insulin/insulin-like growth factor signaling pathway (IIS) across the genus Drosophila using the Genomics Education Partnership gene annotation protocol for Course-based Undergraduate Research Experiences.
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Affiliation(s)
| | | | - Kayton Kite
- Oklahoma Christian University, Edmond, OK USA
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2
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Frappaolo A, Zaccagnini G, Giansanti MG. GOLPH3-mTOR Crosstalk and Glycosylation: A Molecular Driver of Cancer Progression. Cells 2025; 14:439. [PMID: 40136688 PMCID: PMC11941073 DOI: 10.3390/cells14060439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2025] [Revised: 03/06/2025] [Accepted: 03/13/2025] [Indexed: 03/27/2025] Open
Abstract
Originally identified in proteomic-based studies of the Golgi, Golgi phosphoprotein 3 (GOLPH3) is a highly conserved protein from yeast to humans. GOLPH3 localizes to the Golgi through the interaction with phosphatidylinositol-4-phosphate and is required for Golgi architecture and vesicular trafficking. Many studies revealed that the overexpression of GOLPH3 is associated with tumor metastasis and a poor prognosis in several cancer types, including breast cancer, glioblastoma multiforme, and colon cancer. The purpose of this review article is to provide the current progress of our understanding of GOLPH3 molecular and cellular functions, which may potentially reveal therapeutic avenues to inhibit its activity. Specifically, recent papers have demonstrated that GOLPH3 protein functions as a cargo adaptor for COP I-coated intra Golgi vesicles and impinges on Golgi glycosylation pathways. In turn, GOLPH3-dependent defects have been associated with malignant phenotypes in cancer cells. Additionally, the oncogenic activity of GOLPH3 has been linked with enhanced signaling downstream of mechanistic target of rapamycin (mTOR) in several cancer types. Consistent with these data, GOLPH3 controls organ growth in Drosophila by associating with mTOR signaling proteins. Finally, compelling evidence demonstrates that GOLPH3 is essential for cytokinesis, a process required for the maintenance of genomic stability.
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Affiliation(s)
| | | | - Maria Grazia Giansanti
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, 00185 Roma, Italy; (A.F.); (G.Z.)
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3
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Frappaolo A, Giansanti MG. Using Drosophila melanogaster to Dissect the Roles of the mTOR Signaling Pathway in Cell Growth. Cells 2023; 12:2622. [PMID: 37998357 PMCID: PMC10670727 DOI: 10.3390/cells12222622] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 11/10/2023] [Accepted: 11/11/2023] [Indexed: 11/25/2023] Open
Abstract
The evolutionarily conserved target of rapamycin (TOR) serine/threonine kinase controls eukaryotic cell growth, metabolism and survival by integrating signals from the nutritional status and growth factors. TOR is the catalytic subunit of two distinct functional multiprotein complexes termed mTORC1 (mechanistic target of rapamycin complex 1) and mTORC2, which phosphorylate a different set of substrates and display different physiological functions. Dysregulation of TOR signaling has been involved in the development and progression of several disease states including cancer and diabetes. Here, we highlight how genetic and biochemical studies in the model system Drosophila melanogaster have been crucial to identify the mTORC1 and mTORC2 signaling components and to dissect their function in cellular growth, in strict coordination with insulin signaling. In addition, we review new findings that involve Drosophila Golgi phosphoprotein 3 in regulating organ growth via Rheb-mediated activation of mTORC1 in line with an emerging role for the Golgi as a major hub for mTORC1 signaling.
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Affiliation(s)
- Anna Frappaolo
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, 00185 Roma, Italy
| | - Maria Grazia Giansanti
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, 00185 Roma, Italy
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4
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Fu Y, Fu Z, Su Z, Li L, Yang Y, Tan Y, Xiang Y, Shi Y, Xie S, Sun L, Peng G. mLST8 is essential for coronavirus replication and regulates its replication through the mTORC1 pathway. mBio 2023; 14:e0089923. [PMID: 37377422 PMCID: PMC10470783 DOI: 10.1128/mbio.00899-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 05/11/2023] [Indexed: 06/29/2023] Open
Abstract
Coronaviruses (CoVs), which pose a serious threat to human and animal health worldwide, need to hijack host factors to complete their replicative cycles. However, the current study of host factors involved in CoV replication remains unknown. Here, we identified a novel host factor, mammalian lethal with sec-13 protein 8 (mLST8), which is a common subunit of mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2), and is critical for CoV replication. Inhibitor and knockout (KO) experiments revealed that mTORC1, but not mTORC2, is essential for transmissible gastroenteritis virus replication. Furthermore, mLST8 KO reduced the phosphorylation of unc-51-like kinase 1 (ULK1), a factor downstream of the mTORC1 signaling pathway, and mechanistic studies revealed that decreased phosphorylation of the mTORC1 downstream factor ULK1 promoted the activation of autophagy, which is responsible for antiviral replication in mLST8 KO cells. Then, transmission electron microscopy indicated that both mLST8 KO and autophagy activator inhibited the formation of double-membrane vesicles in early viral replication. Finally, mLST8 KO and autophagy activator treatment could also inhibit the replication of other CoVs, indicating a conserved relationship between autophagy activation and CoV replication. In summary, our work reveals that mLST8 is a novel host regulator of CoV replication, which provides new insights into the mechanism of CoV replication and can facilitate the development of broad-spectrum antiviral drugs. IMPORTANCE CoVs are highly variable, and existing CoV vaccines are still limited in their ability to address mutations in CoVs. Therefore, the need to improve our understanding of the interaction of CoVs with the host during viral replication and to find targets for drugs against CoVs is urgent. Here, we found that a novel host factor, mLST8, is critical for CoV infection. Further studies showed that mLST8 KO inhibited the mTORC1 signaling pathway, and we found that autophagy activation downstream of mTORC1 was the main cause of antiviral replication in mLST8 KO cells. Autophagy activation impaired the formation of DMVs and inhibited early viral replication. These findings deepen our understanding of the CoV replication process and provide insights into potential therapeutic applications.
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Affiliation(s)
- Yanan Fu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| | - Zhen Fu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| | - Zhelin Su
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| | - Lisha Li
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| | - Yilin Yang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| | - Yubei Tan
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| | - Yixin Xiang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| | - Yuejun Shi
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| | - Shengsong Xie
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education & Key Lab of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China
| | - Limeng Sun
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| | - Guiqing Peng
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
- Key Laboratory of Prevention & Control for African Swine Fever and Other Major Pig Diseases, Ministry of Agriculture and Rural Affairs, Wuhan, China
- Hubei Hongshan Laboratory, Frontiers Science Center for Animal Breeding and Sustainable Production, Wuhan, China
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Frappaolo A, Karimpour-Ghahnavieh A, Cesare G, Sechi S, Fraschini R, Vaccari T, Giansanti MG. GOLPH3 protein controls organ growth by interacting with TOR signaling proteins in Drosophila. Cell Death Dis 2022; 13:1003. [PMID: 36435842 PMCID: PMC9701223 DOI: 10.1038/s41419-022-05438-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 11/11/2022] [Accepted: 11/14/2022] [Indexed: 11/28/2022]
Abstract
The oncoprotein GOLPH3 (Golgi phosphoprotein 3) is an evolutionarily conserved phosphatidylinositol 4-phosphate effector, mainly localized to the Golgi apparatus, where it supports organelle architecture and vesicular trafficking. Overexpression of human GOLPH3 correlates with poor prognosis in several cancer types and is associated with enhanced signaling downstream of mTOR (mechanistic target of rapamycin). However, the molecular link between GOLPH3 and mTOR remains elusive. Studies in Drosophila melanogaster have shown that Translationally controlled tumor protein (Tctp) and 14-3-3 proteins are required for organ growth by supporting the function of the small GTPase Ras homolog enriched in the brain (Rheb) during mTORC1 (mTOR complex 1) signaling. Here we demonstrate that Drosophila GOLPH3 (dGOLPH3) physically interacts with Tctp and 14-3-3ζ. RNAi-mediated knockdown of dGOLPH3 reduces wing and eye size and enhances the phenotypes of Tctp RNAi. This phenotype is partially rescued by overexpression of Tctp, 14-3-3ζ, or Rheb. We also show that the Golgi localization of Rheb in Drosophila cells depends on dGOLPH3. Consistent with dGOLPH3 involvement in Rheb-mediated mTORC1 activation, depletion of dGOLPH3 also reduces levels of phosphorylated ribosomal S6 kinase, a downstream target of mTORC1. Finally, the autophagy flux and the expression of autophagic transcription factors of the TFEB family, which anti correlates with mTOR signaling, are compromised upon reduction of dGOLPH3. Overall, our data provide the first in vivo demonstration that GOLPH3 regulates organ growth by directly associating with mTOR signaling proteins.
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Affiliation(s)
- Anna Frappaolo
- grid.7841.aIstituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, 00185 Roma, Italy
| | - Angela Karimpour-Ghahnavieh
- grid.7841.aIstituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, 00185 Roma, Italy
| | - Giuliana Cesare
- grid.4708.b0000 0004 1757 2822Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, Italy
| | - Stefano Sechi
- grid.7841.aIstituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, 00185 Roma, Italy
| | - Roberta Fraschini
- grid.7563.70000 0001 2174 1754Dipartimento di Biotecnologie e Bioscienze, Università degli studi di Milano Bicocca, 20126 Milano, Italy
| | - Thomas Vaccari
- grid.4708.b0000 0004 1757 2822Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, Italy
| | - Maria Grazia Giansanti
- grid.7841.aIstituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, 00185 Roma, Italy
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6
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Ogienko AA, Omelina ES, Bylino OV, Batin MA, Georgiev PG, Pindyurin AV. Drosophila as a Model Organism to Study Basic Mechanisms of Longevity. Int J Mol Sci 2022; 23:11244. [PMID: 36232546 PMCID: PMC9569508 DOI: 10.3390/ijms231911244] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 09/20/2022] [Accepted: 09/20/2022] [Indexed: 11/16/2022] Open
Abstract
The spatio-temporal regulation of gene expression determines the fate and function of various cells and tissues and, as a consequence, the correct development and functioning of complex organisms. Certain mechanisms of gene activity regulation provide adequate cell responses to changes in environmental factors. Aside from gene expression disorders that lead to various pathologies, alterations of expression of particular genes were shown to significantly decrease or increase the lifespan in a wide range of organisms from yeast to human. Drosophila fruit fly is an ideal model system to explore mechanisms of longevity and aging due to low cost, easy handling and maintenance, large number of progeny per adult, short life cycle and lifespan, relatively low number of paralogous genes, high evolutionary conservation of epigenetic mechanisms and signalling pathways, and availability of a wide range of tools to modulate gene expression in vivo. Here, we focus on the organization of the evolutionarily conserved signaling pathways whose components significantly influence the aging process and on the interconnections of these pathways with gene expression regulation.
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Affiliation(s)
- Anna A. Ogienko
- Department of Regulation of Genetic Processes, Institute of Molecular and Cellular Biology SB RAS, 630090 Novosibirsk, Russia
| | - Evgeniya S. Omelina
- Department of Regulation of Genetic Processes, Institute of Molecular and Cellular Biology SB RAS, 630090 Novosibirsk, Russia
- Laboratory of Biotechnology, Novosibirsk State Agrarian University, 630039 Novosibirsk, Russia
| | - Oleg V. Bylino
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology RAS, 119334 Moscow, Russia
| | - Mikhail A. Batin
- Open Longevity, 15260 Ventura Blvd., Sherman Oaks, Los Angeles, CA 91403, USA
| | - Pavel G. Georgiev
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology RAS, 119334 Moscow, Russia
| | - Alexey V. Pindyurin
- Department of Regulation of Genetic Processes, Institute of Molecular and Cellular Biology SB RAS, 630090 Novosibirsk, Russia
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7
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Luciano AK, Korobkina E, Lyons SP, Haley JA, Fluharty S, Jung SM, Kettenbach AN, Guertin DA. Proximity labeling of endogenous RICTOR identifies mTOR Complex 2 regulation by ADP ribosylation factor ARF1. J Biol Chem 2022; 298:102379. [PMID: 35973513 PMCID: PMC9513271 DOI: 10.1016/j.jbc.2022.102379] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 07/22/2022] [Accepted: 08/09/2022] [Indexed: 01/08/2023] Open
Abstract
Mechanistic target of rapamycin (mTOR) complex 2 (mTORC2) regulates metabolism, cell proliferation, and cell survival. mTORC2 activity is stimulated by growth factors, and it phosphorylates the hydrophobic motif site of the AGC kinases AKT, SGK, and PKC. However, the proteins that interact with mTORC2 to control its activity and localization remain poorly defined. To identify mTORC2-interacting proteins in living cells, we tagged endogenous RICTOR, an essential mTORC2 subunit, with the modified BirA biotin ligase BioID2 and performed live-cell proximity labeling. We identified 215 RICTOR-proximal proteins, including proteins with known mTORC2 pathway interactions, and 135 proteins (63%) not previously linked to mTORC2 signaling, including nuclear and cytoplasmic proteins. Our imaging and cell fractionation experiments suggest nearly 30% of RICTOR is in the nucleus, hinting at potential nuclear functions. We also identified 29 interactors containing RICTOR-dependent, insulin-stimulated phosphorylation sites, thus providing insight into mTORC2-dependent insulin signaling dynamics. Finally, we identify the endogenous ADP ribosylation factor 1 (ARF1) GTPase as an mTORC2-interacting protein. Through gain-of-function and loss-of-function studies, we provide functional evidence that ARF1 may negatively regulate mTORC2. In summary, we present a new method of studying endogenous mTORC2, a resource of RICTOR/mTORC2 protein interactions in living cells, and a potential mechanism of mTORC2 regulation by the ARF1 GTPase.
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Affiliation(s)
- Amelia K Luciano
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA 01605
| | - Ekaterina Korobkina
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA 01605
| | - Scott P Lyons
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - John A Haley
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA 01605
| | - Shelagh Fluharty
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA 01605
| | - Su Myung Jung
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA 01605
| | - Arminja N Kettenbach
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755; Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - David A Guertin
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA 01605; Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605.
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8
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Villa-González M, Martín-López G, Pérez-Álvarez MJ. Dysregulation of mTOR Signaling after Brain Ischemia. Int J Mol Sci 2022; 23:ijms23052814. [PMID: 35269956 PMCID: PMC8911477 DOI: 10.3390/ijms23052814] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/28/2022] [Accepted: 03/01/2022] [Indexed: 02/04/2023] Open
Abstract
In this review, we provide recent data on the role of mTOR kinase in the brain under physiological conditions and after damage, with a particular focus on cerebral ischemia. We cover the upstream and downstream pathways that regulate the activation state of mTOR complexes. Furthermore, we summarize recent advances in our understanding of mTORC1 and mTORC2 status in ischemia–hypoxia at tissue and cellular levels and analyze the existing evidence related to two types of neural cells, namely glia and neurons. Finally, we discuss the potential use of mTORC1 and mTORC2 as therapeutic targets after stroke.
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Affiliation(s)
- Mario Villa-González
- Departamento de Biología (Fisiología Animal), Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (M.V.-G.); (G.M.-L.)
- Centro de Biología Molecular “Severo Ochoa” (CBMSO), Universidad Autónoma de Madrid/CSIC, 28049 Madrid, Spain
| | - Gerardo Martín-López
- Departamento de Biología (Fisiología Animal), Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (M.V.-G.); (G.M.-L.)
| | - María José Pérez-Álvarez
- Departamento de Biología (Fisiología Animal), Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (M.V.-G.); (G.M.-L.)
- Centro de Biología Molecular “Severo Ochoa” (CBMSO), Universidad Autónoma de Madrid/CSIC, 28049 Madrid, Spain
- Correspondence: ; Tel.: +34-91-497-2819
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9
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Li Z, Qian W, Song W, Zhao T, Yang Y, Wang W, Wei L, Zhao D, Li Y, Perrimon N, Xia Q, Cheng D. A salivary gland-secreted peptide regulates insect systemic growth. Cell Rep 2022; 38:110397. [PMID: 35196492 DOI: 10.1016/j.celrep.2022.110397] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 11/10/2021] [Accepted: 01/26/2022] [Indexed: 11/03/2022] Open
Abstract
Insect salivary glands have been previously shown to function in pupal attachment and food lubrication by secreting factors into the lumen via an exocrine way. Here, we find in Drosophila that a salivary gland-derived secreted factor (Sgsf) peptide regulates systemic growth via an endocrine way. Sgsf is specifically expressed in salivary glands and secreted into the hemolymph. Sgsf knockout or salivary gland-specific Sgsf knockdown decrease the size of both the body and organs, phenocopying the effects of genetic ablation of salivary glands, while salivary gland-specific Sgsf overexpression increases their size. Sgsf promotes systemic growth by modulating the secretion of the insulin-like peptide Dilp2 from the brain insulin-producing cells (IPCs) and affecting mechanistic target of rapamycin (mTOR) signaling in the fat body. Altogether, our study demonstrates that Sgsf mediates the roles of salivary glands in Drosophila systemic growth, establishing an endocrine function of salivary glands.
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Affiliation(s)
- Zheng Li
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Sericultural Science, Southwest University, Chongqing 400715, China
| | - Wenliang Qian
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Sericultural Science, Southwest University, Chongqing 400715, China
| | - Wei Song
- Medical Research Institute, Wuhan University, Wuhan 430071, China; Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Tujing Zhao
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Sericultural Science, Southwest University, Chongqing 400715, China
| | - Yan Yang
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Sericultural Science, Southwest University, Chongqing 400715, China
| | - Weina Wang
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Sericultural Science, Southwest University, Chongqing 400715, China
| | - Ling Wei
- School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Dongchao Zhao
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Sericultural Science, Southwest University, Chongqing 400715, China
| | - Yaoyao Li
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Sericultural Science, Southwest University, Chongqing 400715, China
| | - Norbert Perrimon
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute, Boston, MA 02115, USA.
| | - Qingyou Xia
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Sericultural Science, Southwest University, Chongqing 400715, China.
| | - Daojun Cheng
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Sericultural Science, Southwest University, Chongqing 400715, China.
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10
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Sechi S, Karimpour-Ghahnavieh A, Frappaolo A, Di Francesco L, Piergentili R, Schininà E, D’Avino PP, Giansanti MG. Identification of GOLPH3 Partners in Drosophila Unveils Potential Novel Roles in Tumorigenesis and Neural Disorders. Cells 2021; 10:cells10092336. [PMID: 34571985 PMCID: PMC8468827 DOI: 10.3390/cells10092336] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 09/01/2021] [Accepted: 09/03/2021] [Indexed: 12/28/2022] Open
Abstract
Golgi phosphoprotein 3 (GOLPH3) is a highly conserved peripheral membrane protein localized to the Golgi apparatus and the cytosol. GOLPH3 binding to Golgi membranes depends on phosphatidylinositol 4-phosphate [PI(4)P] and regulates Golgi architecture and vesicle trafficking. GOLPH3 overexpression has been correlated with poor prognosis in several cancers, but the molecular mechanisms that link GOLPH3 to malignant transformation are poorly understood. We recently showed that PI(4)P-GOLPH3 couples membrane trafficking with contractile ring assembly during cytokinesis in dividing Drosophila spermatocytes. Here, we use affinity purification coupled with mass spectrometry (AP-MS) to identify the protein-protein interaction network (interactome) of Drosophila GOLPH3 in testes. Analysis of the GOLPH3 interactome revealed enrichment for proteins involved in vesicle-mediated trafficking, cell proliferation and cytoskeleton dynamics. In particular, we found that dGOLPH3 interacts with the Drosophila orthologs of Fragile X mental retardation protein and Ataxin-2, suggesting a potential role in the pathophysiology of disorders of the nervous system. Our findings suggest novel molecular targets associated with GOLPH3 that might be relevant for therapeutic intervention in cancers and other human diseases.
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Affiliation(s)
- Stefano Sechi
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (S.S.); (A.K.-G.); (A.F.); (R.P.)
| | - Angela Karimpour-Ghahnavieh
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (S.S.); (A.K.-G.); (A.F.); (R.P.)
| | - Anna Frappaolo
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (S.S.); (A.K.-G.); (A.F.); (R.P.)
| | - Laura Di Francesco
- Dipartimento di Scienze Biochimiche A. Rossi Fanelli, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (L.D.F.); (E.S.)
| | - Roberto Piergentili
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (S.S.); (A.K.-G.); (A.F.); (R.P.)
| | - Eugenia Schininà
- Dipartimento di Scienze Biochimiche A. Rossi Fanelli, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (L.D.F.); (E.S.)
| | - Pier Paolo D’Avino
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK;
| | - Maria Grazia Giansanti
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (S.S.); (A.K.-G.); (A.F.); (R.P.)
- Correspondence: ; Tel.: +39-064-991-2555
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11
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Ghomlaghi M, Yang G, Shin SY, James DE, Nguyen LK. Dynamic modelling of the PI3K/MTOR signalling network uncovers biphasic dependence of mTORC1 activity on the mTORC2 subunit SIN1. PLoS Comput Biol 2021; 17:e1008513. [PMID: 34529665 PMCID: PMC8478217 DOI: 10.1371/journal.pcbi.1008513] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 09/28/2021] [Accepted: 09/03/2021] [Indexed: 11/18/2022] Open
Abstract
The PI3K/MTOR signalling network regulates a broad array of critical cellular processes, including cell growth, metabolism and autophagy. The mechanistic target of rapamycin (MTOR) kinase functions as a core catalytic subunit in two physically and functionally distinct complexes mTORC1 and mTORC2, which also share other common components including MLST8 (also known as GβL) and DEPTOR. Despite intensive research, how mTORC1 and 2 assembly and activity are coordinated, and how they are functionally linked remain to be fully characterized. This is due in part to the complex network wiring, featuring multiple feedback loops and intricate post-translational modifications. Here, we integrate predictive network modelling, in vitro experiments and -omics data analysis to elucidate the emergent dynamic behaviour of the PI3K/MTOR network. We construct new mechanistic models that encapsulate critical mechanistic details, including mTORC1/2 coordination by MLST8 (de)ubiquitination and the Akt-to-mTORC2 positive feedback loop. Model simulations validated by experimental studies revealed a previously unknown biphasic, threshold-gated dependence of mTORC1 activity on the key mTORC2 subunit SIN1, which is robust against cell-to-cell variation in protein expression. In addition, our integrative analysis demonstrates that ubiquitination of MLST8, which is reversed by OTUD7B, is regulated by IRS1/2. Our results further support the essential role of MLST8 in enabling both mTORC1 and 2's activity and suggest MLST8 as a viable therapeutic target in breast cancer. Overall, our study reports a new mechanistic model of PI3K/MTOR signalling incorporating MLST8-mediated mTORC1/2 formation and unveils a novel regulatory linkage between mTORC1 and mTORC2.
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Affiliation(s)
- Milad Ghomlaghi
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Melbourne, Australia
- Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Guang Yang
- Charles Perkins Centre, School of Life and Environmental Sciences, The University of Sydney, Sydney, Australia
| | - Sung-Young Shin
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Melbourne, Australia
- Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - David E. James
- Charles Perkins Centre, School of Life and Environmental Sciences, The University of Sydney, Sydney, Australia
| | - Lan K. Nguyen
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Melbourne, Australia
- Biomedicine Discovery Institute, Monash University, Melbourne, Australia
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12
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Roles of PINK1 in regulation of systemic growth inhibition induced by mutations of PTEN in Drosophila. Cell Rep 2021; 34:108875. [PMID: 33761355 DOI: 10.1016/j.celrep.2021.108875] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 10/27/2020] [Accepted: 02/25/2021] [Indexed: 01/04/2023] Open
Abstract
The maintenance of mitochondrial homeostasis requires PTEN-induced kinase 1 (PINK1)-dependent mitophagy, and mutations in PINK1 are associated with Parkinson's disease (PD). PINK1 is also downregulated in tumor cells with PTEN mutations. However, there is limited information concerning the role of PINK1 in tissue growth and tumorigenesis. Here, we show that the loss of pink1 caused multiple growth defects independent of its pathological target, Parkin. Moreover, knocking down pink1 in muscle cells induced hyperglycemia and limited systemic organismal growth by the induction of Imaginal morphogenesis protein-Late 2 (ImpL2). Similarly, disrupting PTEN activity in multiple tissues impaired systemic growth by reducing pink1 expression, resembling wasting-like syndrome in cancer patients. Furthermore, the re-expression of PINK1 fully rescued defects in carbohydrate metabolism and systemic growth induced by the tissue-specific pten mutations. Our data suggest a function for PINK1 in regulating systemic growth in Drosophila and shed light on its role in wasting in the context of PTEN mutations.
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13
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Texada MJ, Koyama T, Rewitz K. Regulation of Body Size and Growth Control. Genetics 2020; 216:269-313. [PMID: 33023929 PMCID: PMC7536854 DOI: 10.1534/genetics.120.303095] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 06/29/2020] [Indexed: 12/20/2022] Open
Abstract
The control of body and organ growth is essential for the development of adults with proper size and proportions, which is important for survival and reproduction. In animals, adult body size is determined by the rate and duration of juvenile growth, which are influenced by the environment. In nutrient-scarce environments in which more time is needed for growth, the juvenile growth period can be extended by delaying maturation, whereas juvenile development is rapidly completed in nutrient-rich conditions. This flexibility requires the integration of environmental cues with developmental signals that govern internal checkpoints to ensure that maturation does not begin until sufficient tissue growth has occurred to reach a proper adult size. The Target of Rapamycin (TOR) pathway is the primary cell-autonomous nutrient sensor, while circulating hormones such as steroids and insulin-like growth factors are the main systemic regulators of growth and maturation in animals. We discuss recent findings in Drosophila melanogaster showing that cell-autonomous environment and growth-sensing mechanisms, involving TOR and other growth-regulatory pathways, that converge on insulin and steroid relay centers are responsible for adjusting systemic growth, and development, in response to external and internal conditions. In addition to this, proper organ growth is also monitored and coordinated with whole-body growth and the timing of maturation through modulation of steroid signaling. This coordination involves interorgan communication mediated by Drosophila insulin-like peptide 8 in response to tissue growth status. Together, these multiple nutritional and developmental cues feed into neuroendocrine hubs controlling insulin and steroid signaling, serving as checkpoints at which developmental progression toward maturation can be delayed. This review focuses on these mechanisms by which external and internal conditions can modulate developmental growth and ensure proper adult body size, and highlights the conserved architecture of this system, which has made Drosophila a prime model for understanding the coordination of growth and maturation in animals.
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Affiliation(s)
| | - Takashi Koyama
- Department of Biology, University of Copenhagen, 2100, Denmark
| | - Kim Rewitz
- Department of Biology, University of Copenhagen, 2100, Denmark
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14
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Cell-Size Pleomorphism Drives Aberrant Clone Dispersal in Proliferating Epithelia. Dev Cell 2019; 51:49-61.e4. [PMID: 31495693 DOI: 10.1016/j.devcel.2019.08.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 06/18/2019] [Accepted: 08/06/2019] [Indexed: 11/22/2022]
Abstract
As epithelial tissues develop, groups of cells related by descent tend to associate in clonal populations rather than dispersing within the cell layer. While this is frequently assumed to be a result of differential adhesion, precise mechanisms controlling clonal cohesiveness remain unknown. Here we employ computational simulations to modulate epithelial cell size in silico and show that junctions between small cells frequently collapse, resulting in clone-cell dispersal among larger neighbors. Consistent with similar dynamics in vivo, we further demonstrate that mosaic disruption of Drosophila Tor generates small cells and results in aberrant clone dispersal in developing wing disc epithelia. We propose a geometric basis for this phenomenon, supported in part by the observation that soap-foam cells exhibit similar size-dependent junctional rearrangements. Combined, these results establish a link between cell-size pleomorphism and the control of epithelial cell packing, with potential implications for understanding tumor cell dispersal in human disease.
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15
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Yue Z, Lv Z, Shao Y, Zhang W, Zhao X, Guo M, Li C. Cloning and characterization of the target protein subunit lst8 of rapamycin in Apostichopus japonicus. FISH & SHELLFISH IMMUNOLOGY 2019; 92:460-468. [PMID: 31233778 DOI: 10.1016/j.fsi.2019.06.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Revised: 06/14/2019] [Accepted: 06/17/2019] [Indexed: 06/09/2023]
Abstract
Autophagy plays an important role in the immune defense systems of vertebrates through the interaction between the lethal with SEC13 protein 8 (lst8) and the mechanistic target of rapamycin. In the present study, a novel invertebrate lst8 homologue is identified from Apostichopus japonicus (designated as Ajlst8) via polymerase chain reaction. The full-length complementary DNA of Ajlst8 comprises a 5'-untranslated region (UTR) of 78 base pair (bp), a 3'-UTR of 479 bp, and a putative open reading frame of 951 bp; hence, 316 amino acids are encoded. Structural analysis shows that the deduced amino acid of Ajlst8 shares six typical WD40 domains (28 aa-248 aa). Spatial expression analysis indicates that Ajlst8 is ubiquitously expressed in all the examined tissues, with a larger magnitude in coelomocytes. Vibrio splendidus infection in vivo and lipopolysaccharide exposure in vitro can significantly upregulate the messenger RNA expression of Ajlst8 by 2.39-fold and 1.93-fold compared with the control group, respectively. LPS exposure could also significantly induced the protein level of Ajlst8 to 2.38-fold and the autophagy level was markedly increased by 3.08-fold under same condition. The RNA interference of Ajlst8 in primary coelomocytes also reduces the relative expression of autophagy with a 0.71-fold decrease in the ratio of LC3-II/LC3-I compared with that in the control group. These results indicate that Ajlst8 is a novel immune regulator that may be involved in the antibacterial response process of sea cucumber by regulating autophagy.
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Affiliation(s)
- Zongxu Yue
- State Key Laboratory for Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China
| | - Zhimeng Lv
- State Key Laboratory for Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China
| | - Yina Shao
- State Key Laboratory for Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China
| | - Weiwei Zhang
- State Key Laboratory for Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China
| | - Xuelin Zhao
- State Key Laboratory for Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China
| | - Ming Guo
- State Key Laboratory for Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China
| | - Chenghua Li
- State Key Laboratory for Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, PR China.
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16
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Hwang Y, Kim LC, Song W, Edwards DN, Cook RS, Chen J. Disruption of the Scaffolding Function of mLST8 Selectively Inhibits mTORC2 Assembly and Function and Suppresses mTORC2-Dependent Tumor Growth In Vivo. Cancer Res 2019; 79:3178-3184. [PMID: 31085701 DOI: 10.1158/0008-5472.can-18-3658] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 04/05/2019] [Accepted: 05/08/2019] [Indexed: 12/24/2022]
Abstract
mTOR is a serine/threonine kinase that acts in two distinct complexes, mTORC1 and mTORC2, and is dysregulated in many diseases including cancer. mLST8 is a shared component of both mTORC1 and mTORC2, yet little is known regarding how mLST8 contributes to assembly and activity of the mTOR complexes. Here we assessed mLST8 loss in a panel of normal and cancer cells and observed little to no impact on assembly or activity of mTORC1. However, mLST8 loss blocked mTOR association with mTORC2 cofactors RICTOR and SIN1, thus abrogating mTORC2 activity. Similarly, a single pair of mutations on mLST8 with a corresponding mutation on mTOR interfered with mTORC2 assembly and activity without affecting mTORC1. We also discovered a direct interaction between mLST8 and the NH2-terminal domain of the mTORC2 cofactor SIN1. In PTEN-null prostate cancer xenografts, mLST8 mutations disrupting the mTOR interaction motif inhibited AKT S473 phosphorylation and decreased tumor cell proliferation and tumor growth in vivo. Together, these data suggest that the scaffolding function of mLST8 is critical for assembly and activity of mTORC2, but not mTORC1, an observation that could enable therapeutic mTORC2-selective inhibition as a therapeutic strategy. SIGNIFICANCE: These findings show that mLST8 functions as a scaffold to maintain mTORC2 integrity and kinase activity, unveiling a new avenue for development of mTORC2-specific inhibitors.
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Affiliation(s)
- Yoonha Hwang
- Veterans Affairs Medical Center, Tennessee Valley Healthcare System, Nashville, Tennessee
- Division of Rheumatology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Laura C Kim
- Program in Cancer Biology, Vanderbilt University, Nashville, Tennessee
| | - Wenqiang Song
- Veterans Affairs Medical Center, Tennessee Valley Healthcare System, Nashville, Tennessee
- Division of Rheumatology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Deanna N Edwards
- Veterans Affairs Medical Center, Tennessee Valley Healthcare System, Nashville, Tennessee
- Division of Rheumatology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Rebecca S Cook
- Program in Cancer Biology, Vanderbilt University, Nashville, Tennessee
- Deparment of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
- Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee
| | - Jin Chen
- Veterans Affairs Medical Center, Tennessee Valley Healthcare System, Nashville, Tennessee.
- Division of Rheumatology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee
- Program in Cancer Biology, Vanderbilt University, Nashville, Tennessee
- Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee
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17
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Chen X, Dickman D. Development of a tissue-specific ribosome profiling approach in Drosophila enables genome-wide evaluation of translational adaptations. PLoS Genet 2017; 13:e1007117. [PMID: 29194454 PMCID: PMC5728580 DOI: 10.1371/journal.pgen.1007117] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 12/13/2017] [Accepted: 11/16/2017] [Indexed: 01/19/2023] Open
Abstract
Recent advances in next-generation sequencing approaches have revolutionized our understanding of transcriptional expression in diverse systems. However, measurements of transcription do not necessarily reflect gene translation, the process of ultimate importance in understanding cellular function. To circumvent this limitation, biochemical tagging of ribosome subunits to isolate ribosome-associated mRNA has been developed. However, this approach, called TRAP, lacks quantitative resolution compared to a superior technology, ribosome profiling. Here, we report the development of an optimized ribosome profiling approach in Drosophila. We first demonstrate successful ribosome profiling from a specific tissue, larval muscle, with enhanced resolution compared to conventional TRAP approaches. We next validate the ability of this technology to define genome-wide translational regulation. This technology is leveraged to test the relative contributions of transcriptional and translational mechanisms in the postsynaptic muscle that orchestrate the retrograde control of presynaptic function at the neuromuscular junction. Surprisingly, we find no evidence that significant changes in the transcription or translation of specific genes are necessary to enable retrograde homeostatic signaling, implying that post-translational mechanisms ultimately gate instructive retrograde communication. Finally, we show that a global increase in translation induces adaptive responses in both transcription and translation of protein chaperones and degradation factors to promote cellular proteostasis. Together, this development and validation of tissue-specific ribosome profiling enables sensitive and specific analysis of translation in Drosophila. Recent advances in next-generation sequencing approaches have revolutionized our understanding of transcriptional expression in diverse systems. However, transcriptional expression alone does not necessarily report gene translation, the process of ultimate importance in understanding cellular function. Ribosome profiling is a powerful approach to quantify the number of ribosomes associated with each mRNA to determine rates of gene translation. However, ribosome profiling requires large quantities of starting material, limiting progress in developing tissue-specific approaches. Here, we have developed the first tissue-specific ribosome profiling system in Drosophila to reveal genome-wide changes in translation. We first demonstrate successful ribosome profiling from muscle cells that exhibit superior resolution compared to other translational profiling methods. We then use transcriptional and ribosome profiling to define whether transcriptional or translational mechanisms are necessary for synaptic signaling at the neuromuscular junction. Finally, we utilize ribosome profiling to reveal adaptive changes in cellular translation following cellular stress to muscle tissue. Together, this now enables the power of Drosophila genetics to be leveraged with ribosome profiling in specific tissues.
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Affiliation(s)
- Xun Chen
- Department of Neurobiology, University of Southern California, Los Angeles, California, United States of America
- USC Neuroscience Graduate Program, University of Southern California, Los Angeles, California, United States of America
| | - Dion Dickman
- Department of Neurobiology, University of Southern California, Los Angeles, California, United States of America
- * E-mail:
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18
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Ren S, Huang Z, Jiang Y, Wang T. dTBC1D7 regulates systemic growth independently of TSC through insulin signaling. J Cell Biol 2017; 217:517-526. [PMID: 29187524 PMCID: PMC5800808 DOI: 10.1083/jcb.201706027] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 10/10/2017] [Accepted: 11/08/2017] [Indexed: 12/31/2022] Open
Abstract
The insulin signaling pathway plays key roles in systemic growth. TBC1D7 has recently been identified as the third subunit of the tuberous sclerosis complex (TSC), a negative regulator of cell growth. Here, we used Drosophila as a model system to dissect the physiological function of TBC1D7 in vivo. In mutants lacking TBC1D7, cell and organ growth were promoted, and TBC1D7 limited cell growth in a cell-nonautonomous and TSC-independent manner. TBC1D7 is specifically expressed in insulin-producing cells in the fly brain and regulated biosynthesis and release of insulin-like peptide 2, leading to systemic growth. Furthermore, animals carrying the dTBC1D7 mutation were hypoglycemic, short-lived, and sensitive to oxidative stress. Our findings provide new insights into the physiological function of TBC1D7 in the systemic control of growth, as well as insights into human disorders caused by TBC1D7 mutation.
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Affiliation(s)
- Suxia Ren
- College of Biological Sciences, China Agricultural University, Beijing, China.,National Institute of Biological Sciences, Beijing, China
| | - Zengyi Huang
- National Institute of Biological Sciences, Beijing, China.,State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yuqiang Jiang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Tao Wang
- National Institute of Biological Sciences, Beijing, China
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19
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Abstract
Cell size is amenable by genetic and environmental factors. The highly conserved nutrient-responsive Target of Rapamycin (TOR) signaling pathway regulates cellular metabolic status and growth in response to numerous inputs. Timing and duration of TOR pathway activity is pivotal for both cell mass built up as well as cell cycle progression and is controlled and fine-tuned by the abundance and quality of nutrients, hormonal signals, growth factors, stress, and oxygen. TOR kinases function within two functionally and structurally discrete multiprotein complexes, TORC1 and TORC2, that are implicated in temporal and spatial control of cell size and growth respectively; however, recent data indicate that such functional distinctions are much more complex. Here, we briefly review roles of the two complexes in cellular growth and cytoarchitecture in various experimental model systems.
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Affiliation(s)
- Suam Gonzalez
- School of Health, Sport and Bioscience, University of East LondonLondon, United Kingdom
| | - Charalampos Rallis
- School of Health, Sport and Bioscience, University of East LondonLondon, United Kingdom
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20
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Lee PL, Jung SM, Guertin DA. The Complex Roles of Mechanistic Target of Rapamycin in Adipocytes and Beyond. Trends Endocrinol Metab 2017; 28:319-339. [PMID: 28237819 PMCID: PMC5682923 DOI: 10.1016/j.tem.2017.01.004] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 01/20/2017] [Accepted: 01/23/2017] [Indexed: 01/01/2023]
Abstract
Having healthy adipose tissue is essential for metabolic fitness. This is clear from the obesity epidemic, which is unveiling a myriad of comorbidities associated with excess adipose tissue including type 2 diabetes, cardiovascular disease, and cancer. Lipodystrophy also causes insulin resistance, emphasizing the importance of having a balanced amount of fat. In cells, the mechanistic target of rapamycin (mTOR) complexes 1 and 2 (mTORC1 and mTORC2, respectively) link nutrient and hormonal signaling with metabolism, and recent studies are shedding new light on their in vivo roles in adipocytes. In this review, we discuss how recent advances in adipose tissue and mTOR biology are converging to reveal new mechanisms that maintain healthy adipose tissue, and discuss ongoing mysteries of mTOR signaling, particularly for the less understood complex mTORC2.
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Affiliation(s)
- Peter L Lee
- Program in Molecular Medicine, University of Massachusetts Medical School, 373 Plantation Street, Worcester, MA 01605, USA
| | - Su Myung Jung
- Program in Molecular Medicine, University of Massachusetts Medical School, 373 Plantation Street, Worcester, MA 01605, USA
| | - David A Guertin
- Program in Molecular Medicine, University of Massachusetts Medical School, 373 Plantation Street, Worcester, MA 01605, USA.
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21
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David-Morrison G, Xu Z, Rui YN, Charng WL, Jaiswal M, Yamamoto S, Xiong B, Zhang K, Sandoval H, Duraine L, Zuo Z, Zhang S, Bellen HJ. WAC Regulates mTOR Activity by Acting as an Adaptor for the TTT and Pontin/Reptin Complexes. Dev Cell 2016; 36:139-151. [PMID: 26812014 PMCID: PMC4730548 DOI: 10.1016/j.devcel.2015.12.019] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 10/16/2015] [Accepted: 12/18/2015] [Indexed: 01/09/2023]
Abstract
The ability to sense energy status is crucial in the regulation of metabolism via the mechanistic Target of Rapamycin Complex 1 (mTORC1). The assembly of the TTT-Pontin/Reptin complex is responsive to changes in energy status. Under energy-sufficient conditions, the TTT-Pontin/Reptin complex promotes mTORC1 dimerization and mTORC1-Rag interaction, which are critical for mTORC1 activation. We show that WAC is a regulator of energy-mediated mTORC1 activity. In a Drosophila screen designed to isolate mutations that cause neuronal dysfunction, we identified wacky, the homolog of WAC. Loss of Wacky leads to neurodegeneration, defective mTOR activity, and increased autophagy. Wacky and WAC have conserved physical interactions with mTOR and its regulators, including Pontin and Reptin, which bind to the TTT complex to regulate energy-dependent activation of mTORC1. WAC promotes the interaction between TTT and Pontin/Reptin in an energy-dependent manner, thereby promoting mTORC1 activity by facilitating mTORC1 dimerization and mTORC1-Rag interaction.
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Affiliation(s)
| | - Zhen Xu
- The Brown Foundation Institute of Molecular Medicine, The University of Texas Medical School at Houston, Houston, TX 77030, USA
| | - Yan-Ning Rui
- The Brown Foundation Institute of Molecular Medicine, The University of Texas Medical School at Houston, Houston, TX 77030, USA
| | - Wu-Lin Charng
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Manish Jaiswal
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA
| | - Shinya Yamamoto
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Bo Xiong
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ke Zhang
- Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hector Sandoval
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Lita Duraine
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zhongyuan Zuo
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Sheng Zhang
- The Brown Foundation Institute of Molecular Medicine, The University of Texas Medical School at Houston, Houston, TX 77030, USA; Department of Neurobiology and Anatomy, The University of Texas Medical School at Houston, Houston, TX 77030, USA; Programs in Human and Molecular Genetics and Neuroscience, The Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX 77030, USA.
| | - Hugo J Bellen
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, TX 77030, USA.
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22
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Blackwell TK, Steinbaugh MJ, Hourihan JM, Ewald CY, Isik M. SKN-1/Nrf, stress responses, and aging in Caenorhabditis elegans. Free Radic Biol Med 2015; 88:290-301. [PMID: 26232625 PMCID: PMC4809198 DOI: 10.1016/j.freeradbiomed.2015.06.008] [Citation(s) in RCA: 428] [Impact Index Per Article: 42.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 06/17/2015] [Accepted: 06/18/2015] [Indexed: 01/06/2023]
Abstract
The mammalian Nrf/CNC proteins (Nrf1, Nrf2, Nrf3, p45 NF-E2) perform a wide range of cellular protective and maintenance functions. The most thoroughly described of these proteins, Nrf2, is best known as a regulator of antioxidant and xenobiotic defense, but more recently has been implicated in additional functions that include proteostasis and metabolic regulation. In the nematode Caenorhabditis elegans, which offers many advantages for genetic analyses, the Nrf/CNC proteins are represented by their ortholog SKN-1. Although SKN-1 has diverged in aspects of how it binds DNA, it exhibits remarkable functional conservation with Nrf/CNC proteins in other species and regulates many of the same target gene families. C. elegans may therefore have considerable predictive value as a discovery model for understanding how mammalian Nrf/CNC proteins function and are regulated in vivo. Work in C. elegans indicates that SKN-1 regulation is surprisingly complex and is influenced by numerous growth, nutrient, and metabolic signals. SKN-1 is also involved in a wide range of homeostatic functions that extend well beyond the canonical Nrf2 function in responses to acute stress. Importantly, SKN-1 plays a central role in diverse genetic and pharmacologic interventions that promote C. elegans longevity, suggesting that mechanisms regulated by SKN-1 may be of conserved importance in aging. These C. elegans studies predict that mammalian Nrf/CNC protein functions and regulation may be similarly complex and that the proteins and processes that they regulate are likely to have a major influence on mammalian life- and healthspan.
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Affiliation(s)
- T Keith Blackwell
- Research Division, Joslin Diabetes Center, One Joslin Place, Boston, MA 02215, USA; Department of Genetics and Harvard Stem Cell Institute, Harvard Medical School, Boston, MA 02215, USA.
| | - Michael J Steinbaugh
- Research Division, Joslin Diabetes Center, One Joslin Place, Boston, MA 02215, USA; Department of Genetics and Harvard Stem Cell Institute, Harvard Medical School, Boston, MA 02215, USA
| | - John M Hourihan
- Research Division, Joslin Diabetes Center, One Joslin Place, Boston, MA 02215, USA; Department of Genetics and Harvard Stem Cell Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Collin Y Ewald
- Research Division, Joslin Diabetes Center, One Joslin Place, Boston, MA 02215, USA; Department of Genetics and Harvard Stem Cell Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Meltem Isik
- Research Division, Joslin Diabetes Center, One Joslin Place, Boston, MA 02215, USA; Department of Genetics and Harvard Stem Cell Institute, Harvard Medical School, Boston, MA 02215, USA
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23
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Jevtov I, Zacharogianni M, van Oorschot MM, van Zadelhoff G, Aguilera-Gomez A, Vuillez I, Braakman I, Hafen E, Stocker H, Rabouille C. TORC2 mediates the heat stress response in Drosophila by promoting the formation of stress granules. J Cell Sci 2015; 128:2497-508. [PMID: 26054799 PMCID: PMC4510851 DOI: 10.1242/jcs.168724] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 06/03/2015] [Indexed: 12/29/2022] Open
Abstract
The kinase TOR is found in two complexes, TORC1, which is involved in growth control, and TORC2, whose roles are less well defined. Here, we asked whether TORC2 has a role in sustaining cellular stress. We show that TORC2 inhibition in Drosophila melanogaster leads to a reduced tolerance to heat stress, whereas sensitivity to other stresses is not affected. Accordingly, we show that upon heat stress, both in the animal and Drosophila cultured S2 cells, TORC2 is activated and is required for maintaining the level of its known target, Akt1 (also known as PKB). We show that the phosphorylation of the stress-activated protein kinases is not modulated by TORC2 nor is the heat-induced upregulation of heat-shock proteins. Instead, we show, both in vivo and in cultured cells, that TORC2 is required for the assembly of heat-induced cytoprotective ribonucleoprotein particles, the pro-survival stress granules. These granules are formed in response to protein translation inhibition imposed by heat stress that appears to be less efficient in the absence of TORC2 function. We propose that TORC2 mediates heat resistance in Drosophila by promoting the cell autonomous formation of stress granules.
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Affiliation(s)
- Irena Jevtov
- Institute of Molecular Systems Biology, ETH Zurich, Zurich 8093, Switzerland
| | | | - Marinke M van Oorschot
- Hubrecht Institute of the KNAW and UMC Utrecht, Uppsalalaan 8, Utrecht 3584 CT, Netherlands
| | - Guus van Zadelhoff
- Cellular Protein Chemistry, Utrecht University, Padualaan 8, Utrecht 3584 CH, The Netherlands
| | | | - Igor Vuillez
- Institute of Molecular Systems Biology, ETH Zurich, Zurich 8093, Switzerland
| | - Ineke Braakman
- Cellular Protein Chemistry, Utrecht University, Padualaan 8, Utrecht 3584 CH, The Netherlands
| | - Ernst Hafen
- Institute of Molecular Systems Biology, ETH Zurich, Zurich 8093, Switzerland
| | - Hugo Stocker
- Institute of Molecular Systems Biology, ETH Zurich, Zurich 8093, Switzerland
| | - Catherine Rabouille
- Hubrecht Institute of the KNAW and UMC Utrecht, Uppsalalaan 8, Utrecht 3584 CT, Netherlands Department of Cell Biology, UMC Utrecht, Heidelberglaan 100, Utrecht 3584 CX, The Netherlands
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24
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Kuo Y, Huang H, Cai T, Wang T. Target of Rapamycin Complex 2 regulates cell growth via Myc in Drosophila. Sci Rep 2015; 5:10339. [PMID: 25999153 PMCID: PMC4441130 DOI: 10.1038/srep10339] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Accepted: 04/10/2015] [Indexed: 12/24/2022] Open
Abstract
Target of rapamycin (TOR) is an evolutionarily conserved serine/threonine protein kinase that functions as a central regulator of cellular growth and metabolism by forming two distinct complexes: TOR complex 1 (TORC1) and TORC2. As well as TORC1, TORC2 plays a key role in regulation of cell growth. But little is known about how TORC2 regulates cell growth. The transcription factor Myc also plays a critical role in cell proliferation and growth. Here we report that TORC2 and Myc regulate cell growth via a common pathway. Expression of Myc fully rescued growth defects associated with lst8 and rictor mutations, both of which encode essential components of TORC2. Furthermore, loss of TORC2 disrupted the nuclear localization of Myc, and inhibited Myc-dependent transcription. Together, our results reveal a Myc-dependent pathway by which TORC2 regulates cell growth.
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Affiliation(s)
- Ying Kuo
- National Institute of Biological Sciences, Beijing, China
| | - Huanwei Huang
- National Institute of Biological Sciences, Beijing, China
| | - Tao Cai
- National Institute of Biological Sciences, Beijing, China
| | - Tao Wang
- National Institute of Biological Sciences, Beijing, China
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25
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Mizunuma M, Neumann‐Haefelin E, Moroz N, Li Y, Blackwell TK. mTORC2-SGK-1 acts in two environmentally responsive pathways with opposing effects on longevity. Aging Cell 2014; 13:869-78. [PMID: 25040785 PMCID: PMC4172656 DOI: 10.1111/acel.12248] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/11/2014] [Indexed: 01/22/2023] Open
Abstract
The nematode worm Caenorhabditis elegans provides a powerful system for elucidating how genetic, metabolic, nutritional, and environmental factors influence aging. The mechanistic target of rapamycin (mTOR) kinase is important in growth, disease, and aging and is present in the mTORC1 and mTORC2 complexes. In diverse eukaryotes, lifespan can be increased by inhibition of mTORC1, which transduces anabolic signals to stimulate protein synthesis and inhibit autophagy. Less is understood about mTORC2, which affects C. elegans lifespan in a complex manner that is influenced by the bacterial food source. mTORC2 regulates C. elegans growth, reproduction, and lipid metabolism by activating the SGK-1 kinase, but current data on SGK-1 and lifespan seem to be conflicting. Here, by analyzing the mTORC2 component Rictor (RICT-1), we show that mTORC2 modulates longevity by activating SGK-1 in two pathways that affect lifespan oppositely. RICT-1/mTORC2 limits longevity by directing SGK-1 to inhibit the stress-response transcription factor SKN-1/Nrf in the intestine. Signals produced by the bacterial food source determine how this pathway affects SKN-1 and lifespan. In addition, RICT-1/mTORC2 functions in neurons in an SGK-1-mediated pathway that increases lifespan at lower temperatures. RICT-1/mTORC2 and SGK-1 therefore oppose or accelerate aging depending upon the context in which they are active. Our findings reconcile data on SGK-1 and aging, show that the bacterial microenvironment influences SKN-1/Nrf, mTORC2 functions, and aging, and identify two longevity-related mTORC2 functions that involve SGK-regulated responses to environmental cues.
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Affiliation(s)
- Masaki Mizunuma
- Joslin Diabetes Center Harvard Stem Cell Institute Harvard Medical School Department of Genetics Boston MA 02215USA
- Department of Molecular Biotechnology Graduate School of Advanced Sciences of Matter Hiroshima University Higashi‐Hiroshima 739‐8530 Japan
| | - Elke Neumann‐Haefelin
- Joslin Diabetes Center Harvard Stem Cell Institute Harvard Medical School Department of Genetics Boston MA 02215USA
- Renal Division University Hospital Freiburg Freiburg 79106Germany
| | - Natalie Moroz
- Joslin Diabetes Center Harvard Stem Cell Institute Harvard Medical School Department of Genetics Boston MA 02215USA
- Division of Biological Sciences Department of Genetics and Complex Diseases Harvard School of Public Health Boston MA 02115USA
| | - Yujie Li
- Renal Division University Hospital Freiburg Freiburg 79106Germany
| | - T. Keith Blackwell
- Joslin Diabetes Center Harvard Stem Cell Institute Harvard Medical School Department of Genetics Boston MA 02215USA
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26
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Xie J, Proud CG. Signaling crosstalk between the mTOR complexes. ACTA ACUST UNITED AC 2014; 2:e28174. [PMID: 26779402 PMCID: PMC4705829 DOI: 10.4161/trla.28174] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 01/12/2014] [Accepted: 02/10/2014] [Indexed: 12/16/2022]
Abstract
mTOR is a protein kinase which integrates a variety of environmental and intracellular stimuli to positively regulate many anabolic processes of the cell, including protein synthesis. It exists within two highly conserved multi-protein complexes known as mTORC1 and 2 mTORC2. Each of these complexes phosphorylates different downstream targets, and play roles in different cellular functions. They also show distinctive sensitivity to the mTOR inhibitor rapamycin. Nevertheless, despite their biochemical and functional differences, recent studies have suggested that the regulation of these complexes is tightly linked to each other. For instance, both mTORC1 and 2 share some common upstream signaling molecules, such as PI3K and tuberous sclerosis complex TSC, which control their activation. Stimulation of the mTOR complexes may also trigger both positive and negative feedback mechanisms, which then in turn either further enhance or suppress their activation. Here, we summarize some recently discovered features relating to the crosstalk between mTORC1 and 2. We then discuss how aberrant mTOR complex crosstalk mechanisms may have an impact on the development of human diseases and drug resistance.
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Affiliation(s)
- Jianling Xie
- Centre for Biological Sciences; University of Southampton; Southampton, UK
| | - Chris G Proud
- Centre for Biological Sciences; University of Southampton; Southampton, UK
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27
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Kuo Y, Ren S, Lao U, Edgar BA, Wang T. Suppression of polyglutamine protein toxicity by co-expression of a heat-shock protein 40 and a heat-shock protein 110. Cell Death Dis 2013; 4:e833. [PMID: 24091676 PMCID: PMC3824661 DOI: 10.1038/cddis.2013.351] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 07/29/2013] [Accepted: 08/12/2013] [Indexed: 01/17/2023]
Abstract
A network of heat-shock proteins mediates cellular protein homeostasis, and has a fundamental role in preventing aggregation-associated neurodegenerative diseases. In a Drosophila model of polyglutamine (polyQ) disease, the HSP40 family protein, DNAJ-1, is a superior suppressor of toxicity caused by the aggregation of polyQ containing proteins. Here, we demonstrate that one specific HSP110 protein, 70 kDa heat-shock cognate protein cb (HSC70cb), interacts physically and genetically with DNAJ-1 in vivo, and that HSC70cb is necessary for DNAJ-1 to suppress polyglutamine-induced cell death in Drosophila. Expression of HSC70cb together with DNAJ-1 significantly enhanced the suppressive effects of DNAJ-1 on polyQ-induced neurodegeneration, whereas expression of HSC70cb alone did not suppress neurodegeneration in Drosophila models of either general polyQ disease or Huntington's disease. Furthermore, expression of a human HSP40, DNAJB1, together with a human HSP110, APG-1, protected cells from polyQ-induced neural degeneration in flies, whereas expression of either component alone had little effect. Our data provide a functional link between HSP40 and HSP110 in suppressing the cytotoxicity of aggregation-prone proteins, and suggest that HSP40 and HSP110 function together in protein homeostasis control.
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Affiliation(s)
- Y Kuo
- Division of Basic Sciences, National Institute of Biological Sciences, Beijing, China
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28
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Graber TE, McCamphill PK, Sossin WS. A recollection of mTOR signaling in learning and memory. Learn Mem 2013; 20:518-30. [PMID: 24042848 DOI: 10.1101/lm.027664.112] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Mechanistic target of rapamcyin (mTOR) is a central player in cell growth throughout the organism. However, mTOR takes on an additional, more specialized role in the developed neuron, where it regulates the protein synthesis-dependent, plastic changes underlying learning and memory. mTOR is sequestered in two multiprotein complexes (mTORC1 and mTORC2) that have different substrate specificities, thus allowing for distinct functions at synapses. We will examine how learning activates the mTOR complexes, survey the critical effectors of this pathway in the context of synaptic plasticity, and assess whether mTOR plays an instructive or permissive role in generating molecular memory traces.
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Affiliation(s)
- Tyson E Graber
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A-2B4, Canada
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29
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Ruf V, Holzem C, Peyman T, Walz G, Blackwell TK, Neumann-Haefelin E. TORC2 signaling antagonizes SKN-1 to induce C. elegans mesendodermal embryonic development. Dev Biol 2013; 384:214-27. [PMID: 23973804 DOI: 10.1016/j.ydbio.2013.08.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 08/12/2013] [Accepted: 08/13/2013] [Indexed: 01/18/2023]
Abstract
The evolutionarily conserved target of rapamycin (TOR) kinase controls fundamental metabolic processes to support cell and tissue growth. TOR functions within the context of two distinct complexes, TORC1 and TORC2. TORC2, with its specific component Rictor, has been recently implicated in aging and regulation of growth and metabolism. Here, we identify rict-1/Rictor as a regulator of embryonic development in C. elegans. The transcription factor skn-1 establishes development of the mesendoderm in embryos, and is required for cellular homeostasis and longevity in adults. Loss of maternal skn-1 function leads to mis-specification of the mesendodermal precursor and failure to form intestine and pharynx. We found that genetic inactivation of rict-1 suppressed skn-1-associated lethality by restoring mesendodermal specification in skn-1 deficient embryos. Inactivation of other TORC2 but not TORC1 components also partially rescued skn-1 embryonic lethality. The SGK-1 kinase mediated these functions downstream of rict-1/TORC2, as a sgk-1 gain-of-function mutant suppressed the rict-1 mutant phenotype. These data indicate that TORC2 and SGK-1 antagonize SKN-1 during embryonic development.
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Affiliation(s)
- Vanessa Ruf
- Department of Medicine, Renal Division, University Hospital Freiburg, D-79106 Freiburg, Germany
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30
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Abstract
The target of rapamycin (TOR) is a highly conserved serine/threonine kinase that is part of two structurally and functionally distinct complexes, TORC1 and TORC2. In multicellular organisms, TOR regulates cell growth and metabolism in response to nutrients, growth factors and cellular energy. Deregulation of TOR signaling alters whole body metabolism and causes age-related disease. This review describes the most recent advances in TOR signaling with a particular focus on mammalian TOR (mTOR) in metabolic tissues vis-a-vis aging, obesity, type 2 diabetes, and cancer.
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Affiliation(s)
- Marion Cornu
- Biozentrum, University of Basel, CH-4056 Basel, Switzerland
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31
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Cornu M, Albert V, Hall MN. mTOR in aging, metabolism, and cancer. Curr Opin Genet Dev 2013; 23:53-62. [PMID: 23317514 DOI: 10.1016/j.gde.2012.12.005] [Citation(s) in RCA: 354] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Revised: 12/04/2012] [Accepted: 12/12/2012] [Indexed: 12/19/2022]
Abstract
The target of rapamycin (TOR) is a highly conserved serine/threonine kinase that is part of two structurally and functionally distinct complexes, TORC1 and TORC2. In multicellular organisms, TOR regulates cell growth and metabolism in response to nutrients, growth factors and cellular energy. Deregulation of TOR signaling alters whole body metabolism and causes age-related disease. This review describes the most recent advances in TOR signaling with a particular focus on mammalian TOR (mTOR) in metabolic tissues vis-a-vis aging, obesity, type 2 diabetes, and cancer.
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Affiliation(s)
- Marion Cornu
- Biozentrum, University of Basel, CH-4056 Basel, Switzerland
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