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Tempes A, Bogusz K, Brzozowska A, Weslawski J, Macias M, Tkaczyk O, Orzoł K, Lew A, Calka-Kresa M, Bernas T, Szczepankiewicz AA, Mlostek M, Kumari S, Liszewska E, Machnicka K, Bakun M, Rubel T, Malik AR, Jaworski J. Autophagy initiation triggers p150 Glued-AP-2β interaction on the lysosomes and facilitates their transport. Cell Mol Life Sci 2024; 81:218. [PMID: 38758395 PMCID: PMC11101406 DOI: 10.1007/s00018-024-05256-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Revised: 01/25/2024] [Accepted: 04/15/2024] [Indexed: 05/18/2024]
Abstract
The endocytic adaptor protein 2 (AP-2) complex binds dynactin as part of its noncanonical function, which is necessary for dynein-driven autophagosome transport along microtubules in neuronal axons. The absence of this AP-2-dependent transport causes neuronal morphology simplification and neurodegeneration. The mechanisms that lead to formation of the AP-2-dynactin complex have not been studied to date. However, the inhibition of mammalian/mechanistic target of rapamycin complex 1 (mTORC1) enhances the transport of newly formed autophagosomes by influencing the biogenesis and protein interactions of Rab-interacting lysosomal protein (RILP), another dynein cargo adaptor. We tested effects of mTORC1 inhibition on interactions between the AP-2 and dynactin complexes, with a focus on their two essential subunits, AP-2β and p150Glued. We found that the mTORC1 inhibitor rapamycin enhanced p150Glued-AP-2β complex formation in both neurons and non-neuronal cells. Additional analysis revealed that the p150Glued-AP-2β interaction was indirect and required integrity of the dynactin complex. In non-neuronal cells rapamycin-driven enhancement of the p150Glued-AP-2β interaction also required the presence of cytoplasmic linker protein 170 (CLIP-170), the activation of autophagy, and an undisturbed endolysosomal system. The rapamycin-dependent p150Glued-AP-2β interaction occurred on lysosomal-associated membrane protein 1 (Lamp-1)-positive organelles but without the need for autolysosome formation. Rapamycin treatment also increased the acidification and number of acidic organelles and increased speed of the long-distance retrograde movement of Lamp-1-positive organelles. Altogether, our results indicate that autophagy regulates the p150Glued-AP-2β interaction, possibly to coordinate sufficient motor-adaptor complex availability for effective lysosome transport.
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Affiliation(s)
- Aleksandra Tempes
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology, Ks. Trojdena St. 4, 02-109, Warsaw, Poland
| | - Karolina Bogusz
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology, Ks. Trojdena St. 4, 02-109, Warsaw, Poland
| | - Agnieszka Brzozowska
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology, Ks. Trojdena St. 4, 02-109, Warsaw, Poland
| | - Jan Weslawski
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology, Ks. Trojdena St. 4, 02-109, Warsaw, Poland
| | - Matylda Macias
- Microscopy and Flow Cytometry Core Facility, International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Oliver Tkaczyk
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology, Ks. Trojdena St. 4, 02-109, Warsaw, Poland
| | - Katarzyna Orzoł
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology, Ks. Trojdena St. 4, 02-109, Warsaw, Poland
| | - Aleksandra Lew
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology, Ks. Trojdena St. 4, 02-109, Warsaw, Poland
| | | | - Tytus Bernas
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
- Microscopy Facility, Department of Anatomy and Neurology, Virginia Commonwealth University School of Medicine, Richmond, VA, USA
| | | | - Magdalena Mlostek
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology, Ks. Trojdena St. 4, 02-109, Warsaw, Poland
| | - Shiwani Kumari
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology, Ks. Trojdena St. 4, 02-109, Warsaw, Poland
| | - Ewa Liszewska
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology, Ks. Trojdena St. 4, 02-109, Warsaw, Poland
| | - Katarzyna Machnicka
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology, Ks. Trojdena St. 4, 02-109, Warsaw, Poland
| | - Magdalena Bakun
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Tymon Rubel
- Institute of Radioelectronics and Multimedia Technology, Warsaw University of Technology, Warsaw, Poland
| | - Anna R Malik
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology, Ks. Trojdena St. 4, 02-109, Warsaw, Poland.
- Cellular Neurobiology Research Group, Institute of Developmental Biology and Biomedical Sciences, Faculty of Biology, University of Warsaw, Miecznikowa St. 1, 02-096, Warsaw, Poland.
| | - Jacek Jaworski
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology, Ks. Trojdena St. 4, 02-109, Warsaw, Poland.
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Kashani E, Vassella E. Pleiotropy of PP2A Phosphatases in Cancer with a Focus on Glioblastoma IDH Wildtype. Cancers (Basel) 2022; 14:5227. [PMID: 36358647 PMCID: PMC9654311 DOI: 10.3390/cancers14215227] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 10/13/2022] [Accepted: 10/20/2022] [Indexed: 07/29/2023] Open
Abstract
Serine/Threonine protein phosphatase 2A (PP2A) is a heterotrimeric (or occasionally, heterodimeric) phosphatase with pleiotropic functions and ubiquitous expression. Despite the fact that they all contribute to protein dephosphorylation, multiple PP2A complexes exist which differ considerably by their subcellular localization and their substrate specificity, suggesting diverse PP2A functions. PP2A complex formation is tightly regulated by means of gene expression regulation by transcription factors, microRNAs, and post-translational modifications. Furthermore, a constant competition between PP2A regulatory subunits is taking place dynamically and depending on the spatiotemporal circumstance; many of the integral subunits can outcompete the rest, subjecting them to proteolysis. PP2A modulation is especially important in the context of brain tumors due to its ability to modulate distinct glioma-promoting signal transduction pathways, such as PI3K/Akt, Wnt, Ras, NF-κb, etc. Furthermore, PP2A is also implicated in DNA repair and survival pathways that are activated upon treatment of glioma cells with chemo-radiation. Depending on the cancer cell type, preclinical studies have shown some promise in utilising PP2A activator or PP2A inhibitors to overcome therapy resistance. This review has a special focus on "glioblastoma, IDH wild-type" (GBM) tumors, for which the therapy options have limited efficacy, and tumor relapse is inevitable.
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Affiliation(s)
- Elham Kashani
- Institute of Pathology, University of Bern, 3008 Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, 3012 Bern, Switzerland
| | - Erik Vassella
- Institute of Pathology, University of Bern, 3008 Bern, Switzerland
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3
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mTOR substrate phosphorylation in growth control. Cell 2022; 185:1814-1836. [PMID: 35580586 DOI: 10.1016/j.cell.2022.04.013] [Citation(s) in RCA: 132] [Impact Index Per Article: 66.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 04/05/2022] [Accepted: 04/07/2022] [Indexed: 12/20/2022]
Abstract
The target of rapamycin (TOR), discovered 30 years ago, is a highly conserved serine/threonine protein kinase that plays a central role in regulating cell growth and metabolism. It is activated by nutrients, growth factors, and cellular energy. TOR forms two structurally and functionally distinct complexes, TORC1 and TORC2. TOR signaling activates cell growth, defined as an increase in biomass, by stimulating anabolic metabolism while inhibiting catabolic processes. With emphasis on mammalian TOR (mTOR), we comprehensively reviewed the literature and identified all reported direct substrates. In the context of recent structural information, we discuss how mTORC1 and mTORC2, despite having a common catalytic subunit, phosphorylate distinct substrates. We conclude that the two complexes recruit different substrates to phosphorylate a common, minimal motif.
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Sewell AK, Poss ZC, Ebmeier CC, Jacobsen JR, Old WM, Han M. The TORC1 phosphoproteome in C. elegans reveals roles in transcription and autophagy. iScience 2022; 25:104186. [PMID: 35479415 PMCID: PMC9036118 DOI: 10.1016/j.isci.2022.104186] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 03/14/2022] [Accepted: 03/29/2022] [Indexed: 11/13/2022] Open
Abstract
The protein kinase complex target of rapamycin complex 1 (TORC1) is a critical mediator of nutrient sensing that has been widely studied in cultured cells and yeast, yet our understanding of the regulatory activities of TORC1 in the context of a whole, multi-cellular organism is still very limited. Using Caenorhabditis elegans, we analyzed the DAF-15/Raptor-dependent phosphoproteome by quantitative mass spectrometry and characterized direct kinase targets by in vitro kinase assays. Here, we show new targets of TORC1 that indicate previously unknown regulation of transcription and autophagy. Our results further show that DAF-15/Raptor is differentially expressed during postembryonic development, suggesting a dynamic role for TORC1 signaling throughout the life span. This study provides a comprehensive view of the TORC1 phosphoproteome, reveals more than 100 DAF-15/Raptor-dependent phosphosites that reflect the complex function of TORC1 in a whole, multi-cellular organism, and serves as a rich resource to the field.
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Affiliation(s)
- Aileen K. Sewell
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309-0347, USA
| | - Zachary C. Poss
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309-0347, USA
| | - Christopher C. Ebmeier
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309-0347, USA
| | - Jeremy R. Jacobsen
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309-0347, USA
| | - William M. Old
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309-0347, USA
| | - Min Han
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309-0347, USA
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Schwarz JJ, Grundmann L, Kokot T, Kläsener K, Fotteler S, Medgyesi D, Köhn M, Reth M, Warscheid B. Quantitative proteomics identifies PTP1B as modulator of B cell antigen receptor signaling. Life Sci Alliance 2021; 4:4/11/e202101084. [PMID: 34526379 PMCID: PMC8473724 DOI: 10.26508/lsa.202101084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 08/28/2021] [Accepted: 09/01/2021] [Indexed: 11/24/2022] Open
Abstract
This study analyses the function of the protein tyrosine phosphatase 1B identifying its binding partners and dephosphorylation targets for modulating B cell antigen receptor signaling. B cell antigen receptor (BCR) signaling is initiated by protein kinases and limited by counteracting phosphatases that currently are less well studied in their regulation of BCR signaling. Here, we used the B cell line Ramos to identify and quantify human B cell signaling components. Specifically, a protein tyrosine phosphatase profiling revealed a high expression of the protein tyrosine phosphatase 1B (PTP1B) in Ramos and human naïve B cells. The loss of PTP1B leads to increased B cell activation. Through substrate trapping in combination with quantitative mass spectrometry, we identified 22 putative substrates or interactors of PTP1B. We validated Igα, CD22, PLCγ1/2, CBL, BCAP, and APLP2 as specific substrates of PTP1B in Ramos B cells. The tyrosine kinase BTK and the two adaptor proteins GRB2 and VAV1 were identified as direct binding partners and potential substrates of PTP1B. We showed that PTP1B dephosphorylates the inhibitory receptor protein CD22 at phosphotyrosine 807. We conclude that PTP1B negatively modulates BCR signaling by dephosphorylating distinct phosphotyrosines in B cell-specific receptor proteins and various downstream signaling components.
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Affiliation(s)
- Jennifer J Schwarz
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany
| | - Lorenz Grundmann
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Thomas Kokot
- Integrative Signalling Research, Institute of Biology III, Faculty of Biology, University of Freiburg, Freiburg, Germany.,Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Kathrin Kläsener
- Department for Molecular Immunology, Institute of Biology III, Faculty of Biology, University of Freiburg, Freiburg, Germany.,Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Sandra Fotteler
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - David Medgyesi
- Department for Molecular Immunology, Institute of Biology III, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Maja Köhn
- Integrative Signalling Research, Institute of Biology III, Faculty of Biology, University of Freiburg, Freiburg, Germany.,Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany
| | - Michael Reth
- Department for Molecular Immunology, Institute of Biology III, Faculty of Biology, University of Freiburg, Freiburg, Germany.,Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany
| | - Bettina Warscheid
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, Germany .,Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany
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6
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Koscielny A, Liszewska E, Machnicka K, Wezyk M, Kotulska K, Jaworski J. mTOR controls endoplasmic reticulum-Golgi apparatus trafficking of VSVg in specific cell types. Cell Mol Biol Lett 2021; 26:18. [PMID: 34006213 PMCID: PMC8130434 DOI: 10.1186/s11658-021-00262-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 05/10/2021] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Mammalian/mechanistic target of rapamycin (mTOR) complexes are essential for cell proliferation, growth, differentiation, and survival. mTORC1 hyperactivation occurs in the tuberous sclerosis complex (TSC). mTORC1 localizes to the surface of lysosomes, where Rheb activates it. However, mTOR was also found on the endoplasmic reticulum (ER) and Golgi apparatus (GA). Recent studies showed that the same inputs regulate ER-to-GA cargo transport and mTORC1 (e.g., the level of amino acids or energy status of the cell). Nonetheless, it remains unknown whether mTOR contributes to the regulation of cargo passage through the secretory pathway. METHODS The retention using selective hooks (RUSH) approach was used to image movement of model cargo (VSVg) between the ER and GA in various cell lines in which mTOR complexes were inhibited. We also investigated VSVg trafficking in TSC patient fibroblasts. RESULTS We found that mTOR inhibition led to the overall enhancement of VSVg transport through the secretory pathway in PC12 cells and primary human fibroblasts. Also, in TSC1-deficient cells, VSVg transport was enhanced. CONCLUSIONS Altogether, these data indicate the involvement of mTOR in the regulation of ER-to-GA cargo transport and suggest that impairments in exocytosis may be an additional cellular process that is disturbed in TSC.
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Affiliation(s)
- Alicja Koscielny
- International Institute of Molecular and Cell Biology, 4 Ks. Trojdena St., 04-421, Warsaw, Poland
| | - Ewa Liszewska
- International Institute of Molecular and Cell Biology, 4 Ks. Trojdena St., 04-421, Warsaw, Poland
| | - Katarzyna Machnicka
- International Institute of Molecular and Cell Biology, 4 Ks. Trojdena St., 04-421, Warsaw, Poland
| | - Michalina Wezyk
- International Institute of Molecular and Cell Biology, 4 Ks. Trojdena St., 04-421, Warsaw, Poland.,Laboratory of Neurogenetics, Department of Neurodegenerative Disorders, Mossakowski Medical Research Centre of the Polish Academy of Sciences, 5 Pawinskiego St., 02-106, Warsaw, Poland
| | - Katarzyna Kotulska
- Department of Neurology and Epileptology, The Children's Memorial Health Institute, Aleja Dzieci Polskich 20, 04-730, Warsaw, Poland
| | - Jacek Jaworski
- International Institute of Molecular and Cell Biology, 4 Ks. Trojdena St., 04-421, Warsaw, Poland.
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7
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Prentzell MT, Rehbein U, Cadena Sandoval M, De Meulemeester AS, Baumeister R, Brohée L, Berdel B, Bockwoldt M, Carroll B, Chowdhury SR, von Deimling A, Demetriades C, Figlia G, de Araujo MEG, Heberle AM, Heiland I, Holzwarth B, Huber LA, Jaworski J, Kedra M, Kern K, Kopach A, Korolchuk VI, van 't Land-Kuper I, Macias M, Nellist M, Palm W, Pusch S, Ramos Pittol JM, Reil M, Reintjes A, Reuter F, Sampson JR, Scheldeman C, Siekierska A, Stefan E, Teleman AA, Thomas LE, Torres-Quesada O, Trump S, West HD, de Witte P, Woltering S, Yordanov TE, Zmorzynska J, Opitz CA, Thedieck K. G3BPs tether the TSC complex to lysosomes and suppress mTORC1 signaling. Cell 2021; 184:655-674.e27. [PMID: 33497611 PMCID: PMC7868890 DOI: 10.1016/j.cell.2020.12.024] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 11/03/2020] [Accepted: 12/14/2020] [Indexed: 12/22/2022]
Abstract
Ras GTPase-activating protein-binding proteins 1 and 2 (G3BP1 and G3BP2, respectively) are widely recognized as core components of stress granules (SGs). We report that G3BPs reside at the cytoplasmic surface of lysosomes. They act in a non-redundant manner to anchor the tuberous sclerosis complex (TSC) protein complex to lysosomes and suppress activation of the metabolic master regulator mechanistic target of rapamycin complex 1 (mTORC1) by amino acids and insulin. Like the TSC complex, G3BP1 deficiency elicits phenotypes related to mTORC1 hyperactivity. In the context of tumors, low G3BP1 levels enhance mTORC1-driven breast cancer cell motility and correlate with adverse outcomes in patients. Furthermore, G3bp1 inhibition in zebrafish disturbs neuronal development and function, leading to white matter heterotopia and neuronal hyperactivity. Thus, G3BPs are not only core components of SGs but also a key element of lysosomal TSC-mTORC1 signaling.
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Affiliation(s)
- Mirja Tamara Prentzell
- Brain Cancer Metabolism Group, German Consortium of Translational Cancer Research (DKTK) & German Cancer Research Center (DKFZ), Heidelberg 69120, Germany; Department of Pediatrics, Section Systems Medicine of Metabolism and Signaling, University of Groningen, University Medical Center Groningen, Groningen 9700 RB, The Netherlands; Department of Bioinformatics and Molecular Genetics (Faculty of Biology), University of Freiburg, Freiburg 79104, Germany; Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg 79104, Germany
| | - Ulrike Rehbein
- Department of Pediatrics, Section Systems Medicine of Metabolism and Signaling, University of Groningen, University Medical Center Groningen, Groningen 9700 RB, The Netherlands; Department for Neuroscience, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg 26129, Germany; Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck 6020, Austria
| | - Marti Cadena Sandoval
- Department of Pediatrics, Section Systems Medicine of Metabolism and Signaling, University of Groningen, University Medical Center Groningen, Groningen 9700 RB, The Netherlands; Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck 6020, Austria
| | - Ann-Sofie De Meulemeester
- Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences, University of Leuven, Leuven BE-3000, Belgium
| | - Ralf Baumeister
- Department of Bioinformatics and Molecular Genetics (Faculty of Biology), University of Freiburg, Freiburg 79104, Germany; Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg 79104, Germany; Signalling Research Centres BIOSS and CIBSS & ZBMZ Center for Biochemistry and Molecular Cell Research (Faculty of Medicine), University of Freiburg, Freiburg 79104, Germany
| | - Laura Brohée
- Cell Growth Control in Health and Age-Related Disease Group, Max Planck Institute for Biology of Ageing (MPI-AGE), Cologne 50931, Germany
| | - Bianca Berdel
- Brain Cancer Metabolism Group, German Consortium of Translational Cancer Research (DKTK) & German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Mathias Bockwoldt
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø 9037, Norway
| | - Bernadette Carroll
- School of Biochemistry, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Suvagata Roy Chowdhury
- Cell Signaling and Metabolism Group, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Andreas von Deimling
- German Consortium of Translational Cancer Research (DKTK), Clinical Cooperation Unit Neuropathology, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany; Department of Neuropathology, Institute of Pathology, Heidelberg University, Heidelberg 69120, Germany
| | - Constantinos Demetriades
- Cell Growth Control in Health and Age-Related Disease Group, Max Planck Institute for Biology of Ageing (MPI-AGE), Cologne 50931, Germany; CECAD Cluster of Excellence, University of Cologne, Cologne 50931, Germany
| | - Gianluca Figlia
- Signal Transduction in Cancer and Metabolism, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany; Heidelberg University, Heidelberg 69120, Germany
| | | | - Alexander M Heberle
- Department of Pediatrics, Section Systems Medicine of Metabolism and Signaling, University of Groningen, University Medical Center Groningen, Groningen 9700 RB, The Netherlands; Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck 6020, Austria
| | - Ines Heiland
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø 9037, Norway
| | - Birgit Holzwarth
- Department of Bioinformatics and Molecular Genetics (Faculty of Biology), University of Freiburg, Freiburg 79104, Germany
| | - Lukas A Huber
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, Innsbruck 6020, Austria; Austrian Drug Screening Institute (ADSI), Innsbruck 6020, Austria
| | - Jacek Jaworski
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology in Warsaw, Warsaw 02-109, Poland
| | - Magdalena Kedra
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology in Warsaw, Warsaw 02-109, Poland
| | - Katharina Kern
- Brain Cancer Metabolism Group, German Consortium of Translational Cancer Research (DKTK) & German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Andrii Kopach
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology in Warsaw, Warsaw 02-109, Poland
| | - Viktor I Korolchuk
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Ineke van 't Land-Kuper
- Department of Pediatrics, Section Systems Medicine of Metabolism and Signaling, University of Groningen, University Medical Center Groningen, Groningen 9700 RB, The Netherlands; Department for Neuroscience, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg 26129, Germany
| | - Matylda Macias
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology in Warsaw, Warsaw 02-109, Poland
| | - Mark Nellist
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam 3015 GD, The Netherlands
| | - Wilhelm Palm
- Cell Signaling and Metabolism Group, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Stefan Pusch
- German Consortium of Translational Cancer Research (DKTK), Clinical Cooperation Unit Neuropathology, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany; Department of Neuropathology, Institute of Pathology, Heidelberg University, Heidelberg 69120, Germany
| | - Jose Miguel Ramos Pittol
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck 6020, Austria
| | - Michèle Reil
- Brain Cancer Metabolism Group, German Consortium of Translational Cancer Research (DKTK) & German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Anja Reintjes
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck 6020, Austria
| | - Friederike Reuter
- Brain Cancer Metabolism Group, German Consortium of Translational Cancer Research (DKTK) & German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Julian R Sampson
- Institute of Medical Genetics, Division of Cancer and Genetics, Cardiff University Medical School, Cardiff CF14 4AY, UK
| | - Chloë Scheldeman
- Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences, University of Leuven, Leuven BE-3000, Belgium; Neurogenetics Research Group, VUB, Brussels 1090, Belgium
| | - Aleksandra Siekierska
- Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences, University of Leuven, Leuven BE-3000, Belgium
| | - Eduard Stefan
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck 6020, Austria
| | - Aurelio A Teleman
- Signal Transduction in Cancer and Metabolism, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany; Heidelberg University, Heidelberg 69120, Germany
| | - Laura E Thomas
- Institute of Life Science, Swansea University, Swansea SA2 8PP, UK
| | - Omar Torres-Quesada
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck 6020, Austria
| | - Saskia Trump
- Molecular Epidemiology Unit, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health (BIH), Berlin 13353, Germany
| | - Hannah D West
- Institute of Medical Genetics, Division of Cancer and Genetics, Cardiff University Medical School, Cardiff CF14 4AY, UK
| | - Peter de Witte
- Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences, University of Leuven, Leuven BE-3000, Belgium
| | - Sandra Woltering
- Brain Cancer Metabolism Group, German Consortium of Translational Cancer Research (DKTK) & German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Teodor E Yordanov
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, Innsbruck 6020, Austria; Division of Cell and Developmental Biology, Institute for Molecular Bioscience, University of Queensland, St Lucia QLD 4072, Australia
| | - Justyna Zmorzynska
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology in Warsaw, Warsaw 02-109, Poland
| | - Christiane A Opitz
- Brain Cancer Metabolism Group, German Consortium of Translational Cancer Research (DKTK) & German Cancer Research Center (DKFZ), Heidelberg 69120, Germany; Department of Neurology, University Hospital Heidelberg and National Center for Tumor Diseases, Heidelberg 69120, Germany.
| | - Kathrin Thedieck
- Department of Pediatrics, Section Systems Medicine of Metabolism and Signaling, University of Groningen, University Medical Center Groningen, Groningen 9700 RB, The Netherlands; Department for Neuroscience, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg 26129, Germany; Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck 6020, Austria.
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8
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Lin YC, Lu YH, Lee YC, Hung CS, Lin JC. Altered expressions and splicing profiles of Acin1 transcripts differentially modulate brown adipogenesis through an alternative splicing mechanism. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1863:194601. [PMID: 32629174 DOI: 10.1016/j.bbagrm.2020.194601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 06/26/2020] [Accepted: 06/28/2020] [Indexed: 10/23/2022]
Abstract
Apoptotic chromatin condensation inducer in the nucleus (also referred as Acin1) was first characterized as an RNA-binding protein involved in apoptosis. In later reports, Acin1 was identified as an auxiliary component of the exon junction complex (EJC) which is assembled throughout pre-messenger RNA splicing. In this study, results of whole-transcriptome analyses revealed reduced expressions and reprogrammed splicing profiles of Acin1 transcripts throughout development of brown adipose tissues (BATs) that execute non-shivering thermogenesis in small rodents and infants by consuming lipids. Depletion of endogenous Acin1 isoforms led to activation of brown adipogenic signatures in mouse C3H10T1/2 fibroblasts. Nevertheless, overexpressions of the Acin1-L or Acin1-S isoform exerted discriminative influences on brown adipogenesis and reprogramming of the expression of serine/arginine-rich splicing factor 3 (SRSF3) through an alternative splicing-coupled nonsense-mediated decay mechanism in a sequence-specific manner. Moreover, the Acin1-SRSF3 axis constitutes a regulatory pathway that participates in the brown adipocyte-related splicing network. Taken together, the interplay between accessory EJC components and splicing regulators constitutes an emerging mechanism for differentially manipulating the activity of brown adipogenesis via alternative splicing network.
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Affiliation(s)
- Ying-Chin Lin
- Department of Family Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Department of Family Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Yi-Han Lu
- School of Medical Laboratory Science and Biotechnology, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Yuan-Chii Lee
- Graduate Institute of Biomedical Informatics, Taipei Medical University, Taipei, Taiwan
| | - Ching-Sheng Hung
- PhD Program in Medical Biotechnology, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan; Department of Laboratory Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Jung-Chun Lin
- School of Medical Laboratory Science and Biotechnology, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan; PhD Program in Medical Biotechnology, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan; Pulmonary Research Center, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan.
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9
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Xue L, Xie L, Song X, Song X. [Expression and Significance of ACIN1 mRNA in Platelets of Lung Cancer]. ZHONGGUO FEI AI ZA ZHI = CHINESE JOURNAL OF LUNG CANCER 2018; 21:677-681. [PMID: 30201066 PMCID: PMC6137000 DOI: 10.3779/j.issn.1009-3419.2018.09.05] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
BACKGROUND During the occurring and developing of tumor, tumor-educated platelets mRNA profiles were altered. Since platelets are anuclear, the level of mRNAs is probably post-transcriptional regulated by the splicing maturation of pre-mRNA and alternative splicing. Apoptotic chromatin condensation inducer 1 (ACIN1) has been shown to be a component of a splicing-dependent multiprotein exon junction complex (EJC) and was involved in mRNA metabolism associated with splicing. This study analyzed the expression of ACIN1 mRNA in platelets, and explored its potential as a biomarker of lung cancer. METHODS 156 patients with lung cancer and 58 healthy controls in Shandong Cancer Hospital were collected. We isolated platelet pellets by low-speed centrifugation and extracted total RNA. The expression of ACIN1 mRNA in platelets was detected by RT-PCR, the results were analyzed statistically. And the relationship between expression of ACIN1 mRNA and clinical factors were also analyzed. RESULTS The expression level of ACIN1 mRNA in platelets of patients with lung cancer was significantly higher than that in platelets of healthy controls (P=0.015). The ROC curve showed that the area under the curve of ACIN1 mRNA for detecting lung cancer were 0.608. The expression of ACIN1 mRNA in platelets of lung cancer has no significant relationship with age, gender, pathological type and metastasis or not (P>0.05). CONCLUSIONS ACIN1 mRNA was highly expressed in platelets of lung cancer patients, and the detection of its expression level might have potential clinical value for the diagnosis of lung cancer.
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Affiliation(s)
- Linlin Xue
- Shandong Cancer Hospital Affiliated to Shandong University, Jinan 250117, China; Shandong Academy of Medical Sciences, Jinan 250002,China
| | - Li Xie
- Shandong Cancer Hospital Affiliated to Shandong University, Jinan 250117, China; Shandong Academy of Medical Sciences, Jinan 250002,China
| | - Xingguo Song
- Shandong Cancer Hospital Affiliated to Shandong University, Jinan 250117, China; Shandong Academy of Medical Sciences, Jinan 250002,China
| | - Xianrang Song
- Shandong Cancer Hospital Affiliated to Shandong University, Jinan 250117, China; Shandong Academy of Medical Sciences, Jinan 250002,China
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10
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Walters HE, Cox LS. mTORC Inhibitors as Broad-Spectrum Therapeutics for Age-Related Diseases. Int J Mol Sci 2018; 19:E2325. [PMID: 30096787 PMCID: PMC6121351 DOI: 10.3390/ijms19082325] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 07/22/2018] [Accepted: 07/30/2018] [Indexed: 02/06/2023] Open
Abstract
Chronological age represents the greatest risk factor for many life-threatening diseases, including neurodegeneration, cancer, and cardiovascular disease; ageing also increases susceptibility to infectious disease. Current efforts to tackle individual diseases may have little impact on the overall healthspan of older individuals, who would still be vulnerable to other age-related pathologies. However, recent progress in ageing research has highlighted the accumulation of senescent cells with chronological age as a probable underlying cause of pathological ageing. Cellular senescence is an essentially irreversible proliferation arrest mechanism that has important roles in development, wound healing, and preventing cancer, but it may limit tissue function and cause widespread inflammation with age. The serine/threonine kinase mTOR (mechanistic target of rapamycin) is a regulatory nexus that is heavily implicated in both ageing and senescence. Excitingly, a growing body of research has highlighted rapamycin and other mTOR inhibitors as promising treatments for a broad spectrum of age-related pathologies, including neurodegeneration, cancer, immunosenescence, osteoporosis, rheumatoid arthritis, age-related blindness, diabetic nephropathy, muscular dystrophy, and cardiovascular disease. In this review, we assess the use of mTOR inhibitors to treat age-related pathologies, discuss possible molecular mechanisms of action where evidence is available, and consider strategies to minimize undesirable side effects. We also emphasize the urgent need for reliable, non-invasive biomarkers of senescence and biological ageing to better monitor the efficacy of any healthy ageing therapy.
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Affiliation(s)
- Hannah E Walters
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
| | - Lynne S Cox
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
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11
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Zhang Y, Zhang Y, Yu Y. Global Phosphoproteomic Analysis of Insulin/Akt/mTORC1/S6K Signaling in Rat Hepatocytes. J Proteome Res 2017; 16:2825-2835. [PMID: 28689409 DOI: 10.1021/acs.jproteome.7b00140] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Insulin resistance is a hallmark of type 2 diabetes. Although multiple genetic and physiological factors interact to cause insulin resistance, deregulated signaling by phosphorylation is a common underlying mechanism. In particular, the specific phosphorylation-dependent regulatory mechanisms and signaling outputs of insulin are poorly understood in hepatocytes, which represents one of the most important insulin-responsive cell types. Using primary rat hepatocytes as a model system, we performed reductive dimethylation (ReDi)-based quantitative mass spectrometric analysis and characterized the phosphoproteome that is regulated by insulin as well as its key downstream kinases including Akt, mTORC1, and S6K. We identified a total of 12 294 unique, confidently localized phosphorylation sites and 3805 phosphorylated proteins in this single cell type. Detailed bioinformatic analysis on each individual data set identified both known and previously unrecognized targets of this key insulin downstream effector pathway. Furthermore, integrated analysis of the hepatic Akt/mTORC1/S6K signaling axis allowed the delineation of the substrate specificity of several close-related kinases within the insulin signaling pathway. We expect that the data sets will serve as an invaluable resource, providing the foundation for future hypothesis-driven research that helps delineate the molecular mechanisms that underlie the pathogenesis of type 2 diabetes and related metabolic syndrome.
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Affiliation(s)
- Yuanyuan Zhang
- Department of Molecular Genetics, University of Texas Southwestern Medical Center , Dallas, Texas 75390, United States
| | - Yajie Zhang
- Department of Biochemistry, University of Texas Southwestern Medical Center , Dallas, Texas 75390, United States
| | - Yonghao Yu
- Department of Biochemistry, University of Texas Southwestern Medical Center , Dallas, Texas 75390, United States
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12
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Ruf S, Heberle AM, Langelaar-Makkinje M, Gelino S, Wilkinson D, Gerbeth C, Schwarz JJ, Holzwarth B, Warscheid B, Meisinger C, van Vugt MATM, Baumeister R, Hansen M, Thedieck K. PLK1 (polo like kinase 1) inhibits MTOR complex 1 and promotes autophagy. Autophagy 2017; 13:486-505. [PMID: 28102733 PMCID: PMC5361591 DOI: 10.1080/15548627.2016.1263781] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 11/09/2016] [Accepted: 11/16/2016] [Indexed: 02/08/2023] Open
Abstract
Mechanistic target of rapamycin complex 1 (MTORC1) and polo like kinase 1 (PLK1) are major drivers of cancer cell growth and proliferation, and inhibitors of both protein kinases are currently being investigated in clinical studies. To date, MTORC1's and PLK1's functions are mostly studied separately, and reports on their mutual crosstalk are scarce. Here, we identify PLK1 as a physical MTORC1 interactor in human cancer cells. PLK1 inhibition enhances MTORC1 activity under nutrient sufficiency and in starved cells, and PLK1 directly phosphorylates the MTORC1 component RPTOR/RAPTOR in vitro. PLK1 and MTORC1 reside together at lysosomes, the subcellular site where MTORC1 is active. Consistent with an inhibitory role of PLK1 toward MTORC1, PLK1 overexpression inhibits lysosomal association of the PLK1-MTORC1 complex, whereas PLK1 inhibition promotes lysosomal localization of MTOR. PLK1-MTORC1 binding is enhanced by amino acid starvation, a condition known to increase autophagy. MTORC1 inhibition is an important step in autophagy activation. Consistently, PLK1 inhibition mitigates autophagy in cancer cells both under nutrient starvation and sufficiency, and a role of PLK1 in autophagy is also observed in the invertebrate model organism Caenorhabditis elegans. In summary, PLK1 inhibits MTORC1 and thereby positively contributes to autophagy. Since autophagy is increasingly recognized to contribute to tumor cell survival and growth, we propose that cautious monitoring of MTORC1 and autophagy readouts in clinical trials with PLK1 inhibitors is needed to develop strategies for optimized (combinatorial) cancer therapies targeting MTORC1, PLK1, and autophagy.
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Affiliation(s)
- Stefanie Ruf
- Department of Bioinformatics and Molecular Genetics, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Department of Pediatrics, Center for Liver, Digestive and Metabolic Diseases, University of Groningen, University Medical Center Groningen, AV Groningen, The Netherlands
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
- Research Training Group (RTG) 1104, University of Freiburg, Freiburg, Germany
| | - Alexander Martin Heberle
- Department of Pediatrics, Center for Liver, Digestive and Metabolic Diseases, University of Groningen, University Medical Center Groningen, AV Groningen, The Netherlands
| | - Miriam Langelaar-Makkinje
- Department of Pediatrics, Center for Liver, Digestive and Metabolic Diseases, University of Groningen, University Medical Center Groningen, AV Groningen, The Netherlands
| | - Sara Gelino
- Program of Development, Aging and Regeneration, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
- Graduate School of Biomedical Sciences, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Deepti Wilkinson
- Program of Development, Aging and Regeneration, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Carolin Gerbeth
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
- ZBMZ Centre for Biochemistry and Molecular Cell Research (Faculty of Medicine), University of Freiburg, Freiburg, Germany
- Institute of Biochemistry and Molecular Biology (Faculty of Medicine), University of Freiburg, Freiburg, Germany
| | - Jennifer Jasmin Schwarz
- Department of Biochemistry and Functional Proteomics, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany
| | - Birgit Holzwarth
- Department of Bioinformatics and Molecular Genetics, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Bettina Warscheid
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
- Department of Biochemistry and Functional Proteomics, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany
| | - Chris Meisinger
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
- ZBMZ Centre for Biochemistry and Molecular Cell Research (Faculty of Medicine), University of Freiburg, Freiburg, Germany
- Institute of Biochemistry and Molecular Biology (Faculty of Medicine), University of Freiburg, Freiburg, Germany
| | - Marcel A. T. M. van Vugt
- Department of Medical Oncology, Cancer Research Center Groningen, University of Groningen, University Medical Center Groningen, GZ Groningen, The Netherlands
| | - Ralf Baumeister
- Department of Bioinformatics and Molecular Genetics, Faculty of Biology, University of Freiburg, Freiburg, Germany
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
- Research Training Group (RTG) 1104, University of Freiburg, Freiburg, Germany
- ZBMZ Centre for Biochemistry and Molecular Cell Research (Faculty of Medicine), University of Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany
| | - Malene Hansen
- Program of Development, Aging and Regeneration, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Kathrin Thedieck
- Department of Pediatrics, Center for Liver, Digestive and Metabolic Diseases, University of Groningen, University Medical Center Groningen, AV Groningen, The Netherlands
- Department for Neuroscience, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
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13
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A systems study reveals concurrent activation of AMPK and mTOR by amino acids. Nat Commun 2016; 7:13254. [PMID: 27869123 PMCID: PMC5121333 DOI: 10.1038/ncomms13254] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 09/13/2016] [Indexed: 12/17/2022] Open
Abstract
Amino acids (aa) are not only building blocks for proteins, but also signalling molecules, with the mammalian target of rapamycin complex 1 (mTORC1) acting as a key mediator. However, little is known about whether aa, independently of mTORC1, activate other kinases of the mTOR signalling network. To delineate aa-stimulated mTOR network dynamics, we here combine a computational–experimental approach with text mining-enhanced quantitative proteomics. We report that AMP-activated protein kinase (AMPK), phosphatidylinositide 3-kinase (PI3K) and mTOR complex 2 (mTORC2) are acutely activated by aa-readdition in an mTORC1-independent manner. AMPK activation by aa is mediated by Ca2+/calmodulin-dependent protein kinase kinase β (CaMKKβ). In response, AMPK impinges on the autophagy regulators Unc-51-like kinase-1 (ULK1) and c-Jun. AMPK is widely recognized as an mTORC1 antagonist that is activated by starvation. We find that aa acutely activate AMPK concurrently with mTOR. We show that AMPK under aa sufficiency acts to sustain autophagy. This may be required to maintain protein homoeostasis and deliver metabolite intermediates for biosynthetic processes. mTORC1 is known to mediate the signalling activity of amino acids. Here, the authors combine modelling with experiments and find that amino acids acutely stimulate mTORC2, IRS/PI3K and AMPK, independently of mTORC1. AMPK activation through CaMKKβ sustains autophagy under non-starvation conditions.
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14
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Richter-Dennerlein R, Oeljeklaus S, Lorenzi I, Ronsör C, Bareth B, Schendzielorz AB, Wang C, Warscheid B, Rehling P, Dennerlein S. Mitochondrial Protein Synthesis Adapts to Influx of Nuclear-Encoded Protein. Cell 2016; 167:471-483.e10. [PMID: 27693358 PMCID: PMC5055049 DOI: 10.1016/j.cell.2016.09.003] [Citation(s) in RCA: 136] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 08/01/2016] [Accepted: 08/30/2016] [Indexed: 12/11/2022]
Abstract
Mitochondrial ribosomes translate membrane integral core subunits of the oxidative phosphorylation system encoded by mtDNA. These translation products associate with nuclear-encoded, imported proteins to form enzyme complexes that produce ATP. Here, we show that human mitochondrial ribosomes display translational plasticity to cope with the supply of imported nuclear-encoded subunits. Ribosomes expressing mitochondrial-encoded COX1 mRNA selectively engage with cytochrome c oxidase assembly factors in the inner membrane. Assembly defects of the cytochrome c oxidase arrest mitochondrial translation in a ribosome nascent chain complex with a partially membrane-inserted COX1 translation product. This complex represents a primed state of the translation product that can be retrieved for assembly. These findings establish a mammalian translational plasticity pathway in mitochondria that enables adaptation of mitochondrial protein synthesis to the influx of nuclear-encoded subunits. Mitochondrial ribosomes display translational plasticity COX1 translation in mitochondria is stalled in the absence of nuclear-encoded COX4 A ribosome nascent chain complex of COX1 is a primed state for complex IV assembly MITRAC regulates translation via COX1 ribosome nascent chain complexes interaction
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Affiliation(s)
- Ricarda Richter-Dennerlein
- Department of Cellular Biochemistry, University Medical Centre Göttingen, GZMB, 37073 Göttingen, Germany
| | - Silke Oeljeklaus
- Department of Biochemistry and Functional Proteomics, Faculty of Biology, University Freiburg, 79104 Freiburg, Germany
| | - Isotta Lorenzi
- Department of Cellular Biochemistry, University Medical Centre Göttingen, GZMB, 37073 Göttingen, Germany
| | - Christin Ronsör
- Department of Cellular Biochemistry, University Medical Centre Göttingen, GZMB, 37073 Göttingen, Germany
| | - Bettina Bareth
- Department of Cellular Biochemistry, University Medical Centre Göttingen, GZMB, 37073 Göttingen, Germany
| | | | - Cong Wang
- Department of Cellular Biochemistry, University Medical Centre Göttingen, GZMB, 37073 Göttingen, Germany
| | - Bettina Warscheid
- Department of Biochemistry and Functional Proteomics, Faculty of Biology, University Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Peter Rehling
- Department of Cellular Biochemistry, University Medical Centre Göttingen, GZMB, 37073 Göttingen, Germany; Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany.
| | - Sven Dennerlein
- Department of Cellular Biochemistry, University Medical Centre Göttingen, GZMB, 37073 Göttingen, Germany
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