1
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Wu G, Baumeister R, Heimbucher T. SGK-1 mediated inhibition of iron import is a determinant of lifespan in C. elegans. MicroPubl Biol 2023; 2023:10.17912/micropub.biology.000970. [PMID: 37799207 PMCID: PMC10550382 DOI: 10.17912/micropub.biology.000970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 09/13/2023] [Accepted: 09/14/2023] [Indexed: 10/07/2023]
Abstract
Maintaining iron levels is crucial for health, but iron overload has been associated with tumorigenesis. Therefore, critical enzymes involved in iron homeostasis are under tight, typically posttranslational control. In C. elegans , the mTORC2 and insulin/IGF-1 activated kinase SGK-1 is induced upon exogenous iron overload to couple iron storage and fat accumulation. Here we show that, already at physiological iron conditions, sgk-1 loss-of-function increases intracellular iron levels that may impair lifespan. Reducing iron levels by diminishing cellular or mitochondrial iron import is sufficient to extend the short lifespan of sgk-1 loss-of-function animals. Our results indicate another regulatory level of sgk-1 in iron homeostasis via negative feedback regulation on iron transporters.
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Affiliation(s)
- Gang Wu
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, 79104 Freiburg, Germany
- Bioinformatics and Molecular Genetics, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Ralf Baumeister
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, 79104 Freiburg, Germany
- Bioinformatics and Molecular Genetics, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
- Center for Biochemistry and Molecular Cell Research, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
- Faculty of Medicine, ZBMZ Center of Biochemistry and Molecular Cell Research, University of Freiburg, 79104 Freiburg, Germany
- FRIAS Freiburg Institute for Advanced Studies, Albertstraße 19, University of Freiburg, 79104 Freiburg, Germany
| | - Thomas Heimbucher
- Bioinformatics and Molecular Genetics, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
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2
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Xu F, Li R, von Gromoff ED, Drepper F, Knapp B, Warscheid B, Baumeister R, Qi W. Reprogramming of the transcriptome after heat stress mediates heat hormesis in Caenorhabditis elegans. Nat Commun 2023; 14:4176. [PMID: 37443152 PMCID: PMC10345090 DOI: 10.1038/s41467-023-39882-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 07/03/2023] [Indexed: 07/15/2023] Open
Abstract
Transient stress experiences not only trigger acute stress responses, but can also have long-lasting effects on cellular functions. In Caenorhabditis elegans, a brief exposure to heat shock during early adulthood extends lifespan and improves stress resistance, a phenomenon known as heat hormesis. Here, we investigated the prolonged effect of hormetic heat stress on the transcriptome of worms and found that the canonical heat shock response is followed by a profound transcriptional reprogramming in the post-stress period. This reprogramming relies on the endoribonuclease ENDU-2 but not the heat shock factor 1. ENDU-2 co-localizes with chromatin and interacts with RNA polymerase II, enabling specific regulation of transcription after the stress period. Failure to activate the post-stress response does not affect the resistance of animals to heat shock but eliminates the beneficial effects of hormetic heat stress. In summary, our work discovers that the RNA-binding protein ENDU-2 mediates the long-term impacts of transient heat stress via reprogramming transcriptome after stress exposure.
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Affiliation(s)
- Fan Xu
- Bioinformatics and Molecular Genetics (Faculty of Biology), Albert-Ludwigs-University Freiburg, Freiburg, 79104, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), Albert-Ludwigs-University Freiburg, Freiburg, 79104, Germany
| | - Ruoyao Li
- Bioinformatics and Molecular Genetics (Faculty of Biology), Albert-Ludwigs-University Freiburg, Freiburg, 79104, Germany
| | - Erika D von Gromoff
- Bioinformatics and Molecular Genetics (Faculty of Biology), Albert-Ludwigs-University Freiburg, Freiburg, 79104, Germany
| | - Friedel Drepper
- Biochemistry-Functional Proteomics, Institute of Biology II, Faculty of Biology, Albert-Ludwigs-University Freiburg, Freiburg, 79104, Germany
| | - Bettina Knapp
- Biochemistry-Functional Proteomics, Institute of Biology II, Faculty of Biology, Albert-Ludwigs-University Freiburg, Freiburg, 79104, Germany
| | - Bettina Warscheid
- Biochemistry-Functional Proteomics, Institute of Biology II, Faculty of Biology, Albert-Ludwigs-University Freiburg, Freiburg, 79104, Germany
- Signalling Research Centers BIOSS and CIBSS, Albert-Ludwigs-University Freiburg, Freiburg, 79104, Germany
- Biochemistry II, Theodor Boveri-Institute, Biocenter, University of Würzburg, 97074, Würzburg, Germany
| | - Ralf Baumeister
- Bioinformatics and Molecular Genetics (Faculty of Biology), Albert-Ludwigs-University Freiburg, Freiburg, 79104, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), Albert-Ludwigs-University Freiburg, Freiburg, 79104, Germany
- Signalling Research Centers BIOSS and CIBSS, Albert-Ludwigs-University Freiburg, Freiburg, 79104, Germany
- Center for Biochemistry and Molecular Cell Research (Faculty of Medicine), Albert-Ludwigs-University Freiburg, Freiburg, 79104, Germany
| | - Wenjing Qi
- Bioinformatics and Molecular Genetics (Faculty of Biology), Albert-Ludwigs-University Freiburg, Freiburg, 79104, Germany.
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3
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Wu G, Baumeister R, Heimbucher T. Molecular Mechanisms of Lipid-Based Metabolic Adaptation Strategies in Response to Cold. Cells 2023; 12:1353. [PMID: 37408188 PMCID: PMC10216534 DOI: 10.3390/cells12101353] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 04/24/2023] [Accepted: 05/05/2023] [Indexed: 07/07/2023] Open
Abstract
Temperature changes and periods of detrimental cold occur frequently for many organisms in their natural habitats. Homeothermic animals have evolved metabolic adaptation strategies to increase mitochondrial-based energy expenditure and heat production, largely relying on fat as a fuel source. Alternatively, certain species are able to repress their metabolism during cold periods and enter a state of decreased physiological activity known as torpor. By contrast, poikilotherms, which are unable to maintain their internal temperature, predominantly increase membrane fluidity to diminish cold-related damage from low-temperature stress. However, alterations of molecular pathways and the regulation of lipid-metabolic reprogramming during cold exposure are poorly understood. Here, we review organismal responses that adjust fat metabolism during detrimental cold stress. Cold-related changes in membranes are detected by membrane-bound sensors, which signal to downstream transcriptional effectors, including nuclear hormone receptors of the PPAR (peroxisome proliferator-activated receptor) subfamily. PPARs control lipid metabolic processes, such as fatty acid desaturation, lipid catabolism and mitochondrial-based thermogenesis. Elucidating the underlying molecular mechanisms of cold adaptation may improve beneficial therapeutic cold treatments and could have important implications for medical applications of hypothermia in humans. This includes treatment strategies for hemorrhagic shock, stroke, obesity and cancer.
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Affiliation(s)
- Gang Wu
- Bioinformatics and Molecular Genetics, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Ralf Baumeister
- Bioinformatics and Molecular Genetics, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
- Center for Biochemistry and Molecular Cell Research, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, 79104 Freiburg, Germany
| | - Thomas Heimbucher
- Bioinformatics and Molecular Genetics, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
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4
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Qi W, Xu F, Heimbucher T, Baumeister R. Protection of germline immortality by the soma via a secreted endoribonuclease. Bioessays 2021; 43:e2100195. [PMID: 34655094 DOI: 10.1002/bies.202100195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 09/24/2021] [Accepted: 09/28/2021] [Indexed: 11/08/2022]
Abstract
In sexually reproducing organisms maintenance of germ stem cell immortality is fundamental for transmitting genetic material to future generations. While previous research has mainly considered intrinsic regulatory mechanisms in the germline, our recent study has found a direct contribution of somatic cells in preserving germline immortality via the somatically expressed endoribonuclease ENDU-2 in Caenorhabditis elegans. We have identified ENDU-2 as a secreted protein that can be taken up by the germline. Here, we discuss how ENDU-2 might uncouple its RNA-binding and RNA-cleavage activities to control gene expression via either an endoribonuclease dependent or an independent way. We also speculate on a possible functional conservation of its mammalian homologs in mediating cell-cell communication as well as its potential significance in understanding human pathogenesis such as cancer development.
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Affiliation(s)
- Wenjing Qi
- Bioinformatics and Molecular Genetics (Faculty of Biology), Albert-Ludwigs-University Freiburg, Germany
| | - Fan Xu
- Bioinformatics and Molecular Genetics (Faculty of Biology), Albert-Ludwigs-University Freiburg, Germany.,Spemann Graduate School of Biology and Medicine (SGBM), Albert-Ludwigs-University Freiburg, Germany
| | - Thomas Heimbucher
- Bioinformatics and Molecular Genetics (Faculty of Biology), Albert-Ludwigs-University Freiburg, Germany
| | - Ralf Baumeister
- Bioinformatics and Molecular Genetics (Faculty of Biology), Albert-Ludwigs-University Freiburg, Germany.,Center for Biochemistry and Molecular Cell Research (Faculty of Medicine), Albert-Ludwigs-University Freiburg, Germany.,Signalling Research Centers BIOSS and CIBSS, Albert-Ludwigs-University Freiburg, Germany
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5
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Kienle K, Glaser KM, Eickhoff S, Mihlan M, Knöpper K, Reátegui E, Epple MW, Gunzer M, Baumeister R, Tarrant TK, Germain RN, Irimia D, Kastenmüller W, Lämmermann T. Neutrophils self-limit swarming to contain bacterial growth in vivo. Science 2021; 372:372/6548/eabe7729. [PMID: 34140358 DOI: 10.1126/science.abe7729] [Citation(s) in RCA: 70] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Accepted: 04/29/2021] [Indexed: 12/30/2022]
Abstract
Neutrophils communicate with each other to form swarms in infected organs. Coordination of this population response is critical for the elimination of bacteria and fungi. Using transgenic mice, we found that neutrophils have evolved an intrinsic mechanism to self-limit swarming and avoid uncontrolled aggregation during inflammation. G protein-coupled receptor (GPCR) desensitization acts as a negative feedback control to stop migration of neutrophils when they sense high concentrations of self-secreted attractants that initially amplify swarming. Interference with this process allows neutrophils to scan larger tissue areas for microbes. Unexpectedly, this does not benefit bacterial clearance as containment of proliferating bacteria by neutrophil clusters becomes impeded. Our data reveal how autosignaling stops self-organized swarming behavior and how the finely tuned balance of neutrophil chemotaxis and arrest counteracts bacterial escape.
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Affiliation(s)
- Korbinian Kienle
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany.,International Max Planck Research School for Immunobiology, Epigenetics and Metabolism (IMPRS-IEM), Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Katharina M Glaser
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany.,International Max Planck Research School for Immunobiology, Epigenetics and Metabolism (IMPRS-IEM), Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Sarah Eickhoff
- Institute of Systems Immunology, University of Würzburg, Max Planck Research Group, Würzburg, Germany
| | - Michael Mihlan
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Konrad Knöpper
- Institute of Systems Immunology, University of Würzburg, Max Planck Research Group, Würzburg, Germany
| | - Eduardo Reátegui
- Center for Engineering in Medicine, Massachusetts General Hospital, Harvard Medical School, Shriners Hospital for Children, Boston, MA, USA.,William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH, USA
| | - Maximilian W Epple
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany.,International Max Planck Research School for Immunobiology, Epigenetics and Metabolism (IMPRS-IEM), Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Matthias Gunzer
- Institute for Experimental Immunology and Imaging, University Hospital, University Duisburg-Essen, Essen, Germany.,Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., Dortmund, Germany
| | - Ralf Baumeister
- Bioinformatics and Molecular Genetics, Faculty of Biology, Centre for Biochemistry and Molecular Cell Research, Faculty of Medicine, Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Teresa K Tarrant
- Division of Rheumatology and Immunology, Department of Medicine, Duke University School of Medicine, Durham, NC, USA
| | - Ronald N Germain
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA
| | - Daniel Irimia
- Center for Engineering in Medicine, Massachusetts General Hospital, Harvard Medical School, Shriners Hospital for Children, Boston, MA, USA
| | - Wolfgang Kastenmüller
- Institute of Systems Immunology, University of Würzburg, Max Planck Research Group, Würzburg, Germany
| | - Tim Lämmermann
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany.
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6
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Qi W, Gromoff EDV, Xu F, Zhao Q, Yang W, Pfeifer D, Maier W, Long L, Baumeister R. Author Correction: The secreted endoribonuclease ENDU-2 from the soma protects germline immortality in C. elegans. Nat Commun 2021; 12:3315. [PMID: 34050169 PMCID: PMC8163770 DOI: 10.1038/s41467-021-23820-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Affiliation(s)
- Wenjing Qi
- Bioinformatics and Molecular Genetics (Faculty of Biology), Albert-Ludwigs-University Freiburg, Freiburg, Germany.
| | - Erika D V Gromoff
- Bioinformatics and Molecular Genetics (Faculty of Biology), Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Fan Xu
- Bioinformatics and Molecular Genetics (Faculty of Biology), Albert-Ludwigs-University Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine (SGBM), Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Qian Zhao
- Bioinformatics and Molecular Genetics (Faculty of Biology), Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Wei Yang
- Bioinformatics and Molecular Genetics (Faculty of Biology), Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Dietmar Pfeifer
- Department of Hematology, Oncology and Stem Cell Transplantation, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Wolfgang Maier
- Bioinformatics and Molecular Genetics (Faculty of Biology), Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Lijiang Long
- Bioinformatics and Molecular Genetics (Faculty of Biology), Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Ralf Baumeister
- Bioinformatics and Molecular Genetics (Faculty of Biology), Albert-Ludwigs-University Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine (SGBM), Albert-Ludwigs-University Freiburg, Freiburg, Germany.,Center for Biochemistry and Molecular Cell Research (ZBMZ, Faculty of Medicine), Albert-Ludwigs-University Freiburg, Freiburg, Germany.,Signalling Research Centers BIOSS and CIBSS, Albert-Ludwigs-University Freiburg, Freiburg, Germany
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7
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Baumeister R, Murphy CT, Heimbucher T. Metabolic adaptation to hypoxia: do worms and cancer cells share common metabolic responses to hypoxic stress? Cell Death Differ 2021; 28:1434-1436. [PMID: 33580155 PMCID: PMC8026991 DOI: 10.1038/s41418-021-00741-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 01/20/2021] [Accepted: 01/21/2021] [Indexed: 01/28/2023] Open
Affiliation(s)
- Ralf Baumeister
- Bioinformatics and Molecular Genetics, Institute of Biology 3, Faculty of Biology, University of Freiburg, Freiburg, Baden-Wuerttemberg, Germany. .,Center for Biochemistry and Molecular Cell Research (ZBMZ), Faculty of Medicine, University of Freiburg, Freiburg, Baden-Wuerttemberg, Germany. .,Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Baden-Wuerttemberg, Germany.
| | - Coleen T Murphy
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA.,Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Thomas Heimbucher
- Bioinformatics and Molecular Genetics, Institute of Biology 3, Faculty of Biology, University of Freiburg, Freiburg, Baden-Wuerttemberg, Germany.
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8
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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: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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9
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Abstract
Macroautophagy/autophagy is an evolutionarily conserved cellular degradation and recycling process that is tightly regulated by external stimuli, diet, and stress. Our recent findings suggest that in C. elegans, a nutrient sensing pathway mediated by MTORC2 (mechanistic target of rapamycin kinase complex 2) and its downstream effector kinase SGK-1 (serum- and glucocorticoid-inducible kinase homolog 1) suppresses autophagy, involving mitophagy. Induced autophagy/mitophagy in MTORC2-deficient animals slows down development and impairs reproduction independently of the SGK-1 effectors DAF-16/FOXO and SKN-1/NFE2L2/NRF2. In this punctum, we discuss how TORC2-SGK-1 signaling might regulate autophagic turnover and its impact on mitochondrial homeostasis via linking mitochondria-derived reactive oxygen species (mtROS) production to mitophagic turnover.
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Affiliation(s)
- Thomas Heimbucher
- Bioinformatics and Molecular Genetics, Faculty of Biology, University of Freiburg , Freiburg, Germany
| | - Wenjing Qi
- Bioinformatics and Molecular Genetics, Faculty of Biology, University of Freiburg , Freiburg, Germany.,Signalling Research Centres BIOSS and CIBSS, University of Freiburg , Freiburg, Germany
| | - Ralf Baumeister
- Bioinformatics and Molecular Genetics, Faculty of Biology, University of Freiburg , Freiburg, Germany.,Signalling Research Centres BIOSS and CIBSS, University of Freiburg , Freiburg, Germany.,Center for Biochemistry and Molecular Cell Research, Faculty of Medicine, University of Freiburg , Freiburg, Germany
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10
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Karabinos A, Schulze E, Baumeister R. Analysis of the novel excretory cell expressed ECP-1 protein and its proposed ECP-1/IFC-2 fusion protein EXC-2 in the nematode Caenorhabditis elegans. Gene Expr Patterns 2019; 34:119061. [DOI: 10.1016/j.gep.2019.119061] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Revised: 05/15/2019] [Accepted: 06/11/2019] [Indexed: 02/07/2023]
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11
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Kvainickas A, Nägele H, Qi W, Dokládal L, Jimenez-Orgaz A, Stehl L, Gangurde D, Zhao Q, Hu Z, Dengjel J, De Virgilio C, Baumeister R, Steinberg F. Retromer and TBC1D5 maintain late endosomal RAB7 domains to enable amino acid-induced mTORC1 signaling. J Cell Biol 2019; 218:3019-3038. [PMID: 31431476 PMCID: PMC6719456 DOI: 10.1083/jcb.201812110] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 05/30/2019] [Accepted: 07/08/2019] [Indexed: 02/07/2023] Open
Abstract
Retromer is an evolutionarily conserved multiprotein complex that orchestrates the endocytic recycling of integral membrane proteins. Here, we demonstrate that retromer is also required to maintain lysosomal amino acid signaling through mTORC1 across species. Without retromer, amino acids no longer stimulate mTORC1 translocation to the lysosomal membrane, which leads to a loss of mTORC1 activity and increased induction of autophagy. Mechanistically, we show that its effect on mTORC1 activity is not linked to retromer's role in the recycling of transmembrane proteins. Instead, retromer cooperates with the RAB7-GAP TBC1D5 to restrict late endosomal RAB7 into microdomains that are spatially separated from the amino acid-sensing domains. Upon loss of retromer, RAB7 expands into the ragulator-decorated amino acid-sensing domains and interferes with RAG-GTPase and mTORC1 recruitment. Depletion of retromer in Caenorhabditis elegans reduces mTORC1 signaling and extends the lifespan of the worms, confirming an evolutionarily conserved and unexpected role for retromer in the regulation of mTORC1 activity and longevity.
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Affiliation(s)
- Arunas Kvainickas
- Center for Biological Systems Analysis, University of Freiburg, Freiburg, Germany
| | - Heike Nägele
- Center for Biological Systems Analysis, University of Freiburg, Freiburg, Germany
| | - Wenjing Qi
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Ladislav Dokládal
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Ana Jimenez-Orgaz
- Center for Biological Systems Analysis, University of Freiburg, Freiburg, Germany
| | - Luca Stehl
- Center for Biological Systems Analysis, University of Freiburg, Freiburg, Germany
| | - Dipak Gangurde
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Qian Zhao
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Zehan Hu
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Jörn Dengjel
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | | | - Ralf Baumeister
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Florian Steinberg
- Center for Biological Systems Analysis, University of Freiburg, Freiburg, Germany
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12
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Jiang YY, Maier W, Baumeister R, Minevich G, Joachimiak E, Wloga D, Ruan Z, Kannan N, Bocarro S, Bahraini A, Vasudevan KK, Lechtreck K, Orias E, Gaertig J. LF4/MOK and a CDK-related kinase regulate the number and length of cilia in Tetrahymena. PLoS Genet 2019; 15:e1008099. [PMID: 31339880 PMCID: PMC6682161 DOI: 10.1371/journal.pgen.1008099] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 08/05/2019] [Accepted: 06/13/2019] [Indexed: 11/18/2022] Open
Abstract
The length of cilia is controlled by a poorly understood mechanism that involves members of the conserved RCK kinase group, and among them, the LF4/MOK kinases. The multiciliated protist model, Tetrahymena, carries two types of cilia (oral and locomotory) and the length of the locomotory cilia is dependent on their position with the cell. In Tetrahymena, loss of an LF4/MOK ortholog, LF4A, lengthened the locomotory cilia, but also reduced their number. Without LF4A, cilia assembled faster and showed signs of increased intraflagellar transport (IFT). Consistently, overproduced LF4A shortened cilia and downregulated IFT. GFP-tagged LF4A, expressed in the native locus and imaged by total internal reflection microscopy, was enriched at the basal bodies and distributed along the shafts of cilia. Within cilia, most LF4A-GFP particles were immobile and a few either diffused or moved by IFT. We suggest that the distribution of LF4/MOK along the cilium delivers a uniform dose of inhibition to IFT trains that travel from the base to the tip. In a longer cilium, the IFT machinery may experience a higher cumulative dose of inhibition by LF4/MOK. Thus, LF4/MOK activity could be a readout of cilium length that helps to balance the rate of IFT-driven assembly with the rate of disassembly at steady state. We used a forward genetic screen to identify a CDK-related kinase, CDKR1, whose loss-of-function suppressed the shortening of cilia caused by overexpression of LF4A, by reducing its kinase activity. Loss of CDKR1 alone lengthened both the locomotory and oral cilia. CDKR1 resembles other known ciliary CDK-related kinases: LF2 of Chlamydomonas, mammalian CCRK and DYF-18 of C. elegans, in lacking the cyclin-binding motif and acting upstream of RCKs. The new genetic tools we developed here for Tetrahymena have potential for further dissection of the principles of cilia length regulation in multiciliated cells.
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Affiliation(s)
- Yu-Yang Jiang
- Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Wolfgang Maier
- Bio 3/Bioinformatics and Molecular Genetics, Faculty of Biology and ZBMZ, Faculty of Medicine, Albert-Ludwigs-University of Freiburg, Freiburg, Germany
| | - Ralf Baumeister
- Bio 3/Bioinformatics and Molecular Genetics, Faculty of Biology and ZBMZ, Faculty of Medicine, Albert-Ludwigs-University of Freiburg, Freiburg, Germany
| | - Gregory Minevich
- Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center, New York, New York, United States of America
| | - Ewa Joachimiak
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Dorota Wloga
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Zheng Ruan
- Institute of Bioinformatics, University of Georgia, Athens, Georgia, United States of America
| | - Natarajan Kannan
- Institute of Bioinformatics, University of Georgia, Athens, Georgia, United States of America
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Stephen Bocarro
- Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Anoosh Bahraini
- Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Krishna Kumar Vasudevan
- Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Karl Lechtreck
- Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Eduardo Orias
- Department of Molecular, Cellular and Developmental Biology, University of California Santa Barbara, Santa Barbara, California, United States of America
| | - Jacek Gaertig
- Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
- * E-mail:
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13
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Hernando-Rodríguez B, Erinjeri AP, Rodríguez-Palero MJ, Millar V, González-Hernández S, Olmedo M, Schulze B, Baumeister R, Muñoz MJ, Askjaer P, Artal-Sanz M. Combined flow cytometry and high-throughput image analysis for the study of essential genes in Caenorhabditis elegans. BMC Biol 2018; 16:36. [PMID: 29598825 PMCID: PMC5875015 DOI: 10.1186/s12915-018-0496-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 02/06/2018] [Indexed: 12/28/2022] Open
Abstract
Background Advances in automated image-based microscopy platforms coupled with high-throughput liquid workflows have facilitated the design of large-scale screens utilising multicellular model organisms such as Caenorhabditis elegans to identify genetic interactions, therapeutic drugs or disease modifiers. However, the analysis of essential genes has lagged behind because lethal or sterile mutations pose a bottleneck for high-throughput approaches, and a systematic way to analyse genetic interactions of essential genes in multicellular organisms has been lacking. Results In C. elegans, non-conditional lethal mutations can be maintained in heterozygosity using chromosome balancers, commonly expressing green fluorescent protein (GFP) in the pharynx. However, gene expression or function is typically monitored by the use of fluorescent reporters marked with the same fluorophore, presenting a challenge to sort worm populations of interest, particularly at early larval stages. Here, we develop a sorting strategy capable of selecting homozygous mutants carrying a GFP stress reporter from GFP-balanced animals at the second larval stage. Because sorting is not completely error-free, we develop an automated high-throughput image analysis protocol that identifies and discards animals carrying the chromosome balancer. We demonstrate the experimental usefulness of combining sorting of homozygous lethal mutants and automated image analysis in a functional genomic RNA interference (RNAi) screen for genes that genetically interact with mitochondrial prohibitin (PHB). Lack of PHB results in embryonic lethality, while homozygous PHB deletion mutants develop into sterile adults due to maternal contribution and strongly induce the mitochondrial unfolded protein response (UPRmt). In a chromosome-wide RNAi screen for C. elegans genes having human orthologues, we uncover both known and new PHB genetic interactors affecting the UPRmt and growth. Conclusions The method presented here allows the study of balanced lethal mutations in a high-throughput manner. It can be easily adapted depending on the user’s requirements and should serve as a useful resource for the C. elegans community for probing new biological aspects of essential nematode genes as well as the generation of more comprehensive genetic networks. Electronic supplementary material The online version of this article (10.1186/s12915-018-0496-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Blanca Hernando-Rodríguez
- Andalusian Center for Developmental Biology, Consejo Superior de Investigaciones Científicas/Junta de Andalucía/Universidad Pablo de Olavide, Seville, Spain.,Department of Molecular Biology and Biochemical Engineering, Universidad Pablo de Olavide, Seville, Spain
| | - Annmary Paul Erinjeri
- Andalusian Center for Developmental Biology, Consejo Superior de Investigaciones Científicas/Junta de Andalucía/Universidad Pablo de Olavide, Seville, Spain.,Department of Molecular Biology and Biochemical Engineering, Universidad Pablo de Olavide, Seville, Spain
| | - María Jesús Rodríguez-Palero
- Andalusian Center for Developmental Biology, Consejo Superior de Investigaciones Científicas/Junta de Andalucía/Universidad Pablo de Olavide, Seville, Spain.,Department of Molecular Biology and Biochemical Engineering, Universidad Pablo de Olavide, Seville, Spain
| | - Val Millar
- GE Healthcare Life Sciences, Maynard Centre, Forest Farm, Whitchurch, Cardiff, UK.,Present address: Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Sara González-Hernández
- Andalusian Center for Developmental Biology, Consejo Superior de Investigaciones Científicas/Junta de Andalucía/Universidad Pablo de Olavide, Seville, Spain.,Department of Molecular Biology and Biochemical Engineering, Universidad Pablo de Olavide, Seville, Spain.,Present address: Cell and Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain
| | - María Olmedo
- Andalusian Center for Developmental Biology, Consejo Superior de Investigaciones Científicas/Junta de Andalucía/Universidad Pablo de Olavide, Seville, Spain.,Department of Molecular Biology and Biochemical Engineering, Universidad Pablo de Olavide, Seville, Spain.,Present address: Department of Genetics, University of Seville, Seville, Spain
| | - Bettina Schulze
- Centre for Biological Signalling Studies (BIOSS), Laboratory for Bioinformatics and Molecular Genetics, Faculty of Biology, and ZBMZ Center for Biochemistry and Molecular Cell Biology (Faculty of Medicine), Albert-Ludwigs-University of Freiburg, Freiburg, Germany
| | - Ralf Baumeister
- Centre for Biological Signalling Studies (BIOSS), Laboratory for Bioinformatics and Molecular Genetics, Faculty of Biology, and ZBMZ Center for Biochemistry and Molecular Cell Biology (Faculty of Medicine), Albert-Ludwigs-University of Freiburg, Freiburg, Germany
| | - Manuel J Muñoz
- Andalusian Center for Developmental Biology, Consejo Superior de Investigaciones Científicas/Junta de Andalucía/Universidad Pablo de Olavide, Seville, Spain.,Department of Molecular Biology and Biochemical Engineering, Universidad Pablo de Olavide, Seville, Spain
| | - Peter Askjaer
- Andalusian Center for Developmental Biology, Consejo Superior de Investigaciones Científicas/Junta de Andalucía/Universidad Pablo de Olavide, Seville, Spain
| | - Marta Artal-Sanz
- Andalusian Center for Developmental Biology, Consejo Superior de Investigaciones Científicas/Junta de Andalucía/Universidad Pablo de Olavide, Seville, Spain. .,Department of Molecular Biology and Biochemical Engineering, Universidad Pablo de Olavide, Seville, Spain.
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14
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Li Y, Finkbeiner S, Ganner A, Gerber J, Klein M, Grafe M, Kandzia J, Thien A, Thedieck K, Breves G, Jank T, Baumeister R, Walz G, Neumann-Haefelin E. CGEF-1 regulates mTORC1 signaling during adult longevity and stress response in C. elegans. Oncotarget 2018. [PMID: 29515755 PMCID: PMC5839386 DOI: 10.18632/oncotarget.24039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The mechanistic target of rapamycin (mTOR) kinase is central to metabolism and growth, and has a conserved role in aging. mTOR functions in two complexes, mTORC1 and mTORC2. In diverse eukaryotes, inhibition of mTORC1 signaling increases lifespan. mTORC1 transduces anabolic signals to stimulate protein synthesis and inhibits autophagy. In this study, we demonstrate that CGEF-1, the C. elegans homolog of the human guanine nucleotide exchange factor Dbl, is a novel binding partner of RHEB-1 and activator of mTORC1 signaling in C. elegans. cgef-1 mutants display prolonged lifespan and enhanced stress resistance. The transcription factors DAF-16/FoxO and SKN-1/Nrf are required for increased longevity and stress tolerance, and induce protective gene expression in cgef-1 mutants. Genetic evidence indicates that cgef-1 functions in the same pathway with rheb-1, the mTOR kinase let-363, and daf-15/Raptor. When cgef-1 is inactivated, phosphorylation of 4E-BP, a central mTORC1 substrate for protein translation is reduced in C. elegans. Moreover, autophagy is increased upon cgef-1 and mTORC1 inhibition. In addition, we show that in human cells Dbl associates with Rheb and stimulates mTORC1 downstream targets for protein synthesis suggesting that the function of CGEF-1/Dbl in the mTORC1 signaling pathway is evolutionarily conserved. These findings have important implications for mTOR functions and signaling mechanisms in aging and age-related diseases.
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Affiliation(s)
- Yujie Li
- Department of Nephrology, Medical Center, University of Freiburg, Freiburg, Germany
| | - Sandra Finkbeiner
- Department of Nephrology, Medical Center, University of Freiburg, Freiburg, Germany
| | - Athina Ganner
- Department of Nephrology, Medical Center, University of Freiburg, Freiburg, Germany
| | - Julia Gerber
- Department of Nephrology, Medical Center, University of Freiburg, Freiburg, Germany.,Department of Physiology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Marinella Klein
- Department of Nephrology, Medical Center, University of Freiburg, Freiburg, Germany
| | - Manuel Grafe
- Department of Nephrology, Medical Center, University of Freiburg, Freiburg, Germany
| | - Jakob Kandzia
- Department of Nephrology, Medical Center, University of Freiburg, Freiburg, Germany
| | - Antje Thien
- Department of Nephrology, Medical Center, University of Freiburg, Freiburg, Germany.,Bioinformatics and Molecular Genetics, Faculty of Biology, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Kathrin Thedieck
- Bioinformatics and Molecular Genetics, Faculty of Biology, Albert-Ludwigs-University Freiburg, Freiburg, Germany.,Department of Pediatrics, Section Systems Medicine of Metabolism and Signaling, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.,Department for Neuroscience, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Gerhard Breves
- Department of Physiology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Thomas Jank
- Institute for Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, Albert-Ludwigs-University of Freiburg, Freiburg, Germany
| | - Ralf Baumeister
- Bioinformatics and Molecular Genetics, Faculty of Biology, Albert-Ludwigs-University Freiburg, Freiburg, Germany.,Centre for Biological Signaling Studies (BIOSS), Albert-Ludwigs-University of Freiburg, Freiburg, Germany.,Centre for Biological Systems Analysis (ZBSA), Albert-Ludwigs-University Freiburg, Freiburg, Germany.,ZBMZ Centre for Biochemistry and Molecular Cell Research, Faculty of Medicine, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Gerd Walz
- Department of Nephrology, Medical Center, University of Freiburg, Freiburg, Germany.,Centre for Biological Signaling Studies (BIOSS), Albert-Ludwigs-University of Freiburg, Freiburg, Germany
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15
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Eisenhardt AE, Sprenger A, Röring M, Herr R, Weinberg F, Köhler M, Braun S, Orth J, Diedrich B, Lanner U, Tscherwinski N, Schuster S, Dumaz N, Schmidt E, Baumeister R, Schlosser A, Dengjel J, Brummer T. Phospho-proteomic analyses of B-Raf protein complexes reveal new regulatory principles. Oncotarget 2018; 7:26628-52. [PMID: 27034005 PMCID: PMC5042004 DOI: 10.18632/oncotarget.8427] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 03/07/2016] [Indexed: 12/19/2022] Open
Abstract
B-Raf represents a critical physiological regulator of the Ras/RAF/MEK/ERK-pathway and a pharmacological target of growing clinical relevance, in particular in oncology. To understand how B-Raf itself is regulated, we combined mass spectrometry with genetic approaches to map its interactome in MCF-10A cells as well as in B-Raf deficient murine embryonic fibroblasts (MEFs) and B-Raf/Raf-1 double deficient DT40 lymphoma cells complemented with wildtype or mutant B-Raf expression vectors. Using a multi-protease digestion approach, we identified a novel ubiquitination site and provide a detailed B-Raf phospho-map. Importantly, we identify two evolutionary conserved phosphorylation clusters around T401 and S419 in the B-Raf hinge region. SILAC labelling and genetic/biochemical follow-up revealed that these clusters are phosphorylated in the contexts of oncogenic Ras, sorafenib induced Raf dimerization and in the background of the V600E mutation. We further show that the vemurafenib sensitive phosphorylation of the T401 cluster occurs in trans within a Raf dimer. Substitution of the Ser/Thr-residues of this cluster by alanine residues enhances the transforming potential of B-Raf, indicating that these phosphorylation sites suppress its signaling output. Moreover, several B-Raf phosphorylation sites, including T401 and S419, are somatically mutated in tumors, further illustrating the importance of phosphorylation for the regulation of this kinase.
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Affiliation(s)
- Anja E Eisenhardt
- Institute of Molecular Medicine and Cell Research (IMMZ), Faculty of Medicine, Albert-Ludwigs-University (ALU), Freiburg, Germany.,Institute of Biology III, Faculty of Biology, ALU, Freiburg, Germany.,Centre for Biological Systems Analysis (ZBSA), Freiburg, Germany
| | - Adrian Sprenger
- Centre for Biological Systems Analysis (ZBSA), Freiburg, Germany.,Institute for Experimental and Clinical Pharmacology and Toxicology, ALU, Freiburg, Germany.,INSERM U976 and Universitéi Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Michael Röring
- Institute of Molecular Medicine and Cell Research (IMMZ), Faculty of Medicine, Albert-Ludwigs-University (ALU), Freiburg, Germany.,Institute of Biology III, Faculty of Biology, ALU, Freiburg, Germany.,Centre for Biological Systems Analysis (ZBSA), Freiburg, Germany.,Spemann Graduate School of Biology and Medicine (SGBM), ALU, Freiburg, Germany
| | - Ricarda Herr
- Institute of Molecular Medicine and Cell Research (IMMZ), Faculty of Medicine, Albert-Ludwigs-University (ALU), Freiburg, Germany.,Institute of Biology III, Faculty of Biology, ALU, Freiburg, Germany.,Centre for Biological Systems Analysis (ZBSA), Freiburg, Germany
| | - Florian Weinberg
- Institute of Molecular Medicine and Cell Research (IMMZ), Faculty of Medicine, Albert-Ludwigs-University (ALU), Freiburg, Germany.,Institute of Biology III, Faculty of Biology, ALU, Freiburg, Germany.,Centre for Biological Systems Analysis (ZBSA), Freiburg, Germany
| | - Martin Köhler
- Institute of Molecular Medicine and Cell Research (IMMZ), Faculty of Medicine, Albert-Ludwigs-University (ALU), Freiburg, Germany.,Institute of Biology III, Faculty of Biology, ALU, Freiburg, Germany.,Centre for Biological Systems Analysis (ZBSA), Freiburg, Germany.,Spemann Graduate School of Biology and Medicine (SGBM), ALU, Freiburg, Germany
| | - Sandra Braun
- Institute of Molecular Medicine and Cell Research (IMMZ), Faculty of Medicine, Albert-Ludwigs-University (ALU), Freiburg, Germany.,Institute of Biology III, Faculty of Biology, ALU, Freiburg, Germany.,Centre for Biological Systems Analysis (ZBSA), Freiburg, Germany
| | - Joachim Orth
- Institute for Experimental and Clinical Pharmacology and Toxicology, ALU, Freiburg, Germany
| | - Britta Diedrich
- Centre for Biological Systems Analysis (ZBSA), Freiburg, Germany.,Department of Dermatology, University Medical Centre, ALU, Freiburg, Germany
| | - Ulrike Lanner
- Centre for Biological Systems Analysis (ZBSA), Freiburg, Germany
| | - Natalja Tscherwinski
- Institute of Biology III, Faculty of Biology, ALU, Freiburg, Germany.,Centre for Biological Systems Analysis (ZBSA), Freiburg, Germany
| | - Simon Schuster
- Institute of Biology III, Faculty of Biology, ALU, Freiburg, Germany.,Centre for Biological Systems Analysis (ZBSA), Freiburg, Germany
| | - Nicolas Dumaz
- INSERM U976 and Universitéi Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Enrico Schmidt
- Institute of Biology III, Faculty of Biology, ALU, Freiburg, Germany.,Centre for Biological Systems Analysis (ZBSA), Freiburg, Germany
| | - Ralf Baumeister
- Institute of Biology III, Faculty of Biology, ALU, Freiburg, Germany.,Centre for Biological Systems Analysis (ZBSA), Freiburg, Germany.,Freiburg Institute for Advanced Studies (FRIAS), ALU, Freiburg, Germany.,Centre for Biological Signalling Studies BIOSS, ALU, Freiburg, Germany
| | - Andreas Schlosser
- Institute of Biology III, Faculty of Biology, ALU, Freiburg, Germany.,Centre for Biological Systems Analysis (ZBSA), Freiburg, Germany.,Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - Jörn Dengjel
- Centre for Biological Systems Analysis (ZBSA), Freiburg, Germany.,Department of Dermatology, University Medical Centre, ALU, Freiburg, Germany.,Freiburg Institute for Advanced Studies (FRIAS), ALU, Freiburg, Germany.,Centre for Biological Signalling Studies BIOSS, ALU, Freiburg, Germany.,Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Tilman Brummer
- Institute of Molecular Medicine and Cell Research (IMMZ), Faculty of Medicine, Albert-Ludwigs-University (ALU), Freiburg, Germany.,Institute of Biology III, Faculty of Biology, ALU, Freiburg, Germany.,Centre for Biological Systems Analysis (ZBSA), Freiburg, Germany.,Centre for Biological Signalling Studies BIOSS, ALU, Freiburg, Germany.,German Cancer Consortium (DKTK), Freiburg, Germany
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16
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Jiang YY, Maier W, Baumeister R, Minevich G, Joachimiak E, Ruan Z, Kannan N, Clarke D, Frankel J, Gaertig J. The Hippo Pathway Maintains the Equatorial Division Plane in the Ciliate Tetrahymena. Genetics 2017; 206:873-888. [PMID: 28413159 PMCID: PMC5499192 DOI: 10.1534/genetics.117.200766] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 03/29/2017] [Indexed: 12/30/2022] Open
Abstract
The mechanisms that govern pattern formation within the cell are poorly understood. Ciliates carry on their surface an elaborate pattern of cortical organelles that are arranged along the anteroposterior and circumferential axes by largely unknown mechanisms. Ciliates divide by tandem duplication: the cortex of the predivision cell is remodeled into two similarly sized and complete daughters. In the conditional cdaI-1 mutant of Tetrahymena thermophila, the division plane migrates from its initially correct equatorial position toward the cell's anterior, resulting in unequal cell division, and defects in nuclear divisions and cytokinesis. We used comparative whole genome sequencing to identify the cause of cdaI-1 as a mutation in a Hippo/Mst kinase. CdaI is a cortical protein with a cell cycle-dependent, highly polarized localization. Early in cell division, CdaI marks the anterior half of the cell, and later concentrates at the posterior end of the emerging anterior daughter. Despite the strong association of CdaI with the new posterior cell end, the cdaI-1 mutation does not affect the patterning of the new posterior cortical organelles. We conclude that, in Tetrahymena, the Hippo pathway maintains an equatorial position of the fission zone, and, by this activity, specifies the relative dimensions of the anterior and posterior daughter cell.
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Affiliation(s)
- Yu-Yang Jiang
- Department of Cellular Biology, University of Georgia, Athens, Georgia 30602
| | - Wolfgang Maier
- Bio3/Bioinformatics and Molecular Genetics (Faculty of Biology) and ZMBZ (Faculty of Medicine)
| | - Ralf Baumeister
- Bio3/Bioinformatics and Molecular Genetics (Faculty of Biology) and ZMBZ (Faculty of Medicine)
- Centre for Biological Signalling Studies (BIOSS), Albert-Ludwigs-University of Freiburg, 79104 Germany
| | - Gregory Minevich
- Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center, New York, New York 10032
| | - Ewa Joachimiak
- Laboratory of Cytoskeleton and Cilia Biology, Department of Cell Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 02-093 Warsaw, Poland
| | - Zheng Ruan
- Institute of Bioinformatics, University of Georgia, Athens, Georgia 30602
| | - Natarajan Kannan
- Institute of Bioinformatics, University of Georgia, Athens, Georgia 30602
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602
| | - Diamond Clarke
- Department of Cellular Biology, University of Georgia, Athens, Georgia 30602
| | - Joseph Frankel
- Department of Biology, University of Iowa, Iowa City, Iowa 52242
| | - Jacek Gaertig
- Department of Cellular Biology, University of Georgia, Athens, Georgia 30602
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17
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Qi W, Yan Y, Pfeifer D, Donner v. Gromoff E, Wang Y, Maier W, Baumeister R. C. elegans DAF-16/FOXO interacts with TGF-ß/BMP signaling to induce germline tumor formation via mTORC1 activation. PLoS Genet 2017; 13:e1006801. [PMID: 28549065 PMCID: PMC5467913 DOI: 10.1371/journal.pgen.1006801] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 06/12/2017] [Accepted: 05/05/2017] [Indexed: 11/18/2022] Open
Abstract
Activation of the FOXO transcription factor DAF-16 by reduced insulin/IGF signaling (IIS) is considered to be beneficial in C. elegans due to its ability to extend lifespan and to enhance stress resistance. In the germline, cell-autonomous DAF-16 activity prevents stem cell proliferation, thus acting tumor-suppressive. In contrast, hypodermal DAF-16 causes a tumorous germline phenotype characterized by hyperproliferation of the germline stem cells and rupture of the adjacent basement membrane. Here we show that cross-talk between DAF-16 and the transforming growth factor ß (TGFß)/bone morphogenic protein (BMP) signaling pathway causes germline hyperplasia and results in disruption of the basement membrane. In addition to activating MADM/NRBP/hpo-11 gene alone, DAF-16 also directly interacts with both R-SMAD proteins SMA-2 and SMA-3 in the nucleus to regulate the expression of mTORC1 pathway. Knocking-down of BMP genes or each of the four target genes in the hypodermis was sufficient to inhibit germline proliferation, indicating a cell-non-autonomously controlled regulation of stem cell proliferation by somatic tissues. We propose the existence of two antagonistic DAF-16/FOXO functions, a cell-proliferative somatic and an anti-proliferative germline activity. Whereas germline hyperplasia under reduced IIS is inhibited by DAF-16 cell-autonomously, activation of somatic DAF-16 in the presence of active IIS promotes germline proliferation and eventually induces tumor-like germline growth. In summary, our results suggest a novel pathway crosstalk of DAF-16 and TGF-ß/BMP that can modulate mTORC1 at the transcriptional level to cause stem-cell hyperproliferation. Such cell-type specific differences may help explaining why human FOXO activity is considered to be tumor-suppressive in most contexts, but may become oncogenic, e.g. in chronic and acute myeloid leukemia. The transcription factor FOXO is a well-known tumor suppressor whose activity is controlled by nutrients and stress signaling. In the roundworm C. elegans, the activity of the FOXO protein DAF-16 is best known for its beneficial role in stress response and long lifespan. However, FOXO proteins may also promote tumor cell growth and maintenance in chronic and acute myeloid leukemia, suggesting that may have different roles in distinct contexts. Previously we have shown that selective activation of DAF-16 in the epidermis causes a tumorous growth in the stem cells of the C. elegans germline. Now we demonstrate that this oncogenic activity of DAF-16 is mediated by interactions with the transforming growth factor (TGFß)/Bone Morphogenic protein (BMP) signaling pathway. In the epidermis, direct binding of DAF-16 and R-SMAD proteins of the BMP pathway helps to activate genes involved in the mTORC1 signaling pathway that is frequently activated in tumors. We propose that the transcription factor DAF-16/FOXO may be controlled in different ways in the stem cells, in which its activity normally prevents tumor formation, and in other tissues, in which defects in controlling its activity may result in overwriting the beneficial stem cell activity to eventually promote tumor cell growth.
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Affiliation(s)
- Wenjing Qi
- Bioinformatics and Molecular Genetics, Faculty of Biology, University of Freiburg, Freiburg, Baden-Wuerttemberg, Germany
| | - Yijian Yan
- Bioinformatics and Molecular Genetics, Faculty of Biology, University of Freiburg, Freiburg, Baden-Wuerttemberg, Germany
| | - Dietmar Pfeifer
- Department of Internal Medicine, University Medical Center Freiburg, Freiburg, Baden-Wuerttemberg, Germany
| | - Erika Donner v. Gromoff
- Bioinformatics and Molecular Genetics, Faculty of Biology, University of Freiburg, Freiburg, Baden-Wuerttemberg, Germany
| | - Yimin Wang
- Bioinformatics and Molecular Genetics, Faculty of Biology, University of Freiburg, Freiburg, Baden-Wuerttemberg, Germany
| | - Wolfgang Maier
- Bioinformatics and Molecular Genetics, Faculty of Biology, University of Freiburg, Freiburg, Baden-Wuerttemberg, Germany
| | - Ralf Baumeister
- Bioinformatics and Molecular Genetics, Faculty of Biology, University of Freiburg, Freiburg, Baden-Wuerttemberg, Germany
- Center for Biochemistry and Molecular Cell Research, Faculty of Medicine, University of Freiburg, Freiburg, Baden-Wuerttemberg, Germany
- Centre for Biological Signaling Studies (BIOSS), University of Freiburg, Freiburg, Baden-Wuerttemberg, Germany
- * E-mail:
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18
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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19
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Runkel ED, Liu S, Baumeister R, Schulze E. Correction: Surveillance-Activated Defenses Block the ROS-Induced Mitochondrial Unfolded Protein Response. PLoS Genet 2016; 12:e1006377. [PMID: 27716778 PMCID: PMC5065125 DOI: 10.1371/journal.pgen.1006377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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20
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Weiss M, Schwarz F, Wallmichrath J, Baumeister R, Frick A, Bartenstein P, Rominger A. Chylothorax and chylous ascites. Clinical utility of planar scintigraphy and tomographic imaging with SPECT/CT. Nuklearmedizin 2015; 54:231-40. [PMID: 26183818 DOI: 10.3413/nukmed-0723-15-02] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 07/09/2015] [Indexed: 11/20/2022]
Abstract
UNLABELLED The aim was to analyze conventional planar scintigraphy and SPECT/CT in patients clinically suspicious for chylothorax or chylous ascites. Lymphoscintigraphy was performed for two reasons: first, to help diagnose chylothorax or -abdomen, by demonstrating diffuse uptake in fluid accumulations, and then secondly, to detect the site of leakage to test the prediction that additional use of SPECT/CT-technique improves upon the diagnostic value of planar lymphoscintigraphy in the baseline detection of thoraco-abdominal lymphatic disorders. PATIENTS, MATERIAL, METHODS From 7/2008-7/2014 a total of 24 consecutive patients (8 woman, 16 men; age, range 31-79 years) presenting with clinical symptoms suspicious for chylothorax and/or chylous ascites were examined by planar lymphoscintigraphy (n = 26) and additional tomographic SPECT/CT- (n = 22) or SPECT-technique (n = 2). RESULTS Chylothorax could be scintigraphically confirmed in n = 9, chylous ascites in n = 5 scintigraphies, and excluded in n = 10 patients. In all planar scintigraphy findings of pathological lymph drainage regions (n = 14), SPECT/CT delivered additional relevant information, notably the anatomic localization of the lymphatic leakage. For the baseline detection of thoraco-abdominal lymphatic transport disorders, lymphoscintigraphy showed sensitivity of 88%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 80%. CONCLUSIONS Our findings show that due to the particular advantages presented by tomographic separation of overlapping sources, SPECT/CT specifies better the anatomical sites, improving the localization of lymphatic leakage in aid of planning surgical re-interventions.
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Affiliation(s)
- M Weiss
- Mayo Weiss MD, Department of Nuclear Medicine, Ludwig-Maximilians-University of Munich, Marchioninistr.15, 81377 Muenchen, Germany, Tel. +49/(0)89/440 07 76 38, E-mail:
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21
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Thien A, Prentzell M, Holzwarth B, Kläsener K, Kuper I, Boehlke C, Sonntag A, Ruf S, Maerz L, Nitschke R, Grellscheid SN, Reth M, Walz G, Baumeister R, Neumann-Haefelin E, Thedieck K. TSC1 Activates TGF-β-Smad2/3 Signaling in Growth Arrest and Epithelial-to-Mesenchymal Transition. Dev Cell 2015. [DOI: 10.1016/j.devcel.2015.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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22
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Thien A, Prentzell MT, Holzwarth B, Kläsener K, Kuper I, Boehlke C, Sonntag AG, Ruf S, Maerz L, Nitschke R, Grellscheid SN, Reth M, Walz G, Baumeister R, Neumann-Haefelin E, Thedieck K. TSC1 activates TGF-β-Smad2/3 signaling in growth arrest and epithelial-to-mesenchymal transition. Dev Cell 2015; 32:617-30. [PMID: 25727005 DOI: 10.1016/j.devcel.2015.01.026] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Revised: 12/19/2014] [Accepted: 01/22/2015] [Indexed: 11/27/2022]
Abstract
The tuberous sclerosis proteins TSC1 and TSC2 are key integrators of growth factor signaling. They suppress cell growth and proliferation by acting in a heteromeric complex to inhibit the mammalian target of rapamycin complex 1 (mTORC1). In this study, we identify TSC1 as a component of the transforming growth factor β (TGF-β)-Smad2/3 pathway. Here, TSC1 functions independently of TSC2. TSC1 interacts with the TGF-β receptor complex and Smad2/3 and is required for their association with one another. TSC1 regulates TGF-β-induced Smad2/3 phosphorylation and target gene expression and controls TGF-β-induced growth arrest and epithelial-to-mesenchymal transition (EMT). Hyperactive Akt specifically activates TSC1-dependent cytostatic Smad signaling to induce growth arrest. Thus, TSC1 couples Akt activity to TGF-β-Smad2/3 signaling. This has implications for cancer treatments targeting phosphoinositide 3-kinases and Akt because they may impair tumor-suppressive cytostatic TGF-β signaling by inhibiting Akt- and TSC1-dependent Smad activation.
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Affiliation(s)
- Antje Thien
- Bioinformatics and Molecular Genetics (Faculty of Biology), Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Renal Division, University Hospital Freiburg, 79106 Freiburg, Germany
| | - Mirja Tamara Prentzell
- Bioinformatics and Molecular Genetics (Faculty of Biology), Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Spemann Graduate School of Biology and Medicine (SGBM), Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Department of Pediatrics, Center for Liver, Digestive and Metabolic Diseases, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, the Netherlands
| | - Birgit Holzwarth
- Bioinformatics and Molecular Genetics (Faculty of Biology), Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Kathrin Kläsener
- Molecular Immunology (Faculty of Biology), Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Molecular Immunology, Max-Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany; BIOSS Centre for Biological Signaling Studies, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Ineke Kuper
- Department of Pediatrics, Center for Liver, Digestive and Metabolic Diseases, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, the Netherlands; Department for Neuroscience, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, 26129 Oldenburg, Germany
| | | | - Annika G Sonntag
- Bioinformatics and Molecular Genetics (Faculty of Biology), Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Stefanie Ruf
- Bioinformatics and Molecular Genetics (Faculty of Biology), Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Department of Pediatrics, Center for Liver, Digestive and Metabolic Diseases, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, the Netherlands; BIOSS Centre for Biological Signaling Studies, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Research Training Group (RTG) 1104, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Lars Maerz
- Bioinformatics and Molecular Genetics (Faculty of Biology), Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Roland Nitschke
- BIOSS Centre for Biological Signaling Studies, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Center for Biological Systems Analysis (ZBSA), Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | | | - Michael Reth
- Spemann Graduate School of Biology and Medicine (SGBM), Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Molecular Immunology (Faculty of Biology), Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Molecular Immunology, Max-Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany; BIOSS Centre for Biological Signaling Studies, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Gerd Walz
- Renal Division, University Hospital Freiburg, 79106 Freiburg, Germany; BIOSS Centre for Biological Signaling Studies, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Center for Biological Systems Analysis (ZBSA), Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Ralf Baumeister
- Bioinformatics and Molecular Genetics (Faculty of Biology), Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Spemann Graduate School of Biology and Medicine (SGBM), Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signaling Studies, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Research Training Group (RTG) 1104, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Center for Biological Systems Analysis (ZBSA), Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; ZBMZ Centre for Biochemistry and Molecular Cell Research (Faculty of Medicine), Albert-Ludwigs-University Freiburg, 79106 Freiburg, Germany
| | | | - Kathrin Thedieck
- Bioinformatics and Molecular Genetics (Faculty of Biology), Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Department of Pediatrics, Center for Liver, Digestive and Metabolic Diseases, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, the Netherlands; BIOSS Centre for Biological Signaling Studies, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Department for Neuroscience, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, 26129 Oldenburg, Germany.
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Gatsi R, Schulze B, Rodríguez-Palero MJ, Hernando-Rodríguez B, Baumeister R, Artal-Sanz M. Prohibitin-mediated lifespan and mitochondrial stress implicate SGK-1, insulin/IGF and mTORC2 in C. elegans. PLoS One 2014; 9:e107671. [PMID: 25265021 PMCID: PMC4180437 DOI: 10.1371/journal.pone.0107671] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 08/13/2014] [Indexed: 12/29/2022] Open
Abstract
Lifespan regulation by mitochondrial proteins has been well described, however, the mechanism of this regulation is not fully understood. Amongst the mitochondrial proteins profoundly affecting ageing are prohibitins (PHB-1 and PHB-2). Paradoxically, in C. elegans prohibitin depletion shortens the lifespan of wild type animals while dramatically extending that of metabolically compromised animals, such as daf-2-insulin-receptor mutants. Here we show that amongst the three kinases known to act downstream of daf-2, only loss of function of sgk-1 recapitulates the ageing phenotype observed in daf-2 mutants upon prohibitin depletion. Interestingly, signalling through SGK-1 receives input from an additional pathway, parallel to DAF-2, for the prohibitin-mediated lifespan phenotype. We investigated the effect of prohibitin depletion on the mitochondrial unfolded protein response (UPRmt). Remarkably, the lifespan extension upon prohibitin elimination, of both daf-2 and sgk-1 mutants, is accompanied by suppression of the UPRmt induced by lack of prohibitin. On the contrary, gain of function of SGK-1 results in further shortening of lifespan and a further increase of the UPRmt in prohibitin depleted animals. Moreover, SGK-1 interacts with RICT-1 for the regulation of the UPRmt in a parallel pathway to DAF-2. Interestingly, prohibitin depletion in rict-1 loss of function mutant animals also causes lifespan extension. Finally, we reveal an unprecedented role for mTORC2-SGK-1 in the regulation of mitochodrial homeostasis. Together, these results give further insight into the mechanism of lifespan regulation by mitochondrial function and reveal a cross-talk of mitochondria with two key pathways, Insulin/IGF and mTORC2, for the regulation of ageing and stress response.
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Affiliation(s)
- Roxani Gatsi
- CABD, Centro Andaluz de Biología del Desarrollo, CSIC-Universidad Pablo de Olavide-Junta de Andalucía, Sevilla, Spain
| | - Bettina Schulze
- Centre for Biological Signalling Studies (BIOSS), Albert-Ludwigs-University of Freiburg, Freiburg, Germany
- Laboratory for Bioinformatics and Molecular Genetics, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany
| | - María Jesús Rodríguez-Palero
- CABD, Centro Andaluz de Biología del Desarrollo, CSIC-Universidad Pablo de Olavide-Junta de Andalucía, Sevilla, Spain
| | - Blanca Hernando-Rodríguez
- CABD, Centro Andaluz de Biología del Desarrollo, CSIC-Universidad Pablo de Olavide-Junta de Andalucía, Sevilla, Spain
| | - Ralf Baumeister
- Centre for Biological Signalling Studies (BIOSS), Albert-Ludwigs-University of Freiburg, Freiburg, Germany
- Laboratory for Bioinformatics and Molecular Genetics, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany
- Center for Biochemistry and Molecular Cell Research, Faculty of Medicine, Albert-Ludwigs-University of Freiburg, Freiburg, Germany
| | - Marta Artal-Sanz
- CABD, Centro Andaluz de Biología del Desarrollo, CSIC-Universidad Pablo de Olavide-Junta de Andalucía, Sevilla, Spain
- Centre for Biological Signalling Studies (BIOSS), Albert-Ludwigs-University of Freiburg, Freiburg, Germany
- Laboratory for Bioinformatics and Molecular Genetics, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany
- * E-mail:
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24
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Weiss M, Burgard C, Baumeister R, Strobl F, Rominger A, Bartenstein P, Wallmichrath J, Frick A, Notohamiprodjo M. Magnetic resonance imaging versus lymphoscintigraphy for the assessment of focal lymphatic transport disorders of the lower limb: first experiences. Nuklearmedizin 2014; 53:190-6. [PMID: 24999013 DOI: 10.3413/nukmed-0649-14-03] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Accepted: 06/13/2014] [Indexed: 11/20/2022]
Abstract
PURPOSE To compare the diagnostic accuracy of magnetic resonance imaging (MR-lymphangiography) and lymphoscintigraphy for assessment of focal lesions of the peripheral lymphatic system. Patients with focal lymphatic transport disorders might benefit from surgi-cal interventions. PATIENTS, METHODS We examined by lymphoscintigraphy and MR-lymphangiography a total of 85 lower limbs in 46 consecutive patients (33 women; mean age 41 years; range 9-79 years) presenting with uni- or bilateral lymphedema. MR-lymphangiographies were obtained at isotropic sub-millimeter resolution with a 3.0 Tesla magnet after injection of gadolinium contrast medium. MR-lymphangiography was reviewed by radiologists, whereas lymphoscintigraphy was reviewed by nuclear medicine physicians. The images were examined for localization and distribution of any focal lesions of the lymphatic vessel system. Diagnostic accuracy of the MR-approach was calculated relative to the lymphoscintigraphy gold standard. RESULTS There was substantial correlation of results by the two modalities (κ = 0.62). MR-lymphangiography had sensitivity of 68%, specificity of 91%, positive predictive value of 82%, and negative predictive value of 83%. CONCLUSIONS Imaging findings of both lymphoscintigraphy and MR-lymphangiography showed good diagnostic accuracy. MR-lymphangiography proved more information about anatomic location of focal lesions of the lymphatic vessels, but use of MR-lymphangiography is currently constrained due to the requirement for off-label subcutaneous injection of gadolinium chelates. Consequently, and due to its superior sensitivity lymphoscintigraphy remains the most common imaging method to assess functional lymphatic disorders of the lower limb.
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Affiliation(s)
- M Weiss
- Mayo Weiss MD, Department of Nuclear Medicine, Ludwig-Maximilians-University of Munich, Marchioninistr.15, 81377 Muenchen, Germany, Tel. +49/(0)89/70 95 76 38, E-mail:
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25
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Abstract
A central challenge in post-genomic drug discovery is selection of relevant therapeutic targets from a large pool of candidates, so that resources are invested productively. Key to meeting this challenge is demonstrating target function in disease-related pathways in vivo. The nematode Caenorhabditis elegans, a well-characterized experimental system for genetic analysis of biological regulatory pathways, provides a powerful means of assessing the impact of modulating target function on biological processes, thus facilitating selection of high-value targets.:
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Affiliation(s)
- Ann E Sluder
- Cambria Biosciences LLC, 8A Henshaw St., Woburn, MA 01801, USA.
| | - Ralf Baumeister
- Bio3/Bioinformatics and Molecular Genetics, University of Freiburg, Schaenzlestr. 1, D-79104 Freiburg, Germany
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26
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Schäffer U, Baumeister R, Schulze E. Targeted purification of SnAvi-tagged proteins. Methods Mol Biol 2014; 1177:163-74. [PMID: 24943322 DOI: 10.1007/978-1-4939-1034-2_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
Tandem affinity purification (TAP) is a powerful technique to identify protein complex members. The modular composition of TAP-tags allows two sequential protein enrichment steps and thereby drastically reduces the amount of contaminants. Here, we describe the application of the SnAvi-tag-a TAP-tag useful in different expression systems. Due to its modular composition, this tag is multifunctional and facilitates among others the in vivo visualization of tagged proteins and their cell type specific activation.
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Affiliation(s)
- Ursula Schäffer
- Institute for Biology 3, University of Freiburg, Schänzlestr. 4, 79104, Freiburg, Germany,
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27
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Weinberg F, Schulze E, Fatouros C, Schmidt E, Baumeister R, Brummer T. Expression pattern and first functional characterization of riok-1 in Caenorhabditis elegans. Gene Expr Patterns 2014; 15:124-34. [PMID: 24929033 DOI: 10.1016/j.gep.2014.05.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 05/20/2014] [Accepted: 05/21/2014] [Indexed: 01/08/2023]
Abstract
Rio kinases are atypical serine/threonine kinases that emerge as potential cooperation partners in Ras-driven tumors. In the current study, we performed an RNAi screen in Caenorhabditis elegans to identify suppressors of oncogenic Ras signaling. Aberrant Ras/Raf signaling in C. elegans leads to the formation of a multi-vulva (Muv) phenotype. We found that depletion of riok-1, the C. elegans orthologue of the mammalian RioK1, suppressed the Muv phenotype. By using a promoter GFP construct, we could show that riok-1 is expressed in neuronal cells, the somatic gonad, the vulva, the uterus and the spermatheca. Furthermore, we observed developmental defects in the gonad upon riok-1 knockdown in a wildtype background. Our data suggest that riok-1 is a modulator of the Ras signaling pathway, suggesting implications for novel interventions in the context of Ras-driven tumors.
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Affiliation(s)
- Florian Weinberg
- Institute of Biology III, Faculty of Biology, University of Freiburg, Germany; Centre for Biological Systems Analysis (ZBSA), Freiburg, Germany; IMMZ - Institute of Molecular Medicine and Cell Research, Faculty of Medicine, University of Freiburg, Germany
| | - Ekkehard Schulze
- Institute of Biology III, Faculty of Biology, University of Freiburg, Germany; BIOSS - Centre for Biological Signalling Studies, University of Freiburg, Germany
| | - Chronis Fatouros
- Institute of Biology III, Faculty of Biology, University of Freiburg, Germany; Centre for Biological Systems Analysis (ZBSA), Freiburg, Germany; International Max Planck Research School for Molecular and Cell Biology (IMPRS-MCB), Freiburg, Germany
| | - Enrico Schmidt
- Institute of Biology III, Faculty of Biology, University of Freiburg, Germany; Centre for Biological Systems Analysis (ZBSA), Freiburg, Germany
| | - Ralf Baumeister
- Institute of Biology III, Faculty of Biology, University of Freiburg, Germany; Centre for Biological Systems Analysis (ZBSA), Freiburg, Germany; IMMZ - Institute of Molecular Medicine and Cell Research, Faculty of Medicine, University of Freiburg, Germany; BIOSS - Centre for Biological Signalling Studies, University of Freiburg, Germany
| | - Tilman Brummer
- Institute of Biology III, Faculty of Biology, University of Freiburg, Germany; Centre for Biological Systems Analysis (ZBSA), Freiburg, Germany; IMMZ - Institute of Molecular Medicine and Cell Research, Faculty of Medicine, University of Freiburg, Germany; BIOSS - Centre for Biological Signalling Studies, University of Freiburg, Germany.
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28
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Wolf T, Qi W, Schindler V, Runkel ED, Baumeister R. Doxycyclin ameliorates a starvation-induced germline tumor in C. elegans daf-18/PTEN mutant background. Exp Gerontol 2014; 56:114-22. [PMID: 24746511 DOI: 10.1016/j.exger.2014.04.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 04/04/2014] [Accepted: 04/05/2014] [Indexed: 12/19/2022]
Abstract
Managing available resources is a key necessity of each organism to cope with the environment. The nematode C. elegans responds to nutritional deprivation or harsh environmental conditions with a multitude of developmental adaptations, among them a starvation-induced quiescence at early larval development (L1). daf-18, the C. elegans homolog of the human tumor suppressor gene PTEN, is essential for the maintenance of survival and germline stem cell arrest during the L1 diapause. We show here that daf-18 mutants, independently to their failure to maintain G2 arrest of the primordial germ cells, develop a gonad phenotype after refeeding. This highly penetrant gonadal phenotype is further enhanced by a mutation in shc-1, encoding a protein homologous to the human adaptor ShcA. Features of this phenotype are a tumor-like phenotype encompassing hyper-proliferation of germ cell nuclei and disruption/invasion of the basement membrane surrounding the gonad. The penetrance of this phenotype is reduced by decreasing starvation temperature. In addition, it is also ameliorated in a dose-dependent way by exposure to the antibiotic doxycyclin either during starvation or during subsequent refeeding. Since, in eukaryotic cells, doxycyclin specifically blocks mitochondrial translation, our results suggest that daf-18 and shc-1;daf-18 mutants fail to adapt mitochondrial activity to reduced nutritional availability during early larval developing.
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Affiliation(s)
- Tim Wolf
- Faculty of Biology, Institute of Biology III, Albert-Ludwigs-University, D-79104 Freiburg, Germany
| | - Wenjing Qi
- Faculty of Biology, Institute of Biology III, Albert-Ludwigs-University, D-79104 Freiburg, Germany
| | - Verena Schindler
- Faculty of Biology, Institute of Biology III, Albert-Ludwigs-University, D-79104 Freiburg, Germany
| | - Eva Diana Runkel
- Faculty of Biology, Institute of Biology III, Albert-Ludwigs-University, D-79104 Freiburg, Germany; Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University, D-79104 Freiburg, Germany
| | - Ralf Baumeister
- Faculty of Biology, Institute of Biology III, Albert-Ludwigs-University, D-79104 Freiburg, Germany; Faculty of Medicine, ZBMZ Centre of Biochemistry and Molecular Cell Research, Albert-Ludwigs-University, D-79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University, D-79104 Freiburg, Germany; Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University, D-79104 Freiburg, Germany.
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29
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Cabello J, Sämann J, Gómez-Orte E, Erazo T, Coppa A, Pujol A, Büssing I, Schulze B, Lizcano JM, Ferrer I, Baumeister R, Dalfo E. PDR-1/hParkin negatively regulates the phagocytosis of apoptotic cell corpses in Caenorhabditis elegans. Cell Death Dis 2014; 5:e1120. [PMID: 24625979 PMCID: PMC3973248 DOI: 10.1038/cddis.2014.57] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 12/23/2013] [Accepted: 01/22/2014] [Indexed: 12/28/2022]
Abstract
Apoptotic cell death is an integral part of cell turnover in many tissues, and proper corpse clearance is vital to maintaining tissue homeostasis in all multicellular organisms. Even in tissues with high cellular turnover, apoptotic cells are rarely seen because of efficient clearance mechanisms in healthy individuals. In Caenorhabditis elegans, two parallel and partly redundant conserved pathways act in cell corpse engulfment. The pathway for cytoskeletal rearrangement requires the small GTPase CED-10 Rac1 acting for an efficient surround of the dead cell. The CED-10 Rac pathway is also required for the proper migration of the distal tip cells (DTCs) during the development of the C. elegans gonad. Parkin, the mammalian homolog of the C. elegans PDR-1, interacts with Rac1 in aged human brain and it is also implicated with actin dynamics and cytoskeletal rearrangements in Parkinsons's disease, suggesting that it might act on engulfment. Our genetic and biochemical studies indicate that PDR-1 inhibits apoptotic cell engulfment and DTC migration by ubiquitylating CED-10 for degradation.
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Affiliation(s)
- J Cabello
- CIBIR (Centre for Biomedical Research of La Rioja), C/Piqueras 98, Logroño 26006, Spain
| | - J Sämann
- Bioinformatics and Molecular Genetics (Faculty of Biology), Center for Biochemistry and Molecular Cell Research (Faculty of Medicine), Schänzlestrasse 1, Freiburg 79104, Germany
| | - E Gómez-Orte
- CIBIR (Centre for Biomedical Research of La Rioja), C/Piqueras 98, Logroño 26006, Spain
| | - T Erazo
- Institut de Neurociències, Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Cerdanyola del Vallés, Barcelona 08193, Spain
| | - A Coppa
- Neurometabolic Diseases Laboratory, Institut D'Investigació Biomèdica de Bellvitge (IDIBELL), Hospital Duran i Reynals, L'Hospitalet de Llobregat, Barcelona 08907, Spain
| | - A Pujol
- 1] Neurometabolic Diseases Laboratory, Institut D'Investigació Biomèdica de Bellvitge (IDIBELL), Hospital Duran i Reynals, L'Hospitalet de Llobregat, Barcelona 08907, Spain [2] ICREA (Institució Catalana de Recerca i Estudis avançats), Barcelona, Spain [3] Institute of Neuropathology, University Hospitall Bellvitge - University of Barcelona - IDIBELL, L'Hospitalet de Llobregat, Ciberned, Spain [4] CIBERER (Centro de Investigación Biomédica en Enfermedades Raras), C/ Álvaro de Bazán, 10 Bajo, Valencia 46010, Spain
| | - I Büssing
- Bioinformatics and Molecular Genetics (Faculty of Biology), Center for Biochemistry and Molecular Cell Research (Faculty of Medicine), Schänzlestrasse 1, Freiburg 79104, Germany
| | - B Schulze
- Bioinformatics and Molecular Genetics (Faculty of Biology), Center for Biochemistry and Molecular Cell Research (Faculty of Medicine), Schänzlestrasse 1, Freiburg 79104, Germany
| | - J M Lizcano
- Institut de Neurociències, Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Cerdanyola del Vallés, Barcelona 08193, Spain
| | - I Ferrer
- Institute of Neuropathology, University Hospitall Bellvitge - University of Barcelona - IDIBELL, L'Hospitalet de Llobregat, Ciberned, Spain
| | - R Baumeister
- 1] Bioinformatics and Molecular Genetics (Faculty of Biology), Center for Biochemistry and Molecular Cell Research (Faculty of Medicine), Schänzlestrasse 1, Freiburg 79104, Germany [2] Centre for Biological Signaling Studies (bioss), University of Freiburg, Freiburg 79104, Germany [3] FRIAS Freiburg Institute for Advanced Studies, Section Life Sciences (LIFENET), University of Freiburg, Schaenzlestrasse 1, Freiburg 79104, Germany
| | - E Dalfo
- 1] Bioinformatics and Molecular Genetics (Faculty of Biology), Center for Biochemistry and Molecular Cell Research (Faculty of Medicine), Schänzlestrasse 1, Freiburg 79104, Germany [2] Neurometabolic Diseases Laboratory, Institut D'Investigació Biomèdica de Bellvitge (IDIBELL), Hospital Duran i Reynals, L'Hospitalet de Llobregat, Barcelona 08907, Spain [3] Institute of Neuropathology, University Hospitall Bellvitge - University of Barcelona - IDIBELL, L'Hospitalet de Llobregat, Ciberned, Spain [4] CIBERER (Centro de Investigación Biomédica en Enfermedades Raras), C/ Álvaro de Bazán, 10 Bajo, Valencia 46010, Spain
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Runkel ED, Baumeister R, Schulze E. Mitochondrial stress: balancing friend and foe. Exp Gerontol 2014; 56:194-201. [PMID: 24603155 DOI: 10.1016/j.exger.2014.02.013] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Revised: 02/21/2014] [Accepted: 02/22/2014] [Indexed: 12/15/2022]
Abstract
Mitochondria are vital organelles of the aerobic eukaryotic cell. Their dysfunction associates with aging and widespread age-related diseases. To sustain mitochondrial integrity, the cell executes a distinct set of stress-induced protective responses. The mitochondrial unfolded protein response (UPR(mt)) is a response of the cell to mitochondrial damage. The transcription factor ATFS-1 triggers UPR(mt) effector gene expression in the nucleus. The selective exclusion of ATFS-1 from mitochondrial import by stress-induced alterations of the mitochondrial membrane potential is currently discussed as key activation mechanism. Surprisingly, UPR(mt) activation often coincides with a lifespan extension in Caenorhabditis elegans and the same has recently been reported for mammalian cells. This review summarizes the current model of the UPR(mt), its inducers, and its crosstalk with other cellular stress responses. It focuses on the role of mitochondrial function as a regulator of aging and longevity.
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Affiliation(s)
- Eva Diana Runkel
- Faculty of Biology, Institute of Biology III, Germany; BIOSS Centre for Biological Signalling Studies, Germany; Spemann Graduate School of Biology and Medicine, Germany
| | - Ralf Baumeister
- Faculty of Biology, Institute of Biology III, Germany; Faculty of Medicine, ZBMZ Center of Biochemistry and Molecular Cell Research, Germany; BIOSS Centre for Biological Signalling Studies, Germany; Spemann Graduate School of Biology and Medicine, Germany
| | - Ekkehard Schulze
- Faculty of Biology, Institute of Biology III, Germany; BIOSS Centre for Biological Signalling Studies, Germany.
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31
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Thedieck K, Holzwarth B, Prentzell MT, Boehlke C, Kläsener K, Ruf S, Sonntag AG, Maerz L, Grellscheid SN, Kremmer E, Nitschke R, Kuehn EW, Jonker JW, Groen AK, Reth M, Hall MN, Baumeister R. Inhibition of mTORC1 by astrin and stress granules prevents apoptosis in cancer cells. Cell 2013; 154:859-74. [PMID: 23953116 DOI: 10.1016/j.cell.2013.07.031] [Citation(s) in RCA: 207] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 04/03/2013] [Accepted: 07/23/2013] [Indexed: 12/21/2022]
Abstract
Mammalian target of rapamycin complex 1 (mTORC1) controls growth and survival in response to metabolic cues. Oxidative stress affects mTORC1 via inhibitory and stimulatory inputs. Whereas downregulation of TSC1-TSC2 activates mTORC1 upon oxidative stress, the molecular mechanism of mTORC1 inhibition remains unknown. Here, we identify astrin as an essential negative mTORC1 regulator in the cellular stress response. Upon stress, astrin inhibits mTORC1 association and recruits the mTORC1 component raptor to stress granules (SGs), thereby preventing mTORC1-hyperactivation-induced apoptosis. In turn, balanced mTORC1 activity enables expression of stress factors. By identifying astrin as a direct molecular link between mTORC1, SG assembly, and the stress response, we establish a unifying model of mTORC1 inhibition and activation upon stress. Importantly, we show that in cancer cells, apoptosis suppression during stress depends on astrin. Being frequently upregulated in tumors, astrin is a potential clinically relevant target to sensitize tumors to apoptosis.
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Affiliation(s)
- Kathrin Thedieck
- Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany.
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32
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Thedieck K, Holzwarth B, Prentzell M, Boehlke C, Kläsener K, Ruf S, Sonntag A, Maerz L, Grellscheid SN, Kremmer E, Nitschke R, Kuehn E, Jonker J, Groen A, Reth M, Hall M, Baumeister R. Inhibition of mTORC1 by Astrin and Stress Granules Prevents Apoptosis in Cancer Cells. Cell 2013. [DOI: 10.1016/j.cell.2013.10.036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Runkel ED, Liu S, Baumeister R, Schulze E. Surveillance-activated defenses block the ROS-induced mitochondrial unfolded protein response. PLoS Genet 2013; 9:e1003346. [PMID: 23516373 PMCID: PMC3597513 DOI: 10.1371/journal.pgen.1003346] [Citation(s) in RCA: 136] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Accepted: 01/11/2013] [Indexed: 01/01/2023] Open
Abstract
Disturbance of cellular functions results in the activation of stress-signaling pathways that aim at restoring homeostasis. We performed a genome-wide screen to identify components of the signal transduction of the mitochondrial unfolded protein response (UPR(mt)) to a nuclear chaperone promoter. We used the ROS generating complex I inhibitor paraquat to induce the UPR(mt), and we employed RNAi exposure post-embryonically to allow testing genes whose knockdown results in embryonic lethality. We identified 54 novel regulators of the ROS-induced UPR(mt). Activation of the UPR(mt), but not of other stress-signaling pathways, failed when homeostasis of basic cellular mechanisms such as translation and protein transport were impaired. These mechanisms are monitored by a recently discovered surveillance system that interprets interruption of these processes as pathogen attack and depends on signaling through the JNK-like MAP-kinase KGB-1. Mutation of kgb-1 abrogated the inhibition of ROS-induced UPR(mt), suggesting that surveillance-activated defenses specifically inhibit the UPR(mt) but do not compromise activation of the heat shock response, the UPR of the endoplasmic reticulum, or the SKN-1/Nrf2 mediated response to cytosolic stress. In addition, we identified PIFK-1, the orthologue of the Drosophila PI 4-kinase four wheel drive (FWD), and found that it is the only known factor so far that is essential for the unfolded protein responses of both mitochondria and endoplasmic reticulum. This suggests that both UPRs may share a common membrane associated mechanism.
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Affiliation(s)
- Eva D. Runkel
- Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University of Freiburg, Freiburg, Germany
- Laboratory for Bioinformatics and Molecular Genetics, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany
| | - Shu Liu
- Laboratory for Bioinformatics and Molecular Genetics, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany
| | - Ralf Baumeister
- Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University of Freiburg, Freiburg, Germany
- Laboratory for Bioinformatics and Molecular Genetics, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany
- Center for Biochemistry and Molecular Cell Research, Faculty of Medicine, Albert-Ludwigs-University of Freiburg, Freiburg, Germany
- Centre for Biological Signaling Studies (BIOSS), Albert-Ludwigs-University of Freiburg, Freiburg, Germany
- * E-mail:
| | - Ekkehard Schulze
- Laboratory for Bioinformatics and Molecular Genetics, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany
- Centre for Biological Signaling Studies (BIOSS), Albert-Ludwigs-University of Freiburg, Freiburg, Germany
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Strobl F, Weiss M, Wallmichrath J, Baumeister R, Reiser M, Notohamiprodjo M. Die MR-Lymphangiografie in der präoperativen Diagnostik des fokalen „dermal backflow“ bei peripheren Lymphödemen. HANDCHIR MIKROCHIR P 2012. [DOI: 10.1055/s-0032-1323839] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Affiliation(s)
| | - M. Weiss
- Klinik und Poliklinik für Nuklearmedizin
| | | | - R. Baumeister
- Handchirurgie, Plastische Chirurgie, Ästhetische Chirurgie
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Wallmichrath J, Baumeister R, Giunta R, Notohamiprodjo M, Frick A. Die Vielfalt in der chirurgischen Therapie beim Lymphödem – was ist aktuell? HANDCHIR MIKROCHIR P 2012; 44:334-42. [DOI: 10.1055/s-0032-1323840] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Affiliation(s)
| | - R. Baumeister
- Handchirurgie, Plastische Chirurgie, Äshetische Chirurgie
| | - R. Giunta
- Handchirurgie, Plastische Chirurgie, Äshetische Chirurgie
| | - M. Notohamiprodjo
- Institut für Klinische Radiologie, alle Klinikum der Ludwig-Maximilians-Universität, München
| | - A. Frick
- Handchirurgie, Plastische Chirurgie, Äshetische Chirurgie
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Qi W, Huang X, Neumann-Haefelin E, Schulze E, Baumeister R. Cell-nonautonomous signaling of FOXO/DAF-16 to the stem cells of Caenorhabditis elegans. PLoS Genet 2012; 8:e1002836. [PMID: 22916022 PMCID: PMC3420913 DOI: 10.1371/journal.pgen.1002836] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 06/04/2012] [Indexed: 11/25/2022] Open
Abstract
In Caenorhabditis elegans (C. elegans), the promotion of longevity by the transcription factor DAF-16 requires reduced insulin/IGF receptor (IIR) signaling or the ablation of the germline, although the reason for the negative impact of germ cells is unknown. FOXO/DAF-16 activity inhibits germline proliferation in both daf-2 mutants and gld-1 tumors. In contrast to its function as a germline tumor suppressor, we now provide evidence that somatic DAF-16 in the presence of IIR signaling can also result in tumorigenic activity, which counteracts robust lifespan extension. In contrast to the cell-autonomous IIR signaling, which is required for larval germline proliferation, activation of DAF-16 in the hypodermis results in hyperplasia of the germline and disruption of the surrounding basement membrane. SHC-1 adaptor protein and AKT-1 kinase antagonize, whereas AKT-2 and SGK-1 kinases promote, this cell-nonautonomous DAF-16 function. Our data suggest that a functional balance of DAF-16 activities in different tissues determines longevity and reveals a novel, cell-nonautonomous role of FOXO/DAF-16 to affect stem cells. Previous studies have shown that DAF–16/FOXO transcription factor promotes longevity and stress resistance and inhibits tumor progression in the absence of insulin signaling. Here we show that active DAF-16 in the epidermis can shorten lifespan by promoting a tumorous germline phenotype. In contrast to the known inhibitory effect of insulin signaling upon DAF-16, an active insulin and PI3K signaling are required for DAF-16–mediated signaling to the germline. In addition, AKT-1– and SHC-1–mediated JNK signaling antagonize AKT-2 and SGK-1 to affect the reproductive system. This is to our knowledge the first report about a detrimental effect of DAF-16 on lifespan. Furthermore it emphasizes that DAF-16 activity is highly dependent on the cellular context and communication between different tissues.
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Affiliation(s)
- Wenjing Qi
- Faculty of Biology, Bioinformatics, and Molecular Genetics, Center for Biochemistry and Molecular Cell Research, Freiburg, Germany
- Faculty of Medicine, Center for Biochemistry and Molecular Cell Research, Freiburg, Germany
| | - Xu Huang
- Faculty of Biology, Bioinformatics, and Molecular Genetics, Center for Biochemistry and Molecular Cell Research, Freiburg, Germany
- Faculty of Medicine, Center for Biochemistry and Molecular Cell Research, Freiburg, Germany
| | | | - Ekkehard Schulze
- Faculty of Biology, Bioinformatics, and Molecular Genetics, Center for Biochemistry and Molecular Cell Research, Freiburg, Germany
- Faculty of Medicine, Center for Biochemistry and Molecular Cell Research, Freiburg, Germany
| | - Ralf Baumeister
- Faculty of Biology, Bioinformatics, and Molecular Genetics, Center for Biochemistry and Molecular Cell Research, Freiburg, Germany
- Faculty of Medicine, Center for Biochemistry and Molecular Cell Research, Freiburg, Germany
- Centre for Biological Signaling Studies (BIOSS), University of Freiburg, Freiburg, Germany
- FRIAS Freiburg Institute for Advanced Studies, Section Life Sciences (LIFENET), University of Freiburg, Freiburg, Germany
- * E-mail:
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Fatouros C, Pir GJ, Biernat J, Koushika SP, Mandelkow E, Mandelkow EM, Schmidt E, Baumeister R. Inhibition of tau aggregation in a novel Caenorhabditis elegans model of tauopathy mitigates proteotoxicity. Hum Mol Genet 2012; 21:3587-603. [PMID: 22611162 DOI: 10.1093/hmg/dds190] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Increased Tau protein amyloidogenicity has been causatively implicated in several neurodegenerative diseases, collectively called tauopathies. In pathological conditions, Tau becomes hyperphosphorylated and forms intracellular aggregates. The deletion of K280, which is a mutation that commonly appears in patients with frontotemporal dementia with Parkinsonism linked to chromosome 17, enhances Tau aggregation propensity (pro-aggregation). In contrast, introduction of the I277P and I308P mutations prevents β-sheet formation and subsequent aggregation (anti-aggregation). In this study, we created a tauopathy model by expressing pro- or anti-aggregant Tau species in the nervous system of Caenorhabditis elegans. Animals expressing the highly amyloidogenic Tau species showed accelerated Tau aggregation and pathology manifested by severely impaired motility and evident neuronal dysfunction. In addition, we observed that the axonal transport of mitochondria was perturbed in these animals. Control animals expressing the anti-aggregant combination had rather mild phenotype. We subsequently tested several Tau aggregation inhibitor compounds and observed a mitigation of Tau proteotoxicity. In particular, a novel compound that crosses the blood-brain barrier of mammals proved effective in ameliorating the motility as well as delaying the accumulation of neuronal defects. Our study establishes a new C. elegans model of Tau aggregation-mediated toxicity and supports the emerging notion that inhibiting the nucleation of Tau aggregation can be neuroprotective.
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Affiliation(s)
- Chronis Fatouros
- Institute of Biology III, University of Freiburg, 79104 Freiburg, Germany
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Dalle Pezze P, Sonntag AG, Thien A, Prentzell MT, Gödel M, Fischer S, Neumann-Haefelin E, Huber TB, Baumeister R, Shanley DP, Thedieck K. A dynamic network model of mTOR signaling reveals TSC-independent mTORC2 regulation. Sci Signal 2012; 5:ra25. [PMID: 22457331 DOI: 10.1126/scisignal.2002469] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The kinase mammalian target of rapamycin (mTOR) exists in two multiprotein complexes (mTORC1 and mTORC2) and is a central regulator of growth and metabolism. Insulin activation of mTORC1, mediated by phosphoinositide 3-kinase (PI3K), Akt, and the inhibitory tuberous sclerosis complex 1/2 (TSC1-TSC2), initiates a negative feedback loop that ultimately inhibits PI3K. We present a data-driven dynamic insulin-mTOR network model that integrates the entire core network and used this model to investigate the less well understood mechanisms by which insulin regulates mTORC2. By analyzing the effects of perturbations targeting several levels within the network in silico and experimentally, we found that, in contrast to current hypotheses, the TSC1-TSC2 complex was not a direct or indirect (acting through the negative feedback loop) regulator of mTORC2. Although mTORC2 activation required active PI3K, this was not affected by the negative feedback loop. Therefore, we propose an mTORC2 activation pathway through a PI3K variant that is insensitive to the negative feedback loop that regulates mTORC1. This putative pathway predicts that mTORC2 would be refractory to Akt, which inhibits TSC1-TSC2, and, indeed, we found that mTORC2 was insensitive to constitutive Akt activation in several cell types. Our results suggest that a previously unknown network structure connects mTORC2 to its upstream cues and clarifies which molecular connectors contribute to mTORC2 activation.
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Affiliation(s)
- Piero Dalle Pezze
- Institute for Ageing and Health, Newcastle University, Campus for Ageing and Vitality, Newcastle upon Tyne, UK
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Liu S, Schulze E, Baumeister R. Temperature- and touch-sensitive neurons couple CNG and TRPV channel activities to control heat avoidance in Caenorhabditis elegans. PLoS One 2012; 7:e32360. [PMID: 22448218 PMCID: PMC3308950 DOI: 10.1371/journal.pone.0032360] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Accepted: 01/27/2012] [Indexed: 01/08/2023] Open
Abstract
Background Any organism depends on its ability to sense temperature and avoid noxious heat. The nematode Caenorhabditis elegans responds to noxious temperatures exceeding ∼35°C and also senses changes in its environmental temperature in the range between 15 and 25°C. The neural circuits and molecular mechanisms involved in thermotaxis have been successfully studied, whereas details of the thermal avoidance behavior remain elusive. In this work, we investigate neurological and molecular aspects of thermonociception using genetic, cell biological and physiological approaches. Methodology/Principal Findings We show here that the thermosensory neurons AFD, in addition to sensing temperature within the range within which the animals can thrive, also contribute to the sensation of noxious temperatures resulting in a reflex-like escape reaction. Distinct sets of interneurons are involved in transmitting thermonociception and thermotaxis, respectively. Loss of AFD is partially compensated by the activity of a pair of multidendritic, polymodal neurons, FLP, whereas laser ablation of both types of neurons abrogated the heat response in the head of the animals almost completely. A third pair of heat sensory neurons, PHC, is situated in the tail. We find that the thermal avoidance response requires the cell autonomous function of cGMP dependent Cyclic Nucleotide-Gated (CNG) channels in AFD, and the heat- and capsaicin-sensitive Transient Receptor Potential Vanilloid (TRPV) channels in the FLP and PHC sensory neurons. Conclusions/Significance Our results identify distinct thermal responses mediated by a single neuron, but also show that parallel nociceptor circuits and molecules may be used as back-up strategies to guarantee fast and efficient responses to potentially detrimental stimuli.
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Affiliation(s)
- Shu Liu
- Laboratory for Bioinformatics and Molecular Genetics, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany
| | - Ekkehard Schulze
- Laboratory for Bioinformatics and Molecular Genetics, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany
| | - Ralf Baumeister
- Laboratory for Bioinformatics and Molecular Genetics, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany
- Center for Biochemistry and Molecular Cell Research, Faculty of Medicine, and Freiburg Institute for Advanced Studies, School of Life Sciences (FRIAS LIFENET), Albert-Ludwigs-University of Freiburg, Freiburg, Germany
- Centre for Biological Signalling Studies (BIOSS), Albert-Ludwigs-University of Freiburg, Freiburg, Germany
- * E-mail:
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Rizzini L, Favory JJ, Cloix C, Faggionato D, O'Hara A, Kaiserli E, Baumeister R, Schäfer E, Nagy F, Jenkins GI, Ulm R. Perception of UV-B by the Arabidopsis UVR8 protein. Science 2011; 332:103-6. [PMID: 21454788 DOI: 10.1126/science.1200660] [Citation(s) in RCA: 677] [Impact Index Per Article: 52.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
To optimize their growth and survival, plants perceive and respond to ultraviolet-B (UV-B) radiation. However, neither the molecular identity of the UV-B photoreceptor nor the photoperception mechanism is known. Here we show that dimers of the UVR8 protein perceive UV-B, probably by a tryptophan-based mechanism. Absorption of UV-B induces instant monomerization of the photoreceptor and interaction with COP1, the central regulator of light signaling. Thereby this signaling cascade controlled by UVR8 mediates UV-B photomorphogenic responses securing plant acclimation and thus promotes survival in sunlight.
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Affiliation(s)
- Luca Rizzini
- Faculty of Biology, Institute of Biology II, University of Freiburg, D-79104 Freiburg, Germany
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Lankisch TO, Metzger J, Negm AA, Vosskuhl K, Schiffer E, Siwy J, Weismüller TJ, Schneider AS, Thedieck K, Baumeister R, Zürbig P, Weissinger EM, Manns MP, Mischak H, Wedemeyer J. Bile proteomic profiles differentiate cholangiocarcinoma from primary sclerosing cholangitis and choledocholithiasis. Hepatology 2011; 53:875-84. [PMID: 21374660 DOI: 10.1002/hep.24103] [Citation(s) in RCA: 124] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Accepted: 11/24/2010] [Indexed: 12/17/2022]
Abstract
UNLABELLED Early detection of malignant biliary tract diseases, especially cholangiocarcinoma (CC) in patients with primary sclerosing cholangitis (PSC), is very difficult and often comes too late to give the patient a therapeutic benefit. We hypothesize that bile proteomic analysis distinguishes CC from nonmalignant lesions. We used capillary electrophoresis mass spectrometry (CE-MS) to identify disease-specific peptide patterns in patients with choledocholithiasis (n = 16), PSC (n = 18), and CC (n = 16) in a training set. A model for differentiation of choledocholithiasis from PSC and CC (PSC/CC model) and another model distinguishing CC from PSC (CC model) were subsequently validated in independent cohorts (choledocholithiasis [n = 14], PSC [n = 18] and CC [n = 25]). Peptides were characterized by sequencing. Application of the PSC/CC model in the independent test cohort resulted in correct exclusion of 12/14 bile samples from patients with choledocholithiasis and identification of 40/43 patients with PSC or CC (86% specificity, 93% sensitivity). The corresponding receiver operating characteristic (ROC) analysis revealed an area under the curve (AUC) of 0.93 (95% confidence interval [CI]: 0.82-0.98, P = 0.0001). The CC model succeeded in an accurate detection of 14/18 bile samples from patients with PSC and 21/25 samples with CC (78% specificity, 84% sensitivity) in the independent cohort, resulting in an AUC value of 0.87 (95% CI: 0.73-0.95, P = 0.0001) in ROC analysis. Eight out of 10 samples of patients with CC complicating PSC were identified. CONCLUSION Bile proteomic analysis discriminates benign conditions from CC accurately. This method may become a diagnostic tool in future as it offers a new possibility to diagnose malignant bile duct disease and thus enables efficient therapy particularly in patients with PSC.
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Affiliation(s)
- Tim O Lankisch
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany.
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Fusco D, Vargiolu M, Vidone M, Mariani E, Pennisi LF, Bonora E, Capellari S, Dirnberger D, Baumeister R, Martinelli P, Romeo G. The RET51/FKBP52 complex and its involvement in Parkinson disease. Hum Mol Genet 2010; 19:2804-16. [PMID: 20442138 DOI: 10.1093/hmg/ddq181] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The tyrosine kinase receptor RET51 is expressed in distinct families of neurons where it promotes different functions. FKBP52 is an immunophilin with neuroprotective effects on different kinds of neurons. In this paper, we demonstrate that RET51 activation by both glial cell line-derived neurotrophic factor (GDNF) and NGF triggers the formation of RET51/FKBP52 complex. The substitution of the tyrosine 905 of RET51, a key residue phosphorylated by both GDNF and NGF, disrupts the RET51/FKBP52 complex. NGF and GDNF have a functional role in dopaminergic (DA) neurons where RET51 and FKBP52 are expressed with a yet undefined function. To clarify if RET51/FKBP52 complex should exert its function in DA neurons, we used an indirect approach by screening the genes encoding for RET51 and FKBP52 in a group of 30 Parkinson's disease patients. The degeneration of DA neurons is the main feature of PD, which is associated to a complex multifactorial aetiology combining environmental, age-related and genetic factors. We found a compound heterozygous carrying two mutations in RET and FKBP52 that are sufficient to disrupt the RET51/FKBP52 complex, indicating its potential role in PD.
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Affiliation(s)
- Daniela Fusco
- Unità di Genetica Medica, Policlinico Universitario S. Orsola-Malpighi, Bologna, Italy
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Neumann-Haefelin E, Kramer-Zucker A, Slanchev K, Hartleben B, Noutsou F, Martin K, Wanner N, Ritter A, Gödel M, Pagel P, Fu X, Müller A, Baumeister R, Walz G, Huber TB. A model organism approach: defining the role of Neph proteins as regulators of neuron and kidney morphogenesis. Hum Mol Genet 2010; 19:2347-59. [PMID: 20233749 DOI: 10.1093/hmg/ddq108] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Mutations of the immunoglobulin superfamily proteins nephrin and Neph1 lead to congenital nephrotic syndrome in humans or mice. Neph proteins are three closely related molecules that are evolutionarily conserved and mediate cell recognition. Their importance for morphogenetic processes including the formation of the kidney filtration barrier in vertebrates and synaptogenesis in Caenorhabditis elegans has recently been uncovered. However, the individual morphogenetic function of mammalian Neph1-3 isoforms remained elusive. We demonstrate now that the Neph/nephrin family proteins can form cell-cell adhesion modules across species. Expression of all three mammalian Neph isoforms partially rescued mutant C. elegans lacking their Neph homolog syg-1 and restored synapse formation, suggesting a functional redundancy between the three isoforms. Strikingly, the rescue of defective synaptic connectivity was prevented by deletion of the highly conserved cytoplasmic PSD95/Dlg/ZO-1-binding motif of SYG-1/Neph proteins, indicating the critical role of this intracellular signaling motif for SYG-1/Neph-dependent morphogenetic events. To determine the significance of Neph isoform redundancy for vertebrate kidney development, we analyzed the expression pattern and the functional role of Neph proteins in zebrafish. In situ hybridizations identified zNeph1 and zNeph2 as glomerular proteins. Morpholino knockdown of either zNeph1 or zNeph2 resulted in loss of slit diaphragms and leakiness of the glomerular filtration barrier. This is the first report utilizing C. elegans to study mammalian Neph/nephrin protein function and to demonstrate a functional overlap of Neph1-3 proteins. Furthermore, we identify Neph2 as a novel critical regulator of glomerular function, indicating that both Neph1 and Neph2 are required for glomerular maintenance and development.
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Schäffer U, Schlosser A, Müller KM, Schäfer A, Katava N, Baumeister R, Schulze E. SnAvi--a new tandem tag for high-affinity protein-complex purification. Nucleic Acids Res 2010; 38:e91. [PMID: 20047968 PMCID: PMC2847239 DOI: 10.1093/nar/gkp1178] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Systematic tandem-affinity-purification (TAP) of protein complexes was tremendously successful in yeast and has changed the general concept of how we understand protein function in eukaryotic cells. The transfer of this method to other model organisms has been difficult and may require specific adaptations. We were especially interested to establish a cell-type-specific TAP system for Caenorhabditis elegans, a model animal well suited to high-throughput analysis, proteomics and systems biology. By combining the high-affinity interaction between in vivo biotinylated target-proteins and streptavidin with the usage of a newly identified epitope of the publicly shared SB1 monoclonal antibody we created a novel in vivo fluorescent tag, the SnAvi-Tag. We show the versatile application of the SnAvi-Tag in Escherichia coli, vertebrate cells and in C. elegans for tandem affinity purification of protein complexes, western blotting and also for the in vivo sub-cellular localization of labelled proteins.
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Affiliation(s)
- Ursula Schäffer
- Bioinformatics and Molecular Genetics, ZBMZ, Institute for Biology, ZBSA-Center for Systems Biology, Albert-Ludwigs-Universitaet Freiburg, 79104 Freiburg, Germany
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45
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Vargiolu M, Fusco D, Kurelac I, Dirnberger D, Baumeister R, Morra I, Melcarne A, Rimondini R, Romeo G, Bonora E. The tyrosine kinase receptor RET interacts in vivo with aryl hydrocarbon receptor-interacting protein to alter survivin availability. J Clin Endocrinol Metab 2009; 94:2571-8. [PMID: 19366855 DOI: 10.1210/jc.2008-1980] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
CONTEXT RET is a tyrosine kinase transmembrane receptor expressed in two main alternative isoforms: RET9 and RET51. RET transduces a positive signal leading to survival, differentiation, or migration in the presence of its ligand glial cell line-derived neurotrophic factor, whereas in its absence a proapoptotic fragment that initiates a negative signaling for apoptosis is generated. The signal transduction mechanisms leading to apoptosis are still unclear. OBJECTIVE To shed light on the mechanisms of RET-induced apoptosis, we searched for novel interactors of RET51. DESIGN The "split ubiquitin yeast two-hybrid system" was used with RET51 as bait against a human brain expression library. RESULTS We identified aryl hydrocarbon receptor-interacting protein (AIP), a cochaperone recently found mutated in pituitary adenoma patients, as a novel interactor of RET. We showed that RET interacts specifically with AIP both in mammalian cell lines and in vivo in the pituitary gland, regardless of the presence of pituitary adenoma-specific mutations. AIP and RET genes were sequenced in 28 pituitary adenoma, but no relevant mutations were found. In addition, we identified the proapoptotic domain of RET as responsible for the interaction with AIP. Finally, we demonstrated that the AIP-RET interaction does not require RET kinase activity or kinase-dependent signal transduction and that it prevents the formation of the AIP-survivin complex. CONCLUSIONS The identification of the AIP-RET complex represents a starting point to study key cellular processes involved in RET-induced apoptosis.
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Affiliation(s)
- Manuela Vargiolu
- Unità di Genetica Medica, Policlinico Universitario S. Orsola-Malpighi, 40138 Bologna, Italy
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Vargiolu M, Fusco D, Kurelac I, Dirnberger D, Baumeister R, Morra I, Melcarne A, Rimondini R, Romeo G, Bonora E. The Tyrosine Kinase Receptor RET Interacts in Vivo with Aryl Hydrocarbon Receptor-Interacting Protein to Alter Survivin Availability. Mol Endocrinol 2009. [DOI: 10.1210/mend.23.6.9996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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47
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Notohamiprodjo M, Weiss M, Baumeister R, Jakobs T, Glaser C, Reiser MF, Herrmann KA. MR-Lymphangiographie bei 3T-Korrelation mit der Lymphszintigraphie. ROFO-FORTSCHR RONTG 2009. [DOI: 10.1055/s-0029-1221561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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48
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Sämann J, Hegermann J, von Gromoff E, Eimer S, Baumeister R, Schmidt E. Caenorhabditits elegans LRK-1 and PINK-1 act antagonistically in stress response and neurite outgrowth. J Biol Chem 2009; 284:16482-16491. [PMID: 19251702 DOI: 10.1074/jbc.m808255200] [Citation(s) in RCA: 144] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mutations in two genes encoding the putative kinases LRRK2 and PINK1 have been associated with inherited variants of Parkinson disease. The physiological role of both proteins is not known at present, but studies in model organisms have linked their mutants to distinct aspects of mitochondrial dysfunction, increased vulnerability to oxidative and endoplasmic reticulum stress, and intracellular protein sorting. Here, we show that a mutation in the Caenorhabditits elegans homologue of the PTEN-induced kinase pink-1 gene resulted in reduced mitochondrial cristae length and increased paraquat sensitivity of the nematode. Moreover, the mutants also displayed defects in axonal outgrowth of a pair of canal-associated neurons. We demonstrate that in the absence of lrk-1, the C. elegans homologue of human LRRK2, all phenotypic aspects of pink-1 loss-of-function mutants were suppressed. Conversely, the hypersensitivity of lrk-1 mutant animals to the endoplasmic reticulum stressor tunicamycin was reduced in a pink-1 mutant background. These results provide the first evidence of an antagonistic role of PINK-1 and LRK-1. Due to the similarity of the C. elegans proteins to human LRRK2 and PINK1, we suggest a common role of both factors in cellular functions including stress response and regulation of neurite outgrowth. This study might help to link pink-1/PINK1 and lrk-1/LRRK2 function to the pathological processes resulting from Parkinson disease-related mutants in both genes, the first manifestations of which are cytoskeletal defects in affected neurons.
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Affiliation(s)
- Julia Sämann
- From Bioinformatics and Molecular Genetics (Faculty of Biology), ZBMZ (Faculty of Medicine), and ZBSA-Center for Systems Biology, Albert-Ludwigs-Universitaet Freiburg, 79104
| | - Jan Hegermann
- Freiburg and the European Neuroscience Institute (ENI) and Deutsche Forsch ungs ge mein schaft (DFG) Research Center for Molecular Physiology of the Brain (CMPB), University Medical Faculty, 37077 Göttingen, Germany
| | - Erika von Gromoff
- From Bioinformatics and Molecular Genetics (Faculty of Biology), ZBMZ (Faculty of Medicine), and ZBSA-Center for Systems Biology, Albert-Ludwigs-Universitaet Freiburg, 79104
| | - Stefan Eimer
- Freiburg and the European Neuroscience Institute (ENI) and Deutsche Forsch ungs ge mein schaft (DFG) Research Center for Molecular Physiology of the Brain (CMPB), University Medical Faculty, 37077 Göttingen, Germany
| | - Ralf Baumeister
- From Bioinformatics and Molecular Genetics (Faculty of Biology), ZBMZ (Faculty of Medicine), and ZBSA-Center for Systems Biology, Albert-Ludwigs-Universitaet Freiburg, 79104; Freiburg Institute for Advanced Studies, School of Life Sciences (LIFENET), and Centre for Biological Signalling Studies (BIOSS), 79104.
| | - Enrico Schmidt
- From Bioinformatics and Molecular Genetics (Faculty of Biology), ZBMZ (Faculty of Medicine), and ZBSA-Center for Systems Biology, Albert-Ludwigs-Universitaet Freiburg, 79104
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Neumann-Haefelin E, Qi W, Finkbeiner E, Walz G, Baumeister R, Hertweck M. SHC-1/p52Shc targets the insulin/IGF-1 and JNK signaling pathways to modulate life span and stress response in C. elegans. Genes Dev 2008; 22:2721-35. [PMID: 18832074 DOI: 10.1101/gad.478408] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Correlative evidence links stress, accumulation of oxidative cellular damage, and aging in several species. Genetic studies in species ranging from yeast to mammals revealed several pathways regulating stress response and life span, including caloric intake, mitochondrial respiration, insulin/IGF-1 (IIS), and JNK (c-Jun N-terminal kinase) signaling. How IIS and JNK signaling cross-talk to defend against diverse stressors contributing to aging is of critical importance but, so far, only poorly understood. In this study, we demonstrate that the adaptor protein SHC-1, the Caenorhabditis elegans homolog of human p52Shc, coordinates mechanisms of stress response and aging. Using genetic and biochemical approaches, we discover that SHC-1 not only opposes IIS but also activates JNK signaling. Loss of shc-1 function results in accelerated aging and enhanced sensitivity to heat, oxidative stress, and heavy metals, whereas expression of human p52Shc rescues the shc-1 mutant phenotype. SHC-1 acts upstream of the insulin/IGF receptor DAF-2 and the PI3 kinase AGE-1 and directly interacts with DAF-2. Moreover, SHC-1 activates JNK signaling by binding to MEK-1 kinase. Both aspects converge on controlling the nuclear translocation and activation of the FOXO transcription factor DAF-16. Our findings establish C. elegans SHC-1 as a critical scaffold that directly cross-connects the two parallel JNK and IIS pathways and help to explain how these signaling cascades cooperate to ascertain normal stress response and life span in C. elegans.
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Affiliation(s)
- Elke Neumann-Haefelin
- Bioinformatics and Molecular Genetics (Faculty of Biology), Center for Biochemistry and Molecular Cell Research (Faculty of Medicine), University of Freiburg, D-79104 Freiburg, Germany
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50
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Schöbel S, Neumann S, Hertweck M, Dislich B, Kuhn PH, Kremmer E, Seed B, Baumeister R, Haass C, Lichtenthaler SF. A novel sorting nexin modulates endocytic trafficking and alpha-secretase cleavage of the amyloid precursor protein. J Biol Chem 2008; 283:14257-68. [PMID: 18353773 DOI: 10.1074/jbc.m801531200] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Ectodomain shedding of the amyloid precursor protein (APP) by the two proteases alpha- and beta-secretase is a key regulatory event in the generation of the Alzheimer disease amyloid beta peptide (Abeta). beta-Secretase catalyzes the first step in Abeta generation, whereas alpha-secretase cleaves within the Abeta domain, prevents Abeta generation, and generates a secreted form of APP with neuroprotective properties. At present, little is known about the cellular mechanisms that control APP alpha-secretase cleavage and Abeta generation. To explore the contributory pathways, we carried out an expression cloning screen. We identified a novel member of the sorting nexin (SNX) family of endosomal trafficking proteins, called SNX33, as a new activator of APP alpha-secretase cleavage. SNX33 is a homolog of SNX9 and was found to be a ubiquitously expressed phosphoprotein. Exogenous expression of SNX33 in cultured cells increased APP alpha-secretase cleavage 4-fold but surprisingly had little effect on beta-secretase cleavage. This effect was similar to the expression of the dominant negative dynamin-1 mutant K44A. SNX33 bound the endocytic GTPase dynamin and reduced the rate of APP endocytosis in a dynamin-dependent manner. This led to an increase of APP at the plasma membrane, where alpha-secretase cleavage mostly occurs. In summary, our study identifies SNX33 as a new endocytic protein, which modulates APP endocytosis and APP alpha-secretase cleavage, and demonstrates that the rate of APP endocytosis is a major control factor for APP alpha-secretase cleavage.
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Affiliation(s)
- Susanne Schöbel
- Center for Integrated Protein Science and the Adolf-Butenandt-Institut, Ludwig Maximilians University, Munich, Germany
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