1
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Jalil S, Keskinen T, Juutila J, Sartori Maldonado R, Euro L, Suomalainen A, Lapatto R, Kuuluvainen E, Hietakangas V, Otonkoski T, Hyvönen ME, Wartiovaara K. Genetic and functional correction of argininosuccinate lyase deficiency using CRISPR adenine base editors. Am J Hum Genet 2024; 111:714-728. [PMID: 38579669 PMCID: PMC11023919 DOI: 10.1016/j.ajhg.2024.03.004] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 03/06/2024] [Accepted: 03/06/2024] [Indexed: 04/07/2024] Open
Abstract
Argininosuccinate lyase deficiency (ASLD) is a recessive metabolic disorder caused by variants in ASL. In an essential step in urea synthesis, ASL breaks down argininosuccinate (ASA), a pathognomonic ASLD biomarker. The severe disease forms lead to hyperammonemia, neurological injury, and even early death. The current treatments are unsatisfactory, involving a strict low-protein diet, arginine supplementation, nitrogen scavenging, and in some cases, liver transplantation. An unmet need exists for improved, efficient therapies. Here, we show the potential of a lipid nanoparticle-mediated CRISPR approach using adenine base editors (ABEs) for ASLD treatment. To model ASLD, we first generated human-induced pluripotent stem cells (hiPSCs) from biopsies of individuals homozygous for the Finnish founder variant (c.1153C>T [p.Arg385Cys]) and edited this variant using the ABE. We then differentiated the hiPSCs into hepatocyte-like cells that showed a 1,000-fold decrease in ASA levels compared to those of isogenic non-edited cells. Lastly, we tested three different FDA-approved lipid nanoparticle formulations to deliver the ABE-encoding RNA and the sgRNA targeting the ASL variant. This approach efficiently edited the ASL variant in fibroblasts with no apparent cell toxicity and minimal off-target effects. Further, the treatment resulted in a significant decrease in ASA, to levels of healthy donors, indicating restoration of the urea cycle. Our work describes a highly efficient approach to editing the disease-causing ASL variant and restoring the function of the urea cycle. This method relies on RNA delivered by lipid nanoparticles, which is compatible with clinical applications, improves its safety profile, and allows for scalable production.
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Affiliation(s)
- Sami Jalil
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Timo Keskinen
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Juhana Juutila
- Faculty of Biological and Environmental Sciences University of Helsinki, Helsinki, Finland; Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Rocio Sartori Maldonado
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Liliya Euro
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Anu Suomalainen
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Risto Lapatto
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland; New Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Emilia Kuuluvainen
- Faculty of Biological and Environmental Sciences University of Helsinki, Helsinki, Finland; Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Ville Hietakangas
- Faculty of Biological and Environmental Sciences University of Helsinki, Helsinki, Finland; Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Timo Otonkoski
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland; New Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Mervi E Hyvönen
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland; New Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Kirmo Wartiovaara
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland; Clinical Genetics, Helsinki University Hospital, Helsinki, Finland.
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2
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Mattila J, Viitanen A, Fabris G, Strutynska T, Korzelius J, Hietakangas V. Stem cell mTOR signaling directs region-specific cell fate decisions during intestinal nutrient adaptation. Sci Adv 2024; 10:eadi2671. [PMID: 38335286 PMCID: PMC10857434 DOI: 10.1126/sciadv.adi2671] [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] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 01/09/2024] [Indexed: 02/12/2024]
Abstract
The adult intestine is a regionalized organ, whose size and cellular composition are adjusted in response to nutrient status. This involves dynamic regulation of intestinal stem cell (ISC) proliferation and differentiation. How nutrient signaling controls cell fate decisions to drive regional changes in cell-type composition remains unclear. Here, we show that intestinal nutrient adaptation involves region-specific control of cell size, cell number, and differentiation. We uncovered that activation of mTOR complex 1 (mTORC1) increases ISC size in a region-specific manner. mTORC1 activity promotes Delta expression to direct cell fate toward the absorptive enteroblast lineage while inhibiting secretory enteroendocrine cell differentiation. In aged flies, the ISC mTORC1 signaling is deregulated, being constitutively high and unresponsive to diet, which can be mitigated through lifelong intermittent fasting. In conclusion, mTORC1 signaling contributes to the ISC fate decision, enabling regional control of intestinal cell differentiation in response to nutrition.
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Affiliation(s)
- Jaakko Mattila
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki 00790, Finland
| | - Arto Viitanen
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki 00790, Finland
- Institute of Biotechnology, University of Helsinki, Helsinki 00790, Finland
| | - Gaia Fabris
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki 00790, Finland
- Institute of Biotechnology, University of Helsinki, Helsinki 00790, Finland
| | - Tetiana Strutynska
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki 00790, Finland
| | - Jerome Korzelius
- School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
| | - Ville Hietakangas
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki 00790, Finland
- Institute of Biotechnology, University of Helsinki, Helsinki 00790, Finland
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3
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Paukštytė J, López Cabezas RM, Feng Y, Tong K, Schnyder D, Elomaa E, Gregorova P, Doudin M, Särkkä M, Sarameri J, Lippi A, Vihinen H, Juutila J, Nieminen A, Törönen P, Holm L, Jokitalo E, Krisko A, Huiskonen J, Sarin LP, Hietakangas V, Picotti P, Barral Y, Saarikangas J. Global analysis of aging-related protein structural changes uncovers enzyme-polymerization-based control of longevity. Mol Cell 2023; 83:3360-3376.e11. [PMID: 37699397 DOI: 10.1016/j.molcel.2023.08.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [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: 10/19/2022] [Revised: 05/18/2023] [Accepted: 08/11/2023] [Indexed: 09/14/2023]
Abstract
Aging is associated with progressive phenotypic changes. Virtually all cellular phenotypes are produced by proteins, and their structural alterations can lead to age-related diseases. However, we still lack comprehensive knowledge of proteins undergoing structural-functional changes during cellular aging and their contributions to age-related phenotypes. Here, we conducted proteome-wide analysis of early age-related protein structural changes in budding yeast using limited proteolysis-mass spectrometry (LiP-MS). The results, compiled in online ProtAge catalog, unraveled age-related functional changes in regulators of translation, protein folding, and amino acid metabolism. Mechanistically, we found that folded glutamate synthase Glt1 polymerizes into supramolecular self-assemblies during aging, causing breakdown of cellular amino acid homeostasis. Inhibiting Glt1 polymerization by mutating the polymerization interface restored amino acid levels in aged cells, attenuated mitochondrial dysfunction, and led to lifespan extension. Altogether, this comprehensive map of protein structural changes enables identifying mechanisms of age-related phenotypes and offers opportunities for their reversal.
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Affiliation(s)
- Jurgita Paukštytė
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, 00790 Helsinki, Finland; Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland
| | - Rosa María López Cabezas
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, 00790 Helsinki, Finland; Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland
| | - Yuehan Feng
- Institute of Biochemistry, ETH Zurich, 8093 Zurich, Switzerland
| | - Kai Tong
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, 00790 Helsinki, Finland; Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland; School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA; Interdisciplinary Graduate Program in Quantitative Biosciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | | | - Ellinoora Elomaa
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, 00790 Helsinki, Finland; Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland
| | - Pavlina Gregorova
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland
| | - Matteo Doudin
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, 00790 Helsinki, Finland; Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland
| | - Meeri Särkkä
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, 00790 Helsinki, Finland; Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland
| | - Jesse Sarameri
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, 00790 Helsinki, Finland; Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland
| | - Alice Lippi
- Department of Experimental Neurodegeneration, University Medical Center Göttingen, 37075 Göttingen, Germany
| | - Helena Vihinen
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00790 Helsinki, Finland
| | - Juhana Juutila
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, HiLIFE, University of Helsinki, 00790 Helsinki, Finland
| | - Anni Nieminen
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, HiLIFE, University of Helsinki, 00790 Helsinki, Finland
| | - Petri Törönen
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, HiLIFE, University of Helsinki, 00790 Helsinki, Finland
| | - Liisa Holm
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, HiLIFE, University of Helsinki, 00790 Helsinki, Finland
| | - Eija Jokitalo
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00790 Helsinki, Finland
| | - Anita Krisko
- Department of Experimental Neurodegeneration, University Medical Center Göttingen, 37075 Göttingen, Germany
| | - Juha Huiskonen
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00790 Helsinki, Finland
| | - L Peter Sarin
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland
| | - Ville Hietakangas
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, HiLIFE, University of Helsinki, 00790 Helsinki, Finland
| | - Paola Picotti
- Institute of Biochemistry, ETH Zurich, 8093 Zurich, Switzerland; Institute of Molecular Systems Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Yves Barral
- Institute of Biochemistry, ETH Zurich, 8093 Zurich, Switzerland
| | - Juha Saarikangas
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, 00790 Helsinki, Finland; Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland.
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4
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Rönkkö J, Rodriguez Y, Rasila T, Torregrosa-Muñumer R, Pennonen J, Kvist J, Kuuluvainen E, Bosch LVD, Hietakangas V, Bultynck G, Tyynismaa H, Ylikallio E. Human IP 3 receptor triple knockout stem cells remain pluripotent despite altered mitochondrial metabolism. Cell Calcium 2023; 114:102782. [PMID: 37481871 DOI: 10.1016/j.ceca.2023.102782] [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: 04/25/2023] [Revised: 06/14/2023] [Accepted: 07/13/2023] [Indexed: 07/25/2023]
Abstract
Inositol 1,4,5-trisphosphate receptors (IP3Rs) are ER Ca2+-release channels that control a broad set of cellular processes. Animal models lacking IP3Rs in different combinations display severe developmental phenotypes. Given the importance of IP3Rs in human diseases, we investigated their role in human induced pluripotent stem cells (hiPSC) by developing single IP3R and triple IP3R knockouts (TKO). Genome edited TKO-hiPSC lacking all three IP3R isoforms, IP3R1, IP3R2, IP3R3, failed to generate Ca2+ signals in response to agonists activating GPCRs, but retained stemness and pluripotency. Steady state metabolite profiling and flux analysis of TKO-hiPSC indicated distinct alterations in tricarboxylic acid cycle metabolites consistent with a deficiency in their pyruvate utilization via pyruvate dehydrogenase, shifting towards pyruvate carboxylase pathway. These results demonstrate that IP3Rs are not essential for hiPSC identity and pluripotency but regulate mitochondrial metabolism. This set of knockout hiPSC is a valuable resource for investigating IP3Rs in human cell types of interest.
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Affiliation(s)
- Julius Rönkkö
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, 00290, Finland
| | - Yago Rodriguez
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, 00290, Finland
| | - Tiina Rasila
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, 00290, Finland
| | - Rubén Torregrosa-Muñumer
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, 00290, Finland
| | - Jana Pennonen
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, 00290, Finland
| | - Jouni Kvist
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, 00290, Finland
| | - Emilia Kuuluvainen
- Molecular and Integrative Bioscience Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, 00790, Finland; Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, 00790, Finland
| | - Ludo Van Den Bosch
- Department of Neurosciences, Experimental Neurology and Leuven Brain Institute, KU Leuven - University of Leuven, 3000, Leuven, Belgium; VIB Center for Brain & Disease Research, Laboratory of Neurobiology, 3000, Leuven, Belgium
| | - Ville Hietakangas
- Molecular and Integrative Bioscience Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, 00790, Finland; Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, 00790, Finland
| | - Geert Bultynck
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine & Leuven Kanker Instituut, Leuven, 3000, Belgium
| | - Henna Tyynismaa
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, 00290, Finland
| | - Emil Ylikallio
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, 00290, Finland; Clinical Neurosciences, Neurology, University of Helsinki and Helsinki University Hospital, Helsinki, 00290, Finland.
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5
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Barsby T, Vähäkangas E, Ustinov J, Montaser H, Ibrahim H, Lithovius V, Kuuluvainen E, Chandra V, Saarimäki-Vire J, Katajisto P, Hietakangas V, Otonkoski T. Aberrant metabolite trafficking and fuel sensitivity in human pluripotent stem cell-derived islets. Cell Rep 2023; 42:112970. [PMID: 37556323 DOI: 10.1016/j.celrep.2023.112970] [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: 02/27/2023] [Revised: 06/09/2023] [Accepted: 07/26/2023] [Indexed: 08/11/2023] Open
Abstract
Pancreatic islets regulate blood glucose homeostasis through the controlled release of insulin; however, current metabolic models of glucose-sensitive insulin secretion are incomplete. A comprehensive understanding of islet metabolism is integral to studies of endocrine cell development as well as diabetic islet dysfunction. Human pluripotent stem cell-derived islets (SC-islets) are a developmentally relevant model of human islet function that have great potential in providing a cure for type 1 diabetes. Using multiple 13C-labeled metabolic fuels, we demonstrate that SC-islets show numerous divergent patterns of metabolite trafficking in proposed insulin release pathways compared with primary human islets but are still reliant on mitochondrial aerobic metabolism to derive function. Furthermore, reductive tricarboxylic acid cycle activity and glycolytic metabolite cycling occur in SC-islets, suggesting that non-canonical coupling factors are also present. In aggregate, we show that many facets of SC-islet metabolism overlap with those of primary islets, albeit with a retained immature signature.
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Affiliation(s)
- Tom Barsby
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland.
| | - Eliisa Vähäkangas
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Jarkko Ustinov
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Hossam Montaser
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Hazem Ibrahim
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Väinö Lithovius
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Emilia Kuuluvainen
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Vikash Chandra
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Jonna Saarimäki-Vire
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Pekka Katajisto
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Ville Hietakangas
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Timo Otonkoski
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland; Children's Hospital, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.
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6
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van den Berg L, Kokki K, Wowro SJ, Petricek KM, Deniz O, Stegmann CA, Robciuc M, Teesalu M, Melvin RG, Nieminen AI, Schupp M, Hietakangas V. Sugar-responsive inhibition of Myc-dependent ribosome biogenesis by Clockwork orange. Cell Rep 2023; 42:112739. [PMID: 37405919 DOI: 10.1016/j.celrep.2023.112739] [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: 07/01/2022] [Revised: 05/25/2023] [Accepted: 06/19/2023] [Indexed: 07/07/2023] Open
Abstract
The ability to feed on a sugar-containing diet depends on a gene regulatory network controlled by the intracellular sugar sensor Mondo/ChREBP-Mlx, which remains insufficiently characterized. Here, we present a genome-wide temporal clustering of sugar-responsive gene expression in Drosophila larvae. We identify gene expression programs responding to sugar feeding, including downregulation of ribosome biogenesis genes, known targets of Myc. Clockwork orange (CWO), a component of the circadian clock, is found to be a mediator of this repressive response and to be necessary for survival on a high-sugar diet. CWO expression is directly activated by Mondo-Mlx, and it counteracts Myc through repression of its gene expression and through binding to overlapping genomic regions. CWO mouse ortholog BHLHE41 has a conserved role in repressing ribosome biogenesis genes in primary hepatocytes. Collectively, our data uncover a cross-talk between conserved gene regulatory circuits balancing the activities of anabolic pathways to maintain homeostasis during sugar feeding.
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Affiliation(s)
- Linda van den Berg
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, 00790 Helsinki, Finland
| | - Krista Kokki
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, 00790 Helsinki, Finland
| | - Sylvia J Wowro
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Pharmacology, Max Rubner Center (MRC) for Cardiovascular Metabolic Renal Research, 10117 Berlin, Germany
| | - Konstantin M Petricek
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Pharmacology, Max Rubner Center (MRC) for Cardiovascular Metabolic Renal Research, 10117 Berlin, Germany
| | - Onur Deniz
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, 00790 Helsinki, Finland
| | - Catrin A Stegmann
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Pharmacology, Max Rubner Center (MRC) for Cardiovascular Metabolic Renal Research, 10117 Berlin, Germany
| | - Marius Robciuc
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, 00790 Helsinki, Finland
| | - Mari Teesalu
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, 00790 Helsinki, Finland
| | - Richard G Melvin
- School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, VIC 3083, Australia
| | - Anni I Nieminen
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, 00790 Helsinki, Finland
| | - Michael Schupp
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Pharmacology, Max Rubner Center (MRC) for Cardiovascular Metabolic Renal Research, 10117 Berlin, Germany
| | - Ville Hietakangas
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, 00790 Helsinki, Finland.
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7
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Deniz O, Hasygar K, Hietakangas V. Cellular and physiological roles of the conserved atypical MAP kinase ERK7. FEBS Lett 2023; 597:601-607. [PMID: 36266944 DOI: 10.1002/1873-3468.14521] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 09/20/2022] [Accepted: 10/12/2022] [Indexed: 11/10/2022]
Abstract
Extracellular signal-regulated kinase 7 (ERK7), also known as ERK8 and MAPK15, is an atypical member of the MAP kinase family. Compared with other MAP kinases, the biological roles of ERK7 remain poorly understood. Recent work, however, has revealed several novel functions for ERK7. These include a highly conserved essential role in ciliogenesis, the ability to control cell growth, metabolism and autophagy, as well as the maintenance of genomic integrity. ERK7 functions through phosphorylation-dependent and -independent mechanisms and it is activated by cellular stressors, including DNA-damaging agents, and nutrient deprivation. Here, we summarize recent developments in understanding ERK7 function, emphasizing its conserved roles in cellular and physiological regulation.
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Affiliation(s)
- Onur Deniz
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Finland
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Finland
| | - Kiran Hasygar
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Finland
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Finland
| | - Ville Hietakangas
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Finland
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Finland
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8
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Balboa D, Barsby T, Lithovius V, Saarimäki-Vire J, Omar-Hmeadi M, Dyachok O, Montaser H, Lund PE, Yang M, Ibrahim H, Näätänen A, Chandra V, Vihinen H, Jokitalo E, Kvist J, Ustinov J, Nieminen AI, Kuuluvainen E, Hietakangas V, Katajisto P, Lau J, Carlsson PO, Barg S, Tengholm A, Otonkoski T. Functional, metabolic and transcriptional maturation of human pancreatic islets derived from stem cells. Nat Biotechnol 2022; 40:1042-1055. [PMID: 35241836 PMCID: PMC9287162 DOI: 10.1038/s41587-022-01219-z] [Citation(s) in RCA: 102] [Impact Index Per Article: 51.0] [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: 03/18/2021] [Accepted: 01/11/2022] [Indexed: 12/19/2022]
Abstract
Transplantation of pancreatic islet cells derived from human pluripotent stem cells is a promising treatment for diabetes. Despite progress in the generation of stem-cell-derived islets (SC-islets), no detailed characterization of their functional properties has been conducted. Here, we generated functionally mature SC-islets using an optimized protocol and benchmarked them comprehensively against primary adult islets. Biphasic glucose-stimulated insulin secretion developed during in vitro maturation, associated with cytoarchitectural reorganization and the increasing presence of alpha cells. Electrophysiology, signaling and exocytosis of SC-islets were similar to those of adult islets. Glucose-responsive insulin secretion was achieved despite differences in glycolytic and mitochondrial glucose metabolism. Single-cell transcriptomics of SC-islets in vitro and throughout 6 months of engraftment in mice revealed a continuous maturation trajectory culminating in a transcriptional landscape closely resembling that of primary islets. Our thorough evaluation of SC-islet maturation highlights their advanced degree of functionality and supports their use in further efforts to understand and combat diabetes. Pancreatic islets derived from stem cells are benchmarked against primary cells.
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Affiliation(s)
- Diego Balboa
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland.,Bioinformatics and Genomics Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain.,Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Barcelona, Spain
| | - Tom Barsby
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Väinö Lithovius
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Jonna Saarimäki-Vire
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | | | - Oleg Dyachok
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Hossam Montaser
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Per-Eric Lund
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Mingyu Yang
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Hazem Ibrahim
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Anna Näätänen
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Vikash Chandra
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Helena Vihinen
- Electron Microscopy Unit, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Eija Jokitalo
- Electron Microscopy Unit, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Jouni Kvist
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Jarkko Ustinov
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Anni I Nieminen
- Metabolomics Unit, Institute for Molecular Medicine Finland, Helsinki, Finland
| | - Emilia Kuuluvainen
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Ville Hietakangas
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland.,Molecular and Integrative Bioscience Research Program, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Pekka Katajisto
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland.,Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Joey Lau
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Per-Ola Carlsson
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Sebastian Barg
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Anders Tengholm
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Timo Otonkoski
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland. .,Children's Hospital, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.
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9
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Döhla J, Kuuluvainen E, Gebert N, Amaral A, Englund JI, Gopalakrishnan S, Konovalova S, Nieminen AI, Salminen ES, Torregrosa Muñumer R, Ahlqvist K, Yang Y, Bui H, Otonkoski T, Käkelä R, Hietakangas V, Tyynismaa H, Ori A, Katajisto P. Metabolic determination of cell fate through selective inheritance of mitochondria. Nat Cell Biol 2022; 24:148-154. [PMID: 35165416 PMCID: PMC7612378 DOI: 10.1038/s41556-021-00837-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [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: 07/31/2018] [Accepted: 12/20/2021] [Indexed: 12/13/2022]
Abstract
Metabolic characteristics of adult stem cells are distinct from their differentiated progeny, and cellular metabolism is emerging as a potential driver of cell fate conversions1-4. How these metabolic features are established remains unclear. Here we identified inherited metabolism imposed by functionally distinct mitochondrial age-classes as a fate determinant in asymmetric division of epithelial stem-like cells. While chronologically old mitochondria support oxidative respiration, the electron transport chain of new organelles is proteomically immature and they respire less. After cell division, selectively segregated mitochondrial age-classes elicit a metabolic bias in progeny cells, with oxidative energy metabolism promoting differentiation in cells that inherit old mitochondria. Cells that inherit newly synthesized mitochondria with low levels of Rieske iron-sulfur polypeptide 1 have a higher pentose phosphate pathway activity, which promotes de novo purine biosynthesis and redox balance, and is required to maintain stemness during early fate determination after division. Our results demonstrate that fate decisions are susceptible to intrinsic metabolic bias imposed by selectively inherited mitochondria.
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Affiliation(s)
- Julia Döhla
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Emilia Kuuluvainen
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
| | - Nadja Gebert
- Leibniz Institute on Aging-Fritz Lipmann Institute (FLI), Jena, Germany
| | - Ana Amaral
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Johanna I Englund
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
| | | | - Svetlana Konovalova
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Anni I Nieminen
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Ella S Salminen
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
| | - Rubén Torregrosa Muñumer
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Kati Ahlqvist
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
| | - Yang Yang
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Hien Bui
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
| | - Timo Otonkoski
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Reijo Käkelä
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Ville Hietakangas
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Henna Tyynismaa
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Neuroscience Center, HiLIFE, University of Helsinki, Helsinki, Finland
| | - Alessandro Ori
- Leibniz Institute on Aging-Fritz Lipmann Institute (FLI), Jena, Germany
| | - Pekka Katajisto
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland.
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden.
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.
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10
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Kokki K, Lamichane N, Nieminen AI, Ruhanen H, Morikka J, Robciuc M, Rovenko BM, Havula E, Käkelä R, Hietakangas V. Metabolic gene regulation by Drosophila GATA transcription factor Grain. PLoS Genet 2021; 17:e1009855. [PMID: 34634038 PMCID: PMC8530363 DOI: 10.1371/journal.pgen.1009855] [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] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 10/21/2021] [Accepted: 10/01/2021] [Indexed: 11/18/2022] Open
Abstract
Nutrient-dependent gene regulation critically contributes to homeostatic control of animal physiology in changing nutrient landscape. In Drosophila, dietary sugars activate transcription factors (TFs), such as Mondo-Mlx, Sugarbabe and Cabut, which control metabolic gene expression to mediate physiological adaptation to high sugar diet. TFs that correspondingly control sugar responsive metabolic genes under conditions of low dietary sugar remain, however, poorly understood. Here we identify a role for Drosophila GATA TF Grain in metabolic gene regulation under both low and high sugar conditions. De novo motif prediction uncovered a significant over-representation of GATA-like motifs on the promoters of sugar-activated genes in Drosophila larvae, which are regulated by Grain, the fly ortholog of GATA1/2/3 subfamily. grain expression is activated by sugar in Mondo-Mlx-dependent manner and it contributes to sugar-responsive gene expression in the fat body. On the other hand, grain displays strong constitutive expression in the anterior midgut, where it drives lipogenic gene expression also under low sugar conditions. Consistently with these differential tissue-specific roles, Grain deficient larvae display delayed development on high sugar diet, while showing deregulated central carbon and lipid metabolism primarily on low sugar diet. Collectively, our study provides evidence for the role of a metazoan GATA transcription factor in nutrient-responsive metabolic gene regulation in vivo.
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Affiliation(s)
- Krista Kokki
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Nicole Lamichane
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Anni I. Nieminen
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Hanna Ruhanen
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
- Helsinki University Lipidomics Unit (HiLIPID), Helsinki Institute for Life Science (HiLIFE) and Biocenter Finland, Helsinki, Finland
| | - Jack Morikka
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Marius Robciuc
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Bohdana M. Rovenko
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Essi Havula
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Reijo Käkelä
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
- Helsinki University Lipidomics Unit (HiLIPID), Helsinki Institute for Life Science (HiLIFE) and Biocenter Finland, Helsinki, Finland
| | - Ville Hietakangas
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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11
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Viitanen A, Gullmets J, Morikka J, Katajisto P, Mattila J, Hietakangas V. An image analysis method for regionally defined cellular phenotyping of the Drosophila midgut. Cell Rep Methods 2021; 1:100059. [PMID: 35474669 PMCID: PMC9017226 DOI: 10.1016/j.crmeth.2021.100059] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 06/01/2021] [Accepted: 06/30/2021] [Indexed: 11/27/2022]
Abstract
The intestine is divided into functionally distinct regions along the anteroposterior (A/P) axis. How the regional identity influences the function of intestinal stem cells (ISCs) and their offspring remain largely unresolved. We introduce an imaging-based method, "Linear Analysis of Midgut" (LAM), which allows quantitative, regionally defined cellular phenotyping of the whole Drosophila midgut. LAM transforms image-derived cellular data from three-dimensional midguts into a linearized representation, binning it into segments along the A/P axis. Through automated multivariate determination of regional borders, LAM allows mapping and comparison of cellular features and frequencies with subregional resolution. Through the use of LAM, we quantify the distributions of ISCs, enteroblasts, and enteroendocrine cells in a steady-state midgut, and reveal unprecedented regional heterogeneity in the ISC response to a Drosophila model of colitis. Altogether, LAM is a powerful tool for organ-wide quantitative analysis of the regional heterogeneity of midgut cells.
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Affiliation(s)
- Arto Viitanen
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki 00790, Finland
- Institute of Biotechnology, University of Helsinki, Helsinki 00790, Finland
| | - Josef Gullmets
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki 00790, Finland
- Institute of Biotechnology, University of Helsinki, Helsinki 00790, Finland
| | - Jack Morikka
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki 00790, Finland
- Institute of Biotechnology, University of Helsinki, Helsinki 00790, Finland
| | - Pekka Katajisto
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki 00790, Finland
- Institute of Biotechnology, University of Helsinki, Helsinki 00790, Finland
| | - Jaakko Mattila
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki 00790, Finland
| | - Ville Hietakangas
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki 00790, Finland
- Institute of Biotechnology, University of Helsinki, Helsinki 00790, Finland
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12
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Flanagan DJ, Pentinmikko N, Luopajärvi K, Willis NJ, Gilroy K, Raven AP, Mcgarry L, Englund JI, Webb AT, Scharaw S, Nasreddin N, Hodder MC, Ridgway RA, Minnee E, Sphyris N, Gilchrist E, Najumudeen AK, Romagnolo B, Perret C, Williams AC, Clevers H, Nummela P, Lähde M, Alitalo K, Hietakangas V, Hedley A, Clark W, Nixon C, Kirschner K, Jones EY, Ristimäki A, Leedham SJ, Fish PV, Vincent JP, Katajisto P, Sansom OJ. NOTUM from Apc-mutant cells biases clonal competition to initiate cancer. Nature 2021; 594:430-435. [PMID: 34079124 PMCID: PMC7615049 DOI: 10.1038/s41586-021-03525-z] [Citation(s) in RCA: 91] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 04/07/2021] [Indexed: 02/06/2023]
Abstract
The tumour suppressor APC is the most commonly mutated gene in colorectal cancer. Loss of Apc in intestinal stem cells drives the formation of adenomas in mice via increased WNT signalling1, but reduced secretion of WNT ligands increases the ability of Apc-mutant intestinal stem cells to colonize a crypt (known as fixation)2. Here we investigated how Apc-mutant cells gain a clonal advantage over wild-type counterparts to achieve fixation. We found that Apc-mutant cells are enriched for transcripts that encode several secreted WNT antagonists, with Notum being the most highly expressed. Conditioned medium from Apc-mutant cells suppressed the growth of wild-type organoids in a NOTUM-dependent manner. Furthermore, NOTUM-secreting Apc-mutant clones actively inhibited the proliferation of surrounding wild-type crypt cells and drove their differentiation, thereby outcompeting crypt cells from the niche. Genetic or pharmacological inhibition of NOTUM abrogated the ability of Apc-mutant cells to expand and form intestinal adenomas. We identify NOTUM as a key mediator during the early stages of mutation fixation that can be targeted to restore wild-type cell competitiveness and provide preventative strategies for people at a high risk of developing colorectal cancer.
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Affiliation(s)
| | - Nalle Pentinmikko
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
- Molecular and Integrative Bioscience Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Kalle Luopajärvi
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
- Molecular and Integrative Bioscience Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Nicky J Willis
- Alzheimer's Research UK UCL Drug Discovery Institute, University College London, London, UK
| | - Kathryn Gilroy
- Cancer Research UK Beatson Institute, Glasgow, UK
- SpecifiCancer CRUK Grand Challenge Team (C7932/A29055), Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Alexander P Raven
- Cancer Research UK Beatson Institute, Glasgow, UK
- SpecifiCancer CRUK Grand Challenge Team (C7932/A29055), Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Lynn Mcgarry
- Cancer Research UK Beatson Institute, Glasgow, UK
| | - Johanna I Englund
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
- Molecular and Integrative Bioscience Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Anna T Webb
- Department of Cell and Molecular Biology (CMB), Karolinska Institutet, Stockholm, Sweden
| | - Sandra Scharaw
- Department of Cell and Molecular Biology (CMB), Karolinska Institutet, Stockholm, Sweden
| | - Nadia Nasreddin
- Intestinal Stem Cell Biology Lab, Wellcome Trust Centre Human Genetics, University of Oxford, Oxford, UK
| | - Michael C Hodder
- Cancer Research UK Beatson Institute, Glasgow, UK
- Institute of Cancer Sciences, University of Glasgow, Glasgow, UK
| | | | - Emma Minnee
- Cancer Research UK Beatson Institute, Glasgow, UK
- Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | | | - Ella Gilchrist
- Cancer Research UK Beatson Institute, Glasgow, UK
- Institute of Cancer Sciences, University of Glasgow, Glasgow, UK
| | | | | | - Christine Perret
- Université de Paris, Institut Cochin, INSERM, CNRS, Paris, France
| | - Ann C Williams
- Colorectal Tumour Biology Group, School of Cellular and Molecular Medicine, Faculty of Life Sciences, University of Bristol, Bristol, UK
| | - Hans Clevers
- SpecifiCancer CRUK Grand Challenge Team (C7932/A29055), Department of Genetics, Harvard Medical School, Boston, MA, USA
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences, Utrecht, The Netherlands
| | - Pirjo Nummela
- Department of Pathology, Applied Tumor Genomics, Research Programs Unit and HUSLAB, HUS Diagnostic Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Marianne Lähde
- Translational Cancer Medicine Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Wihuri Research Institute, University of Helsinki, Helsinki, Finland
| | - Kari Alitalo
- Translational Cancer Medicine Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Wihuri Research Institute, University of Helsinki, Helsinki, Finland
| | - Ville Hietakangas
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
- Molecular and Integrative Bioscience Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Ann Hedley
- Cancer Research UK Beatson Institute, Glasgow, UK
| | | | - Colin Nixon
- Cancer Research UK Beatson Institute, Glasgow, UK
| | | | - E Yvonne Jones
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Ari Ristimäki
- Department of Pathology, Applied Tumor Genomics, Research Programs Unit and HUSLAB, HUS Diagnostic Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Simon J Leedham
- Intestinal Stem Cell Biology Lab, Wellcome Trust Centre Human Genetics, University of Oxford, Oxford, UK
| | - Paul V Fish
- Alzheimer's Research UK UCL Drug Discovery Institute, University College London, London, UK
- The Francis Crick Institute, London, UK
| | | | - Pekka Katajisto
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland.
- Molecular and Integrative Bioscience Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.
- Department of Cell and Molecular Biology (CMB), Karolinska Institutet, Stockholm, Sweden.
| | - Owen J Sansom
- Cancer Research UK Beatson Institute, Glasgow, UK.
- SpecifiCancer CRUK Grand Challenge Team (C7932/A29055), Department of Genetics, Harvard Medical School, Boston, MA, USA.
- Institute of Cancer Sciences, University of Glasgow, Glasgow, UK.
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13
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Hasygar K, Deniz O, Liu Y, Gullmets J, Hynynen R, Ruhanen H, Kokki K, Käkelä R, Hietakangas V. Coordinated control of adiposity and growth by anti-anabolic kinase ERK7. EMBO Rep 2020; 22:e49602. [PMID: 33369866 PMCID: PMC7857433 DOI: 10.15252/embr.201949602] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 11/18/2020] [Accepted: 11/27/2020] [Indexed: 11/23/2022] Open
Abstract
Energy storage and growth are coordinated in response to nutrient status of animals. How nutrient‐regulated signaling pathways control these processes in vivo remains insufficiently understood. Here, we establish an atypical MAP kinase, ERK7, as an inhibitor of adiposity and growth in Drosophila. ERK7 mutant larvae display elevated triacylglycerol (TAG) stores and accelerated growth rate, while overexpressed ERK7 is sufficient to inhibit lipid storage and growth. ERK7 expression is elevated upon fasting and ERK7 mutant larvae display impaired survival during nutrient deprivation. ERK7 acts in the fat body, the insect counterpart of liver and adipose tissue, where it controls the subcellular localization of chromatin‐binding protein PWP1, a growth‐promoting downstream effector of mTOR. PWP1 maintains the expression of sugarbabe, encoding a lipogenic Gli‐similar family transcription factor. Both PWP1 and Sugarbabe are necessary for the increased growth and adiposity phenotypes of ERK7 loss‐of‐function animals. In conclusion, ERK7 is an anti‐anabolic kinase that inhibits lipid storage and growth while promoting survival on fasting conditions.
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Affiliation(s)
- Kiran Hasygar
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Onur Deniz
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Ying Liu
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Josef Gullmets
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Riikka Hynynen
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Hanna Ruhanen
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Helsinki University Lipidomics Unit (HiLIPID), Helsinki Institute for Life Science (HiLIFE) and Biocenter Finland, Helsinki, Finland
| | - Krista Kokki
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Reijo Käkelä
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Helsinki University Lipidomics Unit (HiLIPID), Helsinki Institute for Life Science (HiLIFE) and Biocenter Finland, Helsinki, Finland
| | - Ville Hietakangas
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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14
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Yalgin C, Rovenko B, Andjelković A, Neefjes M, Oymak B, Dufour E, Hietakangas V, Jacobs HT. Effects on Dopaminergic Neurons Are Secondary in COX-Deficient Locomotor Dysfunction in Drosophila. iScience 2020; 23:101362. [PMID: 32738610 PMCID: PMC7394922 DOI: 10.1016/j.isci.2020.101362] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [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: 05/08/2020] [Revised: 06/15/2020] [Accepted: 07/08/2020] [Indexed: 12/31/2022] Open
Abstract
Dopaminergic (DA) neurons have been implicated as key targets in neurological disorders, notably those involving locomotor impairment, and are considered to be highly vulnerable to mitochondrial dysfunction, a common feature of such diseases. Here we investigated a Drosophila model of locomotor disorders in which functional impairment is brought about by pan-neuronal RNAi knockdown of subunit COX7A of cytochrome oxidase (COX). Despite minimal neuronal loss by apoptosis, the expression and activity of tyrosine hydroxylase was decreased by half. Surprisingly, COX7A knockdown specifically targeted to DA neurons did not produce locomotor defect. Instead, using various drivers, we found that COX7A knockdown in specific groups of cholinergic and glutamatergic neurons underlay the phenotype. Based on our main finding, the vulnerability of DA neurons to mitochondrial dysfunction as a cause of impaired locomotion in other organisms, including mammals, warrants detailed investigation.
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Affiliation(s)
- Cagri Yalgin
- Faculty of Medicine and Health Technology, FI-33014 Tampere University, Finland; Institute of Biotechnology, FI-00014 University of Helsinki, Finland
| | - Bohdana Rovenko
- Institute of Biotechnology, FI-00014 University of Helsinki, Finland; Faculty of Biological and Environmental Sciences, FI-00014 University of Helsinki, Finland
| | - Ana Andjelković
- Faculty of Medicine and Health Technology, FI-33014 Tampere University, Finland
| | - Margot Neefjes
- Faculty of Medicine and Health Technology, FI-33014 Tampere University, Finland; Institute of Biotechnology, FI-00014 University of Helsinki, Finland
| | - Burak Oymak
- Institute of Biotechnology, FI-00014 University of Helsinki, Finland
| | - Eric Dufour
- Faculty of Medicine and Health Technology, FI-33014 Tampere University, Finland
| | - Ville Hietakangas
- Institute of Biotechnology, FI-00014 University of Helsinki, Finland; Faculty of Biological and Environmental Sciences, FI-00014 University of Helsinki, Finland
| | - Howard T Jacobs
- Faculty of Medicine and Health Technology, FI-33014 Tampere University, Finland.
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15
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Qiao X, Liu Y, Prada ML, Mohan AK, Gupta A, Jaiswal A, Sharma M, Merisaari J, Haikala HM, Talvinen K, Yetukuri L, Pylvänäinen JW, Klefström J, Kronqvist P, Meinander A, Aittokallio T, Hietakangas V, Eilers M, Westermarck J. UBR5 Is Coamplified with MYC in Breast Tumors and Encodes an Ubiquitin Ligase That Limits MYC-Dependent Apoptosis. Cancer Res 2020; 80:1414-1427. [PMID: 32029551 DOI: 10.1158/0008-5472.can-19-1647] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 11/21/2019] [Accepted: 01/28/2020] [Indexed: 11/16/2022]
Abstract
For maximal oncogenic activity, cellular MYC protein levels need to be tightly controlled so that they do not induce apoptosis. Here, we show how ubiquitin ligase UBR5 functions as a molecular rheostat to prevent excess accumulation of MYC protein. UBR5 ubiquitinates MYC and its effects on MYC protein stability are independent of FBXW7. Silencing of endogenous UBR5 induced MYC protein expression and regulated MYC target genes. Consistent with the tumor suppressor function of UBR5 (HYD) in Drosophila, HYD suppressed dMYC-dependent overgrowth of wing imaginal discs. In contrast, in cancer cells, UBR5 suppressed MYC-dependent priming to therapy-induced apoptosis. Of direct cancer relevance, MYC and UBR5 genes were coamplified in MYC-driven human cancers. Functionally, UBR5 suppressed MYC-mediated apoptosis in p53-mutant breast cancer cells with UBR5/MYC coamplification. Furthermore, single-cell immunofluorescence analysis demonstrated reciprocal expression of UBR5 and MYC in human basal-type breast cancer tissues. In summary, UBR5 is a novel MYC ubiquitin ligase and an endogenous rheostat for MYC activity. In MYC-amplified, and p53-mutant breast cancer cells, UBR5 has an important role in suppressing MYC-mediated apoptosis priming and in protection from drug-induced apoptosis. SIGNIFICANCE: These findings identify UBR5 as a novel MYC regulator, the inactivation of which could be very important for understanding of MYC dysregulation on cancer cells. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/7/1414/F1.large.jpg.
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Affiliation(s)
- Xi Qiao
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku, Finland.,Institute of Biomedicine, University of Turku, Turku, Finland.,TuDMM Doctoral Programme, University of Turku, Turku, Finland
| | - Ying Liu
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Maria Llamazares Prada
- Theodor Boveri Institute and Comprehensive Cancer Center, Mainfranken, Biocenter, University of Würzburg, Würzburg, Germany
| | - Aravind K Mohan
- Faculty of Science and Engineering, Cell Biology, Åbo Akademi University, Turku, Finland
| | - Abhishekh Gupta
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland
| | - Alok Jaiswal
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland
| | - Mukund Sharma
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku, Finland.,Institute of Biomedicine, University of Turku, Turku, Finland.,TuDMM Doctoral Programme, University of Turku, Turku, Finland
| | - Joni Merisaari
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku, Finland.,Institute of Biomedicine, University of Turku, Turku, Finland.,TuDMM Doctoral Programme, University of Turku, Turku, Finland
| | - Heidi M Haikala
- Research Programs Unit/Translational Cancer Medicine & HiLIFE, University of Helsinki, Helsinki, Finland
| | - Kati Talvinen
- Institute of Biomedicine, University of Turku, Turku, Finland
| | - Laxman Yetukuri
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku, Finland.,Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland
| | - Joanna W Pylvänäinen
- Turku BioImaging, University of Turku and Åbo Akademi University, Turku, Finland
| | - Juha Klefström
- Research Programs Unit/Translational Cancer Medicine & HiLIFE, University of Helsinki, Helsinki, Finland
| | | | - Annika Meinander
- Faculty of Science and Engineering, Cell Biology, Åbo Akademi University, Turku, Finland
| | - Tero Aittokallio
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland.,Department of Mathematics and Statistics, University of Turku, Turku, Finland
| | - Ville Hietakangas
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Martin Eilers
- Theodor Boveri Institute and Comprehensive Cancer Center, Mainfranken, Biocenter, University of Würzburg, Würzburg, Germany
| | - Jukka Westermarck
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku, Finland. .,Institute of Biomedicine, University of Turku, Turku, Finland
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16
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Melvin RG, Lamichane N, Havula E, Kokki K, Soeder C, Jones CD, Hietakangas V. Natural variation in sugar tolerance associates with changes in signaling and mitochondrial ribosome biogenesis. eLife 2018; 7:40841. [PMID: 30480548 PMCID: PMC6301794 DOI: 10.7554/elife.40841] [Citation(s) in RCA: 9] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 11/27/2018] [Indexed: 12/21/2022] Open
Abstract
How dietary selection affects genome evolution to define the optimal range of nutrient intake is a poorly understood question with medical relevance. We have addressed this question by analyzing Drosophila simulans and sechellia, recently diverged species with differential diet choice. D. sechellia larvae, specialized to a nutrient scarce diet, did not survive on sugar-rich conditions, while the generalist species D. simulans was sugar tolerant. Sugar tolerance in D. simulans was a tradeoff for performance on low-energy diet and was associated with global reprogramming of metabolic gene expression. Hybridization and phenotype-based introgression revealed the genomic regions of D. simulans that were sufficient for sugar tolerance. These regions included genes that are involved in mitochondrial ribosome biogenesis and intracellular signaling, such as PPP1R15/Gadd34 and SERCA, which contributed to sugar tolerance. In conclusion, genomic variation affecting genes involved in global metabolic control defines the optimal range for dietary macronutrient composition. Animals meet their nutritional needs in a variety of ways. Some animals are specialists feeding only on one type of food; others are generalists that can choose many different kinds of food depending on the situation. Despite these differences in diet, animals have similar needs for basic cellular metabolism. This suggests that generalist and specialist species likely process the foods they eat in different ways in order to meet their basic needs. For example, the metabolism of generalist species may be more flexible to adapt to changing food sources. To learn more about how metabolism evolves to respond to diet, scientists can study closely related species that eat different foods. For example, a species of fruit fly called Drosophila simulans is a generalist and its larvae can grow and develop by feeding on different kinds of decaying fruits and vegetables. Larvae of a closely related fruit fly called Drosophila sechellia are specialized to eat only the nutrient-poor Morinda fruit. Looking at how genetic differences between these species affect metabolism may provide scientists with clues about how these feeding strategies evolved. Melvin et al. grew larvae of D. sechellia and D. simulans in different conditions. D. sechellia larvae thrived in low nutrient conditions, but died when exposed to high sugar foods. By contrast, D. simulans larvae tolerated high sugar levels, but did poorly in low-nutrient conditions. Melvin et al. then bred the two species with each other, selecting flies that are genetically similar to D. sechellia but have the genes necessary for larvae to tolerate sugar. Analyzing the selected hybrid flies revealed genetic changes that explain the different survival abilities of each species. These changes suggest that D. sechellia rapidly evolved to thrive in low nutrient conditions, but the trade-off was losing their ability to tolerate high sugar levels. Overall, the results presented by Melvin et al. suggest that genetic adaptions to food sources can occur quickly and drastically change metabolism. Further research will be needed to confirm if similar metabolic trade-offs developed as part of human evolution. If so, human populations that survived with limited nutrition for many generations may have a harder time adapting to high-sugar modern diets.
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Affiliation(s)
- Richard G Melvin
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Nicole Lamichane
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Essi Havula
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Krista Kokki
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Charles Soeder
- Biology Department, The University of North Carolina at Chapel Hill, Carolina, United States
| | - Corbin D Jones
- Biology Department, The University of North Carolina at Chapel Hill, Carolina, United States
| | - Ville Hietakangas
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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17
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Abstract
PWP1 is a chromatin binding protein with an important role in animal growth control downstream of mTOR-mediated nutrient sensing. PWP1 has been shown to control tissue growth by promoting the transcription of 5.8S, 18S and 28S ribosomal RNAs (rRNAs) by RNA polymerase I (Pol I). Concomitantly with Pol I, RNA Polymerase III (Pol III) contributes to ribosome biogenesis by transcribing 5S rRNA in the nucleoplasm. Pol III activity is also closely controlled by nutrient-dependent signaling, however, how the activities of Pol I and Pol III are coordinated in response to nutrient-derived signals remains insufficiently understood. Experiments in Drosophila larvae and human cells reported here show that PWP1 associates with the chromatin at the 5S rDNA loci and is needed for nutrient-induced expression of 5S rRNA. Similar to the Pol I target rDNAs, PWP1 epigenetically maintains 5S rDNA in a transcription competent state. Thus, as a common regulator of Pol I and Pol III, PWP1 might contribute to coordinated control of ribosomal gene expression in response to nutrition. This article has an associated First Person interview with the first author of the paper. Summary: We report that a chromatin-binding protein PWP1 binds to 5S ribosomal DNA, regulates its epigenetic status and controls nutrient-dependent RNA polymerase III-mediated transcription of 5S ribosomal RNA.
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Affiliation(s)
- Ying Liu
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland.,Institute of Biotechnology, University of Helsinki, 00790 Helsinki, Finland
| | - Rita Cerejeira Matos
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland.,Institute of Biotechnology, University of Helsinki, 00790 Helsinki, Finland
| | - Tapio I Heino
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland
| | - Ville Hietakangas
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland .,Institute of Biotechnology, University of Helsinki, 00790 Helsinki, Finland
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18
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Sokolova M, Moore HM, Prajapati B, Dopie J, Meriläinen L, Honkanen M, Matos RC, Poukkula M, Hietakangas V, Vartiainen MK. Nuclear Actin Is Required for Transcription during Drosophila Oogenesis. iScience 2018; 9:63-70. [PMID: 30384134 PMCID: PMC6214840 DOI: 10.1016/j.isci.2018.10.010] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [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: 08/21/2018] [Revised: 09/28/2018] [Accepted: 10/10/2018] [Indexed: 01/30/2023] Open
Abstract
Actin has been linked to processes spanning the whole gene expression cascade, from regulating specific transcription factors, such as myocardin-related transcription factor, to chromatin remodeling and RNA polymerase function. However, whether actin controls the transcription of only specific genes or has a global role in gene expression has remained elusive. Our genome-wide analysis reveals, for the first time, that actin interacts with essentially all transcribed genes in Drosophila ovaries. Actin co-occupies the majority of gene promoters together with Pol II, and on highly expressed genes, these two proteins also associate with gene bodies. Mechanistically, actin is required for Pol II recruitment to gene bodies, and manipulation of nuclear transport factors for actin leads to the decreased expression of eggshell genes. Collectively, these results uncover a global role for actin in transcription and demonstrate the in vivo importance of balanced nucleocytoplasmic shuttling of actin in the transcriptional control of a developmental process. Genome-wide analysis shows actin on all transcribed genes Actin binds with RNA polymerase II near transcription start sites of most genes On highly expressed genes, actin is also found on the gene bodies Nuclear transport of actin is required for transcription during fly development
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Affiliation(s)
- Maria Sokolova
- Cell and Molecular Biology Program, Institute of Biotechnology, University of Helsinki, Viikinkaari 5, 00014 Helsinki, Finland
| | - Henna M Moore
- Cell and Molecular Biology Program, Institute of Biotechnology, University of Helsinki, Viikinkaari 5, 00014 Helsinki, Finland
| | - Bina Prajapati
- Cell and Molecular Biology Program, Institute of Biotechnology, University of Helsinki, Viikinkaari 5, 00014 Helsinki, Finland
| | - Joseph Dopie
- Cell and Molecular Biology Program, Institute of Biotechnology, University of Helsinki, Viikinkaari 5, 00014 Helsinki, Finland
| | - Leena Meriläinen
- Cell and Molecular Biology Program, Institute of Biotechnology, University of Helsinki, Viikinkaari 5, 00014 Helsinki, Finland
| | - Mikko Honkanen
- Cell and Molecular Biology Program, Institute of Biotechnology, University of Helsinki, Viikinkaari 5, 00014 Helsinki, Finland
| | - Rita Cerejeira Matos
- Cell and Molecular Biology Program, Institute of Biotechnology, University of Helsinki, Viikinkaari 5, 00014 Helsinki, Finland; Faculty of Biological and Environmental Sciences, University of Helsinki, Viikinkaari 9, 00014 Helsinki, Finland
| | - Minna Poukkula
- Cell and Molecular Biology Program, Institute of Biotechnology, University of Helsinki, Viikinkaari 5, 00014 Helsinki, Finland
| | - Ville Hietakangas
- Cell and Molecular Biology Program, Institute of Biotechnology, University of Helsinki, Viikinkaari 5, 00014 Helsinki, Finland; Faculty of Biological and Environmental Sciences, University of Helsinki, Viikinkaari 9, 00014 Helsinki, Finland
| | - Maria K Vartiainen
- Cell and Molecular Biology Program, Institute of Biotechnology, University of Helsinki, Viikinkaari 5, 00014 Helsinki, Finland.
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19
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Mattila J, Kokki K, Hietakangas V, Boutros M. Stem Cell Intrinsic Hexosamine Metabolism Regulates Intestinal Adaptation to Nutrient Content. Dev Cell 2018; 47:112-121.e3. [PMID: 30220570 PMCID: PMC6179903 DOI: 10.1016/j.devcel.2018.08.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 07/07/2018] [Accepted: 08/14/2018] [Indexed: 02/08/2023]
Abstract
The intestine is an organ with an exceptionally high rate of cell turnover, and perturbations in this process can lead to severe diseases such as cancer or intestinal atrophy. Nutrition has a profound impact on intestinal volume and cellular architecture. However, how intestinal homeostasis is maintained in fluctuating dietary conditions remains insufficiently understood. By utilizing the Drosophila midgut model, we reveal a novel stem cell intrinsic mechanism coupling cellular metabolism with stem cell extrinsic growth signal. Our results show that intestinal stem cells (ISCs) employ the hexosamine biosynthesis pathway (HBP) to monitor nutritional status. Elevated activity of HBP promotes Warburg effect-like metabolic reprogramming required for adjusting the ISC division rate according to nutrient content. Furthermore, HBP activity is an essential facilitator for insulin signaling-induced ISC proliferation. In conclusion, ISC intrinsic hexosamine synthesis regulates metabolic pathway activities and defines the stem cell responsiveness to niche-derived growth signals. HBP is a mediator of Drosophila midgut adaptation to nutrient content ISC intrinsic HBP is a necessary and sufficient driver of stem cell divisions HBP activity regulates a Warburg-like metabolic reprogramming of the intestine HBP activity determines the output of InR signaling of the ISCs
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Affiliation(s)
- Jaakko Mattila
- German Cancer Research Center, Division of Signaling and Functional Genomics and Heidelberg University, Heidelberg 69120, Germany
| | - Krista Kokki
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki 00790, Finland; Institute of Biotechnology, University of Helsinki, Helsinki 00790, Finland
| | - Ville Hietakangas
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki 00790, Finland; Institute of Biotechnology, University of Helsinki, Helsinki 00790, Finland
| | - Michael Boutros
- German Cancer Research Center, Division of Signaling and Functional Genomics and Heidelberg University, Heidelberg 69120, Germany.
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20
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Liu Y, Mattila J, Ventelä S, Yadav L, Zhang W, Lamichane N, Sundström J, Kauko O, Grénman R, Varjosalo M, Westermarck J, Hietakangas V. PWP1 Mediates Nutrient-Dependent Growth Control through Nucleolar Regulation of Ribosomal Gene Expression. Dev Cell 2017; 43:240-252.e5. [PMID: 29065309 DOI: 10.1016/j.devcel.2017.09.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [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: 06/16/2016] [Revised: 08/01/2017] [Accepted: 09/25/2017] [Indexed: 11/29/2022]
Abstract
Ribosome biogenesis regulates animal growth and is controlled by nutrient-responsive mTOR signaling. How ribosome biogenesis is regulated during the developmental growth of animals and how nutrient-responsive signaling adjusts ribosome biogenesis in this setting have remained insufficiently understood. We uncover PWP1 as a chromatin-associated regulator of developmental growth with a conserved role in RNA polymerase I (Pol I)-mediated rRNA transcription. We further observed that PWP1 epigenetically maintains the rDNA loci in a transcription-competent state. PWP1 responds to nutrition in Drosophila larvae via mTOR signaling through gene expression and phosphorylation, which controls the nucleolar localization of dPWP1. Our data further imply that dPWP1 acts synergistically with mTOR signaling to regulate the nucleolar localization of TFIIH, a known elongation factor of Pol I. Ribosome biogenesis is often deregulated in cancer, and we demonstrate that high PWP1 levels in human head and neck squamous cell carcinoma tumors are associated with poor prognosis.
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Affiliation(s)
- Ying Liu
- Department of Biosciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, University of Helsinki, 00790 Helsinki, Finland
| | - Jaakko Mattila
- Department of Biosciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, University of Helsinki, 00790 Helsinki, Finland
| | - Sami Ventelä
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland
| | - Leena Yadav
- Institute of Biotechnology, University of Helsinki, 00790 Helsinki, Finland
| | - Wei Zhang
- Department of Biosciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, University of Helsinki, 00790 Helsinki, Finland
| | - Nicole Lamichane
- Department of Biosciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, University of Helsinki, 00790 Helsinki, Finland
| | - Jari Sundström
- Department of Pathology, University of Turku, 20520 Turku, Finland; Department of Pathology, Turku University Hospital, 20521 Turku, Finland
| | - Otto Kauko
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland; Department of Pathology, University of Turku, 20520 Turku, Finland
| | - Reidar Grénman
- Department of Otorhinolaryngology - Head and Neck Surgery and Department of Medical Biochemistry and Genetics, University of Turku and Turku University Hospital, 20521 Turku, Finland
| | - Markku Varjosalo
- Institute of Biotechnology, University of Helsinki, 00790 Helsinki, Finland
| | - Jukka Westermarck
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland; Department of Pathology, University of Turku, 20520 Turku, Finland
| | - Ville Hietakangas
- Department of Biosciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, University of Helsinki, 00790 Helsinki, Finland.
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21
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Verardo LL, Sevón-Aimonen ML, Serenius T, Hietakangas V, Uimari P. Whole-genome association analysis of pork meat pH revealed three significant regions and several potential genes in Finnish Yorkshire pigs. BMC Genet 2017; 18:13. [PMID: 28193157 PMCID: PMC5307873 DOI: 10.1186/s12863-017-0482-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [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: 11/23/2016] [Accepted: 02/07/2017] [Indexed: 12/11/2022] Open
Abstract
Background One of the most commonly used quality measurements of pork is pH measured 24 h after slaughter. The most probable mode of inheritance for this trait is oligogenic with several known major genes, such as PRKAG3. In this study, we used whole-genome SNP genotypes of over 700 AI boars; after a quality check, 42,385 SNPs remained for association analysis. All the boars were purebred Finnish Yorkshire. To account for relatedness of the animals, a pedigree-based relationship matrix was used in a mixed linear model to test the effect of SNPs on pH measured from loin. A bioinformatics analysis was performed to identify the most promising genes in the significant regions related to meat quality. Results Genome-wide association study (GWAS) revealed three significant chromosomal regions: one on chromosome 3 (39.9 Mb–40.1 Mb) and two on chromosome 15 (58.5 Mb–60.5 Mb and 132 Mb–135 Mb including PRKAG3). A conditional analysis with a significant SNP in the PRKAG3 region, MARC0083357, as a covariate in the model retained the significant SNPs on chromosome 3. Even though linkage disequilibrium was relatively high over a long distance between MARC0083357 and other significant SNPs on chromosome 15, some SNPs retained their significance in the conditional analysis, even in the vicinity of PRKAG3. The significant regions harbored several genes, including two genes involved in cyclic AMP (cAMP) signaling: ADCY9 and CREBBP. Based on functional and transcription factor-gene networks, the most promising candidate genes for meat pH are ADCY9, CREBBP, TRAP1, NRG1, PRKAG3, VIL1, TNS1, and IGFBP5, and the key transcription factors related to these genes are HNF4A, PPARG, and Nkx2-5. Conclusions Based on SNP association, pathway, and transcription factor analysis, we were able to identify several genes with potential to control muscle cell homeostasis and meat quality. The associated SNPs can be used in selection for better pork. We also showed that post-GWAS analysis reveals important information about the genes’ potential role on meat quality. The gained information can be used in later functional studies.
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Affiliation(s)
- Lucas L Verardo
- Department of Animal Science/Animal Breeding, Federal University of Viçosa, Viçosa, Brazil
| | | | | | - Ville Hietakangas
- Department of Biosciences, University of Helsinki, Helsinki, Finland.,Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Pekka Uimari
- Department of Agricultural Sciences, University of Helsinki, Helsinki, Finland.
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22
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Chng WBA, Hietakangas V, Lemaitre B. Physiological Adaptations to Sugar Intake: New Paradigms from Drosophila melanogaster. Trends Endocrinol Metab 2017; 28:131-142. [PMID: 27923532 DOI: 10.1016/j.tem.2016.11.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 10/30/2016] [Accepted: 11/07/2016] [Indexed: 11/20/2022]
Abstract
Sugars are important energy sources, but high sugar intake poses a metabolic challenge and leads to diseases. Drosophila melanogaster is a generalist fruit breeder that encounters high levels of dietary sugars in its natural habitat. Consequently, Drosophila displays adaptive responses to dietary sugars, including highly conserved and unique metabolic adaptations not described in mammals. Carbohydrate homeostasis is maintained by a network comprising intracellular energy sensors, transcriptional regulators, and hormonal and neuronal mechanisms that together coordinate animal behavior, gut function, and metabolic flux. Here we give an overview of the physiological responses associated with sugar intake and discuss some of the emerging themes and applications of the Drosophila model in understanding sugar sensing and carbohydrate metabolism.
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Affiliation(s)
- Wen-Bin Alfred Chng
- Global Health Institute, School of Life Sciences, EPFL, Station 19, 1015 Lausanne, Switzerland.
| | - Ville Hietakangas
- Department of Biosciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, University of Helsinki, 00790 Helsinki, Finland
| | - Bruno Lemaitre
- Global Health Institute, School of Life Sciences, EPFL, Station 19, 1015 Lausanne, Switzerland.
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23
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Teesalu M, Rovenko BM, Hietakangas V. Salt-Inducible Kinase 3 Provides Sugar Tolerance by Regulating NADPH/NADP + Redox Balance. Curr Biol 2017; 27:458-464. [PMID: 28132818 DOI: 10.1016/j.cub.2016.12.032] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 11/21/2016] [Accepted: 12/13/2016] [Indexed: 12/13/2022]
Abstract
Nutrient-sensing pathways respond to changes in the levels of macronutrients, such as sugars, lipids, or amino acids, and regulate metabolic pathways to maintain organismal homeostasis [1, 2]. Consequently, nutrient sensing provides animals with the metabolic flexibility necessary for enduring temporal fluctuations in nutrient intake. Recent studies have shown that an animal's ability to survive on a high-sugar diet is determined by sugar-responsive gene regulation [3-8]. It remains to be elucidated whether other levels of metabolic control, such as post-translational regulation of metabolic enzymes, also contribute to organismal sugar tolerance. Furthermore, the sugar-regulated metabolic pathways contributing to sugar tolerance remain insufficiently characterized. Here, we identify Salt-inducible kinase 3 (SIK3), a member of the AMP-activated protein kinase (AMPK)-related kinase family, as a key determinant of Drosophila sugar tolerance. SIK3 allows sugar-feeding animals to increase the reductive capacity of nicotinamide adenine dinucleotide phosphate (NADPH/NADP+). NADPH mediates the reduction of the intracellular antioxidant glutathione, which is essential for survival on a high-sugar diet. SIK3 controls NADP+ reduction by phosphorylating and activating Glucose-6-phosphate dehydrogenase (G6PD), the rate-limiting enzyme of the pentose phosphate pathway. SIK3 gene expression is regulated by the sugar-regulated transcription factor complex Mondo-Mlx, which was previously identified as a key determinant of sugar tolerance. SIK3 converges with Mondo-Mlx in sugar-induced activation of G6PD, and simultaneous inhibition of SIK3 and Mondo-Mlx leads to strong synergistic lethality on a sugar-containing diet. In conclusion, SIK3 cooperates with Mondo-Mlx to maintain organismal sugar tolerance through the regulation of NADPH/NADP+ redox balance.
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Affiliation(s)
- Mari Teesalu
- Department of Biosciences, University of Helsinki, Viikinkaari 9, Helsinki 00014, Finland; Institute of Biotechnology, University of Helsinki, Viikinkaari 9, Helsinki 00014, Finland
| | - Bohdana M Rovenko
- Department of Biosciences, University of Helsinki, Viikinkaari 9, Helsinki 00014, Finland; Institute of Biotechnology, University of Helsinki, Viikinkaari 9, Helsinki 00014, Finland
| | - Ville Hietakangas
- Department of Biosciences, University of Helsinki, Viikinkaari 9, Helsinki 00014, Finland; Institute of Biotechnology, University of Helsinki, Viikinkaari 9, Helsinki 00014, Finland.
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24
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Fountain T, Melvin RG, Ikonen S, Ruokolainen A, Woestmann L, Hietakangas V, Hanski I. Oxygen and energy availability interact to determine flight performance in the Glanville fritillary butterfly. ACTA ACUST UNITED AC 2016; 219:1488-94. [PMID: 26944488 DOI: 10.1242/jeb.138180] [Citation(s) in RCA: 6] [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: 01/27/2016] [Accepted: 02/29/2016] [Indexed: 11/20/2022]
Abstract
Flying insects have the highest known mass-specific demand for oxygen, which makes it likely that reduced availability of oxygen might limit sustained flight, either instead of or in addition to the limitation due to metabolite resources. The Glanville fritillary butterfly (Melitaea cinxia) occurs as a large metapopulation in which adult butterflies frequently disperse between small local populations. Here, we examine how the interaction between oxygen availability and fuel use affects flight performance in the Glanville fritillary. Individuals were flown under either normoxic (21 kPa O2) or hypoxic (10 kPa O2) conditions and their flight metabolism was measured. To determine resource use, levels of circulating glucose, trehalose and whole-body triglyceride were recorded after flight. Flight performance was significantly reduced in hypoxic conditions. When flown under normoxic conditions, we observed a positive correlation among individuals between post-flight circulating trehalose levels and flight metabolic rate, suggesting that low levels of circulating trehalose constrains flight metabolism. To test this hypothesis experimentally, we measured the flight metabolic rate of individuals injected with a trehalase inhibitor. In support of the hypothesis, experimental butterflies showed significantly reduced flight metabolic rate, but not resting metabolic rate, in comparison to control individuals. By contrast, under hypoxia there was no relationship between trehalose and flight metabolic rate. Additionally, in this case, flight metabolic rate was reduced in spite of circulating trehalose levels that were high enough to support high flight metabolic rate under normoxic conditions. These results demonstrate a significant interaction between oxygen and energy availability for the control of flight performance.
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Affiliation(s)
- Toby Fountain
- Department of Biosciences, University of Helsinki, Helsinki 00014, Finland
| | - Richard G Melvin
- Department of Biosciences, University of Helsinki, Helsinki 00014, Finland
| | - Suvi Ikonen
- Lammi Biological Station, University of Helsinki, Lammi 16900, Finland
| | | | - Luisa Woestmann
- Department of Biosciences, University of Helsinki, Helsinki 00014, Finland
| | - Ville Hietakangas
- Department of Biosciences, University of Helsinki, Helsinki 00014, Finland
| | - Ilkka Hanski
- Department of Biosciences, University of Helsinki, Helsinki 00014, Finland
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25
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Mattila J, Havula E, Suominen E, Teesalu M, Surakka I, Hynynen R, Kilpinen H, Väänänen J, Hovatta I, Käkelä R, Ripatti S, Sandmann T, Hietakangas V. Mondo-Mlx Mediates Organismal Sugar Sensing through the Gli-Similar Transcription Factor Sugarbabe. Cell Rep 2015; 13:350-64. [PMID: 26440885 DOI: 10.1016/j.celrep.2015.08.081] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 08/02/2015] [Accepted: 08/31/2015] [Indexed: 01/23/2023] Open
Abstract
The ChREBP/Mondo-Mlx transcription factors are activated by sugars and are essential for sugar tolerance. They promote the conversion of sugars to lipids, but beyond this, their physiological roles are insufficiently understood. Here, we demonstrate that in an organism-wide setting in Drosophila, Mondo-Mlx controls the majority of sugar-regulated genes involved in nutrient digestion and transport as well as carbohydrate, amino acid, and lipid metabolism. Furthermore, human orthologs of the Mondo-Mlx targets display enrichment among gene variants associated with high circulating triglycerides. In addition to direct regulation of metabolic genes, Mondo-Mlx maintains metabolic homeostasis through downstream effectors, including the Activin ligand Dawdle and the Gli-similar transcription factor Sugarbabe. Sugarbabe controls a subset of Mondo-Mlx-dependent processes, including de novo lipogenesis and fatty acid desaturation. In sum, Mondo-Mlx is a master regulator of other sugar-responsive pathways essential for adaptation to a high-sugar diet.
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Affiliation(s)
- Jaakko Mattila
- Department of Biosciences, University of Helsinki, Helsinki 00790, Finland; Institute of Biotechnology, University of Helsinki, Helsinki 00790, Finland
| | - Essi Havula
- Department of Biosciences, University of Helsinki, Helsinki 00790, Finland; Institute of Biotechnology, University of Helsinki, Helsinki 00790, Finland
| | - Erja Suominen
- Department of Biosciences, University of Helsinki, Helsinki 00790, Finland; Institute of Biotechnology, University of Helsinki, Helsinki 00790, Finland
| | - Mari Teesalu
- Department of Biosciences, University of Helsinki, Helsinki 00790, Finland; Institute of Biotechnology, University of Helsinki, Helsinki 00790, Finland
| | - Ida Surakka
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki 00270, Finland; Department of Health, National Institute for Health and Welfare, Helsinki 00251, Finland
| | - Riikka Hynynen
- Department of Biosciences, University of Helsinki, Helsinki 00790, Finland; Institute of Biotechnology, University of Helsinki, Helsinki 00790, Finland
| | - Helena Kilpinen
- EMBL-EBI, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire CB10 1SD, UK
| | - Juho Väänänen
- Department of Biosciences, University of Helsinki, Helsinki 00790, Finland
| | - Iiris Hovatta
- Department of Biosciences, University of Helsinki, Helsinki 00790, Finland; Department of Health, National Institute for Health and Welfare, Helsinki 00251, Finland
| | - Reijo Käkelä
- Department of Biosciences, University of Helsinki, Helsinki 00790, Finland
| | - Samuli Ripatti
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki 00270, Finland; Health and Substance Abuse Services, National Institute for Health and Welfare, Helsinki 00251, Finland; Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire CB10 1SD, UK
| | - Thomas Sandmann
- Department of Bioinformatics and Computational Biology, Genentech Inc., South San Francisco, CA 94080, USA
| | - Ville Hietakangas
- Department of Biosciences, University of Helsinki, Helsinki 00790, Finland; Institute of Biotechnology, University of Helsinki, Helsinki 00790, Finland.
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Bartok O, Teesalu M, Ashwall-Fluss R, Pandey V, Hanan M, Rovenko BM, Poukkula M, Havula E, Moussaieff A, Vodala S, Nahmias Y, Kadener S, Hietakangas V. The transcription factor Cabut coordinates energy metabolism and the circadian clock in response to sugar sensing. EMBO J 2015; 34:1538-53. [PMID: 25916830 DOI: 10.15252/embj.201591385] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [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: 02/25/2015] [Accepted: 04/01/2015] [Indexed: 12/16/2022] Open
Abstract
Nutrient sensing pathways adjust metabolism and physiological functions in response to food intake. For example, sugar feeding promotes lipogenesis by activating glycolytic and lipogenic genes through the Mondo/ChREBP-Mlx transcription factor complex. Concomitantly, other metabolic routes are inhibited, but the mechanisms of transcriptional repression upon sugar sensing have remained elusive. Here, we characterize cabut (cbt), a transcription factor responsible for the repressive branch of the sugar sensing transcriptional network in Drosophila. We demonstrate that cbt is rapidly induced upon sugar feeding through direct regulation by Mondo-Mlx. We found that CBT represses several metabolic targets in response to sugar feeding, including both isoforms of phosphoenolpyruvate carboxykinase (pepck). Deregulation of pepck1 (CG17725) in mlx mutants underlies imbalance of glycerol and glucose metabolism as well as developmental lethality. Furthermore, we demonstrate that cbt provides a regulatory link between nutrient sensing and the circadian clock. Specifically, we show that a subset of genes regulated by the circadian clock are also targets of CBT. Moreover, perturbation of CBT levels leads to deregulation of the circadian transcriptome and circadian behavioral patterns.
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Affiliation(s)
- Osnat Bartok
- Biological Chemistry Department, Silberman Institute of Life Sciences The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Mari Teesalu
- Department of Biosciences, University of Helsinki, Helsinki, Finland Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Reut Ashwall-Fluss
- Biological Chemistry Department, Silberman Institute of Life Sciences The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Varun Pandey
- Biological Chemistry Department, Silberman Institute of Life Sciences The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Mor Hanan
- Biological Chemistry Department, Silberman Institute of Life Sciences The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Bohdana M Rovenko
- Department of Biosciences, University of Helsinki, Helsinki, Finland Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Minna Poukkula
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Essi Havula
- Department of Biosciences, University of Helsinki, Helsinki, Finland Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Arieh Moussaieff
- Department of Cell Biology, Silberman Institute of Life Sciences The Hebrew University of Jerusalem, Jerusalem, Israel Center for Bioengineering, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Sadanand Vodala
- Howard Hughes Medical Institute, Brandeis University, Waltham, MA, USA
| | - Yaakov Nahmias
- Department of Cell Biology, Silberman Institute of Life Sciences The Hebrew University of Jerusalem, Jerusalem, Israel Center for Bioengineering, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Sebastian Kadener
- Biological Chemistry Department, Silberman Institute of Life Sciences The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Ville Hietakangas
- Department of Biosciences, University of Helsinki, Helsinki, Finland Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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Poukkula M, Hakala M, Pentinmikko N, Sweeney MO, Jansen S, Mattila J, Hietakangas V, Goode BL, Lappalainen P. GMF promotes leading-edge dynamics and collective cell migration in vivo. Curr Biol 2014; 24:2533-40. [PMID: 25308079 DOI: 10.1016/j.cub.2014.08.066] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 08/01/2014] [Accepted: 08/29/2014] [Indexed: 01/22/2023]
Abstract
Lamellipodia are dynamic actin-rich cellular extensions that drive advancement of the leading edge during cell migration. Lamellipodia undergo periodic extension and retraction cycles, but the molecular mechanisms underlying these dynamics and their role in cell migration have remained obscure. We show that glia-maturation factor (GMF), which is an Arp2/3 complex inhibitor and actin filament debranching factor, regulates lamellipodial protrusion dynamics in living cells. In cultured S2R(+) cells, GMF silencing resulted in an increase in the width of lamellipodial actin filament arrays. Importantly, live-cell imaging of mutant Drosophila egg chambers revealed that the dynamics of actin-rich protrusions in migrating border cells is diminished in the absence of GMF. Consequently, velocity of border cell clusters undergoing guided migration was reduced in GMF mutant flies. Furthermore, genetic studies demonstrated that GMF cooperates with the Drosophila homolog of Aip1 (flare) in promoting disassembly of Arp2/3-nucleated actin filament networks and driving border cell migration. These data suggest that GMF functions in vivo to promote the disassembly of Arp2/3-nucleated actin filament arrays, making an important contribution to cell migration within a 3D tissue environment.
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Affiliation(s)
- Minna Poukkula
- Institute of Biotechnology, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Markku Hakala
- Institute of Biotechnology, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Nalle Pentinmikko
- Institute of Biotechnology, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Meredith O Sweeney
- Rosenstiel Center for Basic Biomedical Research, Brandeis University, Waltham, MA 02453, USA
| | - Silvia Jansen
- Rosenstiel Center for Basic Biomedical Research, Brandeis University, Waltham, MA 02453, USA
| | - Jaakko Mattila
- Institute of Biotechnology, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland; Department of Biosciences, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Ville Hietakangas
- Institute of Biotechnology, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland; Department of Biosciences, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Bruce L Goode
- Rosenstiel Center for Basic Biomedical Research, Brandeis University, Waltham, MA 02453, USA
| | - Pekka Lappalainen
- Institute of Biotechnology, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland.
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28
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Kuuluvainen E, Hakala H, Havula E, Sahal Estimé M, Rämet M, Hietakangas V, Mäkelä TP. Cyclin-dependent kinase 8 module expression profiling reveals requirement of mediator subunits 12 and 13 for transcription of Serpent-dependent innate immunity genes in Drosophila. J Biol Chem 2014; 289:16252-61. [PMID: 24778181 DOI: 10.1074/jbc.m113.541904] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The Cdk8 (cyclin-dependent kinase 8) module of Mediator integrates regulatory cues from transcription factors to RNA polymerase II. It consists of four subunits where Med12 and Med13 link Cdk8 and cyclin C (CycC) to core Mediator. Here we have investigated the contributions of the Cdk8 module subunits to transcriptional regulation using RNA interference in Drosophila cells. Genome-wide expression profiling demonstrated separation of Cdk8-CycC and Med12-Med13 profiles. However, transcriptional regulation by Cdk8-CycC was dependent on Med12-Med13. This observation also revealed that Cdk8-CycC and Med12-Med13 often have opposite transcriptional effects. Interestingly, Med12 and Med13 profiles overlapped significantly with that of the GATA factor Serpent. Accordingly, mutational analyses indicated that GATA sites are required for Med12-Med13 regulation of Serpent-dependent genes. Med12 and Med13 were also found to be required for Serpent-activated innate immunity genes in defense to bacterial infection. The results reveal a novel role for the Cdk8 module in Serpent-dependent transcription and innate immunity.
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Affiliation(s)
- Emilia Kuuluvainen
- From the Institute of Biotechnology, University of Helsinki, P. O. Box 56, 00014 Helsinki
| | - Heini Hakala
- From the Institute of Biotechnology, University of Helsinki, P. O. Box 56, 00014 Helsinki
| | - Essi Havula
- From the Institute of Biotechnology, University of Helsinki, P. O. Box 56, 00014 Helsinki, the Department of Biosciences, University of Helsinki, P. O. Box 65, 00014 Helsinki
| | - Michelle Sahal Estimé
- From the Institute of Biotechnology, University of Helsinki, P. O. Box 56, 00014 Helsinki
| | - Mika Rämet
- the Institute of Biomedical Technology, and BioMediTech, University of Tampere, 33014 Tampere, the Department of Pediatrics, Tampere University Hospital, 22521 Tampere, the Department of Pediatrics, Institute of Clinical Medicine, and Medical Research Center Oulu, University of Oulu, 90014 Oulu, and the Department of Children and Adolescents, Oulu University Hospital, 90029 Oulu, Finland
| | - Ville Hietakangas
- From the Institute of Biotechnology, University of Helsinki, P. O. Box 56, 00014 Helsinki, the Department of Biosciences, University of Helsinki, P. O. Box 65, 00014 Helsinki
| | - Tomi P Mäkelä
- From the Institute of Biotechnology, University of Helsinki, P. O. Box 56, 00014 Helsinki,
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29
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Zhang W, Hietakangas V, Wee S, Lim SC, Gunaratne J, Cohen SM. ER stress potentiates insulin resistance through PERK-mediated FOXO phosphorylation. Genes Dev 2013; 27:441-9. [PMID: 23431056 DOI: 10.1101/gad.201731.112] [Citation(s) in RCA: 104] [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] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Endoplasmic reticulum (ER) stress is emerging as a potential contributor to the onset of type 2 diabetes by making cells insulin-resistant. However, our understanding of the mechanisms by which ER stress affects insulin response remains fragmentary. Here we present evidence that the ER stress pathway acts via a conserved signaling mechanism involving the protein kinase PERK to modulate cellular insulin responsiveness. Insulin signaling via AKT reduces activity of FOXO transcription factors. In some cells, PERK can promote insulin responsiveness. However, we found that PERK also acts oppositely via phosphorylation of FOXO to promote FOXO activity. Inhibition of PERK improves cellular insulin responsiveness at the level of FOXO activity. We suggest that the protein kinase PERK may be a promising pharmacological target for ameliorating insulin resistance.
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Affiliation(s)
- Wei Zhang
- Institute of Molecular and Cell Biology, Singapore 138673
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Havula E, Teesalu M, Hyötyläinen T, Seppälä H, Hasygar K, Auvinen P, Orešič M, Sandmann T, Hietakangas V. Mondo/ChREBP-Mlx-regulated transcriptional network is essential for dietary sugar tolerance in Drosophila. PLoS Genet 2013; 9:e1003438. [PMID: 23593032 PMCID: PMC3616910 DOI: 10.1371/journal.pgen.1003438] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [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: 09/05/2012] [Accepted: 02/25/2013] [Indexed: 11/23/2022] Open
Abstract
Sugars are important nutrients for many animals, but are also proposed to contribute to overnutrition-derived metabolic diseases in humans. Understanding the genetic factors governing dietary sugar tolerance therefore has profound biological and medical significance. Paralogous Mondo transcription factors ChREBP and MondoA, with their common binding partner Mlx, are key sensors of intracellular glucose flux in mammals. Here we report analysis of the in vivo function of Drosophila melanogaster Mlx and its binding partner Mondo (ChREBP) in respect to tolerance to dietary sugars. Larvae lacking mlx or having reduced mondo expression show strikingly reduced survival on a diet with moderate or high levels of sucrose, glucose, and fructose. mlx null mutants display widespread changes in lipid and phospholipid profiles, signs of amino acid catabolism, as well as strongly elevated circulating glucose levels. Systematic loss-of-function analysis of Mlx target genes reveals that circulating glucose levels and dietary sugar tolerance can be genetically uncoupled: Krüppel-like transcription factor Cabut and carbonyl detoxifying enzyme Aldehyde dehydrogenase type III are essential for dietary sugar tolerance, but display no influence on circulating glucose levels. On the other hand, Phosphofructokinase 2, a regulator of the glycolysis pathway, is needed for both dietary sugar tolerance and maintenance of circulating glucose homeostasis. Furthermore, we show evidence that fatty acid synthesis, which is a highly conserved Mondo-Mlx-regulated process, does not promote dietary sugar tolerance. In contrast, survival of larvae with reduced fatty acid synthase expression is sugar-dependent. Our data demonstrate that the transcriptional network regulated by Mondo-Mlx is a critical determinant of the healthful dietary spectrum allowing Drosophila to exploit sugar-rich nutrient sources. Diet displays extreme natural variation between animal species, which range from highly specialized carnivores, herbivores, and nectarivores to flexible dietary generalists. Humans are not identical in this respect either, but the genetic background likely defines the framework for a healthy diet. However, we understand poorly the genetic factors that define the spectrum of healthy diet for a given species or individual. Here we have explored the genetic basis of dietary sugar tolerance of Drosophila melanogaster. D. melanogaster is a generalist fruit breeder that feeds on micro-organisms on decaying fruits and vegetables with varying sugar content. However, mutants lacking the conserved Mondo-Mlx transcription factor complex display striking intolerance towards dietary sucrose, glucose, or fructose. This is manifested in the larvae by the inability to grow and pupate on sugar-rich food, including red grape, which belongs to the normal diet of wild D. melanogaster. Larvae lacking Mondo-Mlx show widespread metabolic imbalance, including highly elevated circulating glucose. Genome-wide gene expression analysis combined with systematic loss-of-function screening of Mlx targets reveal that the genetic network providing sugar tolerance includes a secondary transcriptional effector as well as regulators of glycolysis and detoxification of reactive metabolites.
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Affiliation(s)
- Essi Havula
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
- Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Mari Teesalu
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
- Department of Biosciences, University of Helsinki, Helsinki, Finland
| | | | - Heini Seppälä
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
- Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Kiran Hasygar
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
- Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Petri Auvinen
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Matej Orešič
- VTT Technical Research Centre of Finland, Espoo, Finland
| | | | - Ville Hietakangas
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
- Department of Biosciences, University of Helsinki, Helsinki, Finland
- * E-mail:
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31
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Abstract
The paralogous transcription factors ChREBP and MondoA, together with their common binding partner Mlx, have emerged as key mediators of intracellular glucose sensing. By regulating target genes involved in glycolysis and lipogenesis, they mediate metabolic adaptation to changing glucose levels. As disturbed glucose homeostasis plays a central role in human metabolic diseases and as cancer cells often display altered glucose metabolism, better understanding of cellular glucose sensing will likely uncover new therapeutic opportunities. Here we review the regulation, function and evolutionary conservation of the ChREBP/MondoA-Mlx glucose sensing system and discuss possible directions for future research.
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Affiliation(s)
- Essi Havula
- Institute of Biotechnology, University of Helsinki, Viikinkaari 1, 00014 Helsinki, Finland
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32
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Zhang W, Thompson BJ, Hietakangas V, Cohen SM. MAPK/ERK signaling regulates insulin sensitivity to control glucose metabolism in Drosophila. PLoS Genet 2011; 7:e1002429. [PMID: 22242005 PMCID: PMC3248469 DOI: 10.1371/journal.pgen.1002429] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [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: 04/13/2011] [Accepted: 11/04/2011] [Indexed: 01/12/2023] Open
Abstract
The insulin/IGF-activated AKT signaling pathway plays a crucial role in regulating tissue growth and metabolism in multicellular animals. Although core components of the pathway are well defined, less is known about mechanisms that adjust the sensitivity of the pathway to extracellular stimuli. In humans, disturbance in insulin sensitivity leads to impaired clearance of glucose from the blood stream, which is a hallmark of diabetes. Here we present the results of a genetic screen in Drosophila designed to identify regulators of insulin sensitivity in vivo. Components of the MAPK/ERK pathway were identified as modifiers of cellular insulin responsiveness. Insulin resistance was due to downregulation of insulin-like receptor gene expression following persistent MAPK/ERK inhibition. The MAPK/ERK pathway acts via the ETS-1 transcription factor Pointed. This mechanism permits physiological adjustment of insulin sensitivity and subsequent maintenance of circulating glucose at appropriate levels. Insulin signaling is an important and conserved physiological regulator of growth, metabolism, and longevity in multicellular animals. Disturbance in insulin signaling is common in human metabolic disorders. For example insulin resistance is a hallmark of diabetes and metabolic syndrome. While the core components of the insulin signaling pathway have been well established, the mechanisms that adjust the insulin responsiveness are only known to a limited extent. Here we present results from a genetic screen in Drosophila that was designed to identify regulators of cellular insulin sensitivity in an in vivo context. Surprisingly, we discovered cross-talk between the epidermal growth factor receptor (EGFR)–activated MAPK/ERK and insulin signaling pathways. This regulatory mechanism, which involves transcriptional control of insulin-like receptor gene, is utilized in vivo to maintain circulating glucose at appropriate levels. We provide evidence for a regulatory feed-forward mechanism that allows for dynamic transient responsiveness as well as more stable, long-lasting modulation of insulin responsiveness by growth factor receptor signaling. The combination of these mechanisms may contribute to robustness, allowing metabolism to be appropriately responsive to physiological inputs while mitigating the effects of biological noise.
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Affiliation(s)
- Wei Zhang
- Institute of Molecular and Cell Biology, Singapore, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Barry J. Thompson
- London Research Institute, Cancer Research UK, London, United Kingdom
| | - Ville Hietakangas
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
- * E-mail: (VH); (SMC)
| | - Stephen M. Cohen
- Institute of Molecular and Cell Biology, Singapore, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
- * E-mail: (VH); (SMC)
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Abstract
Nutrition is a key regulator of tissue growth. In animals, nutritional status is monitored and signaled at both the cellular and systemic levels. The main mediator of cellular nutrient sensing is the protein kinase TOR (target of rapamycin). TOR receives information from levels of cellular amino acids and energy, and it regulates the activity of processes involved in cell growth, such as protein synthesis and autophagy. Insulin-like signaling is the main mechanism of systemic nutrient sensing and mediates its growth-regulatory functions largely through the phosphatidylinositol 3-kinase (PI3K)/AKT protein kinase pathway. Other nutrition-regulated hormonal mechanisms contribute to growth control by modulating the activity of insulin-like signaling. The pathways mediating signals from systemic and cellular levels converge, allowing cells to combine information from both sources. Here we give an overview of the mechanisms that adjust animal tissue growth in response to nutrition and highlight some general features of the signaling pathways involved.
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Szuplewski S, Sandmann T, Hietakangas V, Cohen SM. Drosophila Minus is required for cell proliferation and influences Cyclin E turnover. Genes Dev 2009; 23:1998-2003. [PMID: 19723762 DOI: 10.1101/gad.1822409] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Turnover of cyclins plays a major role in oscillatory cyclin-dependent kinase (Cdk) activity and control of cell cycle progression. Here we present a novel cell cycle regulator, called minus, which influences Cyclin E turnover in Drosophila. minus mutants produce defects in cell proliferation, some of which are attributable to persistence of Cyclin E. Minus protein can interact physically with Cyclin E and the SCF Archipelago/Fbw7/Cdc4 ubiquitin-ligase complex. Minus does not affect dMyc, another known SCF(Ago) substrate in Drosophila. We propose that Minus contributes to cell cycle regulation in part by selectively controlling turnover of Cyclin E.
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35
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Blomster HA, Hietakangas V, Wu J, Kouvonen P, Hautaniemi S, Sistonen L. Novel proteomics strategy brings insight into the prevalence of SUMO-2 target sites. Mol Cell Proteomics 2009; 8:1382-90. [PMID: 19240082 DOI: 10.1074/mcp.m800551-mcp200] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Small ubiquitin-like modifier (SUMO) is covalently conjugated to its target proteins thereby altering their activity. The mammalian SUMO protein family includes four members (SUMO-1-4) of which SUMO-2 and SUMO-3 are conjugated in a stress-inducible manner. The vast majority of known SUMO substrates are recognized by the single SUMO E2-conjugating enzyme Ubc9 binding to a consensus tetrapeptide (PsiKXE where Psi stands for a large hydrophobic amino acid) or extended motifs that contain phosphorylated or negatively charged amino acids called PDSM (phosphorylation-dependent sumoylation motif) and NDSM (negatively charged amino acid-dependent sumoylation motif), respectively. We identified 382 SUMO-2 targets using a novel method based on SUMO protease treatment that improves separation of SUMO substrates on SDS-PAGE before LC-ESI-MS/MS. We also implemented a software SUMOFI (SUMO motif finder) to facilitate identification of motifs for SUMO substrates from a user-provided set of proteins and to classify the substrates according to the type of SUMO-targeting consensus site. Surprisingly more than half of the substrates lacked any known consensus site, suggesting that numerous SUMO substrates are recognized by a yet unknown consensus site-independent mechanism. Gene ontology analysis revealed that substrates in distinct functional categories display strikingly different prevalences of NDSM sites. Given that different types of motifs are bound by Ubc9 using alternative mechanisms, our data suggest that the preference of SUMO-2 targeting mechanism depends on the biological function of the substrate.
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Affiliation(s)
- Henri A Blomster
- Department of Biology, Abo Akademi University and University of Turku, FI-20521 Turku, Finland
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36
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Hietakangas V, Cohen SM. TOR complex 2 is needed for cell cycle progression and anchorage-independent growth of MCF7 and PC3 tumor cells. BMC Cancer 2008; 8:282. [PMID: 18831768 PMCID: PMC2566983 DOI: 10.1186/1471-2407-8-282] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2008] [Accepted: 10/03/2008] [Indexed: 01/08/2023] Open
Abstract
Background AKT signaling promotes cell growth, proliferation and survival and is hyperactivated in many cancers. TOR complex 2 (TORC2) activates AKT by phosphorylating it on the 'hydrophobic motif' site. Hydrophobic motif site phosphorylation is needed only for a subset of AKT functions. Whether proliferation of tumor cells depends on TORC2 activity has not been thoroughly explored. Methods We used RNAi-mediated knockdown of rictor to inhibit TORC2 activity in MCF7 and PC3 tumor cells to analyze the importance of TORC2 on proliferation of tumor cells. Results TORC2 inhibition reduced proliferation and anchorage-independent growth of both cell lines. Rictor depleted cells accumulated G1 phase, and showed prominent downregulation of Cyclin D1. Conclusion This study provides further evidence that inhibition of TORC2 activity might be a useful strategy to inhibit proliferation of tumor cells and subsequent tumor growth.
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Affiliation(s)
- Ville Hietakangas
- Temasek Life Sciences Laboratory, 1 Research Link, The National University of Singapore, 117604, Singapore.
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37
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Abstract
Transducer of regulated CREB activity 2 (TORC2) is a coactivator of CREB and an important regulator of energy balance in mammals through control of gluconeogenesis in the liver. In this issue of Cell Metabolism, Wang and coworkers (2008) report an intriguing role for Drosophila TORC in the neuronal regulation of metabolism.
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38
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Teleman AA, Hietakangas V, Sayadian AC, Cohen SM. Nutritional control of protein biosynthetic capacity by insulin via Myc in Drosophila. Cell Metab 2008; 7:21-32. [PMID: 18177722 DOI: 10.1016/j.cmet.2007.11.010] [Citation(s) in RCA: 203] [Impact Index Per Article: 12.7] [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] [Received: 06/01/2007] [Revised: 09/28/2007] [Accepted: 11/20/2007] [Indexed: 12/31/2022]
Abstract
Animals use the insulin/TOR signaling pathway to mediate their response to fluctuations in nutrient availability. Energy and amino acids are monitored at the single-cell level via the TOR branch of the pathway and systemically via insulin signaling to regulate cellular growth and metabolism. Using a combination of genetics, expression profiling, and chromatin immunoprecipitation, we examine nutritional control of gene expression and identify the transcription factor Myc as an important mediator of TOR-dependent regulation of ribosome biogenesis. We also identify myc as a direct target of FOXO and provide genetic evidence that Myc has a key role in mediating the effects of TOR and FOXO on growth and metabolism. FOXO and TOR also converge to regulate protein synthesis, acting via 4E-BP and Lk6, regulators of the translation factor eIF4E. This study uncovers a network of convergent regulation of protein biosynthesis by the FOXO and TOR branches of the nutrient-sensing pathway.
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Abstract
Phosphatidylinositol-3-kinase (PI3K)/AKT signaling is essential for growth and metabolism and is elevated in many cancers. Enzymatic activity of AKT has been shown to depend on phosphorylation of two conserved sites by PDK1 and TOR (target of rapamycin) complex 2 (TORC2) in a PI3K-dependent manner. Here we analyze the role of TORC2-mediated AKT phosphorylation in Drosophila. Mutants removing critical TORC2 components, rictor and sin1, strongly reduced AKT hydrophobic motif (HM) phosphorylation and AKT activity, but showed only minor growth impairment. A mutant form of AKT lacking the HM phosphorylation site displayed comparable activity. In contrast to the mild effects of removing HM site phosphorylation at normal levels of PI3K activity, loss of TORC2 activity strongly inhibited hyperplasia caused by elevated pathway activity, as in mutants of the tumor suppressor PTEN. Thus, TORC2 acts as a rheostat to broaden the range of AKT signaling at the high end of its range.
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Affiliation(s)
- Ville Hietakangas
- European Molecular Biology Laboratory Meyerhofstrasse 1, D-69117 Heidelberg, Germany
| | - Stephen M. Cohen
- European Molecular Biology Laboratory Meyerhofstrasse 1, D-69117 Heidelberg, Germany
- Corresponding author.E-MAIL ; FAX 49-6221-387-166
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40
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Abstract
Covalent modification of proteins by the small ubiquitin-related modifier SUMO regulates diverse biological functions. Sumoylation usually requires a consensus tetrapeptide, through which the binding of the SUMO-conjugating enzyme Ubc9 to the target protein is directed. However, additional specificity determinants are in many cases required. To gain insights into SUMO substrate selection, we have utilized the differential sumoylation of highly similar loop structures within the DNA-binding domains of heat shock transcription factor 1 (HSF1) and HSF2. Site-specific mutagenesis in combination with molecular modeling revealed that the sumoylation specificity is determined by several amino acids near the consensus site, which are likely to present the SUMO consensus motif to Ubc9. Importantly, we also demonstrate that sumoylation of the HSF2 loop impedes HSF2 DNA-binding activity, without affecting its oligomerization. Hence, SUMO modification of the HSF2 loop contributes to HSF-specific regulation of DNA binding and broadens the concept of sumoylation in the negative regulation of gene expression.
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Affiliation(s)
- Julius Anckar
- Turku Centre for Biotechnology, P.O. Box 123, FI-20521 Turku, Finland
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41
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Hietakangas V, Anckar J, Blomster HA, Fujimoto M, Palvimo JJ, Nakai A, Sistonen L. PDSM, a motif for phosphorylation-dependent SUMO modification. Proc Natl Acad Sci U S A 2005; 103:45-50. [PMID: 16371476 PMCID: PMC1324973 DOI: 10.1073/pnas.0503698102] [Citation(s) in RCA: 381] [Impact Index Per Article: 20.1] [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: 11/18/2022] Open
Abstract
SUMO (small ubiquitin-like modifier) modification regulates many cellular processes, including transcription. Although sumoylation often occurs on specific lysines within the consensus tetrapeptide PsiKxE, other modifications, such as phosphorylation, may regulate the sumoylation of a substrate. We have discovered PDSM (phosphorylation-dependent sumoylation motif), composed of a SUMO consensus site and an adjacent proline-directed phosphorylation site (PsiKxExxSP). The highly conserved motif regulates phosphorylation-dependent sumoylation of multiple substrates, such as heat-shock factors (HSFs), GATA-1, and myocyte enhancer factor 2. In fact, the majority of the PDSM-containing proteins are transcriptional regulators. Within the HSF family, PDSM is conserved between two functionally distinct members, HSF1 and HSF4b, whose transactivation capacities are repressed through the phosphorylation-dependent sumoylation. As the first recurrent sumoylation determinant beyond the consensus tetrapeptide, the PDSM provides a valuable tool in predicting new SUMO substrates.
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Affiliation(s)
- Ville Hietakangas
- Turku Centre for Biotechnology, University of Turku and Abo Akademi University, FI-20521, Turku, Finland
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Poukkula M, Kaunisto A, Hietakangas V, Denessiouk K, Katajamäki T, Johnson MS, Sistonen L, Eriksson JE. Rapid turnover of c-FLIPshort is determined by its unique C-terminal tail. J Biol Chem 2005; 280:27345-55. [PMID: 15886205 DOI: 10.1074/jbc.m504019200] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.5] [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: 11/06/2022] Open
Abstract
The caspase-8 inhibitor c-FLIP exists as two splice variants, c-FLIP(L) and c-FLIP(S), with distinct roles in death receptor signaling. The mechanisms determining their turnover have not been established. We found that in differentiating K562 erythroleukemia cells both c-FLIP isoforms were inducibly degraded by the proteasome, but c-FLIP(S) was more prone to ubiquitylation and had a considerably shorter half-life. Analysis of the c-FLIP(S)-specific ubiquitylation revealed two lysines, 192 and 195, C-terminal to the death effector domains, as principal ubiquitin acceptors in c-FLIP(S) but not in c-FLIP(L). Furthermore the c-FLIP(S)-specific tail of 19 amino acids, adjacent to the two target lysines, was demonstrated to be the key element determining the isoform-specific instability of c-FLIP(S). Molecular modeling in combination with site-directed mutagenesis demonstrated that the C-terminal tail is required for correct positioning and subsequent ubiquitylation of the target lysines. Because the antiapoptotic operation of c-FLIP(S) was not affected by the tail deletion, the antiapoptotic activity and ubiquitin-mediated degradation of c-FLIP(S) are functionally and structurally independent processes. The presence of a small destabilizing sequence in c-FLIP(S) constitutes an important determinant of c-FLIP(S)/c-FLIP(L) ratios by allowing differential degradation of c-FLIP isoforms. The conformation-based predisposition of c-FLIP(S) to ubiquitin-mediated degradation introduces a novel concept to the regulation of the death-inducing signaling complex.
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Affiliation(s)
- Minna Poukkula
- Turku Centre for Biotechnology, University of Turku and Abo Akademi University, FIN-20521 Turku
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Alastalo TP, Hellesuo M, Sandqvist A, Hietakangas V, Kallio M, Sistonen L. Formation of nuclear stress granules involves HSF2 and coincides with the nucleolar localization of Hsp70. J Cell Sci 2003; 116:3557-70. [PMID: 12865437 DOI: 10.1242/jcs.00671] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.2] [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: 11/20/2022] Open
Abstract
The heat-shock response is characterized by the activation of heat-shock transcription factor 1 (HSF1), followed by increased expression of heat-shock proteins (Hsps). The stress-induced subnuclear compartmentalization of HSF1 into nuclear stress granules has been suggested to be an important control step in the regulation of stress response and cellular homeostasis in human cells. In this study, we demonstrate that the less-well characterized HSF2 interacts physically with HSF1 and is a novel stress-responsive component of the stress granules. Based on analysis of our deletion mutants, HSF2 influences to the localization of HSF1 in stress granules. Moreover, our results indicate that the stress granules are dynamic structures and suggest that they might be regulated in an Hsp70-dependent manner. The reversible localization of Hsp70 in the nucleoli strictly coincides with the presence of HSF1 in stress granules and is dramatically suppressed in thermotolerant cells. We propose that the regulated subcellular distribution of Hsp70 is an important regulatory mechanism of HSF1-mediated heat shock response.
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Affiliation(s)
- Tero-Pekka Alastalo
- Turku Centre for Biotechnology, University of Turku, Abo Akademi University, BioCity, PO Box 123, FIN-20521 Turku, Finland
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Hietakangas V, Ahlskog JK, Jakobsson AM, Hellesuo M, Sahlberg NM, Holmberg CI, Mikhailov A, Palvimo JJ, Pirkkala L, Sistonen L. Phosphorylation of serine 303 is a prerequisite for the stress-inducible SUMO modification of heat shock factor 1. Mol Cell Biol 2003; 23:2953-68. [PMID: 12665592 PMCID: PMC152542 DOI: 10.1128/mcb.23.8.2953-2968.2003] [Citation(s) in RCA: 225] [Impact Index Per Article: 10.7] [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: 07/15/2002] [Revised: 08/29/2002] [Accepted: 01/27/2003] [Indexed: 01/04/2023] Open
Abstract
The heat shock response, which is accompanied by a rapid and robust upregulation of heat shock proteins (Hsps), is a highly conserved protection mechanism against protein-damaging stress. Hsp induction is mainly regulated at transcriptional level by stress-inducible heat shock factor 1 (HSF1). Upon activation, HSF1 trimerizes, binds to DNA, concentrates in the nuclear stress granules, and undergoes a marked multisite phosphorylation, which correlates with its transcriptional activity. In this study, we show that HSF1 is modified by SUMO-1 and SUMO-2 in a stress-inducible manner. Sumoylation is rapidly and transiently enhanced on lysine 298, located in the regulatory domain of HSF1, adjacent to several critical phosphorylation sites. Sumoylation analyses of HSF1 phosphorylation site mutants reveal that specifically the phosphorylation-deficient S303 mutant remains devoid of SUMO modification in vivo and the mutant mimicking phosphorylation of S303 promotes HSF1 sumoylation in vitro, indicating that S303 phosphorylation is required for K298 sumoylation. This finding is further supported by phosphopeptide mapping and analysis with S303/7 phosphospecific antibodies, which demonstrate that serine 303 is a target for strong heat-inducible phosphorylation, corresponding to the inducible HSF1 sumoylation. A transient phosphorylation-dependent colocalization of HSF1 and SUMO-1 in nuclear stress granules provides evidence for a strictly regulated subnuclear interplay between HSF1 and SUMO.
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Affiliation(s)
- Ville Hietakangas
- Turku Centre for Biotechnology, University of Turku and Abo Akademi University and Department of Biochemistry and Food Chemistry, University of Turku, Finland
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Hietakangas V, Poukkula M, Heiskanen KM, Karvinen JT, Sistonen L, Eriksson JE. Erythroid differentiation sensitizes K562 leukemia cells to TRAIL-induced apoptosis by downregulation of c-FLIP. Mol Cell Biol 2003; 23:1278-91. [PMID: 12556488 PMCID: PMC141136 DOI: 10.1128/mcb.23.4.1278-1291.2003] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.0] [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: 01/07/2023] Open
Abstract
Regulation of the apoptotic threshold is of great importance in the homeostasis of both differentiating and fully developed organ systems. Triggering differentiation has been employed as a strategy to inhibit cell proliferation and accelerate apoptosis in malignant cells, in which the apoptotic threshold is often characteristically elevated. To better understand the mechanisms underlying differentiation-mediated regulation of apoptosis, we have studied death receptor responses during erythroid differentiation of K562 erythroleukemia cells, which normally are highly resistant to tumor necrosis factor (TNF) alpha-, FasL-, and TRAIL-induced apoptosis. However, upon hemin-mediated erythroid differentiation, K562 cells specifically lost their resistance to TNF-related apoptosis-inducing ligand (TRAIL), which efficiently killed the differentiating cells independently of mitochondrial apoptotic signaling. Concomitantly with the increased sensitivity, the expression of both c-FLIP splicing variants, c-FLIP(L) and c-FLIP(S), was downregulated, resulting in an altered caspase 8 recruitment and cleavage in the death-inducing signaling complex (DISC). Stable overexpression of both c-FLIP(L) and c-FLIP(S) rescued the cells from TRAIL-mediated apoptosis with isoform-specific effects on DISC-recruited caspase 8. Our results show that c-FLIP(L) and c-FLIP(S) potently control TRAIL responses, both by distinct regulatory features, and further imply that the differentiation state of malignant cells determines their sensitivity to death receptor signals.
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Affiliation(s)
- Ville Hietakangas
- Turku Centre for Biotechnology, University of Turku and Abo Akademi University, FIN-20521 Turku, Finland
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Hietakangas V, Elo I, Rosenström H, Coffey ET, Kyriakis JM, Eriksson JE, Sistonen L. Activation of the MKK4-JNK pathway during erythroid differentiation of K562 cells is inhibited by the heat shock factor 2-beta isoform. FEBS Lett 2001; 505:168-72. [PMID: 11557063 DOI: 10.1016/s0014-5793(01)02810-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [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: 10/27/2022]
Abstract
In this study we report the activation of c-Jun N-terminal kinase (JNK) in human K562 erythroleukemia cells undergoing hemin-mediated erythroid differentiation, which occurs concomitantly with activation of heat shock factor 2 (HSF2) and leads to a simultaneous in vivo phosphorylation of c-Jun. The activation of JNK occurs through activation of mitogen-activated protein kinase kinase (MKK) 4 and not by activation of MKK7 or inhibition of JNK-directed phosphatases. We have previously shown that overexpression of the HSF2-beta isoform inhibits the activation of HSF2 upon hemin-induced erythroid differentiation. Here we demonstrate that HSF2-beta overexpression blocks the hemin-induced activation of the MKK4-JNK pathway, suggesting an erythroid lineage-specific JNK activation likely to be regulated by HSF2.
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Affiliation(s)
- V Hietakangas
- Turku Centre for Biotechnology, University of Turku, Abo Akademi University, Finland
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Holmberg CI, Hietakangas V, Mikhailov A, Rantanen JO, Kallio M, Meinander A, Hellman J, Morrice N, MacKintosh C, Morimoto RI, Eriksson JE, Sistonen L. Phosphorylation of serine 230 promotes inducible transcriptional activity of heat shock factor 1. EMBO J 2001; 20:3800-10. [PMID: 11447121 PMCID: PMC125548 DOI: 10.1093/emboj/20.14.3800] [Citation(s) in RCA: 224] [Impact Index Per Article: 9.7] [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] [Indexed: 11/13/2022] Open
Abstract
Heat shock factor 1 (HSF1) is a serine-rich constitutively phosphorylated mediator of the stress response. Upon stress, HSF1 forms DNA-binding trimers, relocalizes to nuclear granules, undergoes inducible phosphorylation and acquires the properties of a transactivator. HSF1 is phosphorylated on multiple sites, but the sites and their function have remained an enigma. Here, we have analyzed sites of endogenous phosphorylation on human HSF1 and developed a phosphopeptide antibody to identify Ser230 as a novel in vivo phosphorylation site. Ser230 is located in the regulatory domain of HSF1, and promotes the magnitude of the inducible transcriptional activity. Ser230 lies within a consensus site for calcium/calmodulin-dependent protein kinase II (CaMKII), and CaMKII overexpression enhances both the level of in vivo Ser230 phosphorylation and transactivation of HSF1. The importance of Ser230 was further established by the S230A HSF1 mutant showing markedly reduced activity relative to wild-type HSF1 when expressed in hsf1(-/-) cells. Our study provides the first evidence that phosphorylation is essential for the transcriptional activity of HSF1, and hence for induction of the heat shock response.
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Affiliation(s)
- Carina I. Holmberg
- Turku Centre for Biotechnology, University of Turku, Åbo Akademi University, Department of Biochemistry and Food Chemistry and Department of Biology, University of Turku, Department of Biology, Åbo Akademi University, Finland, MRC Protein Phosphorylation Unit, Department of Biochemistry, University of Dundee, UK and Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, IL, USA Corresponding author at Turku Centre for Biotechnology, PO Box 123, FIN-20521 Turku, Finland e-mail:
| | - Ville Hietakangas
- Turku Centre for Biotechnology, University of Turku, Åbo Akademi University, Department of Biochemistry and Food Chemistry and Department of Biology, University of Turku, Department of Biology, Åbo Akademi University, Finland, MRC Protein Phosphorylation Unit, Department of Biochemistry, University of Dundee, UK and Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, IL, USA Corresponding author at Turku Centre for Biotechnology, PO Box 123, FIN-20521 Turku, Finland e-mail:
| | - Andrey Mikhailov
- Turku Centre for Biotechnology, University of Turku, Åbo Akademi University, Department of Biochemistry and Food Chemistry and Department of Biology, University of Turku, Department of Biology, Åbo Akademi University, Finland, MRC Protein Phosphorylation Unit, Department of Biochemistry, University of Dundee, UK and Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, IL, USA Corresponding author at Turku Centre for Biotechnology, PO Box 123, FIN-20521 Turku, Finland e-mail:
| | - Jouni O. Rantanen
- Turku Centre for Biotechnology, University of Turku, Åbo Akademi University, Department of Biochemistry and Food Chemistry and Department of Biology, University of Turku, Department of Biology, Åbo Akademi University, Finland, MRC Protein Phosphorylation Unit, Department of Biochemistry, University of Dundee, UK and Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, IL, USA Corresponding author at Turku Centre for Biotechnology, PO Box 123, FIN-20521 Turku, Finland e-mail:
| | - Marko Kallio
- Turku Centre for Biotechnology, University of Turku, Åbo Akademi University, Department of Biochemistry and Food Chemistry and Department of Biology, University of Turku, Department of Biology, Åbo Akademi University, Finland, MRC Protein Phosphorylation Unit, Department of Biochemistry, University of Dundee, UK and Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, IL, USA Corresponding author at Turku Centre for Biotechnology, PO Box 123, FIN-20521 Turku, Finland e-mail:
| | - Annika Meinander
- Turku Centre for Biotechnology, University of Turku, Åbo Akademi University, Department of Biochemistry and Food Chemistry and Department of Biology, University of Turku, Department of Biology, Åbo Akademi University, Finland, MRC Protein Phosphorylation Unit, Department of Biochemistry, University of Dundee, UK and Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, IL, USA Corresponding author at Turku Centre for Biotechnology, PO Box 123, FIN-20521 Turku, Finland e-mail:
| | - Jukka Hellman
- Turku Centre for Biotechnology, University of Turku, Åbo Akademi University, Department of Biochemistry and Food Chemistry and Department of Biology, University of Turku, Department of Biology, Åbo Akademi University, Finland, MRC Protein Phosphorylation Unit, Department of Biochemistry, University of Dundee, UK and Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, IL, USA Corresponding author at Turku Centre for Biotechnology, PO Box 123, FIN-20521 Turku, Finland e-mail:
| | - Nick Morrice
- Turku Centre for Biotechnology, University of Turku, Åbo Akademi University, Department of Biochemistry and Food Chemistry and Department of Biology, University of Turku, Department of Biology, Åbo Akademi University, Finland, MRC Protein Phosphorylation Unit, Department of Biochemistry, University of Dundee, UK and Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, IL, USA Corresponding author at Turku Centre for Biotechnology, PO Box 123, FIN-20521 Turku, Finland e-mail:
| | - Carol MacKintosh
- Turku Centre for Biotechnology, University of Turku, Åbo Akademi University, Department of Biochemistry and Food Chemistry and Department of Biology, University of Turku, Department of Biology, Åbo Akademi University, Finland, MRC Protein Phosphorylation Unit, Department of Biochemistry, University of Dundee, UK and Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, IL, USA Corresponding author at Turku Centre for Biotechnology, PO Box 123, FIN-20521 Turku, Finland e-mail:
| | - Richard I. Morimoto
- Turku Centre for Biotechnology, University of Turku, Åbo Akademi University, Department of Biochemistry and Food Chemistry and Department of Biology, University of Turku, Department of Biology, Åbo Akademi University, Finland, MRC Protein Phosphorylation Unit, Department of Biochemistry, University of Dundee, UK and Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, IL, USA Corresponding author at Turku Centre for Biotechnology, PO Box 123, FIN-20521 Turku, Finland e-mail:
| | - John E. Eriksson
- Turku Centre for Biotechnology, University of Turku, Åbo Akademi University, Department of Biochemistry and Food Chemistry and Department of Biology, University of Turku, Department of Biology, Åbo Akademi University, Finland, MRC Protein Phosphorylation Unit, Department of Biochemistry, University of Dundee, UK and Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, IL, USA Corresponding author at Turku Centre for Biotechnology, PO Box 123, FIN-20521 Turku, Finland e-mail:
| | - Lea Sistonen
- Turku Centre for Biotechnology, University of Turku, Åbo Akademi University, Department of Biochemistry and Food Chemistry and Department of Biology, University of Turku, Department of Biology, Åbo Akademi University, Finland, MRC Protein Phosphorylation Unit, Department of Biochemistry, University of Dundee, UK and Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, IL, USA Corresponding author at Turku Centre for Biotechnology, PO Box 123, FIN-20521 Turku, Finland e-mail:
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