1
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Grimm PR, Tatomir A, Rosenbaek LL, Kim BY, Li D, Delpire EJ, Fenton RA, Welling PA. Dietary potassium stimulates Ppp1Ca-Ppp1r1a dephosphorylation of kidney NaCl cotransporter and reduces blood pressure. J Clin Invest 2023; 133:e158498. [PMID: 37676724 PMCID: PMC10617769 DOI: 10.1172/jci158498] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 09/06/2023] [Indexed: 09/09/2023] Open
Abstract
Consumption of low dietary potassium, common with ultraprocessed foods, activates the thiazide-sensitive sodium chloride cotransporter (NCC) via the with no (K) lysine kinase/STE20/SPS1-related proline-alanine-rich protein kinase (WNK/SPAK) pathway to induce salt retention and elevate blood pressure (BP). However, it remains unclear how high-potassium "DASH-like" diets (dietary approaches to stop hypertension) inactivate the cotransporter and whether this decreases BP. A transcriptomics screen identified Ppp1Ca, encoding PP1A, as a potassium-upregulated gene, and its negative regulator Ppp1r1a, as a potassium-suppressed gene in the kidney. PP1A directly binds to and dephosphorylates NCC when extracellular potassium is elevated. Using mice genetically engineered to constitutively activate the NCC-regulatory kinase SPAK and thereby eliminate the effects of the WNK/SPAK kinase cascade, we confirmed that PP1A dephosphorylated NCC directly in a potassium-regulated manner. Prior adaptation to a high-potassium diet was required to maximally dephosphorylate NCC and lower BP in constitutively active SPAK mice, and this was associated with potassium-dependent suppression of Ppp1r1a and dephosphorylation of its cognate protein, inhibitory subunit 1 (I1). In conclusion, potassium-dependent activation of PP1A and inhibition of I1 drove NCC dephosphorylation, providing a mechanism to explain how high dietary K+ lowers BP. Shifting signaling of PP1A in favor of activation of WNK/SPAK may provide an improved therapeutic approach for treating salt-sensitive hypertension.
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Affiliation(s)
- P. Richard Grimm
- Department of Medicine (Nephrology), Johns Hopkins University School of Medicine Baltimore, Maryland, USA
- The LeDucq Potassium in Hypertension Research Network of Excellence is detailed in Supplemental Acknowledgments
| | - Anamaria Tatomir
- Department of Medicine (Nephrology), Johns Hopkins University School of Medicine Baltimore, Maryland, USA
| | - Lena L. Rosenbaek
- The LeDucq Potassium in Hypertension Research Network of Excellence is detailed in Supplemental Acknowledgments
- Department of Biomedicine, University of Aarhus, Aarhus, Denmark
| | - Bo Young Kim
- Department of Medicine (Nephrology), Johns Hopkins University School of Medicine Baltimore, Maryland, USA
- The LeDucq Potassium in Hypertension Research Network of Excellence is detailed in Supplemental Acknowledgments
| | - Dimin Li
- Department of Medicine (Nephrology), Johns Hopkins University School of Medicine Baltimore, Maryland, USA
| | - Eric J. Delpire
- The LeDucq Potassium in Hypertension Research Network of Excellence is detailed in Supplemental Acknowledgments
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennssee, USA
| | - Robert A. Fenton
- The LeDucq Potassium in Hypertension Research Network of Excellence is detailed in Supplemental Acknowledgments
- Department of Biomedicine, University of Aarhus, Aarhus, Denmark
| | - Paul A. Welling
- Department of Medicine (Nephrology), Johns Hopkins University School of Medicine Baltimore, Maryland, USA
- The LeDucq Potassium in Hypertension Research Network of Excellence is detailed in Supplemental Acknowledgments
- Department of Physiology, Johns Hopkins University School of Medicine Baltimore, Maryland, USA
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2
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Azizi SA, Qiu T, Brookes NE, Dickinson BC. Regulation of ERK2 activity by dynamic S-acylation. Cell Rep 2023; 42:113135. [PMID: 37715953 PMCID: PMC10591828 DOI: 10.1016/j.celrep.2023.113135] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 07/28/2023] [Accepted: 08/30/2023] [Indexed: 09/18/2023] Open
Abstract
Extracellular signal-regulated kinases (ERK1/2) are key effector proteins of the mitogen-activated protein kinase pathway, choreographing essential processes of cellular physiology. Here, we discover that ERK1/2 are subject to S-acylation, a reversible lipid modification of cysteine residues, at C271/C254. The levels of ERK1/2 S-acylation are modulated by epidermal growth factor (EGF) signaling, mirroring its phosphorylation dynamics, and acylation-deficient ERK2 displays altered phosphorylation patterns. We show that ERK1/2 S-acylation is mediated by "writer" protein acyl transferases (PATs) and "eraser" acyl protein thioesterases (APTs) and that chemical inhibition of either lipid addition or removal alters ERK1/2's EGF-triggered transcriptional program. Finally, in a mouse model of metabolic syndrome, we find that ERK1/2 lipidation levels correlate with alterations in ERK1/2 lipidation writer/eraser expression, solidifying a link between ERK1/2 activity, ERK1/2 lipidation, and organismal health. This study describes how lipidation regulates ERK1/2 and offers insight into the role of dynamic S-acylation in cell signaling more broadly.
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Affiliation(s)
- Saara-Anne Azizi
- Department of Chemistry, The University of Chicago, Chicago, IL 60637, USA; Medical Scientist Training Program, Pritzker School of Medicine, The University of Chicago, Chicago, IL 60637, USA
| | - Tian Qiu
- Department of Chemistry, The University of Chicago, Chicago, IL 60637, USA
| | - Noah E Brookes
- Department of Chemistry, The University of Chicago, Chicago, IL 60637, USA
| | - Bryan C Dickinson
- Department of Chemistry, The University of Chicago, Chicago, IL 60637, USA.
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3
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Simpson LM, Fulcher LJ, Sathe G, Brewer A, Zhao JF, Squair DR, Crooks J, Wightman M, Wood NT, Gourlay R, Varghese J, Soares RF, Sapkota GP. An affinity-directed phosphatase, AdPhosphatase, system for targeted protein dephosphorylation. Cell Chem Biol 2023; 30:188-202.e6. [PMID: 36720221 DOI: 10.1016/j.chembiol.2023.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 11/07/2022] [Accepted: 01/10/2023] [Indexed: 02/02/2023]
Abstract
Reversible protein phosphorylation, catalyzed by protein kinases and phosphatases, is a fundamental process that controls protein function and intracellular signaling. Failure of phospho-control accounts for many human diseases. While a kinase phosphorylates multiple substrates, a substrate is often phosphorylated by multiple kinases. This renders phospho-control at the substrate level challenging, as it requires inhibition of multiple kinases, which would thus affect other kinase substrates. Here, we describe the development and application of the affinity-directed phosphatase (AdPhosphatase) system for targeted dephosphorylation of specific phospho-substrates. By deploying the Protein Phosphatase 1 or 2A catalytic subunits conjugated to an antigen-stabilized anti-GFP nanobody, we can promote the dephosphorylation of two independent phospho-proteins, FAM83D or ULK1, knocked in with GFP-tags using CRISPR-Cas9, with exquisite specificity. By redirecting protein phosphatases to neo-substrates through nanobody-mediated proximity, AdPhosphatase can alter the phospho-status and function of target proteins and thus, offers a new modality for potential drug discovery approaches.
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Affiliation(s)
- Luke M Simpson
- Medical Research Council (MRC) Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Luke J Fulcher
- Medical Research Council (MRC) Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Gajanan Sathe
- Medical Research Council (MRC) Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Abigail Brewer
- Medical Research Council (MRC) Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Jin-Feng Zhao
- Medical Research Council (MRC) Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Daniel R Squair
- Medical Research Council (MRC) Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Jennifer Crooks
- Medical Research Council (MRC) Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Melanie Wightman
- Medical Research Council (MRC) Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Nicola T Wood
- Medical Research Council (MRC) Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Robert Gourlay
- Medical Research Council (MRC) Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Joby Varghese
- Medical Research Council (MRC) Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Renata F Soares
- Medical Research Council (MRC) Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Gopal P Sapkota
- Medical Research Council (MRC) Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.
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4
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Tingting Gan, Liu X, Chen X, Shi Y, Wang W. Okadaic Acid Inhibits Protein Phosphatases to Suppress Spermatogonial Cell Proliferation. BIOL BULL+ 2022. [DOI: 10.1134/s1062359022140060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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5
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Lee E, Liu Z, Nguyen N, Nairn A, Chang AN. Myosin light chain phosphatase catalytic subunit dephosphorylates cardiac myosin via mechanisms dependent and independent of the MYPT regulatory subunits. J Biol Chem 2022; 298:102296. [PMID: 35872014 PMCID: PMC9418503 DOI: 10.1016/j.jbc.2022.102296] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 07/11/2022] [Accepted: 07/12/2022] [Indexed: 11/27/2022] Open
Abstract
Cardiac muscle myosin regulatory light chain (RLC) is constitutively phosphorylated at ∼0.4 mol phosphate/mol RLC in normal hearts, and phosphorylation is maintained by balanced activities of dedicated cardiac muscle–specific myosin light chain kinase and myosin light chain phosphatase (MLCP). Previously, the identity of the cardiac-MLCP was biochemically shown to be similar to the smooth muscle MLCP, which is a well-characterized trimeric protein comprising the regulatory subunit (MYPT1), catalytic subunit PP1cβ, and accessory subunit M20. In smooth muscles in vivo, MYPT1 and PP1cβ co-stabilize each other and are both necessary for normal smooth muscle contractions. In the cardiac muscle, MYPT1 and MYPT2 are both expressed, but contributions to physiological regulation of cardiac myosin dephosphorylation are unclear. We hypothesized that the main catalytic subunit for cardiac-MLCP is PP1cβ, and maintenance of RLC phosphorylation in vivo is dependent on regulation by striated muscle–specific MYPT2. Here, we used PP1cβ conditional knockout mice to biochemically define cardiac-MLCP proteins and developed a cardiac myofibrillar phosphatase assay to measure the direct contribution of MYPT-regulated and MYPT-independent phosphatase activities toward phosphorylated cardiac myosin. We report that (1) PP1cβ is the main isoform expressed in the cardiac myocyte, (2) cardiac muscle pathogenesis in PP1cβ knockout animals involve upregulation of total PP1cα in myocytes and non-muscle cells, (3) the stability of cardiac MYPT1 and MYPT2 proteins in vivo is not dependent on the PP1cβ expression, and (4) phosphorylated myofibrillar cardiac myosin is dephosphorylated by both myosin-targeted and soluble MYPT-independent PP1cβ activities. These results contribute to our understanding of the cardiac-MLCP in vivo.
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Affiliation(s)
- Eunyoung Lee
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas Texas 75390 USA
| | - Zhenan Liu
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas Texas 75390 USA
| | - Nhu Nguyen
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas Texas 75390 USA
| | - Angus Nairn
- Department of Psychiatry, Yale University School of Medicine, New Haven CT 06508 USA
| | - Audrey N Chang
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas Texas 75390 USA; Pak Center for Mineral Metabolism and Clinical Research, UTSW Medical Center, Dallas Texas 75390 USA.
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6
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Sule A, Golding SE, Ahmad SF, Watson J, Ahmed MH, Kellogg GE, Bernas T, Koebley S, Reed JC, Povirk LF, Valerie K. ATM phosphorylates PP2A subunit A resulting in nuclear export and spatiotemporal regulation of the DNA damage response. Cell Mol Life Sci 2022; 79:603. [PMID: 36434396 PMCID: PMC9700600 DOI: 10.1007/s00018-022-04550-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 08/30/2022] [Accepted: 09/07/2022] [Indexed: 11/26/2022]
Abstract
Ataxia telangiectasia mutated (ATM) is a serine-threonine protein kinase and important regulator of the DNA damage response (DDR). One critical ATM target is the structural subunit A (PR65-S401) of protein phosphatase 2A (PP2A), known to regulate diverse cellular processes such as mitosis and cell growth as well as dephosphorylating many proteins during the recovery from the DDR. We generated mouse embryonic fibroblasts expressing PR65-WT, -S401A (cannot be phosphorylated), and -S401D (phospho-mimetic) transgenes. Significantly, S401 mutants exhibited extensive chromosomal aberrations, impaired DNA double-strand break (DSB) repair and underwent increased mitotic catastrophe after radiation. Both S401A and the S401D cells showed impaired DSB repair (nonhomologous end joining and homologous recombination repair) and exhibited delayed DNA damage recovery, which was reflected in reduced radiation survival. Furthermore, S401D cells displayed increased ERK and AKT signaling resulting in enhanced growth rate further underscoring the multiple roles ATM-PP2A signaling plays in regulating prosurvival responses. Time-lapse video and cellular localization experiments showed that PR65 was exported to the cytoplasm after radiation by CRM1, a nuclear export protein, in line with the very rapid pleiotropic effects observed. A putative nuclear export sequence (NES) close to S401 was identified and when mutated resulted in aberrant PR65 shuttling. Our study demonstrates that the phosphorylation of a single, critical PR65 amino acid (S401) by ATM fundamentally controls the DDR, and balances DSB repair quality, cell survival and growth by spatiotemporal PR65 nuclear-cytoplasmic shuttling mediated by the nuclear export receptor CRM1.
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Affiliation(s)
- Amrita Sule
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA, 23298-0058, USA
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Sarah E Golding
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA, 23298-0058, USA
| | - Syed F Ahmad
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA, 23298-0058, USA
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - James Watson
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA, 23298-0058, USA
| | - Mostafa H Ahmed
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Glen E Kellogg
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA, 23298, USA
- Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Tytus Bernas
- Department of Anatomy, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Sean Koebley
- Department of Physics, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Jason C Reed
- Department of Physics, Virginia Commonwealth University, Richmond, VA, 23298, USA
- Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Lawrence F Povirk
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, 23298, USA
- Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Kristoffer Valerie
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA, 23298-0058, USA.
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA, 23298, USA.
- Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, 23298, USA.
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7
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Wu CH, Tatavarty V, Jean Beltran PM, Guerrero AA, Keshishian H, Krug K, MacMullan MA, Li L, Carr SA, Cottrell JR, Turrigiano GG. A bidirectional switch in the Shank3 phosphorylation state biases synapses toward up- or downscaling. eLife 2022; 11:74277. [PMID: 35471151 PMCID: PMC9084893 DOI: 10.7554/elife.74277] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 04/25/2022] [Indexed: 11/13/2022] Open
Abstract
Homeostatic synaptic plasticity requires widespread remodeling of synaptic signaling and scaffolding networks, but the role of post-translational modifications in this process has not been systematically studied. Using deep-scale quantitative analysis of the phosphoproteome in mouse neocortical neurons, we found widespread and temporally complex changes during synaptic scaling up and down. We observed 424 bidirectionally modulated phosphosites that were strongly enriched for synapse-associated proteins, including S1539 in the autism spectrum disorder-associated synaptic scaffold protein Shank3. Using a parallel proteomic analysis performed on Shank3 isolated from rat neocortical neurons by immunoaffinity, we identified two sites that were persistently hypophosphorylated during scaling up and transiently hyperphosphorylated during scaling down: one (rat S1615) that corresponded to S1539 in mouse, and a second highly conserved site, rat S1586. The phosphorylation status of these sites modified the synaptic localization of Shank3 during scaling protocols, and dephosphorylation of these sites via PP2A activity was essential for the maintenance of synaptic scaling up. Finally, phosphomimetic mutations at these sites prevented scaling up but not down, while phosphodeficient mutations prevented scaling down but not up. These mutations did not impact baseline synaptic strength, indicating that they gate, rather than drive, the induction of synaptic scaling. Thus, an activity-dependent switch between hypo- and hyperphosphorylation at S1586 and S1615 of Shank3 enables scaling up or down, respectively. Collectively, our data show that activity-dependent phosphoproteome dynamics are important for the functional reconfiguration of synaptic scaffolds and can bias synapses toward upward or downward homeostatic plasticity.
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Affiliation(s)
- Chi-Hong Wu
- Department of Biology, Brandeis UniversityWalthamUnited States
| | | | | | | | - Hasmik Keshishian
- Proteomics Platform, Broad Institute of MIT and HarvardCambridgeUnited States
| | - Karsten Krug
- Proteomics Platform, Broad Institute of MIT and HarvardCambridgeUnited States
| | - Melanie A MacMullan
- Proteomics Platform, Broad Institute of MIT and HarvardCambridgeUnited States
| | - Li Li
- Stanley Center for Psychiatric Research, Broad Institute of MIT and HarvardCambridgeUnited States
| | - Steven A Carr
- Proteomics Platform, Broad Institute of MIT and HarvardCambridgeUnited States
| | - Jeffrey R Cottrell
- Stanley Center for Psychiatric Research, Broad Institute of MIT and HarvardCambridgeUnited States
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8
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Kocakaplan D, Karabürk H, Dilege C, Kirdök I, Bektas SN, Caydasi AK. Protein phosphatase 1 in association with Bud14 inhibits mitotic exit in Saccharomyces cerevisiae. eLife 2021; 10:72833. [PMID: 34633288 PMCID: PMC8577847 DOI: 10.7554/elife.72833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 10/08/2021] [Indexed: 11/18/2022] Open
Abstract
Mitotic exit in budding yeast is dependent on correct orientation of the mitotic spindle along the cell polarity axis. When accurate positioning of the spindle fails, a surveillance mechanism named the spindle position checkpoint (SPOC) prevents cells from exiting mitosis. Mutants with a defective SPOC become multinucleated and lose their genomic integrity. Yet, a comprehensive understanding of the SPOC mechanism is missing. In this study, we identified the type 1 protein phosphatase, Glc7, in association with its regulatory protein Bud14 as a novel checkpoint component. We further showed that Glc7-Bud14 promotes dephosphorylation of the SPOC effector protein Bfa1. Our results suggest a model in which two mechanisms act in parallel for a robust checkpoint response: first, the SPOC kinase Kin4 isolates Bfa1 away from the inhibitory kinase Cdc5, and second, Glc7-Bud14 dephosphorylates Bfa1 to fully activate the checkpoint effector.
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Affiliation(s)
- Dilara Kocakaplan
- Department of Molecular Biology and Genetics, Koç University, Istanbul, Turkey
| | - Hüseyin Karabürk
- Department of Molecular Biology and Genetics, Koç University, Istanbul, Turkey
| | - Cansu Dilege
- Department of Molecular Biology and Genetics, Koç University, Istanbul, Turkey
| | - Idil Kirdök
- Department of Molecular Biology and Genetics, Koç University, Istanbul, Turkey
| | - Seyma Nur Bektas
- Department of Molecular Biology and Genetics, Koç University, Istanbul, Turkey
| | - Ayse Koca Caydasi
- Department of Molecular Biology and Genetics, Koç University, Istanbul, Turkey
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9
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Chen C, Huang FW, Huang SS, Huang JS. IGFBP-3 and TGF-β inhibit growth in epithelial cells by stimulating type V TGF-β receptor (TβR-V)-mediated tumor suppressor signaling. FASEB Bioadv 2021; 3:709-729. [PMID: 34485840 PMCID: PMC8409558 DOI: 10.1096/fba.2021-00016] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 04/06/2021] [Accepted: 04/23/2021] [Indexed: 12/13/2022] Open
Abstract
The TGF-β type V receptor (TβR-V) mediates growth inhibition by IGFBP-3 and TGF-β in epithelial cells and loss of TβR-V expression in these cells leads to development of carcinoma. The mechanisms by which TβR-V mediates growth inhibition (tumor suppressor) signaling remain elusive. Previous studies revealed that IGFBP-3 and TGF-β inhibit growth in epithelial cells by stimulating TβR-V-mediated IRS-1/2-dependent activation and cytoplasm-to-nucleus translocation of IGFBP-3- or TGF-β-stimulated protein phosphatase (PPase), resulting in dephosphorylation of pRb-related proteins (p107, p130) or pRb, and growth arrest. To define the signaling, we characterized/identified the IGFBP-3- and TGF-β-stimulated PPases in cell lysates and nucleus fractions in Mv1Lu cells treated with IGFBP-3 and TGF-β, using a cell-free assay with 32P-labeled casein as a substrate. Both IGFBP-3- and TGF-β-stimulated PPase activities in cell lysates are abolished when cells are co-treated with TGF-β/IGFBP-3 antagonist or RAP (LRP-1/TβR-V antagonist). However, the IGFBP-3-stimulated PPase activity, but not TGF-β-stimulated PPase activity, is sensitive to inhibition by okadaic acid (OA). In addition, OA or PP2Ac siRNA reverses IGFBP-3 growth inhibition, but not TGF-β growth inhibition, in Mv1Lu and 32D cells. These suggest that IGFBP-3- and TGF-β-stimulated PPases are identical to PP2A and PP1, respectively. By Western blot/phosphorimager/immunofluorescence-microscopy analyses, IGFBP-3 and TGF-β stimulate TβR-V-mediated IRS-2-dependent activation and cytoplasm-to-nucleus translocation of PP2Ac and PP1c, resulting in dephosphorylation of p130/p107 and pRb, respectively, and growth arrest. Small molecule TGF-β enhancers, which potentiate TGF-β growth inhibition by enhancing TβR-I-TβR-II-mediated canonical signaling and thus activating TβR-V-mediated tumor suppressor signaling cascade (TβR-V/IRS-2/PP1/pRb), could be used to prevent and treat carcinoma.
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Affiliation(s)
- Chun‐Lin Chen
- Department of Biological ScienceNational Sun Yat‐sen UniversityKaohsiungTaiwan
- Departments of Biochemistry and Molecular BiologySaint Louis University School of MedicineSt. LouisMOUSA
| | - Franklin W. Huang
- Division of Hematology and OncologyDepartment of MedicineUniversity of CaliforniaSan FranciscoCAUSA
| | | | - Jung San Huang
- Departments of Biochemistry and Molecular BiologySaint Louis University School of MedicineSt. LouisMOUSA
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10
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De Jamblinne CV, Decelle B, Dehghani M, Joseph M, Sriskandarajah N, Leguay K, Rambaud B, Lemieux S, Roux PP, Hipfner DR, Carréno S. STRIPAK regulates Slik localization to control mitotic morphogenesis and epithelial integrity. J Cell Biol 2021; 219:152107. [PMID: 32960945 PMCID: PMC7594492 DOI: 10.1083/jcb.201911035] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 07/17/2020] [Accepted: 08/20/2020] [Indexed: 02/01/2023] Open
Abstract
Proteins of the ezrin, radixin, and moesin (ERM) family control cell and tissue morphogenesis. We previously reported that moesin, the only ERM in Drosophila, controls mitotic morphogenesis and epithelial integrity. We also found that the Pp1-87B phosphatase dephosphorylates moesin, counteracting its activation by the Ste20-like kinase Slik. To understand how this signaling pathway is itself regulated, we conducted a genome-wide RNAi screen, looking for new regulators of moesin activity. We identified that Slik is a new member of the striatin-interacting phosphatase and kinase complex (STRIPAK). We discovered that the phosphatase activity of STRIPAK reduces Slik phosphorylation to promote its cortical association and proper activation of moesin. Consistent with this finding, inhibition of STRIPAK phosphatase activity causes cell morphology defects in mitosis and impairs epithelial tissue integrity. Our results implicate the Slik–STRIPAK complex in the control of multiple morphogenetic processes.
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Affiliation(s)
- Camille Valérie De Jamblinne
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada.,Programmes de biologie moléculaire, Université de Montréal, Montréal, Quebec, Canada
| | - Barbara Decelle
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada
| | - Mehrnoush Dehghani
- Institut de recherches cliniques de Montréal, Montréal, Quebec, Canada.,Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada
| | - Mathieu Joseph
- Institut de recherches cliniques de Montréal, Montréal, Quebec, Canada.,Programmes de biologie moléculaire, Université de Montréal, Montréal, Quebec, Canada
| | - Neera Sriskandarajah
- Institut de recherches cliniques de Montréal, Montréal, Quebec, Canada.,Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada
| | - Kévin Leguay
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada.,Programmes de biologie moléculaire, Université de Montréal, Montréal, Quebec, Canada
| | - Basile Rambaud
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada.,Programmes de biologie moléculaire, Université de Montréal, Montréal, Quebec, Canada
| | - Sébastien Lemieux
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada.,Département de Biochimie, Université de Montréal, Montréal, Quebec, Canada
| | - Philippe P Roux
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada.,Programmes de biologie moléculaire, Université de Montréal, Montréal, Quebec, Canada.,Département de Pathologie et de Biologie Cellulaire, Université de Montréal, Montréal, Quebec, Canada
| | - David R Hipfner
- Institut de recherches cliniques de Montréal, Montréal, Quebec, Canada.,Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada.,Programmes de biologie moléculaire, Université de Montréal, Montréal, Quebec, Canada.,Département de Médecine, Université de Montréal, Montréal, Quebec, Canada
| | - Sébastien Carréno
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada.,Programmes de biologie moléculaire, Université de Montréal, Montréal, Quebec, Canada.,Département de Pathologie et de Biologie Cellulaire, Université de Montréal, Montréal, Quebec, Canada
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11
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Abstract
The stereotype of ROS produced by NADPH oxidases as cause of malignant diseases persists in a generalized manner. In fact, high levels of ROS formation could be harmful in the context of a disease process. This study demonstrates that loss of the NADPH oxidase Nox4, as a constitutive source of ROS, promotes cancerogen-induced formation of solid tumors. Accordingly, a certain tonic, constitutive low level of Nox4-derived hydrogen peroxide appears to reduce the risk of cancerogen-induced tumor formation. Reactive oxygen species (ROS) can cause cellular damage and promote cancer development. Besides such harmful consequences of overproduction of ROS, all cells utilize ROS for signaling purposes and stabilization of cell homeostasis. In particular, the latter is supported by the NADPH oxidase 4 (Nox4) that constitutively produces low amounts of H2O2. By that mechanism, Nox4 forces differentiation of cells and prevents inflammation. We hypothesize a constitutive low level of H2O2 maintains basal activity of cellular surveillance systems and is unlikely to be cancerogenic. Utilizing two different murine models of cancerogen-induced solid tumors, we found that deletion of Nox4 promotes tumor formation and lowers recognition of DNA damage. Nox4 supports phosphorylation of H2AX (γH2AX), a prerequisite of DNA damage recognition, by retaining a sufficiently low abundance of the phosphatase PP2A in the nucleus. The underlying mechanism is continuous oxidation of AKT by Nox4. Interaction of oxidized AKT and PP2A captures the phosphatase in the cytosol. Absence of Nox4 facilitates nuclear PP2A translocation and dephosphorylation of γH2AX. Simultaneously AKT is left phosphorylated. Thus, in the absence of Nox4, DNA damage is not recognized and the increased activity of AKT supports proliferation. The combination of both events results in genomic instability and promotes tumor formation. By identifying Nox4 as a protective source of ROS in cancerogen-induced cancer, we provide a piece of knowledge for understanding the role of moderate production of ROS in preventing the initiation of malignancies.
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12
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Patt M, Gysi J, Faresse N, Cidlowski JA, Odermatt A. Protein phosphatase 1 alpha enhances glucocorticoid receptor activity by a mechanism involving phosphorylation of serine-211. Mol Cell Endocrinol 2020; 518:110873. [PMID: 32585168 PMCID: PMC7606615 DOI: 10.1016/j.mce.2020.110873] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 04/17/2020] [Accepted: 05/18/2020] [Indexed: 10/24/2022]
Abstract
By acting as a ligand-dependent transcription factor the glucocorticoid receptor (GR) mediates the actions of glucocorticoids and regulates many physiological processes. An impaired regulation of glucocorticoid action has been associated with numerous disorders. Thus, the elucidation of underlying signaling pathways is essential to understand mechanisms of disrupted glucocorticoid function and contribution to diseases. This study found increased GR transcriptional activity upon overexpression of protein phosphatase 1 alpha (PP1α) in HEK-293 cells and decreased expression levels of GR-responsive genes following PP1α knockdown in the endogenous A549 cell model. Mechanistic investigations revealed reduced phosphorylation of GR-Ser211 following PP1α silencing and provided a first indication for an involvement of glycogen synthase kinase 3 (GSK-3). Thus, the present study identified PP1α as a novel post-translational activator of GR signaling, suggesting that disruption of PP1α function could lead to impaired glucocorticoid action and thereby contribute to diseases.
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Affiliation(s)
- Melanie Patt
- Swiss Centre for Applied Human Toxicology (SCAHT), University of Basel, Missionsstrasse 64, 4055, Basel, Switzerland; Division of Molecular and Systems Toxicology, Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland.
| | - Joël Gysi
- Division of Molecular and Systems Toxicology, Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland.
| | | | - John A Cidlowski
- Signal Transduction Laboratory, NIEHS, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, 27709, USA.
| | - Alex Odermatt
- Swiss Centre for Applied Human Toxicology (SCAHT), University of Basel, Missionsstrasse 64, 4055, Basel, Switzerland; Division of Molecular and Systems Toxicology, Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland.
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13
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Huang KL, Jee D, Stein CB, Elrod ND, Henriques T, Mascibroda LG, Baillat D, Russell WK, Adelman K, Wagner EJ. Integrator Recruits Protein Phosphatase 2A to Prevent Pause Release and Facilitate Transcription Termination. Mol Cell 2020; 80:345-358.e9. [PMID: 32966759 PMCID: PMC7660970 DOI: 10.1016/j.molcel.2020.08.016] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/29/2020] [Accepted: 08/24/2020] [Indexed: 12/19/2022]
Abstract
Efficient release of promoter-proximally paused RNA Pol II into productive elongation is essential for gene expression. Recently, we reported that the Integrator complex can bind paused RNA Pol II and drive premature transcription termination, potently attenuating the activity of target genes. Premature termination requires RNA cleavage by the endonuclease subunit of Integrator, but the roles of other Integrator subunits in gene regulation have yet to be elucidated. Here we report that Integrator subunit 8 (IntS8) is critical for transcription repression and required for association with protein phosphatase 2A (PP2A). We find that Integrator-bound PP2A dephosphorylates the RNA Pol II C-terminal domain and Spt5, preventing the transition to productive elongation. Thus, blocking PP2A association with Integrator stimulates pause release and gene activity. These results reveal a second catalytic function associated with Integrator-mediated transcription termination and indicate that control of productive elongation involves active competition between transcriptional kinases and phosphatases.
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Affiliation(s)
- Kai-Lieh Huang
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, TX 77550, USA
| | - David Jee
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Chad B Stein
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Nathan D Elrod
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, TX 77550, USA
| | - Telmo Henriques
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Lauren G Mascibroda
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, TX 77550, USA
| | - David Baillat
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, TX 77550, USA
| | - William K Russell
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, TX 77550, USA
| | - Karen Adelman
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
| | - Eric J Wagner
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, TX 77550, USA.
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14
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Luong NC, Abiko Y, Shibata T, Uchida K, Warabi E, Suzuki M, Noguchi T, Matsuzawa A, Kumagai Y. Redox cycling of 9,10-phenanthrenequinone activates epidermal growth factor receptor signaling through S-oxidation of protein tyrosine phosphatase 1B. J Toxicol Sci 2020; 45:349-363. [PMID: 32493877 DOI: 10.2131/jts.45.349] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
9,10-Phenanthrenequinone (9,10-PQ) is a polycyclic aromatic hydrocarbon quinone contaminated in diesel exhaust particles and particulate matter 2.5. It is an efficient electron acceptor that induces redox cycling with electron donors, resulting in excessive reactive oxygen species and oxidized protein production in cells. The current study examined whether 9,10-PQ could activate epidermal growth factor receptor (EGFR) signaling in A431 cells through S-oxidation of its negative regulators such as protein tyrosine phosphatase (PTP) 1B. 9,10-PQ oxidized recombinant human PTP1B at Cys215 and inhibited its catalytic activity, an effect that was blocked by catalase (CAT), whereas cis-9,10-dihydroxy-9,10-dihydrophenanthrene (DDP), which lacks redox cycling activity, had no effect on PTP1B activity. Exposure of A431 cells to 9,10-PQ, but not DDP, activated signaling through EGFR and its downstream extracellular signal-regulated kinase 1/2 (ERK1/2), coupled with a decrease of cellular PTP activity. Immunoprecipitation and UPLC-MSE revealed that PTP1B easily undergoes oxidation during exposure of A431 cells to 9,10-PQ. Pretreatment with polyethylene glycol conjugated with CAT (PEG-CAT) abolished 9,10-PQ-generated H2O2 production and significantly blocked the activation of EGFR-ERK1/2 signaling by 9,10-PQ, indicating the involvement of H2O2 in the activation because scavenging agents for hydroxyl radicals had no effect on the redox signal activation. These results suggest that such an air pollutant producing H2O2, activates EGFR-ERK1/2 signaling, presumably through the S-oxidation of PTPs such as PTP1B, and activation of the signal cascade may contribute, at least in part, to cellular responses in A431 cells.
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Affiliation(s)
- Nho Cong Luong
- Doctoral Program in Biomedical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba.,Faculty of Pharmacy, Hue University of Medicine and Pharmacy, Hue University, Vietnam
| | - Yumi Abiko
- Doctoral Program in Biomedical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba.,Faculty of Medicine, University of Tsukuba
| | | | - Koji Uchida
- Graduate School of Bioagricultural Sciences, Nagoya University.,Graduate School of Agricultural and Life Sciences, The University of Tokyo
| | - Eiji Warabi
- Doctoral Program in Biomedical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba.,Faculty of Medicine, University of Tsukuba
| | - Midori Suzuki
- Graduate School of Pharmaceutical Sciences, Tohoku University
| | - Takuya Noguchi
- Graduate School of Pharmaceutical Sciences, Tohoku University
| | | | - Yoshito Kumagai
- Doctoral Program in Biomedical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba.,Faculty of Medicine, University of Tsukuba
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15
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Agonist-induced phosphorylation bar code and differential post-activation signaling of the delta opioid receptor revealed by phosphosite-specific antibodies. Sci Rep 2020; 10:8585. [PMID: 32444688 PMCID: PMC7244497 DOI: 10.1038/s41598-020-65589-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 05/05/2020] [Indexed: 01/08/2023] Open
Abstract
The δ-opioid receptor (DOP) is an attractive pharmacological target due to its potent analgesic, anxiolytic and anti-depressant activity in chronic pain models. However, some but not all selective DOP agonists also produce severe adverse effects such as seizures. Thus, the development of novel agonists requires a profound understanding of their effects on DOP phosphorylation, post-activation signaling and dephosphorylation. Here we show that agonist-induced DOP phosphorylation at threonine 361 (T361) and serine 363 (S363) proceeds with a temporal hierarchy, with S363 as primary site of phosphorylation. This phosphorylation is mediated by G protein-coupled receptor kinases 2 and 3 (GRK2/3) followed by DOP endocytosis and desensitization. DOP dephosphorylation occurs within minutes and is predominantly mediated by protein phosphatases (PP) 1α and 1β. A comparison of structurally diverse DOP agonists and clinically used opioids demonstrated high correlation between G protein-dependent signaling efficacies and receptor internalization. In vivo, DOP agonists induce receptor phosphorylation in a dose-dependent and agonist-selective manner that could be blocked by naltrexone in DOP-eGFP mice. Together, our studies provide novel tools and insights for ligand-activated DOP signaling in vitro and in vivo and suggest that DOP agonist efficacies may determine receptor post-activation signaling.
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16
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Svarcbahs R, Jäntti M, Kilpeläinen T, Julku UH, Urvas L, Kivioja S, Norrbacka S, Myöhänen TT. Prolyl oligopeptidase inhibition activates autophagy via protein phosphatase 2A. Pharmacol Res 2019; 151:104558. [PMID: 31759088 DOI: 10.1016/j.phrs.2019.104558] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 11/02/2019] [Accepted: 11/19/2019] [Indexed: 02/06/2023]
Abstract
Prolyl oligopeptidase (PREP) is a serine protease that has been studied particularly in the context of neurodegenerative diseases for decades but its physiological function has remained unclear. We have previously found that PREP negatively regulates beclin1-mediated macroautophagy (autophagy), and that PREP inhibition by a small-molecule inhibitor induces clearance of protein aggregates in Parkinson's disease models. Since autophagy induction has been suggested as a potential therapy for several diseases, we wanted to further characterize how PREP regulates autophagy. We measured the levels of various kinases and proteins regulating beclin1-autophagy in HEK-293 and SH-SY5Y cell cultures after PREP inhibition, PREP deletion, and PREP overexpression and restoration, and verified the results in vivo by using PREP knock-out and wild-type mouse tissue where PREP was restored or overexpressed, respectively. We found that PREP regulates autophagy by interacting with protein phosphatase 2A (PP2A) and its endogenous inhibitor, protein phosphatase methylesterase 1 (PME1), and activator (protein phosphatase 2 phosphatase activator, PTPA), thus adjusting its activity and the levels of PP2A in the intracellular pool. PREP inhibition and deletion increased PP2A activity, leading to activation of death-associated protein kinase 1 (DAPK1), beclin1 phosphorylation and induced autophagy while PREP overexpression reduced this. Lowered activity of PP2A is connected to several neurodegenerative disorders and cancers, and PP2A activators would have enormous potential as drug therapy but development of such compounds has been a challenge. The concept of PREP inhibition has been proved safe, and therefore, our study supports the further development of PREP inhibitors as PP2A activators.
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Affiliation(s)
- Reinis Svarcbahs
- Division of Pharmacology and Pharmacotherapy/Drug Research Program, Faculty of Pharmacy, University of Helsinki, Finland
| | - Maria Jäntti
- Division of Pharmacology and Pharmacotherapy/Drug Research Program, Faculty of Pharmacy, University of Helsinki, Finland
| | - Tommi Kilpeläinen
- Division of Pharmacology and Pharmacotherapy/Drug Research Program, Faculty of Pharmacy, University of Helsinki, Finland
| | - Ulrika H Julku
- Division of Pharmacology and Pharmacotherapy/Drug Research Program, Faculty of Pharmacy, University of Helsinki, Finland
| | - Lauri Urvas
- Division of Pharmacology and Pharmacotherapy/Drug Research Program, Faculty of Pharmacy, University of Helsinki, Finland
| | - Saara Kivioja
- Division of Pharmacology and Pharmacotherapy/Drug Research Program, Faculty of Pharmacy, University of Helsinki, Finland
| | - Susanna Norrbacka
- Division of Pharmacology and Pharmacotherapy/Drug Research Program, Faculty of Pharmacy, University of Helsinki, Finland
| | - Timo T Myöhänen
- Division of Pharmacology and Pharmacotherapy/Drug Research Program, Faculty of Pharmacy, University of Helsinki, Finland.
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17
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Ufd1 phosphorylation at serine 229 negatively regulates endoplasmic reticulum-associated degradation by inhibiting the interaction of Ufd1 with VCP. Biochem J 2019; 476:2561-2577. [PMID: 31477623 DOI: 10.1042/bcj20190254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 08/29/2019] [Accepted: 08/30/2019] [Indexed: 11/17/2022]
Abstract
Misfolded proteins in the endoplasmic reticulum (ER) are removed through multistep processes termed ER-associated degradation (ERAD). Valosin-containing protein (VCP) plays a crucial role in ERAD as the interaction of ubiquitin fusion degradation protein 1 (Ufd1) with VCP via its SHP box motif (228F-S-G-S-G-N-R-L235) is required for ERAD. However, the mechanisms by which the VCP-Ufd1 interaction is regulated are not well understood. Here, we found that the serine 229 residue located in the Ufd1 SHP box is phosphorylated in vitro and in vivo by cyclic adenosine monophosphate-dependent protein kinase A (PKA), with this process being enhanced by either forskolin (an adenylyl cyclase activator) or calyculin A (a protein phosphatase inhibitor). Moreover, a phosphomimetic mutant (S229D) of Ufd1 as well as treatment by forskolin, calyculin A, or activated PKA strongly reduced Ufd1 binding affinity for VCP. Consistent with this, the Ufd1 S229D mutant significantly inhibited ERAD leading to the accumulation of ERAD substrates such as a tyrosinase mutant (C89R) and 3-hydroxy-3-methylglutaryl coenzyme A reductase. However, a non-phosphorylatable Ufd1 mutant (S229A) retained VCP-binding ability and was less effective in blocking ERAD. Collectively, our results support that Ufd1 S229 phosphorylation status mediated by PKA serves as a key regulatory point for the VCP-Ufd1 interaction and functional ERAD.
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18
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Shi X, von Weltin E, Barr JL, Unterwald EM. Activation of GSK3β induced by recall of cocaine reward memories is dependent on GluN2A/B NMDA receptor signaling. J Neurochem 2019; 151:91-102. [PMID: 31361029 DOI: 10.1111/jnc.14842] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 06/21/2019] [Accepted: 07/26/2019] [Indexed: 12/11/2022]
Abstract
Glycogen synthase kinase-3β (GSK3β) is a critical regulator of the balance between long-term depression and long-term potentiation which is essential for learning and memory. Our previous study demonstrated that GSK3β activity is highly induced during cocaine memory reactivation, and that reconsolidation of cocaine reward memory is attenuated by inhibition of GSK3β. NMDA receptors and protein phosphatase 1 (PP1) are activators of GSK3β. Thus, this study investigated the roles of NMDA receptor subtypes and PP1in the reconsolidation of cocaine contextual reward memory. Cocaine contextual memories were established and evaluated using cocaine conditioned place preference methods. The regulation of GSK3β activity in specific brain areas was assessed by measuring its phosphorylation state using immunoblot assays. Mice underwent cocaine place conditioning for 8 days and were tested for place preference on day 9. Twenty-four hours later, mice were briefly confined to the compartment previous paired with cocaine to reactivate cocaine-associated memories. Administration of the GluN2A- and GluN2B-NMDA receptor antagonists, NVP-AAM077 and ifenprodil, respectively, immediately following recall abrogated an established cocaine place preference, while preventing the activation of GSK3β in the amygdala, nucleus accumbens, and hippocampus during cocaine memory reactivation. PP1 inhibition with okadaic acid also blocked the activation of GSK3β and attenuated a previously established cocaine place preference. These findings suggest that the dephosphorylation of GSK3β that occurred upon activation of cocaine-associated reward memories may be initiated by the activation of PP1 during the induction of NMDA receptor-dependent reconsolidation of cocaine mnemonic traces. Moreover, the importance of NMDA receptors and PP1 in reconsolidation of cocaine memory makes them potential therapeutic targets in treatment of cocaine use disorder and prevention of relapse.
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Affiliation(s)
- Xiangdang Shi
- Center for Substance Abuse Research and Department of Pharmacology, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Eva von Weltin
- Center for Substance Abuse Research and Department of Pharmacology, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Jeffrey L Barr
- Center for Substance Abuse Research and Department of Pharmacology, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Ellen M Unterwald
- Center for Substance Abuse Research and Department of Pharmacology, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
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19
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Lee C, Chang W, Chang Y, Yang J, Chang C, Hsu K, Chen Y, Liu T, Chen Y, Lin S, Wu Y, Chang J. Alternative splicing in human cancer cells is modulated by the amiloride derivative 3,5-diamino-6-chloro-N-(N-(2,6-dichlorobenzoyl)carbamimidoyl)pyrazine-2-carboxide. Mol Oncol 2019; 13:1744-1762. [PMID: 31152681 PMCID: PMC6670021 DOI: 10.1002/1878-0261.12524] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 04/30/2019] [Accepted: 05/30/2019] [Indexed: 12/11/2022] Open
Abstract
Alternative splicing (AS) is a process that enables the generation of multiple protein isoforms with different biological properties from a single mRNA. Cancer cells often use the maneuverability conferred by AS to produce proteins that contribute to growth and survival. In our previous studies, we identified that amiloride modulates AS in cancer cells. However, the effective concentration of amiloride required to modulate AS is too high for use in cancer treatment. In this study, we used computational algorithms to screen potential amiloride derivatives for their ability to regulate AS in cancer cells. We found that 3,5-diamino-6-chloro-N-(N-(2,6-dichlorobenzoyl)carbamimidoyl)pyrazine-2-carboxamide (BS008) can regulate AS of apoptotic gene transcripts, including HIPK3, SMAC, and BCL-X, at a lower concentration than amiloride. This splicing regulation involved various splicing factors, and it was accompanied by a change in the phosphorylation state of serine/arginine-rich proteins (SR proteins). RNA sequencing was performed to reveal that AS of many other apoptotic gene transcripts, such as AATF, ATM, AIFM1, NFKB1, and API5, was also modulated by BS008. In vivo experiments further indicated that treatment of tumor-bearing mice with BS008 resulted in a marked decrease in tumor size. BS008 also had inhibitory effects in vitro, either alone or in a synergistic combination with the cytotoxic chemotherapeutic agents sorafenib and nilotinib. BS008 enabled sorafenib dose reduction without compromising antitumor activity. These findings suggest that BS008 may possess therapeutic potential for cancer treatment.
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Affiliation(s)
- Chien‐Chin Lee
- Epigenome Research CenterChina Medical University HospitalTaichungTaiwan
| | - Wen‐Hsin Chang
- Epigenome Research CenterChina Medical University HospitalTaichungTaiwan
- Department of Primary Care MedicineTaipei Medical University HospitalTaiwan
| | - Ya‐Sian Chang
- Epigenome Research CenterChina Medical University HospitalTaichungTaiwan
- Department of Laboratory MedicineChina Medical University HospitalTaichungTaiwan
- Center for Precision MedicineChina Medical University HospitalTaichungTaiwan
| | - Jinn‐Moon Yang
- TIGP‐BioinformaticsInstitute of Information ScienceAcademia SinicaTaipeiTaiwan
- Institute of Bioinformatics and Systems BiologyNational Chiao Tung UniversityHsinchuTaiwan
- Department of Biological Science and TechnologyNational Chiao Tung UniversityHsinchuTaiwan
| | - Chih‐Shiang Chang
- Graduate Institute of Pharmaceutical ChemistryChina Medical UniversityTaichungTaiwan
| | - Kai‐Cheng Hsu
- Graduate Institute of Cancer Molecular Biology and Drug DiscoveryCollege of Medical Science and TechnologyTaipei Medical UniversityTaiwan
| | - Yun‐Ti Chen
- Institute of Bioinformatics and Systems BiologyNational Chiao Tung UniversityHsinchuTaiwan
| | - Ting‐Yuan Liu
- Department of Laboratory MedicineChina Medical University HospitalTaichungTaiwan
| | - Yu‐Chia Chen
- Department of Laboratory MedicineChina Medical University HospitalTaichungTaiwan
| | - Shyr‐Yi Lin
- Department of Primary Care MedicineTaipei Medical University HospitalTaiwan
- Department of General MedicineSchool of MedicineCollege of MedicineTaipei Medical UniversityTaiwan
- TMU Research Center of Cancer Translational MedicineTaipei Medical UniversityTaiwan
| | - Yang‐Chang Wu
- Graduate Institute of Natural ProductsKaohsiung Medical UniversityTaiwan
- Research Center for Natural Products and Drug DevelopmentKaohsiung Medical UniversityTaiwan
- Department of Medical ResearchKaohsiung Medical University HospitalTaiwan
- Chinese Medicine Research and Development CenterChina Medical University HospitalTaichungTaiwan
| | - Jan‐Gowth Chang
- Epigenome Research CenterChina Medical University HospitalTaichungTaiwan
- Department of Primary Care MedicineTaipei Medical University HospitalTaiwan
- Department of Laboratory MedicineChina Medical University HospitalTaichungTaiwan
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20
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Muscarinic acetylcholine receptors regulate the dephosphorylation of eukaryotic translation elongation factor 2 in SNU-407 colon cancer cells. Biochem Biophys Res Commun 2019; 516:424-429. [PMID: 31227218 DOI: 10.1016/j.bbrc.2019.06.059] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 06/11/2019] [Indexed: 11/21/2022]
Abstract
Previously, we showed that muscarinic acetylcholine receptors (mAChRs) promote global protein biosynthesis in SNU-407 colon cancer cells. However, the molecular mechanisms underlying this event are poorly understood. Here, we asked whether mAChRs modulate the activity of eukaryotic translation elongation factor 2 (eEF2), which controls ribosomal translocation during the peptide elongation step. When SNU-407 cells were treated with the cholinergic agonist carbachol, eEF2 phosphorylation at T56 was decreased in a dose- and time-dependent manner. The muscarinic antagonist atropine almost completely blocked this effect of carbachol, demonstrating that mAChRs specifically regulate eEF2 dephosphorylation. We also investigated the signaling pathways that connect mAChR stimulation to eEF2 dephosphorylation using chemical inhibitors. Treating cells with U0126, a potent MEK1/2 inhibitor, decreased carbachol-stimulated eEF2 dephosphorylation. In contrast, the mTORC1 inhibitor rapamycin did not have a significant effect on eEF2 dephosphorylation. We also found that the protein kinase C (PKC) inhibitor GF109203X substantially reduced eEF2 dephosphorylation. Together, our experimental data indicate that the MEK1/2-ERK1/2 pathway and the PKC pathway, but not the mTORC1-S6K1 pathway, are involved in mAChR-mediated eEF2 dephosphorylation.
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21
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Umesalma S, Kaemmer CA, Kohlmeyer JL, Letney B, Schab AM, Reilly JA, Sheehy RM, Hagen J, Tiwari N, Zhan F, Leidinger MR, O'Dorisio TM, Dillon J, Merrill RA, Meyerholz DK, Perl AL, Brown BJ, Braun TA, Scott AT, Ginader T, Taghiyev AF, Zamba GK, Howe JR, Strack S, Bellizzi AM, Narla G, Darbro BW, Quelle FW, Quelle DE. RABL6A inhibits tumor-suppressive PP2A/AKT signaling to drive pancreatic neuroendocrine tumor growth. J Clin Invest 2019; 129:1641-1653. [PMID: 30721156 DOI: 10.1172/jci123049] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 01/24/2019] [Indexed: 12/15/2022] Open
Abstract
Hyperactivated AKT/mTOR signaling is a hallmark of pancreatic neuroendocrine tumors (PNETs). Drugs targeting this pathway are used clinically, but tumor resistance invariably develops. A better understanding of factors regulating AKT/mTOR signaling and PNET pathogenesis is needed to improve current therapies. We discovered that RABL6A, a new oncogenic driver of PNET proliferation, is required for AKT activity. Silencing RABL6A caused PNET cell-cycle arrest that coincided with selective loss of AKT-S473 (not T308) phosphorylation and AKT/mTOR inactivation. Restoration of AKT phosphorylation rescued the G1 phase block triggered by RABL6A silencing. Mechanistically, loss of AKT-S473 phosphorylation in RABL6A-depleted cells was the result of increased protein phosphatase 2A (PP2A) activity. Inhibition of PP2A restored phosphorylation of AKT-S473 in RABL6A-depleted cells, whereas PP2A reactivation using a specific small-molecule activator of PP2A (SMAP) abolished that phosphorylation. Moreover, SMAP treatment effectively killed PNET cells in a RABL6A-dependent manner and suppressed PNET growth in vivo. The present work identifies RABL6A as a new inhibitor of the PP2A tumor suppressor and an essential activator of AKT in PNET cells. Our findings offer what we believe is a novel strategy of PP2A reactivation for treatment of PNETs as well as other human cancers driven by RABL6A overexpression and PP2A inactivation.
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Affiliation(s)
| | | | | | | | | | | | - Ryan M Sheehy
- Department of Pharmacology.,Free Radical & Radiation Biology Training Program
| | | | | | | | - Mariah R Leidinger
- Department of Pathology, in the College of Medicine, Holden Comprehensive Cancer Center, University of Iowa, Iowa City, Iowa, USA
| | | | | | | | - David K Meyerholz
- Department of Pathology, in the College of Medicine, Holden Comprehensive Cancer Center, University of Iowa, Iowa City, Iowa, USA
| | - Abbey L Perl
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, USA
| | | | | | | | | | - Agshin F Taghiyev
- Pediatrics, Colleges of Medicine, Engineering, or Public Health, University of Iowa, Iowa City, Iowa, USA
| | | | | | | | - Andrew M Bellizzi
- Department of Pathology, in the College of Medicine, Holden Comprehensive Cancer Center, University of Iowa, Iowa City, Iowa, USA
| | - Goutham Narla
- Department of Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Benjamin W Darbro
- Pediatrics, Colleges of Medicine, Engineering, or Public Health, University of Iowa, Iowa City, Iowa, USA
| | | | - Dawn E Quelle
- Department of Pharmacology.,Molecular Medicine Graduate Program.,Free Radical & Radiation Biology Training Program.,Department of Pathology, in the College of Medicine, Holden Comprehensive Cancer Center, University of Iowa, Iowa City, Iowa, USA
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22
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Kubiniok P, Finicle BT, Piffaretti F, McCracken AN, Perryman M, Hanessian S, Edinger AL, Thibault P. Dynamic Phosphoproteomics Uncovers Signaling Pathways Modulated by Anti-oncogenic Sphingolipid Analogs. Mol Cell Proteomics 2019; 18:408-422. [PMID: 30482847 PMCID: PMC6398214 DOI: 10.1074/mcp.ra118.001053] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 10/23/2018] [Indexed: 12/31/2022] Open
Abstract
The anti-neoplastic sphingolipid analog SH-BC-893 starves cancer cells to death by down-regulating cell surface nutrient transporters and blocking lysosomal trafficking events. These effects are mediated by the activation of protein phosphatase 2A (PP2A). To identify putative PP2A substrates, we used quantitative phosphoproteomics to profile the temporal changes in protein phosphorylation in FL5.12 cells following incubation with SH-BC-893 or the specific PP2A inhibitor LB-100. These analyses enabled the profiling of more than 15,000 phosphorylation sites, of which 958 sites on 644 proteins were dynamically regulated. We identified 114 putative PP2A substrates including several nutrient transporter proteins, GTPase regulators (e.g. Agap2, Git1), and proteins associated with actin cytoskeletal remodeling (e.g. Vim, Pxn). To identify SH-BC-893-induced cell signaling events that disrupt lysosomal trafficking, we compared phosphorylation profiles in cells treated with SH-BC-893 or C2-ceramide, a non-vacuolating sphingolipid that does not impair lysosomal fusion. These analyses combined with functional assays uncovered the differential regulation of Akt and Gsk3b by SH-BC-893 (vacuolating) and C2-ceramide (non-vacuolating). Dynamic phosphoproteomics of cells treated with compounds affecting PP2A activity thus enabled the correlation of cell signaling with phenotypes to rationalize their mode of action.
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Affiliation(s)
- Peter Kubiniok
- From the ‡Institute for Research in Immunology and Cancer, Université de Montréal, C.P. 6128, Succursale centre-ville, Montréal, Québec, H3C 3J7, Canada
- §Department of Chemistry, Université de Montréal, Quebec, H3C 3J7, Canada
| | - Brendan T Finicle
- ¶Department of Developmental and Cell Biology, University of California Irvine, Irvine CA 92697
| | - Fanny Piffaretti
- From the ‡Institute for Research in Immunology and Cancer, Université de Montréal, C.P. 6128, Succursale centre-ville, Montréal, Québec, H3C 3J7, Canada
| | - Alison N McCracken
- ¶Department of Developmental and Cell Biology, University of California Irvine, Irvine CA 92697
| | - Michael Perryman
- §Department of Chemistry, Université de Montréal, Quebec, H3C 3J7, Canada
| | - Stephen Hanessian
- §Department of Chemistry, Université de Montréal, Quebec, H3C 3J7, Canada
| | - Aimee L Edinger
- ¶Department of Developmental and Cell Biology, University of California Irvine, Irvine CA 92697;
| | - Pierre Thibault
- From the ‡Institute for Research in Immunology and Cancer, Université de Montréal, C.P. 6128, Succursale centre-ville, Montréal, Québec, H3C 3J7, Canada;
- §Department of Chemistry, Université de Montréal, Quebec, H3C 3J7, Canada
- ‖Department of Biochemistry, Université de Montréal, C.P. 6128, Succursale centre-ville, Montréal, Québec, H3C 3J7, Canada
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23
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Wang J, Chan B, Tong M, Paung Y, Jo U, Martin D, Seeliger M, Haley J, Kim H. Prolyl isomerization of FAAP20 catalyzed by PIN1 regulates the Fanconi anemia pathway. PLoS Genet 2019; 15:e1007983. [PMID: 30789902 PMCID: PMC6400411 DOI: 10.1371/journal.pgen.1007983] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 03/05/2019] [Accepted: 01/23/2019] [Indexed: 01/27/2023] Open
Abstract
The Fanconi Anemia (FA) pathway is a multi-step DNA repair process at stalled replication forks in response to DNA interstrand cross-links (ICLs). Pathological mutation of key FA genes leads to the inherited disorder FA, characterized by progressive bone marrow failure and cancer predisposition. The study of FA is of great importance not only to children suffering from FA but also as a model to study cancer pathogenesis in light of genome instability among the general population. FANCD2 monoubiquitination by the FA core complex is an essential gateway that connects upstream DNA damage signaling to enzymatic steps of repair. FAAP20 is a key component of the FA core complex, and regulated proteolysis of FAAP20 mediated by the ubiquitin E3 ligase SCFFBW7 is critical for maintaining the integrity of the FA complex and FA pathway signaling. However, upstream regulatory mechanisms that govern this signaling remain unclear. Here, we show that PIN1, a phosphorylation-specific prolyl isomerase, regulates the integrity of the FA core complex, thus FA pathway activation. We demonstrate that PIN1 catalyzes cis-trans isomerization of the FAAP20 pSer48-Pro49 motif and promotes FAAP20 stability. Mechanistically, PIN1-induced conformational change of FAAP20 enhances its interaction with the PP2A phosphatase to counteract SCFFBW7-dependent proteolytic signaling at the phosphorylated degron motif. Accordingly, PIN1 deficiency impairs FANCD2 activation and the DNA ICL repair process. Together, our study establishes PIN1-dependent prolyl isomerization as a new regulator of the FA pathway and genomic integrity. Fanconi anemia (FA) is a devastating disease of children that leads to birth defects, bone marrow failure, and a variety of cancers early in their lives. Germ-line mutations in FA genes disrupt the DNA repair process, namely the FA pathway, resulting in genome instability and clinical features of FA patients. Thus, understanding the molecular mechanisms by which the FA pathway is regulated is critical for alleviating the burden of children suffering from FA and related cancer. A critical step in this pathway is the monoubiquitination of FANCD2 by a multi-subunit ubiquitin E3 ligase called the FA core complex, and the FAAP20 subunit is required for its functional integrity. Here, we show that proline-directed structural change of FAAP20 catalyzed by the PIN1 prolyl cis-trans isomerase is essential for the FAAP20 stability by counteracting phosphorylation-dependent proteolytic signaling of FAAP20 and thus promotes FANCD2 activation and DNA repair. Our findings reveal how PIN1-mediated phosphorylation signaling cascade and proteolysis preserves genomic integrity and how its deregulation is associated the pathogenesis of FA. Our knowledge on a new regulatory mechanism governing FA pathway activation may lead to the development of a new target for FA and FA-related malignancy.
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Affiliation(s)
- Jingming Wang
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York, United States of America
| | - Bryan Chan
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York, United States of America
| | - Michael Tong
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York, United States of America
| | - YiTing Paung
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York, United States of America
- Department of Chemistry, Stony Brook University, Stony Brook, New York, United States of America
| | - Ukhyun Jo
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York, United States of America
| | - Dwight Martin
- Department of Pathology, Proteomics Center, Stony Brook University, Stony Brook, New York, United States of America
| | - Markus Seeliger
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York, United States of America
- Stony Brook Cancer Center, Stony Brook University School of Medicine, Stony Brook, New York, United States of America
| | - John Haley
- Department of Pathology, Proteomics Center, Stony Brook University, Stony Brook, New York, United States of America
- Stony Brook Cancer Center, Stony Brook University School of Medicine, Stony Brook, New York, United States of America
| | - Hyungjin Kim
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York, United States of America
- Stony Brook Cancer Center, Stony Brook University School of Medicine, Stony Brook, New York, United States of America
- * E-mail:
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24
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Strang KH, Sorrentino ZA, Riffe CJ, Gorion KMM, Vijayaraghavan N, Golde TE, Giasson BI. Phosphorylation of serine 305 in tau inhibits aggregation. Neurosci Lett 2018; 692:187-192. [PMID: 30423399 DOI: 10.1016/j.neulet.2018.11.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 10/30/2018] [Accepted: 11/06/2018] [Indexed: 11/17/2022]
Abstract
Alzheimer's disease and other tauopathies are characterized by the brain accumulation of hyperphosphorylated aggregated tau protein forming pathological inclusions. Although elevated tau phosphorylated at many amino acid residues is a hallmark of pathological tau, some evidence suggest that tau phosphorylation at unique sites, especially within its microtubule-binding domain, might inhibit aggregation. In this study, the effects of phosphorylation of two unique residues within this domain, serine 305 (S305) and serine 320 (S320), were examined in the context of established aggregation and seeding models. It was found that the S305E phosphomimetic significantly inhibited both tau seeding and tau aggregation in this model, while S320E did not. To further explore S305 phosphorylation in vivo, a monoclonal antibody (2G2) specific for tau phosphorylated at S305 was generated and characterized. Consistent with inhibition of tau aggregation, phosphorylation of S305 was not detected in pathological tau inclusions in Alzheimer's disease brain tissue. This study indicates that phosphorylation of unique tau residues can be inhibitory to aggregate formation, and has important implications for potential kinase therapies. Additionally, it creates new tools for observing these changes in vivo.
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Affiliation(s)
- Kevin H Strang
- Department of Neuroscience, University of Florida, Gainesville, FL 32610, USA; Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL 32610, USA
| | - Zachary A Sorrentino
- Department of Neuroscience, University of Florida, Gainesville, FL 32610, USA; Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL 32610, USA
| | - Cara J Riffe
- Department of Neuroscience, University of Florida, Gainesville, FL 32610, USA; Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL 32610, USA
| | - Kimberly-Marie M Gorion
- Department of Neuroscience, University of Florida, Gainesville, FL 32610, USA; Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL 32610, USA
| | - Niran Vijayaraghavan
- Department of Neuroscience, University of Florida, Gainesville, FL 32610, USA; Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL 32610, USA
| | - Todd E Golde
- Department of Neuroscience, University of Florida, Gainesville, FL 32610, USA; Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL 32610, USA; McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Benoit I Giasson
- Department of Neuroscience, University of Florida, Gainesville, FL 32610, USA; Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL 32610, USA; McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA.
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25
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Soeda S, Yamada-Nomoto K, Michiue T, Ohsugi M. RSK-MASTL Pathway Delays Meiotic Exit in Mouse Zygotes to Ensure Paternal Chromosome Stability. Dev Cell 2018; 47:363-376.e5. [DOI: 10.1016/j.devcel.2018.09.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 06/25/2018] [Accepted: 09/09/2018] [Indexed: 11/30/2022]
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26
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Jia Q, Lin Y, Gou X, He L, Shen D, Chen D, Xie W, Lu Y. Legionella pneumophila effector WipA, a bacterial PPP protein phosphatase with PTP activity. Acta Biochim Biophys Sin (Shanghai) 2018; 50:547-554. [PMID: 29701815 DOI: 10.1093/abbs/gmy042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Indexed: 11/12/2022] Open
Abstract
The gram-negative bacterium Legionella pneumophila invades human's lung and causes Legionnaires' disease. To benefit its survival and replication in cellular milieu, L. pneumophila secrets at least 330 effector proteins into host cells. We found that the effector WipA has the protein tyrosine phosphatase (PTP) activity but does not depend on the classical CX5R motif for activity, suggesting that WipA is an unconventional PTP. Meanwhile, the presence of three other highly conserved motifs typically seen in protein serine/threonine phosphatases and the poor inhibition of WipA activity by okadaic acid led us to propose that WipA is a bacterial protein phosphatase. In addition, the determination of the 2.55-Å crystal structure of WipA revealed that WipA resembles cold-active protein tyrosine phosphatase (CAPTPase), and therefore very likely shares the same catalytic mechanism.
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Affiliation(s)
- Qian Jia
- School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou 510275, China
| | - Yun Lin
- School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
- Biomedical Center of Sun Yat-sen University, Guangzhou 510275, China
| | - Xuejing Gou
- School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
- Biomedical Center of Sun Yat-sen University, Guangzhou 510275, China
| | - Lei He
- School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
- Biomedical Center of Sun Yat-sen University, Guangzhou 510275, China
| | - Dong Shen
- School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
- Biomedical Center of Sun Yat-sen University, Guangzhou 510275, China
| | - Dongni Chen
- School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
- Biomedical Center of Sun Yat-sen University, Guangzhou 510275, China
| | - Wei Xie
- School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou 510275, China
| | - Yongjun Lu
- School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
- Biomedical Center of Sun Yat-sen University, Guangzhou 510275, China
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27
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Dortet L, Lombardi C, Cretin F, Dessen A, Filloux A. Pore-forming activity of the Pseudomonas aeruginosa type III secretion system translocon alters the host epigenome. Nat Microbiol 2018; 3:378-386. [PMID: 29403015 DOI: 10.1038/s41564-018-0109-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 12/21/2017] [Indexed: 12/13/2022]
Abstract
Recent studies highlight that bacterial pathogens can reprogram target cells by influencing epigenetic factors. The type III secretion system (T3SS) is a bacterial nanomachine that resembles a syringe on the bacterial surface. The T3SS 'needle' delivers translocon proteins into eukaryotic cell membranes, subsequently allowing injection of bacterial effectors into the cytosol. Here we show that Pseudomonas aeruginosa induces early T3SS-dependent dephosphorylation and deacetylation of histone H3 in eukaryotic cells. This is not triggered by any of the P. aeruginosa T3SS effectors, but results from the insertion of the PopB-PopD translocon into the membrane. This suggests that the P. aeruginosa translocon is a genuine T3SS effector acting as a pore-forming toxin. We visualized the translocon plugged into the host cell membrane after the bacterium has left the site of contact, and demonstrate that subsequent ion exchange through this pore is responsible for histone H3 modifications and host cell subversion.
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Affiliation(s)
- Laurent Dortet
- MRC Centre for Molecular Microbiology and Infection, Department of Life Sciences, Imperial College London, London, UK.,EA7361 'Structure, dynamic, function and expression of broad spectrum β-lactamases', Faculty of Medicine, Paris-Sud University, LabEx Lermit, Le Kremlin-Bicêtre, France
| | - Charlotte Lombardi
- Institut de Biologie Structurale (IBS), University Grenoble-Alpes, CEA, CNRS, Bacterial Pathogenesis Group, Grenoble, France
| | - François Cretin
- University Grenoble-Alpes, Bacterial Pathogenesis and Cellular Responses, CNRS-ERL5261, U1036_S, INSERM, Biosciences and Biotechnology Institute of Grenoble, CEA-Grenoble, Grenoble, France
| | - Andréa Dessen
- Institut de Biologie Structurale (IBS), University Grenoble-Alpes, CEA, CNRS, Bacterial Pathogenesis Group, Grenoble, France.,Brazilian Biosciences National Laboratory (LNBio), CNPEM, São Paulo, Brazil
| | - Alain Filloux
- MRC Centre for Molecular Microbiology and Infection, Department of Life Sciences, Imperial College London, London, UK.
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28
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Dedigama-Arachchige PM, Acharige NPN, Pflum MKH. Identification of PP1-Gadd34 substrates involved in the unfolded protein response using K-BIPS, a method for phosphatase substrate identification. Mol Omics 2018; 14:121-133. [PMID: 29623310 DOI: 10.1039/c7mo00064b] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Phosphorylation is a key post-translational modification in cell signaling, which is regulated by the equilibrium activities of kinases and phosphatases. The biological significance of many phosphorylation events remains poorly characterized due to the scarcity of tools to discover phosphatases substrates. In prior work, we established kinase-catalyzed biotinylation where kinases accept the γ-modified ATP analog, ATP-biotin, to label phosphoproteins. Here, we developed a novel method to study substrates of phosphatases using kinase-catalyzed biotinylation termed K-BIPS (Kinase-catalyzed Biotinylation to Identify Phosphatase Substrates). In a proof-of-concept experiment, K-BIPS was initially used to explore the substrates of phosphatases inhibited by okadaic acid. Many known phosphatase substrates were observed, confirming K-BIPS as a valid phosphatase substrate identification tool. Then, as a further application, K-BIPS was used to discover the substrates of the PP1-Gadd34 phosphatase complex in the context of unfolded protein response (UPR). In addition to the known substrate eIF2α, K-BIPS revealed several novel substrates, suggesting a more prominent role for the PP1-Gadd34 complex in UPR than previously appreciated. Overall, the two studies establish K-BIPS as a powerful tool to discover the cellular substrates of phosphatases.
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29
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Creighton MT, Kolton A, Kataya ARA, Maple-Grødem J, Averkina IO, Heidari B, Lillo C. Methylation of protein phosphatase 2A-Influence of regulators and environmental stress factors. PLANT, CELL & ENVIRONMENT 2017; 40:2347-2358. [PMID: 28741704 DOI: 10.1111/pce.13038] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 07/08/2017] [Accepted: 07/11/2017] [Indexed: 05/13/2023]
Abstract
Protein phosphatase 2A catalytic subunit (PP2A-C) has a terminal leucine subjected to methylation, a regulatory mechanism conserved from yeast to mammals and plants. Two enzymes, LCMT1 and PME1, methylate and demethylate PP2A-C, respectively. The physiological importance of these posttranslational modifications is still enigmatic. We investigated these processes in Arabidopsis thaliana by mutant phenotyping, by global expression analysis, and by monitoring methylation status of PP2A-C under different environmental conditions. The lcmt1 mutant, possessing essentially only unmethylated PP2A-C, had less dense rosettes, and earlier flowering than wild type (WT). The pme1 mutant, with 30% reduction in unmethylated PP2A-C, was phenotypically comparable with WT. Approximately 200 overlapping genes were twofold upregulated, and 200 overlapping genes were twofold downregulated in both lcmt1 and pme1 relative to WT. Differences between the 2 mutants were also striking; 97 genes were twofold upregulated in pme1 compared with lcmt1, indicating that PME1 acts as a negative regulator for these genes. Analysis of enriched GO terms revealed categories of both abiotic and biotic stress genes. Furthermore, methylation status of PP2A-C was influenced by environmental stress, especially by hypoxia and salt stress, which led to increased levels of unmethylated PP2A-C, and highlights the importance of PP2A-C methylation/demethylation in environmental responses.
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Affiliation(s)
- Maria T Creighton
- Centre for Organelle Research, Faculty of Science and Technology, University of Stavanger, Stavanger, N-4036, Norway
| | - Anna Kolton
- Centre for Organelle Research, Faculty of Science and Technology, University of Stavanger, Stavanger, N-4036, Norway
- Faculty of Biotechnology and Horticulture, University of Agriculture in Krakow, Kraków, 31-425 Kraków, Poland
| | - Amr R A Kataya
- Centre for Organelle Research, Faculty of Science and Technology, University of Stavanger, Stavanger, N-4036, Norway
| | - Jodi Maple-Grødem
- Centre for Organelle Research, Faculty of Science and Technology, University of Stavanger, Stavanger, N-4036, Norway
| | - Irina O Averkina
- Centre for Organelle Research, Faculty of Science and Technology, University of Stavanger, Stavanger, N-4036, Norway
| | - Behzad Heidari
- Centre for Organelle Research, Faculty of Science and Technology, University of Stavanger, Stavanger, N-4036, Norway
| | - Cathrine Lillo
- Centre for Organelle Research, Faculty of Science and Technology, University of Stavanger, Stavanger, N-4036, Norway
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30
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Creighton MT, Sanmartín M, Kataya ARA, Averkina IO, Heidari B, Nemie-Feyissa D, Sánchez-Serrano JJ, Lillo C. Light regulation of nitrate reductase by catalytic subunits of protein phosphatase 2A. PLANTA 2017; 246:701-710. [PMID: 28656346 DOI: 10.1007/s00425-017-2726-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 06/21/2017] [Indexed: 05/26/2023]
Abstract
PP2A catalytic subunit C2 is of special importance for light/dark regulation of nitrate reductase activity. The level of unmethylated PP2A catalytic subunits decreases in darkness. Protein phosphatase 2A (PP2A) dephosphorylates and activates nitrate reductase (NR) in photosynthetically active tissue when plants are transferred from darkness to light. In the present work, investigation of Arabidopsis thaliana PP2A mutant lines revealed that one of the five PP2A catalytic subunit genes, e.g., C2, was of special importance for NR activation. Impairment of NR activation was, especially pronounced in the c2c4 double mutant. Though weaker, NR activation was also impaired in the c2 single mutant, and c1c2 and c2c5 double mutants. On the other hand, NR activation in the c4c5 double mutant was as efficient as in WT. The c4 single mutant had low PP2A activity, whereas the c2 single mutant possessed WT levels of extractable PP2A activity. PP2A activity was low in both c2c4 and c4c5. Differences in extracted PP2A activity among mutants did not strictly correlate with differences in NR activation, but underpinned that C2 has a special function in NR activation in vivo. The terminal leucine in PP2A catalytic subunits is generally methylated to a high degree, but regulation and impact of methylation/demethylation is barely studied. In WT and PP2A mutants, the level of unmethylated PP2A catalytic subunits decreased during 45 min of darkness, but did not change much when light was switched on. In leucine carboxyl methyl transferase1 (LCMT1) knockout plants, which possess mainly unmethylated PP2A, NR was still activated, although not fully as efficient as in WT.
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Affiliation(s)
- Maria T Creighton
- Faculty of Science and Technology, Centre for Organelle Research, University of Stavanger, 4036, Stavanger, Norway
| | - Maite Sanmartín
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología, CSIC, Madrid, Spain
| | - Amr R A Kataya
- Faculty of Science and Technology, Centre for Organelle Research, University of Stavanger, 4036, Stavanger, Norway
| | - Irina O Averkina
- Faculty of Science and Technology, Centre for Organelle Research, University of Stavanger, 4036, Stavanger, Norway
| | - Behzad Heidari
- Faculty of Science and Technology, Centre for Organelle Research, University of Stavanger, 4036, Stavanger, Norway
| | - Dugassa Nemie-Feyissa
- Faculty of Science and Technology, Centre for Organelle Research, University of Stavanger, 4036, Stavanger, Norway
| | - Jose J Sánchez-Serrano
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología, CSIC, Madrid, Spain
| | - Cathrine Lillo
- Faculty of Science and Technology, Centre for Organelle Research, University of Stavanger, 4036, Stavanger, Norway.
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31
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Lier C, Becker S, Biedenkopf N. Dynamic phosphorylation of Ebola virus VP30 in NP-induced inclusion bodies. Virology 2017; 512:39-47. [PMID: 28915404 DOI: 10.1016/j.virol.2017.09.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 08/18/2017] [Accepted: 09/07/2017] [Indexed: 12/22/2022]
Abstract
Zaire Ebolavirus (EBOV) causes a severe feverish disease with high case fatality rates. Transcription of EBOV is dependent on the activity of the nucleocapsid protein VP30 which represents an essential viral transcription factor. Activity of VP30 is regulated via phosphorylation at six N-terminal serine residues. Recent data demonstrated that dynamic phosphorylation and dephosphorylation of serine residue 29 is essential for transcriptional support activity of VP30. To analyze the spatio/temporal dynamics of VP30 phosphorylation, we generated a peptide antibody recognizing specifically VP30 phosphorylated at serine 29. Using this antibody we could demonstrate that (i) the majority of VP30 molecules in EBOV-infected cells is dephosphorylated at the crucial position serine 29, (ii) both, VP30 phosphorylation and dephosphorylation take place in viral inclusion bodies that are induced by the nucleoprotein NP and (iii) NP influences the phosphorylation state of VP30.
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Affiliation(s)
- Clemens Lier
- Institute of Virology, Philipps-University Marburg, Marburg, Germany; German Center of Infection Research (DZIF), Partner Site Giessen-Marburg-Langen, Marburg, Germany
| | - Stephan Becker
- Institute of Virology, Philipps-University Marburg, Marburg, Germany; German Center of Infection Research (DZIF), Partner Site Giessen-Marburg-Langen, Marburg, Germany.
| | - Nadine Biedenkopf
- Institute of Virology, Philipps-University Marburg, Marburg, Germany; German Center of Infection Research (DZIF), Partner Site Giessen-Marburg-Langen, Marburg, Germany.
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32
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Lee CC, Chang WH, Chang YS, Liu TY, Chen YC, Wu YC, Chang JG. 4β-Hydroxywithanolide E Modulates Alternative Splicing of Apoptotic Genes in Human Hepatocellular Carcinoma Huh-7 Cells. Sci Rep 2017; 7:7290. [PMID: 28779122 PMCID: PMC5544667 DOI: 10.1038/s41598-017-07472-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 06/27/2017] [Indexed: 01/31/2023] Open
Abstract
Alternative splicing is a mechanism for increasing protein diversity from a limited number of genes. Studies have demonstrated that aberrant regulation in the alternative splicing of apoptotic gene transcripts may contribute to the development of cancer. In this study, we isolated 4β-Hydroxywithanolide E (4bHWE) from the traditional herb Physalis peruviana and investigated its biological effect in cancer cells. The results demonstrated that 4bHWE modulates the alternative splicing of various apoptotic genes, including HIPK3, SMAC/DIABLO, and SURVIVIN. We also discovered that the levels of SRSF1 phospho-isoform were decreased and the levels of H3K36me3 were increased in 4bHWE treatment. Knockdown experiments revealed that the splicing site selection of SMAC/DIABLO could be mediated by changes in the level of H3K36me3 in 4bHWE-treated cells. Furthermore, we extended our study to apoptosis-associated molecules, and detected increased levels of poly ADP-ribose polymerase cleavage and the active form of CASPASE-3 in 4bHWE-induced apoptosis. In vivo experiments indicated that the treatment of tumor-bearing mice with 4bHWE resulted in a marked decrease in tumor size. This study is the first to demonstrate that 4bHWE affects alternative splicing by modulating splicing factors and histone modifications, and provides a novel view of the antitumor mechanism of 4bHWE.
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Affiliation(s)
- Chien-Chin Lee
- Epigenome Research Center, China Medical University Hospital, Taichung, Taiwan
| | - Wen-Hsin Chang
- Department of Primary Care Medicine, Taipei Medical University Hospital, Taipei, Taiwan
| | - Ya-Sian Chang
- Epigenome Research Center, China Medical University Hospital, Taichung, Taiwan.,Department of Laboratory Medicine, China Medical University Hospital, Taichung, Taiwan.,Center for Precision Medicine, China Medical University Hospital, Taichung, Taiwan
| | - Ting-Yuan Liu
- Center for Precision Medicine, China Medical University Hospital, Taichung, Taiwan
| | - Yu-Chia Chen
- Center for Precision Medicine, China Medical University Hospital, Taichung, Taiwan
| | - Yang-Chang Wu
- Graduate Institute of Natural Products, Kaohsiung Medical University, Kaohsiung, Taiwan. .,Research Center for Natural Products and Drug Development, Kaohsiung Medical University, Kaohsiung, Taiwan. .,Chinese Medicine Research and Development Center, China Medical University Hospital, Taichung, Taiwan.
| | - Jan-Gowth Chang
- Epigenome Research Center, China Medical University Hospital, Taichung, Taiwan. .,Department of Laboratory Medicine, China Medical University Hospital, Taichung, Taiwan. .,Center for Precision Medicine, China Medical University Hospital, Taichung, Taiwan. .,Department of Bioinformatics and Medical Engineering, Asia University, Taichung, Taiwan.
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Preußner M, Goldammer G, Neumann A, Haltenhof T, Rautenstrauch P, Müller-McNicoll M, Heyd F. Body Temperature Cycles Control Rhythmic Alternative Splicing in Mammals. Mol Cell 2017; 67:433-446.e4. [DOI: 10.1016/j.molcel.2017.06.006] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 04/27/2017] [Accepted: 06/07/2017] [Indexed: 12/12/2022]
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Quantitative Phosphoproteomics Reveals a Role for Collapsin Response Mediator Protein 2 in PDGF-Induced Cell Migration. Sci Rep 2017. [PMID: 28638064 PMCID: PMC5479788 DOI: 10.1038/s41598-017-04015-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The Platelet Derived Growth Factor (PDGF) family of ligands have well established functions in the induction of cell proliferation and migration during development, tissue homeostasis and interactions between tumours and stroma. However, the mechanisms by which these actions are executed are incompletely understood. Here we report a differential phosphoproteomics study, using a SILAC approach, of PDGF-stimulated mouse embryonic fibroblasts (MEFs). 116 phospho-sites were identified as up-regulated and 45 down-regulated in response to PDGF stimulation. These encompass proteins involved in cell adhesion, cytoskeleton regulation and vesicle-mediated transport, significantly expanding the range of proteins implicated in PDGF signalling pathways. Included in the down-regulated class was the microtubule bundling protein Collapsin Response Mediator Protein 2 (CRMP2). In response to stimulation with PDGF, CRMP2 was dephosphorylated on Thr514, an event known to increase CRMP2 activity. This was reversed in the presence of micromolar concentrations of the protein phosphatase inhibitor okadaic acid, implicating PDGF-induced activation of protein phosphatase 1 (PP1) in CRMP2 regulation. Depletion of CRMP2 resulted in impairment of PDGF-mediated cell migration in an in vitro wound healing assay. These results show that CRMP2 is required for PDGF-directed cell migration in vitro.
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Chang WH, Niu DM, Lu CY, Lin SY, Liu TC, Chang JG. Modulation the alternative splicing of GLA (IVS4+919G>A) in Fabry disease. PLoS One 2017; 12:e0175929. [PMID: 28430823 PMCID: PMC5400244 DOI: 10.1371/journal.pone.0175929] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 04/03/2017] [Indexed: 12/31/2022] Open
Abstract
While a base substitution in intron 4 of GLA (IVS4+919G>A) that causes aberrant alternative splicing resulting in Fabry disease has been reported, its molecular mechanism remains unclear. Here we reported that upon IVS4+919G>A transversion, H3K36me3 was enriched across the alternatively spliced region. PSIP1, an adapter of H3K36me3, together with Hsp70 and NONO were recruited and formed a complex with SF2/ASF and SRp20, which further promoted GLA splicing. Amiloride, a splicing regulator in cancer cells, could reverse aberrant histone modification patterns and disrupt the association of splicing complex with GLA. It could also reverse aberrant GLA splicing in a PP1-dependant manner. Our findings revealed the alternative splicing mechanism of GLA (IVS4+919G>A), and a potential treatment for this specific genetic type of Fabry disease by amiloride in the future.
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Affiliation(s)
- Wen-Hsin Chang
- Department of Primary Care Medicine, Taipei Medical University Hospital, Taipei, Taiwan
| | - Dau-Ming Niu
- Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan
- Department of Pediatrics, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Chi-Yu Lu
- Department of Biochemistry, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Research Center for Environmental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Shyr-Yi Lin
- Department of Primary Care Medicine, Taipei Medical University Hospital, Taipei, Taiwan
- Department of General Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- * E-mail: (SYL); (TCL); (JGC)
| | - Ta-Chih Liu
- Graduate Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Division of Hematology and Oncology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
- * E-mail: (SYL); (TCL); (JGC)
| | - Jan-Gowth Chang
- Epigenome Research Center, China Medical University Hospital, Taichung, Taiwan
- Department of Laboratory Medicine, China Medical University Hospital, Taichung, Taiwan
- School of Medicine, China Medical University, Taichung, Taiwan
- Department of Bioinformatics and Medical Engineering, Asia University, Taichung, Taiwan
- * E-mail: (SYL); (TCL); (JGC)
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36
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Liu CY, Hsieh FS, Chu PY, Tsai WC, Huang CT, Yu YB, Huang TT, Ko PS, Hung MH, Wang WL, Shiau CW, Chen KF. Carfilzomib induces leukaemia cell apoptosis via inhibiting ELK1/KIAA1524 (Elk-1/CIP2A) and activating PP2A not related to proteasome inhibition. Br J Haematol 2017; 177:726-740. [PMID: 28340282 DOI: 10.1111/bjh.14620] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Accepted: 12/22/2016] [Indexed: 01/23/2023]
Abstract
Enhancing the tumour suppressive activity of protein phosphatase 2A (PP2A) has been suggested to be an anti-leukaemic strategy. KIAA1524 (also termed CIP2A), an oncoprotein inhibiting PP2A, is associated with disease progression in chronic myeloid leukaemia and may be prognostic in cytogenetically normal acute myeloid leukaemia. Here we demonstrated that the selective proteasome inhibitor, carfilzomib, induced apoptosis in sensitive primary leukaemia cells and in sensitive leukaemia cell lines, associated with KIAA1524 protein downregulation, increased PP2A activity and decreased p-Akt, but not with the proteasome inhibition effect of carfilzomib. Ectopic expression of KIAA1524, or pretreatment with the PP2A inhibitor, okadaic acid, suppressed carfilzomib-induced apoptosis and KIAA1524 downregulation in sensitive cells, whereas co-treatment with the PP2A agonist, forskolin, enhanced carfilzomib-induced apoptosis in resistant cells. Mechanistically, carfilzomib affected KIAA1524 transcription through disturbing ELK1 (Elk-1) binding to the KIAA1524 promoter. Moreover, the drug sensitivity and mechanism of carfilzomib in xenograft mouse models correlated well with the effects of carfilzomib on KIAA1524 and p-Akt expression, as well as PP2A activity. Our data disclosed a novel drug mechanism of carfilzomib in leukaemia cells and suggests the potential therapeutic implication of KIAA1524 in leukaemia treatment.
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Affiliation(s)
- Chun-Yu Liu
- Comprehensive Breast Health Centre, Taipei Veterans General Hospital, Taipei, Taiwan.,Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan.,School of Medicine, National Yang-Ming University, Taipei, Taiwan.,Division of Haematology and Oncology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Feng-Shu Hsieh
- Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan
| | - Pei-Yi Chu
- Department of Pathology, Show Chwan Memorial Hospital, Changhua, Taiwan.,School of Medicine, Fu Jen Catholic University, New Taipei City, Taiwan
| | - Wen-Chun Tsai
- Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Chun-Teng Huang
- School of Medicine, National Yang-Ming University, Taipei, Taiwan.,Division of Haematology and Oncology, Department of Medicine, Yang-Ming Branch of Taipei City Hospital, Taipei, Taiwan
| | - Yuan-Bin Yu
- School of Medicine, National Yang-Ming University, Taipei, Taiwan.,Division of Haematology and Oncology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Tzu-Ting Huang
- Comprehensive Breast Health Centre, Taipei Veterans General Hospital, Taipei, Taiwan.,Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Po-Shen Ko
- Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan.,School of Medicine, National Yang-Ming University, Taipei, Taiwan.,Division of Haematology and Oncology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Man-Hsin Hung
- Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan.,School of Medicine, National Yang-Ming University, Taipei, Taiwan.,Division of Haematology and Oncology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Wan-Lun Wang
- Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Chung-Wai Shiau
- Institute of Biopharmaceutical Sciences, National Yang-Ming University, Taipei, Taiwan
| | - Kuen-Feng Chen
- Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan.,National Center of Excellence for Clinical Trial and Research, National Taiwan University Hospital, Taipei, Taiwan
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Zhu G, Briz V, Seinfeld J, Liu Y, Bi X, Baudry M. Calpain-1 deletion impairs mGluR-dependent LTD and fear memory extinction. Sci Rep 2017; 7:42788. [PMID: 28202907 PMCID: PMC5311935 DOI: 10.1038/srep42788] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 01/17/2017] [Indexed: 01/02/2023] Open
Abstract
Recent studies indicate that calpain-1 is required for the induction of long-term potentiation (LTP) elicited by theta-burst stimulation in field CA1 of hippocampus. Here we determined the contribution of calpain-1 in another type of synaptic plasticity, the long-term depression (LTD) elicited by activation of type-I metabotropic glutamate receptors (mGluR-LTD). mGluR-LTD was associated with calpain-1 activation following T-type calcium channel opening, and resulted in the truncation of a regulatory subunit of PP2A, B56α. This signaling pathway was required for both the early and late phase of Arc translation during mGluR-LTD, through a mechanism involving mTOR and ribosomal protein S6 activation. In contrast, in hippocampal slices from calpain-1 knock-out (KO) mice, application of the mGluR agonist, DHPG, did not result in B56α truncation, increased Arc synthesis and reduced levels of membrane GluA1-containing AMPA receptors. Consistently, mGluR-LTD was impaired in calpain-1 KO mice, and the impairment could be rescued by phosphatase inhibitors, which also restored Arc translation in response to DHPG. Furthermore, calpain-1 KO mice exhibited impairment in fear memory extinction to tone presentation. These results indicate that calpain-1 plays a critical role in mGluR-LTD and is involved in many forms of synaptic plasticity and learning and memory.
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Affiliation(s)
- Guoqi Zhu
- Graduate College of Biomedical Sciences, Pomona, CA 91766, USA
- Key Laboratory of Xin’an Medicine, Ministry of Education, Anhui University of Chinese Medicine, Hefei 230038, China
| | - Victor Briz
- Graduate College of Biomedical Sciences, Pomona, CA 91766, USA
- VIB Center for the Biology of Disease, KU Leuven, 3000 Leuven, Belgium
| | - Jeff Seinfeld
- Graduate College of Biomedical Sciences, Pomona, CA 91766, USA
| | - Yan Liu
- Graduate College of Biomedical Sciences, Pomona, CA 91766, USA
- College of Osteopathic Medicine of the Pacific Western University of Health Sciences Pomona, CA 91766, CA 91766, USA
| | - Xiaoning Bi
- College of Osteopathic Medicine of the Pacific Western University of Health Sciences Pomona, CA 91766, CA 91766, USA
| | - Michel Baudry
- Graduate College of Biomedical Sciences, Pomona, CA 91766, USA
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LncRNA AK023948 is a positive regulator of AKT. Nat Commun 2017; 8:14422. [PMID: 28176758 PMCID: PMC5309785 DOI: 10.1038/ncomms14422] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 12/28/2016] [Indexed: 12/12/2022] Open
Abstract
Despite the overwhelming number of human long non-coding RNAs (lncRNAs) reported so far, little is known about their physiological functions for the majority of them. The present study uses a CRISPR/Cas9-based synergistic activation mediator (SAM) system to identify potential lncRNAs capable of regulating AKT activity. Among lncRNAs identified from this screen, we demonstrate that AK023948 is a positive regulator for AKT. Knockout of AK023948 suppresses, whereas rescue with AK023948 restores the AKT activity. Mechanistically, AK023948 functionally interacts with DHX9 and p85. Importantly, AK023948 is required for the interaction between DHX9 and p85 to hence the p85 stability and promote AKT activity. Finally, AK023948 is upregulated in breast cancer; interrogation of TCGA data set indicates that upregulation of DHX9 in breast cancer is associated with poor survival. Together, this study demonstrates two previously uncharacterized factors AK023948 and DHX9 as important players in the AKT pathway, and that their upregulation may contribute to breast tumour progression. The function of many human long non-coding RNAs (lncRNAs) is still undetermined. Here, the authors setup a gain of function CRISPR-based screen and identify a lncRNA that positively regulates AKT activity by interacting with the RNA helicase DHX9 resulting in stabilization of PI3K regulatory subunit p85.
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Kawabata N, Matsuda M. Cell Density-Dependent Increase in Tyrosine-Monophosphorylated ERK2 in MDCK Cells Expressing Active Ras or Raf. PLoS One 2016; 11:e0167940. [PMID: 27936234 PMCID: PMC5148048 DOI: 10.1371/journal.pone.0167940] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 11/22/2016] [Indexed: 12/25/2022] Open
Abstract
The extracellular signal-regulated kinase (ERK) is one of the principal hub proteins that transmit growth signals from upstream oncogene products including Ras and BRaf to downstream effector proteins. However, there are both reports supporting and refuting the increase in ERK activity in cancer tissues expressing the active Ras and BRaf proteins. We considered that the cell density might account for this discrepancy. To examine this possibility, we prepared Madin-Darby canine kidney (MDCK) cells that expressed an active HRas, NRas, KRas, or BRaf and an ERK biosensor based on the principle of Förster resonance energy transfer (FRET). As we anticipated, expression of the active Ras or BRaf increased ERK activity at low cell densities. However, the ERK activity was markedly suppressed at high cell densities irrespective of the expression of the active Ras or BRaf. Western blotting analysis with Phos-tag gel revealed the decrease of tyrosine and threonine-diphosphorylated active ERK and the increase of tyrosine-monophosphorylated inactive ERK at high cell density. In addition, we found that calyculin A, an inhibitor for PPP-subfamily protein serine/threonine phosphatases, decreased the tyrosine-monophosphorylated ERK. Our study suggests that PPP-subfamily phosphatases may be responsible for cell density-dependent ERK dephosphorylation in cancer cells expressing active Ras or BRaf protein.
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Affiliation(s)
- Noriyuki Kawabata
- Department of Pathology and Biology of Diseases, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Michiyuki Matsuda
- Department of Pathology and Biology of Diseases, Graduate School of Medicine, Kyoto University, Kyoto, Japan
- * E-mail:
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40
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Beier A, Teichert I, Krisp C, Wolters DA, Kück U. Catalytic Subunit 1 of Protein Phosphatase 2A Is a Subunit of the STRIPAK Complex and Governs Fungal Sexual Development. mBio 2016; 7:e00870-16. [PMID: 27329756 PMCID: PMC4916389 DOI: 10.1128/mbio.00870-16] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 05/19/2016] [Indexed: 12/21/2022] Open
Abstract
UNLABELLED The generation of complex three-dimensional structures is a key developmental step for most eukaryotic organisms. The details of the molecular machinery controlling this step remain to be determined. An excellent model system to study this general process is the generation of three-dimensional fruiting bodies in filamentous fungi like Sordaria macrospora Fruiting body development is controlled by subunits of the highly conserved striatin-interacting phosphatase and kinase (STRIPAK) complex, which has been described in organisms ranging from yeasts to humans. The highly conserved heterotrimeric protein phosphatase PP2A is a subunit of STRIPAK. Here, catalytic subunit 1 of PP2A was functionally characterized. The Δpp2Ac1 strain is sterile, unable to undergo hyphal fusion, and devoid of ascogonial septation. Further, PP2Ac1, together with STRIPAK subunit PRO22, governs vegetative and stress-related growth. We revealed in vitro catalytic activity of wild-type PP2Ac1, and our in vivo analysis showed that inactive PP2Ac1 blocks the complementation of the sterile deletion strain. Tandem affinity purification, followed by mass spectrometry and yeast two-hybrid analysis, verified that PP2Ac1 is a subunit of STRIPAK. Further, these data indicate links between the STRIPAK complex and other developmental signaling pathways, implying the presence of a large interconnected signaling network that controls eukaryotic developmental processes. The insights gained in our study can be transferred to higher eukaryotes and will be important for understanding eukaryotic cellular development in general. IMPORTANCE The striatin-interacting phosphatase and kinase (STRIPAK) complex is highly conserved from yeasts to humans and is an important regulator of numerous eukaryotic developmental processes, such as cellular signaling and cell development. Although functional insights into the STRIPAK complex are accumulating, the detailed molecular mechanisms of single subunits are only partially understood. The first fungal STRIPAK was described in Sordaria macrospora, which is a well-established model organism used to study the formation of fungal fruiting bodies, three-dimensional organ-like structures. We analyzed STRIPAK subunit PP2Ac1, catalytic subunit 1 of protein phosphatase PP2A, to study the importance of the catalytic activity of this protein during sexual development. The results of our yeast two-hybrid analysis and tandem affinity purification, followed by mass spectrometry, indicate that PP2Ac1 activity connects STRIPAK with other signaling pathways and thus forms a large interconnected signaling network.
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Affiliation(s)
- Anna Beier
- Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-Universität, Bochum, Germany
| | - Ines Teichert
- Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-Universität, Bochum, Germany
| | - Christoph Krisp
- Lehrstuhl für Analytische Chemie, Ruhr-Universität, Bochum, Germany
| | - Dirk A Wolters
- Lehrstuhl für Analytische Chemie, Ruhr-Universität, Bochum, Germany
| | - Ulrich Kück
- Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-Universität, Bochum, Germany
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Activation of CK1ɛ by PP2A/PR61ɛ is required for the initiation of Wnt signaling. Oncogene 2016; 36:429-438. [PMID: 27321178 DOI: 10.1038/onc.2016.209] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 03/18/2016] [Accepted: 05/08/2016] [Indexed: 12/21/2022]
Abstract
Canonical Wnt signaling induces the stabilization of β-catenin, its translocation to the nucleus and the activation of target promoters. This pathway is initiated by the binding of Wnt ligands to the Frizzled receptor, the association of the LRP5/6 co-receptor and the formation of a complex comprising Dvl-2, Axin and protein kinases CK1α, ɛ, γ and GSK3. Among these, activation of CK1ɛ, constitutively bound to LRP5/6 through p120-catenin, is required for the association of the rest of the components. We describe here that CK1ɛ is activated by the PP2A/PR61ɛ phosphatase. Binding of Wnt ligands promotes the interaction of LRP5/6-associated CK1ɛ with Frizzled-bound PR61ɛ regulatory subunit, facilitating the access of PP2A catalytic subunit to CK1ɛ and its activation, what enables the recruitment of Dvl-2 to the receptor complex and the initiation of the Wnt pathway. Our results uncover the mechanism of activation of the canonical Wnt pathway by its ligands.
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An AXIN2 Mutant Allele Associated With Predisposition to Colorectal Neoplasia Has Context-Dependent Effects on AXIN2 Protein Function. Neoplasia 2016; 17:463-72. [PMID: 26025668 PMCID: PMC4468370 DOI: 10.1016/j.neo.2015.04.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 04/29/2015] [Indexed: 01/21/2023] Open
Abstract
Heterozygous, germline nonsense mutations in AXIN2 have been reported in two families with oligodontia and colorectal cancer (CRC) predisposition, including an AXIN2 1989G>A mutation. Somatic AXIN2 mutations predicted to generate truncated AXIN2 (trAXIN2) proteins have been reported in some CRCs. Our studies of cells from an AXIN2 1989G>A mutation carrier showed that the mutant transcripts are not significantly susceptible to nonsense-mediated decay and, thus, could encode a trAXIN2 protein. In transient transfection assays, trAXIN2 was more abundant than wild-type AXIN2 protein, and in contrast to AXIN2, glycogen synthase kinase 3β inhibition did not increase trAXIN2 levels. Like AXIN2, the trAXIN2 protein interacts with β-catenin destruction complex proteins. When ectopically overexpressed, trAXIN2 inhibits β-catenin/T-cell factor-dependent reporter gene activity and SW480 CRC cell colony formation. These findings suggest the trAXIN2 protein may retain some wild-type functions when highly expressed. However, when stably expressed in rat intestinal IEC-6 cells, the trAXIN2 protein did not match AXIN2's activity in inhibiting Wnt-mediated induction of Wnt-regulated target genes, and SW480 cells with stable expression of trAXIN2 but not AXIN2 could be generated. Our data suggest the AXIN2 1989G>A mutation may not have solely a loss-of-function role in CRC. Rather, its contribution may depend on context, with potential loss-of-function when AXIN2 levels are low, such as in the absence of Wnt pathway activation. However, given its apparent increased stability in some settings, the trAXIN2 protein might have gain-of-function in cells with substantially elevated AXIN2 expression, such as Wnt pathway-defective CRC cells.
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Theurey P, Tubbs E, Vial G, Jacquemetton J, Bendridi N, Chauvin MA, Alam MR, Le Romancer M, Vidal H, Rieusset J. Mitochondria-associated endoplasmic reticulum membranes allow adaptation of mitochondrial metabolism to glucose availability in the liver. J Mol Cell Biol 2016; 8:129-43. [DOI: 10.1093/jmcb/mjw004] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 11/01/2015] [Indexed: 12/20/2022] Open
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44
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Liao Y, Gu F, Mao X, Niu Q, Wang H, Sun Y, Song C, Qiu X, Tan L, Ding C. Regulation of de novo translation of host cells by manipulation of PERK/PKR and GADD34-PP1 activity during Newcastle disease virus infection. J Gen Virol 2016; 97:867-879. [PMID: 26869028 DOI: 10.1099/jgv.0.000426] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Viral infections result in cellular stress responses, which can trigger protein translation shutoff via phosphorylation of eukaryotic initiation factor 2 alpha (eIF2α). Newcastle disease virus (NDV) causes severe disease in poultry and selectively kills human tumour cells. In this report, we determined that infection of HeLa human cervical cancer cells and DF-1 chicken fibroblast cells with NDV maintained protein at early infection times, 0-12 h post-infection (p.i.), and gradually inhibited global protein translation at late infection times, 12-24 h p.i. Mechanistic studies showed that translation inhibition at late infection times was accompanied by phosphorylation of eIF2α, a checkpoint of translation initiation. Meanwhile, the eIF2α kinase, PKR, was upregulated and activated by phosphorylation and another eIF2α kinase, PERK, was phosphorylated and cleaved into two fragments. Pharmacological inhibition experiments revealed that only PKR activity was required for eIF2α phosphorylation, suggesting that recognition of viral dsRNA by PKR was responsible for translation shutoff. High levels of phospho-eIF2α led to preferential translation of the transcription factor ATF4 and an increase in GADD34 expression. Functionally, GADD34, in conjunction with PP1, dephosphorylated eIF2a and restored protein translation, benefiting virus protein synthesis. However, PP1 was degraded at late infection times, functionally counteracting the upregulation of GADD34. Taken together, our data support that NDV-induced translation shutoff at late infection times was attributed to sustaining phosphorylation of eIF2α, which is mediated by continual activation of PKR and degradation of PP1.
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Affiliation(s)
- Ying Liao
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Ziyue Road 518, Shanghai 200241, PRChina
| | - Feng Gu
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Ziyue Road 518, Shanghai 200241, PRChina
| | - Xiang Mao
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Ziyue Road 518, Shanghai 200241, PRChina
| | - Qiaona Niu
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Ziyue Road 518, Shanghai 200241, PRChina
| | - Huaxia Wang
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Ziyue Road 518, Shanghai 200241, PRChina
| | - Yingjie Sun
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Ziyue Road 518, Shanghai 200241, PRChina
| | - Cuiping Song
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Ziyue Road 518, Shanghai 200241, PRChina
| | - Xusheng Qiu
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Ziyue Road 518, Shanghai 200241, PRChina
| | - Lei Tan
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Ziyue Road 518, Shanghai 200241, PRChina
| | - Chan Ding
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, JiangSu 225009, PRChina.,Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Ziyue Road 518, Shanghai 200241, PRChina
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Acetylation of Aurora B by TIP60 ensures accurate chromosomal segregation. Nat Chem Biol 2016; 12:226-32. [PMID: 26829474 PMCID: PMC4798883 DOI: 10.1038/nchembio.2017] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 12/11/2015] [Indexed: 01/19/2023]
Abstract
Faithful segregation of chromosomes in mammalian cells requires bi-orientation of sister chromatids, which relies on the sensing of correct attachments between spindle microtubules and kinetochores. Although the mechanisms underlying cyclin-dependent kinase 1 (CDK1) activation, which triggers mitotic entry, have been extensively studied, the regulatory mechanisms that couple CDK1-cyclin B activity to chromosome stability are not well understood. Here, we identified a signaling axis in which Aurora B activity is modulated by CDK1-cyclin B via the acetyltransferase TIP60 in human cell division. CDK1-cyclin B phosphorylates Ser90 of TIP60, which elicits TIP60-dependent acetylation of Aurora B and promotes accurate chromosome segregation in mitosis. Mechanistically, TIP60 acetylation of Aurora B at Lys215 protects Aurora B's activation loop from dephosphorylation by the phosphatase PP2A to ensure a robust, error-free metaphase-anaphase transition. These findings delineate a conserved signaling cascade that integrates protein phosphorylation and acetylation with cell cycle progression for maintenance of genomic stability.
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Zhang Y, Jiang X, Qin C, Cuevas S, Jose PA, Armando I. Dopamine D2 receptors' effects on renal inflammation are mediated by regulation of PP2A function. Am J Physiol Renal Physiol 2016; 310:F128-34. [PMID: 26290374 PMCID: PMC4719046 DOI: 10.1152/ajprenal.00453.2014] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 06/15/2015] [Indexed: 01/11/2023] Open
Abstract
Lack or downregulation of the dopamine D2 receptor (D2R) results in increased renal expression of injury markers and proinflammatory factors that is independent of a blood pressure increase. This study aimed to determine the mechanisms involved in the regulation of renal inflammation by D2Rs. Silencing D2Rs in mouse renal proximal tubule cells increased the expression of the proinflammatory TNF-α, monocyte chemoattractant protein-1 (MCP-1), and IL-6. D2R downregulation also increased Akt phosphorylation and activity, and glycogen synthase kinase-3β (GSK3β) phosphorylation and cyclin D1 expression, downstream targets of Akt; however. phosphatidylinositol 3-kinase (PI3K) activity was not affected. Conversely, D2R stimulation decreased Akt and GSK3β phosphorylation and cyclin D1 expression. Increased phospho-Akt, in the absence of increased PI3K activity, may result from decreased Akt dephosphorylation. Inhibition of protein phosphatase 2A (PP2A) with okadaic acid reproduced the effects of D2R downregulation on Akt, GSK3β, and cyclin D1. The PP2A catalytic subunit and regulatory subunit PPP2R2C coimmunoprecipitated with the D2R. Basal phosphatase activity and the expression of PPP2R2C were decreased by D2R silencing that also blunted the increase in phosphatase activity induced by D2R stimulation. Similarly, silencing PPP2R2C also increased the phosphorylation of Akt and GSK3β. Moreover, downregulation of PPP2R2C resulted in increased expression of TNF-α, MCP-1, and IL-6, indicating that decreased phosphatase activity may be responsible for the D2R effect on inflammatory factors. Indeed, the increase in NF-κB reporter activity induced by D2R silencing was blunted by increasing PP2A activity with protamine. Our results show that D2R controls renal inflammation, at least in part, by modulation of the Akt pathway through effects on PP2A activity/expression.
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Affiliation(s)
- Yanrong Zhang
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland; Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences (CAMS) and Comparative Medicine Centre, Peking Union Medical Collage (PUMC), Beijing, P. R. China; and
| | - Xiaoliang Jiang
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland; Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences (CAMS) and Comparative Medicine Centre, Peking Union Medical Collage (PUMC), Beijing, P. R. China; and
| | - Chuan Qin
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland; Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences (CAMS) and Comparative Medicine Centre, Peking Union Medical Collage (PUMC), Beijing, P. R. China; and
| | - Santiago Cuevas
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Pedro A Jose
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland; Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Ines Armando
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
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Plácido AI, Pereira CMF, Correira SC, Carvalho C, Oliveira CR, Moreira PI. Phosphatase 2A Inhibition Affects Endoplasmic Reticulum and Mitochondria Homeostasis Via Cytoskeletal Alterations in Brain Endothelial Cells. Mol Neurobiol 2016; 54:154-168. [DOI: 10.1007/s12035-015-9640-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 12/15/2015] [Indexed: 12/30/2022]
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Barrows D, Schoenfeld SM, Hodakoski C, Silkov A, Honig B, Couvillon A, Shymanets A, Nürnberg B, Asara JM, Parsons R. p21-activated Kinases (PAKs) Mediate the Phosphorylation of PREX2 Protein to Initiate Feedback Inhibition of Rac1 GTPase. J Biol Chem 2015; 290:28915-31. [PMID: 26438819 DOI: 10.1074/jbc.m115.668244] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Indexed: 11/06/2022] Open
Abstract
Phosphatidylinositol 3,4,5-trisphosphate (PIP3)-dependent Rac exchanger 2 (PREX2) is a guanine nucleotide exchange factor (GEF) for the Ras-related C3 botulinum toxin substrate 1 (Rac1) GTPase, facilitating the exchange of GDP for GTP on Rac1. GTP-bound Rac1 then activates its downstream effectors, including p21-activated kinases (PAKs). PREX2 and Rac1 are frequently mutated in cancer and have key roles within the insulin-signaling pathway. Rac1 can be inactivated by multiple mechanisms; however, negative regulation by insulin is not well understood. Here, we show that in response to being activated after insulin stimulation, Rac1 initiates its own inactivation by decreasing PREX2 GEF activity. Following PREX2-mediated activation of Rac1 by the second messengers PIP3 or Gβγ, we found that PREX2 was phosphorylated through a PAK-dependent mechanism. PAK-mediated phosphorylation of PREX2 reduced GEF activity toward Rac1 by inhibiting PREX2 binding to PIP3 and Gβγ. Cell fractionation experiments also revealed that phosphorylation prevented PREX2 from localizing to the cellular membrane. Furthermore, the onset of insulin-induced phosphorylation of PREX2 was delayed compared with AKT. Altogether, we propose that second messengers activate the Rac1 signal, which sets in motion a cascade whereby PAKs phosphorylate and negatively regulate PREX2 to decrease Rac1 activation. This type of regulation would allow for transient activation of the PREX2-Rac1 signal and may be relevant in multiple physiological processes, including diseases such as diabetes and cancer when insulin signaling is chronically activated.
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Affiliation(s)
- Douglas Barrows
- From the Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029, the Department of Pharmacology, Columbia University, New York, New York 10032
| | - Sarah M Schoenfeld
- From the Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - Cindy Hodakoski
- From the Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - Antonina Silkov
- the Department of Biochemistry and Molecular Biophysics, Howard Hughes Medical Institute, Columbia University, New York, New York 10032
| | - Barry Honig
- the Department of Biochemistry and Molecular Biophysics, Howard Hughes Medical Institute, Columbia University, New York, New York 10032
| | | | - Aliaksei Shymanets
- the Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Pharmaceutical Research, University of Tübingen, 72074 Tübingen, Germany
| | - Bernd Nürnberg
- the Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, and Interfaculty Center of Pharmacogenomics and Pharmaceutical Research, University of Tübingen, 72074 Tübingen, Germany
| | - John M Asara
- the Division of Signal Transduction, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02115, and the Department of Medicine, Harvard Medical School, Boston, Massachusetts 02115
| | - Ramon Parsons
- From the Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029,
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Mahato P, Pandey S, Bhattacharyya S. Differential effects of protein phosphatases in the recycling of metabotropic glutamate receptor 5. Neuroscience 2015; 306:138-50. [DOI: 10.1016/j.neuroscience.2015.08.031] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 07/28/2015] [Accepted: 08/14/2015] [Indexed: 10/23/2022]
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50
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Environmental enrichment improves learning and memory and long-term potentiation in young adult rats through a mechanism requiring mGluR5 signaling and sustained activation of p70s6k. Neurobiol Learn Mem 2015; 125:126-34. [PMID: 26341144 DOI: 10.1016/j.nlm.2015.08.006] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 07/28/2015] [Accepted: 08/11/2015] [Indexed: 11/22/2022]
Abstract
Previous studies from our lab have demonstrated that mild cognitive impairments identified early in life are predictive of cognitive deficits that develop with age, suggesting that enhancements in cognition at an early age can provide a buffer against age-related cognitive decline. Environmental enrichment has been shown to improve learning and memory in the rodent, but the impact of enrichment on synaptic plasticity and the molecular mechanisms behind enrichment are not completely understood. To address these unresolved issues, we have housed 2-month old rats in environmentally enriched (EE), socially enriched (SE), or standard housing (SC) and conducted tests of learning and memory formation at various time intervals. Here we demonstrate that animals that have been exposed to one month of social or environmental enrichment demonstrate enhanced learning and memory relative to standard housed controls. However, we have found that after 4months EE animals perform better than both SE and SC groups and demonstrate an enhanced hippocampal LTP. Our results demonstrate that this LTP is dependent on mGluR5 signaling, activation of ERK and mTOR signaling cascades, and sustained phosphorylation of p70s6 kinase, thus providing a potential target mechanism for future studies of cognitive enhancement in the rodent.
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