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Jonkhout MCM, Vanhessche T, Ferreira M, Verbinnen I, Withof F, Van der Hoeven G, Szekér K, Azhir Z, Lien WH, Van Eynde A, Bollen M. Embryonic NIPP1 Depletion in Keratinocytes Triggers a Cell Cycle Arrest and Premature Senescence in Adult Mice. J Invest Dermatol 2024:S0022-202X(24)00167-2. [PMID: 38431220 DOI: 10.1016/j.jid.2024.02.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 01/24/2024] [Accepted: 02/09/2024] [Indexed: 03/05/2024]
Abstract
NIPP1 is a ubiquitously expressed regulatory subunit of PP1. Its embryonic deletion in keratinocytes causes chronic sterile skin inflammation, epidermal hyperproliferation, and resistance to mutagens in adult mice. To explore the primary effects of NIPP1 deletion, we first examined hair cycle progression of NIPP1 skin knockouts (SKOs). The entry of the first hair cycle in the SKOs was delayed owing to prolonged quiescence of hair follicle stem cells. In contrast, the entry of the second hair cycle in the SKOs was advanced as a result of precocious activation of hair follicle stem cells. The epidermis of SKOs progressively accumulated senescent cells, and this cell-fate switch was accelerated by DNA damage. Primary keratinocytes from SKO neonates and human NIPP1-depleted HaCaT keratinocytes failed to proliferate and showed an increase in the expression of cell cycle inhibitors (p21, p16/Ink4a, and/or p19/Arf) and senescence-associated-secretory-phenotype factors as well as in DNA damage (γH2AX and 53BP1). Our data demonstrate that the primary effect of NIPP1 deletion in keratinocytes is a cell cycle arrest and premature senescence that gradually progresse to chronic senescence and likely contribute to the decreased sensitivity of SKOs to mutagens.
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Affiliation(s)
- Marloes C M Jonkhout
- Laboratory of Biosignaling & Therapeutics, Department of Cellular and Molecular Medicine, University of Leuven, Leuven, Belgium
| | - Tijs Vanhessche
- Laboratory of Biosignaling & Therapeutics, Department of Cellular and Molecular Medicine, University of Leuven, Leuven, Belgium
| | - Mónica Ferreira
- Laboratory of Biosignaling & Therapeutics, Department of Cellular and Molecular Medicine, University of Leuven, Leuven, Belgium
| | - Iris Verbinnen
- Laboratory of Biosignaling & Therapeutics, Department of Cellular and Molecular Medicine, University of Leuven, Leuven, Belgium
| | - Fabienne Withof
- Laboratory of Biosignaling & Therapeutics, Department of Cellular and Molecular Medicine, University of Leuven, Leuven, Belgium
| | - Gerd Van der Hoeven
- Laboratory of Biosignaling & Therapeutics, Department of Cellular and Molecular Medicine, University of Leuven, Leuven, Belgium
| | - Kathelijne Szekér
- Laboratory of Biosignaling & Therapeutics, Department of Cellular and Molecular Medicine, University of Leuven, Leuven, Belgium
| | - Zahra Azhir
- Laboratory of Biosignaling & Therapeutics, Department of Cellular and Molecular Medicine, University of Leuven, Leuven, Belgium
| | - Wen-Hui Lien
- de Duve Institute, Faculty of Medicine, Université catholique de Louvain, Brussels, Belgium
| | - Aleyde Van Eynde
- Laboratory of Biosignaling & Therapeutics, Department of Cellular and Molecular Medicine, University of Leuven, Leuven, Belgium.
| | - Mathieu Bollen
- Laboratory of Biosignaling & Therapeutics, Department of Cellular and Molecular Medicine, University of Leuven, Leuven, Belgium
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Wu D, Van der Hoeven G, Claes Z, Van Eynde A, Bollen M. DNA damage-induced allosteric activation of protein phosphatase PP1:NIPP1 through Src kinase-induced circularization of NIPP1. FEBS J 2024. [PMID: 38303113 DOI: 10.1111/febs.17064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 12/06/2023] [Accepted: 12/28/2023] [Indexed: 02/03/2024]
Abstract
Protein phosphatase-1 (PP1) complexed to nuclear inhibitor of PP1 (NIPP1) limits DNA repair through dephosphorylation of NIPP1-recruited substrates. However, the PP1:NIPP1 holoenzyme is completely inactive under basal conditions, hinting at a DNA damage-regulated activation mechanism. Here, we report that DNA damage caused the activation of PP1:NIPP1 after a time delay of several hours through phosphorylation of NIPP1 at the C-terminal tyrosine 335 (Y335) by a Src-family kinase. PP1:NIPP1 activation partially resulted from the dissociation of the C terminus of NIPP1 from the active site of PP1. In addition, the released Y335-phosphorylated C terminus interacted with the N terminus of NIPP1 to enhance substrate recruitment by the flanking forkhead-associated (FHA) domain. Constitutive activation of PP1:NIPP1 by knock-in of a phospho-mimicking (Y335E) NIPP1 mutant led to the hypo-phosphorylation of FHA ligands and an accumulation of DNA double-strand breaks. Our data indicate that PP1:NIPP1 activation through circularization of NIPP1 is a late response to DNA damage that contributes to the timely recovery from damage repair.
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Affiliation(s)
- Dan Wu
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, Belgium
| | - Gerd Van der Hoeven
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, Belgium
| | - Zander Claes
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, Belgium
| | - Aleyde Van Eynde
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, Belgium
| | - Mathieu Bollen
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, Belgium
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3
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Corda PO, Bollen M, Ribeiro D, Fardilha M. Emerging roles of the Protein Phosphatase 1 (PP1) in the context of viral infections. Cell Commun Signal 2024; 22:65. [PMID: 38267954 PMCID: PMC10807198 DOI: 10.1186/s12964-023-01468-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 12/30/2023] [Indexed: 01/26/2024] Open
Abstract
Protein Phosphatase 1 (PP1) is a major serine/threonine phosphatase in eukaryotes, participating in several cellular processes and metabolic pathways. Due to their low substrate specificity, PP1's catalytic subunits do not exist as free entities but instead bind to Regulatory Interactors of Protein Phosphatase One (RIPPO), which regulate PP1's substrate specificity and subcellular localization. Most RIPPOs bind to PP1 through combinations of short linear motifs (4-12 residues), forming highly specific PP1 holoenzymes. These PP1-binding motifs may, hence, represent attractive targets for the development of specific drugs that interfere with a subset of PP1 holoenzymes. Several viruses exploit the host cell protein (de)phosphorylation machinery to ensure efficient virus particle formation and propagation. While the role of many host cell kinases in viral life cycles has been extensively studied, the targeting of phosphatases by viral proteins has been studied in less detail. Here, we compile and review what is known concerning the role of PP1 in the context of viral infections and discuss how it may constitute a putative host-based target for the development of novel antiviral strategies.
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Affiliation(s)
- Pedro O Corda
- Institute of Biomedicine (iBiMED), Department of Medical Sciences, University of Aveiro, Aveiro, Portugal
| | - Mathieu Bollen
- Department of Cellular and Molecular Medicine, Laboratory of Biosignaling & Therapeutics, Katholieke Universiteit Leuven, Louvain, Belgium
| | - Daniela Ribeiro
- Institute of Biomedicine (iBiMED), Department of Medical Sciences, University of Aveiro, Aveiro, Portugal.
| | - Margarida Fardilha
- Institute of Biomedicine (iBiMED), Department of Medical Sciences, University of Aveiro, Aveiro, Portugal.
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4
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Claes Z, Bollen M. A split-luciferase lysate-based approach to identify small-molecule modulators of phosphatase subunit interactions. Cell Chem Biol 2023; 30:1666-1679.e6. [PMID: 37625414 DOI: 10.1016/j.chembiol.2023.07.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 05/31/2023] [Accepted: 07/30/2023] [Indexed: 08/27/2023]
Abstract
An emerging strategy for the therapeutic targeting of protein phosphatases involves the use of compounds that interfere with the binding of regulatory subunits or substrates. However, high-throughput screening strategies for such interfering molecules are scarce. Here, we report on the conversion of the NanoBiT split-luciferase system into a robust assay for the quantification of phosphatase subunit and substrate interactions in cell lysates. The assay is suitable to screen small-molecule libraries for interfering compounds. We designed and validated split-luciferase sensors for a broad range of PP1 and PP2A holoenzymes, including sensors that selectively report on weak interaction sites. To facilitate efficient hit triaging in large-scale screening campaigns, deselection procedures were developed to eliminate assay-interfering molecules with high fidelity. As a proof-of-principle, we successfully applied the split-luciferase screening tool to identify small-molecule disruptors of the interaction between the C-terminus of PP1β and the ankyrin-repeat domain of the myosin-phosphatase targeting subunit MYPT1.
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Affiliation(s)
- Zander Claes
- Laboratory of Biosignaling and Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, 3000 Leuven, Belgium
| | - Mathieu Bollen
- Laboratory of Biosignaling and Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, 3000 Leuven, Belgium.
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5
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McClure C, Bollen M, Buttolph L, Stack E, Langley BO, Hanes D, Wright KM, Tibbitts D, Bradley R. Safety and tolerability of Pau d' Arco ( Tabebuia avellanedae) for primary dysmenorrhea: A single-arm, open-label trial on adults ages 18-45. Adv Integr Med 2022; 9:159-166. [PMID: 36960315 PMCID: PMC10032363 DOI: 10.1016/j.aimed.2022.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Objectives To evaluate the safety and tolerability of encapsulated Tabebuia avellanedae in generally healthy women aged 18-45 with primary dysmenorrhea. Methods A single arm, open-label trial was conducted in which 1050 mg/day of encapsulated Tabebuia avellanedae (Pau d'Arco) was administered to twelve healthy women aged 18-45 for eight weeks. The primary outcome was safety and tolerability as measured by standardized adverse events scales and serial collection of laboratory markers to assess general health, prothrombin times, and the presence or absence of anemia. Secondary outcomes included pain intensity, quality of life, and pain interference measured by the Visual Analog Scale (VAS), the Patient-Reported Outcomes Measurement Information System (PROMIS) 29 survey, and the PROMIS Visual Sexual Function and Satisfaction: Interfering Factors survey, respectively. Exploratory outcomes included serum concentration of high-sensitivity C-reactive protein as a marker of systemic inflammation. Results Seventy-five percent of participants (n = 9/12) completed the study. Seventy-five percent of study participants (n = 9/12) reported an adverse event, most of which were characterized as mild, and none were determined to be a Food and Drug Administration (FDA) serious adverse event. Most laboratory markers stayed within normal limits throughout the study period with a few clinically mild abnormalities. There was a significant decrease in pain intensity compared to baseline after the first dose (p < .01), after 4 weeks of treatment (p < .01), and after 8 weeks of treatment (p < .01). Over the 8-week intervention period, pain interference, quality of life, and sexual function and satisfaction scores improved nonsignificantly and hs-CRP decreased nonsignificantly. Conclusions Tabebuia avellanedae supplementation of 1050 mg/day dose for eight weeks in generally healthy women aged 18-45 with primary dysmenorrhea was generally safe, associated with moderate tolerability, and associated with significant improvements in pain intensity scores. Future studies examining the safety and efficacy of Tabebuia avellanedae on primary dysmenorrhea are warranted.
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Affiliation(s)
- C McClure
- Helfgott Research Institute, National University of Natural Medicine, Portland, Oregon, United States
| | - M Bollen
- Helfgott Research Institute, National University of Natural Medicine, Portland, Oregon, United States
| | - L Buttolph
- Helfgott Research Institute, National University of Natural Medicine, Portland, Oregon, United States
| | - E Stack
- Helfgott Research Institute, National University of Natural Medicine, Portland, Oregon, United States
| | - B O Langley
- Helfgott Research Institute, National University of Natural Medicine, Portland, Oregon, United States
| | - D Hanes
- Helfgott Research Institute, National University of Natural Medicine, Portland, Oregon, United States
| | - K M Wright
- Oregon Health & Science University, Portland, Oregon, United States
| | - D Tibbitts
- Helfgott Research Institute, National University of Natural Medicine, Portland, Oregon, United States
| | - R Bradley
- Helfgott Research Institute, National University of Natural Medicine, Portland, Oregon, United States
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6
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Raman V, Van Dessel N, Hall CL, Wetherby VE, Whitney SA, Kolewe EL, Bloom SMK, Sharma A, Hardy JA, Bollen M, Van Eynde A, Forbes NS. Intracellular delivery of protein drugs with an autonomously lysing bacterial system reduces tumor growth and metastases. Nat Commun 2021; 12:6116. [PMID: 34675204 PMCID: PMC8531320 DOI: 10.1038/s41467-021-26367-9] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 10/01/2021] [Indexed: 12/25/2022] Open
Abstract
Critical cancer pathways often cannot be targeted because of limited efficiency crossing cell membranes. Here we report the development of a Salmonella-based intracellular delivery system to address this challenge. We engineer genetic circuits that (1) activate the regulator flhDC to drive invasion and (2) induce lysis to release proteins into tumor cells. Released protein drugs diffuse from Salmonella containing vacuoles into the cellular cytoplasm where they interact with their therapeutic targets. Control of invasion with flhDC increases delivery over 500 times. The autonomous triggering of lysis after invasion makes the platform self-limiting and prevents drug release in healthy organs. Bacterial delivery of constitutively active caspase-3 blocks the growth of hepatocellular carcinoma and lung metastases, and increases survival in mice. This success in targeted killing of cancer cells provides critical evidence that this approach will be applicable to a wide range of protein drugs for the treatment of solid tumors.
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Affiliation(s)
- Vishnu Raman
- Department of Chemical Engineering, University of Massachusetts, Amherst, Amherst, MA, USA
- Ernest Pharmaceuticals, LLC, Hadley, MA, USA
| | - Nele Van Dessel
- Department of Chemical Engineering, University of Massachusetts, Amherst, Amherst, MA, USA
- Ernest Pharmaceuticals, LLC, Hadley, MA, USA
| | - Christopher L Hall
- Department of Chemical Engineering, University of Massachusetts, Amherst, Amherst, MA, USA
- Ernest Pharmaceuticals, LLC, Hadley, MA, USA
| | | | - Samantha A Whitney
- Department of Chemical Engineering, University of Massachusetts, Amherst, Amherst, MA, USA
| | - Emily L Kolewe
- Department of Chemical Engineering, University of Massachusetts, Amherst, Amherst, MA, USA
| | - Shoshana M K Bloom
- Department of Chemical Engineering, University of Massachusetts, Amherst, Amherst, MA, USA
| | - Abhinav Sharma
- Department of Chemical Engineering, University of Massachusetts, Amherst, Amherst, MA, USA
| | - Jeanne A Hardy
- Department of Chemistry, University of Massachusetts, Amherst, Amherst, MA, USA
- Molecular and Cell Biology Program, University of Massachusetts, Amherst, Amherst, MA, USA
- Institute for Applied Life Science, University of Massachusetts, Amherst, Amherst, MA, USA
| | - Mathieu Bollen
- Laboratory of Biosignaling & Therapeutics, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Aleyde Van Eynde
- Laboratory of Biosignaling & Therapeutics, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Neil S Forbes
- Department of Chemical Engineering, University of Massachusetts, Amherst, Amherst, MA, USA.
- Ernest Pharmaceuticals, LLC, Hadley, MA, USA.
- Molecular and Cell Biology Program, University of Massachusetts, Amherst, Amherst, MA, USA.
- Institute for Applied Life Science, University of Massachusetts, Amherst, Amherst, MA, USA.
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7
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Versele M, del Pino Garcia J, Vandecaetsbeek I, Castermans K, Kellens R, Haeck W, Klaassen H, Bourin A, De Clercq D, Allasia S, Boland S, Marchand A, Chaltin P, Bollen M. Abstract 53: Discovery of novel potent and orally bioavailable small-molecule inhibitors of ENPP1 to stabilize cGAMP and ATP in the tumor microenvironment and boost anti-tumor immunity. Cancer Res 2021. [DOI: 10.1158/1538-7445.am2021-53] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Extracellular 2',3'-cyclic GMP-AMP (cGAMP) has a critical immune-transmitter role in the tumor microenvironment (TME). Tumor cells produce and secrete cGAMP, which primes immune cells for tumor rejection through STING (stimulator of interferon genes) signalling (Marcus et al., Immunity 2018; Carozza et al., Nature Cancer 2020). Ecto-nucleotide pyrophosphatase/phosphodiesterase-1 (ENPP1) is the only enzyme known to hydrolyze extracellular cGAMP. In concert with the ectoATPase CD39 and the 5'-nucleotidase CD73, ENPP1 also contributes to the generation of an immunosuppressive TME by converting extracellular ATP into adenosine. ENPP1 is overexpressed in a number of tumor types, including breast cancer, liver cancer, thyroid cancer and sarcomas, and has been associated with poor outcome. Hence, inhibition of ENPP1 is an emerging strategy to augment anti-tumor immunity by stabilizing extracellular cGAMP and ATP, thereby turning cold tumors into immunologically hot tumors. Here, we report on the identification and characterization of novel chemical series of ENPP1 inhibitors. A drug-like small-molecule library (~160,000 compounds) was screened to identify inhibitors of ENPP1-mediated cGAMP hydrolysis. Hits were confirmed to also inhibit ATP hydrolysis by ENPP1, but not nucleotide hydrolysis mediated by the closely related ENPP2 (autotaxin) enzyme. A selection of hits, chemically distinct from previously reported ENPP1 inhibitors (such as those based on QS1; Carroza et al, Cell Chem Biol, 2020), were subjected to hit-to-lead optimization supported by structure-based guidance. This led to the identification of ENPP1 inhibitors with sub-nM potency on ENPP1 in biochemical assays, which maintained a >1000x selectivity window with respect to ENPP2 and to other phosphodiesterases. These compounds translated well to stabilization of nucleotides in the presence of ENPP1-overexpressing cancer cell lines, with IC50 values in the nM range. A selection of compounds was profiled for DMPK (drug metabolism and pharmacokinetic) parameters, and compounds with a suitable profile were prioritized for in vivo evaluation. Orally bio-available, metabolically stable compounds were assessed in mouse syngeneic tumor models, selected on the basis of high ENPP1 and high cGAS (cGAMP synthase) expression. Stabilization of cGAMP, activation of a STING-mediated cytokine response and immune-cell infiltration/activation in the TME were used as pharmacodynamic endpoints. An update on in vivo efficacy data in a range of ENPP1-positive tumor models will be provided during the presentation. These novel orally bioavailable ENPP1 inhibitors unleash local, TME-restricted, innate immune activation, and hold the promise to overcome the current limitations of direct STING agonists.
Citation Format: Matthias Versele, Javier del Pino Garcia, Ilse Vandecaetsbeek, Karolien Castermans, Ranie Kellens, Wanda Haeck, Hugo Klaassen, Arnaud Bourin, Dries De Clercq, Sara Allasia, Sandro Boland, Arnaud Marchand, Patrick Chaltin, Mathieu Bollen. Discovery of novel potent and orally bioavailable small-molecule inhibitors of ENPP1 to stabilize cGAMP and ATP in the tumor microenvironment and boost anti-tumor immunity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 53.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | - Patrick Chaltin
- 3Center for Drug Design and Discovery (CD3), Leuven, Belgium
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8
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Cao X, Lemaire S, Bollen M. Protein phosphatase 1: life-course regulation by SDS22 and Inhibitor-3. FEBS J 2021; 289:3072-3085. [PMID: 34028981 DOI: 10.1111/febs.16029] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/06/2021] [Accepted: 05/20/2021] [Indexed: 12/13/2022]
Abstract
Protein phosphatase 1 (PP1) is expressed in all eukaryotic cells and catalyzes a sizable fraction of protein Ser/Thr dephosphorylation events. It is tightly regulated in space and time through association with a wide array of regulatory interactors of protein phosphatase one (RIPPOs). Suppressor-of-Dis2-number 2 (SDS22) and Inhibitor-3 (I3), which form a ternary complex with PP1, are the first two evolved and most widely expressed RIPPOs. Their deletion causes mitotic-arrest phenotypes and is lethal in some organisms. The role of SDS22 and I3 in PP1 regulation has been a mystery for decades as they were independently identified as both activators and inhibitors of PP1. This conundrum has largely been solved by recent reports showing that SDS22 and I3 control multiple steps of the life course of PP1. Indeed, they contribute to (a) the stabilization and activation of newly translated PP1, (b) the translocation of PP1 to the nucleus, and (c) the storage of PP1 as a reserve for holoenzyme assembly. Preliminary evidence suggests that SDS22 and I3 may also function as scavengers of released or aged PP1 for re-use in holoenzyme assembly or proteolytical degradation, respectively. Hence, SDS22 and I3 are emerging as master regulators of the life course of PP1.
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Affiliation(s)
- Xinyu Cao
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, Belgium
| | - Sarah Lemaire
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, Belgium
| | - Mathieu Bollen
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, Belgium
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9
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Salvi F, Hoermann B, Del Pino García J, Fontanillo M, Derua R, Beullens M, Bollen M, Barabas O, Köhn M. Towards Dissecting the Mechanism of Protein Phosphatase-1 Inhibition by Its C-Terminal Phosphorylation. Chembiochem 2020; 22:834-838. [PMID: 33085143 PMCID: PMC7984433 DOI: 10.1002/cbic.202000669] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 10/21/2020] [Indexed: 01/23/2023]
Abstract
Phosphoprotein phosphatase‐1 (PP1) is a key player in the regulation of phospho‐serine (pSer) and phospho‐threonine (pThr) dephosphorylation and is involved in a large fraction of cellular signaling pathways. Aberrant activity of PP1 has been linked to many diseases, including cancer and heart failure. Besides a well‐established activity control by regulatory proteins, an inhibitory function for phosphorylation (p) of a Thr residue in the C‐terminal intrinsically disordered tail of PP1 has been demonstrated. The associated phenotype of cell‐cycle arrest was repeatedly proposed to be due to autoinhibition of PP1 through either conformational changes or substrate competition. Here, we use PP1 variants created by mutations and protein semisynthesis to differentiate between these hypotheses. Our data support the hypothesis that pThr exerts its inhibitory function by mediating protein complex formation rather than by a direct mechanism of structural changes or substrate competition.
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Affiliation(s)
- Francesca Salvi
- Genome Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117, Heidelberg, Germany
| | - Bernhard Hoermann
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Schänzlestraße 18, 79104, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Schänzlestraße 18, 79104, Freiburg, Germany
| | - Javier Del Pino García
- Laboratory of Biosignaling and Therapeutics Department of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Miriam Fontanillo
- Genome Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117, Heidelberg, Germany
| | - Rita Derua
- Laboratory of Protein Phosphorylation and Proteomics Department of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, 3000, Leuven, Belgium.,SyBioMa, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Monique Beullens
- Laboratory of Biosignaling and Therapeutics Department of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Mathieu Bollen
- Laboratory of Biosignaling and Therapeutics Department of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Orsolya Barabas
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117, Heidelberg, Germany
| | - Maja Köhn
- Genome Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117, Heidelberg, Germany.,Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Schänzlestraße 18, 79104, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Schänzlestraße 18, 79104, Freiburg, Germany
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10
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De Munter S, Van der Hoeven G, Bollen M. RepoMan stimulates the chromosome-dependent pathway of microtubule assembly. Cell Cycle 2020; 19:3029-3041. [PMID: 33054506 PMCID: PMC7747800 DOI: 10.1080/15384101.2020.1830607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 07/28/2020] [Accepted: 08/25/2020] [Indexed: 10/23/2022] Open
Abstract
RepoMan is a chromosome-associated scaffold protein that integrates signaling of multiple kinases and phosphatases to coordinate spindle-kinetochore interactions, chromosome (de)condensation and nuclear envelope (dis)assembly during mitosis. Another key mitotic event is the assembly of a microtubule-based spindle, which involves redundant pathways emanating from the centrosomes, microtubules and chromosomes. Here we describe a novel mitotic function of RepoMan in regulating chromosome-dependent microtubule assembly. At limiting concentrations of microtubule-destabilizing agents, RepoMan-depleted cells showed enhanced chromosome clustering. This clustering was completely dependent on the partial inhibition of microtubule growth originating from the chromosome-dependent pathway. We also demonstrated that RepoMan interacts with prime regulators of the chromosome-dependent spindle assembly such as NuSAP1, NuMA, and TPX2. In addition, RepoMan was required to enable or maintain phosphorylation of NuSAP1 at CDK sites, thereby enabling activation of NuSAP1 through dissociation of inhibitory importin β/7. Our data identify RepoMan as an enhancer of microtubule assembly at chromosomes.
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Affiliation(s)
- Sofie De Munter
- Department of Cellular and Molecular Medicine, Laboratory of Biosignaling & Therapeutics, KU Leuven, Leuven, Belgium
| | - Gerd Van der Hoeven
- Department of Cellular and Molecular Medicine, Laboratory of Biosignaling & Therapeutics, KU Leuven, Leuven, Belgium
| | - Mathieu Bollen
- Department of Cellular and Molecular Medicine, Laboratory of Biosignaling & Therapeutics, KU Leuven, Leuven, Belgium
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11
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Cristofoli F, Moss T, Moore HW, Devriendt K, Flanagan-Steet H, May M, Jones J, Roelens F, Fons C, Fernandez A, Martorell L, Selicorni A, Maitz S, Vitiello G, Van der Hoeven G, Skinner SA, Bollen M, Vermeesch JR, Steet R, Van Esch H. De Novo Variants in LMNB1 Cause Pronounced Syndromic Microcephaly and Disruption of Nuclear Envelope Integrity. Am J Hum Genet 2020; 107:753-762. [PMID: 32910914 PMCID: PMC7536573 DOI: 10.1016/j.ajhg.2020.08.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 08/18/2020] [Indexed: 11/22/2022] Open
Abstract
Lamin B1 plays an important role in the nuclear envelope stability, the regulation of gene expression, and neural development. Duplication of LMNB1, or missense mutations increasing LMNB1 expression, are associated with autosomal-dominant leukodystrophy. On the basis of its role in neurogenesis, it has been postulated that LMNB1 variants could cause microcephaly. Here, we confirm this hypothesis with the identification of de novo mutations in LMNB1 in seven individuals with pronounced primary microcephaly (ranging from -3.6 to -12 SD) associated with relative short stature and variable degree of intellectual disability and neurological features as the core symptoms. Simplified gyral pattern of the cortex and abnormal corpus callosum were noted on MRI of three individuals, and these individuals also presented with a more severe phenotype. Functional analysis of the three missense mutations showed impaired formation of the LMNB1 nuclear lamina. The two variants located within the head group of LMNB1 result in a decrease in the nuclear localization of the protein and an increase in misshapen nuclei. We further demonstrate that another mutation, located in the coil region, leads to increased frequency of condensed nuclei and lower steady-state levels of lamin B1 in proband lymphoblasts. Our findings collectively indicate that de novo mutations in LMNB1 result in a dominant and damaging effect on nuclear envelope formation that correlates with microcephaly in humans. This adds LMNB1 to the growing list of genes implicated in severe autosomal-dominant microcephaly and broadens the phenotypic spectrum of the laminopathies.
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Affiliation(s)
- Francesca Cristofoli
- Center for Human Genetics, University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Tonya Moss
- JC Self Research Institute, Greenwood Genetic Center, 113 Gregor Mendel Circle, Greenwood, SC 29646, USA
| | - Hannah W Moore
- Greenwood Genetic Center, 106 Gregor Mendel Circle, Greenwood, SC 29646, USA
| | - Koen Devriendt
- Center for Human Genetics, University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Heather Flanagan-Steet
- JC Self Research Institute, Greenwood Genetic Center, 113 Gregor Mendel Circle, Greenwood, SC 29646, USA
| | - Melanie May
- JC Self Research Institute, Greenwood Genetic Center, 113 Gregor Mendel Circle, Greenwood, SC 29646, USA
| | - Julie Jones
- JC Self Research Institute, Greenwood Genetic Center, 113 Gregor Mendel Circle, Greenwood, SC 29646, USA
| | - Filip Roelens
- Pediatric Neurology, Department of Pediatrics, AZ Delta, Brugsesteenweg 90, 8800 Roeselare, Belgium
| | - Carmen Fons
- Pediatric Neurology Department, Sant Joan de Déu Hospital, Passeig de Sant Joan de Déu 2, 08950 Barcelona, Spain
| | - Anna Fernandez
- Pediatric Neurology Department, Sant Joan de Déu Hospital, Passeig de Sant Joan de Déu 2, 08950 Barcelona, Spain
| | - Loreto Martorell
- Department of Genetic and Molecular Medicine IPER, Institut de Recerca, Sant Joan de Déu Hospital, Passeig de Sant Joan de Déu 2, 08950 Barcelona, Spain
| | - Angelo Selicorni
- Pediatric Department, ASST Lariana, Sant'Anna Hospital, Via Ravona 20, 22042 Como, Italy
| | - Silvia Maitz
- Clinical Pediatric Genetics Unit, MBBM Foundation, S. Gerardo Hospital, Via Pergolesi 33, 20900 Monza, Italy
| | - Giuseppina Vitiello
- Department of Translational Medicine and Molecular Medicine and Medical Biotechnologies, Federico II University, via Pansini 5, 80131 Naples, Italy
| | - Gerd Van der Hoeven
- Laboratory of Biosignalling & Therapeutics, Department of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Steven A Skinner
- Greenwood Genetic Center, 106 Gregor Mendel Circle, Greenwood, SC 29646, USA
| | - Mathieu Bollen
- Laboratory of Biosignalling & Therapeutics, Department of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Joris R Vermeesch
- Center for Human Genetics, University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Richard Steet
- JC Self Research Institute, Greenwood Genetic Center, 113 Gregor Mendel Circle, Greenwood, SC 29646, USA.
| | - Hilde Van Esch
- Center for Human Genetics, University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium; Laboratory for the Genetics of Cognition, Department of Human Genetics, KU Leuven, Herestraat 49, 3000 Leuven, Belgium.
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12
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Manzione MG, Rombouts J, Steklov M, Pasquali L, Sablina A, Gelens L, Qian J, Bollen M. Co-regulation of the antagonistic RepoMan:Aurora-B pair in proliferating cells. Mol Biol Cell 2020; 31:419-438. [PMID: 31967936 PMCID: PMC7185888 DOI: 10.1091/mbc.e19-12-0698] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Chromosome segregation during mitosis is antagonistically regulated by the Aurora-B kinase and RepoMan (recruits PP1 onto mitotic chromatin at anaphase)-associated phosphatases PP1/PP2A. Aurora B is overexpressed in many cancers but, surprisingly, this only rarely causes lethal aneuploidy. Here we show that RepoMan abundance is regulated by the same mechanisms that control Aurora B, including FOXM1-regulated expression and proteasomal degradation following ubiquitination by APC/C-CDH1 or SCFFBXW7. The deregulation of these mechanisms can account for the balanced co-overexpression of Aurora B and RepoMan in many cancers, which limits chromosome segregation errors. In addition, Aurora B and RepoMan independently promote cancer cell proliferation by reducing checkpoint-induced cell-cycle arrest during interphase. The co–up-regulation of RepoMan and Aurora B in tumors is inversely correlated with patient survival, underscoring its potential importance for tumor progression. Finally, we demonstrate that high RepoMan levels sensitize cancer cells to Aurora-B inhibitors. Hence, the co–up-regulation of RepoMan and Aurora B is associated with tumor aggressiveness but also exposes a vulnerable target for therapeutic intervention.
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Affiliation(s)
| | - Jan Rombouts
- Laboratory of Dynamics in Biological Systems, Department of Cellular and Molecular Medicine, KU Leuven, B-3000 Leuven, Belgium
| | - Mikhail Steklov
- VIB-KU Leuven Center for Cancer Biology, VIB, 3000 Leuven, Belgium
| | - Lorenzo Pasquali
- Dermatology and Venereology Section, Department of Medicine Solna, Karolinska Institutet, SE-17176 Stockholm, Sweden
| | - Anna Sablina
- Department of Oncology, KU Leuven, B-3000 Leuven, Belgium.,VIB-KU Leuven Center for Cancer Biology, VIB, 3000 Leuven, Belgium
| | - Lendert Gelens
- Laboratory of Dynamics in Biological Systems, Department of Cellular and Molecular Medicine, KU Leuven, B-3000 Leuven, Belgium
| | - Junbin Qian
- Laboratory of Biosignaling & Therapeutics, KU Leuven, B-3000 Leuven, Belgium.,Laboratory for Translational Genetics, Department of Human Genetics, KU Leuven, B-3000 Leuven, Belgium.,VIB-KU Leuven Center for Cancer Biology, VIB, 3000 Leuven, Belgium
| | - Mathieu Bollen
- Laboratory of Biosignaling & Therapeutics, KU Leuven, B-3000 Leuven, Belgium
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13
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Claes Z, Jonkhout M, Crespillo-Casado A, Bollen M. The antibiotic robenidine exhibits guanabenz-like cytoprotective properties by a mechanism independent of protein phosphatase PP1:PPP1R15A. J Biol Chem 2019; 294:13478-13486. [PMID: 31337709 DOI: 10.1074/jbc.ra119.008857] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 07/22/2019] [Indexed: 01/11/2023] Open
Abstract
The aminoguanidine compound robenidine is widely used as an antibiotic for the control of coccidiosis, a protozoal infection in poultry and rabbits. Interestingly, robenidine is structurally similar to guanabenz (analogs), which are currently undergoing clinical trials as cytoprotective agents for the management of neurodegenerative diseases. Here we show that robenidine and guanabenz protect cells from a tunicamycin-induced unfolded protein response to a similar degree. Both compounds also reduced the tumor necrosis factor α-induced activation of NF-κB. The cytoprotective effects of guanabenz (analogs) have been explained previously by their ability to maintain eIF2α phosphorylation by allosterically inhibiting protein phosphatase PP1:PPP1R15A. However, using a novel split-luciferase-based protein-protein interaction assay, we demonstrate here that neither robenidine nor guanabenz disrupt the interaction between PPP1R15A and either PP1 or eIF2α in intact cells. Moreover, both drugs also inhibited the unfolded protein response in cells that expressed a nonphosphorylatable mutant (S51A) of eIF2α. Our results identify robenidine as a PP1:PPP1R15A-independent cytoprotective compound that holds potential for the management of protein misfolding-associated diseases.
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Affiliation(s)
- Zander Claes
- Laboratory of Biosignaling and Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, 3000 Leuven, Belgium
| | - Marloes Jonkhout
- Laboratory of Biosignaling and Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, 3000 Leuven, Belgium
| | - Ana Crespillo-Casado
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - Mathieu Bollen
- Laboratory of Biosignaling and Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, 3000 Leuven, Belgium.
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14
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Abstract
Timers and sensors are common devices that make our daily life safer, more convenient, and more efficient. In a cellular context, they arguably play an even more crucial role as they ensure the survival of cells in the presence of various extrinsic and intrinsic stresses. Biological timers and sensors generate distinct signaling profiles, enabling them to produce different types of cellular responses. Recent data suggest that they can work together to guarantee correct timing and responsiveness. By exploring examples of cellular stress signaling from mitosis, DNA damage, and hypoxia, the authors discuss the common architecture of timer-sensor integration, and how its added features contribute to the generation of desired signaling profiles when dealing with stresses of variable duration and strength. The authors propose timer-sensor integration as a widespread mechanism with profound biological implications and therapeutic potential.
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Affiliation(s)
- Junbin Qian
- Laboratory of Biosignaling & Therapeutics, Department of Cellular and Molecular Medicine, KU Leuven, 3000, Leuven, Belgium.,VIB Center for Cancer Biology, 3000, Leuven, Belgium.,Laboratory for Translational Genetics, Department of Human Genetics, KU Leuven, 3000, Leuven, Belgium
| | - Lendert Gelens
- Laboratory of Dynamics in Biological Systems, Department of Cellular and Molecular Medicine, KU Leuven, 3000, Leuven, Belgium
| | - Mathieu Bollen
- Laboratory of Biosignaling & Therapeutics, Department of Cellular and Molecular Medicine, KU Leuven, 3000, Leuven, Belgium
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15
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Ferreira M, Verbinnen I, Fardilha M, Van Eynde A, Bollen M. The deletion of the protein phosphatase 1 regulator NIPP1 in testis causes hyperphosphorylation and degradation of the histone methyltransferase EZH2. J Biol Chem 2018; 293:18031-18039. [PMID: 30305391 DOI: 10.1074/jbc.ac118.005577] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 09/25/2018] [Indexed: 12/15/2022] Open
Abstract
Germ cell proliferation is epigenetically controlled, mainly through DNA methylation and histone modifications. However, the pivotal epigenetic regulators of germ cell self-renewal and differentiation in postnatal testis are still poorly defined. The histone methyltransferase enhancer of zeste homolog 2 (EZH2) is the catalytic subunit of Polycomb repressive complex 2, represses target genes through trimethylation of histone H3 at Lys-27 (H3K27me3), and interacts (in)directly with both protein phosphatase 1 (PP1) and nuclear inhibitor of PP1 (NIPP1). Here, we report that postnatal, testis-specific ablation of NIPP1 in mice results in loss of EZH2 and reduces H3K27me3 levels. Mechanistically, the NIPP1 deletion abrogated PP1-mediated EZH2 dephosphorylation at two cyclin-dependent kinase sites (Thr-345/487), thereby generating hyperphosphorylated EZH2, which is a substrate for proteolytic degradation. Accordingly, alanine mutation of these residues prolonged the half-life of EZH2 in male germ cells. Our study discloses a key role for the PP1:NIPP1 holoenzyme in stabilizing EZH2 and maintaining the H3K27me3 mark on genes that are important for germ cell development and spermatogenesis.
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Affiliation(s)
- Mónica Ferreira
- From the Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium and; Institute for Research in Biomedicine (iBiMED), Health Sciences Department, University of Aveiro, 3810 Aveiro, Portugal
| | - Iris Verbinnen
- From the Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium and
| | - Margarida Fardilha
- Institute for Research in Biomedicine (iBiMED), Health Sciences Department, University of Aveiro, 3810 Aveiro, Portugal
| | - Aleyde Van Eynde
- From the Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium and.
| | - Mathieu Bollen
- From the Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium and.
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16
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Bajaj R, Bollen M, Peti W, Page R. KNL1 Binding to PP1 and Microtubules Is Mutually Exclusive. Structure 2018; 26:1327-1336.e4. [PMID: 30100357 PMCID: PMC6601351 DOI: 10.1016/j.str.2018.06.013] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 06/19/2018] [Accepted: 06/29/2018] [Indexed: 01/07/2023]
Abstract
The kinetochore scaffold 1 (KNL1) protein coordinates the spindle assembly checkpoint (SAC), a signaling pathway that delays chromosome segregation until all sister chromatids are properly attached to spindle microtubules. Recently, microtubules and protein phosphatase 1 (PP1), which both bind the N-terminal domain of KNL1, have emerged as regulators of the SAC; however, how these proteins interact to contribute to SAC signaling is unknown. Here, we use X-ray crystallography, nuclear magnetic resonance spectroscopy, and biochemical assays to show how KNL1 binds both PP1 and microtubules. Unexpectedly, we discovered that PP1 and microtubules bind KNL1 via overlapping binding sites. Further, we showed that Aurora B kinase phosphorylation results in distinct patterns of KNL1 complex disruption. Finally, combining this data with co-sedimentation assays unequivocally demonstrated that microtubules and PP1 binding to KNL1 is mutually exclusive, with preferential formation of the KNL1:PP1 holoenzyme in the presence of PP1.
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Affiliation(s)
- Rakhi Bajaj
- Department of Chemistry and Biochemistry, University of Arizona, AZ 85721, USA
| | - Mathieu Bollen
- Laboratory of Biosignaling & Therapeutics, Department of Cellular and Molecular Medicine, KU Leuven, Belgium
| | - Wolfgang Peti
- Department of Chemistry and Biochemistry, University of Arizona, AZ 85721, USA
| | - Rebecca Page
- Department of Chemistry and Biochemistry, University of Arizona, AZ 85721, USA;,Corresponding (lead contact) author: Rebecca Page, Department of Chemistry and Biochemistry, University of Arizona, AZ 85721, USA., 520.626.0389,
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17
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Wu D, De Wever V, Derua R, Winkler C, Beullens M, Van Eynde A, Bollen M. A substrate-trapping strategy for protein phosphatase PP1 holoenzymes using hypoactive subunit fusions. J Biol Chem 2018; 293:15152-15162. [PMID: 30115685 DOI: 10.1074/jbc.ra118.004132] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 08/13/2018] [Indexed: 01/24/2023] Open
Abstract
The protein Ser/Thr phosphatase PP1 catalyzes an important fraction of protein dephosphorylation events and forms highly specific holoenzymes through an association with regulatory interactors of protein phosphatase one (RIPPOs). The functional characterization of individual PP1 holoenzymes is hampered by the lack of straightforward strategies for substrate mapping. Because efficient substrate recruitment often involves binding to both PP1 and its associated RIPPO, here we examined whether PP1-RIPPO fusions can be used to trap substrates for further analysis. Fusions of an hypoactive point mutant of PP1 and either of four tested RIPPOs accumulated in HEK293T cells with their associated substrates and were co-immunoprecipitated for subsequent identification of the substrates by immunoblotting or MS analysis. Hypoactive fusions were also used to study RIPPOs themselves as substrates for associated PP1. In contrast, substrate trapping was barely detected with active PP1-RIPPO fusions or with nonfused PP1 or RIPPO subunits. Our results suggest that hypoactive fusions of PP1 subunits represent an easy-to-use tool for substrate identification of individual holoenzymes.
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Affiliation(s)
- Dan Wu
- From the Laboratory of Biosignaling and Therapeutics
| | | | - Rita Derua
- the Protein Phosphorylation and Proteomics Lab, KU Leuven Department of Cellular and Molecular Medicine, and.,SyBioMa, University of Leuven, 3000 Leuven, Belgium
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18
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Ferreira M, Beullens M, Bollen M, Van Eynde A. Functions and therapeutic potential of protein phosphatase 1: Insights from mouse genetics. Biochim Biophys Acta Mol Cell Res 2018; 1866:16-30. [PMID: 30056088 PMCID: PMC7114192 DOI: 10.1016/j.bbamcr.2018.07.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 07/16/2018] [Accepted: 07/19/2018] [Indexed: 02/07/2023]
Abstract
Protein phosphatase 1 (PP1) catalyzes more than half of all phosphoserine/threonine dephosphorylation reactions in mammalian cells. In vivo PP1 does not exist as a free catalytic subunit but is always associated with at least one regulatory PP1-interacting protein (PIP) to generate a large set of distinct holoenzymes. Each PP1 complex controls the dephosphorylation of only a small subset of PP1 substrates. We screened the literature for genetically engineered mouse models and identified models for all PP1 isoforms and 104 PIPs. PP1 itself and at least 49 PIPs were connected to human disease-associated phenotypes. Additionally, phenotypes related to 17 PIPs were clearly linked to altered PP1 function, while such information was lacking for 32 other PIPs. We propose structural reverse genetics, which combines structural characterization of proteins with mouse genetics, to identify new PP1-related therapeutic targets. The available mouse models confirm the pleiotropic action of PP1 in health and diseases. Four protein phosphatases 1 (PP1) isoforms and >200 PP1-interacting proteins (PIPs) Genetically engineered mice of 49 PIPs display human disease-associated phenotypes. The use of structural reverse genetics to identify the PP1-dependent phenotypes Various interaction sites in PP1:PIP complexes suit for therapeutic targeting.
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Affiliation(s)
- Mónica Ferreira
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Monique Beullens
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Mathieu Bollen
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Aleyde Van Eynde
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium.
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19
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Winkler C, Rouget R, Wu D, Beullens M, Van Eynde A, Bollen M. Overexpression of PP1-NIPP1 limits the capacity of cells to repair DNA double-strand breaks. J Cell Sci 2018; 131:jcs.214932. [PMID: 29898919 DOI: 10.1242/jcs.214932] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 05/29/2018] [Indexed: 12/20/2022] Open
Abstract
The ubiquitously expressed nuclear protein NIPP1 (also known as PPP1R8) recruits phosphoproteins for regulated dephosphorylation by the associated protein phosphatase PP1. To bypass the PP1 titration artifacts seen upon NIPP1 overexpression, we have engineered covalently linked fusions of PP1 and NIPP1, and demonstrate their potential to selectively explore the function of the PP1:NIPP1 holoenzyme. By using inducible stable cell lines, we show that PP1-NIPP1 fusions cause replication stress in a manner that requires both PP1 activity and substrate recruitment via the ForkHead Associated domain of NIPP1. More specifically, PP1-NIPP1 expression resulted in the build up of RNA-DNA hybrids (R-loops), enhanced chromatin compaction and a diminished repair of DNA double-strand breaks (DSBs), culminating in the accumulation of DSBs. These effects were associated with a reduced expression of DNA damage signaling and repair proteins. Our data disclose a key role for dephosphorylation of PP1:NIPP1 substrates in setting the threshold for DNA repair, and indicate that activators of this phosphatase hold therapeutic potential as sensitizers for DNA-damaging agents.
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Affiliation(s)
- Claudia Winkler
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Raphael Rouget
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Dan Wu
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Monique Beullens
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Aleyde Van Eynde
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Mathieu Bollen
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
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20
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Crespillo-Casado A, Claes Z, Choy MS, Peti W, Bollen M, Ron D. A Sephin1-insensitive tripartite holophosphatase dephosphorylates translation initiation factor 2α. J Biol Chem 2018; 293:7766-7776. [PMID: 29618508 PMCID: PMC5961032 DOI: 10.1074/jbc.ra118.002325] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 03/28/2018] [Indexed: 11/10/2022] Open
Abstract
The integrated stress response (ISR) is regulated by kinases that phosphorylate the α subunit of translation initiation factor 2 and phosphatases that dephosphorylate it. Genetic and biochemical observations indicate that the eIF2αP-directed holophosphatase, a therapeutic target in diseases of protein misfolding, is comprised of a regulatory subunit, PPP1R15, and a catalytic subunit, protein phosphatase 1 (PP1). In mammals, there are two isoforms of the regulatory subunit, PPP1R15A and PPP1R15B, with overlapping roles in the essential function of eIF2αP dephosphorylation. However, conflicting reports have appeared regarding the requirement for an additional co-factor, G-actin, in enabling substrate-specific dephosphorylation by PPP1R15-containing PP1 holoenzymes. An additional concern relates to the sensitivity of the holoenzyme to the [(o-chlorobenzylidene)amino]guanidines Sephin1 or guanabenz, putative small-molecule proteostasis modulators. It has been suggested that the source and method of purification of the PP1 catalytic subunit and the presence or absence of an N-terminal repeat–containing region in the PPP1R15A regulatory subunit might influence the requirement for G-actin and sensitivity of the holoenzyme to inhibitors. We found that eIF2αP dephosphorylation by PP1 was moderately stimulated by repeat-containing PPP1R15A in an unphysiological low ionic strength buffer, whereas stimulation imparted by the co-presence of PPP1R15A and G-actin was observed under a broad range of conditions, low and physiological ionic strength, regardless of whether the PPP1R15A regulatory subunit had or lacked the N-terminal repeat–containing region and whether it was paired with native PP1 purified from rabbit muscle or recombinant PP1 purified from bacteria. Furthermore, none of the PPP1R15A-containing holophosphatases tested were inhibited by Sephin1 or guanabenz.
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Affiliation(s)
- Ana Crespillo-Casado
- From the Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, United Kingdom,
| | - Zander Claes
- the Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium, and
| | - Meng S Choy
- the Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721-0041
| | - Wolfgang Peti
- the Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721-0041
| | - Mathieu Bollen
- the Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium, and
| | - David Ron
- From the Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, United Kingdom,
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21
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Chourabi M, Liew MS, Lim S, H’mida-Ben Brahim D, Boussofara L, Dai L, Wong PM, Foo JN, Sriha B, Robinson KS, Denil S, Common JEA, Mamaï O, Ben Khalifa Y, Bollen M, Liu J, Denguezli M, Bonnard C, Saad A, Reversade B. ENPP1 Mutation Causes Recessive Cole Disease by Altering Melanogenesis. J Invest Dermatol 2018; 138:291-300. [DOI: 10.1016/j.jid.2017.08.045] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 08/14/2017] [Accepted: 08/16/2017] [Indexed: 10/18/2022]
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22
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Gelens L, Qian J, Bollen M, Saurin AT. The Importance of Kinase-Phosphatase Integration: Lessons from Mitosis. Trends Cell Biol 2018; 28:6-21. [PMID: 29089159 DOI: 10.1016/j.tcb.2017.09.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 09/26/2017] [Accepted: 09/26/2017] [Indexed: 12/20/2022]
Abstract
Kinases and phosphatases work antagonistically to control the behaviour of individual substrate molecules. This can be incorrectly extrapolated to imply that they also work antagonistically on the signals or processes that these molecules control. In fact, in many situations kinases and phosphatases work together to positively drive signal responses. We explain how this 'cooperativity' is critical for setting the amplitude, localisation, timing, and shape of phosphorylation signals. We use mitosis to illustrate why these properties are important for controlling mitotic entry, sister chromatid cohesion, kinetochore-microtubule attachments, the spindle assembly checkpoint, mitotic spindle elongation, and mitotic exit. These examples provide a rationale to explain how complex signalling behaviour could rely on similar types of integration within many other biological processes.
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Affiliation(s)
- Lendert Gelens
- Laboratory of Dynamics in Biological Systems, Department of Cellular and Molecular Medicine, University of Leuven, 3000 Leuven, Belgium.
| | - Junbin Qian
- Laboratory of Biosignaling and Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, Belgium
| | - Mathieu Bollen
- Laboratory of Biosignaling and Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, Belgium
| | - Adrian T Saurin
- Division of Cancer Research, School of Medicine, Jacqui Wood Cancer Centre, Ninewells Hospital and Medical School, University of Dundee, Dundee, DD1 9SY, UK.
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23
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Kig C, Beullens M, Beke L, Van Eynde A, Linders JT, Brehmer D, Bollen M. Maternal embryonic leucine zipper kinase (MELK) reduces replication stress in glioblastoma cells. J Biol Chem 2017; 292:12786. [PMID: 28778883 DOI: 10.1074/jbc.a113.471433] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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24
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De Munter S, Görnemann J, Derua R, Lesage B, Qian J, Heroes E, Waelkens E, Van Eynde A, Beullens M, Bollen M. Split-BioID: a proximity biotinylation assay for dimerization-dependent protein interactions. FEBS Lett 2017; 591:415-424. [DOI: 10.1002/1873-3468.12548] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 12/03/2016] [Accepted: 12/26/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Sofie De Munter
- Laboratory of Biosignaling & Therapeutics; KU Leuven Department of Cellular and Molecular Medicine; University of Leuven; Belgium
| | - Janina Görnemann
- Laboratory of Biosignaling & Therapeutics; KU Leuven Department of Cellular and Molecular Medicine; University of Leuven; Belgium
| | - Rita Derua
- Protein Phosphorylation & Proteomics Lab; KU Leuven Department of Cellular and Molecular Medicine; University of Leuven; Belgium
- SyBioMa; KU Leuven; Belgium
| | - Bart Lesage
- Laboratory of Biosignaling & Therapeutics; KU Leuven Department of Cellular and Molecular Medicine; University of Leuven; Belgium
| | - Junbin Qian
- Laboratory of Biosignaling & Therapeutics; KU Leuven Department of Cellular and Molecular Medicine; University of Leuven; Belgium
| | - Ewald Heroes
- Laboratory of Biosignaling & Therapeutics; KU Leuven Department of Cellular and Molecular Medicine; University of Leuven; Belgium
| | - Etienne Waelkens
- Protein Phosphorylation & Proteomics Lab; KU Leuven Department of Cellular and Molecular Medicine; University of Leuven; Belgium
- SyBioMa; KU Leuven; Belgium
| | - Aleyde Van Eynde
- Laboratory of Biosignaling & Therapeutics; KU Leuven Department of Cellular and Molecular Medicine; University of Leuven; Belgium
| | - Monique Beullens
- Laboratory of Biosignaling & Therapeutics; KU Leuven Department of Cellular and Molecular Medicine; University of Leuven; Belgium
| | - Mathieu Bollen
- Laboratory of Biosignaling & Therapeutics; KU Leuven Department of Cellular and Molecular Medicine; University of Leuven; Belgium
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25
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Wang X, Bajaj R, Bollen M, Peti W, Page R. Expanding the PP2A Interactome by Defining a B56-Specific SLiM. Structure 2016; 24:2174-2181. [PMID: 27998540 DOI: 10.1016/j.str.2016.09.010] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 08/11/2016] [Accepted: 10/03/2016] [Indexed: 11/18/2022]
Abstract
Specific interactions between proteins govern essential physiological processes including signaling. Many enzymes, especially the family of serine/threonine phosphatases (PSPs: PP1, PP2A, and PP2B/calcineurin/CN), recruit substrates and regulatory proteins by binding short linear motifs (SLiMs), short sequences found within intrinsically disordered regions that mediate specific protein-protein interactions. While tremendous progress had been made in identifying where and how SLiMs bind PSPs, especially PP1 and CN, essentially nothing is known about how SLiMs bind PP2A, a validated cancer drug target. Here we describe three structures of a PP2A-SLiM interaction (B56:pS-RepoMan, B56:pS-BubR1, and B56:pSpS-BubR1), show that this PP2A-specific SLiM is defined as LSPIxE, and then use these data to discover scores of likely PP2A regulators and substrates. Together, these data provide a powerful approach not only for dissecting PP2A interaction networks in cells but also for targeting PP2A diseases, such as cancer.
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Affiliation(s)
- Xinru Wang
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912, USA
| | - Rakhi Bajaj
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912, USA
| | - Mathieu Bollen
- Laboratory of Biosignaling & Therapeutics, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Wolfgang Peti
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, Providence, RI 02912, USA; Department Chemistry, Brown University, Providence, RI 02912, USA
| | - Rebecca Page
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912, USA.
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26
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Kumar GS, Gokhan E, De Munter S, Bollen M, Vagnarelli P, Peti W, Page R. The Ki-67 and RepoMan mitotic phosphatases assemble via an identical, yet novel mechanism. eLife 2016; 5. [PMID: 27572260 PMCID: PMC5005033 DOI: 10.7554/elife.16539] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 08/16/2016] [Indexed: 12/26/2022] Open
Abstract
Ki-67 and RepoMan have key roles during mitotic exit. Previously, we showed that Ki-67 organizes the mitotic chromosome periphery and recruits protein phosphatase 1 (PP1) to chromatin at anaphase onset, in a similar manner as RepoMan (Booth et al., 2014). Here we show how Ki-67 and RepoMan form mitotic exit phosphatases by recruiting PP1, how they distinguish between distinct PP1 isoforms and how the assembly of these two holoenzymes are dynamically regulated by Aurora B kinase during mitosis. Unexpectedly, our data also reveal that Ki-67 and RepoMan bind PP1 using an identical, yet novel mechanism, interacting with a PP1 pocket that is engaged only by these two PP1 regulators. These findings not only show how two distinct mitotic exit phosphatases are recruited to their substrates, but also provide immediate opportunities for the design of novel cancer therapeutics that selectively target the Ki-67:PP1 and RepoMan:PP1 holoenzymes.
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Affiliation(s)
- Ganesan Senthil Kumar
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, Providence, United States
| | - Ezgi Gokhan
- College of Health and Life Science, Research Institute for Environment, Health and Society, Brunel University London, Uxbridge, United Kingdom
| | - Sofie De Munter
- Laboratory of Biosignaling and Therapeutics, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Mathieu Bollen
- Laboratory of Biosignaling and Therapeutics, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Paola Vagnarelli
- College of Health and Life Science, Research Institute for Environment, Health and Society, Brunel University London, Uxbridge, United Kingdom
| | - Wolfgang Peti
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, Providence, United States
| | - Rebecca Page
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, United States
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27
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Boens S, Verbinnen I, Verhulst S, Szekér K, Ferreira M, Gevaert T, Baes M, Roskams T, van Grunsven LA, Van Eynde A, Bollen M. Brief Report: The Deletion of the Phosphatase Regulator NIPP1 Causes Progenitor Cell Expansion in the Adult Liver. Stem Cells 2016; 34:2256-62. [PMID: 27068806 DOI: 10.1002/stem.2375] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 02/17/2016] [Accepted: 03/14/2016] [Indexed: 01/10/2023]
Abstract
The Ppp1r8 gene encodes NIPP1, a nuclear interactor of protein phosphatase PP1. The deletion of NIPP1 is embryonic lethal at the gastrulation stage, which has hampered its functional characterization in adult tissues. Here, we describe the effects of a conditional deletion of NIPP1 in mouse liver epithelial cells. Ppp1r8(-/-) livers developed a ductular reaction, that is, bile-duct hyperplasia with associated fibrosis. The increased proliferation of biliary epithelial cells was at least partially due to an expansion of the progenitor cell compartment that was independent of liver injury. Gene-expression analysis confirmed an upregulation of progenitor cell markers in the liver knockout livers but showed no effect on the expression of liver-injury associated regulators of cholangiocyte differentiation markers. Consistent with an inhibitory effect of NIPP1 on progenitor cell proliferation, Ppp1r8(-/-) livers displayed an increased sensitivity to diet-supplemented 3,5-diethoxycarbonyl-1,4-dihydrocollidine, which also causes bile-duct hyperplasia through progenitor cell expansion. In contrast, the liver knockouts responded normally to injuries (partial hepatectomy, single CCl4 administration) that are restored through proliferation of differentiated parenchymal cells. Our data indicate that NIPP1 does not regulate the proliferation of hepatocytes but is a suppressor of biliary epithelial cell proliferation, including progenitor cells, in the adult liver. Stem Cells 2016;34:2256-2262.
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Affiliation(s)
- Shannah Boens
- Department of Cellular and Molecular Medicine, Laboratory of Biosignaling & Therapeutics, KU Leuven, Belgium
| | - Iris Verbinnen
- Department of Cellular and Molecular Medicine, Laboratory of Biosignaling & Therapeutics, KU Leuven, Belgium
| | - Stefaan Verhulst
- Liver Cell Biology Lab, Vrije Universiteit Brussel, Brussel, Belgium
| | - Kathelijne Szekér
- Department of Cellular and Molecular Medicine, Laboratory of Biosignaling & Therapeutics, KU Leuven, Belgium
| | - Monica Ferreira
- Department of Cellular and Molecular Medicine, Laboratory of Biosignaling & Therapeutics, KU Leuven, Belgium
| | - Thomas Gevaert
- Department of Development and Regeneration, Organ Systems, KU Leuven, Belgium
| | - Myriam Baes
- Department of Pharmaceutical & Pharmacological Sciences, Laboratory for Cell Metabolism, KU Leuven, Belgium
| | - Tania Roskams
- Department of Imaging & Pathology, Laboratory of Translational Cell & Tissue Research, KU Leuven, Belgium
| | | | - Aleyde Van Eynde
- Department of Cellular and Molecular Medicine, Laboratory of Biosignaling & Therapeutics, KU Leuven, Belgium
| | - Mathieu Bollen
- Department of Cellular and Molecular Medicine, Laboratory of Biosignaling & Therapeutics, KU Leuven, Belgium
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28
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Rambout X, Detiffe C, Bruyr J, Mariavelle E, Cherkaoui M, Brohée S, Demoitié P, Lebrun M, Soin R, Lesage B, Guedri K, Beullens M, Bollen M, Farazi TA, Kettmann R, Struman I, Hill DE, Vidal M, Kruys V, Simonis N, Twizere JC, Dequiedt F. The transcription factor ERG recruits CCR4-NOT to control mRNA decay and mitotic progression. Nat Struct Mol Biol 2016; 23:663-72. [PMID: 27273514 DOI: 10.1038/nsmb.3243] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 05/13/2016] [Indexed: 01/08/2023]
Abstract
Control of mRNA levels, a fundamental aspect in the regulation of gene expression, is achieved through a balance between mRNA synthesis and decay. E26-related gene (Erg) proteins are canonical transcription factors whose previously described functions are confined to the control of mRNA synthesis. Here, we report that ERG also regulates gene expression by affecting mRNA stability and identify the molecular mechanisms underlying this function in human cells. ERG is recruited to mRNAs via interaction with the RNA-binding protein RBPMS, and it promotes mRNA decay by binding CNOT2, a component of the CCR4-NOT deadenylation complex. Transcriptome-wide mRNA stability analysis revealed that ERG controls the degradation of a subset of mRNAs highly connected to Aurora signaling, whose decay during S phase is necessary for mitotic progression. Our data indicate that control of gene expression by mammalian transcription factors may follow a more complex scheme than previously anticipated, integrating mRNA synthesis and degradation.
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Affiliation(s)
- Xavier Rambout
- Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of Liège (ULg), Liège, Belgium.,GIGA-Molecular Biology in Diseases, ULg, Liège, Belgium
| | - Cécile Detiffe
- Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of Liège (ULg), Liège, Belgium.,GIGA-Molecular Biology in Diseases, ULg, Liège, Belgium
| | - Jonathan Bruyr
- Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of Liège (ULg), Liège, Belgium.,GIGA-Molecular Biology in Diseases, ULg, Liège, Belgium
| | - Emeline Mariavelle
- Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of Liège (ULg), Liège, Belgium.,GIGA-Molecular Biology in Diseases, ULg, Liège, Belgium
| | - Majid Cherkaoui
- Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of Liège (ULg), Liège, Belgium.,GIGA-Molecular Biology in Diseases, ULg, Liège, Belgium
| | - Sylvain Brohée
- BiGRe, Université Libre de Bruxelles (ULB), Bruxelles, Belgium.,Computer Science Department, ULB, Bruxelles, Belgium
| | - Pauline Demoitié
- Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of Liège (ULg), Liège, Belgium.,GIGA-Molecular Biology in Diseases, ULg, Liège, Belgium
| | - Marielle Lebrun
- Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of Liège (ULg), Liège, Belgium.,GIGA-Inflammation, Infection &Immunity, ULg, Liège, Belgium
| | | | - Bart Lesage
- Department of Cellular and Molecular Medicine, University of Leuven (KUL), Leuven, Belgium
| | - Katia Guedri
- Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of Liège (ULg), Liège, Belgium.,GIGA-Molecular Biology in Diseases, ULg, Liège, Belgium
| | - Monique Beullens
- Department of Cellular and Molecular Medicine, University of Leuven (KUL), Leuven, Belgium
| | - Mathieu Bollen
- Department of Cellular and Molecular Medicine, University of Leuven (KUL), Leuven, Belgium
| | - Thalia A Farazi
- Howard Hughes Medical Institute, Rockefeller University, New York, New York, USA
| | - Richard Kettmann
- Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of Liège (ULg), Liège, Belgium.,GIGA-Molecular Biology in Diseases, ULg, Liège, Belgium
| | - Ingrid Struman
- Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of Liège (ULg), Liège, Belgium.,GIGA-Cancer, ULg, Liège, Belgium
| | - David E Hill
- Center for Cancer Systems Biology (CCSB), Department of Cancer Biology, Dana-Farber Cancer Institute (DFCI), Boston, Massachusetts, USA.,Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA
| | - Marc Vidal
- Center for Cancer Systems Biology (CCSB), Department of Cancer Biology, Dana-Farber Cancer Institute (DFCI), Boston, Massachusetts, USA.,Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA
| | | | - Nicolas Simonis
- BiGRe, Université Libre de Bruxelles (ULB), Bruxelles, Belgium
| | - Jean-Claude Twizere
- Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of Liège (ULg), Liège, Belgium.,GIGA-Molecular Biology in Diseases, ULg, Liège, Belgium
| | - Franck Dequiedt
- Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of Liège (ULg), Liège, Belgium.,GIGA-Molecular Biology in Diseases, ULg, Liège, Belgium
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29
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Quan XJ, Yuan L, Tiberi L, Claeys A, De Geest N, Yan J, van der Kant R, Xie W, Klisch T, Shymkowitz J, Rousseau F, Bollen M, Beullens M, Zoghbi H, Vanderhaeghen P, Hassan B. Post-translational Control of the Temporal Dynamics of Transcription Factor Activity Regulates Neurogenesis. Cell 2016; 164:460-75. [DOI: 10.1016/j.cell.2015.12.048] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 10/12/2015] [Accepted: 12/22/2015] [Indexed: 11/28/2022]
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30
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Qian J, Beullens M, Huang J, De Munter S, Lesage B, Bollen M. Cdk1 orders mitotic events through coordination of a chromosome-associated phosphatase switch. Nat Commun 2015; 6:10215. [PMID: 26674376 PMCID: PMC4703885 DOI: 10.1038/ncomms10215] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 11/13/2015] [Indexed: 02/08/2023] Open
Abstract
RepoMan is a scaffold for signalling by mitotic phosphatases at the chromosomes. During (pro)metaphase, RepoMan-associated protein phosphatases PP1 and PP2A-B56 regulate the chromosome targeting of Aurora-B kinase and RepoMan, respectively. Here we show that this task division is critically dependent on the phosphorylation of RepoMan by protein kinase Cyclin-dependent kinase 1 (Cdk1), which reduces the binding of PP1 but facilitates the recruitment of PP2A-B56. The inactivation of Cdk1 in early anaphase reverses this phosphatase switch, resulting in the accumulation of PP1-RepoMan to a level that is sufficient to catalyse its own chromosome targeting in a PP2A-independent and irreversible manner. Bulk-targeted PP1-RepoMan also inactivates Aurora B and initiates nuclear-envelope reassembly through dephosphorylation-mediated recruitment of Importin β. Bypassing the Cdk1 regulation of PP1-RepoMan causes the premature dephosphorylation of its mitotic-exit substrates in prometaphase. Hence, the regulation of RepoMan-associated phosphatases by Cdk1 is essential for the timely dephosphorylation of their mitotic substrates. RepoMan is a signalling scaffold for mitotic phosphatases PP1 and PP2A-B56, which regulate targeting of Aurora B and RepoMan respectively, to the chromosomes. Here Qian et al. show that Cdk1 phosphorylates RepoMan to modulate the binding of PP1 and PP2A-B56, contributing to orderly mitotic progression.
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Affiliation(s)
- Junbin Qian
- Laboratory of Biosignaling &Therapeutics, Department of Cellular and Molecular Medicine, University of Leuven, Campus Gasthuisberg, O&N1, Herestraat 49, Box 901, Leuven B-3000, Belgium
| | - Monique Beullens
- Laboratory of Biosignaling &Therapeutics, Department of Cellular and Molecular Medicine, University of Leuven, Campus Gasthuisberg, O&N1, Herestraat 49, Box 901, Leuven B-3000, Belgium
| | - Jin Huang
- Laboratory of Biosignaling &Therapeutics, Department of Cellular and Molecular Medicine, University of Leuven, Campus Gasthuisberg, O&N1, Herestraat 49, Box 901, Leuven B-3000, Belgium.,Department of Biochemistry and Molecular Biology, Guizhou Medical University, Guiyang, Guizhou 550025, China
| | - Sofie De Munter
- Laboratory of Biosignaling &Therapeutics, Department of Cellular and Molecular Medicine, University of Leuven, Campus Gasthuisberg, O&N1, Herestraat 49, Box 901, Leuven B-3000, Belgium
| | - Bart Lesage
- Laboratory of Biosignaling &Therapeutics, Department of Cellular and Molecular Medicine, University of Leuven, Campus Gasthuisberg, O&N1, Herestraat 49, Box 901, Leuven B-3000, Belgium
| | - Mathieu Bollen
- Laboratory of Biosignaling &Therapeutics, Department of Cellular and Molecular Medicine, University of Leuven, Campus Gasthuisberg, O&N1, Herestraat 49, Box 901, Leuven B-3000, Belgium
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31
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Winkler C, De Munter S, Van Dessel N, Lesage B, Heroes E, Boens S, Beullens M, Van Eynde A, Bollen M. The selective inhibition of protein phosphatase-1 results in mitotic catastrophe and impaired tumor growth. J Cell Sci 2015; 128:4526-37. [PMID: 26542020 DOI: 10.1242/jcs.175588] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 10/26/2015] [Indexed: 01/07/2023] Open
Abstract
The serine/threonine protein phosphatase-1 (PP1) complex is a key regulator of the cell cycle. However, the redundancy of PP1 isoforms and the lack of specific inhibitors have hampered studies on the global role of PP1 in cell cycle progression in vertebrates. Here, we show that the overexpression of nuclear inhibitor of PP1 (NIPP1; also known as PPP1R8) in HeLa cells culminated in a prometaphase arrest, associated with severe spindle-formation and chromosome-congression defects. In addition, the spindle assembly checkpoint was activated and checkpoint silencing was hampered. Eventually, most cells either died by apoptosis or formed binucleated cells. The NIPP1-induced mitotic arrest could be explained by the inhibition of PP1 that was titrated away from other mitotic PP1 interactors. Consistent with this notion, the mitotic-arrest phenotype could be rescued by the overexpression of PP1 or the inhibition of the Aurora B kinase, which acts antagonistically to PP1. Finally, we demonstrate that the overexpression of NIPP1 also hampered colony formation and tumor growth in xenograft assays in a PP1-dependent manner. Our data show that the selective inhibition of PP1 can be used to induce cancer cell death through mitotic catastrophe.
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Affiliation(s)
- Claudia Winkler
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, Leuven B-3000, Belgium
| | - Sofie De Munter
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, Leuven B-3000, Belgium
| | - Nele Van Dessel
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, Leuven B-3000, Belgium
| | - Bart Lesage
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, Leuven B-3000, Belgium
| | - Ewald Heroes
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, Leuven B-3000, Belgium
| | - Shannah Boens
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, Leuven B-3000, Belgium
| | - Monique Beullens
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, Leuven B-3000, Belgium
| | - Aleyde Van Eynde
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, Leuven B-3000, Belgium
| | - Mathieu Bollen
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, Leuven B-3000, Belgium
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32
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Verheyen T, Görnemann J, Verbinnen I, Boens S, Beullens M, Van Eynde A, Bollen M. Genome-wide promoter binding profiling of protein phosphatase-1 and its major nuclear targeting subunits. Nucleic Acids Res 2015; 43:5771-84. [PMID: 25990731 PMCID: PMC4499128 DOI: 10.1093/nar/gkv500] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 05/05/2015] [Indexed: 12/11/2022] Open
Abstract
Protein phosphatase-1 (PP1) is a key regulator of transcription and is targeted to promoter regions via associated proteins. However, the chromatin binding sites of PP1 have never been studied in a systematic and genome-wide manner. Methylation-based DamID profiling in HeLa cells has enabled us to map hundreds of promoter binding sites of PP1 and three of its major nuclear interactors, i.e. RepoMan, NIPP1 and PNUTS. Our data reveal that the α, β and γ isoforms of PP1 largely bind to distinct subsets of promoters and can also be differentiated by their promoter binding pattern. PP1β emerged as the major promoter-associated isoform and shows an overlapping binding profile with PNUTS at dozens of active promoters. Surprisingly, most promoter binding sites of PP1 are not shared with RepoMan, NIPP1 or PNUTS, hinting at the existence of additional, largely unidentified chromatin-targeting subunits. We also found that PP1 is not required for the global chromatin targeting of RepoMan, NIPP1 and PNUTS, but alters the promoter binding specificity of NIPP1. Our data disclose an unexpected specificity and complexity in the promoter binding of PP1 isoforms and their chromatin-targeting subunits.
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Affiliation(s)
- Toon Verheyen
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Janina Görnemann
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Iris Verbinnen
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Shannah Boens
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Monique Beullens
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Aleyde Van Eynde
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Mathieu Bollen
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
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33
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Heroes E, Rip J, Beullens M, Van Meervelt L, De Gendt S, Bollen M. Metals in the active site of native protein phosphatase-1. J Inorg Biochem 2015; 149:1-5. [PMID: 25890482 DOI: 10.1016/j.jinorgbio.2015.03.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 03/23/2015] [Accepted: 03/24/2015] [Indexed: 11/26/2022]
Abstract
Protein phosphatase-1 (PP1) is a major protein Ser/Thr phosphatase in eukaryotic cells. Its activity depends on two metal ions in the catalytic site, which were identified as manganese in the bacterially expressed phosphatase. However, the identity of the metal ions in native PP1 is unknown. In this study, total reflection X-ray fluorescence (TXRF) was used to detect iron and zinc in PP1 that was purified from rabbit skeletal muscle. Metal exchange experiments confirmed that the distinct substrate specificity of recombinant and native PP1 is determined by the nature of their associated metals. We also found that the iron level associated with native PP1 is decreased by incubation with inhibitor-2, consistent with a function of inhibitor-2 as a PP1 chaperone.
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Affiliation(s)
- Ewald Heroes
- Laboratory of Biosignaling and Therapeutics, Department of Cellular and Molecular Medicine, KU Leuven, Belgium; Department of Chemistry, KU Leuven, Belgium
| | - Jens Rip
- Interuniversity Micro Electronics Center (IMEC), Leuven, Belgium
| | - Monique Beullens
- Laboratory of Biosignaling and Therapeutics, Department of Cellular and Molecular Medicine, KU Leuven, Belgium
| | | | - Stefan De Gendt
- Department of Chemistry, KU Leuven, Belgium; Interuniversity Micro Electronics Center (IMEC), Leuven, Belgium
| | - Mathieu Bollen
- Laboratory of Biosignaling and Therapeutics, Department of Cellular and Molecular Medicine, KU Leuven, Belgium.
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Litovkin K, Joniau S, Lerut E, Laenen A, Gevaert O, Spahn M, Kneitz B, Isebaert S, Haustermans K, Beullens M, Van Eynde A, Bollen M. Methylation of PITX2, HOXD3, RASSF1 and TDRD1 predicts biochemical recurrence in high-risk prostate cancer. J Cancer Res Clin Oncol 2014; 140:1849-61. [PMID: 24938434 DOI: 10.1007/s00432-014-1738-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 06/05/2014] [Indexed: 10/25/2022]
Abstract
PURPOSE To explore differential methylation of HAAO, HOXD3, LGALS3, PITX2, RASSF1 and TDRD1 as a molecular tool to predict biochemical recurrence (BCR) in patients with high-risk prostate cancer (PCa). METHODS A multiplexed nested methylation-specific PCR was applied to quantify promoter methylation of the selected markers in five cell lines, 42 benign prostatic hyperplasia (BPH) and 71 high-risk PCa tumor samples. Uni- and multivariate Cox regression models were used to assess the importance of the methylation level in predicting BCR. RESULTS A PCa-specific methylation marker HAAO in combination with HOXD3 and a hypomethylation marker TDRD1 distinguished PCa samples (>90 % of tumor cells each) from BPH with a sensitivity of 0.99 and a specificity of 0.95. High methylation of PITX2, HOXD3 and RASSF1, as well as low methylation of TDRD1, appeared to be significantly associated with a higher risk for BCR (HR 3.96, 3.44, 2.80 and 2.85, correspondingly) after correcting for established risk factors. When DNA methylation was treated as a continuous variable, a two-gene model PITX2 × 0.020677 + HOXD3 × 0.0043132 proved to be the best predictor of BCR (HR 4.85) compared with the individual markers. This finding was confirmed in an independent set of 52 high-risk PCa tumor samples (HR 11.89). CONCLUSIONS Differential promoter methylation of HOXD3, PITX2, RASSF1 and TDRD1 emerges as an independent predictor of BCR in high-risk PCa patients. A two-gene continuous DNA methylation model "PITX2 × 0.020677 + HOXD3 × 0.0043132" is a better predictor of BCR compared with individual markers.
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Affiliation(s)
- Kirill Litovkin
- Laboratory of Biosignaling and Therapeutics, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium,
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Eiteneuer A, Seiler J, Weith M, Beullens M, Lesage B, Krenn V, Musacchio A, Bollen M, Meyer H. Inhibitor-3 ensures bipolar mitotic spindle attachment by limiting association of SDS22 with kinetochore-bound protein phosphatase-1. EMBO J 2014; 33:2704-20. [PMID: 25298395 DOI: 10.15252/embj.201489054] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Faithful chromosome segregation during mitosis is tightly regulated by opposing activities of Aurora B kinase and protein phosphatase-1 (PP1). PP1 function at kinetochores has been linked to SDS22, but the exact localization of SDS22 and how it affects PP1 are controversial. Here, we confirm that SDS22 is required for PP1 activity, but show that SDS22 does not normally localize to kinetochores. Instead, SDS22 is kept in solution by formation of a ternary complex with PP1 and inhibitor-3 (I3). Depletion of I3 does not affect the amount of PP1 at kinetochores but causes quantitative association of SDS22 with PP1 on KNL1 at the kinetochore. Such accumulation of SDS22 at kinetochores interferes with PP1 activity and inhibits Aurora B threonine-232 dephosphorylation, which leads to increased Aurora B activity in metaphase and persistence in anaphase accompanied with segregation defects. We propose a model in which I3 regulates an SDS22-mediated PP1 activation step in solution that precedes SDS22 dissociation and transfer of PP1 to kinetochores, and which is required for PP1 to efficiently antagonize Aurora B.
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Affiliation(s)
- Annika Eiteneuer
- Centre for Medical Biotechnology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany
| | - Jonas Seiler
- Centre for Medical Biotechnology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany
| | - Matthias Weith
- Centre for Medical Biotechnology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany
| | - Monique Beullens
- Laboratory of Biosignaling & Therapeutics, KU Leuven, Department of Cellular and Molecular Medicine, University of Leuven, Leuven, Belgium
| | - Bart Lesage
- Laboratory of Biosignaling & Therapeutics, KU Leuven, Department of Cellular and Molecular Medicine, University of Leuven, Leuven, Belgium
| | - Veronica Krenn
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Andrea Musacchio
- Centre for Medical Biotechnology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Mathieu Bollen
- Laboratory of Biosignaling & Therapeutics, KU Leuven, Department of Cellular and Molecular Medicine, University of Leuven, Leuven, Belgium
| | - Hemmo Meyer
- Centre for Medical Biotechnology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany
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Beke L, Linders JT, Kig C, Boeckx A, Heerde EV, Wuyts D, Parade M, Meerpoel L, Johnson C, Beullens M, Bollen M, Brehmer D. Abstract 2936: JNJ-47117096, a selective small molecule inhibitor of the MELK oncogene decreases DNA damage tolerance in highly proliferating cancer cells. Cancer Res 2014. [DOI: 10.1158/1538-7445.am2014-2936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Maternal embryonic leucine zipper kinase (MELK, hMP38, pEG3), a Ser/Thr protein kinase, is highly overexpressed in stem cells and cancer cells. The oncogenic role of MELK is attributed to disabling critical cell cycle check points as well as enhancing replication. Most functional studies have relied on the use of siRNA/shRNA mediated gene silencing, but this often can be associated with off-target effects.
Here we want to present a novel, potent and selective small molecule inhibitor JNJ-47117096 that has enabled us to validate the biological function of MELK kinase.
Outcome: MELK inhibition in cancer cells with an intact p53 signaling pathway is linked to a replicative senescence phenotype. This phenotype correlates with a rapid ATM activation and phosphorylation of CHK2 without any effects on the alternative ATR/ CHK1 DNA damage pathways. Furthermore, JNJ-47117096 induces strong phosphorylation of p53 and prolonged up-regulation of p21 without the induction of apoptosis. Strikingly, MELK inhibition in several p53 disabled cancer cells showed induction of a mitotic catastrophe phenotype followed by prominent cell killing.
Finally, JNJ-47117096 triggers a rapid degradation of cellular MELK protein, independent of the cell cycle phase and its regulation by the E2F pathway. This observation can clearly be linked to a direct binding effect of JNJ-47117096 to cellular MELK protein confirmed by chemical proteomics.
Conclusion: Our data generated with JNJ-47117096, confirmed by selective siRNAs, indicate MELK as a key stimulator of proliferation and replication by its ability to increase the threshold for DNA damage tolerance. Targeting MELK function by selective small molecule inhibitors might sensitise tumors to DNA-damaging agents or radiation therapy.
Citation Format: Lijs Beke, Joannes T.m. Linders, Cenk Kig, An Boeckx, Erika van Heerde, Dirk Wuyts, Marc Parade, Lieven Meerpoel, Chris Johnson, Monique Beullens, Mathieu Bollen, Dirk Brehmer. JNJ-47117096, a selective small molecule inhibitor of the MELK oncogene decreases DNA damage tolerance in highly proliferating cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2936. doi:10.1158/1538-7445.AM2014-2936
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Affiliation(s)
- Lijs Beke
- 1Oncology Discovery, Janssen Research & Development, a division of Janssen Pharmaceutica NV, Beerse, Belgium
| | - Joannes T.m. Linders
- 1Oncology Discovery, Janssen Research & Development, a division of Janssen Pharmaceutica NV, Beerse, Belgium
| | - Cenk Kig
- 2Laboratory of Biosignaling & Therapeutics, Department of Cellular and Molecular Medicine, Campus Gasthuisberg, Leuven, Belgium
| | - An Boeckx
- 1Oncology Discovery, Janssen Research & Development, a division of Janssen Pharmaceutica NV, Beerse, Belgium
| | - Erika van Heerde
- 1Oncology Discovery, Janssen Research & Development, a division of Janssen Pharmaceutica NV, Beerse, Belgium
| | - Dirk Wuyts
- 1Oncology Discovery, Janssen Research & Development, a division of Janssen Pharmaceutica NV, Beerse, Belgium
| | - Marc Parade
- 1Oncology Discovery, Janssen Research & Development, a division of Janssen Pharmaceutica NV, Beerse, Belgium
| | - Lieven Meerpoel
- 1Oncology Discovery, Janssen Research & Development, a division of Janssen Pharmaceutica NV, Beerse, Belgium
| | | | - Monique Beullens
- 2Laboratory of Biosignaling & Therapeutics, Department of Cellular and Molecular Medicine, Campus Gasthuisberg, Leuven, Belgium
| | - Mathieu Bollen
- 2Laboratory of Biosignaling & Therapeutics, Department of Cellular and Molecular Medicine, Campus Gasthuisberg, Leuven, Belgium
| | - Dirk Brehmer
- 1Oncology Discovery, Janssen Research & Development, a division of Janssen Pharmaceutica NV, Beerse, Belgium
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Abstract
Mitotic kinetochores coordinate chromosome bi-orientation and anaphase onset by serving as scaffolds for the recruitment of regulatory proteins. Three new studies reveal that multiple interaction motifs of the kinetochore protein Knl1 cooperate to assemble signaling complexes that regulate chromosome segregation.
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Affiliation(s)
- Mathieu Bollen
- Laboratory of Biosignaling and Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium.
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Litovkin K, Joniau S, Lerut E, Laenen A, Gevaert O, Spahn M, Kneitz B, Isebaert S, Haustermans K, Beullens M, Van Eynde A, Bollen M. Methylation-guided stratification of patients with high-risk prostate cancer for the prediction of clinical failure. J Clin Oncol 2014. [DOI: 10.1200/jco.2014.32.4_suppl.155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
155 Background: To explore differential DNA methylation of APC, CCDN2, GSTP1, PTGS2, and RARBas a tool to predict clinical failure (CF) in surgically treated patients with high-risk prostate cancer (PCa), as defined by a clinical stage T3a or higher, a biopsy Gleason score of 8 to 10 and/or pre-operative prostatic serum antigen levels more than 20 ng/ml. Methods: A quantitative multiplex, methylation-specific PCR assay was developed to assess promoter methylation of the marker genes. Formalin-fixed, paraffin-embedded radical prostatectomy samples from 218 patients with high-risk PCa, classified in a training and validation cohort, were analyzed. Kaplan-Meier analysis and Cox multivariate models were used. Results: First, high-risk PCa patients were ranked according to their GSTP1 methylation level, which varied from 0 to 80% in both cohorts. Next, we categorizedthe tumors into three groups based upon the GSTP1 methylation level: low methylation (LM, methylation less than 15%), moderate methylation ([MM], methylation 15 to 50%) and high methylation (HM, methylation more than 50%). When all five marker genes were combined, the median methylation values in the LM groups did not exceed 6% in both cohorts. In contrast, the median methylation values for the marker genes in the HM groups reached 45% in the training cohort and 50% in the validation cohort. Finally, the median methylation values in the MM groups amounted to 18% and 28% for the training and validation cohorts, respectively. Remarkably, patients belonging to the LM, HM, and the combined LM+HM groups had a 2- to 11-fold higher risk of CF as compared to those of the MM group, when correcting for established clinico-pathologic prognostic factors. In addition, the combined LM+HM group showed a significant association with cancer-related death in a multivariate analysis (Hazard ratio, 3.59) compared to the MM group, when both cohorts were combined for analysis. Conclusions: We found that differential methylation of GSTP1 allows the stratification of high-risk PCa patients into three molecular episubtypes, i.e. low, moderate and high DNA methylation level groups. Surprisingly, our data revealed that both low and high methylation levels of GSTP1 are independent predictors of CF.
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Affiliation(s)
- Kirill Litovkin
- Laboratory of Biosignaling & Therapeutics, Departement of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Steven Joniau
- Urology, Department of Development and Regeneration, University Hospitals Leuven, Leuven, Belgium
| | - Evelyne Lerut
- Department of Pathology, University Hospitals Leuven, Leuven, Belgium
| | - Annouschka Laenen
- Leuven Biostatistics and Btatistical Bioinformatics Centre, KU Leuven, Leuven, Belgium
| | - Olivier Gevaert
- Stanford Center for Cancer Systems Biology, Stanford University School of Medicine, Stanford, CA
| | - Martin Spahn
- Department of Urology, University Hospital Bern, Inselspital, Bern, Switzerland
| | - Burkhard Kneitz
- Department of Urology and Paediatric Urology, University Hospitpal, Würzburg, Germany
| | - Sofie Isebaert
- Radiation Oncology, University Hospitals Leuven & Department oncology, KU Leuven, Leuven, Belgium
| | - Karin Haustermans
- Radiation Oncology, University Hospitals Leuven & Department of Oncology, KU Leuven, Leuven, Belgium
| | - Monique Beullens
- Laboratory of Biosignaling & Therapeutics, Departement of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Aleyde Van Eynde
- Laboratory of Biosignaling & Therapeutics, Departement of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Mathieu Bollen
- Laboratory of Biosignaling & Therapeutics, Departement of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
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Qian J, Winkler C, Bollen M. 4D-networking by mitotic phosphatases. Curr Opin Cell Biol 2013; 25:697-703. [DOI: 10.1016/j.ceb.2013.06.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2013] [Revised: 06/14/2013] [Accepted: 06/18/2013] [Indexed: 01/21/2023]
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Reither G, Chatterjee J, Beullens M, Bollen M, Schultz C, Köhn M. Chemical Activators of Protein Phosphatase-1 Induce Calcium Release inside Intact Cells. ACTA ACUST UNITED AC 2013; 20:1179-86. [DOI: 10.1016/j.chembiol.2013.07.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 07/08/2013] [Accepted: 07/12/2013] [Indexed: 01/15/2023]
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Kig C, Beullens M, Beke L, Van Eynde A, Linders JT, Brehmer D, Bollen M. Maternal embryonic leucine zipper kinase (MELK) reduces replication stress in glioblastoma cells. J Biol Chem 2013; 288:24200-12. [PMID: 23836907 DOI: 10.1074/jbc.m113.471433] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Maternal embryonic leucine zipper kinase (MELK) belongs to the subfamily of AMP-activated Ser/Thr protein kinases. The expression of MELK is very high in glioblastoma-type brain tumors, but it is not clear how this contributes to tumor growth. Here we show that the siRNA-mediated loss of MELK in U87 MG glioblastoma cells causes a G1/S phase cell cycle arrest accompanied by cell death or a senescence-like phenotype that can be rescued by the expression of siRNA-resistant MELK. This cell cycle arrest is mediated by an increased expression of p21(WAF1/CIP1), an inhibitor of cyclin-dependent kinases, and is associated with the hypophosphorylation of the retinoblastoma protein and the down-regulation of E2F target genes. The increased expression of p21 can be explained by the consecutive activation of ATM (ataxia telangiectasia mutated), Chk2, and p53. Intriguingly, the activation of p53 in MELK-deficient cells is not due to an increased stability of p53 but stems from the loss of MDMX (mouse double minute-X), an inhibitor of p53 transactivation. The activation of the ATM-Chk2 pathway in MELK-deficient cells is associated with the accumulation of DNA double-strand breaks during replication, as demonstrated by the appearance of γH2AX foci. Replication stress in these cells is also illustrated by an increased number of stalled replication forks and a reduced fork progression speed. Our data indicate that glioblastoma cells have elevated MELK protein levels to better cope with replication stress during unperturbed S phase. Hence, MELK inhibitors hold great potential for the treatment of glioblastomas as such or in combination with DNA-damaging therapies.
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Affiliation(s)
- Cenk Kig
- Laboratory of Biosignaling and Therapeutics, Department of Cellular and Molecular Medicine, University of Leuven, 3000 Leuven, Belgium
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Qian J, Beullens M, Lesage B, Bollen M. Aurora B defines its own chromosomal targeting by opposing the recruitment of the phosphatase scaffold Repo-Man. Curr Biol 2013; 23:1136-43. [PMID: 23746640 DOI: 10.1016/j.cub.2013.05.017] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Revised: 04/19/2013] [Accepted: 05/08/2013] [Indexed: 12/24/2022]
Abstract
Aurora B is the catalytic subunit of the chromosomal passenger complex (CPC), which coordinates mitotic processes through phosphorylation of key regulatory proteins. In prometaphase, the CPC is enriched at the centromeres to regulate the spindle checkpoint and kinetochore-microtubule interactions. Centromeric CPC binds to histone H3 that is phosphorylated at T3 (H3T3ph) by Aurora B-stimulated Haspin. PP1/Repo-Man acts antagonistically to Haspin and dephosphorylates H3T3ph at the chromosome arms but is somehow prevented from causing a net dephosphorylation of centromeric H3T3ph during prometaphase. Here, we show that Aurora B phosphorylates Repo-Man at S893, preventing its recruitment by histones. We also identify PP2A as a mitotic interactor of Repo-Man that dephosphorylates S893 and thereby promotes the targeting of Repo-Man to chromosomes and the dephosphorylation of H3T3ph by PP1. Thus, Repo-Man-associated PP1 and PP2A collaborate to oppose the chromosomal targeting of Aurora B. We propose that the reciprocal feedback regulation of Haspin and Repo-Man by Aurora B generates a robust bistable response that culminates in the centromeric targeting of the CPC during prometaphase.
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Affiliation(s)
- Junbin Qian
- Laboratory of Biosignaling & Therapeutics, Department of Cellular and Molecular Medicine, University of Leuven, 3000 Leuven, Belgium
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Abstract
Protein phosphatases have both protective and promoting roles in the etiology of diseases. A prominent example is the existence of oncogenic as well as tumor-suppressing protein phosphatases. A few protein phosphatase activity modulators are already applied in therapies. These were however not developed in target-directed approaches, and the recent discovery of phosphatase involvement followed their application in therapy. Nevertheless, these examples demonstrate that small molecules can be generated that modulate the activity of protein phosphatases and are beneficial for the treatment of protein phosphorylation diseases. We describe here strategies for the development of activators and inhibitors of protein phosphatases and clarify some long-standing misconceptions concerning the druggability of these enzymes. Recent developments suggest that it is feasible to design potent and selective protein phosphatase modulators with a therapeutic potential.
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Affiliation(s)
- Sofie De Munter
- Laboratory of Biosignaling & Therapeutics, Department of Cellular and Molecular Medicine, University of Leuven, Leuven, Belgium
| | - Maja Köhn
- Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg,
Germany
| | - Mathieu Bollen
- Laboratory of Biosignaling & Therapeutics, Department of Cellular and Molecular Medicine, University of Leuven, Leuven, Belgium
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Abstract
Protein phosphatase-1 (PP1) is an essential enzyme for every eukaryotic cell and catalyzes more than half of all protein dephosphorylations at serine and threonine residues. The free catalytic subunit of PP1 shows little substrate selectivity but is tightly regulated in vivo by a large variety of structurally unrelated PP1-interacting proteins (PIPs). PIPs form highly specific dimeric or trimeric PP1 holoenzymes by acting as substrates, inhibitors, and/or substrate-specifiers. The surface of PP1 contains many binding sites for short PP1-docking motifs that are combined by PIPs to create a PP1-binding code that is universal, specific, degenerate, nonexclusive, and dynamic. These properties of the PP1-binding code can be used for the rational design of small molecules that disrupt subsets of PP1 holoenzymes and have a therapeutic potential.
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Affiliation(s)
- Shannah Boens
- Laboratory of Biosignaling & Therapeutics, Department of Cellular and Molecular Medicine, University of Leuven, Leuven, Belgium
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Minnebo N, Görnemann J, O'Connell N, Van Dessel N, Derua R, Vermunt MW, Page R, Beullens M, Peti W, Van Eynde A, Bollen M. NIPP1 maintains EZH2 phosphorylation and promoter occupancy at proliferation-related target genes. Nucleic Acids Res 2012; 41:842-54. [PMID: 23241245 PMCID: PMC3553949 DOI: 10.1093/nar/gks1255] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The histone methyltransferase EZH2 regulates cell proliferation and differentiation by silencing Polycomb group target genes. NIPP1, a nuclear regulator of serine/threonine protein phosphatase 1 (PP1), has been implicated in the regulation of EZH2 occupancy at target loci, but the underlying mechanism is not understood. Here, we demonstrate that the phosphorylation of EZH2 by cyclin-dependent kinases at Thr416 creates a docking site for the ForkHead-associated domain of NIPP1. Recruited NIPP1 enables the net phosphorylation of EZH2 by inhibiting its dephosphorylation by PP1. Accordingly, a NIPP1-binding mutant of EZH2 is hypophosphorylated, and the knockdown of NIPP1 results in a reduced phosphorylation of endogenous EZH2. Conversely, the loss of PP1 is associated with a hyperphosphorylation of EZH2. A genome-wide promoter-binding profiling in HeLa cells revealed that the NIPP1-binding mutant shows a deficient association with about a third of the Polycomb target genes, and these are enriched for functions in proliferation. Our data identify PP1 as an EZH2 phosphatase and demonstrate that the phosphorylation-regulated association of EZH2 with proliferation-related targets depends on associated NIPP1.
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Affiliation(s)
- Nikki Minnebo
- Laboratory of Biosignaling & Therapeutics, Department of Cellular and Molecular Medicine, KU Leuven, B-3000 Leuven, Belgium
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Breuer D, Kotelkin A, Ammosova T, Kumari N, Ivanov A, Ilatovskiy AV, Beullens M, Roane PR, Bollen M, Petukhov MG, Kashanchi F, Nekhai S. CDK2 regulates HIV-1 transcription by phosphorylation of CDK9 on serine 90. Retrovirology 2012; 9:94. [PMID: 23140174 PMCID: PMC3515335 DOI: 10.1186/1742-4690-9-94] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Accepted: 10/26/2012] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND HIV-1 transcription is activated by the viral Tat protein that recruits host positive transcription elongation factor-b (P-TEFb) containing CDK9/cyclin T1 to the HIV-1 promoter. P-TEFb in the cells exists as a lower molecular weight CDK9/cyclin T1 dimer and a high molecular weight complex of 7SK RNA, CDK9/cyclin T1, HEXIM1 dimer and several additional proteins. Our previous studies implicated CDK2 in HIV-1 transcription regulation. We also found that inhibition of CDK2 by iron chelators leads to the inhibition of CDK9 activity, suggesting a functional link between CDK2 and CDK9. Here, we investigate whether CDK2 phosphorylates CDK9 and regulates its activity. RESULTS The siRNA-mediated knockdown of CDK2 inhibited CDK9 kinase activity and reduced CDK9 phosphorylation. Stable shRNA-mediated CDK2 knockdown inhibited HIV-1 transcription, but also increased the overall level of 7SK RNA. CDK9 contains a motif (90SPYNR94) that is consensus CDK2 phosphorylation site. CDK9 was phosphorylated on Ser90 by CDK2 in vitro. In cultured cells, CDK9 phosphorylation was reduced when Ser90 was mutated to an Ala. Phosphorylation of CDK9 on Ser90 was also detected with phospho-specific antibodies and it was reduced after the knockdown of CDK2. CDK9 expression decreased in the large complex for the CDK9-S90A mutant and was correlated with a reduced activity and an inhibition of HIV-1 transcription. In contrast, the CDK9-S90D mutant showed a slight decrease in CDK9 expression in both the large and small complexes but induced Tat-dependent HIV-1 transcription. Molecular modeling showed that Ser 90 of CDK9 is located on a flexible loop exposed to solvent, suggesting its availability for phosphorylation. CONCLUSION Our data indicate that CDK2 phosphorylates CDK9 on Ser 90 and thereby contributes to HIV-1 transcription. The phosphorylation of Ser90 by CDK2 represents a novel mechanism of HIV-1 regulated transcription and provides a new strategy for activation of latent HIV-1 provirus.
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Affiliation(s)
- Denitra Breuer
- Center for Sickle Cell Disease, Department of Medicine, Howard University, 1840 7th Street, N.W. HURB1, Suite 202, Washington, DC 20001, USA
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O'Connell N, Nichols SR, Heroes E, Beullens M, Bollen M, Peti W, Page R. The molecular basis for substrate specificity of the nuclear NIPP1:PP1 holoenzyme. Structure 2012; 20:1746-56. [PMID: 22940584 PMCID: PMC3472097 DOI: 10.1016/j.str.2012.08.003] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 08/06/2012] [Accepted: 08/07/2012] [Indexed: 11/18/2022]
Abstract
Regulation of protein phosphatase 1 (PP1) is controlled by a diverse array of regulatory proteins. However, how these proteins direct PP1 specificity is not well understood. More than one-third of the nuclear pool of PP1 forms a holoenzyme with the nuclear inhibitor of PP1, NIPP1, to regulate chromatin remodeling, among other essential biological functions. Here, we show that the PP1-binding domain of NIPP1 is an intrinsically disordered protein, which binds PP1 in an unexpected manner. NIPP1 forms an α helix that engages PP1 at a unique interaction site, using polar rather than hydrophobic contacts. Importantly, the structure also reveals a shared PP1 interaction site outside of the RVxF motif, the ΦΦ motif. Finally, we show that NIPP1:PP1 substrate selectivity is determined by altered electrostatics and enhanced substrate localization. Together, our results provide the molecular basis by which NIPP1 directs PP1 substrate specificity in the nucleus.
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Affiliation(s)
- Nichole O'Connell
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, Providence, RI 02912, USA
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Jansen S, Perrakis A, Ulens C, Winkler C, Andries M, Joosten RP, Van Acker M, Luyten FP, Moolenaar WH, Bollen M. Structure of NPP1, an ectonucleotide pyrophosphatase/phosphodiesterase involved in tissue calcification. Structure 2012; 20:1948-59. [PMID: 23041369 DOI: 10.1016/j.str.2012.09.001] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 08/25/2012] [Accepted: 09/02/2012] [Indexed: 10/27/2022]
Abstract
Ectonucleotide pyrophosphatase/phosphodiesterase-1 (NPP1) converts extracellular nucleotides into inorganic pyrophosphate, whereas its close relative NPP2/autotaxin hydrolyzes lysophospholipids. NPP1 regulates calcification in mineralization-competent tissues, and a lack of NPP1 function underlies calcification disorders. Here, we show that NPP1 forms homodimers via intramembrane disulfide bonding, but is also processed intracellularly to a secreted monomer. The structure of secreted NPP1 reveals a characteristic bimetallic active site and a nucleotide-binding groove, but it lacks the lipid-binding pocket and open tunnel present in NPP2. A loop adjacent to the nucleotide-binding site, which is disordered in NPP2, is well ordered in NPP1 and might promote nucleotide binding. Remarkably, the N-terminal somatomedin B-like domains of NPP1, unlike those in NPP2, are flexible and do not contact the catalytic domain. Our results provide a structural basis for the nucleotide pyrophosphatase activity of NPP1 and help to understand how disease-causing mutations may affect NPP1 structure and function.
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Affiliation(s)
- Silvia Jansen
- Laboratory of Biosignaling and Therapeutics, Department of Cellular and Molecular Medicine, University of Leuven, 3000 Leuven, Belgium
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50
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Chatterjee J, Beullens M, Sukackaite R, Qian J, Lesage B, Hart DJ, Bollen M, Köhn M. Development of a peptide that selectively activates protein phosphatase-1 in living cells. Angew Chem Int Ed Engl 2012; 51:10054-9. [PMID: 22962028 PMCID: PMC3531619 DOI: 10.1002/anie.201204308] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2012] [Indexed: 11/29/2022]
Abstract
The first cell-penetrating peptide that activates protein phosphatase-1 (PP1) by disrupting a subset of PP1 complexes in living cells has been developed. Activated PP1 rapidly dephosphorylates its substrates, counteracting kinase activity inside cells. Activation of PP1 can thus be a novel approach to study PP1 function and to counteract Ser/Thr kinase activity under pathologically increased kinase signaling.
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Affiliation(s)
| | - Monique Beullens
- Laboratory of Biosignaling & Therapeutics, Katholieke Universiteit LeuvenLeuven (Belgium)
| | - Rasa Sukackaite
- EMBL Grenoble Outstation and Unit of Virus Host-Cell InteractionsUMI3265 UFJ-EMBL-CNRS, Grenoble (France)
| | - Junbin Qian
- Laboratory of Biosignaling & Therapeutics, Katholieke Universiteit LeuvenLeuven (Belgium)
| | - Bart Lesage
- Laboratory of Biosignaling & Therapeutics, Katholieke Universiteit LeuvenLeuven (Belgium)
| | - Darren J Hart
- EMBL Grenoble Outstation and Unit of Virus Host-Cell InteractionsUMI3265 UFJ-EMBL-CNRS, Grenoble (France)
| | | | - Maja Köhn
- Genome Biology UnitEMBL, Meyerhofstrasse 1, 69117 Heidelberg (Germany)
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