1
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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; 291:2615-2635. [PMID: 38303113 DOI: 10.1111/febs.17064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 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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2
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Fatalska A, Hodgson G, Freund SMV, Maslen SL, Morgan T, Thorkelsson SR, van Slegtenhorst M, Lorenz S, Andreeva A, Kaat LD, Bertolotti A. Recruitment of trimeric eIF2 by phosphatase non-catalytic subunit PPP1R15B. Mol Cell 2024; 84:506-521.e11. [PMID: 38159565 PMCID: PMC7615683 DOI: 10.1016/j.molcel.2023.12.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 09/06/2023] [Accepted: 12/08/2023] [Indexed: 01/03/2024]
Abstract
Regulated protein phosphorylation controls most cellular processes. The protein phosphatase PP1 is the catalytic subunit of many holoenzymes that dephosphorylate serine/threonine residues. How these enzymes recruit their substrates is largely unknown. Here, we integrated diverse approaches to elucidate how the PP1 non-catalytic subunit PPP1R15B (R15B) captures its full trimeric eIF2 substrate. We found that the substrate-recruitment module of R15B is largely disordered with three short helical elements, H1, H2, and H3. H1 and H2 form a clamp that grasps the substrate in a region remote from the phosphorylated residue. A homozygous N423D variant, adjacent to H1, reducing substrate binding and dephosphorylation was discovered in a rare syndrome with microcephaly, developmental delay, and intellectual disability. These findings explain how R15B captures its 125 kDa substrate by binding the far end of the complex relative to the phosphosite to present it for dephosphorylation by PP1, a paradigm of broad relevance.
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Affiliation(s)
- Agnieszka Fatalska
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - George Hodgson
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - Stefan M V Freund
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - Sarah L Maslen
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - Tomos Morgan
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - Sigurdur R Thorkelsson
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - Marjon van Slegtenhorst
- Department of Clinical Genetics, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Sonja Lorenz
- Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany
| | - Antonina Andreeva
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - Laura Donker Kaat
- Department of Clinical Genetics, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Anne Bertolotti
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom.
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3
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Choy MS, Srivastava G, Robinson LC, Tatchell K, Page R, Peti W. The SDS22:PP1:I3 complex: SDS22 binding to PP1 loosens the active site metal to prime metal exchange. J Biol Chem 2024; 300:105515. [PMID: 38042495 PMCID: PMC10776994 DOI: 10.1016/j.jbc.2023.105515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 11/20/2023] [Accepted: 11/22/2023] [Indexed: 12/04/2023] Open
Abstract
SDS22 and Inhibitor-3 (I3) are two ancient regulators of protein phosphatase 1 (PP1) that regulate multiple essential biological processes. Both SDS22 and I3 form stable dimeric complexes with PP1; however, and atypically for PP1 regulators, they also form a triple complex, where both proteins bind to PP1 simultaneously (SPI complex). Here we report the crystal structure of the SPI complex. While both regulators bind PP1 in conformations identical to those observed in their individual PP1 complexes, PP1 adopts the SDS22-bound conformation, which lacks its M1 metal. Unexpectedly, surface plasmon resonance (SPR) revealed that the affinity of I3 for the SDS22:PP1 complex is ∼10-fold lower than PP1 alone. We show that this change in binding affinity is solely due to the interaction of I3 with the PP1 active site, specifically PP1's M2 metal, demonstrating that SDS22 likely allows for PP1 M2 metal exchange and thus PP1 biogenesis.
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Affiliation(s)
- Meng S Choy
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Gautam Srivastava
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Lucy C Robinson
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA
| | - Kelly Tatchell
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA
| | - Rebecca Page
- Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut, USA.
| | - Wolfgang Peti
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, Connecticut, USA.
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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: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [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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Alba-Posse EJ, Bruque CD, Gándola Y, Gasulla J, Nadra AD. From in-silico screening to in-vitro evaluation: Enhancing the detection of Microcystins with engineered PP1 mutant variants. J Struct Biol 2023; 215:108043. [PMID: 37935286 DOI: 10.1016/j.jsb.2023.108043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Revised: 10/20/2023] [Accepted: 11/04/2023] [Indexed: 11/09/2023]
Abstract
Cyanotoxins produced during harmful algal blooms (CyanoHABs) have become a worldwide issue of concern. Microcystins (MC) are the most ubiquitous group of cyanotoxins and have known carcinogenic and hepatotoxic effects. The protein phosphatase inhibition assays (PPIAs), based on the inhibition of Protein Phosphatase 1/2A (PP1/PP2A) by MC, are one of the most cost-effective options for detecting MC. In this work, we aimed to design in-silico and evaluate in-vitro mutant variants of the PP1 protein, in order to enhance their capabilities as a MC biosensor. To this end, we performed an in-silico active site-saturated mutagenesis screening, followed by stability and docking affinity calculation with the MCLR cyanotoxin. Candidates with improved both affinity and stability were further tested in a fully flexible active-site docking. The best-scored mutations (19) were individually analysed regarding their locations and interactions. Four of them (p.D197F; p.Q249Y; p.S129W; p.D220Q) were selected for in-vitro expression and evaluation. Mutant p.D197F, exhibited a significant increment in inhibition by MCLR with respect to the WT, while showing a non-significant difference in stability nor activity. This successful PP1 inhibition enhancement suggests the potential of the p.D197F variant for practical MC detection applications.
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Affiliation(s)
- Ezequiel J Alba-Posse
- Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología y Biología Molecular y Celular, Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Universidad de Buenos Aires, Intendente Güiraldes 2160, C1428EGA Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290, C1425FQB Buenos Aires, Argentina
| | - Carlos David Bruque
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290, C1425FQB Buenos Aires, Argentina; Unidad de Conocimiento Traslacional Hospitalaria Patagónica, Hospital de Alta Complejidad El Calafate - S.A.M.I.C., Jorge Newbery 453, CP9405 El Calafate, Santa Cruz, Argentina
| | - Yamila Gándola
- Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología y Biología Molecular y Celular, Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Universidad de Buenos Aires, Intendente Güiraldes 2160, C1428EGA Buenos Aires, Argentina
| | - Javier Gasulla
- Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología y Biología Molecular y Celular, Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Universidad de Buenos Aires, Intendente Güiraldes 2160, C1428EGA Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290, C1425FQB Buenos Aires, Argentina.
| | - Alejandro D Nadra
- Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología y Biología Molecular y Celular, Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Universidad de Buenos Aires, Intendente Güiraldes 2160, C1428EGA Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290, C1425FQB Buenos Aires, Argentina.
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6
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Bonsor DA, Simanshu DK. Structural insights into the role of SHOC2-MRAS-PP1C complex in RAF activation. FEBS J 2023; 290:4852-4863. [PMID: 37074066 PMCID: PMC10584989 DOI: 10.1111/febs.16800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 04/07/2023] [Accepted: 04/18/2023] [Indexed: 04/20/2023]
Abstract
RAF activation is a key step for signalling through the mitogen-activated protein kinase (MAPK) pathway. The SHOC2 protein, along with MRAS and PP1C, forms a high affinity, heterotrimeric holoenzyme that activates RAF kinases by dephosphorylating a specific phosphoserine. Recently, our research, along with that of three other teams, has uncovered valuable structural and functional insights into the SHOC2-MRAS-PP1C (SMP) holoenzyme complex. In this structural snapshot, we review SMP complex assembly, the dependency on the bound-nucleotide state of MRAS, the substitution of MRAS by the canonical RAS proteins and the roles of SHOC2 and MRAS on PP1C activity and specificity. Furthermore, we discuss the effect of several RASopathy mutations identified within the SMP complex and explore potential therapeutic approaches for targeting the SMP complex in RAS/RAF-driven cancers and RASopathies.
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Affiliation(s)
- Daniel A. Bonsor
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Dhirendra K. Simanshu
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
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7
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Nguyen H, Kettenbach AN. Substrate and phosphorylation site selection by phosphoprotein phosphatases. Trends Biochem Sci 2023; 48:713-725. [PMID: 37173206 PMCID: PMC10523993 DOI: 10.1016/j.tibs.2023.04.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 04/11/2023] [Accepted: 04/13/2023] [Indexed: 05/15/2023]
Abstract
Dynamic protein phosphorylation and dephosphorylation are essential regulatory mechanisms that ensure proper cellular signaling and biological functions. Deregulation of either reaction has been implicated in several human diseases. Here, we focus on the mechanisms that govern the specificity of the dephosphorylation reaction. Most cellular serine/threonine dephosphorylation is catalyzed by 13 highly conserved phosphoprotein phosphatase (PPP) catalytic subunits, which form hundreds of holoenzymes by binding to regulatory and scaffolding subunits. PPP holoenzymes recognize phosphorylation site consensus motifs and interact with short linear motifs (SLiMs) or structural elements distal to the phosphorylation site. We review recent advances in understanding the mechanisms of PPP site-specific dephosphorylation preference and substrate recruitment and highlight examples of their interplay in the regulation of cell division.
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Affiliation(s)
- Hieu Nguyen
- Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth College, Hanover, NH 03755, USA
| | - Arminja N Kettenbach
- Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth College, Hanover, NH 03755, USA; Dartmouth Cancer Center, Lebanon, NH 03756, USA.
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8
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Wang Q. The role of forkhead-associated (FHA)-domain proteins in plant biology. PLANT MOLECULAR BIOLOGY 2023; 111:455-472. [PMID: 36849846 DOI: 10.1007/s11103-023-01338-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 01/31/2023] [Indexed: 06/18/2023]
Abstract
The forkhead-associated (FHA) domain, a well-characterized small protein module that mediates protein-protein interactions by targeting motifs containing phosphothreonine, is present in many regulatory molecules like protein kinase, phosphatases, transcription factors, and other functional proteins. FHA-domain containing proteins in yeast and human are involved in a large variety of cellular processes such as DNA repair, cell cycle arrest, or pre-mRNA processing. Since the first FHA-domain protein, kinase-associated protein phosphatase (KAPP) was found in plants, the interest in plant FHA-containing proteins has increased dramatically, mainly due to the important role of FHA domain-containing proteins in plant growth and development. In this review, we provide a comprehensive overview of the fundamental properties of FHA domain-containing proteins in plants, and systematically summarized and analyzed the research progress of proteins containing the FHA domain in plants. We also emphasized that AT5G47790 and its homologs may play an important role as the regulatory subunit of protein phosphatase 1 (PP1) in plants.
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Affiliation(s)
- Qiuling Wang
- Institute of Future Agriculture, State Key Laboratory of Crop Stress Biology for Arid Areas, State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, 712100, Shaanxi, People's Republic of China.
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, 730000, People's Republic of China.
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9
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Alba Posse EJ, González C, Carriquiriborde P, Nadra A, Gasulla J. Optimization and validation of a protein phosphatase inhibition assay for accessible microcystin detection. Talanta 2023; 255:124174. [PMID: 36608426 DOI: 10.1016/j.talanta.2022.124174] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 11/28/2022] [Accepted: 12/04/2022] [Indexed: 12/27/2022]
Abstract
The presence of cyanobacterial toxins in freshwater constitutes an increasing public health concern, especially affecting developing countries where the high cost of available methods makes monitoring programs difficult. The phosphatase inhibition assay (PPIA) is a sensitive method with low instrument requirements that allows the quantification of the most frequent cyanotoxins, microcystins (MCs). In this work, we implemented a PPIA, starting from Protein Phosphatase 1 (PP1) expression up to the validation with samples of algal blooms from Argentina. To do this, we optimized the expression and lyophilization of PP1, and the assay conditions. Also, we included robustness and possible interference analysis. We evaluated the most widely used cyanobacterial lysis methods and determined that heating for 15 min at 95 °C is simple and adequate for this assay. Then, we performed MC spikes recovery assays on water samples from three dams from Argentina, resulting in a recovery ranging from 77 to 115%. The limit of detection (LOD) was 0.4 μg/L and the linear range is 0.4 μg/L - 5 μg/L. Finally, we evaluated 65 environmental samples where MCs was measured by ELISA test containing from 0 μg/L to 625 μg/L. The PPIA showed excellent correlation (Pearson correlation coefficient = 0.967), no false negative and no false positives above the 1 μg/L WHO guideline (0.11 false positive rate). In conclusion, we optimized and validated a PPIA to be an effective and accessible alternative to available commercial tests.
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Affiliation(s)
- Ezequiel Jorge Alba Posse
- Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología y Biología Molecular y Celular, Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Universidad de Buenos Aires, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290, C1425FQB Buenos Aires, Argentina
| | - Carolina González
- Facultad de Ciencias Exactas y Naturales, Departamento de Ecología, Genética y Evolución, Instituto IEGEBA (CONICET-UBA), Universidad de Buenos Aires, Argentina; Centro de investigaciones, Agua y Saneamientos Argentinos, CABA, Argentina
| | - Pedro Carriquiriborde
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290, C1425FQB Buenos Aires, Argentina; Centro de Investigaciones Del Medio Ambiente (CIM),Universidad Nacional de la Plata-CONICET, La Plata, Argentina
| | - Alejandro Nadra
- Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología y Biología Molecular y Celular, Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Universidad de Buenos Aires, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290, C1425FQB Buenos Aires, Argentina
| | - Javier Gasulla
- Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología y Biología Molecular y Celular, Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Universidad de Buenos Aires, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290, C1425FQB Buenos Aires, Argentina; Centro de Investigaciones Del Medio Ambiente (CIM),Universidad Nacional de la Plata-CONICET, La Plata, Argentina.
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10
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Srivastava G, Choy MS, Bolik-Coulon N, Page R, Peti W. Inhibitor-3 inhibits Protein Phosphatase 1 via a metal binding dynamic protein-protein interaction. Nat Commun 2023; 14:1798. [PMID: 37002212 PMCID: PMC10066265 DOI: 10.1038/s41467-023-37372-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 02/21/2023] [Indexed: 04/03/2023] Open
Abstract
To achieve substrate specificity, protein phosphate 1 (PP1) forms holoenzymes with hundreds of regulatory and inhibitory proteins. Inhibitor-3 (I3) is an ancient inhibitor of PP1 with putative roles in PP1 maturation and the regulation of PP1 activity. Here, we show that I3 residues 27-68 are necessary and sufficient for PP1 binding and inhibition. In addition to a canonical RVxF motif, which is shared by nearly all PP1 regulators and inhibitors, and a non-canonical SILK motif, I3 also binds PP1 via multiple basic residues that bind directly in the PP1 acidic substrate binding groove, an interaction that provides a blueprint for how substrates bind this groove for dephosphorylation. Unexpectedly, this interaction positions a CCC (cys-cys-cys) motif to bind directly across the PP1 active site. Using biophysical and inhibition assays, we show that the I3 CCC motif binds and inhibits PP1 in an unexpected dynamic, fuzzy manner, via transient engagement of the PP1 active site metals. Together, these data not only provide fundamental insights into the mechanisms by which IDP protein regulators of PP1 achieve inhibition, but also shows that fuzzy interactions between IDPs and their folded binding partners, in addition to enhancing binding affinity, can also directly regulate enzyme activity.
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Affiliation(s)
- Gautam Srivastava
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT, USA
| | - Meng S Choy
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT, USA
| | - Nicolas Bolik-Coulon
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA
| | - Rebecca Page
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT, USA
| | - Wolfgang Peti
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT, USA.
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11
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The ribosomal RNA processing 1B:protein phosphatase 1 holoenzyme reveals non-canonical PP1 interaction motifs. Cell Rep 2022; 41:111726. [PMID: 36450254 PMCID: PMC9813921 DOI: 10.1016/j.celrep.2022.111726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 09/20/2022] [Accepted: 11/03/2022] [Indexed: 12/03/2022] Open
Abstract
The serine/threonine protein phosphatase 1 (PP1) dephosphorylates hundreds of substrates by associating with >200 regulatory proteins to form specific holoenzymes. The major PP1 targeting protein in the nucleolus is RRP1B (ribosomal RNA processing 1B). In addition to selectively recruiting PP1β/PP1γ to the nucleolus, RRP1B also has a key role in ribosome biogenesis, among other functions. How RRP1B binds PP1 and regulates nucleolar phosphorylation signaling is not yet known. Here, we show that RRP1B recruits PP1 via established (RVxF/SILK/ΦΦ) and non-canonical motifs. These atypical interaction sites, the PP1β/γ specificity, and N-terminal AF-binding pockets rely on hydrophobic interactions that contribute to binding and, via phosphorylation, regulate complex formation. This work advances our understanding of PP1 isoform selectivity, reveals key roles of N-terminal PP1 residues in regulator binding, and suggests that additional PP1 interaction sites have yet to be identified, all of which are necessary for a systems biology understanding of PP1 function.
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12
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Bonsor DA, Alexander P, Snead K, Hartig N, Drew M, Messing S, Finci LI, Nissley DV, McCormick F, Esposito D, Rodriguez-Viciana P, Stephen AG, Simanshu DK. Structure of the SHOC2-MRAS-PP1C complex provides insights into RAF activation and Noonan syndrome. Nat Struct Mol Biol 2022; 29:966-977. [PMID: 36175670 PMCID: PMC10365013 DOI: 10.1038/s41594-022-00841-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 08/12/2022] [Indexed: 11/08/2022]
Abstract
SHOC2 acts as a strong synthetic lethal interactor with MEK inhibitors in multiple KRAS cancer cell lines. SHOC2 forms a heterotrimeric complex with MRAS and PP1C that is essential for regulating RAF and MAPK-pathway activation by dephosphorylating a specific phosphoserine on RAF kinases. Here we present the high-resolution crystal structure of the SHOC2-MRAS-PP1C (SMP) complex and apo-SHOC2. Our structures reveal that SHOC2, MRAS, and PP1C form a stable ternary complex in which all three proteins synergistically interact with each other. Our results show that dephosphorylation of RAF substrates by PP1C is enhanced upon interacting with SHOC2 and MRAS. The SMP complex forms only when MRAS is in an active state and is dependent on SHOC2 functioning as a scaffolding protein in the complex by bringing PP1C and MRAS together. Our results provide structural insights into the role of the SMP complex in RAF activation and how mutations found in Noonan syndrome enhance complex formation, and reveal new avenues for therapeutic interventions.
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Affiliation(s)
- Daniel A Bonsor
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Patrick Alexander
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Kelly Snead
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Nicole Hartig
- UCL Cancer Institute, University College London, London, UK
| | - Matthew Drew
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Simon Messing
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Lorenzo I Finci
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Dwight V Nissley
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Frank McCormick
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
- University of California, San Francisco Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA
| | - Dominic Esposito
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | | | - Andrew G Stephen
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Dhirendra K Simanshu
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA.
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13
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Hauseman ZJ, Fodor M, Dhembi A, Viscomi J, Egli D, Bleu M, Katz S, Park E, Jang DM, Porter KA, Meili F, Guo H, Kerr G, Mollé S, Velez-Vega C, Beyer KS, Galli GG, Maira SM, Stams T, Clark K, Eck MJ, Tordella L, Thoma CR, King DA. Structure of the MRAS-SHOC2-PP1C phosphatase complex. Nature 2022; 609:416-423. [PMID: 35830882 PMCID: PMC9452295 DOI: 10.1038/s41586-022-05086-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 07/07/2022] [Indexed: 11/09/2022]
Abstract
RAS-MAPK signalling is fundamental for cell proliferation and is altered in most human cancers1-3. However, our mechanistic understanding of how RAS signals through RAF is still incomplete. Although studies revealed snapshots for autoinhibited and active RAF-MEK1-14-3-3 complexes4, the intermediate steps that lead to RAF activation remain unclear. The MRAS-SHOC2-PP1C holophosphatase dephosphorylates RAF at serine 259, resulting in the partial displacement of 14-3-3 and RAF-RAS association3,5,6. MRAS, SHOC2 and PP1C are mutated in rasopathies-developmental syndromes caused by aberrant MAPK pathway activation6-14-and SHOC2 itself has emerged as potential target in receptor tyrosine kinase (RTK)-RAS-driven tumours15-18. Despite its importance, structural understanding of the SHOC2 holophosphatase is lacking. Here we determine, using X-ray crystallography, the structure of the MRAS-SHOC2-PP1C complex. SHOC2 bridges PP1C and MRAS through its concave surface and enables reciprocal interactions between all three subunits. Biophysical characterization indicates a cooperative assembly driven by the MRAS GTP-bound active state, an observation that is extendible to other RAS isoforms. Our findings support the concept of a RAS-driven and multi-molecular model for RAF activation in which individual RAS-GTP molecules recruit RAF-14-3-3 and SHOC2-PP1C to produce downstream pathway activation. Importantly, we find that rasopathy and cancer mutations reside at protein-protein interfaces within the holophosphatase, resulting in enhanced affinities and function. Collectively, our findings shed light on a fundamental mechanism of RAS biology and on mechanisms of clinically observed enhanced RAS-MAPK signalling, therefore providing the structural basis for therapeutic interventions.
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Affiliation(s)
| | - Michelle Fodor
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Anxhela Dhembi
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Jessica Viscomi
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - David Egli
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Melusine Bleu
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Stephanie Katz
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Eunyoung Park
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Dong Man Jang
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | | | - Fabian Meili
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Hongqiu Guo
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Grainne Kerr
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Sandra Mollé
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | | | - Kim S Beyer
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Giorgio G Galli
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | | | - Travis Stams
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Kirk Clark
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Michael J Eck
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Luca Tordella
- Novartis Institutes for BioMedical Research, Basel, Switzerland.
| | - Claudio R Thoma
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA.
| | - Daniel A King
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA.
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14
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Fontanillo M, Trebacz M, Reinkemeier CD, Avilés Huerta D, Uhrig U, Sehr P, Köhn M. Short peptide pharmacophores developed from protein phosphatase-1 disrupting peptides (PDPs). Bioorg Med Chem 2022; 65:116785. [PMID: 35525109 PMCID: PMC7613447 DOI: 10.1016/j.bmc.2022.116785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 04/27/2022] [Accepted: 04/27/2022] [Indexed: 11/28/2022]
Abstract
PP1 is a major phosphoserine/threonine-specific phosphatase that is involved in diseases such as heart insufficiency and diabetes. PP1-disrupting peptides (PDPs) are selective modulators of PP1 activity that release its catalytic subunit, which then dephosphorylates nearby substrates. Recently, PDPs enabled the creation of phosphatase-recruiting chimeras, which are bifunctional molecules that guide PP1 to a kinase to dephosphorylate and inactivate it. However, PDPs are 23mer peptides, which is not optimal for their use in therapy due to potential stability and immunogenicity issues. Therefore, we present here the sequence optimization of the 23mer PDP to a 5mer peptide, involving several attempts considering structure-based virtual screening, high throughput screening and peptide sequence optimization. We provide here a strong pharmacophore as lead structure to enable PP1 targeting in therapy or its use in phosphatase-recruiting chimeras in the future.
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Affiliation(s)
| | - Malgorzata Trebacz
- Centres for Biological Signalling Studies BIOSS and CIBSS, University of Freiburg, Freiburg, Germany; Faculty of Biology, University of Freiburg, Schänzlestrasse 18, 79104 Freiburg, Germany
| | | | | | - Ulrike Uhrig
- Chemical Biology Core Facility, EMBL, Heidelberg, Germany
| | - Peter Sehr
- Chemical Biology Core Facility, EMBL, Heidelberg, Germany
| | - Maja Köhn
- Genome Biology Unit, EMBL, Heidelberg, Germany; Centres for Biological Signalling Studies BIOSS and CIBSS, University of Freiburg, Freiburg, Germany; Faculty of Biology, University of Freiburg, Schänzlestrasse 18, 79104 Freiburg, Germany.
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15
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Kliche J, Ivarsson Y. Orchestrating serine/threonine phosphorylation and elucidating downstream effects by short linear motifs. Biochem J 2022; 479:1-22. [PMID: 34989786 PMCID: PMC8786283 DOI: 10.1042/bcj20200714] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 12/16/2021] [Accepted: 12/20/2021] [Indexed: 12/13/2022]
Abstract
Cellular function is based on protein-protein interactions. A large proportion of these interactions involves the binding of short linear motifs (SLiMs) by folded globular domains. These interactions are regulated by post-translational modifications, such as phosphorylation, that create and break motif binding sites or tune the affinity of the interactions. In addition, motif-based interactions are involved in targeting serine/threonine kinases and phosphatases to their substrate and contribute to the specificity of the enzymatic actions regulating which sites are phosphorylated. Here, we review how SLiM-based interactions assist in determining the specificity of serine/threonine kinases and phosphatases, and how phosphorylation, in turn, affects motif-based interactions. We provide examples of SLiM-based interactions that are turned on/off, or are tuned by serine/threonine phosphorylation and exemplify how this affects SLiM-based protein complex formation.
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Affiliation(s)
- Johanna Kliche
- Department of Chemistry – BMC, Uppsala University, Husargatan 3, Box 576 751 23 Uppsala, Sweden
| | - Ylva Ivarsson
- Department of Chemistry – BMC, Uppsala University, Husargatan 3, Box 576 751 23 Uppsala, Sweden
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16
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Fujimitsu K, Yamano H. Dynamic regulation of mitotic ubiquitin ligase APC/C by coordinated Plx1 kinase and PP2A phosphatase action on a flexible Apc1 loop. EMBO J 2021; 40:e107516. [PMID: 34291488 PMCID: PMC8441438 DOI: 10.15252/embj.2020107516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 07/02/2021] [Accepted: 07/06/2021] [Indexed: 11/29/2022] Open
Abstract
The anaphase-promoting complex/cyclosome (APC/C), a multi-subunit ubiquitin ligase essential for cell cycle control, is regulated by reversible phosphorylation. APC/C phosphorylation by cyclin-dependent kinase 1 (Cdk1) promotes Cdc20 co-activator loading in mitosis to form active APC/C-Cdc20. However, detailed phospho-regulation of APC/C dynamics through other kinases and phosphatases is still poorly understood. Here, we show that an interplay between polo-like kinase (Plx1) and PP2A-B56 phosphatase on a flexible loop domain of the subunit Apc1 (Apc1-loop500 ) controls APC/C activity and mitotic progression. Plx1 directly binds to the Apc1-loop500 in a phosphorylation-dependent manner and promotes the formation of APC/C-Cdc20 via Apc3 phosphorylation. Upon phosphorylation of loop residue T532, PP2A-B56 is recruited to the Apc1-loop500 and differentially promotes dissociation of Plx1 and PP2A-B56 through dephosphorylation of Plx1-binding sites. Stable Plx1 binding, which prevents PP2A-B56 recruitment, prematurely activates the APC/C and delays APC/C dephosphorylation during mitotic exit. Furthermore, the phosphorylation status of the Apc1-loop500 is controlled by distant Apc3-loop phosphorylation. Our study suggests that phosphorylation-dependent feedback regulation through flexible loop domains within a macromolecular complex coordinates the activity and dynamics of the APC/C during the cell cycle.
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Affiliation(s)
- Kazuyuki Fujimitsu
- Cell Cycle Control GroupUCL Cancer InstituteUniversity College LondonLondonUK
| | - Hiroyuki Yamano
- Cell Cycle Control GroupUCL Cancer InstituteUniversity College LondonLondonUK
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17
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Swartz SZ, Nguyen HT, McEwan BC, Adamo ME, Cheeseman IM, Kettenbach AN. Selective dephosphorylation by PP2A-B55 directs the meiosis I-meiosis II transition in oocytes. eLife 2021; 10:70588. [PMID: 34342579 PMCID: PMC8370769 DOI: 10.7554/elife.70588] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Accepted: 08/02/2021] [Indexed: 12/17/2022] Open
Abstract
Meiosis is a specialized cell cycle that requires sequential changes to the cell division machinery to facilitate changing functions. To define the mechanisms that enable the oocyte-to-embryo transition, we performed time-course proteomics in synchronized sea star oocytes from prophase I through the first embryonic cleavage. Although we found that protein levels were broadly stable, our analysis reveals that dynamic waves of phosphorylation underlie each meiotic stage. We found that the phosphatase PP2A-B55 is reactivated at the meiosis I/meiosis II (MI/MII) transition, resulting in the preferential dephosphorylation of threonine residues. Selective dephosphorylation is critical for directing the MI/MII transition as altering PP2A-B55 substrate preferences disrupts key cell cycle events after MI. In addition, threonine to serine substitution of a conserved phosphorylation site in the substrate INCENP prevents its relocalization at anaphase I. Thus, through its inherent phospho-threonine preference, PP2A-B55 imposes specific phosphoregulated behaviors that distinguish the two meiotic divisions.
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Affiliation(s)
- S Zachary Swartz
- Whitehead Institute for Biomedical Research, Cambridge, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, United States
| | - Hieu T Nguyen
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, United States
| | - Brennan C McEwan
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, United States
| | - Mark E Adamo
- Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, United States
| | - Iain M Cheeseman
- Whitehead Institute for Biomedical Research, Cambridge, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, United States
| | - Arminja N Kettenbach
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, United States.,Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, United States
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18
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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] [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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19
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Fedoryshchak RO, Přechová M, Butler AM, Lee R, O'Reilly N, Flynn HR, Snijders AP, Eder N, Ultanir S, Mouilleron S, Treisman R. Molecular basis for substrate specificity of the Phactr1/PP1 phosphatase holoenzyme. eLife 2020; 9:61509. [PMID: 32975518 PMCID: PMC7599070 DOI: 10.7554/elife.61509] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 09/24/2020] [Indexed: 01/01/2023] Open
Abstract
PPP-family phosphatases such as PP1 have little intrinsic specificity. Cofactors can target PP1 to substrates or subcellular locations, but it remains unclear how they might confer sequence-specificity on PP1. The cytoskeletal regulator Phactr1 is a neuronally enriched PP1 cofactor that is controlled by G-actin. Structural analysis showed that Phactr1 binding remodels PP1's hydrophobic groove, creating a new composite surface adjacent to the catalytic site. Using phosphoproteomics, we identified mouse fibroblast and neuronal Phactr1/PP1 substrates, which include cytoskeletal components and regulators. We determined high-resolution structures of Phactr1/PP1 bound to the dephosphorylated forms of its substrates IRSp53 and spectrin αII. Inversion of the phosphate in these holoenzyme-product complexes supports the proposed PPP-family catalytic mechanism. Substrate sequences C-terminal to the dephosphorylation site make intimate contacts with the composite Phactr1/PP1 surface, which are required for efficient dephosphorylation. Sequence specificity explains why Phactr1/PP1 exhibits orders-of-magnitude enhanced reactivity towards its substrates, compared to apo-PP1 or other PP1 holoenzymes.
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Affiliation(s)
- Roman O Fedoryshchak
- Signalling and Transcription Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Magdalena Přechová
- Signalling and Transcription Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Abbey M Butler
- Signalling and Transcription Laboratory, The Francis Crick Institute, London, United Kingdom.,Structural Biology Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Rebecca Lee
- Signalling and Transcription Laboratory, The Francis Crick Institute, London, United Kingdom.,Structural Biology Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Nicola O'Reilly
- Peptide Chemistry Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Helen R Flynn
- Proteomics Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Ambrosius P Snijders
- Proteomics Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Noreen Eder
- Proteomics Science Technology Platform, The Francis Crick Institute, London, United Kingdom.,Kinases and Brain Development Laboratory The Francis Crick Institute, London, United Kingdom
| | - Sila Ultanir
- Kinases and Brain Development Laboratory The Francis Crick Institute, London, United Kingdom
| | - Stephane Mouilleron
- Structural Biology Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Richard Treisman
- Signalling and Transcription Laboratory, The Francis Crick Institute, London, United Kingdom
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20
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Casamayor A, Ariño J. Controlling Ser/Thr protein phosphatase PP1 activity and function through interaction with regulatory subunits. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2020; 122:231-288. [PMID: 32951813 DOI: 10.1016/bs.apcsb.2020.06.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Protein phosphatase 1 is a major Ser/Thr protein phosphatase activity in eukaryotic cells. It is composed of a catalytic polypeptide (PP1C), with little substrate specificity, that interacts with a large variety of proteins of diverse structure (regulatory subunits). The diversity of holoenzymes that can be formed explain the multiplicity of cellular functions under the control of this phosphatase. In quite a few cases, regulatory subunits have an inhibitory role, downregulating the activity of the phosphatase. In this chapter we shall introduce PP1C and review the most relevant families of PP1C regulatory subunits, with particular emphasis in describing the structural basis for their interaction.
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Affiliation(s)
- Antonio Casamayor
- Institut de Biotecnologia i Biomedicina & Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Cerdanyola, del Vallès, Spain
| | - Joaquín Ariño
- Institut de Biotecnologia i Biomedicina & Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Cerdanyola, del Vallès, Spain
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21
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Abstract
The metalloenzyme protein phosphatase 1 (PP1), which is responsible for ≥50% of all dephosphorylation reactions, is regulated by scores of regulatory proteins, including the highly conserved SDS22 protein. SDS22 has numerous diverse functions, surprisingly acting as both a PP1 inhibitor and as an activator. Here, we integrate cellular, biophysical, and crystallographic studies to address this conundrum. We discovered that SDS22 selectively binds a unique conformation of PP1 that contains a single metal (M2) at its active site, i.e., SDS22 traps metal-deficient inactive PP1. Furthermore, we showed that SDS22 dissociation is accompanied by a second metal (M1) being loaded into PP1, as free metal cannot dissociate the complex and M1-deficient mutants remain constitutively trapped by SDS22. Together, our findings reveal that M1 metal loading and loss are essential for PP1 regulation in cells, which has broad implications for PP1 maturation, activity, and holoenzyme subunit exchange.
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22
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Lin X, Ammosova T, Choy MS, Pietzsch CA, Ivanov A, Ahmad A, Saygideğer Y, Kumari N, Kovalskyy D, Üren A, Peti W, Bukreyev A, Nekhai S. Targeting the Non-catalytic RVxF Site of Protein Phosphatase-1 With Small Molecules for Ebola Virus Inhibition. Front Microbiol 2019; 10:2145. [PMID: 31572348 PMCID: PMC6753193 DOI: 10.3389/fmicb.2019.02145] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 08/30/2019] [Indexed: 12/17/2022] Open
Abstract
Ebola virus (EBOV) is a non-segmented negative-sense RNA virus that causes a severe human disease. The ongoing EBOV outbreak in the Eastern part of Democratic Republic of the Congo has resulted to date in over 2500 confirmed cases including over 1500 deaths. Difficulties with vaccine administration indicate the necessity for development of new general drugs and therapeutic strategies against EBOV. Host Ser/Thr protein phosphatases, particularly PP1 and PP2A, facilitate EBOV transcription by dephosphorylating the EBOV VP30 protein and switching activity of the polymerase complex toward replication. Previously, we developed small molecule 1E7-03 that targeted host protein phosphatase-1 (PP1) and induces phosphorylation of EBOV VP30 protein thus shifting transcription-replication balance and inhibiting EBOV replication. Here, we developed a new EBOV inhibitor, 1E7-07, that potently inhibits EBOV replication and displays significantly improved metabolic stability when compared to previously described 1E7-03. Proteome analysis of VP30 shows that 1E7-07 increases its phosphorylation on Thr-119 and Ser-124 over 3-fold with p < 0.001, which likely contributes to EBOV inhibition. We analyzed 1E7-07 binding to PP1 using a mass spectrometry-based protein painting approach. Combined with computational docking, protein painting shows that 1E7-07 binds to several PP1 sites including the RVxF site, C-terminal groove and NIPP1-helix binding pocket. Further analysis using surface plasmon resonance and a split NanoBiT system demonstrates that 1E7-07 binds primarily to the RVxF site. Together, detailed analysis of 1E7-07 binding to PP1 and identification of the RVxF site as the main binding site opens up an opportunity for future development of PP1-targeting EBOV inhibitors.
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Affiliation(s)
- Xionghao Lin
- Center for Sickle Cell Disease, College of Medicine, Howard University, Washington, DC, United States
- College of Dentistry, Howard University, Washington, DC, United States
| | - Tatiana Ammosova
- Center for Sickle Cell Disease, College of Medicine, Howard University, Washington, DC, United States
- Department of Medicine, College of Medicine, Howard University, Washington, DC, United States
- Yakut Science Centre of Complex Medical Problems, Yakutsk, Russia
| | - Meng S. Choy
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, United States
| | - Colette A. Pietzsch
- Department of Pathology, Department of Microbiology and Immunology, and Galveston National Laboratory, University of Texas Medical Branch at Galveston, Galveston, TX, United States
| | - Andrey Ivanov
- Center for Sickle Cell Disease, College of Medicine, Howard University, Washington, DC, United States
| | - Asrar Ahmad
- Center for Sickle Cell Disease, College of Medicine, Howard University, Washington, DC, United States
| | - Yasemin Saygideğer
- Georgetown Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, United States
| | - Namita Kumari
- Center for Sickle Cell Disease, College of Medicine, Howard University, Washington, DC, United States
| | - Dmytro Kovalskyy
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, TX, United States
| | - Aykut Üren
- Georgetown Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, United States
| | - Wolfgang Peti
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, United States
| | - Alexander Bukreyev
- Department of Pathology, Department of Microbiology and Immunology, and Galveston National Laboratory, University of Texas Medical Branch at Galveston, Galveston, TX, United States
| | - Sergei Nekhai
- Center for Sickle Cell Disease, College of Medicine, Howard University, Washington, DC, United States
- Department of Medicine, College of Medicine, Howard University, Washington, DC, United States
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23
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Brautigan DL, Shenolikar S. Protein Serine/Threonine Phosphatases: Keys to Unlocking Regulators and Substrates. Annu Rev Biochem 2019; 87:921-964. [PMID: 29925267 DOI: 10.1146/annurev-biochem-062917-012332] [Citation(s) in RCA: 110] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Protein serine/threonine phosphatases (PPPs) are ancient enzymes, with distinct types conserved across eukaryotic evolution. PPPs are segregated into types primarily on the basis of the unique interactions of PPP catalytic subunits with regulatory proteins. The resulting holoenzymes dock substrates distal to the active site to enhance specificity. This review focuses on the subunit and substrate interactions for PPP that depend on short linear motifs. Insights about these motifs from structures of holoenzymes open new opportunities for computational biology approaches to elucidate PPP networks. There is an expanding knowledge base of posttranslational modifications of PPP catalytic and regulatory subunits, as well as of their substrates, including phosphorylation, acetylation, and ubiquitination. Cross talk between these posttranslational modifications creates PPP-based signaling. Knowledge of PPP complexes, signaling clusters, as well as how PPPs communicate with each other in response to cellular signals should unlock the doors to PPP networks and signaling "clouds" that orchestrate and coordinate different aspects of cell physiology.
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Affiliation(s)
- David L Brautigan
- Center for Cell Signaling and Department of Microbiology, Immunology and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA;
| | - Shirish Shenolikar
- Signature Research Programs in Cardiovascular and Metabolic Disorders and Neuroscience and Behavioral Disorders, Duke-NUS Medical School, Singapore 169857
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24
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Bertran MT, Mouilleron S, Zhou Y, Bajaj R, Uliana F, Kumar GS, van Drogen A, Lee R, Banerjee JJ, Hauri S, O'Reilly N, Gstaiger M, Page R, Peti W, Tapon N. ASPP proteins discriminate between PP1 catalytic subunits through their SH3 domain and the PP1 C-tail. Nat Commun 2019; 10:771. [PMID: 30770806 PMCID: PMC6377682 DOI: 10.1038/s41467-019-08686-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 01/25/2019] [Indexed: 11/26/2022] Open
Abstract
Serine/threonine phosphatases such as PP1 lack substrate specificity and associate with a large array of targeting subunits to achieve the requisite selectivity. The tumour suppressor ASPP (apoptosis-stimulating protein of p53) proteins associate with PP1 catalytic subunits and are implicated in multiple functions from transcriptional regulation to cell junction remodelling. Here we show that Drosophila ASPP is part of a multiprotein PP1 complex and that PP1 association is necessary for several in vivo functions of Drosophila ASPP. We solve the crystal structure of the human ASPP2/PP1 complex and show that ASPP2 recruits PP1 using both its canonical RVxF motif, which binds the PP1 catalytic domain, and its SH3 domain, which engages the PP1 C-terminal tail. The ASPP2 SH3 domain can discriminate between PP1 isoforms using an acidic specificity pocket in the n-Src domain, providing an exquisite mechanism where multiple motifs are used combinatorially to tune binding affinity to PP1.
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Affiliation(s)
- M Teresa Bertran
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Stéphane Mouilleron
- Structural Biology - Science Technology Platform, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK.
| | - Yanxiang Zhou
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Rakhi Bajaj
- Chemistry and Biochemistry Department, University of Arizona, 1041 E. Lowell Street, Biosciences West, 517, Tucson, AZ, 85721, USA
| | - Federico Uliana
- Department of Biology, Institute of Molecular Systems Biology, ETH Zürich, 8093, Zürich, Switzerland
| | - Ganesan Senthil Kumar
- Chemistry and Biochemistry Department, University of Arizona, 1041 E. Lowell Street, Biosciences West, 517, Tucson, AZ, 85721, USA
| | - Audrey van Drogen
- Department of Biology, Institute of Molecular Systems Biology, ETH Zürich, 8093, Zürich, Switzerland
| | - Rebecca Lee
- Structural Biology - Science Technology Platform, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Jennifer J Banerjee
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Simon Hauri
- Department of Biology, Institute of Molecular Systems Biology, ETH Zürich, 8093, Zürich, Switzerland
| | - Nicola O'Reilly
- Peptide Chemistry Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Matthias Gstaiger
- Department of Biology, Institute of Molecular Systems Biology, ETH Zürich, 8093, Zürich, Switzerland
| | - Rebecca Page
- Chemistry and Biochemistry Department, University of Arizona, 1041 E. Lowell Street, Biosciences West, 517, Tucson, AZ, 85721, USA
| | - Wolfgang Peti
- Chemistry and Biochemistry Department, University of Arizona, 1041 E. Lowell Street, Biosciences West, 517, Tucson, AZ, 85721, USA
| | - Nicolas Tapon
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK.
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25
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Moura M, Conde C. Phosphatases in Mitosis: Roles and Regulation. Biomolecules 2019; 9:E55. [PMID: 30736436 PMCID: PMC6406801 DOI: 10.3390/biom9020055] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 01/31/2019] [Accepted: 02/01/2019] [Indexed: 02/07/2023] Open
Abstract
Mitosis requires extensive rearrangement of cellular architecture and of subcellular structures so that replicated chromosomes can bind correctly to spindle microtubules and segregate towards opposite poles. This process originates two new daughter nuclei with equal genetic content and relies on highly-dynamic and tightly regulated phosphorylation of numerous cell cycle proteins. A burst in protein phosphorylation orchestrated by several conserved kinases occurs as cells go into and progress through mitosis. The opposing dephosphorylation events are catalyzed by a small set of protein phosphatases, whose importance for the accuracy of mitosis is becoming increasingly appreciated. This review will focus on the established and emerging roles of mitotic phosphatases, describe their structural and biochemical properties, and discuss recent advances in understanding the regulation of phosphatase activity and function.
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Affiliation(s)
- Margarida Moura
- IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal.
- i3S-Instituto de Investigação e Inovação em Saúde da Universidade do Porto, 4200-135, Porto, Portugal.
- Programa Doutoral em Biologia Molecular e Celular (MCbiology), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, 4050-313 Porto, Portugal.
| | - Carlos Conde
- IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal.
- i3S-Instituto de Investigação e Inovação em Saúde da Universidade do Porto, 4200-135, Porto, Portugal.
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26
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Structure-Guided Exploration of SDS22 Interactions with Protein Phosphatase PP1 and the Splicing Factor BCLAF1. Structure 2019; 27:507-518.e5. [PMID: 30661852 DOI: 10.1016/j.str.2018.12.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 10/09/2018] [Accepted: 12/03/2018] [Indexed: 01/29/2023]
Abstract
SDS22 is an ancient regulator of protein phosphatase-1 (PP1). Our crystal structure of SDS22 shows that its twelve leucine-rich repeats adopt a banana-shaped fold that is shielded from solvent by capping domains at its extremities. Subsequent modeling and biochemical studies revealed that the concave side of SDS22 likely interacts with PP1 helices α5 and α6, which are distal from the binding sites of many previously described PP1 interactors. Accordingly, we found that SDS22 acts as a "third" subunit of multiple PP1 holoenzymes. The crystal structure of SDS22 also revealed a large basic surface patch that enables binding of a phosphorylated form of splicing factor BCLAF1. Taken together, our data provide insights into the formation of PP1:SDS22 and the recruitment of additional interaction proteins, such as BCLAF1.
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27
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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. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2019; 1866:16-30. [PMID: 30056088 PMCID: PMC7114192 DOI: 10.1016/j.bbamcr.2018.07.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [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.
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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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28
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The split protein phosphatase system. Biochem J 2018; 475:3707-3723. [PMID: 30523060 PMCID: PMC6282683 DOI: 10.1042/bcj20170726] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 10/29/2018] [Accepted: 11/01/2018] [Indexed: 12/14/2022]
Abstract
Reversible phosphorylation of proteins is a post-translational modification that regulates all aspect of life through the antagonistic action of kinases and phosphatases. Protein kinases are well characterized, but protein phosphatases have been relatively neglected. Protein phosphatase 1 (PP1) catalyzes the dephosphorylation of a major fraction of phospho-serines and phospho-threonines in cells and thereby controls a broad range of cellular processes. In this review, I will discuss how phosphatases were discovered, how the view that they were unselective emerged and how recent findings have revealed their exquisite selectivity. Unlike kinases, PP1 phosphatases are obligatory heteromers composed of a catalytic subunit bound to one (or two) non-catalytic subunit(s). Based on an in-depth study of two holophosphatases, I propose the following: selective dephosphorylation depends on the assembly of two components, the catalytic subunit and the non-catalytic subunit, which serves as a high-affinity substrate receptor. Because functional complementation of the two modules is required to produce a selective holophosphatase, one can consider that they are split enzymes. The non-catalytic subunit was often referred to as a regulatory subunit, but it is, in fact, an essential component of the holoenzyme. In this model, a phosphatase and its array of mostly orphan substrate receptors constitute the split protein phosphatase system. The set of potentially generalizable principles outlined in this review may facilitate the study of these poorly understood enzymes and the identification of their physiological substrates.
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29
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Choy MS, Bolik-Coulon N, Archuleta TL, Peti W, Page R. The structure of SDS22 provides insights into the mechanism of heterodimer formation with PP1. Acta Crystallogr F Struct Biol Commun 2018; 74:817-824. [PMID: 30511677 PMCID: PMC6277963 DOI: 10.1107/s2053230x18016503] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 11/19/2018] [Indexed: 01/18/2023] Open
Abstract
Protein phosphatase 1 (PP1) dephosphorylates hundreds of key biological targets by associating with nearly 200 regulatory proteins to form highly specific holoenzymes. The vast majority of regulators are intrinsically disordered proteins (IDPs) and bind PP1 via short linear motifs within their intrinsically disordered regions. One of the most ancient PP1 regulators is SDS22, a protein that is conserved from yeast to mammals. Sequence analysis of SDS22 revealed that it is a leucine-rich repeat (LRR) protein, suggesting that SDS22, unlike nearly every other known PP1 regulator, is not an IDP but instead is fully structured. Here, the 2.9 Å resolution crystal structure of human SDS22 in space group P212121 is reported. SDS22 adopts an LRR fold with the horseshoe-like curvature typical for this family of proteins. The structure results in surfaces with distinct chemical characteristics that are likely to be critical for PP1 binding.
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Affiliation(s)
- Meng S. Choy
- Chemistry and Biochemistry, University of Arizona, 1041 East Lowell Drive, Biosciences West, Tucson, AZ 85281, USA
| | - Nicolas Bolik-Coulon
- Chemistry and Biochemistry, University of Arizona, 1041 East Lowell Drive, Biosciences West, Tucson, AZ 85281, USA
| | - Tara L. Archuleta
- Chemistry and Biochemistry, University of Arizona, 1041 East Lowell Drive, Biosciences West, Tucson, AZ 85281, USA
| | - Wolfgang Peti
- Chemistry and Biochemistry, University of Arizona, 1041 East Lowell Drive, Biosciences West, Tucson, AZ 85281, USA
| | - Rebecca Page
- Chemistry and Biochemistry, University of Arizona, 1041 East Lowell Drive, Biosciences West, Tucson, AZ 85281, USA
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30
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Yu J, Deng T, Xiang S. Structural basis for protein phosphatase 1 recruitment by glycogen‐targeting subunits. FEBS J 2018; 285:4646-4659. [DOI: 10.1111/febs.14699] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 10/15/2018] [Accepted: 11/09/2018] [Indexed: 10/27/2022]
Affiliation(s)
- Jun Yu
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety Shanghai Institute of Nutrition and Health Shanghai Institutes for Biological Sciences University of Chinese Academy of Sciences Chinese Academy of Sciences Shanghai China
| | - Tingting Deng
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety Shanghai Institute of Nutrition and Health Shanghai Institutes for Biological Sciences University of Chinese Academy of Sciences Chinese Academy of Sciences Shanghai China
| | - Song Xiang
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety Shanghai Institute of Nutrition and Health Shanghai Institutes for Biological Sciences University of Chinese Academy of Sciences Chinese Academy of Sciences Shanghai China
- Key laboratory of Immune Microenvironment and Disease (Ministry of Education) Tianjin Medical University China
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31
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Salvi F, Trebacz M, Kokot T, Hoermann B, Rios P, Barabas O, Kӧhn M. Effects of stably incorporated iron on protein phosphatase-1 structure and activity. FEBS Lett 2018; 592:4028-4038. [PMID: 30403291 PMCID: PMC6587554 DOI: 10.1002/1873-3468.13284] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 10/04/2018] [Accepted: 10/30/2018] [Indexed: 01/21/2023]
Abstract
Protein phosphatase‐1 (PP1) drives a large amount of phosphoSer/Thr protein dephosphorylations in eukaryotes to counteract multiple kinases in signaling pathways. The phosphatase requires divalent metal cations for catalytic activity and contains iron naturally. Iron has been suggested to have an influence on PP1 activity through Fe2+ and Fe3+ oxidation states. However, much biochemical and all structural data have been obtained with recombinant PP1 containing Mn2+ ions. Purifying iron‐containing PP1 from Escherichia coli has thus far not been possible. Here, we present the preparation, characterization, and structure of iron‐bound PP1α in inactive and active states. We establish a key role for the electronic/redox properties of iron in PP1 activity and shed light on the difference in substrate specificity between iron‐ and manganese‐containing PP1.
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Affiliation(s)
- Francesca Salvi
- Genome Biology UnitEuropean Molecular Biology LaboratoryHeidelbergGermany
| | - Malgorzata Trebacz
- Faculty of Biology and Centre for Biological Signalling Studies (BIOSS)University of FreiburgGermany
| | - Thomas Kokot
- Faculty of Biology and Centre for Biological Signalling Studies (BIOSS)University of FreiburgGermany
| | - Bernhard Hoermann
- Faculty of Biology and Centre for Biological Signalling Studies (BIOSS)University of FreiburgGermany
- Faculty of BiosciencesCollaboration for Joint PhD Degree between EMBL and Heidelberg UniversityGermany
| | - Pablo Rios
- Faculty of Biology and Centre for Biological Signalling Studies (BIOSS)University of FreiburgGermany
| | - Orsolya Barabas
- Structural and Computational Biology UnitEuropean Molecular Biology LaboratoryHeidelbergGermany
| | - Maja Kӧhn
- Genome Biology UnitEuropean Molecular Biology LaboratoryHeidelbergGermany
- Faculty of Biology and Centre for Biological Signalling Studies (BIOSS)University of FreiburgGermany
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32
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Kumar GS, Choy MS, Koveal DM, Lorinsky MK, Lyons SP, Kettenbach AN, Page R, Peti W. Identification of the substrate recruitment mechanism of the muscle glycogen protein phosphatase 1 holoenzyme. SCIENCE ADVANCES 2018; 4:eaau6044. [PMID: 30443599 PMCID: PMC6235537 DOI: 10.1126/sciadv.aau6044] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 10/15/2018] [Indexed: 05/04/2023]
Abstract
Glycogen is the primary storage form of glucose. Glycogen synthesis and breakdown are tightly controlled by glycogen synthase (GYS) and phosphorylase, respectively. The enzyme responsible for dephosphorylating GYS and phosphorylase, which results in their activation (GYS) or inactivation (phosphorylase) to robustly stimulate glycogen synthesis, is protein phosphatase 1 (PP1). However, our understanding of how PP1 recruits these substrates is limited. Here, we show how PP1, together with its muscle glycogen-targeting (GM) regulatory subunit, recruits and selectively dephosphorylates its substrates. Our molecular data reveal that the GM carbohydrate binding module (GM CBM21), which is amino-terminal to the GM PP1 binding domain, has a dual function in directing PP1 substrate specificity: It either directly recruits substrates (i.e., GYS) or recruits them indirectly by localization (via glycogen for phosphorylase). Our data provide the molecular basis for PP1 regulation by GM and reveal how PP1-mediated dephosphorylation is driven by scaffolding-based substrate recruitment.
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Affiliation(s)
- Ganesan Senthil Kumar
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Meng S. Choy
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Dorothy M. Koveal
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912, USA
| | - Michael K. Lorinsky
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, Providence, RI 02912, USA
| | - Scott P. Lyons
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Lebanon, NH 03756, USA
| | - Arminja N. Kettenbach
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Lebanon, NH 03756, USA
| | - Rebecca Page
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Wolfgang Peti
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
- Corresponding author.
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33
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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] [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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34
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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: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [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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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: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [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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36
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Jia Q, Lin Y, Gou X, He L, Shen D, Chen D, Xie W, Lu Y. Legionella pneumophila effector WipA, a bacterial PPP protein phosphatase with PTP activity. Acta Biochim Biophys Sin (Shanghai) 2018; 50:547-554. [PMID: 29701815 DOI: 10.1093/abbs/gmy042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Indexed: 11/12/2022] Open
Abstract
The gram-negative bacterium Legionella pneumophila invades human's lung and causes Legionnaires' disease. To benefit its survival and replication in cellular milieu, L. pneumophila secrets at least 330 effector proteins into host cells. We found that the effector WipA has the protein tyrosine phosphatase (PTP) activity but does not depend on the classical CX5R motif for activity, suggesting that WipA is an unconventional PTP. Meanwhile, the presence of three other highly conserved motifs typically seen in protein serine/threonine phosphatases and the poor inhibition of WipA activity by okadaic acid led us to propose that WipA is a bacterial protein phosphatase. In addition, the determination of the 2.55-Å crystal structure of WipA revealed that WipA resembles cold-active protein tyrosine phosphatase (CAPTPase), and therefore very likely shares the same catalytic mechanism.
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Affiliation(s)
- Qian Jia
- School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou 510275, China
| | - Yun Lin
- School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
- Biomedical Center of Sun Yat-sen University, Guangzhou 510275, China
| | - Xuejing Gou
- School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
- Biomedical Center of Sun Yat-sen University, Guangzhou 510275, China
| | - Lei He
- School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
- Biomedical Center of Sun Yat-sen University, Guangzhou 510275, China
| | - Dong Shen
- School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
- Biomedical Center of Sun Yat-sen University, Guangzhou 510275, China
| | - Dongni Chen
- School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
- Biomedical Center of Sun Yat-sen University, Guangzhou 510275, China
| | - Wei Xie
- School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou 510275, China
| | - Yongjun Lu
- School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
- Biomedical Center of Sun Yat-sen University, Guangzhou 510275, China
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37
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Adeno-associated virus Rep proteins antagonize phosphatase PP1 to counteract KAP1 repression of the latent viral genome. Proc Natl Acad Sci U S A 2018; 115:E3529-E3538. [PMID: 29581310 DOI: 10.1073/pnas.1721883115] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Adeno-associated virus (AAV) is a small human Dependovirus whose low immunogenicity and capacity for long-term persistence have led to its widespread use as vector for gene therapy. Despite great recent successes in AAV-based gene therapy, further improvements in vector technology may be hindered by an inadequate understanding of various aspects of basic AAV biology. AAV is unique in that its replication is largely dependent on a helper virus and cellular factors. In the absence of helper virus coinfection, wild-type AAV establishes latency through mechanisms that are not yet fully understood. Challenging the currently held model for AAV latency, we show here that the corepressor Krüppel-associated box domain-associated protein 1 (KAP1) binds the latent AAV2 genome at the rep ORF, leading to trimethylation of AAV2-associated histone 3 lysine 9 and that the inactivation of KAP1 repression is necessary for AAV2 reactivation and replication. We identify a viral mechanism for the counteraction of KAP1 in which interference with the KAP1 phosphatase protein phosphatase 1 (PP1) by the AAV2 Rep proteins mediates enhanced phosphorylation of KAP1-S824 and thus relief from KAP1 repression. Furthermore, we show that this phenomenon involves recruitment of the NIPP1 (nuclear inhibitor of PP1)-PP1α holoenzyme to KAP1 in a manner dependent upon the NIPP1 FHA domain, identifying NIPP1 as an interaction partner for KAP1 and shedding light on the mechanism through which PP1 regulates cellular KAP1 activity.
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38
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The protein phosphatase 1 regulator NIPP1 is essential for mammalian spermatogenesis. Sci Rep 2017; 7:13364. [PMID: 29042623 PMCID: PMC5645368 DOI: 10.1038/s41598-017-13809-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 09/29/2017] [Indexed: 12/22/2022] Open
Abstract
NIPP1 is one of the major nuclear interactors of protein phosphatase PP1. The deletion of NIPP1 in mice is early embryonic lethal, which has precluded functional studies in adult tissues. Hence, we have generated an inducible NIPP1 knockout model using a tamoxifen-inducible Cre recombinase transgene. The inactivation of the NIPP1 encoding alleles (Ppp1r8) in adult mice occurred very efficiently in testis and resulted in a gradual loss of germ cells, culminating in a Sertoli-cell only phenotype. Before the overt development of this phenotype Ppp1r8−/− testis showed a decreased proliferation and survival capacity of cells of the spermatogenic lineage. A reduced proliferation was also detected after the tamoxifen-induced removal of NIPP1 from cultured testis slices and isolated germ cells enriched for undifferentiated spermatogonia, hinting at a testis-intrinsic defect. Consistent with the observed phenotype, RNA sequencing identified changes in the transcript levels of cell-cycle and apoptosis regulating genes in NIPP1-depleted testis. We conclude that NIPP1 is essential for mammalian spermatogenesis because it is indispensable for the proliferation and survival of progenitor germ cells, including (un)differentiated spermatogonia.
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Charlier C, Bouvignies G, Pelupessy P, Walrant A, Marquant R, Kozlov M, De Ioannes P, Bolik-Coulon N, Sagan S, Cortes P, Aggarwal AK, Carlier L, Ferrage F. Structure and Dynamics of an Intrinsically Disordered Protein Region That Partially Folds upon Binding by Chemical-Exchange NMR. J Am Chem Soc 2017; 139:12219-12227. [PMID: 28780862 DOI: 10.1021/jacs.7b05823] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Many intrinsically disordered proteins (IDPs) and protein regions (IDRs) engage in transient, yet specific, interactions with a variety of protein partners. Often, if not always, interactions with a protein partner lead to partial folding of the IDR. Characterizing the conformational space of such complexes is challenging: in solution-state NMR, signals of the IDR in the interacting region become broad, weak, and often invisible, while X-ray crystallography only provides information on fully ordered regions. There is thus a need for a simple method to characterize both fully and partially ordered regions in the bound state of IDPs. Here, we introduce an approach based on monitoring chemical exchange by NMR to investigate the state of an IDR that folds upon binding through the observation of the free state of the protein. Structural constraints for the bound state are obtained from chemical shifts, and site-specific dynamics of the bound state are characterized by relaxation rates. The conformation of the interacting part of the IDR was determined and subsequently docked onto the structure of the folded partner. We apply the method to investigate the interaction between the disordered C-terminal region of Artemis and the DNA binding domain of Ligase IV. We show that we can accurately reproduce the structure of the core of the complex determined by X-ray crystallography and identify a broader interface. The method is widely applicable to the biophysical investigation of complexes of disordered proteins and folded proteins.
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Affiliation(s)
- Cyril Charlier
- Laboratoire des Biomolécules, Département de chimie, École normale supérieure, UPMC Université Paris 06, CNRS, PSL Research University , 24 rue Lhomond, Paris 75005, France.,Sorbonne Universités, UPMC Université Paris 06, École normale supérieure, CNRS, Laboratoire des Biomolécules (LBM) , Paris 75005, France
| | - Guillaume Bouvignies
- Laboratoire des Biomolécules, Département de chimie, École normale supérieure, UPMC Université Paris 06, CNRS, PSL Research University , 24 rue Lhomond, Paris 75005, France.,Sorbonne Universités, UPMC Université Paris 06, École normale supérieure, CNRS, Laboratoire des Biomolécules (LBM) , Paris 75005, France
| | - Philippe Pelupessy
- Laboratoire des Biomolécules, Département de chimie, École normale supérieure, UPMC Université Paris 06, CNRS, PSL Research University , 24 rue Lhomond, Paris 75005, France.,Sorbonne Universités, UPMC Université Paris 06, École normale supérieure, CNRS, Laboratoire des Biomolécules (LBM) , Paris 75005, France
| | - Astrid Walrant
- Laboratoire des Biomolécules, Département de chimie, École normale supérieure, UPMC Université Paris 06, CNRS, PSL Research University , 24 rue Lhomond, Paris 75005, France.,Sorbonne Universités, UPMC Université Paris 06, École normale supérieure, CNRS, Laboratoire des Biomolécules (LBM) , Paris 75005, France
| | - Rodrigue Marquant
- Laboratoire des Biomolécules, Département de chimie, École normale supérieure, UPMC Université Paris 06, CNRS, PSL Research University , 24 rue Lhomond, Paris 75005, France.,Sorbonne Universités, UPMC Université Paris 06, École normale supérieure, CNRS, Laboratoire des Biomolécules (LBM) , Paris 75005, France
| | - Mikhail Kozlov
- Department of Medicine, Immunology Institute, Icahn School of Medicine at Mount Sinai , 1425 Madison Avenue, New York, New York 10029, United States
| | - Pablo De Ioannes
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai , 1425 Madison Avenue, New York, New York 10029, United States
| | - Nicolas Bolik-Coulon
- Laboratoire des Biomolécules, Département de chimie, École normale supérieure, UPMC Université Paris 06, CNRS, PSL Research University , 24 rue Lhomond, Paris 75005, France.,Sorbonne Universités, UPMC Université Paris 06, École normale supérieure, CNRS, Laboratoire des Biomolécules (LBM) , Paris 75005, France
| | - Sandrine Sagan
- Laboratoire des Biomolécules, Département de chimie, École normale supérieure, UPMC Université Paris 06, CNRS, PSL Research University , 24 rue Lhomond, Paris 75005, France.,Sorbonne Universités, UPMC Université Paris 06, École normale supérieure, CNRS, Laboratoire des Biomolécules (LBM) , Paris 75005, France
| | - Patricia Cortes
- Department of Medicine, Immunology Institute, Icahn School of Medicine at Mount Sinai , 1425 Madison Avenue, New York, New York 10029, United States.,Department of Molecular, Cellular and Biomedical Science, CUNY School of Medicine, City College of New York , 160 Convent Avenue, New York, New York 10031, United States
| | - Aneel K Aggarwal
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai , 1425 Madison Avenue, New York, New York 10029, United States
| | - Ludovic Carlier
- Laboratoire des Biomolécules, Département de chimie, École normale supérieure, UPMC Université Paris 06, CNRS, PSL Research University , 24 rue Lhomond, Paris 75005, France.,Sorbonne Universités, UPMC Université Paris 06, École normale supérieure, CNRS, Laboratoire des Biomolécules (LBM) , Paris 75005, France
| | - Fabien Ferrage
- Laboratoire des Biomolécules, Département de chimie, École normale supérieure, UPMC Université Paris 06, CNRS, PSL Research University , 24 rue Lhomond, Paris 75005, France.,Sorbonne Universités, UPMC Université Paris 06, École normale supérieure, CNRS, Laboratoire des Biomolécules (LBM) , Paris 75005, France
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Aubol BE, Hailey KL, Fattet L, Jennings PA, Adams JA. Redirecting SR Protein Nuclear Trafficking through an Allosteric Platform. J Mol Biol 2017; 429:2178-2191. [PMID: 28576472 DOI: 10.1016/j.jmb.2017.05.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 05/22/2017] [Accepted: 05/25/2017] [Indexed: 12/20/2022]
Abstract
Although phosphorylation directs serine-arginine (SR) proteins from nuclear storage speckles to the nucleoplasm for splicing function, dephosphorylation paradoxically induces similar movement, raising the question of how such chemical modifications are balanced in these essential splicing factors. In this new study, we investigated the interaction of protein phosphatase 1 (PP1) with the SR protein splicing factor (SRSF1) to understand the foundation of these opposing effects in the nucleus. We found that RNA recognition motif 1 (RRM1) in SRSF1 binds PP1 and represses its catalytic function through an allosteric mechanism. Disruption of RRM1-PP1 interactions reduces the phosphorylation status of the RS domain in vitro and in cells, redirecting SRSF1 in the nucleus. The data imply that an allosteric SR protein-phosphatase platform balances phosphorylation levels in a "goldilocks" region for the proper subnuclear storage of an SR protein splicing factor.
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Affiliation(s)
- Brandon E Aubol
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093-0636, USA
| | - Kendra L Hailey
- Department of Chemistry & Biochemistry, University of California, San Diego, La Jolla, CA 92093-0636, USA
| | - Laurent Fattet
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093-0636, USA
| | - Patricia A Jennings
- Department of Chemistry & Biochemistry, University of California, San Diego, La Jolla, CA 92093-0636, USA
| | - Joseph A Adams
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093-0636, USA.
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41
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Mouse Rif1 is a regulatory subunit of protein phosphatase 1 (PP1). Sci Rep 2017; 7:2119. [PMID: 28522851 PMCID: PMC5437018 DOI: 10.1038/s41598-017-01910-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 02/13/2017] [Indexed: 12/29/2022] Open
Abstract
Rif1 is a conserved protein that plays essential roles in orchestrating DNA replication timing, controlling nuclear architecture, telomere length and DNA repair. However, the relationship between these different roles, as well as the molecular basis of Rif1 function is still unclear. The association of Rif1 with insoluble nuclear lamina has thus far hampered exhaustive characterization of the associated protein complexes. We devised a protocol that overcomes this problem, and were thus able to discover a number of novel Rif1 interactors, involved in chromatin metabolism and phosphorylation. Among them, we focus here on PP1. Data from different systems have suggested that Rif1-PP1 interaction is conserved and has important biological roles. Using mutagenesis, NMR, isothermal calorimetry and surface plasmon resonance we demonstrate that Rif1 is a high-affinity PP1 adaptor, able to out-compete the well-established PP1-inhibitor I2 in vitro. Our conclusions have important implications for understanding Rif1 diverse roles and the relationship between the biological processes controlled by Rif1.
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42
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Biogenesis and activity regulation of protein phosphatase 1. Biochem Soc Trans 2017; 45:89-99. [DOI: 10.1042/bst20160154] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 11/06/2016] [Accepted: 11/16/2016] [Indexed: 01/01/2023]
Abstract
Protein phosphatase 1 (PP1) is expressed in all eukaryotic cells and catalyzes a substantial fraction of phosphoserine/threonine dephosphorylation reactions. It forms stable complexes with PP1-interacting proteins (PIPs) that guide the phosphatase throughout its life cycle and control its fate and function. The diversity of PIPs is huge (≈200 in vertebrates), and most of them combine short linear motifs to form large and unique interaction interfaces with PP1. Many PIPs have separate domains for PP1 anchoring, PP1 regulation, substrate recruitment and subcellular targeting, which enable them to direct associated PP1 to a specific subset of substrates and mediate acute activity control. Hence, PP1 functions as the catalytic subunit of a large number of multimeric holoenzymes, each with its own subset of substrates and mechanism(s) of regulation.
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Molecular Insights into the Fungus-Specific Serine/Threonine Protein Phosphatase Z1 in Candida albicans. mBio 2016; 7:mBio.00872-16. [PMID: 27578752 PMCID: PMC4999541 DOI: 10.1128/mbio.00872-16] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The opportunistic pathogen Candida is one of the most common causes of nosocomial bloodstream infections. Because candidemia is associated with high mortality rates and because the incidences of multidrug-resistant Candida are increasing, efforts to identify novel targets for the development of potent antifungals are warranted. Here, we describe the structure and function of the first member of a family of protein phosphatases that is specific to fungi, protein phosphatase Z1 (PPZ1) from Candida albicans We show that PPZ1 not only is active but also is as susceptible to inhibition by the cyclic peptide inhibitor microcystin-LR as its most similar human homolog, protein phosphatase 1α (PP1α [GLC7 in the yeast Saccharomyces cerevisiae]). Unexpectedly, we also discovered that, despite its 66% sequence identity to PP1α, the catalytic domain of PPZ1 contains novel structural elements that are not present in PP1α. We then used activity and pulldown assays to show that these structural differences block a large subset of PP1/GLC7 regulatory proteins from effectively binding PPZ1, demonstrating that PPZ1 does not compete with GLC7 for its regulatory proteins. Equally important, these unique structural elements provide new pockets suitable for the development of PPZ1-specific inhibitors. Together, these studies not only reveal why PPZ1 does not negatively impact GLC7 activity in vivo but also demonstrate that the family of fungus-specific phosphatases-especially PPZ1 from C. albicans-are highly suitable targets for the development of novel drugs that specifically target C. albicans without cross-reacting with human phosphatases. IMPORTANCE Candida albicans is a medically important human pathogen that is the most common cause of fungal infections in humans. In particular, approximately 46,000 cases of health care-associated candidiasis occur each year in the United States. Because these infections are associated with high mortality rates and because multiple species of Candida are becoming increasingly resistant to antifungals, there are increasing efforts to identify novel targets that are essential for C. albicans virulence. Here we use structural and biochemical approaches to elucidate how a member of a fungus-specific family of enzymes, serine/threonine phosphatase PPZ1, functions in C. albicans We discovered multiple unique features of PPZ1 that explain why it does not cross-react with, and in turn compete for, PP1-specific regulators, a long-standing question in the field. Most importantly, however, these unique features identified PPZ1 as a potential target for the development of novel antifungal therapeutics that will provide new, safe, and potent treatments for candidiasis in humans.
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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] [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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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: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [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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Hafver TL, Hodne K, Wanichawan P, Aronsen JM, Dalhus B, Lunde PK, Lunde M, Martinsen M, Enger UH, Fuller W, Sjaastad I, Louch WE, Sejersted OM, Carlson CR. Protein Phosphatase 1c Associated with the Cardiac Sodium Calcium Exchanger 1 Regulates Its Activity by Dephosphorylating Serine 68-phosphorylated Phospholemman. J Biol Chem 2015; 291:4561-79. [PMID: 26668322 DOI: 10.1074/jbc.m115.677898] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Indexed: 11/06/2022] Open
Abstract
The sodium (Na(+))-calcium (Ca(2+)) exchanger 1 (NCX1) is an important regulator of intracellular Ca(2+) homeostasis. Serine 68-phosphorylated phospholemman (pSer-68-PLM) inhibits NCX1 activity. In the context of Na(+)/K(+)-ATPase (NKA) regulation, pSer-68-PLM is dephosphorylated by protein phosphatase 1 (PP1). PP1 also associates with NCX1; however, the molecular basis of this association is unknown. In this study, we aimed to analyze the mechanisms of PP1 targeting to the NCX1-pSer-68-PLM complex and hypothesized that a direct and functional NCX1-PP1 interaction is a prerequisite for pSer-68-PLM dephosphorylation. Using a variety of molecular techniques, we show that PP1 catalytic subunit (PP1c) co-localized, co-fractionated, and co-immunoprecipitated with NCX1 in rat cardiomyocytes, left ventricle lysates, and HEK293 cells. Bioinformatic analysis, immunoprecipitations, mutagenesis, pulldown experiments, and peptide arrays constrained PP1c anchoring to the K(I/V)FF motif in the first Ca(2+) binding domain (CBD) 1 in NCX1. This binding site is also partially in agreement with the extended PP1-binding motif K(V/I)FF-X5-8Φ1Φ2-X8-9-R. The cytosolic loop of NCX1, containing the K(I/V)FF motif, had no effect on PP1 activity in an in vitro assay. Dephosphorylation of pSer-68-PLM in HEK293 cells was not observed when NCX1 was absent, when the K(I/V)FF motif was mutated, or when the PLM- and PP1c-binding sites were separated (mimicking calpain cleavage of NCX1). Co-expression of PLM and NCX1 inhibited NCX1 current (both modes). Moreover, co-expression of PLM with NCX1(F407P) (mutated K(I/V)FF motif) resulted in the current being completely abolished. In conclusion, NCX1 is a substrate-specifying PP1c regulator protein, indirectly regulating NCX1 activity through pSer-68-PLM dephosphorylation.
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Affiliation(s)
- Tandekile Lubelwana Hafver
- From the Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, 0450 Oslo, Norway, the KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, 0316 Oslo, Norway
| | - Kjetil Hodne
- From the Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, 0450 Oslo, Norway, the KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, 0316 Oslo, Norway, the Department of Basic Sciences and Aquatic Medicine, Norwegian University of Life Sciences (NMBU), 0454 Oslo, Norway
| | - Pimthanya Wanichawan
- From the Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, 0450 Oslo, Norway, the KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, 0316 Oslo, Norway
| | - Jan Magnus Aronsen
- From the Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, 0450 Oslo, Norway, the Bjørknes College, Oslo, Norway
| | - Bjørn Dalhus
- the Department of Microbiology, Oslo University Hospital, Rikshospitalet, 0424 Oslo, Norway, the Department of Medical Biochemistry, Institute for Clinical Medicine, University of Oslo, 0424 Oslo, Norway and
| | - Per Kristian Lunde
- From the Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, 0450 Oslo, Norway, the KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, 0316 Oslo, Norway
| | - Marianne Lunde
- From the Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, 0450 Oslo, Norway, the KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, 0316 Oslo, Norway
| | - Marita Martinsen
- From the Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, 0450 Oslo, Norway, the KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, 0316 Oslo, Norway
| | - Ulla Helene Enger
- From the Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, 0450 Oslo, Norway, the KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, 0316 Oslo, Norway
| | - William Fuller
- the Cardiovascular and Diabetes Medicine, School of Medicine, University of Dundee, Dundee, Scotland, United Kingdom DD1 9SY
| | - Ivar Sjaastad
- From the Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, 0450 Oslo, Norway, the KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, 0316 Oslo, Norway
| | - William Edward Louch
- From the Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, 0450 Oslo, Norway, the KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, 0316 Oslo, Norway
| | - Ole Mathias Sejersted
- From the Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, 0450 Oslo, Norway, the KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, 0316 Oslo, Norway
| | - Cathrine Rein Carlson
- From the Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, 0450 Oslo, Norway, the KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, 0316 Oslo, Norway,
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Rebelo S, Santos M, Martins F, da Cruz e Silva EF, da Cruz e Silva OA. Protein phosphatase 1 is a key player in nuclear events. Cell Signal 2015; 27:2589-98. [DOI: 10.1016/j.cellsig.2015.08.007] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 07/31/2015] [Accepted: 08/10/2015] [Indexed: 12/17/2022]
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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] [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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Choy MS, Yusoff P, Lee IC, Newton JC, Goh CW, Page R, Shenolikar S, Peti W. Structural and Functional Analysis of the GADD34:PP1 eIF2α Phosphatase. Cell Rep 2015; 11:1885-91. [PMID: 26095357 DOI: 10.1016/j.celrep.2015.05.043] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 04/27/2015] [Accepted: 05/27/2015] [Indexed: 11/27/2022] Open
Abstract
The attenuation of protein synthesis via the phosphorylation of eIF2α is a major stress response of all eukaryotic cells. The growth-arrest- and DNA-damage-induced transcript 34 (GADD34) bound to the serine/threonine protein phosphatase 1 (PP1) is the necessary eIF2α phosphatase complex that returns mammalian cells to normal protein synthesis following stress. The molecular basis by which GADD34 recruits PP1 and its substrate eIF2α are not fully understood, hindering our understanding of the remarkable selectivity of the GADD34:PP1 phosphatase for eIF2α. Here, we report detailed structural and functional analyses of the GADD34:PP1 holoenzyme and its recruitment of eIF2α. The data highlight independent interactions of PP1 and eIF2α with GADD34, demonstrating that GADD34 functions as a scaffold both in vitro and in cells. This work greatly enhances our molecular understanding of a major cellular eIF2α phosphatase and establishes the foundation for future translational work.
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Affiliation(s)
- Meng S Choy
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, Providence, RI 02912, USA
| | - Permeen Yusoff
- Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-NUS Graduate Medical School, Singapore 169857, Singapore
| | - Irene C Lee
- Signature Research Program in Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School, Singapore 169857, Singapore
| | - Jocelyn C Newton
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912, USA
| | - Catherine W Goh
- Signature Research Program in Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School, Singapore 169857, Singapore
| | - Rebecca Page
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912, USA
| | - Shirish Shenolikar
- Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-NUS Graduate Medical School, Singapore 169857, Singapore; Signature Research Program in Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School, Singapore 169857, Singapore.
| | - Wolfgang Peti
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, Providence, RI 02912, USA; Department of Chemistry, Brown University, Providence, RI 02912, USA.
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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] [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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