1
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Zhang Y, Sabatini R. Leishmania PNUTS discriminates between PP1 catalytic subunits through an RVxF-ΦΦ-F motif and polymorphisms in the PP1 C-tail and catalytic domain. J Biol Chem 2023; 299:105432. [PMID: 37926279 PMCID: PMC10731240 DOI: 10.1016/j.jbc.2023.105432] [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: 09/08/2023] [Revised: 10/10/2023] [Accepted: 10/23/2023] [Indexed: 11/07/2023] Open
Abstract
Phosphoprotein phosphatase 1 (PP1) associates with specific regulatory subunits to achieve, among other functions, substrate selectivity. Among the eight PP1 isotypes in Leishmania, PP1-8e associates with the regulatory protein PNUTS along with the structural factors JBP3 and Wdr82 in the PJW/PP1 complex that modulates RNA polymerase II (pol II) phosphorylation and transcription termination. Little is known regarding interactions involved in PJW/PP1 complex formation, including how PP1-8e is the selective isotype associated with PNUTS. Here, we show that PNUTS uses an established RVxF-ΦΦ-F motif to bind the PP1 catalytic domain with similar interfacial interactions as mammalian PP1-PNUTS and noncanonical motifs. These atypical interactions involve residues within the PP1-8e catalytic domain and N and C terminus for isoform-specific regulator binding. This work advances our understanding of PP1 isoform selectivity and reveals key roles of PP1 residues in regulator binding. We also explore the role of PNUTS as a scaffold protein for the complex by identifying the C-terminal region involved in binding JBP3 and Wdr82 and impact of PNUTS on the stability of complex components and function in pol II transcription in vivo. Taken together, these studies provide a potential mechanism where multiple motifs within PNUTS are used combinatorially to tune binding affinity to PP1, and the C terminus for JBP3 and Wdr82 association, in the Leishmania PJW/PP1 complex. Overall, our data provide insights in the formation of the PJW/PP1 complex involved in regulating pol II transcription in divergent protozoans where little is understood.
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Affiliation(s)
- Yang Zhang
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Robert Sabatini
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA.
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2
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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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3
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Djemal R, Bradai M, Amor F, Hanin M, Ebel C. Wheat type one protein phosphatase promotes salt and osmotic stress tolerance in arabidopsis via auxin-mediated remodelling of the root system. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2023; 201:107832. [PMID: 37327648 DOI: 10.1016/j.plaphy.2023.107832] [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: 02/13/2023] [Revised: 05/31/2023] [Accepted: 06/09/2023] [Indexed: 06/18/2023]
Abstract
The control of optimal root growth and plant stress responses depends largely on a variety of phytohormones among which auxin and brassinosteroids (BRs) are the most influential. We have previously reported that the durum wheat type 1 protein phosphatase TdPP1 participates in the control of root growth by modulating BR signaling. In this study, we pursue our understanding of how TdPP1 fulfills this regulatory function on root growth by evaluating the physiological and molecular responses of Arabidopsis TdPP1 over-expressing lines to abiotic stresses. Our results showed that when exposed to 300 mM Mannitol or 100 mM NaCl, the seedlings of TdPP1 over-expressors exhibit modified root architecture with higher lateral root density, and longer root hairs concomitant with a lower inhibition of the primary root growth. These lines also exhibit faster gravitropic response and a decrease in primary root growth inhibition when exposed to high concentrations of exogenous IAA. On another hand, a cross between TdPP1 overexpressors and DR5:GUS marker line was performed to monitor auxin accumulation in roots. Remarkably, the TdPP1 overexpression resulted in an enhanced auxin gradient under salt stress with a higher accumulation in primary and lateral root tips. Moreover, TdPP1 transgenics exhibit a significant induction of a subset of auxin-responsive genes under salt stress conditions. Therefore, our results reveal a role of PP1 in enhancing auxin signaling to help shape greater root plasticity thus improving plant stress resilience.
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Affiliation(s)
- Rania Djemal
- Plant Physiology and Functional Genomics Research Unit, Higher Institute of Biotechnology, University of Sfax, BP "1175", 3038, Sfax, Tunisia
| | - Mariem Bradai
- Plant Physiology and Functional Genomics Research Unit, Higher Institute of Biotechnology, University of Sfax, BP "1175", 3038, Sfax, Tunisia
| | - Fatma Amor
- Plant Physiology and Functional Genomics Research Unit, Higher Institute of Biotechnology, University of Sfax, BP "1175", 3038, Sfax, Tunisia
| | - Moez Hanin
- Plant Physiology and Functional Genomics Research Unit, Higher Institute of Biotechnology, University of Sfax, BP "1175", 3038, Sfax, Tunisia
| | - Chantal Ebel
- Plant Physiology and Functional Genomics Research Unit, Higher Institute of Biotechnology, University of Sfax, BP "1175", 3038, Sfax, Tunisia.
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4
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Calvi I, Schwager F, Gotta M. PP1 phosphatases control PAR-2 localization and polarity establishment in C. elegans embryos. J Cell Biol 2022; 221:213453. [PMID: 36083688 PMCID: PMC9467853 DOI: 10.1083/jcb.202201048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 06/28/2022] [Accepted: 08/08/2022] [Indexed: 01/12/2023] Open
Abstract
Cell polarity relies on the asymmetric distribution of the conserved PAR proteins, which is regulated by phosphorylation/dephosphorylation reactions. While the kinases involved have been well studied, the role of phosphatases remains poorly understood. In Caenorhabditis elegans zygotes, phosphorylation of the posterior PAR-2 protein by the atypical protein kinase PKC-3 inhibits PAR-2 cortical localization. Polarity establishment depends on loading of PAR-2 at the posterior cortex. We show that the PP1 phosphatases GSP-1 and GSP-2 are required for polarity establishment in embryos. We find that codepletion of GSP-1 and GSP-2 abrogates the cortical localization of PAR-2 and that GSP-1 and GSP-2 interact with PAR-2 via a PP1 docking motif in PAR-2. Mutating this motif in vivo, to prevent binding of PAR-2 to PP1, abolishes cortical localization of PAR-2, while optimizing this motif extends PAR-2 cortical localization. Our data suggest a model in which GSP-1/-2 counteracts PKC-3 phosphorylation of PAR-2, allowing its cortical localization at the posterior and polarization of the one-cell embryo.
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Affiliation(s)
- Ida Calvi
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Françoise Schwager
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Monica Gotta
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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5
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Kokot T, Köhn M. Emerging insights into serine/threonine-specific phosphoprotein phosphatase function and selectivity. J Cell Sci 2022; 135:277104. [DOI: 10.1242/jcs.259618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
ABSTRACT
Protein phosphorylation on serine and threonine residues is a widely distributed post-translational modification on proteins that acts to regulate their function. Phosphoprotein phosphatases (PPPs) contribute significantly to a plethora of cellular functions through the accurate dephosphorylation of phosphorylated residues. Most PPPs accomplish their purpose through the formation of complex holoenzymes composed of a catalytic subunit with various regulatory subunits. PPP holoenzymes then bind and dephosphorylate substrates in a highly specific manner. Despite the high prevalence of PPPs and their important role for cellular function, their mechanisms of action in the cell are still not well understood. Nevertheless, substantial experimental advancements in (phospho-)proteomics, structural and computational biology have contributed significantly to a better understanding of PPP biology in recent years. This Review focuses on recent approaches and provides an overview of substantial new insights into the complex mechanism of PPP holoenzyme regulation and substrate selectivity.
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Affiliation(s)
- Thomas Kokot
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg 1 , Freiburg 79104 , Germany
- University of Freiburg, 2 Faculty of Biology , Freiburg 79104 , Germany
| | - Maja Köhn
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg 1 , Freiburg 79104 , Germany
- University of Freiburg, 2 Faculty of Biology , Freiburg 79104 , Germany
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6
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Metabotropic Glutamate Receptors at Ribbon Synapses in the Retina and Cochlea. Cells 2022; 11:cells11071097. [PMID: 35406660 PMCID: PMC8998116 DOI: 10.3390/cells11071097] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 03/17/2022] [Accepted: 03/22/2022] [Indexed: 02/01/2023] Open
Abstract
Our senses define our view of the world. They allow us to adapt to environmental stimuli and are essential for communication and social behaviour. For most humans, seeing and hearing are central senses for their daily life. Our eyes and ears respond to an extraordinary broad range of stimuli covering about 12 log units of light intensity or acoustic power, respectively. The cellular basis is represented by sensory cells (photoreceptors in the retina and inner hair cells in the cochlea) that convert sensory inputs into electrical signals. Photoreceptors and inner hair cells have developed a specific pre-synaptic structure, termed synaptic ribbon, that is decorated with numerous vesicles filled with the excitatory neurotransmitter glutamate. At these ribbon synapses, glutamatergic signal transduction is guided by distinct sets of metabotropic glutamate receptors (mGluRs). MGluRs belong to group II and III of the receptor classification can inhibit neuronal activity, thus protecting neurons from overstimulation and subsequent degeneration. Consequently, dysfunction of mGluRs is associated with vision and hearing disorders. In this review, we introduce the principle characteristics of ribbon synapses and describe group II and III mGluRs in these fascinating structures in the retina and cochlea.
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7
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Matos B, Howl J, Jerónimo C, Fardilha M. Modulation of serine/threonine-protein phosphatase 1 (PP1) complexes: A promising approach in cancer treatment. Drug Discov Today 2021; 26:2680-2698. [PMID: 34390863 DOI: 10.1016/j.drudis.2021.08.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 04/23/2021] [Accepted: 08/05/2021] [Indexed: 01/21/2023]
Abstract
Cancer is the second leading cause of death worldwide. Despite the availability of numerous therapeutic options, tumor heterogeneity and chemoresistance have limited the success of these treatments, and the development of effective anticancer therapies remains a major focus in oncology research. The serine/threonine-protein phosphatase 1 (PP1) and its complexes have been recognized as potential drug targets. Research on the modulation of PP1 complexes is currently at an early stage, but has immense potential. Chemically diverse compounds have been developed to disrupt or stabilize different PP1 complexes in various cancer types, with the objective of inhibiting disease progression. Beneficial results obtained in vitro now require further pre-clinical and clinical validation. In conclusion, the modulation of PP1 complexes seems to be a promising, albeit challenging, therapeutic strategy for cancer.
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Affiliation(s)
- Bárbara Matos
- Laboratory of Signal Transduction, Department of Medical Sciences, Institute of Biomedicine-iBiMED, University of Aveiro, 3810-193 Aveiro, Portugal; Cancer Biology and Epigenetics Group, IPO Porto Research Center (CI-IPOP), Portuguese Institute of Oncology of Porto (IPO Porto), 4200-072 Porto, Portugal
| | - John Howl
- Molecular Pharmacology Group, Research Institute in Healthcare Science, University of Wolverhampton, Wolverhampton WV1 1LY, UK
| | - Carmen Jerónimo
- Cancer Biology and Epigenetics Group, IPO Porto Research Center (CI-IPOP), Portuguese Institute of Oncology of Porto (IPO Porto), 4200-072 Porto, Portugal; Department of Pathology and Molecular Immunology, Institute of Biomedical Sciences Abel Salazar, University of Porto (ICBAS-UP), 4050-513 Porto, Portugal
| | - Margarida Fardilha
- Laboratory of Signal Transduction, Department of Medical Sciences, Institute of Biomedicine-iBiMED, University of Aveiro, 3810-193 Aveiro, Portugal.
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8
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Xu L, Ali M, Duan W, Yuan X, Garba F, Mullen M, Sun B, Poser I, Duan H, Lu J, Tian R, Ge Y, Chu L, Pan W, Wang D, Hyman A, Green H, Li L, Dou Z, Liu D, Liu X, Yao X. Feedback control of PLK1 by Apolo1 ensures accurate chromosome segregation. Cell Rep 2021; 36:109343. [PMID: 34260926 PMCID: PMC8358895 DOI: 10.1016/j.celrep.2021.109343] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Revised: 04/01/2020] [Accepted: 06/15/2021] [Indexed: 12/12/2022] Open
Abstract
Stable transmission of genetic material during cell division requires accurate chromosome segregation. PLK1 dynamics at kinetochores control establishment of correct kinetochore-microtubule attachments and subsequent silencing of the spindle checkpoint. However, the regulatory mechanism responsible for PLK1 activity in prometaphase has not yet been affirmatively identified. Here we identify Apolo1, which tunes PLK1 activity for accurate kinetochore-microtubule attachments. Apolo1 localizes to kinetochores during early mitosis, and suppression of Apolo1 results in misaligned chromosomes. Using the fluorescence resonance energy transfer (FRET)-based PLK1 activity reporter, we found that Apolo1 sustains PLK1 kinase activity at kinetochores for accurate attachment during prometaphase. Apolo1 is a cognate substrate of PLK1, and the phosphorylation enables PP1γ to inactivate PLK1 by dephosphorylation. Mechanistically, Apolo1 constitutes a bridge between kinase and phosphatase, which governs PLK1 activity in prometaphase. These findings define a previously uncharacterized feedback loop by which Apolo1 provides fine-tuning for PLK1 to guide chromosome segregation in mitosis.
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Affiliation(s)
- Leilei Xu
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, University of Science & Technology of China, Hefei 230027, China; Keck Center for Molecular Imaging, Morehouse School of Medicine, Atlanta, GA 30310, USA
| | - Mahboob Ali
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, University of Science & Technology of China, Hefei 230027, China
| | - Wenxiu Duan
- Anhui Key Laboratory for Chemical Biology, Hefei National Center for Physical Sciences at Microscale, Hefei 230027, China
| | - Xiao Yuan
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, University of Science & Technology of China, Hefei 230027, China; Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China.
| | - Fatima Garba
- Keck Center for Molecular Imaging, Morehouse School of Medicine, Atlanta, GA 30310, USA
| | - McKay Mullen
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, University of Science & Technology of China, Hefei 230027, China; Keck Center for Molecular Imaging, Morehouse School of Medicine, Atlanta, GA 30310, USA
| | - Binwen Sun
- National Chromatographic Research and Analysis Center, Dalian 116023, China
| | - Ina Poser
- Max Planck Institute for Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Hequan Duan
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, University of Science & Technology of China, Hefei 230027, China; Keck Center for Molecular Imaging, Morehouse School of Medicine, Atlanta, GA 30310, USA; Anhui Key Laboratory for Chemical Biology, Hefei National Center for Physical Sciences at Microscale, Hefei 230027, China
| | - Jianlin Lu
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, University of Science & Technology of China, Hefei 230027, China
| | - Ruijun Tian
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yushu Ge
- Anhui Key Laboratory for Chemical Biology, Hefei National Center for Physical Sciences at Microscale, Hefei 230027, China
| | - Lingluo Chu
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, University of Science & Technology of China, Hefei 230027, China; Keck Center for Molecular Imaging, Morehouse School of Medicine, Atlanta, GA 30310, USA
| | - Weijun Pan
- Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Dongmei Wang
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, University of Science & Technology of China, Hefei 230027, China
| | - Anthony Hyman
- Max Planck Institute for Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Hadiyah Green
- Keck Center for Molecular Imaging, Morehouse School of Medicine, Atlanta, GA 30310, USA
| | - Lin Li
- Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Zhen Dou
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, University of Science & Technology of China, Hefei 230027, China; Anhui Key Laboratory for Chemical Biology, Hefei National Center for Physical Sciences at Microscale, Hefei 230027, China.
| | - Dan Liu
- Anhui Key Laboratory for Chemical Biology, Hefei National Center for Physical Sciences at Microscale, Hefei 230027, China.
| | - Xing Liu
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, University of Science & Technology of China, Hefei 230027, China; Keck Center for Molecular Imaging, Morehouse School of Medicine, Atlanta, GA 30310, USA.
| | - Xuebiao Yao
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, University of Science & Technology of China, Hefei 230027, China; Keck Center for Molecular Imaging, Morehouse School of Medicine, Atlanta, GA 30310, USA.
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9
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Specificity determinants of phosphoprotein phosphatases controlling kinetochore functions. Essays Biochem 2021; 64:325-336. [PMID: 32501472 DOI: 10.1042/ebc20190065] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 05/11/2020] [Accepted: 05/14/2020] [Indexed: 12/12/2022]
Abstract
Kinetochores are instrumental for accurate chromosome segregation by binding to microtubules in order to move chromosomes and by delaying anaphase onset through the spindle assembly checkpoint (SAC). Dynamic phosphorylation of kinetochore components is key to control these activities and is tightly regulated by temporal and spatial recruitment of kinases and phosphoprotein phosphatases (PPPs). Here we focus on PP1, PP2A-B56 and PP2A-B55, three PPPs that are important regulators of mitosis. Despite the fact that these PPPs share a very similar active site, they target unique ser/thr phosphorylation sites to control kinetochore function. Specificity is in part achieved by PPPs binding to short linear motifs (SLiMs) that guide their substrate specificity. SLiMs bind to conserved pockets on PPPs and are degenerate in nature, giving rise to a range of binding affinities. These SLiMs control the assembly of numerous substrate specifying complexes and their position and binding strength allow PPPs to target specific phosphorylation sites. In addition, the activity of PPPs is regulated by mitotic kinases and inhibitors, either directly at the activity level or through affecting PPP-SLiM interactions. Here, we discuss recent progress in understanding the regulation of PPP specificity and activity and how this controls kinetochore biology.
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10
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Khalife J, Fréville A, Gnangnon B, Pierrot C. The Multifaceted Role of Protein Phosphatase 1 in Plasmodium. Trends Parasitol 2020; 37:154-164. [PMID: 33036936 DOI: 10.1016/j.pt.2020.09.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 09/07/2020] [Accepted: 09/08/2020] [Indexed: 11/29/2022]
Abstract
Protein phosphatase type 1 (PP1) forms a wide range of Ser/Thr-specific phosphatase holoenzymes which contain one catalytic subunit (PP1c), present in all eukaryotic cells, associated with variable subunits known as regulatory proteins. It has recently been shown that regulators take a leading role in the organization and the control of PP1 functions. Many studies have addressed the role of these regulators in diverse organisms, including humans, and investigated their link to diseases. In this review we summarize recent advances on the role of PP1c in Plasmodium, its interactome and regulators. As a proof of concept, peptides interfering with the regulator binding capacity of PP1c were shown to inhibit the growth of P. falciparum, suggesting their potential as drug precursors.
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Affiliation(s)
- Jamal Khalife
- Center for Infection and Immunity of Lille, Biology of Apicomplexan Parasites, UMR 9017 CNRS, U1019 INSERM, Université de Lille, Institut Pasteur de Lille, Lille, France.
| | - Aline Fréville
- Center for Infection and Immunity of Lille, Biology of Apicomplexan Parasites, UMR 9017 CNRS, U1019 INSERM, Université de Lille, Institut Pasteur de Lille, Lille, France
| | - Bénédicte Gnangnon
- Center for Infection and Immunity of Lille, Biology of Apicomplexan Parasites, UMR 9017 CNRS, U1019 INSERM, Université de Lille, Institut Pasteur de Lille, Lille, France
| | - Christine Pierrot
- Center for Infection and Immunity of Lille, Biology of Apicomplexan Parasites, UMR 9017 CNRS, U1019 INSERM, Université de Lille, Institut Pasteur de Lille, Lille, France
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11
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Christensen KR, Nairn AC. cAMP-regulated phosphoproteins DARPP-32, ARPP16/19, and RCS modulate striatal signal transduction through protein kinases and phosphatases. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2020; 90:39-65. [PMID: 33706938 DOI: 10.1016/bs.apha.2020.09.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Decades of research led by Paul Greengard identified protein phosphorylation as a ubiquitous and vital post-translational modification involved in many neuronal signaling pathways. In particular, his discovery that second messenger-regulated protein phosphorylation plays a central role in the propagation and transduction of signals in the nervous system has been essential in understanding the molecular mechanisms of neuronal communication. The establishment of dopamine (DA) as an essential neurotransmitter in the central nervous system, combined with observations that DA activates G-protein-coupled receptors to control the production of cyclic adenosine monophosphate (cAMP) in postsynaptic neurons, has provided fundamental insight into the regulation of neurotransmission. Notably, DA signaling in the striatum is involved in many neurological functions such as control of locomotion, reward, addiction, and learning, among others. This review focuses on the history, characterization, and function of cAMP-mediated regulation of serine/threonine protein phosphatases and their role in DA-mediated signaling in striatal neurons. Several small, heat- and acid-stable proteins, including DARPP-32, RCS, and ARPP-16/19, were discovered by the Greengard laboratory to be regulated by DA- and cAMP signaling, and found to undergo a complex but coordinated sequence of phosphorylation and dephosphorylation events. These studies have contributed significantly to the establishment of protein phosphorylation as a ubiquitous and vital process in signal propagation in neurons, paradigm shifting discoveries at the time. Understanding DA-mediated signaling in the context of signal propagation has led to numerous insights into human conditions and the development of treatments and therapies.
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Affiliation(s)
- Kyle R Christensen
- Department of Psychiatry, Yale University, School of Medicine, New Haven, CT, United States
| | - Angus C Nairn
- Department of Psychiatry, Yale University, School of Medicine, New Haven, CT, United States.
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12
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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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13
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Moreira S, Osswald M, Ventura G, Gonçalves M, Sunkel CE, Morais-de-Sá E. PP1-Mediated Dephosphorylation of Lgl Controls Apical-basal Polarity. Cell Rep 2020; 26:293-301.e7. [PMID: 30625311 DOI: 10.1016/j.celrep.2018.12.060] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 11/23/2018] [Accepted: 12/13/2018] [Indexed: 12/17/2022] Open
Abstract
Apical-basal polarity is a common trait that underlies epithelial function. Although the asymmetric distribution of cortical polarity proteins works in a functioning equilibrium, it also retains plasticity to accommodate cell division, during which the basolateral determinant Lgl is released from the cortex. Here, we investigated how Lgl restores its cortical localization to maintain the integrity of dividing epithelia. We show that cytoplasmic Lgl is reloaded to the cortex at mitotic exit in Drosophila epithelia. Lgl cortical localization depends on protein phosphatase 1, which dephosphorylates Lgl on the serines phosphorylated by aPKC and Aurora A kinases through a mechanism that relies on the regulatory subunit Sds22 and a PP1-interacting RVxF motif of Lgl. This mechanism maintains epithelial polarity and is of particular importance at mitotic exit to couple Lgl cortical reloading with the polarization of the apical domain. Hence, PP1-mediated dephosphorylation of Lgl preserves the apical-basal organization of proliferative epithelia.
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Affiliation(s)
- Sofia Moreira
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal; Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal
| | - Mariana Osswald
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal; Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal
| | - Guilherme Ventura
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal; Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal
| | - Margarida Gonçalves
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal; Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal
| | - Claudio E Sunkel
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal; Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal
| | - Eurico Morais-de-Sá
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal; Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal.
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14
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Essential role of GEXP15, a specific Protein Phosphatase type 1 partner, in Plasmodium berghei in asexual erythrocytic proliferation and transmission. PLoS Pathog 2019; 15:e1007973. [PMID: 31348803 PMCID: PMC6685639 DOI: 10.1371/journal.ppat.1007973] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 08/07/2019] [Accepted: 07/10/2019] [Indexed: 12/21/2022] Open
Abstract
The essential and distinct functions of Protein Phosphatase type 1 (PP1) catalytic subunit in eukaryotes are exclusively achieved through its interaction with a myriad of regulatory partners. In this work, we report the molecular and functional characterization of Gametocyte EXported Protein 15 (GEXP15), a Plasmodium specific protein, as a regulator of PP1. In vitro interaction studies demonstrated that GEXP15 physically interacts with PP1 through the RVxF binding motif in P. berghei. Functional assays showed that GEXP15 was able to increase PP1 activity and the mutation of the RVxF motif completely abolished this regulation. Immunoprecipitation assays of tagged GEXP15 or PP1 in P. berghei followed by immunoblot or mass spectrometry analyses confirmed their interaction and showed that they are present both in schizont and gametocyte stages in shared protein complexes involved in the spliceosome and proteasome pathways and known to play essential role in parasite development. Phenotypic analysis of viable GEXP15 deficient P. berghei blood parasites showed that they were unable to develop lethal infection in BALB/c mice or to establish experimental cerebral malaria in C57BL/6 mice. Further, although deficient parasites produced gametocytes they did not produce any oocysts/sporozoites indicating a high fitness cost in the mosquito. Global proteomic and phosphoproteomic analyses of GEXP15 deficient schizonts revealed a profound defect with a significant decrease in the abundance and an impact on phosphorylation status of proteins involved in regulation of gene expression or invasion. Moreover, depletion of GEXP15 seemed to impact mainly the abundance of some specific proteins of female gametocytes. Our study provides the first insight into the contribution of a PP1 regulator to Plasmodium virulence and suggests that GEXP15 affects both the asexual and sexual life cycle. In the absence of an effective vaccine and the emerging resistance to artemisinin combination therapy, malaria is still a significant threat to human health. Increasing our understanding of the specific mechanisms of the biology of Plasmodium is essential to propose new strategies to control this infection. Here, we demonstrated that GEXP15, a specific protein in Plasmodium, was able to interact with the Protein Phosphatase 1 and regulate its activity. We showed that both proteins are implicated in common protein complexes involved in the mRNA splicing and proteasome pathways. We reported that the deletion of GEXP15 leads to a loss of parasite virulence during asexual stages and a total abolishment of the capacity of deficient parasites to develop in the mosquito. We also found that this deletion affects both protein phosphorylation status and significantly decreases the expression of essential proteins in schizont and gametocyte stages. This study characterizes for the first time a novel molecular pathway through the control of PP1 by an essential and specific Plasmodium regulator, which may contribute to the discovery of new therapeutic targets to control malaria.
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15
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Wang X, Obeidat M, Li L, Pasarj P, Aburahess S, Holmes CFB, Ballermann BJ. TIMAP inhibits endothelial myosin light chain phosphatase by competing with MYPT1 for the catalytic protein phosphatase 1 subunit PP1cβ. J Biol Chem 2019; 294:13280-13291. [PMID: 31315927 PMCID: PMC6737228 DOI: 10.1074/jbc.ra118.006075] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 06/17/2019] [Indexed: 11/06/2022] Open
Abstract
Transforming growth factor-β membrane associated protein (TIMAP) is an endothelial cell (EC)-predominant PP1 regulatory subunit and a member of the myosin phosphatase target (MYPT) protein family. The MYPTs preferentially bind the catalytic protein phosphatase 1 subunit PP1cβ, forming myosin phosphatase holoenzymes. We investigated whether TIMAP/PP1cβ could also function as a myosin phosphatase. Endogenous PP1cβ, myosin light chain 2 (MLC2), and myosin IIA heavy chain coimmunoprecipitated from EC lysates with endogenous TIMAP, and endogenous MLC2 colocalized with TIMAP in EC projections. Purified recombinant GST-TIMAP interacted directly with purified recombinant His-MLC2. However, TIMAP overexpression in EC enhanced MLC2 phosphorylation, an effect not observed with a TIMAP mutant that does not bind PP1cβ. Conversely, MLC2 phosphorylation was reduced in lung lysates from TIMAP-deficient mice and upon silencing of endogenous TIMAP expression in ECs. Ectopically expressed TIMAP slowed the rate of MLC2 dephosphorylation, an effect requiring TIMAP-PP1cβ interaction. The association of MYPT1 with PP1cβ was profoundly reduced in the presence of excess TIMAP, leading to proteasomal MYPT1 degradation. In the absence of TIMAP, MYPT1-associated PP1cβ readily bound immobilized microcystin-LR, an active-site inhibitor of PP1c. By contrast, TIMAP-associated PP1cβ did not interact with microcystin-LR, indicating that the active site of PP1cβ is blocked when it is bound to TIMAP. Thus, TIMAP inhibits myosin phosphatase activity in ECs by competing with MYPT1 for PP1cβ and blocking the PP1cβ active site.
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Affiliation(s)
- Xin Wang
- Department of Medicine, University of Alberta, Edmonton, Alberta T6G 2G3, Canada
| | - Marya Obeidat
- Department of Medicine, University of Alberta, Edmonton, Alberta T6G 2G3, Canada
| | - Laiji Li
- Department of Medicine, University of Alberta, Edmonton, Alberta T6G 2G3, Canada
| | - Phuwadet Pasarj
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2G3, Canada
| | - Salah Aburahess
- Department of Medicine, University of Alberta, Edmonton, Alberta T6G 2G3, Canada
| | - Charles F B Holmes
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2G3, Canada
| | - Barbara J Ballermann
- Department of Medicine, University of Alberta, Edmonton, Alberta T6G 2G3, Canada.
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16
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Li X, Jin B, Dong Y, Chen X, Tu Z, Gu J. Two of the three Transformer-2 genes are required for ovarian development in Aedes albopictus. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2019; 109:92-105. [PMID: 30914323 PMCID: PMC6636634 DOI: 10.1016/j.ibmb.2019.03.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 03/18/2019] [Accepted: 03/21/2019] [Indexed: 05/23/2023]
Abstract
In Drosophila melanogaster, transformer-2 (tra2) plays an essential role in the sex-specific splicing of doublesex (dsx) and fruitless (fru), two key transcription factor genes that program sexual differentiation and regulate sexual behavior. In the present study, the sequences and expression profiles of three tra2 (Aalbtra2) genes in the Asian tiger mosquito, Aedes albopictus (Ae. albopictus) were characterized. Phylogenetic analysis revealed that these paralogs resulted from two duplication events. The first occurred in the common ancestor of Culicidae, giving rise to the tra2-α and tra2-β clades that are found across divergent mosquito genera, including Aedes, Culex, and Anopheles. The second occurred within the tra2-α clade, giving rise to tra2-γ in Ae. albopictus. In addition to the conserved RNA recognition motif (RRM), arginine-rich/serine-rich regions (RS domains) and a linker region, a glycine-rich region located between the RRM and RS2 was observed in Tra2-α and Tra2-γ of Ae. albopictus that has not yet been described in the Tra2 proteins of dipteran insects. Quantitative real-time PCR detected relatively high levels of transcripts from all three tra2 paralogs in 0-2 h embryos, suggesting maternal deposition of these transcripts. All three Aalbtra2 genes were highly expressed in the ovary, while Aalbtra2-β was also highly expressed in the testis. RNAi-mediated knockdown of any or all Aalbtra2 genes did not result in an obvious switch of the sex-specificity in dsx and fru splicing in the whole-body samples. However, knockdown of transcripts from all three tra2 genes significantly reduced the female isoform of dsx mRNA and increased the male isoform of the dsx mRNA in both the ovary and the fat body in adult females. Furthermore, knockdown of either Aalbtra2-α or Aalbtra2-γ or all three Aalbtra2 led to a decrease in ovariole number and ovary size after a blood meal. Taken together, these results indicate that two of the three tra2 genes affect female ovarian development.
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Affiliation(s)
- Xiaocong Li
- Guangdong Provincial Key Laboratory of Tropical Disease Research, Department of Pathogen Biology, School of Public Health, Southern Medical University, Guangzhou, Guangdong, 510515, China
| | - Binbin Jin
- Guangdong Provincial Key Laboratory of Tropical Disease Research, Department of Pathogen Biology, School of Public Health, Southern Medical University, Guangzhou, Guangdong, 510515, China
| | - Yunqiao Dong
- Reproductive Medical Centre of Guangdong Women and Children Hospital, Guangzhou, Guangdong, 511442, China
| | - Xiaoguang Chen
- Guangdong Provincial Key Laboratory of Tropical Disease Research, Department of Pathogen Biology, School of Public Health, Southern Medical University, Guangzhou, Guangdong, 510515, China.
| | - Zhijian Tu
- Department of Biochemistry, Virginia Tech, Blacksburg, VA, 24060, USA
| | - Jinbao Gu
- Guangdong Provincial Key Laboratory of Tropical Disease Research, Department of Pathogen Biology, School of Public Health, Southern Medical University, Guangzhou, Guangdong, 510515, China.
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17
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Plasmodium pseudo-Tyrosine Kinase-like binds PP1 and SERA5 and is exported to host erythrocytes. Sci Rep 2019; 9:8120. [PMID: 31148576 PMCID: PMC6544628 DOI: 10.1038/s41598-019-44542-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 05/15/2019] [Indexed: 01/13/2023] Open
Abstract
Pseudokinases play key roles in many biological processes but they are poorly understood compared to active kinases. Eight putative pseudokinases have been predicted in Plasmodium species. We selected the unique pseudokinase belonging to tyrosine kinase like (TKL) family for detailed structural and functional analysis in P. falciparum and P. berghei. The primary structure of PfpTKL lacks residues critical for kinase activity, supporting its annotation as a pseudokinase. The recombinant pTKL pseudokinase domain was able to bind ATP, but lacked catalytic activity as predicted. The sterile alpha motif (SAM) and RVxF motifs of PfpTKL were found to interact with the P. falciparum proteins serine repeat antigen 5 (SERA5) and protein phosphatase type 1 (PP1) respectively, suggesting that pTKL has a scaffolding role. Furthermore, we found that PP1c activity in a heterologous model was modulated in an RVxF-dependent manner. During the trophozoite stages, PbpTKL was exported to infected erythrocytes where it formed complexes with proteins involved in cytoskeletal organization or host cell maturation and homeostasis. Finally, genetic analysis demonstrated that viable strains obtained by genomic deletion or knocking down PbpTKL did not affect the course of parasite intra-erythrocytic development or gametocyte emergence, indicating functional redundancy during these parasite stages.
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18
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Vallardi G, Cordeiro MH, Saurin AT. A Kinase-Phosphatase Network that Regulates Kinetochore-Microtubule Attachments and the SAC. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2019; 56:457-484. [PMID: 28840249 DOI: 10.1007/978-3-319-58592-5_19] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The KMN network (for KNL1, MIS12 and NDC80 complexes) is a hub for signalling at the outer kinetochore. It integrates the activities of two kinases (MPS1 and Aurora B) and two phosphatases (PP1 and PP2A-B56) to regulate kinetochore-microtubule attachments and the spindle assembly checkpoint (SAC). We will first discuss each of these enzymes separately, to describe how they are regulated at kinetochores and why this is important for their primary function in controlling either microtubule attachments or the SAC. We will then discuss why inhibiting any one of them individually produces secondary effects on all the others. This cross-talk may help to explain why all enzymes have been linked to both processes, even though the direct evidence suggests they each control only one. This chapter therefore describes how a network of kinases and phosphatases work together to regulate two key mitotic processes.
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Affiliation(s)
- Giulia Vallardi
- Division of Cancer Research, School of Medicine, Jacqui Wood Cancer Centre, Ninewells Hospital and Medical School, University of Dundee, Dundee, DD1 9SY, UK
| | - Marilia Henriques Cordeiro
- Division of Cancer Research, School of Medicine, Jacqui Wood Cancer Centre, Ninewells Hospital and Medical School, University of Dundee, Dundee, DD1 9SY, UK
| | - Adrian Thomas Saurin
- Division of Cancer Research, School of Medicine, Jacqui Wood Cancer Centre, Ninewells Hospital and Medical School, University of Dundee, Dundee, DD1 9SY, UK.
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19
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Addison WN, Pellicelli M, St-Arnaud R. Dephosphorylation of the transcriptional cofactor NACA by the PP1A phosphatase enhances cJUN transcriptional activity and osteoblast differentiation. J Biol Chem 2019; 294:8184-8196. [PMID: 30948508 DOI: 10.1074/jbc.ra118.006920] [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: 11/29/2018] [Revised: 04/01/2019] [Indexed: 12/19/2022] Open
Abstract
The transcriptional cofactor nascent polypeptide-associated complex and co-regulator α (NACA) regulates osteoblast maturation and activity. NACA functions, at least in part, by binding to Jun proto-oncogene, AP-1 transcription factor subunit (cJUN) and potentiating the transactivation of AP-1 targets such as osteocalcin (Bglap) and matrix metallopeptidase 9 (Mmp9). NACA activity is modulated by phosphorylation carried out by several kinases, but a phosphatase regulating NACA's activity remains to be identified. Here, we used affinity purification with MS in HEK293T cells to isolate NACA complexes and identified protein phosphatase 1 catalytic subunit α (PP1A) as a NACA-associated Ser/Thr phosphatase. NACA interacted with multiple components of the PP1A holoenzyme complex: the PPP1CA catalytic subunit and the regulatory subunits PPP1R9B, PPP1R12A and PPP1R18. MS analysis revealed that NACA co-expression with PPP1CA causes dephosphorylation of NACA at Thr-89, Ser-151, and Thr-174. NACA Ser/Thr-to-alanine variants displayed increased nuclear localization, and NACA dephosphorylation was associated with specific recruitment of novel NACA interactants, such as basic transcription factor 3 (BTF3) and its homolog BTF3L4. NACA and PP1A cooperatively potentiated cJUN transcriptional activity of the AP-1-responsive MMP9-luciferase reporter, which was abolished when Thr-89, Ser-151, or Thr-174 were substituted with phosphomimetic aspartate residues. We confirmed the NACA-PP1A interaction in MC3T3-E1 osteoblastic cells and observed that NACA phosphorylation status at PP1A-sensitive sites is important for the regulation of AP-1 pathway genes and for osteogenic differentiation and matrix mineralization. These results suggest that PP1A dephosphorylates NACA at specific residues, impacting cJUN transcriptional activity and osteoblast differentiation and function.
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Affiliation(s)
| | | | - René St-Arnaud
- Shriners Hospitals for Children-Canada, Montreal, Quebec, Canada; Department of Human Genetics, McGill University, Montreal, Quebec, Canada; Department of Surgery, McGill University, Montreal, Quebec, Canada; Department of Medicine, McGill University, Montreal, Quebec, Canada; Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada.
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20
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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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21
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Nilsson J. Protein phosphatases in the regulation of mitosis. J Cell Biol 2018; 218:395-409. [PMID: 30446607 PMCID: PMC6363451 DOI: 10.1083/jcb.201809138] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 10/29/2018] [Accepted: 10/29/2018] [Indexed: 12/15/2022] Open
Abstract
The accurate segregation of genetic material to daughter cells during mitosis depends on the precise coordination and regulation of hundreds of proteins by dynamic phosphorylation. Mitotic kinases are major regulators of protein function, but equally important are protein phosphatases that balance their actions, their coordinated activity being essential for accurate chromosome segregation. Phosphoprotein phosphatases (PPPs) that dephosphorylate phosphoserine and phosphothreonine residues are increasingly understood as essential regulators of mitosis. In contrast to kinases, the lack of a pronounced peptide-binding cleft on the catalytic subunit of PPPs suggests that these enzymes are unlikely to be specific. However, recent exciting insights into how mitotic PPPs recognize specific substrates have revealed that they are as specific as kinases. Furthermore, the activities of PPPs are tightly controlled at many levels to ensure that they are active only at the proper time and place. Here, I will discuss substrate selection and regulation of mitotic PPPs focusing mainly on animal cells and explore how these actions control mitosis, as well as important unanswered questions.
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Affiliation(s)
- Jakob Nilsson
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
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22
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Dillon J, Holden-Dye L, O'Connor V. Yeast two-hybrid screening identifies MPZ-1 and PTP-1 as candidate scaffolding proteins of metabotropic glutamate receptors in Caenorhabditis elegans. INVERTEBRATE NEUROSCIENCE 2018; 18:16. [PMID: 30417267 DOI: 10.1007/s10158-018-0218-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 10/19/2018] [Indexed: 10/27/2022]
Abstract
The metabotropic glutamate receptors (mGluRs) are a class of G-protein-coupled receptor that undergo extensive interactions with scaffolding proteins, and this is intrinsic to their function as an important group of neuromodulators at glutamatergic synapses. The Caenorhabditis elegans nervous system expresses three metabotropic glutamate receptors, MGL-1, MGL-2 and MGL-3. Relatively little is known about how the function and signalling of these receptors is organised in C. elegans. To identify proteins that scaffold the MGL-1 receptor, we have conducted a yeast two-hybrid screen. Three of the interacting proteins, MPZ-1, NRFL-1 and PTP-1, displayed motifs characteristic of mammalian mGluR scaffolding proteins. Using cellular co-expression criterion, we show mpz-1 and ptp-1 exhibited overlapping expression patterns with subsets of mgl-1 neurons. This included neurones in the pharyngeal nervous system that control the feeding organ of the worm. The mGluR agonist L-CCG-I inhibits the activity of this network in wild-type worms, in an MGL-1 and dose-dependent manner. We utilised L-CCG-I to identify if MGL-1 function was disrupted in mutants with deletions in the mpz-1 gene. The mpz-1 mutants displayed a largely wild-type response to L-CCG-I, suggesting MGL-1 signalling is not overtly disrupted consistent with a non-obligatory modulatory function in receptor scaffolding. The selectivity of the protein interactions and overlapping expression identified here warrant further investigation of the functional significance of scaffolding of metabotropic glutamate receptor function.
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Affiliation(s)
- James Dillon
- Biological Sciences, University of Southampton, Southampton, SO17 1BJ, UK.
| | - Lindy Holden-Dye
- Biological Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - Vincent O'Connor
- Biological Sciences, University of Southampton, Southampton, SO17 1BJ, UK
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23
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Nasa I, Rusin SF, Kettenbach AN, Moorhead GB. Aurora B opposes PP1 function in mitosis by phosphorylating the conserved PP1-binding RVxF motif in PP1 regulatory proteins. Sci Signal 2018; 11:11/530/eaai8669. [PMID: 29764992 DOI: 10.1126/scisignal.aai8669] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Protein phosphatase 1 (PP1) is a highly conserved protein phosphatase that performs most of the serine- and threonine-dephosphorylation reactions in eukaryotes and opposes the actions of a diverse set of serine and threonine (Ser-Thr) protein kinases. PP1 gains substrate specificity through binding to a large number (>200) of regulatory proteins that control PP1 localization, activity, and interactions with substrates. PP1 recognizes the well-characterized RVxF binding motif that is present in many of these regulatory proteins, thus generating a multitude of distinct PP1 holoenzymes. We showed that a subset of the RVxF binding motifs, in which x is a phosphorylatable amino acid (RV[S/T]F), was phosphorylated specifically during mitosis and that this phosphorylation event abrogated the interaction of PP1 with the regulatory protein. We determined that this phosphorylation was primarily governed by the mitotic protein kinase Aurora B and that high phosphorylation site stoichiometry of these sites maintained the phosphorylation of PP1 substrates during mitosis by disrupting the assembly of PP1 holoenzymes. We generated an antibody that recognizes the phosphorylated form of the RV[S/T]F motif (RVp[S/T]F) and used it to identify known PP1 regulatory proteins (KNL1, CDCA2, and RIF1) and multiple proteins that could potentially act as PP1 binding partners (UBR5, ASPM, SEH1, and ELYS) governed by this mechanism. Together, these data suggest a general regulatory mechanism by which the coordinated activities of Aurora B and PP1 control mitotic progression.
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Affiliation(s)
- Isha Nasa
- Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Scott F Rusin
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Arminja N Kettenbach
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA. .,Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, NH 03756, USA
| | - Greg B Moorhead
- Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada.
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24
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Köhn M. Miklós Bodanszky Award Lecture: Advances in the selective targeting of protein phosphatase-1 and phosphatase-2A with peptides. J Pept Sci 2018; 23:749-756. [PMID: 28876538 PMCID: PMC5639349 DOI: 10.1002/psc.3033] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 07/20/2017] [Accepted: 07/23/2017] [Indexed: 12/13/2022]
Abstract
Protein phosphatase-1 and phosphatase-2A are two ubiquitously expressed enzymes known to catalyze the majority of dephosphorylation reactions on serine and threonine inside cells. They play roles in most cellular processes and are tightly regulated by regulatory subunits in holoenzymes. Their misregulation and malfunction contribute to disease development and progression, such as in cancer, diabetes, viral infections, and neurological as well as heart diseases. Therefore, targeting these phosphatases for therapeutic use would be highly desirable; however, their complex regulation and high conservation of the active site have been major hurdles for selectively targeting them in the past. In the last decade, new approaches have been developed to overcome these hurdles and have strongly revived the field. I will focus here on peptide-based approaches, which contributed to showing that these phosphatases can be targeted selectively and aided in rethinking the design of selective phosphatase modulators. Finally, I will give a perspective on www.depod.org, the human dephosphorylation database, and how it can aid phosphatase modulator design. © 2017 The Authors. Journal of Peptide Science published by European Peptide Society and John Wiley & Sons Ltd.
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Affiliation(s)
- Maja Köhn
- Centre for Biological Signalling Studies (BIOSS), University of Freiburg, Schänzlestraße 18, 79104, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Schänzlestrasse 1, 79104, Freiburg, Germany
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25
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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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The Toxoplasma gondii inhibitor-2 regulates protein phosphatase 1 activity through multiple motifs. Parasitol Res 2017; 116:2417-2426. [PMID: 28667522 DOI: 10.1007/s00436-017-5543-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 06/21/2017] [Indexed: 10/19/2022]
Abstract
Toxoplasma gondii has a complex life cycle characterized by multiple differentiation steps that are essential for its survival in both human and definitive feline host. Several studies have demonstrated the importance of phosphorylations by protein kinases during the life cycle of T. gondii. However, very little is known about protein phosphatases and their regulators in the parasite. We report the molecular and functional characterization of the T. gondii ortholog of the inhibitor-2 protein, designated TgI2. We show that TgI2 encompasses conserved motifs involved in the interaction and modulation of the phosphatase activity of T. gondii protein phosphatase 1, named TgPP1. We show that a specific combination of motifs is involved in binding and/or inhibition of the TgPP1 activity. We show here that the TgI2 protein is a potent inhibitor of TgPP1 phosphatase activity. TgI2 SILK and RVxF motifs are critical for regulating the activity of TgPP1, a feature that is common with the higher eukaryotes inhibitor-2 protein.
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Yadav L, Tamene F, Göös H, van Drogen A, Katainen R, Aebersold R, Gstaiger M, Varjosalo M. Systematic Analysis of Human Protein Phosphatase Interactions and Dynamics. Cell Syst 2017; 4:430-444.e5. [PMID: 28330616 DOI: 10.1016/j.cels.2017.02.011] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 01/10/2017] [Accepted: 02/15/2017] [Indexed: 10/19/2022]
Abstract
Coordinated activities of protein kinases and phosphatases ensure phosphorylation homeostasis, which, when perturbed, can instigate diseases, including cancer. Yet, in contrast to kinases, much less is known about protein phosphatase functions and their interactions and complexes. Here, we used quantitative affinity proteomics to assay protein-protein interactions for 54 phosphatases distributed across the three major protein phosphatase families, with additional analysis of their 12 co-factors. We identified 838 high-confidence interactions, of which 631, to our knowledge, have not been reported before. We show that inhibiting the activity of phosphatases PP1 and PP2A by okadaic acid disrupts their specific interactions, supporting the potential of therapeutics that target these proteins. Additional analyses revealed candidate physical and functional interaction links to phosphatase-based regulation of several signaling pathways and to human cancer. Our study provides an initial glimpse of the protein interaction landscape of phosphatases and their functions in cellular regulation.
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Affiliation(s)
- Leena Yadav
- Institute of Biotechnology, University of Helsinki, Helsinki 00014, Finland
| | - Fitsum Tamene
- Institute of Biotechnology, University of Helsinki, Helsinki 00014, Finland
| | - Helka Göös
- Institute of Biotechnology, University of Helsinki, Helsinki 00014, Finland
| | - Audrey van Drogen
- Institute of Molecular Systems Biology, ETH Zurich, Zurich 8093, Switzerland
| | - Riku Katainen
- Genome-Scale Biology Research Program, Research Programs Unit, University of Helsinki, Helsinki 00014, Finland
| | - Ruedi Aebersold
- Institute of Molecular Systems Biology, ETH Zurich, Zurich 8093, Switzerland
| | - Matthias Gstaiger
- Institute of Molecular Systems Biology, ETH Zurich, Zurich 8093, Switzerland
| | - Markku Varjosalo
- Institute of Biotechnology, University of Helsinki, Helsinki 00014, Finland.
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Chiang DY, Heck AJR, Dobrev D, Wehrens XHT. Regulating the regulator: Insights into the cardiac protein phosphatase 1 interactome. J Mol Cell Cardiol 2016; 101:165-172. [PMID: 27663175 PMCID: PMC5154861 DOI: 10.1016/j.yjmcc.2016.09.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 09/15/2016] [Accepted: 09/18/2016] [Indexed: 11/28/2022]
Abstract
Reversible phosphorylation of proteins is a delicate yet dynamic balancing act between kinases and phosphatases, the disturbance of which underlies numerous disease processes. While our understanding of protein kinases has grown tremendously over the past decades, relatively little is known regarding protein phosphatases. This may be because protein kinases are great in number and relatively specific in function, and thereby amenable to be studied in isolation, whereas protein phosphatases are much less abundant and more nonspecific in their function. To achieve subcellular localization and substrate specificity, phosphatases depend on partnering with a large number of regulatory subunits, protein scaffolds and/or other interactors. This added layer of complexity presents a significant barrier to their study, but holds the key to unexplored opportunities for novel pharmacologic intervention. In this review we focus on serine/threonine protein phosphatase type-1 (PP1), which plays an important role in cardiac physiology and pathophysiology. Although much work has been done to investigate the role of PP1 in cardiac diseases including atrial fibrillation and heart failure, most of these studies were limited to examining and manipulating the catalytic subunit(s) of PP1 without adequately considering the PP1 interactors, which give specificity to PP1's functions. To complement these studies, three unbiased methods have been developed and applied to the mapping of the PP1 interactome: bioinformatics approaches, yeast two-hybrid screens, and affinity-purification mass spectrometry. The application of these complementary methods has the potential to generate a detailed cardiac PP1 interactome, which is an important step in identifying novel and targeted pharmacological interventions.
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Affiliation(s)
- David Y Chiang
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA; Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands; Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Albert J R Heck
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
| | - Dobromir Dobrev
- Institute of Pharmacology, University Duisburg/Essen, Essen, Germany
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA; Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX, USA; Department of Medicine (Cardiology), Baylor College of Medicine, Houston, TX, USA; Department of Pediatrics (Cardiology), Baylor College of Medicine, Houston, TX, USA.
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Duan H, Wang C, Wang M, Gao X, Yan M, Akram S, Peng W, Zou H, Wang D, Zhou J, Chu Y, Dou Z, Barrett G, Green HN, Wang F, Tian R, He P, Wang W, Liu X, Yao X. Phosphorylation of PP1 Regulator Sds22 by PLK1 Ensures Accurate Chromosome Segregation. J Biol Chem 2016; 291:21123-21136. [PMID: 27557660 PMCID: PMC5076521 DOI: 10.1074/jbc.m116.745372] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2016] [Revised: 08/22/2016] [Indexed: 11/06/2022] Open
Abstract
During cell division, accurate chromosome segregation is tightly regulated by Polo-like kinase 1 (PLK1) and opposing activities of Aurora B kinase and protein phosphatase 1 (PP1). However, the regulatory mechanisms underlying the aforementioned hierarchical signaling cascade during mitotic chromosome segregation have remained elusive. Sds22 is a conserved regulator of PP1 activity, but how it regulates PP1 activity in space and time during mitosis remains elusive. Here we show that Sds22 is a novel and cognate substrate of PLK1 in mitosis, and the phosphorylation of Sds22 by PLK1 elicited an inhibition of PP1-mediated dephosphorylation of Aurora B at threonine 232 (Thr232) in a dose-dependent manner. Overexpression of a phosphomimetic mutant of Sds22 causes a dramatic increase in mitotic delay, whereas overexpression of a non-phosphorylatable mutant of Sds22 results in mitotic arrest. Mechanistically, the phosphorylation of Sds22 by PLK1 strengthens the binding of Sds22 to PP1 and inhibits the dephosphorylation of Thr232 of Aurora B to ensure a robust, error-free metaphase-anaphase transition. These findings delineate a conserved signaling hierarchy that orchestrates dynamic protein phosphorylation and dephosphorylation of critical mitotic regulators during chromosome segregation to guard chromosome stability.
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Affiliation(s)
- Hequan Duan
- From the Anhui Key Laboratory for Cellular Dynamics & Chemical Biology, MOE Collaborative Innovation Center of Chemistry for Life Sciences, University of Science & Technology of China, Hefei 230027, China, the Morehouse School of Medicine and Atlanta Clinical & Translational Science Institute, Atlanta, Georgia 30310
| | - Chunli Wang
- the National Chromatographic Research and Analysis Center, Chinesse Academy of Sciences, Dalian 116023, China
| | - Ming Wang
- From the Anhui Key Laboratory for Cellular Dynamics & Chemical Biology, MOE Collaborative Innovation Center of Chemistry for Life Sciences, University of Science & Technology of China, Hefei 230027, China
| | - Xinjiao Gao
- From the Anhui Key Laboratory for Cellular Dynamics & Chemical Biology, MOE Collaborative Innovation Center of Chemistry for Life Sciences, University of Science & Technology of China, Hefei 230027, China
| | - Maomao Yan
- From the Anhui Key Laboratory for Cellular Dynamics & Chemical Biology, MOE Collaborative Innovation Center of Chemistry for Life Sciences, University of Science & Technology of China, Hefei 230027, China
| | - Saima Akram
- From the Anhui Key Laboratory for Cellular Dynamics & Chemical Biology, MOE Collaborative Innovation Center of Chemistry for Life Sciences, University of Science & Technology of China, Hefei 230027, China
| | - Wei Peng
- From the Anhui Key Laboratory for Cellular Dynamics & Chemical Biology, MOE Collaborative Innovation Center of Chemistry for Life Sciences, University of Science & Technology of China, Hefei 230027, China
| | - Hanfa Zou
- the National Chromatographic Research and Analysis Center, Chinesse Academy of Sciences, Dalian 116023, China
| | - Dong Wang
- From the Anhui Key Laboratory for Cellular Dynamics & Chemical Biology, MOE Collaborative Innovation Center of Chemistry for Life Sciences, University of Science & Technology of China, Hefei 230027, China
| | - Jiajia Zhou
- From the Anhui Key Laboratory for Cellular Dynamics & Chemical Biology, MOE Collaborative Innovation Center of Chemistry for Life Sciences, University of Science & Technology of China, Hefei 230027, China
| | - Youjun Chu
- From the Anhui Key Laboratory for Cellular Dynamics & Chemical Biology, MOE Collaborative Innovation Center of Chemistry for Life Sciences, University of Science & Technology of China, Hefei 230027, China, the Morehouse School of Medicine and Atlanta Clinical & Translational Science Institute, Atlanta, Georgia 30310
| | - Zhen Dou
- From the Anhui Key Laboratory for Cellular Dynamics & Chemical Biology, MOE Collaborative Innovation Center of Chemistry for Life Sciences, University of Science & Technology of China, Hefei 230027, China
| | - Gregory Barrett
- the Morehouse School of Medicine and Atlanta Clinical & Translational Science Institute, Atlanta, Georgia 30310
| | - Hadiyah-Nicole Green
- the Morehouse School of Medicine and Atlanta Clinical & Translational Science Institute, Atlanta, Georgia 30310
| | - Fangjun Wang
- the National Chromatographic Research and Analysis Center, Chinesse Academy of Sciences, Dalian 116023, China
| | - Ruijun Tian
- the Guangzhou Women and Children's Medical Center, Guangzhou 510623, China, and the Center of Molecular Proteomics, South University of Science & Technology of China, Shenzhen 518055, China
| | - Ping He
- the Guangzhou Women and Children's Medical Center, Guangzhou 510623, China, and the Center of Molecular Proteomics, South University of Science & Technology of China, Shenzhen 518055, China
| | - Wenwen Wang
- From the Anhui Key Laboratory for Cellular Dynamics & Chemical Biology, MOE Collaborative Innovation Center of Chemistry for Life Sciences, University of Science & Technology of China, Hefei 230027, China, the Morehouse School of Medicine and Atlanta Clinical & Translational Science Institute, Atlanta, Georgia 30310,
| | - Xing Liu
- From the Anhui Key Laboratory for Cellular Dynamics & Chemical Biology, MOE Collaborative Innovation Center of Chemistry for Life Sciences, University of Science & Technology of China, Hefei 230027, China, the Morehouse School of Medicine and Atlanta Clinical & Translational Science Institute, Atlanta, Georgia 30310,
| | - Xuebiao Yao
- From the Anhui Key Laboratory for Cellular Dynamics & Chemical Biology, MOE Collaborative Innovation Center of Chemistry for Life Sciences, University of Science & Technology of China, Hefei 230027, China,
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Analysis of the interactome of the Ser/Thr Protein Phosphatase type 1 in Plasmodium falciparum. BMC Genomics 2016; 17:246. [PMID: 26988354 PMCID: PMC4794898 DOI: 10.1186/s12864-016-2571-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 03/07/2016] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Protein Phosphatase 1 (PP1) is an enzyme essential to cell viability in the malaria parasite Plasmodium falciparum (Pf). The activity of PP1 is regulated by the binding of regulatory subunits, of which there are up to 200 in humans, but only 3 have been so far reported for the parasite. To better understand the P. falciparum PP1 (PfPP1) regulatory network, we here report the use of three strategies to characterize the PfPP1 interactome: co-affinity purified proteins identified by mass spectrometry, yeast two-hybrid (Y2H) screening and in silico analysis of the P. falciparum predicted proteome. RESULTS Co-affinity purification followed by MS analysis identified 6 PfPP1 interacting proteins (Pips) of which 3 contained the RVxF consensus binding, 2 with a Fxx[RK]x[RK] motif, also shown to be a PP1 binding motif and one with both binding motifs. The Y2H screens identified 134 proteins of which 30 present the RVxF binding motif and 20 have the Fxx[RK]x[RK] binding motif. The in silico screen of the Pf predicted proteome using a consensus RVxF motif as template revealed the presence of 55 potential Pips. As further demonstration, 35 candidate proteins were validated as PfPP1 interacting proteins in an ELISA-based assay. CONCLUSIONS To the best of our knowledge, this is the first study on PfPP1 interactome. The data reports several conserved PP1 interacting proteins as well as a high number of specific interactors to PfPP1. Their analysis indicates a high diversity of biological functions for PP1 in Plasmodium. Based on the present data and on an earlier study of the Pf interactome, a potential implication of Pips in protein folding/proteolysis, transcription and pathogenicity networks is proposed. The present work provides a starting point for further studies on the structural basis of these interactions and their functions in P. falciparum.
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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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Wesselborg S, Stork B. Autophagy signal transduction by ATG proteins: from hierarchies to networks. Cell Mol Life Sci 2015; 72:4721-57. [PMID: 26390974 PMCID: PMC4648967 DOI: 10.1007/s00018-015-2034-8] [Citation(s) in RCA: 165] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 08/13/2015] [Accepted: 08/31/2015] [Indexed: 02/07/2023]
Abstract
Autophagy represents an intracellular degradation process which is involved in both cellular homeostasis and disease settings. In the last two decades, the molecular machinery governing this process has been characterized in detail. To date, several key factors regulating this intracellular degradation process have been identified. The so-called autophagy-related (ATG) genes and proteins are central to this process. However, several additional molecules contribute to the outcome of an autophagic response. Several review articles describing the molecular process of autophagy have been published in the recent past. In this review article we would like to add the most recent findings to this knowledge, and to give an overview of the network character of the autophagy signaling machinery.
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Affiliation(s)
- Sebastian Wesselborg
- Institute of Molecular Medicine I, Heinrich-Heine-University, Universitätsstr. 1, Building 23.12, 40225, Düsseldorf, Germany
| | - Björn Stork
- Institute of Molecular Medicine I, Heinrich-Heine-University, Universitätsstr. 1, Building 23.12, 40225, Düsseldorf, Germany.
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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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34
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Silva JV, Freitas MJ, Felgueiras J, Fardilha M. The power of the yeast two-hybrid system in the identification of novel drug targets: building and modulating PPP1 interactomes. Expert Rev Proteomics 2015; 12:147-58. [PMID: 25795147 DOI: 10.1586/14789450.2015.1024226] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Since the description of the yeast two-hybrid (Y2H) method, it has become more and more evident that it is the most commonly used method to identify protein-protein interactions (PPIs). The improvements in the original Y2H methodology in parallel with the idea that PPIs are promising drug targets, offer an excellent opportunity to apply the principles of this molecular biology technique to the pharmaceutical field. Additionally, the theoretical developments in the networks field make PPI networks very useful frameworks that facilitate many discoveries in biomedicine. This review highlights the relevance of Y2H in the determination of PPIs, specifically phosphoprotein phosphatase 1 interactions, and its possible outcomes in pharmaceutical research.
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Affiliation(s)
- Joana Vieira Silva
- Signal Transduction Laboratory, Institute for Research in Biomedicine - iBiMED, Health Sciences Program, University of Aveiro, Aveiro, Portugal
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35
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Martins F, Rebelo S, Santos M, Cotrim CZ, da Cruz e Silva EF, da Cruz e Silva OAB. BRI2 and BRI3 are functionally distinct phosphoproteins. Cell Signal 2015; 28:130-44. [PMID: 26515131 DOI: 10.1016/j.cellsig.2015.10.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 10/24/2015] [Indexed: 01/21/2023]
Abstract
Three BRI protein family members have been identified. Among these are BRI3 and BRI2, the latter is associated with Familial Danish and Familial British dementias. 'In silico' sequence analysis identified putative PP1 binding sites in BRI2 and BRI3. This is singularly important, given that protein phosphorylation is a major mechanism regulating intracellular processes. Protein phosphatase 1 (PP1) interacting proteins (PIPs) are fundamental in determining substrate specificity and subcellular localization of this phosphatase. More than 200 PIPs have thus far been reported. Both BRI2 and BRI3 are type II transmembrane glycoproteins relevant in neuronal systems. Using Myc-BRI2 and Myc-BRI3, wild type and PP1 binding mutant constructs, it was possible to show, for the first time, that in fact BRI2 and BRI3 bind PP1. The complexes BRI2:PP1 and BRI3:PP1 were validated in vitro and in vivo. The subcellular distribution of BRI2 and BRI3 is similar; both localize to the perinuclear area and Golgi apparatus in non-neuronal cells. However, in SH-SY5Y cells, BRI2 and BRI3 could also be detected in elongated cellular projections ('processes') and in rat cortical neurons both are broadly distributed throughout the cell body, neuritis and the nucleus. Consistently, co-localization of BRI2 and BRI3 with PP1 was evident. The functional significance of these complexes is apparent given that both BRI proteins are substrates of PP1, thus simultaneously this is the first report of BRI2 and BRI3 as phosphoproteins. Moreover, we show that when BRI2 is phosphorylated a significant increase in neuronal outgrowth and differentiation is evident. Interestingly, the Alzheimer's amyloid precursor protein (APP), forms a trimeric complex composed of PP1 and Fe65, with PP1 having the capacity to dephosphorylate APP at Thr668 residue. The emerging consensus appears to be that PP1 containing complexes are crucial in regulating signaling events underlying neuropathological conditions.
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Affiliation(s)
- Filipa Martins
- Laboratório de Neurociências e Sinalização Celular, Centro de Biologia Celular, iBiMED, SACS, Universidade de Aveiro, Aveiro, Portugal
| | - Sandra Rebelo
- Laboratório de Neurociências e Sinalização Celular, Centro de Biologia Celular, iBiMED, SACS, Universidade de Aveiro, Aveiro, Portugal.
| | - Mariana Santos
- Laboratório de Neurociências e Sinalização Celular, Centro de Biologia Celular, iBiMED, SACS, Universidade de Aveiro, Aveiro, Portugal
| | - Cândida Zita Cotrim
- Laboratório de Neurociências e Sinalização Celular, Centro de Biologia Celular, iBiMED, SACS, Universidade de Aveiro, Aveiro, Portugal
| | - Edgar F da Cruz e Silva
- Laboratório de Neurociências e Sinalização Celular, Centro de Biologia Celular, iBiMED, SACS, Universidade de Aveiro, Aveiro, Portugal
| | - Odete A B da Cruz e Silva
- Laboratório de Neurociências e Sinalização Celular, Centro de Biologia Celular, iBiMED, SACS, Universidade de Aveiro, Aveiro, Portugal
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Felgueiras J, Fardilha M. Phosphoprotein phosphatase 1-interacting proteins as therapeutic targets in prostate cancer. World J Pharmacol 2014; 3:120-139. [DOI: 10.5497/wjp.v3.i4.120] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2014] [Revised: 09/01/2014] [Accepted: 09/24/2014] [Indexed: 02/06/2023] Open
Abstract
Prostate cancer is a major public health concern worldwide, being one of the most prevalent cancers in men. Great improvements have been made both in terms of early diagnosis and therapeutics. However, there is still an urgent need for reliable biomarkers that could overcome the lack of cancer-specificity of prostate-specific antigen, as well as alternative therapeutic targets for advanced metastatic cases. Reversible phosphorylation of proteins is a post-translational modification critical to the regulation of numerous cellular processes. Phosphoprotein phosphatase 1 (PPP1) is a major serine/threonine phosphatase, whose specificity is determined by its interacting proteins. These interactors can be PPP1 substrates, regulators, or even both. Deregulation of this protein-protein interaction network alters cell dynamics and underlies the development of several cancer hallmarks. Therefore, the identification of PPP1 interactome in specific cellular context is of crucial importance. The knowledge on PPP1 complexes in prostate cancer remains scarce, with only 4 holoenzymes characterized in human prostate cancer models. However, an increasing number of PPP1 interactors have been identified as expressed in human prostate tissue, including the tumor suppressors TP53 and RB1. Efforts should be made in order to identify the role of such proteins in prostate carcinogenesis, since only 26 have yet well-recognized roles. Here, we revise literature and human protein databases to provide an in-depth knowledge on the biological significance of PPP1 complexes in human prostate carcinogenesis and their potential use as therapeutic targets for the development of new therapies for prostate cancer.
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Lee KY, Bae JS, Yoon S, Hwang DS. Dephosphorylation of Orc2 by protein phosphatase 1 promotes the binding of the origin recognition complex to chromatin. Biochem Biophys Res Commun 2014; 448:385-9. [PMID: 24792176 DOI: 10.1016/j.bbrc.2014.04.109] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 04/22/2014] [Indexed: 01/21/2023]
Abstract
Phosphorylation of Orc2, one of the six subunits of the origin recognition complex (ORC), by cyclin A/CDK2 during S phase leads to the dissociation of Orc2, Orc3, Orc4, and Orc5 subunits (Orc2-5) from human chromatin and replication origins. Dephosphorylation of the phosphorylated Orc2 by protein phosphatase 1 (PP1) is accompanied by the binding of the dissociated subunits to chromatin. Here we show that PP1 physically interacts with Orc2. The binding of PP1 to Orc2 and the dephosphorylation of Orc2 by PP1 occurred in a cell cycle-dependent manner through an interaction with 119-KSVSF-123, which is the consensus motif for the binding of PP1, of Orc2. The dephosphorylation of Orc2 by PP1 is required for the binding of Orc2 to chromatin. These results support that PP1 dephosphorylates Orc2 to promote the binding of ORC to chromatin and replication origins for the subsequent round of the cell cycle.
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Affiliation(s)
- Kyung Yong Lee
- Department of Biological Sciences, Seoul National University, Seoul 151-742, Republic of Korea
| | - June Sung Bae
- Department of Biological Sciences, Seoul National University, Seoul 151-742, Republic of Korea
| | - Sangwook Yoon
- Department of Biological Sciences, Seoul National University, Seoul 151-742, Republic of Korea
| | - Deog Su Hwang
- Department of Biological Sciences, Seoul National University, Seoul 151-742, Republic of Korea.
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Protein phosphatase PP1/GLC7 interaction domain in yeast eIF2γ bypasses targeting subunit requirement for eIF2α dephosphorylation. Proc Natl Acad Sci U S A 2014; 111:E1344-53. [PMID: 24706853 DOI: 10.1073/pnas.1400129111] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Whereas the protein kinases GCN2, HRI, PKR, and PERK specifically phosphorylate eukaryotic translation initiation factor 2 (eIF2α) on Ser51 to regulate global and gene-specific mRNA translation, eIF2α is dephosphorylated by the broadly acting serine/threonine protein phosphatase 1 (PP1). In mammalian cells, the regulatory subunits GADD34 and CReP target PP1 to dephosphorylate eIF2α; however, as there are no homologs of these targeting subunits in yeast, it is unclear how GLC7, the functional homolog of PP1 in yeast, is recruited to dephosphorylate eIF2α. Here, we show that a novel N-terminal extension on yeast eIF2γ contains a PP1-binding motif (KKVAF) that enables eIF2γ to pull down GLC7 and target it to dephosphorylate eIF2α. Truncation or point mutations designed to eliminate the KKVAF motif in eIF2γ impair eIF2α dephosphorylation in vivo and in vitro and enhance expression of GCN4. Replacement of the N terminus of eIF2γ with the GLC7-binding domain from GAC1 or fusion of heterologous dimerization domains to eIF2γ and GLC7, respectively, maintained eIF2α phosphorylation at basal levels. Taken together, these results indicate that, in contrast to the paradigm of distinct PP1-targeting or regulatory subunits, the unique N terminus of yeast eIF2γ functions in cis to target GLC7 to dephosphorylate eIF2α.
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Korrodi-Gregório L, Margarida Lopes A, Esteves SLC, Afonso S, Lemos de Matos A, Lissovsky AA, da Cruz e Silva OAB, da Cruz e Silva EF, Esteves PJ, Fardilha M. An intriguing shift occurs in the novel protein phosphatase 1 binding partner, TCTEX1D4: evidence of positive selection in a pika model. PLoS One 2013; 8:e77236. [PMID: 24130861 PMCID: PMC3795061 DOI: 10.1371/journal.pone.0077236] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 09/01/2013] [Indexed: 12/21/2022] Open
Abstract
T-complex testis expressed protein 1 domain containing 4 (TCTEX1D4) contains the canonical phosphoprotein phosphatase 1 (PPP1) binding motif, composed by the amino acid sequence RVSF. We identified and validated the binding of TCTEX1D4 to PPP1 and demonstrated that indeed this protein is a novel PPP1 interacting protein. Analyses of twenty-one mammalian species available in public databases and seven Lagomorpha sequences obtained in this work showed that the PPP1 binding motif 90RVSF93 is present in all of them and is flanked by a palindromic sequence, PLGS, except in three species of pikas (Ochotona princeps, O. dauurica and O. pusilla). Furthermore, for the Ochotona species an extra glycosylation site, motif 96NLS98, and the loss of the palindromic sequence were observed. Comparison with other lagomorphs suggests that this event happened before the Ochotona radiation. The dN/dS for the sequence region comprising the PPP1 binding motif and the flanking palindrome highly supports the hypothesis that for Ochotona species this region has been evolving under positive selection. In addition, mutational screening shows that the ability of pikas TCTEX1D4 to bind to PPP1 is maintained, although the PPP1 binding motif is disrupted, and the N- and C-terminal surrounding residues are also abrogated. These observations suggest pika as an ideal model to study novel PPP1 complexes regulatory mechanisms.
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Affiliation(s)
- Luís Korrodi-Gregório
- Laboratory of Signal Transduction, Centre for Cell Biology, Health Sciences Department and Biology Department, University of Aveiro, Aveiro, Portugal
| | - Ana Margarida Lopes
- CIBIO/UP, Centro de Investigação em Biodiversidade e Recursos Genéticos/Universidade do Porto, InBio, Laboratório Associado, Vairão, Portugal
- Departamento de Zoologia e Antropologia, Faculdade de Ciências da Universidade do Porto, Porto, Portugal
- INSERM, Institut National de la Santé et de la Recherche Médicale, Unit 892, Université de Nantes, Nantes, France
| | - Sara L. C. Esteves
- Laboratory of Signal Transduction, Centre for Cell Biology, Health Sciences Department and Biology Department, University of Aveiro, Aveiro, Portugal
| | - Sandra Afonso
- CIBIO/UP, Centro de Investigação em Biodiversidade e Recursos Genéticos/Universidade do Porto, InBio, Laboratório Associado, Vairão, Portugal
| | - Ana Lemos de Matos
- CIBIO/UP, Centro de Investigação em Biodiversidade e Recursos Genéticos/Universidade do Porto, InBio, Laboratório Associado, Vairão, Portugal
- Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois, United States of America
| | | | - Odete A. B. da Cruz e Silva
- Laboratory of Neurosciences, Centre for Cell Biology, Health Sciences Department and Biology Department, University of Aveiro, Aveiro, Portugal
| | - Edgar F. da Cruz e Silva
- Laboratory of Signal Transduction, Centre for Cell Biology, Health Sciences Department and Biology Department, University of Aveiro, Aveiro, Portugal
| | - Pedro José Esteves
- CIBIO/UP, Centro de Investigação em Biodiversidade e Recursos Genéticos/Universidade do Porto, InBio, Laboratório Associado, Vairão, Portugal
- CESPU, Instituto de Investigação e Formação Avançada em Ciências e Tecnologias da Saúde, Gandra PRD, Portugal
- * E-mail: (MF); (PJE)
| | - Margarida Fardilha
- Laboratory of Signal Transduction, Centre for Cell Biology, Health Sciences Department and Biology Department, University of Aveiro, Aveiro, Portugal
- * E-mail: (MF); (PJE)
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Santos M, Rebelo S, Van Kleeff PJM, Kim CE, Dauer WT, Fardilha M, da Cruz e Silva OA, da Cruz e Silva EF. The nuclear envelope protein, LAP1B, is a novel protein phosphatase 1 substrate. PLoS One 2013; 8:e76788. [PMID: 24116158 PMCID: PMC3792071 DOI: 10.1371/journal.pone.0076788] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 09/03/2013] [Indexed: 12/11/2022] Open
Abstract
Protein phosphatase 1 (PP1) binding proteins are quintessential regulators, determining substrate specificity and defining subcellular localization and activity of the latter. Here, we describe a novel PP1 binding protein, the nuclear membrane protein lamina associated polypeptide 1B (LAP1B), which interacts with the DYT1 dystonia protein torsinA. The PP1 binding domain in LAP1B was here identified as the REVRF motif at amino acids 55-59. The LAP1B:PP1 complex can be immunoprecipitated from cells in culture and rat cortex and the complex was further validated by yeast co-transformations and blot overlay assays. PP1, which is enriched in the nucleus, binds to the N-terminal nuclear domain of LAP1B, as shown by immunocolocalization and domain specific binding studies. PP1 dephosphorylates LAP1B, confirming the physiological relevance of this interaction. These findings place PP1 at a key position to participate in the pathogenesis of DYT1 dystonia and related nuclear envelope-based diseases.
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Affiliation(s)
- Mariana Santos
- Health Sciences Department, Centre for Cell Biology, Neuroscience Laboratory, University of Aveiro, Aveiro, Portugal
| | - Sandra Rebelo
- Health Sciences Department, Centre for Cell Biology, Neuroscience Laboratory, University of Aveiro, Aveiro, Portugal
| | - Paula J. M. Van Kleeff
- Health Sciences Department, Centre for Cell Biology, Signal Transduction Laboratory, University of Aveiro, Aveiro, Portugal
| | - Connie E. Kim
- Departments of Neurology and Cell & Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - William T. Dauer
- Departments of Neurology and Cell & Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Margarida Fardilha
- Health Sciences Department, Centre for Cell Biology, Signal Transduction Laboratory, University of Aveiro, Aveiro, Portugal
| | - Odete A. da Cruz e Silva
- Health Sciences Department, Centre for Cell Biology, Neuroscience Laboratory, University of Aveiro, Aveiro, Portugal
| | - Edgar F. da Cruz e Silva
- Health Sciences Department, Centre for Cell Biology, Signal Transduction Laboratory, University of Aveiro, Aveiro, Portugal
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Abstract
PP1 (protein phosphatase 1) is an essential serine/threonine phosphatase that plays a critical role in a broad range of biological processes, from muscle contraction to memory formation. PP1 achieves its biological specificity by forming holoenzymes with more than 200 known regulatory proteins. Interestingly, most of these regulatory proteins (≥ 70%) belong to the class of IDPs (intrinsically disordered proteins). Thus structural studies highlighting the interaction of these IDP regulatory proteins with PP1 are an attractive model system because it allows general parameters for a group of diverse IDPs that interact with the same binding partner to be identified, while also providing fundamental insights into PP1 biology. The present review provides a brief overview of our current understanding of IDP-PP1 interactions, including the importance of pre-formed secondary and tertiary structures for PP1 binding, as well as changes of IDP dynamics upon interacting with PP1.
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Wong PM, Puente C, Ganley IG, Jiang X. The ULK1 complex: sensing nutrient signals for autophagy activation. Autophagy 2013; 9:124-37. [PMID: 23295650 PMCID: PMC3552878 DOI: 10.4161/auto.23323] [Citation(s) in RCA: 365] [Impact Index Per Article: 33.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The Atg1/ULK1 complex plays a central role in starvation-induced autophagy, integrating signals from upstream sensors such as MTOR and AMPK and transducing them to the downstream autophagy pathway. Much progress has been made in the last few years in understanding the mechanisms by which the complex is regulated through protein-protein interactions and post-translational modifications, providing insights into how the cell modulates autophagy, particularly in response to nutrient status. However, how the ULK1 complex transduces upstream signals to the downstream central autophagy pathway is still unclear. Although the protein kinase activity of ULK1 is required for its autophagic function, its protein substrate(s) responsible for autophagy activation has not been identified. Furthermore, examples of potential ULK1-independent autophagy have emerged, indicating that under certain specific contexts, the ULK1 complex might be dispensable for autophagy activation. This raises the question of how the autophagic machinery is activated independent of the ULK1 complex and what are the biological functions of such noncanonical autophagy pathways.
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Affiliation(s)
- Pui-Mun Wong
- Cell Biology Program; Memorial Sloan-Kettering Cancer Center; New York, NY USA
| | - Cindy Puente
- Cell Biology Program; Memorial Sloan-Kettering Cancer Center; New York, NY USA
| | - Ian G. Ganley
- MRC Protein Phosphorylation Unit; University of Dundee; Dundee, Scotland UK
| | - Xuejun Jiang
- Cell Biology Program; Memorial Sloan-Kettering Cancer Center; New York, NY USA
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43
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Kassler K, Sticht H. Molecular mechanism of HIV-1 gp120 mutations that reduce CD4 binding affinity. J Biomol Struct Dyn 2013; 32:52-64. [DOI: 10.1080/07391102.2012.746946] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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44
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Boens S, Szekér K, Van Eynde A, Bollen M. Interactor-guided dephosphorylation by protein phosphatase-1. Methods Mol Biol 2013; 1053:271-281. [PMID: 23860659 DOI: 10.1007/978-1-62703-562-0_16] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Protein phosphatase-1 (PP1) is an essential enzyme for every eukaryotic cell and catalyzes more than half of all protein dephosphorylations at serine and threonine residues. The free catalytic subunit of PP1 shows little substrate selectivity but is tightly regulated in vivo by a large variety of structurally unrelated PP1-interacting proteins (PIPs). PIPs form highly specific dimeric or trimeric PP1 holoenzymes by acting as substrates, inhibitors, and/or substrate-specifiers. The surface of PP1 contains many binding sites for short PP1-docking motifs that are combined by PIPs to create a PP1-binding code that is universal, specific, degenerate, nonexclusive, and dynamic. These properties of the PP1-binding code can be used for the rational design of small molecules that disrupt subsets of PP1 holoenzymes and have a therapeutic potential.
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Affiliation(s)
- Shannah Boens
- Laboratory of Biosignaling & Therapeutics, Department of Cellular and Molecular Medicine, University of Leuven, Leuven, Belgium
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45
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Seebahn A, Sticht H, Enz R. Expression, purification, and structural analysis of intracellular C-termini from metabotropic glutamate receptors. Methods Enzymol 2013; 520:257-79. [PMID: 23332704 DOI: 10.1016/b978-0-12-391861-1.00012-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Glutamate is the most important excitatory neurotransmitter in the mammalian central nervous system (CNS). Metabotropic glutamate receptors (mGluRs) are G-protein-coupled receptors (GPCRs) that guide several intracellular signal cascades thereby controlling multiple physiological tasks, such as neuronal excitability, learning, and memory. Consequently, these receptors are discussed in the context of several CNS-associated diseases, including addiction for drugs, Alzheimer's disease, Fragile X syndrome, night blindness, or schizophrenia. Although increasing structural information is available for the extracellular and transmembrane domains of GPCRs, data describing the nature of intracellular receptor domains are largely missing. Indeed, in all available crystal structures of neurotransmitter receptors, their intracellular domains were omitted. Most intracellular mGluR C-termini are alternatively spliced and contain multiple binding sites for interacting proteins. Therefore, analyzing their structure can identify molecular mechanisms of receptor regulation. Recently, we analyzed the conformation of the intracellular C-termini of mGluR6, mGluR7a, and mGluR8a. Here, we describe an array of biochemical, biophysical, and computational techniques suited to elucidate the nature of these highly interesting receptor domains.
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Affiliation(s)
- Angela Seebahn
- Institut für Biochemie (Emil-Fischer-Zentrum), Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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46
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Marquina M, Queralt E, Casamayor A, Ariño J. Lack of the Glc7 phosphatase regulatory subunit Ypi1 activates the morphogenetic checkpoint. Int J Biochem Cell Biol 2012; 44:1862-71. [DOI: 10.1016/j.biocel.2012.06.029] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Revised: 06/15/2012] [Accepted: 06/19/2012] [Indexed: 10/28/2022]
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47
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Meier J, Kassler K, Sticht H, Eichler J. Peptides presenting the binding site of human CD4 for the HIV-1 envelope glycoprotein gp120. Beilstein J Org Chem 2012; 8:1858-66. [PMID: 23209523 PMCID: PMC3511023 DOI: 10.3762/bjoc.8.214] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Accepted: 09/24/2012] [Indexed: 01/31/2023] Open
Abstract
Based on the structure of the HIV-1 glycoprotein gp120 in complex with its cellular receptor CD4, we have designed and synthesized peptides that mimic the binding site of CD4 for gp120. The ability of these peptides to bind to gp120 can be strongly enhanced by increasing their conformational stability through cyclization, as evidenced by binding assays, as well as through molecular-dynamics simulations of peptide–gp120 complexes. The specificity of the peptide–gp120 interaction was demonstrated by using peptide variants, in which key residues for the interaction with gp120 were replaced by alanine or D-amino acids.
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Affiliation(s)
- Julia Meier
- Department of Chemistry and Pharmacy, Universität Erlangen-Nürnberg, Schuhstrasse 19, 91052 Erlangen, Germany
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48
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Esteves SLC, Korrodi-Gregório L, Cotrim CZ, van Kleeff PJM, Domingues SC, da Cruz e Silva OAB, Fardilha M, da Cruz e Silva EF. Protein phosphatase 1γ isoforms linked interactions in the brain. J Mol Neurosci 2012; 50:179-97. [PMID: 23080069 DOI: 10.1007/s12031-012-9902-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Accepted: 10/03/2012] [Indexed: 01/03/2023]
Abstract
Posttranslational protein modifications, in particular reversible protein phosphorylation, are important regulatory mechanisms involved in cellular signaling transduction pathways. Thousands of human proteins are phosphorylatable and the tight regulation of phosphorylation states is crucial for cell maintenance and development. Protein phosphorylation occurs primarily on serine, threonine, and tyrosine residues, through the antagonistic actions of protein kinases and phosphatases. The catalytic subunit of protein phosphatase 1 (PP1), a major Ser/Thr-phosphatase, associates with a large variety of regulatory subunits that define substrate specificity and determine specific cellular pathway responses. PP1 has been shown to bind to different proteins in the brain in order to execute key and differential functions. This work reports the identification of proteins expressed in the human brain that interact with PP1γ1 and PP1γ2 isoforms by the yeast two-hybrid method. An extensive search of PP1-binding motifs was performed for the proteins identified, revealing already known PP1 regulators but also novel interactors. Moreover, our results were integrated with the data of PP1γ interacting proteins from several public web databases, permitting the development of physical maps of the novel interactions. The PP1γ interactome thus obtained allowed for the identification of novel PP1 interacting proteins, supporting novel functions of PP1γ isoforms in the human brain.
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Affiliation(s)
- Sara L C Esteves
- Signal Transduction Laboratory, Centre for Cell Biology, Biology Department, University of Aveiro, 3810-193 Aveiro, Portugal
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49
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O'Connell N, Nichols SR, Heroes E, Beullens M, Bollen M, Peti W, Page R. The molecular basis for substrate specificity of the nuclear NIPP1:PP1 holoenzyme. Structure 2012; 20:1746-56. [PMID: 22940584 PMCID: PMC3472097 DOI: 10.1016/j.str.2012.08.003] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 08/06/2012] [Accepted: 08/07/2012] [Indexed: 11/18/2022]
Abstract
Regulation of protein phosphatase 1 (PP1) is controlled by a diverse array of regulatory proteins. However, how these proteins direct PP1 specificity is not well understood. More than one-third of the nuclear pool of PP1 forms a holoenzyme with the nuclear inhibitor of PP1, NIPP1, to regulate chromatin remodeling, among other essential biological functions. Here, we show that the PP1-binding domain of NIPP1 is an intrinsically disordered protein, which binds PP1 in an unexpected manner. NIPP1 forms an α helix that engages PP1 at a unique interaction site, using polar rather than hydrophobic contacts. Importantly, the structure also reveals a shared PP1 interaction site outside of the RVxF motif, the ΦΦ motif. Finally, we show that NIPP1:PP1 substrate selectivity is determined by altered electrostatics and enhanced substrate localization. Together, our results provide the molecular basis by which NIPP1 directs PP1 substrate specificity in the nucleus.
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Affiliation(s)
- Nichole O'Connell
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, Providence, RI 02912, USA
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50
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Enz R. Structure of metabotropic glutamate receptor C-terminal domains in contact with interacting proteins. Front Mol Neurosci 2012; 5:52. [PMID: 22536173 PMCID: PMC3332230 DOI: 10.3389/fnmol.2012.00052] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Accepted: 04/02/2012] [Indexed: 01/22/2023] Open
Abstract
Metabotropic glutamate receptors (mGluRs) regulate intracellular signal pathways that control several physiological tasks, including neuronal excitability, learning, and memory. This is achieved by the formation of synaptic signal complexes, in which mGluRs assemble with functionally related proteins such as enzymes, scaffolds, and cytoskeletal anchor proteins. Thus, mGluR associated proteins actively participate in the regulation of glutamatergic neurotransmission. Importantly, dysfunction of mGluRs and interacting proteins may lead to impaired signal transduction and finally result in neurological disorders, e.g., night blindness, addiction, epilepsy, schizophrenia, autism spectrum disorders and Parkinson's disease. In contrast to solved crystal structures of extracellular N-terminal domains of some mGluR types, only a few studies analyzed the conformation of intracellular receptor domains. Intracellular C-termini of most mGluR types are subject to alternative splicing and can be further modified by phosphorylation and SUMOylation. In this way, diverse interaction sites for intracellular proteins that bind to and regulate the glutamate receptors are generated. Indeed, most of the known mGluR binding partners interact with the receptors' C-terminal domains. Within the last years, different laboratories analyzed the structure of these domains and described the geometry of the contact surface between mGluR C-termini and interacting proteins. Here, I will review recent progress in the structure characterization of mGluR C-termini and provide an up-to-date summary of the geometry of these domains in contact with binding partners.
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Affiliation(s)
- Ralf Enz
- Emil-Fischer-Zentrum, Institut für Biochemie, Friedrich-Alexander-Universität Erlangen-Nürnberg Erlangen, Germany
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