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Li C, Moro S, Shostak K, O'Reilly FJ, Donzeau M, Graziadei A, McEwen AG, Desplancq D, Poussin-Courmontagne P, Bachelart T, Fiskin M, Berrodier N, Pichard S, Brillet K, Orfanoudakis G, Poterszman A, Torbeev V, Rappsilber J, Davey NE, Chariot A, Zanier K. Molecular mechanism of IKK catalytic dimer docking to NF-κB substrates. Nat Commun 2024; 15:7692. [PMID: 39227404 PMCID: PMC11371828 DOI: 10.1038/s41467-024-52076-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Accepted: 08/27/2024] [Indexed: 09/05/2024] Open
Abstract
The inhibitor of κB (IκB) kinase (IKK) is a central regulator of NF-κB signaling. All IKK complexes contain hetero- or homodimers of the catalytic IKKβ and/or IKKα subunits. Here, we identify a YDDΦxΦ motif, which is conserved in substrates of canonical (IκBα, IκBβ) and alternative (p100) NF-κB pathways, and which mediates docking to catalytic IKK dimers. We demonstrate a quantitative correlation between docking affinity and IKK activity related to IκBα phosphorylation/degradation. Furthermore, we show that phosphorylation of the motif's conserved tyrosine, an event previously reported to promote IκBα accumulation and inhibition of NF-κB gene expression, suppresses the docking interaction. Results from integrated structural analyzes indicate that the motif binds to a groove at the IKK dimer interface. Consistently, suppression of IKK dimerization also abolishes IκBα substrate binding. Finally, we show that an optimized bivalent motif peptide inhibits NF-κB signaling. This work unveils a function for IKKα/β dimerization in substrate motif recognition.
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Affiliation(s)
- Changqing Li
- Biotechnology and Cell Signaling (CNRS/Université de Strasbourg, UMR7242), Ecole Superieure de Biotechnologie de Strasbourg, Boulevard Sébastien Brant, 67400, Illkirch, France
| | - Stefano Moro
- Biotechnology and Cell Signaling (CNRS/Université de Strasbourg, UMR7242), Ecole Superieure de Biotechnologie de Strasbourg, Boulevard Sébastien Brant, 67400, Illkirch, France
| | - Kateryna Shostak
- Laboratory of Cancer Biology, GIGA Cancer, University of Liege, CHU, Sart-Tilman, 4000, Liege, Belgium
| | - Francis J O'Reilly
- Institute of Biotechnology, Technische Universität Berlin, Gustav-Meyer-Allee 25, Berlin, Germany
| | - Mariel Donzeau
- Biotechnology and Cell Signaling (CNRS/Université de Strasbourg, UMR7242), Ecole Superieure de Biotechnologie de Strasbourg, Boulevard Sébastien Brant, 67400, Illkirch, France
| | - Andrea Graziadei
- Institute of Biotechnology, Technische Universität Berlin, Gustav-Meyer-Allee 25, Berlin, Germany
| | - Alastair G McEwen
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC) / INSERM UMR-S 1258 / CNRS UMR7104/ Université de Strasbourg, 1 rue Laurent Fries, 67400, Illkirch, France
| | - Dominique Desplancq
- Biotechnology and Cell Signaling (CNRS/Université de Strasbourg, UMR7242), Ecole Superieure de Biotechnologie de Strasbourg, Boulevard Sébastien Brant, 67400, Illkirch, France
| | - Pierre Poussin-Courmontagne
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC) / INSERM UMR-S 1258 / CNRS UMR7104/ Université de Strasbourg, 1 rue Laurent Fries, 67400, Illkirch, France
| | - Thomas Bachelart
- Biotechnology and Cell Signaling (CNRS/Université de Strasbourg, UMR7242), Ecole Superieure de Biotechnologie de Strasbourg, Boulevard Sébastien Brant, 67400, Illkirch, France
| | - Mert Fiskin
- Biotechnology and Cell Signaling (CNRS/Université de Strasbourg, UMR7242), Ecole Superieure de Biotechnologie de Strasbourg, Boulevard Sébastien Brant, 67400, Illkirch, France
| | - Nicolas Berrodier
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC) / INSERM UMR-S 1258 / CNRS UMR7104/ Université de Strasbourg, 1 rue Laurent Fries, 67400, Illkirch, France
| | - Simon Pichard
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC) / INSERM UMR-S 1258 / CNRS UMR7104/ Université de Strasbourg, 1 rue Laurent Fries, 67400, Illkirch, France
| | - Karl Brillet
- Institut Biologie Moléculaire et Cellulaire (IBMC), CNRS UPR9002, 2 allée Konrad Roentgen, 67000, Strasbourg, France
| | - Georges Orfanoudakis
- Biotechnology and Cell Signaling (CNRS/Université de Strasbourg, UMR7242), Ecole Superieure de Biotechnologie de Strasbourg, Boulevard Sébastien Brant, 67400, Illkirch, France
| | - Arnaud Poterszman
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC) / INSERM UMR-S 1258 / CNRS UMR7104/ Université de Strasbourg, 1 rue Laurent Fries, 67400, Illkirch, France
| | - Vladimir Torbeev
- Biotechnology and Cell Signaling (CNRS/Université de Strasbourg, UMR7242), Ecole Superieure de Biotechnologie de Strasbourg, Boulevard Sébastien Brant, 67400, Illkirch, France
| | - Juri Rappsilber
- Institute of Biotechnology, Technische Universität Berlin, Gustav-Meyer-Allee 25, Berlin, Germany
| | - Norman E Davey
- Division of Cancer Biology, The Institute of Cancer Research, 237 Fulham Road, London, SW3 6JB, UK
| | - Alain Chariot
- Laboratory of Cancer Biology, GIGA Cancer, University of Liege, CHU, Sart-Tilman, 4000, Liege, Belgium
- WELBIO department, WEL Research Institute, avenue Pasteur, 6, 1300, Wavre, Belgium
| | - Katia Zanier
- Biotechnology and Cell Signaling (CNRS/Université de Strasbourg, UMR7242), Ecole Superieure de Biotechnologie de Strasbourg, Boulevard Sébastien Brant, 67400, Illkirch, France.
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Zhou N, Guo C, Du J, Xu Q, Li J, Huang D, Zheng X, Tu L. PPP1R14B-mediated phosphorylation enhances protein stability of RPS6KA1 to promote hepatocellular carcinoma tumorigenesis. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119840. [PMID: 39216602 DOI: 10.1016/j.bbamcr.2024.119840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2024] [Revised: 08/23/2024] [Accepted: 08/23/2024] [Indexed: 09/04/2024]
Abstract
Hepatocellular carcinoma (HCC) is one of the most prevalent cancers worldwide with a poor clinical prognosis. Protein phosphatase 1 regulatory subunit 14B (PPP1R14B) is an unidentified protein phosphatase 1 regulatory subunit that is associated with the occurrence and development of various cancers. Recently, PPP1R14B was found to contribute to paclitaxel resistance and cell progression in triple-negative breast cancer; however, the role of PPP1R14B in HCC is unknown. Here, we found that PPP1R14B was highly expressed in HCC tissues, which suggested a poor prognosis. Knockdown of PPP1R14B significantly inhibited the survival and tumorigenic ability of HCC cells, while overexpression of PPP1R14B had the opposite effects. Mechanistically, Ribosomal Protein S6 Kinase type 1(RPS6KA1) was identified as the target gene of PPP1R14B. PPP1R14B maintained the stability and phosphorylation of RPS6KA1, and positively regulated activation of the AKT/NF-κB pathway. Importantly, PPP1R14B-deficient tumor suppression could be partially restored by wild-type but not phosphorylated mutant RPS6KA1. Taken together, these findings shed light on the function and mechanism of PPP1R14B in HCC progression, indicating PPP1R14B is a promising molecular target for the treatment of HCC.
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Affiliation(s)
- Nana Zhou
- School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou 310053, China.
| | - Chaoqin Guo
- School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou 310053, China.
| | - Jingyang Du
- School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou 310053, China.
| | - Qiuran Xu
- Zhejiang Key Laboratory of Tumor Molecular Diagnosis and Individualized Medicine, Zhejiang Provincial People's Hospital, Affiliated People's Hospital, Hangzhou Medical College, Hangzhou 310014, China.
| | - Juejiashan Li
- School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou 310053, China.
| | - Dongsheng Huang
- Zhejiang Key Laboratory of Tumor Molecular Diagnosis and Individualized Medicine, Zhejiang Provincial People's Hospital, Affiliated People's Hospital, Hangzhou Medical College, Hangzhou 310014, China.
| | - Xiaoliang Zheng
- School of Laboratory Medicine and Bioengineering, Hangzhou Medical College, Hangzhou 310053, China; Key Discipline of Zhejiang Province in Public Health and Preventive Medicine (First Class, Category A), Hangzhou Medical College, Hangzhou 310053, China.
| | - Linglan Tu
- School of Laboratory Medicine and Bioengineering, Hangzhou Medical College, Hangzhou 310053, China.
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3
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Bartol TM, Ordyan M, Sejnowski TJ, Rangamani P, Kennedy MB. A spatial model of autophosphorylation of Ca 2+ /calmodulin-dependent protein kinase II in a glutamatergic spine reveals dynamics of kinase activation in the first several seconds after a complex synaptic stimulus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.02.578696. [PMID: 38352446 PMCID: PMC10862815 DOI: 10.1101/2024.02.02.578696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
Long-term potentiation (LTP) is a biochemical process in excitatory glutamatergic synapses in the Central Nervous System (CNS). It is initiated by a bout of synaptic activation that is strong enough to contribute to production of an action potential in the axon of the postsynaptic neuron, and it results in an increase in the size of postsynaptic depolarization during subsequent activity. The first step leading to LTP is activation and autophosphorylation of an abundant postsynaptic enzyme, Ca 2+ /calmodulin-dependent protein kinase II (CaMKII). We use simulation of activation of CaMKII holoenzymes in a realistic spatial model of a spine synapse, created in MCell4, to test three hypotheses about how the autophosphorylation response of CaMKII is shaped during a repeated high-frequency stimulus. First, the simulation results indicate that autophosphorylation of CaMKII does not constitute a bistable switch under biologically realistic conditions. Instead, prolonged autophosphorylation of CaMKII may contribute to a biochemical "kinetic proof-reading" mechanism that controls induction of synaptic plasticity. Second, concentration of CaMKII near the postsynaptic membrane increases the local concentration of kinase activity. However, neither localization nor "Ca 2+ -calmodulin-trapping (CaM-trapping)" increase the proportion of autophosphorylated subunits in holoenzymes after a complex stimulus, as previously hypothesized. Finally, we show that, as hypothesized, the amplitude of autophosphorylation in the first 30 seconds after a stimulus is extremely sensitive to the level and location of PP1 activity when PP1 is present in biologically accurate amounts. We further show that prolonged steric hindrance of dephosphorylation of CaMKII, caused by CaM-trapping, can increase the amplitude of autophosphorylation after a complex stimulus. These simulation results sharpen our quantitative understanding of the early events leading to LTP at excitatory synapses. Author Summary Neurons in the brain are interconnected in an organized fashion by synapses that transmit neuronal activity from one neuron to another. Most of the billions of neurons in the brain have about 10,000 synapses spread over the neuronal membrane. Information is stored in the brain when the ability of specific synapses to pass along neuronal activity is strengthened resulting in formation of new networks. The increase in strength of a synapse is tightly controlled by the frequency and amplitude of its activity, and by neurohormonal signals, which, in combination, can cause long-lasting biochemical changes at the synapse that underlie learning and memory. Defects in these biochemical pathways cause mental and neurological diseases. To develop treatments, we need to understand the precise choreography of these critical biochemical changes. However, the tiny size of the synaptic compartment makes precise measurements of the biochemical reactions impossible. We have used computer simulation techniques and information gathered from experiments on purified synaptic proteins to simulate, within a single synapse, the choreography of the first biochemical step in synaptic strengthening: activation of the enzyme Ca 2+ / calmodulin-dependent protein kinase II. Our results provide insights that can be used in future studies to develop treatments for neuronal diseases.
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Dias MH, Friskes A, Wang S, Fernandes Neto JM, van Gemert F, Mourragui S, Papagianni C, Kuiken HJ, Mainardi S, Alvarez-Villanueva D, Lieftink C, Morris B, Dekker A, van Dijk E, Wilms LH, da Silva MS, Jansen RA, Mulero-Sánchez A, Malzer E, Vidal A, Santos C, Salazar R, Wailemann RA, Torres TE, De Conti G, Raaijmakers JA, Snaebjornsson P, Yuan S, Qin W, Kovach JS, Armelin HA, te Riele H, van Oudenaarden A, Jin H, Beijersbergen RL, Villanueva A, Medema RH, Bernards R. Paradoxical Activation of Oncogenic Signaling as a Cancer Treatment Strategy. Cancer Discov 2024; 14:1276-1301. [PMID: 38533987 PMCID: PMC11215412 DOI: 10.1158/2159-8290.cd-23-0216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 12/06/2023] [Accepted: 03/19/2024] [Indexed: 03/28/2024]
Abstract
Cancer homeostasis depends on a balance between activated oncogenic pathways driving tumorigenesis and engagement of stress response programs that counteract the inherent toxicity of such aberrant signaling. Although inhibition of oncogenic signaling pathways has been explored extensively, there is increasing evidence that overactivation of the same pathways can also disrupt cancer homeostasis and cause lethality. We show here that inhibition of protein phosphatase 2A (PP2A) hyperactivates multiple oncogenic pathways and engages stress responses in colon cancer cells. Genetic and compound screens identify combined inhibition of PP2A and WEE1 as synergistic in multiple cancer models by collapsing DNA replication and triggering premature mitosis followed by cell death. This combination also suppressed the growth of patient-derived tumors in vivo. Remarkably, acquired resistance to this drug combination suppressed the ability of colon cancer cells to form tumors in vivo. Our data suggest that paradoxical activation of oncogenic signaling can result in tumor-suppressive resistance. Significance: A therapy consisting of deliberate hyperactivation of oncogenic signaling combined with perturbation of the stress responses that result from this is very effective in animal models of colon cancer. Resistance to this therapy is associated with loss of oncogenic signaling and reduced oncogenic capacity, indicative of tumor-suppressive drug resistance.
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Affiliation(s)
- Matheus Henrique Dias
- Division of Molecular Carcinogenesis, Oncode Institute, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
| | - Anoek Friskes
- Division of Cell Biology, Oncode Institute, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
| | - Siying Wang
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Joao M. Fernandes Neto
- Division of Molecular Carcinogenesis, Oncode Institute, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
| | - Frank van Gemert
- Division of Tumor Biology and Immunology, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
| | - Soufiane Mourragui
- Hubrecht Institute-KNAW (Royal Netherlands Academy of Arts and Sciences) and University Medical Center, Utrecht, the Netherlands.
| | - Chrysa Papagianni
- Division of Molecular Carcinogenesis, Oncode Institute, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
| | - Hendrik J. Kuiken
- Division of Molecular Carcinogenesis, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
| | - Sara Mainardi
- Division of Molecular Carcinogenesis, Oncode Institute, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
| | - Daniel Alvarez-Villanueva
- Chemoresistance and Predictive Factors Group, Program Against Cancer Therapeutic Resistance (ProCURE), Catalan Institute of Oncology (ICO), Oncobell Program, Bellvitge Biomedical Research Institute (IDIBELL), L’Hospitalet del Llobregat, Barcelona, Spain.
| | - Cor Lieftink
- Division of Molecular Carcinogenesis, NKI Robotic and Screening Center, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
| | - Ben Morris
- Division of Molecular Carcinogenesis, NKI Robotic and Screening Center, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
| | - Anna Dekker
- Division of Molecular Carcinogenesis, Oncode Institute, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
| | - Emma van Dijk
- Division of Molecular Carcinogenesis, Oncode Institute, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
| | - Lieke H.S. Wilms
- Division of Molecular Carcinogenesis, Oncode Institute, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
| | - Marcelo S. da Silva
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, SP, Brazil.
- Department of Chemical and Biological Sciences, Institute of Biosciences, São Paulo State University (UNESP), Botucatu, SP, Brazil.
| | - Robin A. Jansen
- Division of Molecular Carcinogenesis, Oncode Institute, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
| | - Antonio Mulero-Sánchez
- Division of Molecular Carcinogenesis, Oncode Institute, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
| | - Elke Malzer
- Division of Molecular Carcinogenesis, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
| | - August Vidal
- Department of Pathology, University Hospital of Bellvitge, Bellvitge Biomedical Research Institute (IDIBELL), L’Hospitalet de Llobregat, Barcelona, Spain.
- Xenopat S.L., Parc Cientific de Barcelona (PCB), Barcelona, Spain.
| | - Cristina Santos
- Department of Medical Oncology, Catalan Institute of Oncology (ICO), Oncobell Program, Bellvitge Biomedical Research Institute (IDIBELL), CIBERONC, Barcelona, Spain.
| | - Ramón Salazar
- Department of Medical Oncology, Catalan Institute of Oncology (ICO), Oncobell Program, Bellvitge Biomedical Research Institute (IDIBELL), CIBERONC, Barcelona, Spain.
| | | | - Thompson E.P. Torres
- Center of Toxins, Immune-response and Cell Signaling, Instituto Butantan, São Paulo, Brazil.
- Department of Clinical and Experimental Oncology, Federal University of São Paulo (UNIFESP), São Paulo, Brazil.
| | - Giulia De Conti
- Division of Molecular Carcinogenesis, Oncode Institute, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
| | - Jonne A. Raaijmakers
- Division of Cell Biology, Oncode Institute, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
| | - Petur Snaebjornsson
- Department of Pathology, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
- University of Iceland, Faculty of Medicine, Reykjavik, Iceland.
| | - Shengxian Yuan
- The Third Department of Hepatic Surgery, Eastern Hepatobiliary Surgery Hospital, Shanghai, China.
| | - Wenxin Qin
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - John S. Kovach
- Lixte Biotechnology Holdings, Inc., Pasadena, California.
| | - Hugo A. Armelin
- Center of Toxins, Immune-response and Cell Signaling, Instituto Butantan, São Paulo, Brazil.
| | - Hein te Riele
- Division of Tumor Biology and Immunology, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
| | - Alexander van Oudenaarden
- Hubrecht Institute-KNAW (Royal Netherlands Academy of Arts and Sciences) and University Medical Center, Utrecht, the Netherlands.
| | - Haojie Jin
- Division of Molecular Carcinogenesis, Oncode Institute, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Roderick L. Beijersbergen
- Division of Molecular Carcinogenesis, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
- Division of Molecular Carcinogenesis, NKI Robotic and Screening Center, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
| | - Alberto Villanueva
- Chemoresistance and Predictive Factors Group, Program Against Cancer Therapeutic Resistance (ProCURE), Catalan Institute of Oncology (ICO), Oncobell Program, Bellvitge Biomedical Research Institute (IDIBELL), L’Hospitalet del Llobregat, Barcelona, Spain.
- Xenopat S.L., Parc Cientific de Barcelona (PCB), Barcelona, Spain.
| | - Rene H. Medema
- Division of Cell Biology, Oncode Institute, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
| | - Rene Bernards
- Division of Molecular Carcinogenesis, Oncode Institute, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
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Foley K, McKee C, Mayer A, Ganguly A, Barnett D, Ward N, Zhang Y, Nairn A, Xia H. PP1β opposes classic PP1 function, inhibiting spine maturation and promoting LTP. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.01.26.525737. [PMID: 36747779 PMCID: PMC9901188 DOI: 10.1101/2023.01.26.525737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Protein phosphatase 1 (PP1) regulates synaptic plasticity and has been described as a molecular constraint on learning and memory. There are three neuronal isoforms, PP1α, PP1β, and PP1γ, but little is known about their individual functions. PP1α and PP1γ are assumed to mediate the effects of PP1 on learning and memory based on their enrichment at dendritic spines and their preferential binding to neurabin and spinophilin, major PP1 synaptic scaffolding proteins. However, it was recently discovered that human de novo PP1β mutations cause intellectual disability, suggesting an important but ill-defined role for PP1β. In this study, we investigated the functions of each PP1 isoform in hippocampal synaptic physiology using conditional CA1-specific knockout mice. In stark contrast to classic PP1 function, we found that PP1β promotes synaptic plasticity as well as spatial memory. These changes in synaptic plasticity and memory are accompanied by changes in GluA1 phosphorylation, GluN2A levels, and dendritic spine density and morphology, including silent synapse number. These functions of PP1β reveal a previously unidentified signaling pathway regulating spine maturation and plasticity, broadening our understanding of the complex role of PP1 in synaptic physiology.
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Bonsor DA, Simanshu DK. RAS and SHOC2 Roles in RAF Activation and Therapeutic Considerations. ANNUAL REVIEW OF CANCER BIOLOGY 2024; 8:97-113. [PMID: 38882927 PMCID: PMC11178279 DOI: 10.1146/annurev-cancerbio-062822-030450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2024]
Abstract
Mutations in RAS proteins play a pivotal role in the development of human cancers, driving persistent RAF activation and deregulating the Mitogen-Activated Protein Kinase (MAPK) signaling pathway. While progress has been made in targeting specific oncogenic RAS proteins, effective drug-based therapies for the majority of RAS mutations remain limited. Recent investigations on RAS-RAF complexes and the SHOC2-MRAS-PP1C holoenzyme complex have provided crucial insights into the structural and functional aspects of RAF activation within the MAPK signaling pathway. Moreover, these studies have also unveiled new blueprints for developing inhibitors allowing us to think beyond the current RAS and MEK inhibitors. In this review, we explore the roles of RAS and SHOC2 in activating RAF and discuss potential therapeutic strategies to target these proteins. A comprehensive understanding of the molecular interactions involved in RAF activation and their therapeutic implications holds the potential to drive innovative approaches in combating RAS/RAF-driven cancers.
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Affiliation(s)
- Daniel A. Bonsor
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Dhirendra K. Simanshu
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
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7
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Wu X, Zhang L, Liu C, Cheng Q, Zhao W, Chen P, Qin Y, Chen M. The NS2B-PP1α-eIF2α axis: Inhibiting stress granule formation and Boosting Zika virus replication. PLoS Pathog 2024; 20:e1012355. [PMID: 38935808 PMCID: PMC11236161 DOI: 10.1371/journal.ppat.1012355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 07/10/2024] [Accepted: 06/19/2024] [Indexed: 06/29/2024] Open
Abstract
Stress granules (SGs), formed by untranslated messenger ribonucleoproteins (mRNPs) during cellular stress in eukaryotes, have been linked to flavivirus interference without clear understanding. This study reveals the role of Zika virus (ZIKV) NS2B as a scaffold protein mediating interaction between protein phosphatase 1α (PP1α) and eukaryotic initiation factor 2α (eIF2α). This interaction promotes eIF2α dephosphorylation by PP1α, inhibiting SG formation. The NS2B-PP1α complex exhibits remarkable stability, resisting ubiquitin-induced degradation and amplifying eIF2α dephosphorylation, thus promoting ZIKV replication. In contrast, the NS2BV35A mutant, interacting exclusively with eIF2α, fails to inhibit SG formation, resulting in reduced viral replication and diminished impact on brain organoid growth. These findings reveal PP1α's dual role in ZIKV infection, inducing interferon production as an antiviral factor and suppressing SG formation as a viral promoter. Moreover, we found that NS2B also serves as a versatile mechanism employed by flaviviruses to counter host antiviral defenses, primarily by broadly inhibiting SG formation. This research advances our comprehension of the complex interplay in flavivirus-host interactions, offering potential for innovative therapeutic strategies against flavivirus infections.
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Affiliation(s)
- Xiaoyan Wu
- State Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, China
| | - Linliang Zhang
- College of Life Sciences, Hubei University, Wuhan, China
| | - Cong Liu
- State Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, China
| | - Qi Cheng
- Wuhan Jinyintan Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Wen Zhao
- Tissue Engineering and Organ Manufacturing (TEOM) lab, Department of Biomedical Engineering, Wuhan University Taikang Medical School (School of Basic Medical Sciences), Wuhan, China
| | - Pu Chen
- Tissue Engineering and Organ Manufacturing (TEOM) lab, Department of Biomedical Engineering, Wuhan University Taikang Medical School (School of Basic Medical Sciences), Wuhan, China
- Taikang Center for Life and Medical Sciences, Wuhan University, Wuhan, China
| | - Yali Qin
- State Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, China
- College of Life Sciences, Hubei University, Wuhan, China
| | - Mingzhou Chen
- State Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, China
- College of Life Sciences, Hubei University, Wuhan, China
- Taikang Center for Life and Medical Sciences, Wuhan University, Wuhan, China
- Hubei Jiangxia Laboratory, Wuhan, China
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8
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Lu HJ, Koju N, Sheng R. Mammalian integrated stress responses in stressed organelles and their functions. Acta Pharmacol Sin 2024; 45:1095-1114. [PMID: 38267546 PMCID: PMC11130345 DOI: 10.1038/s41401-023-01225-0] [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: 06/29/2023] [Accepted: 12/30/2023] [Indexed: 01/26/2024] Open
Abstract
The integrated stress response (ISR) triggered in response to various cellular stress enables mammalian cells to effectively cope with diverse stressful conditions while maintaining their normal functions. Four kinases (PERK, PKR, GCN2, and HRI) of ISR regulate ISR signaling and intracellular protein translation via mediating the phosphorylation of eukaryotic translation initiation factor 2 α (eIF2α) at Ser51. Early ISR creates an opportunity for cells to repair themselves and restore homeostasis. This effect, however, is reversed in the late stages of ISR. Currently, some studies have shown the non-negligible impact of ISR on diseases such as ischemic diseases, cognitive impairment, metabolic syndrome, cancer, vanishing white matter, etc. Hence, artificial regulation of ISR and its signaling with ISR modulators becomes a promising therapeutic strategy for relieving disease symptoms and improving clinical outcomes. Here, we provide an overview of the essential mechanisms of ISR and describe the ISR-related pathways in organelles including mitochondria, endoplasmic reticulum, Golgi apparatus, and lysosomes. Meanwhile, the regulatory effects of ISR modulators and their potential application in various diseases are also enumerated.
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Affiliation(s)
- Hao-Jun Lu
- Department of Pharmacology and Laboratory of Aging and Nervous Diseases, Jiangsu Key Laboratory of Neuropsychiatric Diseases, College of Pharmaceutical Sciences of Soochow University, Suzhou, 215123, China
| | - Nirmala Koju
- Department of Pharmacology and Laboratory of Aging and Nervous Diseases, Jiangsu Key Laboratory of Neuropsychiatric Diseases, College of Pharmaceutical Sciences of Soochow University, Suzhou, 215123, China
| | - Rui Sheng
- Department of Pharmacology and Laboratory of Aging and Nervous Diseases, Jiangsu Key Laboratory of Neuropsychiatric Diseases, College of Pharmaceutical Sciences of Soochow University, Suzhou, 215123, China.
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9
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Gao S, Carrasquillo Rodríguez JW, Bahmanyar S, Airola MV. Structure and mechanism of the human CTDNEP1-NEP1R1 membrane protein phosphatase complex necessary to maintain ER membrane morphology. Proc Natl Acad Sci U S A 2024; 121:e2321167121. [PMID: 38776370 PMCID: PMC11145253 DOI: 10.1073/pnas.2321167121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 04/12/2024] [Indexed: 05/25/2024] Open
Abstract
C-terminal Domain Nuclear Envelope Phosphatase 1 (CTDNEP1) is a noncanonical protein serine/threonine phosphatase that has a conserved role in regulating ER membrane biogenesis. Inactivating mutations in CTDNEP1 correlate with the development of medulloblastoma, an aggressive childhood cancer. The transmembrane protein Nuclear Envelope Phosphatase 1 Regulatory Subunit 1 (NEP1R1) binds CTDNEP1, but the molecular details by which NEP1R1 regulates CTDNEP1 function are unclear. Here, we find that knockdown of NEP1R1 generates identical phenotypes to reported loss of CTDNEP1 in mammalian cells, establishing CTDNEP1-NEP1R1 as an evolutionarily conserved membrane protein phosphatase complex that restricts ER expansion. Mechanistically, NEP1R1 acts as an activating regulatory subunit that directly binds and increases the phosphatase activity of CTDNEP1. By defining a minimal NEP1R1 domain sufficient to activate CTDNEP1, we determine high-resolution crystal structures of the CTDNEP1-NEP1R1 complex bound to a peptide sequence acting as a pseudosubstrate. Structurally, NEP1R1 engages CTDNEP1 at a site distant from the active site to stabilize and allosterically activate CTDNEP1. Substrate recognition is facilitated by a conserved Arg residue in CTDNEP1 that binds and orients the substrate peptide in the active site. Together, this reveals mechanisms for how NEP1R1 regulates CTDNEP1 and explains how cancer-associated mutations inactivate CTDNEP1.
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Affiliation(s)
- Shujuan Gao
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY11794
| | | | - Shirin Bahmanyar
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT06511
| | - Michael V. Airola
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY11794
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10
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Mestareehi A, Abu-Farsakh N. Impact of Protein Phosphatase Expressions on the Prognosis of Hepatocellular Carcinoma Patients. ACS OMEGA 2024; 9:10299-10331. [PMID: 38463290 PMCID: PMC10918787 DOI: 10.1021/acsomega.3c07787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 02/02/2024] [Accepted: 02/08/2024] [Indexed: 03/12/2024]
Abstract
The study was conducted to unveil the significance of protein phosphatases in the prognosis of hepatocellular carcinoma (HCC) patients and its related molecular biological attributes as well as to discover novel potential biomarkers for therapeutic significance and diagnostic purposes that may benefit clinical practice. Analyzing a data set from 159 HCC patients using high-throughput phosphoproteomics, we examined the dysregulated expression of protein phosphatases. Employing bioinformatic and pathway analyses, we explored differentially expressed genes linked to protein phosphatases. A protein-protein interaction network was constructed using the search tool for the retrieval of interacting genes/proteins database. We quantified a total of 11,547 phosphorylation sites associated with 4043 phosphoproteins from HCC patients. Within this data set, we identified 105 identified phosphorylation sites associated with protein phosphatases; 28 genes were upregulated and 3 were downregulated in HCC. Enriched pathways using Gene Set Enrichment Analysis encompassed oocyte meiosis, proteoglycans in cancer, the oxytocin signaling pathway, the cGMP-PKG signaling pathway, the vascular smooth muscle, and the cAMP signaling pathway. The Kyoto encyclopedia of genes and genomes (KEGG) analysis highlighted pathways like mitogen-activated protein kinase, AMPK, and PI3K-Akt, indicating potential involvement in HCC progression. Notably, the PPI network identified hub genes, emphasizing their interconnections and potential roles in HCC. In our study, we found significantly upregulated levels of CDC25C, PPP1R13L, and PPP1CA, which emerge as promising avenues. This significant expression could serve as potent diagnostic and prognostic markers to enhance the effectiveness of HCC cancer treatment, offering efficiency and accuracy in patient assessment. The findings regarding protein phosphatases reveal their elevated expression in HCC, correlating with unfavorable prognosis. Moreover, the outcomes of gene ontology and KEGG pathway analyses suggest that protein phosphatases may influence liver cancer by engaging diverse targets and pathways, ultimately fostering the progression of HCC. These results underscore the substantial potential of protein phosphatases as key contributors to HCC's development and advancement. This insight holds promise for identifying therapeutic targets and charting research avenues to enhance the comprehension of the intricate molecular mechanisms underpinning HCC.
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Affiliation(s)
- Aktham Mestareehi
- Department
of Pharmaceutical Sciences, Faculty of Pharmacy, Isra University, P.O. Box 22, Amman 11622, Jordan
- Department
of Pharmaceutical Sciences, School of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan 48201, United States
- School
of Medicine, The Ohio State University, Columbus, Ohio 43202, United States
| | - Noor Abu-Farsakh
- Department
of Gastroenterology and Hepatology, Internal Medicine Department, Jordan University Hospital, Amman 11942, Jordan
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11
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Osawa J, Karakawa M, Taniguchi A, Inui Y, Usuki C, Ishida A, Kameshita I, Sueyoshi N. Functional regulation of the protein phosphatase PPM1M by phosphorylation at multiple sites with Ser/Thr-Pro motifs. Arch Biochem Biophys 2024; 753:109887. [PMID: 38224862 DOI: 10.1016/j.abb.2024.109887] [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: 11/03/2023] [Revised: 12/22/2023] [Accepted: 01/09/2024] [Indexed: 01/17/2024]
Abstract
The imbalance in the phosphorylation and the dephosphorylation of proteins leads to various diseases. Therefore, in vivo, the functions of protein kinases and protein phosphatases are strictly regulated. Mg2+/Mn2+-dependent protein phosphatase PPM1M has been implicated in immunity and cancer; however, the regulation mechanism remains unknown. In this study, we show that PPM1M is regulated in different ways by multiple phosphorylation. PPM1M has four Ser/Thr-Pro motifs (Ser27, Ser43, Ser60, and Thr254) that are recognized by proline-directed kinases, and Ser60 was found to be phosphorylated by cyclin-dependent kinase 5 (CDK5) in the cell. The phospho-mimetic mutation of Ser27 and Ser43 in the N-terminal domain suppresses the nuclear localization of PPM1M and promotes its accumulation in the cytoplasm. The phospho-mimetic mutation of Ser60 decreases PPM1M activity; conversely, the phospho-mimetic mutation of Thr254 increases PPM1M activity. These results suggest that the subcellular localization and phosphatase activity of PPM1M are regulated by protein kinases, including CDK5, via phosphorylation at multiple sites. Thus, PPM1M is differentially regulated by proline-directed kinases, including CDK5.
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Affiliation(s)
- Jin Osawa
- Department of Life Sciences, Faculty of Agriculture, Kagawa University, Kagawa, 761-0795, Japan
| | - Masataka Karakawa
- Department of Life Sciences, Faculty of Agriculture, Kagawa University, Kagawa, 761-0795, Japan
| | - Aoi Taniguchi
- Department of Life Sciences, Faculty of Agriculture, Kagawa University, Kagawa, 761-0795, Japan
| | - Yuiko Inui
- Department of Life Sciences, Faculty of Agriculture, Kagawa University, Kagawa, 761-0795, Japan
| | - Chika Usuki
- Department of Life Sciences, Faculty of Agriculture, Kagawa University, Kagawa, 761-0795, Japan
| | - Atsuhiko Ishida
- Laboratory of Molecular Brain Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-8521, Japan.
| | - Isamu Kameshita
- Department of Life Sciences, Faculty of Agriculture, Kagawa University, Kagawa, 761-0795, Japan
| | - Noriyuki Sueyoshi
- Department of Life Sciences, Faculty of Agriculture, Kagawa University, Kagawa, 761-0795, Japan.
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12
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Liu C, Chen L, Cong Y, Cheng L, Shuai Y, Lv F, Chen K, Song Y, Xing Y. Protein phosphatase 1 regulatory subunit 15 A promotes translation initiation and induces G2M phase arrest during cuproptosis in cancers. Cell Death Dis 2024; 15:149. [PMID: 38365764 PMCID: PMC10873343 DOI: 10.1038/s41419-024-06489-w] [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: 11/04/2023] [Revised: 01/19/2024] [Accepted: 01/22/2024] [Indexed: 02/18/2024]
Abstract
Copper ions play a crucial role as cofactors for essential enzymes in cellular processes. However, when the intracellular concentration of copper ions exceeds the homeostatic threshold, they become toxic to cells. In our study, we demonstrated that elesclomol, as a carrier of copper ions, caused an upregulation of protein phosphatase 1 regulatory subunit 15 A (PPP1R15A), which plays a role in regulating substrate selectivity of protein phosphatase 1 during cuproptosis. Mechanistically, we investigated that PPP1R15A activated translation initiation by dephosphorylating eukaryotic translation initiation factor 2 subunit alpha at the S51 residue through protein phosphatase 1 and phosphorylating eukaryotic translation initiation factor 4E binding protein 1 at the T70 residue. In addition, PPP1R15A reduced H3K4 methylation by altering the phosphorylation of histone methyltransferases, which led to the silencing of MYC and G2M phase arrest.
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Affiliation(s)
- Chunyu Liu
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430022, Wuhan, China
| | - Liang Chen
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430022, Wuhan, China
| | - Yukun Cong
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430022, Wuhan, China
| | - Lulin Cheng
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430022, Wuhan, China
| | - Yujun Shuai
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430022, Wuhan, China
| | - Fang Lv
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430022, Wuhan, China
| | - Kang Chen
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430022, Wuhan, China
| | - Yarong Song
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430022, Wuhan, China.
| | - Yifei Xing
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430022, Wuhan, China.
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13
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Egbert JR, Silbern I, Uliasz TF, Lowther KM, Yee SP, Urlaub H, Jaffe LA. Phosphatases modified by LH signaling in ovarian follicles: testing their role in regulating the NPR2 guanylyl cyclase†. Biol Reprod 2024; 110:102-115. [PMID: 37774352 PMCID: PMC10790345 DOI: 10.1093/biolre/ioad130] [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] [Indexed: 10/01/2023] Open
Abstract
In response to luteinizing hormone (LH), multiple proteins in rat and mouse granulosa cells are rapidly dephosphorylated, but the responsible phosphatases remain to be identified. Because the phosphorylation state of phosphatases can regulate their interaction with substrates, we searched for phosphatases that might function in LH signaling by using quantitative mass spectrometry. We identified all proteins in rat ovarian follicles whose phosphorylation state changed detectably in response to a 30-min exposure to LH, and within this list, identified protein phosphatases or phosphatase regulatory subunits that showed changes in phosphorylation. Phosphatases in the phosphoprotein phosphatase (PPP) family were of particular interest because of their requirement for dephosphorylating the natriuretic peptide receptor 2 (NPR2) guanylyl cyclase in the granulosa cells, which triggers oocyte meiotic resumption. Among the PPP family regulatory subunits, PPP1R12A and PPP2R5D showed the largest increases in phosphorylation, with 4-10 fold increases in signal intensity on several sites. Although follicles from mice in which these phosphorylations were prevented by serine-to-alanine mutations in either Ppp1r12a or Ppp2r5d showed normal LH-induced NPR2 dephosphorylation, these regulatory subunits and others could act redundantly to dephosphorylate NPR2. Our identification of phosphatases and other proteins whose phosphorylation state is rapidly modified by LH provides clues about multiple signaling pathways in ovarian follicles.
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Affiliation(s)
- Jeremy R Egbert
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT, USA
| | - Ivan Silbern
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Multidisciplinary Sciences, Goettingen, Germany
- Institute of Clinical Chemistry, University Medical Center Goettingen, Goettingen, Germany
| | - Tracy F Uliasz
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT, USA
| | - Katie M Lowther
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT, USA
- Center for Mouse Genome Modification, University of Connecticut Health Center, Farmington CT, USA
| | - Siu-Pok Yee
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT, USA
- Center for Mouse Genome Modification, University of Connecticut Health Center, Farmington CT, USA
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Multidisciplinary Sciences, Goettingen, Germany
- Institute of Clinical Chemistry, University Medical Center Goettingen, Goettingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells” (MBExC), University of Göttingen, Göttingen, Germany
| | - Laurinda A Jaffe
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT, USA
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14
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Kommer DC, Stamatiou K, Vagnarelli P. Cell Cycle-Specific Protein Phosphatase 1 (PP1) Substrates Identification Using Genetically Modified Cell Lines. Methods Mol Biol 2024; 2740:37-61. [PMID: 38393468 DOI: 10.1007/978-1-0716-3557-5_3] [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] [Indexed: 02/25/2024]
Abstract
The identification of protein phosphatase 1 (PP1) holoenzyme substrates has proven to be a challenging task. PP1 can form different holoenzyme complexes with a variety of regulatory subunits, and many of those are cell cycle regulated. Although several methods have been used to identify PP1 substrates, their cell cycle specificity is still an unmet need. Here, we present a new strategy to investigate PP1 substrates throughout the cell cycle using clustered regularly interspersed short palindromic repeats (CRISPR)-Cas9 genome editing and generate cell lines with endogenously tagged PP1 regulatory subunit (regulatory interactor of protein phosphatase one, RIPPO). RIPPOs are tagged with the auxin-inducible degron (AID) or ascorbate peroxidase 2 (APEX2) modules, and PP1 substrate identification is conducted by SILAC proteomic-based approaches. Proteins in close proximity to RIPPOs are first identified through mass spectrometry (MS) analyses using the APEX2 system; then a list of differentially phosphorylated proteins upon RIPPOs rapid degradation (achieved via the AID system) is compiled via SILAC phospho-mass spectrometry. The "in silico" overlap between the two proteomes will be enriched for PP1 putative substrates. Several methods including fluorescence resonance energy transfer (FRET), proximity ligation assays (PLA), and in vitro assays can be used as substrate validations approaches.
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Affiliation(s)
- Dorothee C Kommer
- College of Health, Medicine and Life Science, Brunel University London, London, UK
| | | | - Paola Vagnarelli
- College of Health, Medicine and Life Science, Brunel University London, London, UK.
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15
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Choy MS, Srivastava G, Robinson LC, Tatchell K, Page R, Peti W. The SDS22:PP1:I3 complex: SDS22 binding to PP1 loosens the active site metal to prime metal exchange. J Biol Chem 2024; 300:105515. [PMID: 38042495 PMCID: PMC10776994 DOI: 10.1016/j.jbc.2023.105515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 11/20/2023] [Accepted: 11/22/2023] [Indexed: 12/04/2023] Open
Abstract
SDS22 and Inhibitor-3 (I3) are two ancient regulators of protein phosphatase 1 (PP1) that regulate multiple essential biological processes. Both SDS22 and I3 form stable dimeric complexes with PP1; however, and atypically for PP1 regulators, they also form a triple complex, where both proteins bind to PP1 simultaneously (SPI complex). Here we report the crystal structure of the SPI complex. While both regulators bind PP1 in conformations identical to those observed in their individual PP1 complexes, PP1 adopts the SDS22-bound conformation, which lacks its M1 metal. Unexpectedly, surface plasmon resonance (SPR) revealed that the affinity of I3 for the SDS22:PP1 complex is ∼10-fold lower than PP1 alone. We show that this change in binding affinity is solely due to the interaction of I3 with the PP1 active site, specifically PP1's M2 metal, demonstrating that SDS22 likely allows for PP1 M2 metal exchange and thus PP1 biogenesis.
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Affiliation(s)
- Meng S Choy
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Gautam Srivastava
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Lucy C Robinson
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA
| | - Kelly Tatchell
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA
| | - Rebecca Page
- Department of Cell Biology, University of Connecticut Health Center, Farmington, Connecticut, USA.
| | - Wolfgang Peti
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, Connecticut, USA.
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16
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Claes Z, Bollen M. A split-luciferase lysate-based approach to identify small-molecule modulators of phosphatase subunit interactions. Cell Chem Biol 2023; 30:1666-1679.e6. [PMID: 37625414 DOI: 10.1016/j.chembiol.2023.07.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 05/31/2023] [Accepted: 07/30/2023] [Indexed: 08/27/2023]
Abstract
An emerging strategy for the therapeutic targeting of protein phosphatases involves the use of compounds that interfere with the binding of regulatory subunits or substrates. However, high-throughput screening strategies for such interfering molecules are scarce. Here, we report on the conversion of the NanoBiT split-luciferase system into a robust assay for the quantification of phosphatase subunit and substrate interactions in cell lysates. The assay is suitable to screen small-molecule libraries for interfering compounds. We designed and validated split-luciferase sensors for a broad range of PP1 and PP2A holoenzymes, including sensors that selectively report on weak interaction sites. To facilitate efficient hit triaging in large-scale screening campaigns, deselection procedures were developed to eliminate assay-interfering molecules with high fidelity. As a proof-of-principle, we successfully applied the split-luciferase screening tool to identify small-molecule disruptors of the interaction between the C-terminus of PP1β and the ankyrin-repeat domain of the myosin-phosphatase targeting subunit MYPT1.
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Affiliation(s)
- Zander Claes
- Laboratory of Biosignaling and Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, 3000 Leuven, Belgium
| | - Mathieu Bollen
- Laboratory of Biosignaling and Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, 3000 Leuven, Belgium.
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17
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Iannotta L, Emanuele M, Favetta G, Tombesi G, Vandewynckel L, Lara Ordóñez AJ, Saliou JM, Drouyer M, Sibran W, Civiero L, Nichols RJ, Athanasopoulos PS, Kortholt A, Chartier-Harlin MC, Greggio E, Taymans JM. PAK6-mediated phosphorylation of PPP2R2C regulates LRRK2-PP2A complex formation. Front Mol Neurosci 2023; 16:1269387. [PMID: 38169846 PMCID: PMC10759229 DOI: 10.3389/fnmol.2023.1269387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Accepted: 11/20/2023] [Indexed: 01/05/2024] Open
Abstract
Mutations in leucine-rich repeat kinase 2 (LRRK2) are a common cause of inherited and sporadic Parkinson's disease (PD) and previous work suggests that dephosphorylation of LRRK2 at a cluster of heterologous phosphosites is associated to disease. We have previously reported subunits of the PP1 and PP2A classes of phosphatases as well as the PAK6 kinase as regulators of LRRK2 dephosphorylation. We therefore hypothesized that PAK6 may have a functional link with LRRK2's phosphatases. To investigate this, we used PhosTag gel electrophoresis with purified proteins and found that PAK6 phosphorylates the PP2A regulatory subunit PPP2R2C at position S381. While S381 phosphorylation did not affect PP2A holoenzyme formation, a S381A phosphodead PPP2R2C showed impaired binding to LRRK2. Also, PAK6 kinase activity changed PPP2R2C subcellular localization in a S381 phosphorylation-dependent manner. Finally, PAK6-mediated dephosphorylation of LRRK2 was unaffected by phosphorylation of PPP2R2C at S381, suggesting that the previously reported mechanism whereby PAK6-mediated phosphorylation of 14-3-3 proteins promotes 14-3-3-LRRK2 complex dissociation and consequent exposure of LRRK2 phosphosites for dephosphorylation is dominant. Taken together, we conclude that PAK6-mediated phosphorylation of PPP2R2C influences the recruitment of PPP2R2C to the LRRK2 complex and PPP2R2C subcellular localization, pointing to an additional mechanism in the fine-tuning of LRRK2 phosphorylation.
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Affiliation(s)
- Lucia Iannotta
- Department of Biology, University of Padova, Padua, Italy
- National Research Council, c/o Humanitas Research Hospital, Institute of Neuroscience, Rozzano, Italy
| | - Marco Emanuele
- Univ. Lille, Inserm, CHU Lille, UMR-S 1172 - LilNCog - Lille Neuroscience & Cognition, Lille, France
| | - Giulia Favetta
- Department of Biology, University of Padova, Padua, Italy
| | - Giulia Tombesi
- Department of Biology, University of Padova, Padua, Italy
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Laurine Vandewynckel
- Univ. Lille, Inserm, CHU Lille, UMR-S 1172 - LilNCog - Lille Neuroscience & Cognition, Lille, France
| | | | - Jean-Michel Saliou
- University of Lille, CNRS, Inserm, CHU Lille, Institute Pasteur de Lille, US 41 – UAR 2014 – PLBS, Lille, France
| | - Matthieu Drouyer
- Univ. Lille, Inserm, CHU Lille, UMR-S 1172 - LilNCog - Lille Neuroscience & Cognition, Lille, France
| | - William Sibran
- Univ. Lille, Inserm, CHU Lille, UMR-S 1172 - LilNCog - Lille Neuroscience & Cognition, Lille, France
| | - Laura Civiero
- Department of Biology, University of Padova, Padua, Italy
- IRCSS, San Camillo Hospital, Venice, Italy
| | - R. Jeremy Nichols
- Department of Pathology, Stanford University, Stanford, CA, United States
| | | | - Arjan Kortholt
- Department of Cell Biochemistry, University of Groningen, Groningen, Netherlands
- YETEM-Innovative Technologies Application and Research Centre, Suleyman Demirel University West Campus, Isparta, Turkey
| | | | - Elisa Greggio
- Department of Biology, University of Padova, Padua, Italy
- Centro Studi per la Neurodegenerazione (CESNE), University of Padova, Padua, Italy
| | - Jean-Marc Taymans
- Univ. Lille, Inserm, CHU Lille, UMR-S 1172 - LilNCog - Lille Neuroscience & Cognition, Lille, France
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18
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Fonódi M, Thalwieser Z, Csortos C, Boratkó A. TIMAP, a Regulatory Subunit of Protein Phosphatase 1, Inhibits In Vitro Neuronal Differentiation. Int J Mol Sci 2023; 24:17360. [PMID: 38139189 PMCID: PMC10744335 DOI: 10.3390/ijms242417360] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2023] [Revised: 12/06/2023] [Accepted: 12/07/2023] [Indexed: 12/24/2023] Open
Abstract
TIMAP (TGF-β-inhibited membrane associated protein) is abundant in endothelial cells, and it has been regarded as a member of the myosin phosphatase targeting protein (MYPT) family. Our workgroup previously identified several interacting protein partners of TIMAP and proved its regulatory subunit role for protein phosphatase 1 catalytic subunit (PP1c). TIMAP is also expressed in neuronal cells, but details of its function have not been studied yet. Therefore, we aimed to explore the role of TIMAP in neuronal cells, especially during differentiation. Expression of TIMAP was proved both at mRNA and protein levels in SH-SY5Y human neuroblastoma cells. Differentiation of SH-SY5Y cells was optimized and proved by the detection of neuronal differentiation markers, such as β3-tubulin, nestin and inhibitor of differentiation 1 (ID1) using qPCR and Western blot. We found downregulation of TIMAP during differentiation. In accordance with this, overexpression of recombinant TIMAP attenuated the differentiation of neuronal cells. Moreover, the subcellular localization of TIMAP has changed during differentiation as it translocated from the plasma membrane into the nucleus. The nuclear interactome of TIMAP revealed more than 50 proteins, offering the possibility to further investigate the role of TIMAP in several key physiological pathways of neuronal cells.
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Affiliation(s)
| | | | | | - Anita Boratkó
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Egyetem Tér 1, H-4032 Debrecen, Hungary; (M.F.); (Z.T.); (C.C.)
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19
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Hicks D, Giresh K, Wrischnik LA, Weiser DC. The PPP1R15 Family of eIF2-alpha Phosphatase Targeting Subunits (GADD34 and CReP). Int J Mol Sci 2023; 24:17321. [PMID: 38139150 PMCID: PMC10743859 DOI: 10.3390/ijms242417321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Revised: 12/01/2023] [Accepted: 12/08/2023] [Indexed: 12/24/2023] Open
Abstract
The vertebrate PPP1R15 family consists of the proteins GADD34 (growth arrest and DNA damage-inducible protein 34, the product of the PPP1R15A gene) and CReP (constitutive repressor of eIF2α phosphorylation, the product of the PPP1R15B gene), both of which function as targeting/regulatory subunits for protein phosphatase 1 (PP1) by regulating subcellular localization, modulating substrate specificity and assembling complexes with target proteins. The primary cellular function of these proteins is to facilitate the dephosphorylation of eukaryotic initiation factor 2-alpha (eIF2α) by PP1 during cell stress. In this review, we will provide a comprehensive overview of the cellular function, biochemistry and pharmacology of GADD34 and CReP, starting with a brief introduction of eIF2α phosphorylation via the integrated protein response (ISR). We discuss the roles GADD34 and CReP play as feedback inhibitors of the unfolded protein response (UPR) and highlight the critical function they serve as inhibitors of the PERK-dependent branch, which is particularly important since it can mediate cell survival or cell death, depending on how long the stressful stimuli lasts, and GADD34 and CReP play key roles in fine-tuning this cellular decision. We briefly discuss the roles of GADD34 and CReP homologs in model systems and then focus on what we have learned about their function from knockout mice and human patients, followed by a brief review of several diseases in which GADD34 and CReP have been implicated, including cancer, diabetes and especially neurodegenerative disease. Because of the potential importance of GADD34 and CReP in aspects of human health and disease, we will discuss several pharmacological inhibitors of GADD34 and/or CReP that show promise as treatments and the controversies as to their mechanism of action. This review will finish with a discussion of the biochemical properties of GADD34 and CReP, their regulation and the additional interacting partners that may provide insight into the roles these proteins may play in other cellular pathways. We will conclude with a brief outline of critical areas for future study.
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Affiliation(s)
- Danielle Hicks
- Department of Science, Mathematics and Engineering, Modesto Junior College, Modesto, CA 95350, USA
- Department of Biological Sciences, University of the Pacific, Stockton, CA 95211, USA
| | - Krithika Giresh
- Department of Biological Sciences, University of the Pacific, Stockton, CA 95211, USA
| | - Lisa A. Wrischnik
- Department of Biological Sciences, University of the Pacific, Stockton, CA 95211, USA
| | - Douglas C. Weiser
- Department of Biological Sciences, University of the Pacific, Stockton, CA 95211, USA
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20
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Hein JB, Nguyen HT, Garvanska DH, Nasa I, Kruse T, Feng Y, Lopez Mendez B, Davey N, Kettenbach AN, Fordyce PM, Nilsson J. Phosphatase specificity principles uncovered by MRBLE:Dephos and global substrate identification. Mol Syst Biol 2023; 19:e11782. [PMID: 37916966 PMCID: PMC10698503 DOI: 10.15252/msb.202311782] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Revised: 10/14/2023] [Accepted: 10/16/2023] [Indexed: 11/03/2023] Open
Abstract
Phosphoprotein phosphatases (PPPs) regulate major signaling pathways, but the determinants of phosphatase specificity are poorly understood. This is because methods to investigate this at scale are lacking. Here, we develop a novel in vitro assay, MRBLE:Dephos, that allows multiplexing of dephosphorylation reactions to determine phosphatase preferences. Using MRBLE:Dephos, we establish amino acid preferences of the residues surrounding the dephosphorylation site for PP1 and PP2A-B55, which reveals common and unique preferences. To compare the MRBLE:Dephos results to cellular substrates, we focused on mitotic exit that requires extensive dephosphorylation by PP1 and PP2A-B55. We use specific inhibition of PP1 and PP2A-B55 in mitotic exit lysates coupled with phosphoproteomics to identify more than 2,000 regulated sites. Importantly, the sites dephosphorylated during mitotic exit reveal key signatures that are consistent with MRBLE:Dephos. Furthermore, integration of our phosphoproteomic data with mitotic interactomes of PP1 and PP2A-B55 provides insight into how binding of phosphatases to substrates shapes dephosphorylation. Collectively, we develop novel approaches to investigate protein phosphatases that provide insight into mitotic exit regulation.
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Affiliation(s)
- Jamin B Hein
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
- Department of BioengineeringStanford UniversityStanfordCAUSA
| | - Hieu T Nguyen
- Biochemistry and Cell BiologyGeisel School of Medicine at Dartmouth CollegeHanoverNHUSA
| | - Dimitriya H Garvanska
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Isha Nasa
- Department of BioengineeringStanford UniversityStanfordCAUSA
| | - Thomas Kruse
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Yinnian Feng
- Department of GeneticsStanford UniversityStanfordCAUSA
| | - Blanca Lopez Mendez
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Norman Davey
- Division of Cancer BiologyThe Institute of Cancer ResearchLondonUK
| | - Arminja N Kettenbach
- Biochemistry and Cell BiologyGeisel School of Medicine at Dartmouth CollegeHanoverNHUSA
| | - Polly M Fordyce
- Department of BioengineeringStanford UniversityStanfordCAUSA
- Department of GeneticsStanford UniversityStanfordCAUSA
- Sarafan ChEM‐HStanford UniversityStanfordCAUSA
- Chan Zuckerberg BiohubSan FranciscoCAUSA
| | - Jakob Nilsson
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
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21
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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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22
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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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23
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Gao S, Carrasquillo Rodríguez JW, Bahmanyar S, Airola MV. Structure and mechanism of the human CTDNEP1-NEP1R1 membrane protein phosphatase complex necessary to maintain ER membrane morphology. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.20.567952. [PMID: 38045299 PMCID: PMC10690229 DOI: 10.1101/2023.11.20.567952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
C-terminal Domain Nuclear Envelope Phosphatase 1 (CTDNEP1) is a non-canonical protein serine/threonine phosphatase that regulates ER membrane biogenesis. Inactivating mutations in CTDNEP1 correlate with development of medulloblastoma, an aggressive childhood cancer. The transmembrane protein Nuclear Envelope Phosphatase 1 Regulatory Subunit 1 (NEP1R1) binds CTDNEP1, but the molecular details by which NEP1R1 regulates CTDNEP1 function are unclear. Here, we find that knockdown of CTDNEP1 or NEP1R1 in human cells generate identical phenotypes, establishing CTDNEP1-NEP1R1 as an evolutionarily conserved membrane protein phosphatase complex that restricts ER expansion. Mechanistically, NEP1R1 acts as an activating regulatory subunit that directly binds and increases the phosphatase activity of CTDNEP1. By defining a minimal NEP1R1 domain sufficient to activate CTDNEP1, we determine high resolution crystal structures of the CTDNEP1-NEP1R1 complex bound to a pseudo-substrate. Structurally, NEP1R1 engages CTDNEP1 at a site distant from the active site to stabilize and allosterically activate CTDNEP1. Substrate recognition is facilitated by a conserved Arg residue that binds and orients the substrate peptide in the active site. Together, this reveals mechanisms for how NEP1R1 regulates CTDNEP1 and explains how cancer-associated mutations inactivate CTDNEP1.
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Affiliation(s)
- Shujuan Gao
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook NY 11794, USA
| | | | - Shirin Bahmanyar
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
| | - Michael V. Airola
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook NY 11794, USA
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24
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Henriques MC, Carvalho I, Santos C, Herdeiro MT, Fardilha M, Pavlaki MD, Loureiro S. Unveiling the molecular mechanisms and developmental consequences of mercury (Hg) toxicity in zebrafish embryo-larvae: A comprehensive approach. Neurotoxicol Teratol 2023; 100:107302. [PMID: 37739188 DOI: 10.1016/j.ntt.2023.107302] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 09/19/2023] [Accepted: 09/19/2023] [Indexed: 09/24/2023]
Abstract
Mercury (Hg) is a global contaminant affecting aquatic ecosystems' health. Chronic exposure to Hg has shown that the normal development of zebrafish embryo-larvae is affected. However, the molecular mechanisms behind the toxicity of Hg on fish embryonic development are still poorly understood. This work aimed to investigate the effects of Hg exposure on zebrafish embryo-larvae using a combined approach at individual (mortality, embryo development and locomotor behavior) and biochemical (neurotoxicity and oxidative stress enzymatic activities and protein phosphatase expression) levels. The Fish Embryo Toxicity assay followed the Organization for Economic Cooperation and Development Guideline 236 and used a concentration range between 13 and 401 μg Hg/L. Lethal and developmental endpoints were examined at 24, 48, 72 and 96 hpf. Biochemical markers, including Acetylcholinesterase (AChE), Catalase (CAT), Glutathione Reductase (GR), and Glutathione-S-Transferase (GST) activities and, for the first time, the expression of the protein phosphatase 1 gamma (PP1γ) was assessed after 24, 48, 72 and 96 h of exposure to 10 and 100 μg Hg/L. The behavioral effects of a sublethal range of Hg (from 0.8 to 13 μg Hg/L) were assessed using an automated video tracking system at 120 hpf. Several developmental abnormalities on zebrafish embryos and larvae, including pericardial edema, spin and tail deformities and reduced rate of consumption of the yolk sac, were found after exposure to Hg (LC50 at 96 hpf of 139 μg Hg/L) with EC50 values for total malformations ranging from 22 to 264 μg Hg/L. After 96 hpf, no significant effects were observed in the CAT and GR activities. However, an increase in the GST activity in a concentration and time-dependent manner was found, denoting possible stress-related adaptation of zebrafish embryos to deleterious effects of Hg exposure. The AchE activity showed a response pattern in line with the behavioral responses. At the lowest concentration tested, no significant effects were found for the AChE activity, whereas a decrease in AChE activity was observed at 100 μg Hg/L, suggesting that exposure to Hg induced neurotoxic effects in zebrafish embryos which in turn may explain the lack of equilibrium found in this study (EC50 at 96 hpf of 83 μg Hg/L). Moreover, a decrease in the PP1γ expression was found after 96 h of exposure to 10 and 100 μg Hg/L. Thus, we suggest that Hg may be an inhibitor of PP1γ in zebrafish embryos-larvae and thus, along with the alterations in the enzymatic activity of GST, explain some of the developmental malformations observed, as well as the lack of equilibrium. Hence, in this study, we propose the use of PP1 expression, in combination with apical and biochemical endpoints, as a precursor for assessing Hg's toxic mechanism on embryonic development.
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Affiliation(s)
- Magda Carvalho Henriques
- Institute of Biomedicine (iBiMED) & Department of Medical Sciences, University of Aveiro, Aveiro, Portugal; CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro, Portugal
| | - Inês Carvalho
- Department of Biology, University of Aveiro, Aveiro, Portugal
| | - Cátia Santos
- CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro, Portugal
| | - Maria Teresa Herdeiro
- Institute of Biomedicine (iBiMED) & Department of Medical Sciences, University of Aveiro, Aveiro, Portugal
| | - Margarida Fardilha
- Institute of Biomedicine (iBiMED) & Department of Medical Sciences, University of Aveiro, Aveiro, Portugal
| | - Maria Dimitriou Pavlaki
- CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro, Portugal.
| | - Susana Loureiro
- CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro, Portugal
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25
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Dedigama-Arachchige PM, Acharige NPN, Zhang X, Bremer HJ, Yi Z, Pflum MKH. Identification of PP1c-PPP1R12A Substrates Using Kinase-Catalyzed Biotinylation to Identify Phosphatase Substrates. ACS OMEGA 2023; 8:35628-35637. [PMID: 37810667 PMCID: PMC10552495 DOI: 10.1021/acsomega.3c01944] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 07/21/2023] [Indexed: 10/10/2023]
Abstract
Protein phosphatase 1 regulatory subunit 12A (PPP1R12A) interacts with the catalytic subunit of protein phosphatase 1 (PP1c) to form the myosin phosphatase complex. In addition to a well-documented role in muscle contraction, the PP1c-PPP1R12A complex is associated with cytoskeleton organization, cell migration and adhesion, and insulin signaling. Despite the variety of biological functions, only a few substrates of the PP1c-PPP1R12A complex are characterized, which limit a full understanding of PP1c-PPP1R12A activities in muscle contraction and cytoskeleton regulation. Here, the chemoproteomics method Kinase-catalyzed Biotinylation to Identify Phosphatase Substrates (K-BIPS) was used to identify substrates of the PP1c-PPP1R12A complex in L6 skeletal muscle cells. K-BIPS enriched 136 candidate substrates with 14 high confidence hits. One high confidence hit, AKT1 kinase, was validated as a novel PP1c-PPP1R12A substrate. Given the previously documented role of AKT1 in PPP1R12A phosphorylation and cytoskeleton organization, the data suggest that PP1c-PPP1R12A regulates its own phosphatase activity through an AKT1-dependent feedback mechanism to influence cytoskeletal arrangement in muscle cells.
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Affiliation(s)
| | - Nuwan P N Acharige
- Department of Chemistry, Wayne State University, 5101 Cass Ave, Detroit 48202-3489, Michigan, United States
| | - Xiangmin Zhang
- Department of Pharmaceutical Sciences, Wayne State University, 259 Mack Ave, Detroit 48201, Michigan, United States
| | - Hannah J Bremer
- Department of Chemistry, Wayne State University, 5101 Cass Ave, Detroit 48202-3489, Michigan, United States
| | - Zhengping Yi
- Department of Pharmaceutical Sciences, Wayne State University, 259 Mack Ave, Detroit 48201, Michigan, United States
| | - Mary Kay H Pflum
- Department of Chemistry, Wayne State University, 5101 Cass Ave, Detroit 48202-3489, Michigan, United States
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26
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Bonsor DA, Simanshu DK. Structural insights into the role of SHOC2-MRAS-PP1C complex in RAF activation. FEBS J 2023; 290:4852-4863. [PMID: 37074066 PMCID: PMC10584989 DOI: 10.1111/febs.16800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 04/07/2023] [Accepted: 04/18/2023] [Indexed: 04/20/2023]
Abstract
RAF activation is a key step for signalling through the mitogen-activated protein kinase (MAPK) pathway. The SHOC2 protein, along with MRAS and PP1C, forms a high affinity, heterotrimeric holoenzyme that activates RAF kinases by dephosphorylating a specific phosphoserine. Recently, our research, along with that of three other teams, has uncovered valuable structural and functional insights into the SHOC2-MRAS-PP1C (SMP) holoenzyme complex. In this structural snapshot, we review SMP complex assembly, the dependency on the bound-nucleotide state of MRAS, the substitution of MRAS by the canonical RAS proteins and the roles of SHOC2 and MRAS on PP1C activity and specificity. Furthermore, we discuss the effect of several RASopathy mutations identified within the SMP complex and explore potential therapeutic approaches for targeting the SMP complex in RAS/RAF-driven cancers and RASopathies.
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Affiliation(s)
- Daniel A. Bonsor
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Dhirendra K. Simanshu
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
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27
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Egbert JR, Silbern I, Uliasz TF, Lowther KM, Yee SP, Urlaub H, Jaffe LA. Phosphatases modified by LH signaling in ovarian follicles: testing their role in regulating the NPR2 guanylyl cyclase. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.12.544636. [PMID: 37333193 PMCID: PMC10274890 DOI: 10.1101/2023.06.12.544636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
In response to luteinizing hormone, multiple proteins in rat and mouse granulosa cells are rapidly dephosphorylated, but the responsible phosphatases remain to be identified. Because the phosphorylation state of phosphatases can regulate their interaction with substrates, we searched for phosphatases that might function in LH signaling by using quantitative mass spectrometry. We identified all proteins in rat ovarian follicles whose phosphorylation state changed detectably in response to a 30-minute exposure to LH, and within this list, identified protein phosphatases or phosphatase regulatory subunits that showed changes in phosphorylation. Phosphatases in the PPP family were of particular interest because of their requirement for dephosphorylating the natriuretic peptide receptor 2 (NPR2) guanylyl cyclase in the granulosa cells, which triggers oocyte meiotic resumption. Among the PPP family regulatory subunits, PPP1R12A and PPP2R5D showed the largest increases in phosphorylation, with 4-10 fold increases in signal intensity on several sites. Although follicles from mice in which these phosphorylations were prevented by serine-to-alanine mutations in either Ppp1r12a or Ppp2r5d showed normal LH-induced NPR2 dephosphorylation, these regulatory subunits and others could act redundantly to dephosphorylate NPR2. Our identification of phosphatases and other proteins whose phosphorylation state is rapidly modified by LH provides clues about multiple signaling pathways in ovarian follicles. Summary sentence Quantitative mass spectrometric analysis of phosphatases whose phosphorylation state is rapidly modified by luteinizing hormone provides clues about how LH signaling dephosphorylates NPR2 as well as a resource for future studies.
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Affiliation(s)
- Jeremy R. Egbert
- Department of Cell Biology, University of Connecticut Health Center, Farmington CT 06030 USA
| | - Ivan Silbern
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Multidisciplinary Sciences, 37077 Goettingen, Germany
- Institute of Clinical Chemistry, University Medical Center Goettingen, 37075 Goettingen, Germany
| | - Tracy F. Uliasz
- Department of Cell Biology, University of Connecticut Health Center, Farmington CT 06030 USA
| | - Katie M. Lowther
- Department of Cell Biology, University of Connecticut Health Center, Farmington CT 06030 USA
- Center for Mouse Genome Modification, University of Connecticut Health Center, Farmington CT 06030 USA
| | - Siu-Pok Yee
- Department of Cell Biology, University of Connecticut Health Center, Farmington CT 06030 USA
- Center for Mouse Genome Modification, University of Connecticut Health Center, Farmington CT 06030 USA
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Multidisciplinary Sciences, 37077 Goettingen, Germany
- Institute of Clinical Chemistry, University Medical Center Goettingen, 37075 Goettingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, 37075 Göttingen, Germany
| | - Laurinda A. Jaffe
- Department of Cell Biology, University of Connecticut Health Center, Farmington CT 06030 USA
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28
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Mariano NC, Rusin SF, Nasa I, Kettenbach AN. Inducible Protein Degradation as a Strategy to Identify Phosphoprotein Phosphatase 6 Substrates in RAS-Mutant Colorectal Cancer Cells. Mol Cell Proteomics 2023; 22:100614. [PMID: 37392812 PMCID: PMC10400926 DOI: 10.1016/j.mcpro.2023.100614] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 06/13/2023] [Accepted: 06/28/2023] [Indexed: 07/03/2023] Open
Abstract
Protein phosphorylation is an essential regulatory mechanism that controls most cellular processes, including cell cycle progression, cell division, and response to extracellular stimuli, among many others, and is deregulated in many diseases. Protein phosphorylation is coordinated by the opposing activities of protein kinases and protein phosphatases. In eukaryotic cells, most serine/threonine phosphorylation sites are dephosphorylated by members of the Phosphoprotein Phosphatase (PPP) family. However, we only know for a few phosphorylation sites which specific PPP dephosphorylates them. Although natural compounds such as calyculin A and okadaic acid inhibit PPPs at low nanomolar concentrations, no selective chemical PPP inhibitors exist. Here, we demonstrate the utility of endogenous tagging of genomic loci with an auxin-inducible degron (AID) as a strategy to investigate specific PPP signaling. Using Protein Phosphatase 6 (PP6) as an example, we demonstrate how rapidly inducible protein degradation can be employed to identify dephosphorylation sites and elucidate PP6 biology. Using genome editing, we introduce AID-tags into each allele of the PP6 catalytic subunit (PP6c) in DLD-1 cells expressing the auxin receptor Tir1. Upon rapid auxin-induced degradation of PP6c, we perform quantitative mass spectrometry-based proteomics and phosphoproteomics to identify PP6 substrates in mitosis. PP6 is an essential enzyme with conserved roles in mitosis and growth signaling. Consistently, we identify candidate PP6c-dependent dephosphorylation sites on proteins implicated in coordinating the mitotic cell cycle, cytoskeleton, gene expression, and mitogen-activated protein kinase (MAPK) and Hippo signaling. Finally, we demonstrate that PP6c opposes the activation of large tumor suppressor 1 (LATS1) by dephosphorylating Threonine 35 (T35) on Mps One Binder (MOB1), thereby blocking the interaction of MOB1 and LATS1. Our analyses highlight the utility of combining genome engineering, inducible degradation, and multiplexed phosphoproteomics to investigate signaling by individual PPPs on a global level, which is currently limited by the lack of tools for specific interrogation.
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Affiliation(s)
- Natasha C Mariano
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Scott F Rusin
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Isha Nasa
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA; Dartmouth Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, USA
| | - Arminja N Kettenbach
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA; Dartmouth Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, USA.
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Shi H, Kong R, Miao X, Gou L, Yin X, Ding Y, Cao X, Meng Q, Gu M, Suo F. Decreased PPP1R3G in pre-eclampsia impairs human trophoblast invasion and migration via Akt/MMP-9 signaling pathway. Exp Biol Med (Maywood) 2023; 248:1373-1382. [PMID: 37642261 PMCID: PMC10657594 DOI: 10.1177/15353702231182214] [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: 12/22/2022] [Accepted: 03/28/2023] [Indexed: 08/31/2023] Open
Abstract
Pre-eclampsia (PE) is a severe pregnancy complication characterized by impaired trophoblast invasion and spiral artery remodeling and can have serious consequences for both mother and child. Protein phosphatase 1 regulatory subunit 3G (PPP1R3G) is involved in numerous tumor-related biological processes. However, the biological action and underlying mechanisms of PPP1R3G in PE progression remain unclear. We used western blotting and immunohistochemistry to investigate PPP1R3G expression in gestational age-matched pre-eclamptic and normal placental tissues. After lentivirus transfection, wound-healing, Transwell, cell-counting kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), and TdT mediateddUTP Nick End Labeling (TUNEL) assays were used to assess trophoblast migration, invasion, proliferation, and apoptosis, respectively. The relative expression levels of PPP1R3G and the proteins involved in the Akt signaling pathway were determined using western blotting. The results showed that PPP1R3G levels were significantly lower in the placental tissues and GSE74341 microarray of the PE group than those of the healthy control group. We also found that neonatal weight and Apgar score were lower at birth, and peak systolic blood pressure and diastolic blood pressure were higher in the PE group than in the non-PE group. In addition, PPP1R3G knockdown decreased p-Akt/Akt expression and inhibited migration, invasion, and proliferation in HTR-8/SVneo trophoblasts but had no discernible effect on cell apoptosis. Furthermore, PPP1R3G positively regulated matrix metallopeptidase 9 (MMP-9), which was downregulated in placental tissues of pregnant women with PE. These results provided the first evidence that the reduced levels of PPP1R3G might contribute to PE by suppressing the invasion and migration of trophoblasts and targeting the Akt/MMP-9 signaling pathway.
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Affiliation(s)
- Huimin Shi
- Department of Obstetrics, Xuzhou Cancer Hospital, Xuzhou 221005, Jiangsu Province, China
| | - Renyu Kong
- Department of Cell Biology and Neurobiology, Xuzhou Key Laboratory of Neurobiology, Xuzhou Medical University, Xuzhou 221004, China
| | - Xu Miao
- Department of Cell Biology and Neurobiology, Xuzhou Key Laboratory of Neurobiology, Xuzhou Medical University, Xuzhou 221004, China
| | - Lingshan Gou
- Center for Genetic Medicine, Maternity and Child Health Care Hospital Affiliated to Xuzhou Medical University, 46 Heping Road, Xuzhou 221009, Jiangsu Province, China
| | - Xin Yin
- Center for Genetic Medicine, Maternity and Child Health Care Hospital Affiliated to Xuzhou Medical University, 46 Heping Road, Xuzhou 221009, Jiangsu Province, China
| | - Yuning Ding
- Department of Cell Biology and Neurobiology, Xuzhou Key Laboratory of Neurobiology, Xuzhou Medical University, Xuzhou 221004, China
| | - Xiliang Cao
- Department of Urology, Xuzhou No. 1 People’s Hospital, the Affiliated Xuzhou Municipal Hospital of Xuzhou Medical University, Xuzhou, Jiangsu Province, China
| | - Qingyong Meng
- Department of Obstetrics, Xuzhou Maternal and Child Health Hospital Affiliated to Xuzhou Medical University, Xuzhou 221009, Jiangsu Province, China
| | - Maosheng Gu
- Center for Genetic Medicine, Maternity and Child Health Care Hospital Affiliated to Xuzhou Medical University, 46 Heping Road, Xuzhou 221009, Jiangsu Province, China
| | - Feng Suo
- Center for Genetic Medicine, Maternity and Child Health Care Hospital Affiliated to Xuzhou Medical University, 46 Heping Road, Xuzhou 221009, Jiangsu Province, China
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Camlin NJ, Venkatachalam I, Evans JP. Oscillations in PP1 activity are essential for accurate progression through mammalian oocyte meiosis. Cell Cycle 2023; 22:1614-1636. [PMID: 37340734 PMCID: PMC10361142 DOI: 10.1080/15384101.2023.2225924] [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: 08/25/2022] [Revised: 04/17/2023] [Accepted: 06/12/2023] [Indexed: 06/22/2023] Open
Abstract
Tightly controlled fluctuations in kinase and phosphatase activity play important roles in regulating M-phase transitions. Protein Phosphatase 1 (PP1) is one of these phosphatases, with oscillations in PP1 activity driving mitotic M-phase. Evidence from a variety of experimental systems also points to roles in meiosis. Here, we report that PP1 is important for M-phase transitions through mouse oocyte meiosis. We employed a unique small-molecule approach to inhibit or activate PP1 at distinct phases of mouse oocyte meiosis. These studies show that temporal control of PP1 activity is essential for the G2/M transition, metaphase I/anaphase I transition, and the formation of a normal metaphase II oocyte. Our data also reveal that inappropriate activation of PP1 is more deleterious at the G2/M transition than at prometaphase I-to-metaphase I, and that an active pool of PP1 during prometaphase is vital for metaphase I/anaphase I transition and metaphase II chromosome alignment. Taken together, these results establish that loss of oscillations in PP1 activity causes a range of severe meiotic defects, pointing to essential roles for PP1 in female fertility, and more broadly, M-phase regulation.
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Affiliation(s)
- Nicole J. Camlin
- Department of Biological Sciences, Purdue University, West Lafayette, INUnited States
| | - Ilakkiya Venkatachalam
- Department of Biological Sciences, Purdue University, West Lafayette, INUnited States
- Department of Human Genetics, University of Michigan, Ann Arbor, MIUnited States
| | - Janice P. Evans
- Department of Biological Sciences, Purdue University, West Lafayette, INUnited States
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Ahmad A, Tigabu B, Ivanov A, Jerebtsova M, Ammosova T, Ramanathan P, Kumari N, Brantner CA, Pietzsch CA, Abdullah G, Popratiloff A, Widen S, Bukreyev A, Nekhai S. Ebola Virus NP Binding to Host Protein Phosphatase-1 Regulates Capsid Formation. RESEARCH SQUARE 2023:rs.3.rs-2963943. [PMID: 37333330 PMCID: PMC10274954 DOI: 10.21203/rs.3.rs-2963943/v1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
The Ebola virus (EBOV) transcriptional regulation involves host protein phosphatases PP1 and PP2A, which dephosphorylate the transcriptional cofactor of EBOV polymerase VP30. The 1E7-03 compound, which targets PP1, induces VP30 phosphorylation and inhibits EBOV infection. This study aimed to investigate the role of PP1 in EBOV replication. When EBOV-infected cells were continuously treated with 1E7-03, the NP E619K mutation was selected. This mutation moderately reduced EBOV minigenome transcription, which was restored by the treatment with 1E7-03. Formation of EBOV capsids, when NP was co-expressed with VP24 and VP35, was impaired with NPE 619K. Treatment with 1E7-03 restored capsid formation by NP E619K mutation, but inhibited capsids formed by WT NP. The dimerization of NP E619K, tested in a split NanoBiT assay, was significantly decreased (~ 15-fold) compared to WT NP. NP E619K bound more efficiently to PP1 (~ 3-fold) but not B56 subunit of PP2A or VP30. Cross-linking and co-immunoprecipitation experiments showed fewer monomers and dimers for NP E619K which were increased with 1E7-03 treatment. NP E619K showed increased co-localization with PP1α compared to WT NP. Mutations of potential PP1 binding sites and NP deletions disrupted its interaction with PP1. Collectively, our findings suggest that PP1 binding to the NP regulates NP dimerization and capsid formation, and that NP E619K mutation, which has the enhanced PP1 binding, disrupts these processes. Our results point to a new role for PP1 in EBOV replication in which NP binding to PP1 may facilitate viral transcription by delaying capsid formation and EBOV replication.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | - Steve Widen
- UTMB: The University of Texas Medical Branch at Galveston
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32
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Patil RS, Kovacs-Kasa A, Gorshkov BA, Fulton DJR, Su Y, Batori RK, Verin AD. Serine/Threonine Protein Phosphatases 1 and 2A in Lung Endothelial Barrier Regulation. Biomedicines 2023; 11:1638. [PMID: 37371733 PMCID: PMC10296329 DOI: 10.3390/biomedicines11061638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 05/28/2023] [Accepted: 06/02/2023] [Indexed: 06/29/2023] Open
Abstract
Vascular barrier dysfunction is characterized by increased permeability and inflammation of endothelial cells (ECs), which are prominent features of acute lung injury (ALI), acute respiratory distress syndrome (ARDS), and sepsis, and a major complication of the SARS-CoV-2 infection and COVID-19. Functional impairment of the EC barrier and accompanying inflammation arises due to microbial toxins and from white blood cells of the lung as part of a defensive action against pathogens, ischemia-reperfusion or blood product transfusions, and aspiration syndromes-based injury. A loss of barrier function results in the excessive movement of fluid and macromolecules from the vasculature into the interstitium and alveolae resulting in pulmonary edema and collapse of the architecture and function of the lungs, and eventually culminates in respiratory failure. Therefore, EC barrier integrity, which is heavily dependent on cytoskeletal elements (mainly actin filaments, microtubules (MTs), cell-matrix focal adhesions, and intercellular junctions) to maintain cellular contacts, is a critical requirement for the preservation of lung function. EC cytoskeletal remodeling is regulated, at least in part, by Ser/Thr phosphorylation/dephosphorylation of key cytoskeletal proteins. While a large body of literature describes the role of phosphorylation of cytoskeletal proteins on Ser/Thr residues in the context of EC barrier regulation, the role of Ser/Thr dephosphorylation catalyzed by Ser/Thr protein phosphatases (PPases) in EC barrier regulation is less documented. Ser/Thr PPases have been proposed to act as a counter-regulatory mechanism that preserves the EC barrier and opposes EC contraction. Despite the importance of PPases, our knowledge of the catalytic and regulatory subunits involved, as well as their cellular targets, is limited and under-appreciated. Therefore, the goal of this review is to discuss the role of Ser/Thr PPases in the regulation of lung EC cytoskeleton and permeability with special emphasis on the role of protein phosphatase 1 (PP1) and protein phosphatase 2A (PP2A) as major mammalian Ser/Thr PPases. Importantly, we integrate the role of PPases with the structural dynamics of the cytoskeleton and signaling cascades that regulate endothelial cell permeability and inflammation.
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Affiliation(s)
- Rahul S. Patil
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Anita Kovacs-Kasa
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Boris A. Gorshkov
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - David J. R. Fulton
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
- Department of Pharmacology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Yunchao Su
- Department of Pharmacology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Robert K. Batori
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Alexander D. Verin
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
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Christensen KR, Combs B, Richards C, Grabinski T, Alhadidy MM, Kanaan NM. Phosphomimetics at Ser199/Ser202/Thr205 in Tau Impairs Axonal Transport in Rat Hippocampal Neurons. Mol Neurobiol 2023; 60:3423-3438. [PMID: 36859689 PMCID: PMC10122714 DOI: 10.1007/s12035-023-03281-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 02/16/2023] [Indexed: 03/03/2023]
Abstract
Our understanding of the biological functions of the tau protein now includes its role as a scaffolding protein involved in signaling regulation, which also has implications for tau-mediated dysfunction and degeneration in Alzheimer's disease and other tauopathies. Recently, we found that pseudophosphorylation at sites linked to the pathology-associated AT8 phosphoepitope of tau disrupts normal fast axonal transport through a protein phosphatase 1 (PP1)-dependent pathway in squid axoplasm. Activation of the pathway and the resulting transport deficits required tau's N-terminal phosphatase-activating domain (PAD) and PP1 but the connection between tau and PP1 was not well defined. Here, we studied functional interactions between tau and PP1 isoforms and their effects on axonal transport in mammalian neurons. First, we found that wild-type tau interacted with PP1α and PP1γ primarily through its microtubule-binding repeat domain. Pseudophosphorylation of tau at S199/S202/T205 (psTau) increased PAD exposure, enhanced interactions with PP1γ, and increased active PP1γ levels in mammalian cells. Expression of psTau also significantly impaired axonal transport in primary rat hippocampal neurons. Deletion of PAD in psTau significantly reduced the interaction with PP1γ, eliminated increases of active PP1γ levels, and rescued axonal transport impairment in neurons. These data suggest that a functional consequence of phosphorylation within S199-T205 in tau, which occurs in AD and several other tauopathies, may be aberrant interaction with and activation of PP1γ and subsequent axonal transport disruption in a PAD-dependent fashion.
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Affiliation(s)
- Kyle R Christensen
- Department of Translational Neuroscience, Michigan State University, 400 Monroe Ave NW, Grand Rapids, MI, 49503, USA
- Neuroscience Program, Michigan State University, East Lansing, MI, 48824, USA
| | - Benjamin Combs
- Department of Translational Neuroscience, Michigan State University, 400 Monroe Ave NW, Grand Rapids, MI, 49503, USA
| | - Collin Richards
- Department of Translational Neuroscience, Michigan State University, 400 Monroe Ave NW, Grand Rapids, MI, 49503, USA
| | - Tessa Grabinski
- Department of Translational Neuroscience, Michigan State University, 400 Monroe Ave NW, Grand Rapids, MI, 49503, USA
| | - Mohammed M Alhadidy
- Department of Translational Neuroscience, Michigan State University, 400 Monroe Ave NW, Grand Rapids, MI, 49503, USA
- Neuroscience Program, Michigan State University, East Lansing, MI, 48824, USA
| | - Nicholas M Kanaan
- Department of Translational Neuroscience, Michigan State University, 400 Monroe Ave NW, Grand Rapids, MI, 49503, USA.
- Neuroscience Program, Michigan State University, East Lansing, MI, 48824, USA.
- Hauenstein Neuroscience Center, Mercy Health Saint Mary's, Grand Rapids, MI, 49503, USA.
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Wang B, He W, Huang M, Feng J, Li Y, Yu L, Wang Y, Zhou D, Meng C, Cheng D, Tang N, Song B, Chen H. Ralstonia solanacearum type III effector RipAS associates with potato type one protein phosphatase StTOPP6 to promote bacterial wilt. HORTICULTURE RESEARCH 2023; 10:uhad087. [PMID: 37334181 PMCID: PMC10273071 DOI: 10.1093/hr/uhad087] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 04/24/2023] [Indexed: 06/20/2023]
Abstract
The bacterial pathogen Ralstonia solanacearum (R. solanacearum) delivered type III secretion effectors to inhibit the immune system and cause bacterial wilt on potato. Protein phosphatases are key regulators in plant immunity, which pathogens can manipulate to alter host processes. Here, we show that a type III effector RipAS can reduce the nucleolar accumulation of a type one protein phosphatase (PP1) StTOPP6 to promote bacterial wilt. StTOPP6 was used as bait in the Yeast two-Hybrid (Y2H) assay and acquired an effector RipAS that interacts with it. RipAS was characterized as a virulence effector to contribute to R. solanacearum infection, and stable expression of RipAS in potato impaired plant resistance against R. solanacearum. Overexpression of StTOPP6 showed enhanced disease symptoms when inoculated with wild strain UW551 but not the ripAS deletion mutant, indicating that the expression of StTOPP6 facilitates the virulence of RipAS. RipAS reduced the nucleolar accumulation of StTOPP6, which occurred during R. solanacearum infection. Moreover, the association also widely existed between other PP1s and RipAS. We argue that RipAS is a virulence effector associated with PP1s to promote bacterial wilt.
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Affiliation(s)
- Bingsen Wang
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan 430070, China
- Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Wuhan 430070, China
- Potato Engineering and Technology Research Center of Hubei Province, Huazhong Agricultural University, Wuhan 430070, China
- College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan 430070, China
| | - Wenfeng He
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan 430070, China
- Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Wuhan 430070, China
- Potato Engineering and Technology Research Center of Hubei Province, Huazhong Agricultural University, Wuhan 430070, China
- College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan 430070, China
| | - Mengshu Huang
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan 430070, China
- Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Wuhan 430070, China
- Potato Engineering and Technology Research Center of Hubei Province, Huazhong Agricultural University, Wuhan 430070, China
- College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan 430070, China
| | - Jiachen Feng
- State Key Laboratory of Crop Stress Adaptation and Improvement, Henan University, Kaifeng 475001, China
| | - Yanping Li
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan 430070, China
- Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Wuhan 430070, China
- Potato Engineering and Technology Research Center of Hubei Province, Huazhong Agricultural University, Wuhan 430070, China
- College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan 430070, China
| | - Liu Yu
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan 430070, China
- Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Wuhan 430070, China
- Potato Engineering and Technology Research Center of Hubei Province, Huazhong Agricultural University, Wuhan 430070, China
- College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan 430070, China
| | - Yuqi Wang
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan 430070, China
- Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Wuhan 430070, China
- Potato Engineering and Technology Research Center of Hubei Province, Huazhong Agricultural University, Wuhan 430070, China
- College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan 430070, China
| | - Dan Zhou
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan 430070, China
- Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Wuhan 430070, China
- Potato Engineering and Technology Research Center of Hubei Province, Huazhong Agricultural University, Wuhan 430070, China
- College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan 430070, China
| | - Chengzhen Meng
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan 430070, China
- Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Wuhan 430070, China
- Potato Engineering and Technology Research Center of Hubei Province, Huazhong Agricultural University, Wuhan 430070, China
- College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan 430070, China
| | - Dong Cheng
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan 430070, China
- Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Wuhan 430070, China
- Potato Engineering and Technology Research Center of Hubei Province, Huazhong Agricultural University, Wuhan 430070, China
- College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan 430070, China
| | - Ning Tang
- State Key Laboratory of Crop Stress Adaptation and Improvement, Henan University, Kaifeng 475001, China
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Srivastava G, Choy MS, Bolik-Coulon N, Page R, Peti W. Inhibitor-3 inhibits Protein Phosphatase 1 via a metal binding dynamic protein-protein interaction. Nat Commun 2023; 14:1798. [PMID: 37002212 PMCID: PMC10066265 DOI: 10.1038/s41467-023-37372-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 02/21/2023] [Indexed: 04/03/2023] Open
Abstract
To achieve substrate specificity, protein phosphate 1 (PP1) forms holoenzymes with hundreds of regulatory and inhibitory proteins. Inhibitor-3 (I3) is an ancient inhibitor of PP1 with putative roles in PP1 maturation and the regulation of PP1 activity. Here, we show that I3 residues 27-68 are necessary and sufficient for PP1 binding and inhibition. In addition to a canonical RVxF motif, which is shared by nearly all PP1 regulators and inhibitors, and a non-canonical SILK motif, I3 also binds PP1 via multiple basic residues that bind directly in the PP1 acidic substrate binding groove, an interaction that provides a blueprint for how substrates bind this groove for dephosphorylation. Unexpectedly, this interaction positions a CCC (cys-cys-cys) motif to bind directly across the PP1 active site. Using biophysical and inhibition assays, we show that the I3 CCC motif binds and inhibits PP1 in an unexpected dynamic, fuzzy manner, via transient engagement of the PP1 active site metals. Together, these data not only provide fundamental insights into the mechanisms by which IDP protein regulators of PP1 achieve inhibition, but also shows that fuzzy interactions between IDPs and their folded binding partners, in addition to enhancing binding affinity, can also directly regulate enzyme activity.
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Affiliation(s)
- Gautam Srivastava
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT, USA
| | - Meng S Choy
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT, USA
| | - Nicolas Bolik-Coulon
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA
| | - Rebecca Page
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT, USA
| | - Wolfgang Peti
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT, USA.
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Mariano NC, Rusin SF, Nasa I, Kettenbach AN. Inducible protein degradation as a strategy to identify Phosphoprotein Phosphatase 6 substrates in RAS-mutant colorectal cancer cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.25.534211. [PMID: 36993243 PMCID: PMC10055397 DOI: 10.1101/2023.03.25.534211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/13/2023]
Abstract
Protein phosphorylation is an essential regulatory mechanism that controls most cellular processes, including cell cycle progression, cell division, and response to extracellular stimuli, among many others, and is deregulated in many diseases. Protein phosphorylation is coordinated by the opposing activities of protein kinases and protein phosphatases. In eukaryotic cells, most serine/threonine phosphorylation sites are dephosphorylated by members of the Phosphoprotein Phosphatase (PPP) family. However, we only know for a few phosphorylation sites which specific PPP dephosphorylates them. Although natural compounds such as calyculin A and okadaic acid inhibit PPPs at low nanomolar concentrations, no selective chemical PPP inhibitors exist. Here, we demonstrate the utility of endogenous tagging of genomic loci with an auxin-inducible degron (AID) as a strategy to investigate specific PPP signaling. Using Protein Phosphatase 6 (PP6) as an example, we demonstrate how rapidly inducible protein degradation can be employed to identify dephosphorylation SITES and elucidate PP6 biology. Using genome editing, we introduce AID-tags into each allele of the PP6 catalytic subunit (PP6c) in DLD-1 cells expressing the auxin receptor Tir1. Upon rapid auxin-induced degradation of PP6c, we perform quantitative mass spectrometry-based proteomics and phosphoproteomics to identify PP6 substrates in mitosis. PP6 is an essential enzyme with conserved roles in mitosis and growth signaling. Consistently, we identify candidate PP6c-dependent phosphorylation sites on proteins implicated in coordinating the mitotic cell cycle, cytoskeleton, gene expression, and mitogen-activated protein kinase (MAPK) and Hippo signaling. Finally, we demonstrate that PP6c opposes the activation of large tumor suppressor 1 (LATS1) by dephosphorylating Threonine 35 (T35) on Mps One Binder (MOB1), thereby blocking the interaction of MOB1 and LATS1. Our analyses highlight the utility of combining genome engineering, inducible degradation, and multiplexed phosphoproteomics to investigate signaling by individual PPPs on a global level, which is currently limited by the lack of tools for specific interrogation.
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37
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Borchel A, Eichner C, Øvergård AC. Mining Lepeophtheirus salmonis RNA-Seq data for qPCR reference genes and their application in Caligus elongatus. Exp Parasitol 2023; 248:108511. [PMID: 36921884 DOI: 10.1016/j.exppara.2023.108511] [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: 01/30/2023] [Revised: 03/10/2023] [Accepted: 03/11/2023] [Indexed: 03/14/2023]
Abstract
Lepeophtheirus salmonis and Caligus elongatus are two parasitic copepod species posing a significant threat to salmonid aquaculture. Consequently, several gene expression studies are executed each year to gain new knowledge and treatment strategies. Though, to enable accurate gene expression measurements by quantitative real time PCR, stable reference genes are needed. Previous studies have mainly focused on a few genes selected based on their function as housekeeping genes, as these are often stably expressed in various cells and tissues. In the present study, however, RNA-sequencing data from 127 L. salmonis samples from different life stages and diverse environmental conditions were used to identify new candidate reference genes displaying low variation. From this, six genes were selected, and the stability validated by qPCR on samples from different life stages. Since neither a genome nor comprehensive RNA sequencing data are available for C. elongatus, homologous genes to those identified for L. salmonis were identified within a C. elongatus transcriptome assembly and validated by qPCR in different life stages. Overall, the genes eukaryotic translation initiation factor 1A (EIF1A) and serine/threonine-protein phosphatase 1 (PP1) displayed the highest stability in L. salmonis, while the combination of PP1 and ribosomal protein S13 (RPS13) was found to have the highest stability in C. elongatus. These genes are well-suited reference genes for qPCR applications which allow for accurate normalization of target genes.
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Affiliation(s)
- Andreas Borchel
- University of Bergen, SLRC-Sea Lice Research Centre, Department of Biological Sciences, Pb. 7803, 5020, Bergen, Norway.
| | - Christiane Eichner
- University of Bergen, SLRC-Sea Lice Research Centre, Department of Biological Sciences, Pb. 7803, 5020, Bergen, Norway
| | - Aina-Cathrine Øvergård
- University of Bergen, SLRC-Sea Lice Research Centre, Department of Biological Sciences, Pb. 7803, 5020, Bergen, Norway
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Phosphorylated Peptide Derived from the Myosin Phosphatase Target Subunit Is a Novel Inhibitor of Protein Phosphatase-1. Int J Mol Sci 2023; 24:ijms24054789. [PMID: 36902219 PMCID: PMC10003451 DOI: 10.3390/ijms24054789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/20/2023] [Accepted: 02/27/2023] [Indexed: 03/06/2023] Open
Abstract
Identification of specific protein phosphatase-1 (PP1) inhibitors is of special importance regarding the study of its cellular functions and may have therapeutic values in diseases coupled to signaling processes. In this study, we prove that a phosphorylated peptide of the inhibitory region of myosin phosphatase (MP) target subunit (MYPT1), R690QSRRS(pT696)QGVTL701 (P-Thr696-MYPT1690-701), interacts with and inhibits the PP1 catalytic subunit (PP1c, IC50 = 3.84 µM) and the MP holoenzyme (Flag-MYPT1-PP1c, IC50 = 3.84 µM). Saturation transfer difference NMR measurements established binding of hydrophobic and basic regions of P-Thr696-MYPT1690-701 to PP1c, suggesting interactions with the hydrophobic and acidic substrate binding grooves. P-Thr696-MYPT1690-701 was dephosphorylated by PP1c slowly (t1/2 = 81.6-87.9 min), which was further impeded (t1/2 = 103 min) in the presence of the phosphorylated 20 kDa myosin light chain (P-MLC20). In contrast, P-Thr696-MYPT1690-701 (10-500 µM) slowed down the dephosphorylation of P-MLC20 (t1/2 = 1.69 min) significantly (t1/2 = 2.49-10.06 min). These data are compatible with an unfair competition mechanism between the inhibitory phosphopeptide and the phosphosubstrate. Docking simulations of the PP1c-P-MYPT1690-701 complexes with phosphothreonine (PP1c-P-Thr696-MYPT1690-701) or phosphoserine (PP1c-P-Ser696-MYPT1690-701) suggested their distinct poses on the surface of PP1c. In addition, the arrangements and distances of the surrounding coordinating residues of PP1c around the phosphothreonine or phosphoserine at the active site were distinct, which may account for their different hydrolysis rate. It is presumed that P-Thr696-MYPT1690-701 binds tightly at the active center but the phosphoester hydrolysis is less preferable compared to P-Ser696-MYPT1690-701 or phosphoserine substrates. Moreover, the inhibitory phosphopeptide may serve as a template to synthesize cell permeable PP1-specific peptide inhibitors.
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Lin X, Ahmad A, Ivanov AI, Simhadri J, Wang S, Kumari N, Ammosova T, Nekhai S. HIV-1 Transcription Inhibitor 1E7-03 Decreases Nucleophosmin Phosphorylation. Mol Cell Proteomics 2023; 22:100488. [PMID: 36563749 PMCID: PMC9975258 DOI: 10.1016/j.mcpro.2022.100488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 12/07/2022] [Accepted: 12/18/2022] [Indexed: 12/25/2022] Open
Abstract
Transcription activation of latent human immunodeficiency virus-1 (HIV-1) occurs due to HIV-1 rebound, the interruption of combination antiretroviral therapy, or development of drug resistance. Thus, novel HIV-1 inhibitors, targeting HIV-1 transcription are needed. We previously developed an HIV-1 transcription inhibitor, 1E7-03, that binds to the noncatalytic RVxF-accommodating site of protein phosphatase 1 and inhibits HIV-1 replication in cultured cells and HIV-1-infected humanized mice by impeding protein phosphatase 1 interaction with HIV-1 Tat protein. However, host proteins and regulatory pathways targeted by 1E7-03 that contribute to its overall HIV-1 inhibitory activity remain to be identified. To address this issue, we performed label-free quantitative proteome and phosphoproteome analyses of noninfected and HIV-1-infected CEM T cells that were untreated or treated with 1E7-03. 1E7-03 significantly reprogramed the phosphorylation profile of proteins including PPARα/RXRα, TGF-β, and PKR pathways. Phosphorylation of nucleophosmin (NPM1) at Ser-125 residue in PPARα/RXRα pathway was significantly reduced (>20-fold, p = 1.37 × 10-9), followed by the reduced phosphorylation of transforming growth factor-beta 2 at Ser-46 (TGF-β2, >12-fold, p = 1.37 × 10-3). Downregulation of NPM1's Ser-125 phosphorylation was further confirmed using Western blot. Phosphorylation mimicking NPM1 S125D mutant activated Tat-induced HIV-1 transcription and exhibited enhanced NPM1-Tat interaction compared to NPM1 S125A mutant. Inhibition of Aurora A or Aurora B kinases that phosphorylate NPM1 on Ser-125 residue inhibited HIV-1, further supporting the role of NPM1 in HIV-1 infection. Taken together, 1E7-03 reprogrammed PPARα/RXRα and TGF-β pathways that contribute to the inhibition of HIV-1 transcription. Our findings suggest that NPM1 phosphorylation is a plausible target for HIV-1 transcription inhibition.
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Key Words
- actn4, alpha-actinin-1
- asl, argininosuccinate lyase
- aspm, abnormal spindle-like microcephaly-associated protein
- cart, combination antiretroviral therapy
- cdk2, cell cycle-dependent kinase 2
- ck2, casein kinase 2
- dmso, dimethyl sulfoxide
- egln1, egl-9 family hypoxia inducible factor 1
- erk/p38, extracellular signal-regulated kinase p38
- fa, formic acid
- gadd34, growth arrest and dna damage-inducible protein
- hif-1α, hypoxia-inducible factor 1α
- hiv-1 vif protein, viral infectivity factor, an hiv-1 accessory protein
- hiv-1, human immunodeficiency virus-1
- hsp90, heat shock protein 90
- ipa, ingenuity pathway analysis
- lc-ft/ms, tandem liquid chromatography-fourier transform mass spectrometry
- mapk, mitogen-activated protein kinase
- map3k4, mitogen-activated protein kinase kinase kinase 4
- mita, mediator of interferon response factor 3 activation
- nfat, nuclear factor of activated t cells
- nf-κb, nuclear factor kappa-light-chain-enhancer of activated b cell
- npm1, nucleophosmin
- oa, okadaic acid
- pi3k/akt, phosphoinositide 3-kinase/ ak strain transforming or protein kinase b
- pp, protein phosphatase
- pparα/rxrα, peroxisome proliferator-activated receptor α/ retinoid x receptor α
- ptm, posttranslational modification
- rnr2, ribonucleotide reductase 2
- rt, reverse transcription
- samhd1, sam domain and hd domain-containing protein 1
- smad7, mothers against decapentaplegic homolog 7
- stat5, signal transducer and activator of transcription 5 taf4
- taf4, transcription factor tfiid subunit tata-box-binding protein (tbp)-associated factor 4
- tgf-β2, transforming growth factor-beta
- tp53, tumor protein p53
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Affiliation(s)
- Xionghao Lin
- Center for Sickle Cell Disease, College of Medicine, Howard University, Washington, District of Columbia, USA; College of Dentistry, Howard University, Washington, District of Columbia, USA
| | - Asrar Ahmad
- Center for Sickle Cell Disease, College of Medicine, Howard University, Washington, District of Columbia, USA
| | - Andrey I Ivanov
- Center for Sickle Cell Disease, College of Medicine, Howard University, Washington, District of Columbia, USA
| | - Jyothirmai Simhadri
- Center for Sickle Cell Disease, College of Medicine, Howard University, Washington, District of Columbia, USA
| | - Songping Wang
- Center for Sickle Cell Disease, College of Medicine, Howard University, Washington, District of Columbia, USA
| | - Namita Kumari
- Center for Sickle Cell Disease, College of Medicine, Howard University, Washington, District of Columbia, USA; Department of Microbiology, College of Medicine, Howard University, Washington, District of Columbia, USA
| | - Tatiana Ammosova
- Center for Sickle Cell Disease, College of Medicine, Howard University, Washington, District of Columbia, USA; Department of Medicine, College of Medicine, Howard University, Washington, District of Columbia, USA
| | - Sergei Nekhai
- Center for Sickle Cell Disease, College of Medicine, Howard University, Washington, District of Columbia, USA; Department of Microbiology, College of Medicine, Howard University, Washington, District of Columbia, USA; Department of Medicine, College of Medicine, Howard University, Washington, District of Columbia, USA.
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Liaisons dangereuses: Intrinsic Disorder in Cellular Proteins Recruited to Viral Infection-Related Biocondensates. Int J Mol Sci 2023; 24:ijms24032151. [PMID: 36768473 PMCID: PMC9917183 DOI: 10.3390/ijms24032151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 01/11/2023] [Accepted: 01/19/2023] [Indexed: 01/25/2023] Open
Abstract
Liquid-liquid phase separation (LLPS) is responsible for the formation of so-called membrane-less organelles (MLOs) that are essential for the spatio-temporal organization of the cell. Intrinsically disordered proteins (IDPs) or regions (IDRs), either alone or in conjunction with nucleic acids, are involved in the formation of these intracellular condensates. Notably, viruses exploit LLPS at their own benefit to form viral replication compartments. Beyond giving rise to biomolecular condensates, viral proteins are also known to partition into cellular MLOs, thus raising the question as to whether these cellular phase-separating proteins are drivers of LLPS or behave as clients/regulators. Here, we focus on a set of eukaryotic proteins that are either sequestered in viral factories or colocalize with viral proteins within cellular MLOs, with the primary goal of gathering organized, predicted, and experimental information on these proteins, which constitute promising targets for innovative antiviral strategies. Using various computational approaches, we thoroughly investigated their disorder content and inherent propensity to undergo LLPS, along with their biological functions and interactivity networks. Results show that these proteins are on average, though to varying degrees, enriched in disorder, with their propensity for phase separation being correlated, as expected, with their disorder content. A trend, which awaits further validation, tends to emerge whereby the most disordered proteins serve as drivers, while more ordered cellular proteins tend instead to be clients of viral factories. In light of their high disorder content and their annotated LLPS behavior, most proteins in our data set are drivers or co-drivers of molecular condensation, foreshadowing a key role of these cellular proteins in the scaffolding of viral infection-related MLOs.
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Mehta V, Decan N, Ooi S, Gaudreau-Lapierre A, Copeland JW, Trinkle-Mulcahy L. SPECC1L binds the myosin phosphatase complex MYPT1/PP1β and can regulate its distribution between microtubules and filamentous actin. J Biol Chem 2023; 299:102893. [PMID: 36634848 PMCID: PMC9929477 DOI: 10.1016/j.jbc.2023.102893] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 12/19/2022] [Accepted: 12/21/2022] [Indexed: 01/11/2023] Open
Abstract
The subcellular localization, activity , and substrate specificity of the serine/threonine protein phosphatase 1 catalytic subunit (PP1cat) is mediated through its dynamic association with regulatory subunits in holoenzyme complexes. While some functional overlap is observed for the three human PP1cat isoforms, they also show distinct targeting based on relative preferences for specific regulatory subunits. A well-known example is the preferential association of MYPT1 with PP1β in the myosin phosphatase complex. In smooth muscle, MYPT1/PP1β counteracts the muscle contraction induced by phosphorylation of the light chains of myosin by the myosin light chain kinase. This phosphatase complex is also found in nonmuscle cells, where it is targeted to both myosin and nonmyosin substrates and contributes to regulation of the balance of cytoskeletal structure and motility during cell migration and division. Although it remains unclear how MYPT1/PP1β traffics between microtubule- and actin-associated substrates, our identification of the microtubule- and actin-binding protein SPECC1L in both the PP1β and MYPT1 interactomes suggests that it is the missing link. Our validation of their association using coimmunoprecipitation and proximity biotinylation assays, together with the strong overlap that we observed for the SPECC1L and MYPT1 interactomes, confirmed that they exist in a stable complex in the cell. We further showed that SPECC1L binds MYPT1 directly and that it can impact the balance of the distribution of the MYPT1/PP1β complex between the microtubule and filamentous actin networks.
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Affiliation(s)
- Virja Mehta
- Department of Cellular and Molecular Medicine, University of Ottawa, Faculty of Medicine, Ottawa, Canada,Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Canada
| | - Nathalie Decan
- Department of Cellular and Molecular Medicine, University of Ottawa, Faculty of Medicine, Ottawa, Canada,Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Canada
| | - Sarah Ooi
- Department of Cellular and Molecular Medicine, University of Ottawa, Faculty of Medicine, Ottawa, Canada,Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Canada
| | - Antoine Gaudreau-Lapierre
- Department of Cellular and Molecular Medicine, University of Ottawa, Faculty of Medicine, Ottawa, Canada,Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Canada
| | - John W. Copeland
- Department of Cellular and Molecular Medicine, University of Ottawa, Faculty of Medicine, Ottawa, Canada
| | - Laura Trinkle-Mulcahy
- Department of Cellular and Molecular Medicine, University of Ottawa, Faculty of Medicine, Ottawa, Canada; Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Canada.
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Saini LK, Bheri M, Pandey GK. Protein phosphatases and their targets: Comprehending the interactions in plant signaling pathways. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2023; 134:307-370. [PMID: 36858740 DOI: 10.1016/bs.apcsb.2022.11.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Protein phosphorylation is a vital reversible post-translational modification. This process is established by two classes of enzymes: protein kinases and protein phosphatases. Protein kinases phosphorylate proteins while protein phosphatases dephosphorylate phosphorylated proteins, thus, functioning as 'critical regulators' in signaling pathways. The eukaryotic protein phosphatases are classified as phosphoprotein phosphatases (PPP), metallo-dependent protein phosphatases (PPM), protein tyrosine (Tyr) phosphatases (PTP), and aspartate (Asp)-dependent phosphatases. The PPP and PPM families are serine (Ser)/threonine (Thr) specific phosphatases (STPs) that dephosphorylate Ser and Thr residues. The PTP family dephosphorylates Tyr residues while dual-specificity phosphatases (DsPTPs/DSPs) dephosphorylate Ser, Thr, and Tyr residues. The composition of these enzymes as well as their substrate specificity are important determinants of their functional significance in a number of cellular processes and stress responses. Their role in animal systems is well-understood and characterized. The functional characterization of protein phosphatases has been extensively covered in plants, although the comprehension of their mechanistic basis is an ongoing pursuit. The nature of their interactions with other key players in the signaling process is vital to our understanding. The substrates or targets determine their potential as well as magnitude of the impact they have on signaling pathways. In this article, we exclusively overview the various substrates of protein phosphatases in plant signaling pathways, which are a critical determinant of the outcome of various developmental and stress stimuli.
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Affiliation(s)
- Lokesh K Saini
- Department of Plant Molecular Biology, University of Delhi South Campus, Dhaula Kuan, New Delhi, India
| | - Malathi Bheri
- Department of Plant Molecular Biology, University of Delhi South Campus, Dhaula Kuan, New Delhi, India
| | - Girdhar K Pandey
- Department of Plant Molecular Biology, University of Delhi South Campus, Dhaula Kuan, New Delhi, India.
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Al-Huseini I, Sirasanagandla SR, Babu KS, Sofin RGS, Das S. Kinase Inhibitors Involved in the Regulation of Autophagy: Molecular Concepts and Clinical Implications. Curr Med Chem 2023; 30:1502-1528. [PMID: 35078392 DOI: 10.2174/0929867329666220117114306] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/08/2021] [Accepted: 11/22/2021] [Indexed: 11/22/2022]
Abstract
All cells and intracellular components are remodeled and recycled in order to replace the old and damaged cells. Autophagy is a process by which damaged, and unwanted cells are degraded in the lysosomes. There are three different types of autophagy: macroautophagy, microautophagy, and chaperone-mediated autophagy. Autophagy has an effect on adaptive and innate immunity, suppression of any tumour, and the elimination of various microbial pathogens. The process of autophagy has both positive and negative effects, and this pertains to any specific disease or its stage of progression. Autophagy involves various processes which are controlled by various signaling pathways, such as Jun N-terminal kinase, GSK3, ERK1, Leucine-rich repeat kinase 2, and PTEN-induced putative kinase 1 and parkin RBR E3. Protein kinases are also important for the regulation of autophagy as they regulate the process of autophagy either by activation or inhibition. The present review discusses the kinase catalyzed phosphorylated reactions, the kinase inhibitors, types of protein kinase inhibitors and their binding properties to protein kinase domains, the structures of active and inactive kinases, and the hydrophobic spine structures in active and inactive protein kinase domains. The intervention of autophagy by targeting specific kinases may form the mainstay of treatment of many diseases and lead the road to future drug discovery.
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Affiliation(s)
- Isehaq Al-Huseini
- Department of Physiology, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat, Al-Khodh 123, Oman
| | - Srinivasa Rao Sirasanagandla
- Department of Human and Clinical Anatomy, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat, Al-Khodh 123, Oman
| | - Kondaveeti Suresh Babu
- Department of Biochemistry, Symbiosis Medical College for Women, Symbiosis International (Deemed) University, Pune, Maharashtra, India
| | | | - Srijit Das
- Department of Human and Clinical Anatomy, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat, Al-Khodh 123, Oman
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Chojnacki JE, Scheinost L, Wang Y, Köhn M. Membrane targeting with palmitoylated lysine added to PP1-disrupting peptide induces PP1-independent signaling. J Pept Sci 2022; 29:e3469. [PMID: 36525306 DOI: 10.1002/psc.3469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/27/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022]
Abstract
Protein phosphatase-1 (PP1) is a ubiquitous enzyme involved in multiple processes inside cells. PP1-disrupting peptides (PDPs) are chemical tools that selectively bind to PP1 and release its activity. To restrict the activity of PDPs to a cellular compartment, we developed PDP-Mem, a cell membrane-targeting PDP. The membrane localization was achieved through the introduction of a palmitoylated lysine. PDP-Mem was shown to activate PP1α in vitro and to localize to the membrane of HeLa Kyoto and U2OS cells. However, in cells, the combination of the polybasic sequence for cell penetration and the membrane targeting palmitoylated lysine activates the MAPK signaling pathway and induces cytoplasmic calcium release independently of PP1 activation. Therefore, when targeting peptides to cellular membranes, undesired effects induced by the targeting sequence and lipid modification need to be considered.
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Affiliation(s)
- Jeremy E Chojnacki
- Faculty of Biology and Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.,Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Laura Scheinost
- Faculty of Biology and Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany
| | - Yansong Wang
- Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Maja Köhn
- Faculty of Biology and Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.,Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
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The ribosomal RNA processing 1B:protein phosphatase 1 holoenzyme reveals non-canonical PP1 interaction motifs. Cell Rep 2022; 41:111726. [PMID: 36450254 PMCID: PMC9813921 DOI: 10.1016/j.celrep.2022.111726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 09/20/2022] [Accepted: 11/03/2022] [Indexed: 12/03/2022] Open
Abstract
The serine/threonine protein phosphatase 1 (PP1) dephosphorylates hundreds of substrates by associating with >200 regulatory proteins to form specific holoenzymes. The major PP1 targeting protein in the nucleolus is RRP1B (ribosomal RNA processing 1B). In addition to selectively recruiting PP1β/PP1γ to the nucleolus, RRP1B also has a key role in ribosome biogenesis, among other functions. How RRP1B binds PP1 and regulates nucleolar phosphorylation signaling is not yet known. Here, we show that RRP1B recruits PP1 via established (RVxF/SILK/ΦΦ) and non-canonical motifs. These atypical interaction sites, the PP1β/γ specificity, and N-terminal AF-binding pockets rely on hydrophobic interactions that contribute to binding and, via phosphorylation, regulate complex formation. This work advances our understanding of PP1 isoform selectivity, reveals key roles of N-terminal PP1 residues in regulator binding, and suggests that additional PP1 interaction sites have yet to be identified, all of which are necessary for a systems biology understanding of PP1 function.
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Picard JY, Morin G, Devouassoux-Shisheboran M, Van der Smagt J, Klosowski S, Pienkowski C, Pierre-Renoult P, Masson C, Bole C, Josso N. Persistent Müllerian duct syndrome associated with genetic defects in the regulatory subunit of myosin phosphatase. Hum Reprod 2022; 37:2952-2959. [PMID: 36331510 DOI: 10.1093/humrep/deac239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 09/29/2022] [Indexed: 11/06/2022] Open
Abstract
STUDY QUESTION Can mutations of genes other than AMH or AMHR2, namely PPP1R12A coding myosin phosphatase, lead to persistent Müllerian duct syndrome (PMDS)? SUMMARY ANSWER The detection of PPP1R12A truncation mutations in five cases of PMDS suggests that myosin phosphatase is involved in Müllerian regression, independently of the anti-Müllerian hormone (AMH) signaling cascade. WHAT IS KNOWN ALREADY Mutations of AMH and AMHR2 are detectable in an overwhelming majority of PMDS patients but in 10% of cases, both genes are apparently normal, suggesting that other genes may be involved. STUDY DESIGN, SIZE, DURATION DNA samples from 39 PMDS patients collected from 1990 to present, in which Sanger sequencing had failed to detect biallelic AMH or AMHR2 mutations, were screened by massive parallel sequencing. PARTICIPANTS/MATERIALS, SETTING, METHODS To rule out the possibility that AMH or AMHR2 mutations could have been missed, all DNA samples of good quality were analyzed by targeted next-generation sequencing. Twenty-four samples in which the absence of AMH or AMHR2 biallelic mutations was confirmed were subjected to whole-exome sequencing with the aim of detecting variants of other genes potentially involved in PMDS. MAIN RESULTS AND THE ROLE OF CHANCE Five patients out of 24 (21%) harbored deleterious truncation mutations of PP1R12A, the gene coding for the regulatory subunit of myosin phosphatase, were detected. In addition to PMDS, three of these patients presented with ileal and one with esophageal atresia. The congenital abnormalities associated with PMDS in our patients are consistent with those described in the literature for PPP1R12A variants and have never been described in cases of AMH or AMHR2 mutations. The role of chance is therefore extremely unlikely. LIMITATIONS, REASONS FOR CAUTION The main limitation of the study is the lack of experimental validation of the role of PPP1R12A in Müllerian regression. Only circumstantial evidence is available, myosin phosphatase is required for cell mobility, which plays a major role in Müllerian regression. Alternatively, PPP1R12A mutations could affect the AMH transduction pathway. WIDER IMPLICATIONS OF THE FINDINGS The study supports the conclusion that failure of Müllerian regression in males is not necessarily associated with a defect in AMH signaling. Extending the scope of molecular analysis should shed light upon the mechanism of the initial steps of male sex differentiation. STUDY FUNDING/COMPETING INTEREST(S) The study was funded by la Fondation Maladies Rares, GenOmics 2021_0404 and la Fondation pour la Recherche Médicale, grant EQU201903007868. The authors report no conflict of interest. TRIAL REGISTRATION NUMBER N/A.
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Affiliation(s)
- Jean-Yves Picard
- Sorbonne Université, INSERM, Centre de Recherches Saint-Antoine, Lipodystrophies, Adaptations Métaboliques et Hormonales et Vieillissement, UMR_S 938, Paris, France
| | - Gilles Morin
- Department of Medical Genetics, Centre Hospitalo-Universitaire d'Amiens, Amiens, France
| | | | | | - Serge Klosowski
- Service de Néonatologie, Centre Universitaire de Lens, Lens, France
| | | | | | - Cécile Masson
- Bioinformatics Core Facility, Institut Imagine-Structure Fédérative de Recherche Necker, INSERM U1163 et INSERM US24/CNRS UAR3633, Paris Descartes University, Sorbonne Paris Cite University, Paris, France
| | - Christine Bole
- Genomics Core Facility, Institut Imagine, Structure Fédérative de Recherche Necker, INSERM 1163, INSERM US24/CNRS UAR3633, Paris Descartes University, Sorbonne Paris Cité University, Paris, France
| | - Nathalie Josso
- Sorbonne Université, INSERM, Centre de Recherches Saint-Antoine, Lipodystrophies, Adaptations Métaboliques et Hormonales et Vieillissement, UMR_S 938, Paris, France
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PEAR1 regulates expansion of activated fibroblasts and deposition of extracellular matrix in pulmonary fibrosis. Nat Commun 2022; 13:7114. [PMID: 36402779 PMCID: PMC9675736 DOI: 10.1038/s41467-022-34870-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 11/09/2022] [Indexed: 11/21/2022] Open
Abstract
Pulmonary fibrosis is a chronic interstitial lung disease that causes irreversible and progressive lung scarring and respiratory failure. Activation of fibroblasts plays a central role in the progression of pulmonary fibrosis. Here we show that platelet endothelial aggregation receptor 1 (PEAR1) in fibroblasts may serve as a target for pulmonary fibrosis therapy. Pear1 deficiency in aged mice spontaneously causes alveolar collagens accumulation. Mesenchyme-specific Pear1 deficiency aggravates bleomycin-induced pulmonary fibrosis, confirming that PEAR1 potentially modulates pulmonary fibrosis progression via regulation of mesenchymal cell function. Moreover, single cell and bulk tissue RNA-seq analysis of pulmonary fibroblast reveals the expansion of Activated-fibroblast cluster and enrichment of marker genes in extracellular matrix development in Pear1-/- fibrotic lungs. We further show that PEAR1 associates with Protein Phosphatase 1 to suppress fibrotic factors-induced intracellular signalling and fibroblast activation. Intratracheal aerosolization of monoclonal antibodies activating PEAR1 greatly ameliorates pulmonary fibrosis in both WT and Pear1-humanized mice, significantly improving their survival rate.
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Molecular architecture of the glycogen- committed PP1/PTG holoenzyme. Nat Commun 2022; 13:6199. [PMID: 36261419 PMCID: PMC9582199 DOI: 10.1038/s41467-022-33693-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 09/27/2022] [Indexed: 12/24/2022] Open
Abstract
The delicate alternation between glycogen synthesis and degradation is governed by the interplay between key regulatory enzymes altering the activity of glycogen synthase and phosphorylase. Among these, the PP1 phosphatase promotes glycogenesis while inhibiting glycogenolysis. PP1 is, however, a master regulator of a variety of cellular processes, being conveniently directed to each of them by scaffolding subunits. PTG, Protein Targeting to Glycogen, addresses PP1 action to glycogen granules. In Lafora disease, the most aggressive pediatric epilepsy, genetic alterations leading to PTG accumulation cause the deposition of insoluble polyglucosans in neurons. Here, we report the crystallographic structure of the ternary complex PP1/PTG/carbohydrate. We further refine the mechanism of the PTG-mediated PP1 recruitment to glycogen by identifying i) an unusual combination of recruitment sites, ii) their contributions to the overall binding affinity, and iii) the conformational heterogeneity of this complex by in solution SAXS analyses.
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Archambault V, Li J, Emond-Fraser V, Larouche M. Dephosphorylation in nuclear reassembly after mitosis. Front Cell Dev Biol 2022; 10:1012768. [PMID: 36268509 PMCID: PMC9576876 DOI: 10.3389/fcell.2022.1012768] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 08/31/2022] [Indexed: 11/13/2022] Open
Abstract
In most animal cell types, the interphase nucleus is largely disassembled during mitotic entry. The nuclear envelope breaks down and chromosomes are compacted into separated masses. Chromatin organization is also mostly lost and kinetochores assemble on centromeres. Mitotic protein kinases play several roles in inducing these transformations by phosphorylating multiple effector proteins. In many of these events, the mechanistic consequences of phosphorylation have been characterized. In comparison, how the nucleus reassembles at the end of mitosis is less well understood in mechanistic terms. In recent years, much progress has been made in deciphering how dephosphorylation of several effector proteins promotes nuclear envelope reassembly, chromosome decondensation, kinetochore disassembly and interphase chromatin organization. The precise roles of protein phosphatases in this process, in particular of the PP1 and PP2A groups, are emerging. Moreover, how these enzymes are temporally and spatially regulated to ensure that nuclear reassembly progresses in a coordinated manner has been partly uncovered. This review provides a global view of nuclear reassembly with a focus on the roles of dephosphorylation events. It also identifies important open questions and proposes hypotheses.
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Affiliation(s)
- Vincent Archambault
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
- Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, QC, Canada
- *Correspondence: Vincent Archambault,
| | - Jingjing Li
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
- Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, QC, Canada
| | - Virginie Emond-Fraser
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
- Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, QC, Canada
| | - Myreille Larouche
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
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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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