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Hassanein F, Fadel HH, Shehata AI, Hamdy NA, Masoud IM. In silico study to explore the mechanism of Toxoplasma-induced inflammation and target therapy based on sero and salivary Toxoplasma. Sci Rep 2024; 14:13600. [PMID: 38866852 PMCID: PMC11169245 DOI: 10.1038/s41598-024-63735-z] [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: 04/17/2024] [Accepted: 05/31/2024] [Indexed: 06/14/2024] Open
Abstract
We aimed to assess salivary and seroprevalence of Toxoplasma immunoglobulins in risky populations and evaluate drug docking targeting TgERP. A cross-sectional study was conducted in Alexandria University hospitals' outpatient clinics. 192 participants were enrolled from September 2022 to November 2023. Anti-Toxoplasma IgG and IgM were determined in serum and saliva by ELISA. An in-Silico study examined TgERP's protein-protein interactions (PPIs) with pro-inflammatory cytokine receptors, anti-inflammatory cytokine, cell cycle progression regulatory proteins, a proliferation marker, and nuclear envelope integrity-related protein Lamin B1. Our findings revealed that anti-T. gondii IgG were detected in serum (66.1%) and saliva (54.7%), with 2.1% of both samples were positive for IgM. Salivary IgG had 75.59% sensitivity, 86.15% specificity, 91.40% PPV, 64.40% NPP, 79.17% accuracy and fair agreement with serum IgG. On the other hand, the sensitivity, specificity, PPV, NPV, and accuracy in detecting salivary IgM were 75.0%, 99.47%, 75.0%, 99.47%, and 98.96%. AUC 0.859 indicates good discriminatory power. Examined synthetic drugs and natural products can target specific amino acids residues of TgERP that lie at the same binding interface with LB1 and Ki67, subsequently, hindering their interaction. Hence, salivary samples can be a promising diagnostic approach. The studied drugs can counteract the pro-inflammatory action of TgERP.
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Affiliation(s)
- Faika Hassanein
- Department of Microbiology & Immunology, Faculty of Dentistry, Pharos University in Alexandria, Alexandria, Egypt.
| | - Hewida H Fadel
- Department of Medical Laboratory Technology, Faculty of Applied Health Sciences Technology, Pharos University in Alexandria, Alexandria, Egypt
| | - Amany I Shehata
- Department of Tropical Health, High Institute of Public Health, Alexandria University, Alexandria, Egypt
| | - Noha Alaa Hamdy
- Department of Clinical Pharmacy & Pharmacy Practice, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Inas M Masoud
- Department of Pharmacology and Therapeutics, Faculty of Pharmacy, Pharos University in Alexandria, Alexandria, Egypt
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2
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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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3
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Pan B, Gardner SM, Schultz K, Perez RM, Deng S, Shimogawa M, Sato K, Rhoades E, Marmorstein R, Petersson EJ. Semi-Synthetic CoA-α-Synuclein Constructs Trap N-Terminal Acetyltransferase NatB for Binding Mechanism Studies. J Am Chem Soc 2023; 145:14019-14030. [PMID: 37319422 PMCID: PMC10728591 DOI: 10.1021/jacs.3c03887] [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] [Indexed: 06/17/2023]
Abstract
N-terminal acetylation is a chemical modification carried out by N-terminal acetyltransferases. A major member of this enzyme family, NatB, acts on much of the human proteome, including α-synuclein (αS), a synaptic protein that mediates vesicle trafficking. NatB acetylation of αS modulates its lipid vesicle binding properties and amyloid fibril formation, which underlies its role in the pathogenesis of Parkinson's disease. Although the molecular details of the interaction between human NatB (hNatB) and the N-terminus of αS have been resolved, whether the remainder of the protein plays a role in interacting with the enzyme is unknown. Here, we execute the first synthesis, by native chemical ligation, of a bisubstrate inhibitor of NatB consisting of coenzyme A and full-length human αS, additionally incorporating two fluorescent probes for studies of conformational dynamics. We use cryo-electron microscopy (cryo-EM) to characterize the structural features of the hNatB/inhibitor complex and show that, beyond the first few residues, αS remains disordered when in complex with hNatB. We further probe changes in the αS conformation by single molecule Förster resonance energy transfer (smFRET) to reveal that the C-terminus expands when bound to hNatB. Computational models based on the cryo-EM and smFRET data help to explain the conformational changes as well as their implications for hNatB substrate recognition and specific inhibition of the interaction with αS. Beyond the study of αS and NatB, these experiments illustrate valuable strategies for the study of challenging structural biology targets through a combination of protein semi-synthesis, cryo-EM, smFRET, and computational modeling.
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Affiliation(s)
- Buyan Pan
- Department of Chemistry; University of Pennsylvania; 231 South 34th Street; Philadelphia, PA 19104, USA
| | - Sarah M. Gardner
- Graduate Group in Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, 421 Curie Boulevard, Philadelphia, PA 19104, USA
- Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kollin Schultz
- Graduate Group in Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, 421 Curie Boulevard, Philadelphia, PA 19104, USA
- Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ryann M. Perez
- Department of Chemistry; University of Pennsylvania; 231 South 34th Street; Philadelphia, PA 19104, USA
| | - Sunbin Deng
- Department of Chemistry; University of Pennsylvania; 231 South 34th Street; Philadelphia, PA 19104, USA
- Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Marie Shimogawa
- Department of Chemistry; University of Pennsylvania; 231 South 34th Street; Philadelphia, PA 19104, USA
| | - Kohei Sato
- Department of Chemistry; University of Pennsylvania; 231 South 34th Street; Philadelphia, PA 19104, USA
- Department of Engineering, Graduate School of Integrated Science and Technology, Shizuoka University, 3-5-1 Johoku, Hamamatsu, Shizuoka 432-8561, Japan
| | - Elizabeth Rhoades
- Department of Chemistry; University of Pennsylvania; 231 South 34th Street; Philadelphia, PA 19104, USA
- Graduate Group in Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, 421 Curie Boulevard, Philadelphia, PA 19104, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, 421 Curie Boulevard, Philadelphia, PA 19104, USA
| | - Ronen Marmorstein
- Department of Chemistry; University of Pennsylvania; 231 South 34th Street; Philadelphia, PA 19104, USA
- Graduate Group in Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, 421 Curie Boulevard, Philadelphia, PA 19104, USA
- Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, 421 Curie Boulevard, Philadelphia, PA 19104, USA
| | - E. James Petersson
- Department of Chemistry; University of Pennsylvania; 231 South 34th Street; Philadelphia, PA 19104, USA
- Graduate Group in Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, 421 Curie Boulevard, Philadelphia, PA 19104, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, 421 Curie Boulevard, Philadelphia, PA 19104, USA
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4
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Pan B, Gardner S, Schultz K, Perez RM, Deng S, Shimogawa M, Sato K, Rhoades E, Marmorstein R, Petersson EJ. Semi-synthetic CoA-α-Synuclein Constructs Trap N-terminal Acetyltransferase NatB for Binding Mechanism Studies. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.03.535351. [PMID: 37066334 PMCID: PMC10104007 DOI: 10.1101/2023.04.03.535351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/18/2023]
Abstract
N-terminal acetylation is a chemical modification carried out by N-terminal acetyltransferases (NATs). A major member of this enzyme family, NatB, acts on much of the human proteome, including α-synuclein (αS), a synaptic protein that mediates vesicle trafficking. NatB acetylation of αS modulates its lipid vesicle binding properties and amyloid fibril formation, which underlies its role in the pathogenesis of Parkinson's disease. Although the molecular details of the interaction between human NatB (hNatB) and the N-terminus of αS have been resolved, whether the remainder of the protein plays a role in interacting with the enzyme is unknown. Here we execute the first synthesis, by native chemical ligation, of a bisubstrate inhibitor of NatB consisting of coenzyme A and full-length human αS, additionally incorporating two fluorescent probes for studies of conformational dynamics. We use cryo-electron microscopy (cryo-EM) to characterize the structural features of the hNatB/inhibitor complex and show that, beyond the first few residues, αS remains disordered when in complex with hNatB. We further probe changes in the αS conformation by single molecule Förster resonance energy transfer (smFRET) to reveal that the C-terminus expands when bound to hNatB. Computational models based on the cryo-EM and smFRET data help to explain the conformational changes and their implications for hNatB substrate recognition and specific inhibition of the interaction with αS. Beyond the study of αS and NatB, these experiments illustrate valuable strategies for the study of challenging structural biology targets through a combination of protein semi-synthesis, cryo-EM, smFRET, and computational modeling.
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5
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Ferreira AF, Santiago J, Silva JV, Oliveira PF, Fardilha M. PP1, PP2A and PP2B Interplay in the Regulation of Sperm Motility: Lessons from Protein Phosphatase Inhibitors. Int J Mol Sci 2022; 23:ijms232315235. [PMID: 36499559 PMCID: PMC9737803 DOI: 10.3390/ijms232315235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 11/30/2022] [Accepted: 12/01/2022] [Indexed: 12/11/2022] Open
Abstract
Male fertility relies on the ability of spermatozoa to fertilize the egg in the female reproductive tract (FRT). Spermatozoa acquire activated motility during epididymal maturation; however, to be capable of fertilization, they must achieve hyperactivated motility in the FRT. Extensive research found that three protein phosphatases (PPs) are crucial to sperm motility regulation, the sperm-specific protein phosphatase type 1 (PP1) isoform gamma 2 (PP1γ2), protein phosphatase type 2A (PP2A) and protein phosphatase type 2B (PP2B). Studies have reported that PP activity decreases during epididymal maturation, whereas protein kinase activity increases, which appears to be a requirement for motility acquisition. An interplay between these PPs has been extensively investigated; however, many specific interactions and some inconsistencies remain to be elucidated. The study of PPs significantly advanced following the identification of naturally occurring toxins, including calyculin A, okadaic acid, cyclosporin, endothall and deltamethrin, which are powerful and specific PP inhibitors. This review aims to overview the protein phosphorylation-dependent biochemical pathways underlying sperm motility acquisition and hyperactivation, followed by a discussion of the PP inhibitors that allowed advances in the current knowledge of these pathways. Since male infertility cases still attain alarming numbers, additional research on the topic is required, particularly using other PP inhibitors.
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Affiliation(s)
- Ana F. Ferreira
- Laboratory of Signal Transduction, Institute for Biomedicine-iBiMED, Medical Sciences Department, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Joana Santiago
- Laboratory of Signal Transduction, Institute for Biomedicine-iBiMED, Medical Sciences Department, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Joana V. Silva
- Laboratory of Signal Transduction, Institute for Biomedicine-iBiMED, Medical Sciences Department, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Pedro F. Oliveira
- QOPNA & LAQV, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Margarida Fardilha
- Laboratory of Signal Transduction, Institute for Biomedicine-iBiMED, Medical Sciences Department, University of Aveiro, 3810-193 Aveiro, Portugal
- Correspondence: ; Tel.: +351-918-143-947
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6
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Bonsor DA, Alexander P, Snead K, Hartig N, Drew M, Messing S, Finci LI, Nissley DV, McCormick F, Esposito D, Rodriguez-Viciana P, Stephen AG, Simanshu DK. Structure of the SHOC2-MRAS-PP1C complex provides insights into RAF activation and Noonan syndrome. Nat Struct Mol Biol 2022; 29:966-977. [PMID: 36175670 PMCID: PMC10365013 DOI: 10.1038/s41594-022-00841-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 08/12/2022] [Indexed: 11/08/2022]
Abstract
SHOC2 acts as a strong synthetic lethal interactor with MEK inhibitors in multiple KRAS cancer cell lines. SHOC2 forms a heterotrimeric complex with MRAS and PP1C that is essential for regulating RAF and MAPK-pathway activation by dephosphorylating a specific phosphoserine on RAF kinases. Here we present the high-resolution crystal structure of the SHOC2-MRAS-PP1C (SMP) complex and apo-SHOC2. Our structures reveal that SHOC2, MRAS, and PP1C form a stable ternary complex in which all three proteins synergistically interact with each other. Our results show that dephosphorylation of RAF substrates by PP1C is enhanced upon interacting with SHOC2 and MRAS. The SMP complex forms only when MRAS is in an active state and is dependent on SHOC2 functioning as a scaffolding protein in the complex by bringing PP1C and MRAS together. Our results provide structural insights into the role of the SMP complex in RAF activation and how mutations found in Noonan syndrome enhance complex formation, and reveal new avenues for therapeutic interventions.
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Affiliation(s)
- Daniel A Bonsor
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Patrick Alexander
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Kelly Snead
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Nicole Hartig
- UCL Cancer Institute, University College London, London, UK
| | - Matthew Drew
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Simon Messing
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Lorenzo I Finci
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Dwight V Nissley
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Frank McCormick
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
- University of California, San Francisco Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA
| | - Dominic Esposito
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | | | - Andrew G Stephen
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Dhirendra K Simanshu
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA.
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7
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Hauseman ZJ, Fodor M, Dhembi A, Viscomi J, Egli D, Bleu M, Katz S, Park E, Jang DM, Porter KA, Meili F, Guo H, Kerr G, Mollé S, Velez-Vega C, Beyer KS, Galli GG, Maira SM, Stams T, Clark K, Eck MJ, Tordella L, Thoma CR, King DA. Structure of the MRAS-SHOC2-PP1C phosphatase complex. Nature 2022; 609:416-423. [PMID: 35830882 PMCID: PMC9452295 DOI: 10.1038/s41586-022-05086-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 07/07/2022] [Indexed: 11/09/2022]
Abstract
RAS-MAPK signalling is fundamental for cell proliferation and is altered in most human cancers1-3. However, our mechanistic understanding of how RAS signals through RAF is still incomplete. Although studies revealed snapshots for autoinhibited and active RAF-MEK1-14-3-3 complexes4, the intermediate steps that lead to RAF activation remain unclear. The MRAS-SHOC2-PP1C holophosphatase dephosphorylates RAF at serine 259, resulting in the partial displacement of 14-3-3 and RAF-RAS association3,5,6. MRAS, SHOC2 and PP1C are mutated in rasopathies-developmental syndromes caused by aberrant MAPK pathway activation6-14-and SHOC2 itself has emerged as potential target in receptor tyrosine kinase (RTK)-RAS-driven tumours15-18. Despite its importance, structural understanding of the SHOC2 holophosphatase is lacking. Here we determine, using X-ray crystallography, the structure of the MRAS-SHOC2-PP1C complex. SHOC2 bridges PP1C and MRAS through its concave surface and enables reciprocal interactions between all three subunits. Biophysical characterization indicates a cooperative assembly driven by the MRAS GTP-bound active state, an observation that is extendible to other RAS isoforms. Our findings support the concept of a RAS-driven and multi-molecular model for RAF activation in which individual RAS-GTP molecules recruit RAF-14-3-3 and SHOC2-PP1C to produce downstream pathway activation. Importantly, we find that rasopathy and cancer mutations reside at protein-protein interfaces within the holophosphatase, resulting in enhanced affinities and function. Collectively, our findings shed light on a fundamental mechanism of RAS biology and on mechanisms of clinically observed enhanced RAS-MAPK signalling, therefore providing the structural basis for therapeutic interventions.
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Affiliation(s)
| | - Michelle Fodor
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Anxhela Dhembi
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Jessica Viscomi
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - David Egli
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Melusine Bleu
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Stephanie Katz
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Eunyoung Park
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Dong Man Jang
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | | | - Fabian Meili
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Hongqiu Guo
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Grainne Kerr
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Sandra Mollé
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | | | - Kim S Beyer
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Giorgio G Galli
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | | | - Travis Stams
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Kirk Clark
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Michael J Eck
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Luca Tordella
- Novartis Institutes for BioMedical Research, Basel, Switzerland.
| | - Claudio R Thoma
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA.
| | - Daniel A King
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA.
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Regulation of Synaptic Transmission and Plasticity by Protein Phosphatase 1. J Neurosci 2021; 41:3040-3050. [PMID: 33827970 DOI: 10.1523/jneurosci.2026-20.2021] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 01/22/2023] Open
Abstract
Protein phosphatases, by counteracting protein kinases, regulate the reversible phosphorylation of many substrates involved in synaptic plasticity, a cellular model for learning and memory. A prominent phosphatase regulating synaptic plasticity and neurologic disorders is the serine/threonine protein phosphatase 1 (PP1). PP1 has three isoforms (α, β, and γ, encoded by three different genes), which are regulated by a vast number of interacting subunits that define their enzymatic substrate specificity. In this review, we discuss evidence showing that PP1 regulates synaptic transmission and plasticity, as well as presenting novel models of PP1 regulation suggested by recent experimental evidence. We also outline the required targeting of PP1 by neurabin and spinophilin to achieve substrate specificity at the synapse to regulate AMPAR and NMDAR function. We then highlight the role of inhibitor-2 in regulating PP1 function in plasticity, including its positive regulation of PP1 function in vivo in memory formation. We also discuss the distinct function of the three PP1 isoforms in synaptic plasticity and brain function, as well as briefly discuss the role of inhibitory phosphorylation of PP1, which has received recent emphasis in the regulation of PP1 activity in neurons.
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9
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Vagnarelli P. Back to the new beginning: Mitotic exit in space and time. Semin Cell Dev Biol 2021; 117:140-148. [PMID: 33810980 DOI: 10.1016/j.semcdb.2021.03.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 03/16/2021] [Accepted: 03/16/2021] [Indexed: 11/16/2022]
Abstract
The ultimate goal of cell division is to generate two identical daughter cells that resemble the mother cell from which they derived. Once all the proper attachments to the spindle have occurred, the chromosomes have aligned at the metaphase plate and the spindle assembly checkpoint (a surveillance mechanism that halts cells form progressing in the cell cycle in case of spindle - microtubule attachment errors) has been satisfied, mitotic exit will occur. Mitotic exit has the purpose of completing the separation of the genomic material but also to rebuild the cellular structures necessary for the new cell cycle. This stage of mitosis received little attention until a decade ago, therefore our knowledge is much patchier than the molecular details we now have for the early stages of mitosis. However, it is emerging that mitotic exit is not just the simple reverse of mitotic entry and it is highly regulated in space and time. In this review I will discuss the main advances in the field that provided us with a better understanding on the key role of protein phosphorylation/de-phosphorylation in this transition together with the concept of their spatial regulation. As this field is much younger, I will highlight general consensus, contrasting views together with the outstanding questions awaiting for answers.
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Affiliation(s)
- Paola Vagnarelli
- College of Medicine, Health and Life Science, Centre for Genomic Engineering and Maintenance (CenGEM), Brunel University London, Uxbridge UB8 3PH, UK.
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10
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Li X, Ye Y, Wang B, Zhao S. miR-140-5p Aggravates Insulin Resistance via Directly Targeting GYS1 and PPP1CC in Insulin-Resistant HepG2 Cells. Diabetes Metab Syndr Obes 2021; 14:2515-2524. [PMID: 34113143 PMCID: PMC8187005 DOI: 10.2147/dmso.s304055] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 05/20/2021] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Much attention has been paid to the regulatory role of microRNA (miRNA) in insulin resistance. Nevertheless, how miR-140-5p regulates insulin resistance remains unclear. In this research, we aim to investigate the roles of miR-140-5p in insulin resistance. METHODS qRT-PCR is used to analyze the expression level of miR-140-5p in insulin-resistant HepG2 cells. Glucose consumption and glucose uptake are detected to study the effect of miR-140-5p knockdown in insulin-resistant HepG2 cells and miR-140-5p overexpression in HepG2 cells. Bioinformatic analysis, luciferase reporter assay and confirmatory experiments are applied to identify the target gene bound with miR-140-5p and study the effect of miR-140-5p on the downstream substrates of target genes. Rescue experiments have verified the roles of miR-140-5p and target gene in glucose metabolism. RESULTS The expression level of miR-140-5p was upregulated in insulin-resistant HepG2 cells and was significantly correlated with cellular glucose metabolism. Functionally, miR-140-5p overexpression induced impairment of glucose consumption and glucose uptake. Besides, bioinformatics analysis indicated that glycogen synthetase (GYS1) and protein phosphatase 1 catalytic subunit gamma (PPP1CC) were the target genes of miR-140-5p. Western blotting and qRT-PCR results revealed a negative correlation between GYS1, PPP1CC and miR-140-5p. The glycogen detection results showed that miR140-5p inhibited the production of the downstream substrates of the target gene. Rescue experiments showed that inhibition of GYS1 or PPP1CC partially enhanced the insulin-resistant effects of miR-140-5p knockdown in insulin-resistant HepG2 cells. CONCLUSION miR-140-5p overexpression augments the development of insulin resistance and miR-140-5p may be served as a therapeutic target of metabolic diseases.
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Affiliation(s)
- Xuemei Li
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, 300134, People’s Republic of China
- Correspondence: Xuemei Li; Shujun Zhao NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, 300134, People’s Republic of China Email ;
| | - Yan Ye
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, 300134, People’s Republic of China
| | - Baoli Wang
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, 300134, People’s Republic of China
| | - Shujun Zhao
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, 300134, People’s Republic of China
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11
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Salvi F, Hoermann B, Del Pino García J, Fontanillo M, Derua R, Beullens M, Bollen M, Barabas O, Köhn M. Towards Dissecting the Mechanism of Protein Phosphatase-1 Inhibition by Its C-Terminal Phosphorylation. Chembiochem 2020; 22:834-838. [PMID: 33085143 PMCID: PMC7984433 DOI: 10.1002/cbic.202000669] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 10/21/2020] [Indexed: 01/23/2023]
Abstract
Phosphoprotein phosphatase‐1 (PP1) is a key player in the regulation of phospho‐serine (pSer) and phospho‐threonine (pThr) dephosphorylation and is involved in a large fraction of cellular signaling pathways. Aberrant activity of PP1 has been linked to many diseases, including cancer and heart failure. Besides a well‐established activity control by regulatory proteins, an inhibitory function for phosphorylation (p) of a Thr residue in the C‐terminal intrinsically disordered tail of PP1 has been demonstrated. The associated phenotype of cell‐cycle arrest was repeatedly proposed to be due to autoinhibition of PP1 through either conformational changes or substrate competition. Here, we use PP1 variants created by mutations and protein semisynthesis to differentiate between these hypotheses. Our data support the hypothesis that pThr exerts its inhibitory function by mediating protein complex formation rather than by a direct mechanism of structural changes or substrate competition.
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Affiliation(s)
- Francesca Salvi
- Genome Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117, Heidelberg, Germany
| | - Bernhard Hoermann
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Schänzlestraße 18, 79104, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Schänzlestraße 18, 79104, Freiburg, Germany
| | - Javier Del Pino García
- Laboratory of Biosignaling and Therapeutics Department of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Miriam Fontanillo
- Genome Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117, Heidelberg, Germany
| | - Rita Derua
- Laboratory of Protein Phosphorylation and Proteomics Department of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, 3000, Leuven, Belgium.,SyBioMa, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Monique Beullens
- Laboratory of Biosignaling and Therapeutics Department of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Mathieu Bollen
- Laboratory of Biosignaling and Therapeutics Department of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Orsolya Barabas
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117, Heidelberg, Germany
| | - Maja Köhn
- Genome Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117, Heidelberg, Germany.,Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Schänzlestraße 18, 79104, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Schänzlestraße 18, 79104, Freiburg, Germany
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