1
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Falzone ME, MacKinnon R. The mechanism of Gαq regulation of PLCβ3-catalyzed PIP2 hydrolysis. Proc Natl Acad Sci U S A 2023; 120:e2315011120. [PMID: 37991948 PMCID: PMC10691244 DOI: 10.1073/pnas.2315011120] [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: 08/30/2023] [Accepted: 10/13/2023] [Indexed: 11/24/2023] Open
Abstract
PLCβ (Phospholipase Cβ) enzymes cleave phosphatidylinositol 4,5-bisphosphate (PIP2) producing IP3 and DAG (diacylglycerol). PIP2 modulates the function of many ion channels, while IP3 and DAG regulate intracellular Ca2+ levels and protein phosphorylation by protein kinase C, respectively. PLCβ enzymes are under the control of G protein coupled receptor signaling through direct interactions with G proteins Gβγ and Gαq and have been shown to be coincidence detectors for dual stimulation of Gαq and Gαi-coupled receptors. PLCβs are aqueous-soluble cytoplasmic enzymes but partition onto the membrane surface to access their lipid substrate, complicating their functional and structural characterization. Using newly developed methods, we recently showed that Gβγ activates PLCβ3 by recruiting it to the membrane. Using these same methods, here we show that Gαq increases the catalytic rate constant, kcat, of PLCβ3. Since stimulation of PLCβ3 by Gαq depends on an autoinhibitory element (the X-Y linker), we propose that Gαq produces partial relief of the X-Y linker autoinhibition through an allosteric mechanism. We also determined membrane-bound structures of the PLCβ3·Gαq and PLCβ3·Gβγ(2)·Gαq complexes, which show that these G proteins can bind simultaneously and independently of each other to regulate PLCβ3 activity. The structures rationalize a finding in the enzyme assay, that costimulation by both G proteins follows a product rule of each independent stimulus. We conclude that baseline activity of PLCβ3 is strongly suppressed, but the effect of G proteins, especially acting together, provides a robust stimulus upon G protein stimulation.
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Affiliation(s)
- Maria E. Falzone
- Laboratory of Molecular Neurobiology and Biophysics, The Rockefeller University, New York, NY10065
- HHMI, The Rockefeller University, New York, NY10065
| | - Roderick MacKinnon
- Laboratory of Molecular Neurobiology and Biophysics, The Rockefeller University, New York, NY10065
- HHMI, The Rockefeller University, New York, NY10065
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2
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Falzone ME, MacKinnon R. The mechanism of Gα q regulation of PLCβ3 -catalyzed PIP2 hydrolysis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.29.555394. [PMID: 37693483 PMCID: PMC10491199 DOI: 10.1101/2023.08.29.555394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
PLCβ enzymes cleave PIP2 producing IP3 and DAG. PIP2 modulates the function of many ion channels, while IP3 and DAG regulate intracellular Ca 2+ levels and protein phosphorylation by protein kinase C, respectively. PLCβ enzymes are under the control of GPCR signaling through direct interactions with G proteins Gβγ and Gα q and have been shown to be coincidence detectors for dual stimulation of Gα q and G α i coupled receptors. PLCβs are aqueous-soluble cytoplasmic enzymes, but partition onto the membrane surface to access their lipid substrate, complicating their functional and structural characterization. Using newly developed methods, we recently showed that Gβγ activates PLCβ3 by recruiting it to the membrane. Using these same methods, here we show that Gα q increases the catalytic rate constant, k cat , of PLCβ3 . Since stimulation of PLCβ3 by Gα q depends on an autoinhibitory element (the X-Y linker), we propose that Gα q produces partial relief of the X-Y linker autoinhibition through an allosteric mechanism. We also determined membrane-bound structures of the PLCβ3-Gα q , and PLCβ3-Gβγ(2)-Gα q complexes, which show that these G proteins can bind simultaneously and independently of each other to regulate PLCβ3 activity. The structures rationalize a finding in the enzyme assay, that co-stimulation by both G proteins follows a product rule of each independent stimulus. We conclude that baseline activity of PLCβ3 is strongly suppressed, but the effect of G proteins, especially acting together, provides a robust stimulus upon G protein stimulation. Significance Statement For certain cellular signaling processes, the background activity of signaling enzymes must be minimal and stimulus-dependent activation robust. Nowhere is this truer than in signaling by PLCβ3 , whose activity regulates intracellular Ca 2+ , phosphorylation by Protein Kinase C, and the activity of numerous ion channels and membrane receptors. In this study we show how PLCβ3 enzymes are regulated by two kinds of G proteins, Gβγ and Gα q . Enzyme activity studies and structures on membranes show how these G proteins act by separate, independent mechanisms, leading to a product rule of co-stimulation when they act together. The findings explain how cells achieve robust stimulation of PLCβ3 in the setting of very low background activity, properties essential to cell health and survival.
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3
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Kanemaru K, Nakamura Y. Activation Mechanisms and Diverse Functions of Mammalian Phospholipase C. Biomolecules 2023; 13:915. [PMID: 37371495 DOI: 10.3390/biom13060915] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 05/28/2023] [Accepted: 05/29/2023] [Indexed: 06/29/2023] Open
Abstract
Phospholipase C (PLC) plays pivotal roles in regulating various cellular functions by metabolizing phosphatidylinositol 4,5-bisphosphate in the plasma membrane. This process generates two second messengers, inositol 1,4,5-trisphosphate and diacylglycerol, which respectively regulate the intracellular Ca2+ levels and protein kinase C activation. In mammals, six classes of typical PLC have been identified and classified based on their structure and activation mechanisms. They all share X and Y domains, which are responsible for enzymatic activity, as well as subtype-specific domains. Furthermore, in addition to typical PLC, atypical PLC with unique structures solely harboring an X domain has been recently discovered. Collectively, seven classes and 16 isozymes of mammalian PLC are known to date. Dysregulation of PLC activity has been implicated in several pathophysiological conditions, including cancer, cardiovascular diseases, and neurological disorders. Therefore, identification of new drug targets that can selectively modulate PLC activity is important. The present review focuses on the structures, activation mechanisms, and physiological functions of mammalian PLC.
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Affiliation(s)
- Kaori Kanemaru
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, Chiba 278-8510, Japan
| | - Yoshikazu Nakamura
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, Chiba 278-8510, Japan
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4
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Visvanathan R, Utsuki T, Beck DE, Lendy E, Sun KL, Liu Y, Hering KW, Mesecar A, Zhang ZY, Putt KS. A novel fluorogenic reporter substrate for 1-phosphatidylinositol 4,5-bisphosphate phosphodiesterase gamma-2 (PLCγ2): Application to high-throughput screening for activators to treat Alzheimer's disease. SLAS DISCOVERY : ADVANCING LIFE SCIENCES R & D 2023:S2472-5552(23)00024-2. [PMID: 36933698 DOI: 10.1016/j.slasd.2023.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 02/17/2023] [Accepted: 03/13/2023] [Indexed: 03/18/2023]
Abstract
A rare coding variant in PLCγ2 (P522R) expressed in microglia induces a mild activation of enzymatic activity when compared to wild-type. This mutation is reported to be protective against the cognitive decline associated with late-onset Alzheimer's disease (LOAD) and therefore, activation of wild-type PLCγ2 has been suggested as a potential therapeutic target for the prevention and treatment of LOAD. Additionally, PLCγ2 has been associated with other diseases such as cancer and some autoimmune disorders where mutations with much greater increases in PLCγ2 activity have been identified. Here, pharmacological inhibition may provide a therapeutic effect. In order to facilitate our investigation of the activity of PLCγ2, we developed an optimized fluorogenic substrate to monitor enzymatic activity in aqueous solution. This was accomplished by first exploring the spectral properties of various "turn-on" fluorophores. The most promising turn-on fluorophore was incorporated into a water-soluble PLCγ2 reporter substrate, which we named C8CF3-coumarin. The ability of PLCγ2 to enzymatically process C8CF3-coumarin was confirmed, and the kinetics of the reaction were determined. Reaction conditions were optimized to identify small molecule activators, and a pilot screen of the Library of Pharmacologically Active Compounds 1280 (LOPAC1280) was performed with the goal of identifying small molecule activators of PLCγ2. The optimized screening conditions allowed identification of potential PLCγ2 activators and inhibitors, thus demonstrating the feasibility of this approach for high-throughput screening.
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Affiliation(s)
- Ramya Visvanathan
- Institute for Drug Discovery, Purdue University, West Lafayette, IN 47907, USA; IUSM-Purdue TREAT-AD Center, West Lafayette IN 47907, USA; Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA
| | - Tadanobu Utsuki
- Institute for Drug Discovery, Purdue University, West Lafayette, IN 47907, USA; IUSM-Purdue TREAT-AD Center, West Lafayette IN 47907, USA
| | - Daniel E Beck
- Institute for Drug Discovery, Purdue University, West Lafayette, IN 47907, USA; IUSM-Purdue TREAT-AD Center, West Lafayette IN 47907, USA
| | - Emma Lendy
- IUSM-Purdue TREAT-AD Center, West Lafayette IN 47907, USA; Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Kuai-Lin Sun
- Cayman Chemical Company, 1180 East Ellsworth Road, Ann Arbor, MI 48108, USA
| | - Yinghui Liu
- Cayman Chemical Company, 1180 East Ellsworth Road, Ann Arbor, MI 48108, USA
| | - Kirk W Hering
- Cayman Chemical Company, 1180 East Ellsworth Road, Ann Arbor, MI 48108, USA
| | - Andrew Mesecar
- IUSM-Purdue TREAT-AD Center, West Lafayette IN 47907, USA; Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Zhong-Yin Zhang
- Institute for Drug Discovery, Purdue University, West Lafayette, IN 47907, USA; IUSM-Purdue TREAT-AD Center, West Lafayette IN 47907, USA; Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA
| | - Karson S Putt
- Institute for Drug Discovery, Purdue University, West Lafayette, IN 47907, USA; IUSM-Purdue TREAT-AD Center, West Lafayette IN 47907, USA.
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5
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Siraliev-Perez E, Stariha JTB, Hoffmann RM, Temple BRS, Zhang Q, Hajicek N, Jenkins ML, Burke JE, Sondek J. Dynamics of allosteric regulation of the phospholipase C-γ isozymes upon recruitment to membranes. eLife 2022; 11:77809. [PMID: 35708309 PMCID: PMC9203054 DOI: 10.7554/elife.77809] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 05/22/2022] [Indexed: 11/13/2022] Open
Abstract
Numerous receptor tyrosine kinases and immune receptors activate phospholipase C-γ (PLC-γ) isozymes at membranes to control diverse cellular processes including phagocytosis, migration, proliferation, and differentiation. The molecular details of this process are not well understood. Using hydrogen-deuterium exchange mass spectrometry, we show that PLC-γ1 is relatively inert to lipid vesicles that contain its substrate, phosphatidylinositol 4,5-bisphosphate (PIP2), unless first bound to the kinase domain of the fibroblast growth factor receptor (FGFR1). Exchange occurs throughout PLC-γ1 and is exaggerated in PLC-γ1 containing an oncogenic substitution (D1165H) that allosterically activates the lipase. These data support a model whereby initial complex formation shifts the conformational equilibrium of PLC-γ1 to favor activation. This receptor-induced priming of PLC-γ1 also explains the capacity of a kinase-inactive fragment of FGFR1 to modestly enhance the lipase activity of PLC-γ1 operating on lipid vesicles but not a soluble analog of PIP2 and highlights potential cooperativity between receptor engagement and membrane proximity. Priming is expected to be greatly enhanced for receptors embedded in membranes and nearly universal for the myriad of receptors and co-receptors that bind the PLC-γ isozymes.
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Affiliation(s)
- Edhriz Siraliev-Perez
- Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Jordan T B Stariha
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, Canada
| | - Reece M Hoffmann
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, Canada
| | - Brenda R S Temple
- Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Qisheng Zhang
- Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, United States.,Division of Chemical Biology and Medicinal Chemistry, School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, United States.,Lineberger Comprehensive Cancer Center, School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Nicole Hajicek
- Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Meredith L Jenkins
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, Canada
| | - John E Burke
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, Canada.,Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, Canada
| | - John Sondek
- Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, United States.,Lineberger Comprehensive Cancer Center, School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, United States.,Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, United States
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6
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Semproli R, Robescu MS, Cambò M, Mema K, Bavaro T, Rabuffetti M, Ubiali D, Speranza G. Chemical and Enzymatic Approaches to Esters of
sn
‐Glycero‐3‐Phosphoric Acid. European J Org Chem 2021. [DOI: 10.1002/ejoc.202100235] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Riccardo Semproli
- Department of Drug Sciences University of Pavia Viale Taramelli, 12 I-27100 Pavia Italy
| | - Marina S. Robescu
- Department of Drug Sciences University of Pavia Viale Taramelli, 12 I-27100 Pavia Italy
| | - Mattia Cambò
- Department of Chemistry University of Milano Via Golgi, 19 I-20133 Milano Italy
| | - Klodiana Mema
- Department of Drug Sciences University of Pavia Viale Taramelli, 12 I-27100 Pavia Italy
- Consorzio Italbiotec Piazza della Trivulziana 4/A 20126 Milano Italy
| | - Teodora Bavaro
- Department of Drug Sciences University of Pavia Viale Taramelli, 12 I-27100 Pavia Italy
| | - Marco Rabuffetti
- Department of Chemistry University of Milano Via Golgi, 19 I-20133 Milano Italy
| | - Daniela Ubiali
- Department of Drug Sciences University of Pavia Viale Taramelli, 12 I-27100 Pavia Italy
| | - Giovanna Speranza
- Department of Chemistry University of Milano Via Golgi, 19 I-20133 Milano Italy
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7
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Batrouni AG, Baskin JM. The chemistry and biology of phosphatidylinositol 4-phosphate at the plasma membrane. Bioorg Med Chem 2021; 40:116190. [PMID: 33965837 DOI: 10.1016/j.bmc.2021.116190] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/24/2021] [Accepted: 04/26/2021] [Indexed: 12/29/2022]
Abstract
Phosphoinositides are an important class of anionic, low abundance signaling lipids distributed throughout intracellular membranes. The plasma membrane contains three phosphoinositides: PI(4)P, PI(4,5)P2, and PI(3,4,5)P3. Of these, PI(4)P has remained the most mysterious, despite its characterization in this membrane more than a half-century ago. Fortunately, recent methodological innovations at the chemistry-biology interface have spurred a renaissance of interest in PI(4)P. Here, we describe these new toolsets and how they have revealed novel functions for the plasma membrane PI(4)P pool. We examine high-resolution structural characterization of the plasma membrane PI 4-kinase complex that produces PI(4)P, tools for modulating PI(4)P levels including isoform-selective PI 4-kinase inhibitors, and fluorescent probes for visualizing PI(4)P. Collectively, these chemical and biochemical approaches have revealed insights into how cells regulate synthesis of PI(4)P and its downstream metabolites as well as new roles for plasma membrane PI(4)P in non-vesicular lipid transport, membrane homeostasis and trafficking, and cell signaling pathways.
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Affiliation(s)
- Alex G Batrouni
- Department of Chemistry and Chemical Biology and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - Jeremy M Baskin
- Department of Chemistry and Chemical Biology and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA.
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8
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Fluorogenic XY-69 in Lipid Vesicles for Measuring Activity of Phospholipase C Isozymes. Methods Mol Biol 2021. [PMID: 33481244 DOI: 10.1007/978-1-0716-1142-5_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Mammalian phospholipase C (PLC) isozymes are major signaling nodes that regulate a wide range of cellular processes. Dysregulation of PLC activity has been associated with a growing list of human diseases such as cancer and Alzheimer's disease. However, methods to directly and continuously monitor PLC activity at membranes with high sensitivity and throughput are still lacking. We have developed XY-69, a fluorogenic PIP2 analog, which can be efficiently hydrolyzed by PLC isozymes either in solution or at membranes. Here, we describe the optimized assay conditions and protocol to measure the activity of PLC-γ1 (D1165H) with XY-69 in lipid vesicles. The described protocol also applies to other PLC isozymes.
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9
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Katan M, Cockcroft S. Phospholipase C families: Common themes and versatility in physiology and pathology. Prog Lipid Res 2020; 80:101065. [PMID: 32966869 DOI: 10.1016/j.plipres.2020.101065] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 08/14/2020] [Accepted: 09/17/2020] [Indexed: 12/20/2022]
Abstract
Phosphoinositide-specific phospholipase Cs (PLCs) are expressed in all mammalian cells and play critical roles in signal transduction. To obtain a comprehensive understanding of these enzymes in physiology and pathology, a detailed structural, biochemical, cell biological and genetic information is required. In this review, we cover all these aspects to summarize current knowledge of the entire superfamily. The families of PLCs have expanded from 13 enzymes to 16 with the identification of the atypical PLCs in the human genome. Recent structural insights highlight the common themes that cover not only the substrate catalysis but also the mechanisms of activation. This involves the release of autoinhibitory interactions that, in the absence of stimulation, maintain classical PLC enzymes in their inactive forms. Studies of individual PLCs provide a rich repertoire of PLC function in different physiologies. Furthermore, the genetic studies discovered numerous mutated and rare variants of PLC enzymes and their link to human disease development, greatly expanding our understanding of their roles in diverse pathologies. Notably, substantial evidence now supports involvement of different PLC isoforms in the development of specific cancer types, immune disorders and neurodegeneration. These advances will stimulate the generation of new drugs that target PLC enzymes, and will therefore open new possibilities for treatment of a number of diseases where current therapies remain ineffective.
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Affiliation(s)
- Matilda Katan
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London WC1E 6BT, UK
| | - Shamshad Cockcroft
- Department of Neuroscience, Physiology and Pharmacology, Division of Biosciences, University College London, 21 University Street, London WC1E 6JJ, UK.
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10
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Huang W, Carr AJ, Hajicek N, Sokolovski M, Siraliev-Perez E, Hardy PB, Pearce KH, Sondek J, Zhang Q. A High-Throughput Assay to Identify Allosteric Inhibitors of the PLC-γ Isozymes Operating at Membranes. Biochemistry 2020; 59:4029-4038. [PMID: 33028071 DOI: 10.1021/acs.biochem.0c00511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The two phospholipase C-γ (PLC-γ) isozymes are major signaling hubs and emerging therapeutic targets for various diseases, yet there are no selective inhibitors for these enzymes. We have developed a high-throughput, liposome-based assay that features XY-69, a fluorogenic, membrane-associated reporter for mammalian PLC isozymes. The assay was validated using a pilot screen of the Library of Pharmacologically Active Compounds 1280 (LOPAC1280) in 384-well format; it is highly reproducible and has the potential to capture both orthosteric and allosteric inhibitors. Selected hit compounds were confirmed with secondary assays, and further profiling led to the interesting discovery that adenosine triphosphate potently inhibits the PLC-γ isozymes through noncompetitive inhibition, raising the intriguing possibility of endogenous, nucleotide-dependent regulation of these phospholipases. These results highlight the merit of the assay platform for large scale screening of chemical libraries to identify allosteric modulators of the PLC-γ isozymes as chemical probes and for drug discovery.
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11
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Hajicek N, Keith NC, Siraliev-Perez E, Temple BRS, Huang W, Zhang Q, Harden TK, Sondek J. Structural basis for the activation of PLC-γ isozymes by phosphorylation and cancer-associated mutations. eLife 2019; 8:e51700. [PMID: 31889510 PMCID: PMC7004563 DOI: 10.7554/elife.51700] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 12/30/2019] [Indexed: 12/14/2022] Open
Abstract
Direct activation of the human phospholipase C-γ isozymes (PLC-γ1, -γ2) by tyrosine phosphorylation is fundamental to the control of diverse biological processes, including chemotaxis, platelet aggregation, and adaptive immunity. In turn, aberrant activation of PLC-γ1 and PLC-γ2 is implicated in inflammation, autoimmunity, and cancer. Although structures of isolated domains from PLC-γ isozymes are available, these structures are insufficient to define how release of basal autoinhibition is coupled to phosphorylation-dependent enzyme activation. Here, we describe the first high-resolution structure of a full-length PLC-γ isozyme and use it to underpin a detailed model of their membrane-dependent regulation. Notably, an interlinked set of regulatory domains integrates basal autoinhibition, tyrosine kinase engagement, and additional scaffolding functions with the phosphorylation-dependent, allosteric control of phospholipase activation. The model also explains why mutant forms of the PLC-γ isozymes found in several cancers have a wide spectrum of activities, and highlights how these activities are tuned during disease.
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Affiliation(s)
- Nicole Hajicek
- Department of PharmacologyThe University of North Carolina at Chapel HillChapel HillUnited States
| | - Nicholas C Keith
- Department of PharmacologyThe University of North Carolina at Chapel HillChapel HillUnited States
| | - Edhriz Siraliev-Perez
- Department of Biochemistry and BiophysicsThe University of North Carolina at Chapel HillChapel HillUnited States
| | - Brenda RS Temple
- Department of Biochemistry and BiophysicsThe University of North Carolina at Chapel HillChapel HillUnited States
- R L Juliano Structural Bioinformatics Core FacilityThe University of North Carolina at Chapel HillChapel HillUnited States
| | - Weigang Huang
- Division of Chemical Biology and Medicinal ChemistryThe University of North Carolina at Chapel HillChapel HillUnited States
| | - Qisheng Zhang
- Department of PharmacologyThe University of North Carolina at Chapel HillChapel HillUnited States
- Division of Chemical Biology and Medicinal ChemistryThe University of North Carolina at Chapel HillChapel HillUnited States
- Lineberger Comprehensive Cancer CenterThe University of North Carolina at Chapel HillChapel HillUnited States
| | - T Kendall Harden
- Department of PharmacologyThe University of North Carolina at Chapel HillChapel HillUnited States
| | - John Sondek
- Department of PharmacologyThe University of North Carolina at Chapel HillChapel HillUnited States
- Department of Biochemistry and BiophysicsThe University of North Carolina at Chapel HillChapel HillUnited States
- Lineberger Comprehensive Cancer CenterThe University of North Carolina at Chapel HillChapel HillUnited States
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12
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Varandas PAMM, Cobb AJA, Segundo MA, Silva EMP. Emergent Glycerophospholipid Fluorescent Probes: Synthesis and Applications. Bioconjug Chem 2019; 31:417-435. [DOI: 10.1021/acs.bioconjchem.9b00660] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Pedro A. M. M. Varandas
- LAQV, REQUIMTE, Department of Chemistry Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Alexander J. A. Cobb
- Department of Chemistry, King’s College London, 7 Trinity Street, London SE1 1DB, United Kingdom
| | - Marcela A. Segundo
- LAQV, REQUIMTE, Department of Chemistry Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Eduarda M. P. Silva
- LAQV, REQUIMTE, Department of Chemistry Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
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13
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Falarz L, Xu Y, Singer SD, Chen G. A Fluorescence-Based Assay for Quantitative Analysis of Phospholipid:Diacylglycerol Acyltransferase Activity. Lipids 2019; 54:571-579. [PMID: 31478204 DOI: 10.1002/lipd.12190] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 08/14/2019] [Accepted: 08/15/2019] [Indexed: 12/23/2022]
Abstract
Phospholipid:diacylglycerol acyltransferase (PDAT) catalyzes the acyl-CoA-independent triacylglycerol (TAG) biosynthesis in plants and oleaginous microorganisms and thus is a key target in lipid research. The conventional in vitro PDAT activity assay involves the use of radiolabeled substrates, which, however, are expensive and demand strict regulation. In this study, a reliable fluorescence-based method using nitrobenzoxadiazole-labeled diacylglycerol (NBD-DAG) as an alternative substrate was established and subsequently used to characterize the enzyme activity and kinetics of a recombinant Arabidopsis thaliana PDAT1 (AtPDAT1). We also demonstrate that the highly toxic benzene used in typical PDAT assays can be substituted with diethyl ether without affecting the formation rate of NBD-TAG. Overall, this method works well with a broad range of PDAT protein content and shows linear correlation with the conventional method with radiolabeled substrates, and thus may be applicable to PDAT from various plant and microorganism species.
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Affiliation(s)
- Lucas Falarz
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada, T6G 2P5.,Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada, R3T 2N2
| | - Yang Xu
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada, T6G 2P5
| | - Stacy D Singer
- Agriculture and Agri-Food Canada, Lethbridge Research and Development Centre, Lethbridge, AB, Canada, T1J 4B1
| | - Guanqun Chen
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada, T6G 2P5.,Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada, R3T 2N2
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14
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Suenami S, Miyazaki R, Kubo T. Detection of Phospholipase C Activity in the Brain Homogenate from the Honeybee. J Vis Exp 2018. [PMID: 30272662 DOI: 10.3791/58173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The honeybee is a model organism for evaluating complex behaviors and higher brain function, such as learning, memory, and division of labor. The mushroom body (MB) is a higher brain center proposed to be the neural substrate of complex honeybee behaviors. Although previous studies identified genes and proteins that are differentially expressed in the MBs and other brain regions, the activities of the proteins in each region are not yet fully understood. To reveal the functions of these proteins in the brain, pharmacologic analysis is a feasible approach, but it is first necessary to confirm that pharmacologic manipulations indeed alter the protein activity in these brain regions. We previously identified a higher expression of genes encoding phospholipase C (PLC) in the MBs than in other brain regions, and pharmacologically assessed the involvement of PLC in honeybee behavior. In that study, we biochemically tested two pharmacologic agents and confirmed that they decreased PLC activity in the MBs and other brain regions. Here, we present a detailed description of how to detect PLC activity in honeybee brain homogenate. In this assay system, homogenates derived from different brain regions are reacted with a synthetic fluorogenic substrate, and fluorescence resulting from PLC activity is quantified and compared between brain regions. We also describe our evaluation of the inhibitory effects of certain drugs on PLC activity using the same system. Although this system is likely affected by other endogenous fluorescence compounds and/or the absorbance of the assay components and tissues, the measurement of PLC activity using this system is safer and easier than that using the traditional assay, which requires radiolabeled substrates. The simple procedure and manipulations allow us to examine PLC activity in the brains and other tissues of honeybees involved in different social tasks.
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Affiliation(s)
- Shota Suenami
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology; Department of Biological Sciences, Graduate School of Science, The University of Tokyo;
| | - Ryo Miyazaki
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology
| | - Takeo Kubo
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo
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