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Maghsoudi S, Shuaib R, Van Bastelaere B, Dakshinamurti S. Adenylyl cyclase isoforms 5 and 6 in the cardiovascular system: complex regulation and divergent roles. Front Pharmacol 2024; 15:1370506. [PMID: 38633617 PMCID: PMC11021717 DOI: 10.3389/fphar.2024.1370506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Accepted: 03/11/2024] [Indexed: 04/19/2024] Open
Abstract
Adenylyl cyclases (ACs) are crucial effector enzymes that transduce divergent signals from upstream receptor pathways and are responsible for catalyzing the conversion of ATP to cAMP. The ten AC isoforms are categorized into four main groups; the class III or calcium-inhibited family of ACs comprises AC5 and AC6. These enzymes are very closely related in structure and have a paucity of selective activators or inhibitors, making it difficult to distinguish them experimentally. AC5 and AC6 are highly expressed in the heart and vasculature, as well as the spinal cord and brain; AC6 is also abundant in the lungs, kidney, and liver. However, while AC5 and AC6 have similar expression patterns with some redundant functions, they have distinct physiological roles due to differing regulation and cAMP signaling compartmentation. AC5 is critical in cardiac and vascular function; AC6 is a key effector of vasodilatory pathways in vascular myocytes and is enriched in fetal/neonatal tissues. Expression of both AC5 and AC6 decreases in heart failure; however, AC5 disruption is cardio-protective, while overexpression of AC6 rescues cardiac function in cardiac injury. This is a comprehensive review of the complex regulation of AC5 and AC6 in the cardiovascular system, highlighting overexpression and knockout studies as well as transgenic models illuminating each enzyme and focusing on post-translational modifications that regulate their cellular localization and biological functions. We also describe pharmacological challenges in the design of isoform-selective activators or inhibitors for AC5 and AC6, which may be relevant to developing new therapeutic approaches for several cardiovascular diseases.
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Affiliation(s)
- Saeid Maghsoudi
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB, Canada
- Biology of Breathing Group, Children’s Hospital Research Institute of Manitoba, Winnipeg, MB, Canada
| | - Rabia Shuaib
- Biology of Breathing Group, Children’s Hospital Research Institute of Manitoba, Winnipeg, MB, Canada
| | - Ben Van Bastelaere
- Biology of Breathing Group, Children’s Hospital Research Institute of Manitoba, Winnipeg, MB, Canada
| | - Shyamala Dakshinamurti
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB, Canada
- Biology of Breathing Group, Children’s Hospital Research Institute of Manitoba, Winnipeg, MB, Canada
- Section of Neonatology, Department of Pediatrics, Health Sciences Centre, Winnipeg, MB, Canada
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2
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Schuster D, Khanppnavar B, Kantarci I, Mehta V, Korkhov VM. Structural insights into membrane adenylyl cyclases, initiators of cAMP signaling. Trends Biochem Sci 2024; 49:156-168. [PMID: 38158273 DOI: 10.1016/j.tibs.2023.12.002] [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: 09/11/2023] [Revised: 12/04/2023] [Accepted: 12/04/2023] [Indexed: 01/03/2024]
Abstract
Membrane adenylyl cyclases (ACs) catalyze the conversion of ATP to the ubiquitous second messenger cAMP. As effector proteins of G protein-coupled receptors and other signaling pathways, ACs receive and amplify signals from the cell surface, translating them into biochemical reactions in the intracellular space and integrating different signaling pathways. Despite their importance in signal transduction and physiology, our knowledge about the structure, function, regulation, and molecular interactions of ACs remains relatively scarce. In this review, we summarize recent advances in our understanding of these membrane enzymes.
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Affiliation(s)
- Dina Schuster
- Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institute, Villigen, Switzerland; Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Switzerland; Department of Biology, Institute of Molecular Systems Biology, ETH Zurich, Switzerland
| | - Basavraj Khanppnavar
- Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institute, Villigen, Switzerland; Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Switzerland
| | - Ilayda Kantarci
- Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institute, Villigen, Switzerland
| | - Ved Mehta
- Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institute, Villigen, Switzerland
| | - Volodymyr M Korkhov
- Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institute, Villigen, Switzerland; Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Switzerland.
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3
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Dwyer TS, O’Brien JB, Ptak CP, LaVigne JE, Flaherty DP, Watts VJ, Roman DL. Protein-protein interaction-based high throughput screening for adenylyl cyclase 1 inhibitors: Design, implementation, and discovery of a novel chemotype. Front Pharmacol 2022; 13:977742. [PMID: 36147328 PMCID: PMC9486168 DOI: 10.3389/fphar.2022.977742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 08/08/2022] [Indexed: 11/25/2022] Open
Abstract
Genetic and preclinical studies have implicated adenylyl cyclase 1 (AC1) as a potential target for the treatment of chronic inflammatory pain. AC1 activity is increased following inflammatory pain stimuli and AC1 knockout mice show a marked reduction in responses to inflammatory pain. Previous drug discovery efforts have centered around the inhibition of AC1 activity in cell-based assays. In the present study, we used an in vitro approach focused on inhibition of the protein-protein interaction (PPI) between Ca2+/calmodulin (CaM) and AC1, an interaction that is required for activation of AC1. We developed a novel fluorescence polarization (FP) assay focused on the PPI between an AC1 peptide and CaM and used this assay to screen over 23,000 compounds for inhibitors of the AC1-CaM PPI. Next, we used a cellular NanoBiT assay to validate 21 FP hits for inhibition of the AC1-CaM PPI in a cellular context with full-length proteins. Based on efficacy, potency, and selectivity for AC1, hits 12, 13, 15, 18, 20, and 21 were prioritized. We then tested these compounds for inhibition of AC1 activity in cyclic AMP (cAMP) accumulation assays, using HEK293 cells stably expressing AC1. Hit 15 contained a dithiophene scaffold and was of particular interest because it shared structural similarities with our recently reported benzamide series of AC1 inhibitors. We next tested a small set of 13 compounds containing the dithiophene scaffold for structure-activity relationship studies. Although many compounds were non-selective, we observed trends for tuning AC1/AC8 selectivity based on heterocycle type and substituents. Having an ethyl on the central thiophene caused the scaffold to be more selective for AC8. Cyclization of the alkyl substituent fused to the thiophene significantly reduced activity and also shifted selectivity toward AC8. Notably, combining the fused cyclohexane-thiophene ring system with a morpholine heterocycle significantly increased potency at both AC1 and AC8. Through designing a novel FP screen and NanoBiT assay, and evaluating hits in cAMP accumulation assays, we have discovered a novel, potent, dithiophene scaffold for inhibition of the AC1- and AC8-CaM PPI. We also report the most potent fully efficacious inhibitor of AC8 activity known to-date.
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Affiliation(s)
- Tiffany S. Dwyer
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN, United States
| | - Joseph B. O’Brien
- Department of Pharmaceutical Sciences & Experimental Therapeutics, The University of Iowa College of Pharmacy, Iowa City, IA, United States
| | - Christopher P. Ptak
- Nuclear Magnetic Resonance Facility, The University of Iowa Carver College of Medicine, Iowa City, IA, United States
| | - Justin E. LaVigne
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN, United States
| | - Daniel P. Flaherty
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN, United States
- Purdue Institute for Drug Discovery, West Lafayette, IN, United States
- Purdue Institute for Integrative Neuroscience, West Lafayette, IN, United States
| | - Val J. Watts
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN, United States
- Purdue Institute for Drug Discovery, West Lafayette, IN, United States
- Purdue Institute for Integrative Neuroscience, West Lafayette, IN, United States
| | - David L. Roman
- Department of Pharmaceutical Sciences & Experimental Therapeutics, The University of Iowa College of Pharmacy, Iowa City, IA, United States
- Iowa Neuroscience Institute, Iowa City, IA, United States
- Holden Comprehensive Cancer Center, The University of Iowa Hospitals & Clinics, Iowa City, IA, United States
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4
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van Keulen SC, Martin J, Colizzi F, Frezza E, Trpevski D, Diaz NC, Vidossich P, Rothlisberger U, Hellgren Kotaleski J, Wade RC, Carloni P. Multiscale molecular simulations to investigate adenylyl cyclase‐based signaling in the brain. WIRES COMPUTATIONAL MOLECULAR SCIENCE 2022. [DOI: 10.1002/wcms.1623] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Siri C. van Keulen
- Computational Structural Biology Group, Bijvoet Center for Biomolecular Research, Science for Life, Faculty of Science – Chemistry Utrecht University Utrecht The Netherlands
| | - Juliette Martin
- CNRS, UMR 5086 Molecular Microbiology and Structural Biochemistry University of Lyon Lyon France
| | - Francesco Colizzi
- Molecular Ocean Laboratory, Department of Marine Biology and Oceanography Institute of Marine Sciences, ICM‐CSIC Barcelona Spain
| | - Elisa Frezza
- Université Paris Cité, CiTCoM, CNRS Paris France
| | - Daniel Trpevski
- Science for Life Laboratory, School of Electrical Engineering and Computer Science KTH Royal Institute of Technology Stockholm
| | - Nuria Cirauqui Diaz
- CNRS, UMR 5086 Molecular Microbiology and Structural Biochemistry University of Lyon Lyon France
| | - Pietro Vidossich
- Molecular Modeling and Drug Discovery Lab Istituto Italiano di Tecnologia Genoa Italy
| | - Ursula Rothlisberger
- Laboratory of Computational Chemistry and Biochemistry Ecole Polytechnique Fédérale de Lausanne (EPFL) Lausanne
| | - Jeanette Hellgren Kotaleski
- Science for Life Laboratory, School of Electrical Engineering and Computer Science KTH Royal Institute of Technology Stockholm
- Department of Neuroscience Karolinska Institute Stockholm
| | - Rebecca C. Wade
- Molecular and Cellular Modeling Group Heidelberg Institute for Theoretical Studies (HITS) Heidelberg Germany
- Center for Molecular Biology (ZMBH), DKFZ‐ZMBH Alliance, and Interdisciplinary Center for Scientific Computing (IWR) Heidelberg University Heidelberg Germany
| | - Paolo Carloni
- Institute for Neuroscience and Medicine (INM‐9) and Institute for Advanced Simulations (IAS‐5) “Computational biomedicine” Forschungszentrum Jülich Jülich Germany
- INM‐11 JARA‐Institute: Molecular Neuroscience and Neuroimaging Forschungszentrum Jülich Jülich Germany
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5
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Ostrom KF, LaVigne JE, Brust TF, Seifert R, Dessauer CW, Watts VJ, Ostrom RS. Physiological roles of mammalian transmembrane adenylyl cyclase isoforms. Physiol Rev 2022; 102:815-857. [PMID: 34698552 PMCID: PMC8759965 DOI: 10.1152/physrev.00013.2021] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 09/20/2021] [Accepted: 10/19/2021] [Indexed: 12/12/2022] Open
Abstract
Adenylyl cyclases (ACs) catalyze the conversion of ATP to the ubiquitous second messenger cAMP. Mammals possess nine isoforms of transmembrane ACs, dubbed AC1-9, that serve as major effector enzymes of G protein-coupled receptors (GPCRs). The transmembrane ACs display varying expression patterns across tissues, giving the potential for them to have a wide array of physiological roles. Cells express multiple AC isoforms, implying that ACs have redundant functions. Furthermore, all transmembrane ACs are activated by Gαs, so it was long assumed that all ACs are activated by Gαs-coupled GPCRs. AC isoforms partition to different microdomains of the plasma membrane and form prearranged signaling complexes with specific GPCRs that contribute to cAMP signaling compartments. This compartmentation allows for a diversity of cellular and physiological responses by enabling unique signaling events to be triggered by different pools of cAMP. Isoform-specific pharmacological activators or inhibitors are lacking for most ACs, making knockdown and overexpression the primary tools for examining the physiological roles of a given isoform. Much progress has been made in understanding the physiological effects mediated through individual transmembrane ACs. GPCR-AC-cAMP signaling pathways play significant roles in regulating functions of every cell and tissue, so understanding each AC isoform's role holds potential for uncovering new approaches for treating a vast array of pathophysiological conditions.
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Affiliation(s)
| | - Justin E LaVigne
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana
| | - Tarsis F Brust
- Department of Pharmaceutical Sciences, Lloyd L. Gregory School of Pharmacy, Palm Beach Atlantic University, West Palm Beach, Florida
| | - Roland Seifert
- Institute of Pharmacology, Hannover Medical School, Hannover, Germany
| | - Carmen W Dessauer
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Sciences Center at Houston, Houston, Texas
| | - Val J Watts
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana
- Purdue Institute for Drug Discovery, Purdue University, West Lafayette, Indiana
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana
| | - Rennolds S Ostrom
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California
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6
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Colizzi F, Orozco M. Probing allosteric regulations with coevolution-driven molecular simulations. SCIENCE ADVANCES 2021; 7:eabj0786. [PMID: 34516882 PMCID: PMC8442858 DOI: 10.1126/sciadv.abj0786] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 07/19/2021] [Indexed: 06/13/2023]
Abstract
Protein-mediated allosteric regulations are essential in biology, but their quantitative characterization continues to posit formidable challenges for both experiments and computations. Here, we combine coevolutionary information, multiscale molecular simulations, and free-energy methods to interrogate and quantify the allosteric regulation of functional changes in protein complexes. We apply this approach to investigate the regulation of adenylyl cyclase (AC) by stimulatory and inhibitory G proteins—a prototypical allosteric system that has long escaped from in-depth molecular characterization. We reveal a surprisingly simple ON/OFF regulation of AC functional dynamics through multiple pathways of information transfer. The binding of G proteins reshapes the free-energy landscape of AC following the classical population-shift paradigm. The model agrees with structural and biochemical data and reveals previously unknown experimentally consistent intermediates. Our approach showcases a general strategy to explore uncharted functional space in complex biomolecular regulations.
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Affiliation(s)
- Francesco Colizzi
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona Institute of Science and Technology (BIST), Carrer de Baldiri Reixac 10, Barcelona 08028, Spain
| | - Modesto Orozco
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona Institute of Science and Technology (BIST), Carrer de Baldiri Reixac 10, Barcelona 08028, Spain
- Departament de Bioquímica i Biomedicina, Facultat de Biologia, Universitat de Barcelona, Avinguda Diagonal 647, Barcelona 08028, Spain
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7
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Cross-Talk Between the Adenylyl Cyclase/cAMP Pathway and Ca 2+ Homeostasis. Rev Physiol Biochem Pharmacol 2021; 179:73-116. [PMID: 33398503 DOI: 10.1007/112_2020_55] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cyclic AMP and Ca2+ are the first second or intracellular messengers identified, unveiling the cellular mechanisms activated by a plethora of extracellular signals, including hormones. Cyclic AMP generation is catalyzed by adenylyl cyclases (ACs), which convert ATP into cAMP and pyrophosphate. By the way, Ca2+, as energy, can neither be created nor be destroyed; Ca2+ can only be transported, from one compartment to another, or chelated by a variety of Ca2+-binding molecules. The fine regulation of cytosolic concentrations of cAMP and free Ca2+ is crucial in cell function and there is an intimate cross-talk between both messengers to fine-tune the cellular responses. Cancer is a multifactorial disease resulting from a combination of genetic and environmental factors. Frequent cases of cAMP and/or Ca2+ homeostasis remodeling have been described in cancer cells. In those tumoral cells, cAMP and Ca2+ signaling plays a crucial role in the development of hallmarks of cancer, including enhanced proliferation and migration, invasion, apoptosis resistance, or angiogenesis. This review summarizes the cross-talk between the ACs/cAMP and Ca2+ intracellular pathways with special attention to the functional and reciprocal regulation between Orai1 and AC8 in normal and cancer cells.
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8
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Khannpnavar B, Mehta V, Qi C, Korkhov V. Structure and function of adenylyl cyclases, key enzymes in cellular signaling. Curr Opin Struct Biol 2020; 63:34-41. [PMID: 32334344 DOI: 10.1016/j.sbi.2020.03.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 03/01/2020] [Accepted: 03/06/2020] [Indexed: 12/19/2022]
Abstract
The adenylyl cyclases (ACs) catalyze the production of the ubiquitous second messenger, cAMP, which in turns acts on a number of effectors and thus regulates a plethora of cellular functions. As the key enzymes in the highly evolutionarily conserved cAMP pathway, the ACs control the physiology of the cells, tissues, organs and organisms in health and disease. A comprehensive understanding of the specific role of the ACs in these processes of life requires a deep mechanistic understanding of structure and mechanisms of action of these enzymes. Here we highlight the exciting recent reports on the biochemistry and structure and higher order organization of the ACs and their signaling complexes. These studies have provided the glimpses into the principles of the AC-mediated homeostatic control of cellular physiology.
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Affiliation(s)
- Basavraj Khannpnavar
- Institute of Biochemistry, ETH Zurich, Switzerland; Laboratory of Biomolecular Research, Paul Scherrer Institute, Villigen 5232, Switzerland
| | - Ved Mehta
- Laboratory of Biomolecular Research, Paul Scherrer Institute, Villigen 5232, Switzerland
| | - Chao Qi
- Institute of Biochemistry, ETH Zurich, Switzerland; Laboratory of Biomolecular Research, Paul Scherrer Institute, Villigen 5232, Switzerland
| | - Volodymyr Korkhov
- Institute of Biochemistry, ETH Zurich, Switzerland; Laboratory of Biomolecular Research, Paul Scherrer Institute, Villigen 5232, Switzerland.
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9
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Butryn A, Raza H, Rada H, Moraes I, Owens RJ, Orville AM. Molecular basis for GTP recognition by light-activated guanylate cyclase RhGC. FEBS J 2019; 287:2797-2807. [PMID: 31808997 PMCID: PMC7384201 DOI: 10.1111/febs.15167] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 11/23/2019] [Accepted: 12/05/2019] [Indexed: 11/27/2022]
Abstract
Cyclic guanosine 3',5'-monophosphate (cGMP) is an intracellular signalling molecule involved in many sensory and developmental processes. Synthesis of cGMP from GTP is catalysed by guanylate cyclase (GC) in a reaction analogous to cAMP formation by adenylate cyclase (AC). Although detailed structural information is available on the catalytic region of nucleotidyl cyclases (NCs) in various states, these atomic models do not provide a sufficient explanation for the substrate selectivity between GC and AC family members. Detailed structural information on the GC domain in its active conformation is largely missing, and no crystal structure of a GTP-bound wild-type GC domain has been published to date. Here, we describe the crystal structure of the catalytic domain of rhodopsin-GC (RhGC) from Catenaria anguillulae in complex with GTP at 1.7 Å resolution. Our study reveals the organization of a eukaryotic GC domain in its active conformation. We observe that the binding mode of the substrate GTP is similar to that of AC-ATP interaction, although surprisingly not all of the interactions predicted to be responsible for base recognition are present. The structure provides insights into potential mechanisms of substrate discrimination and activity regulation that may be common to all class III purine NCs. DATABASE: Structural data are available in Protein Data Bank database under the accession number 6SIR. ENZYMES: EC4.6.1.2.
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Affiliation(s)
- Agata Butryn
- Diamond Light Source Limited, Didcot, UK.,Research Complex at Harwell, Didcot, UK
| | - Hadeeqa Raza
- Diamond Light Source Limited, Didcot, UK.,Research Complex at Harwell, Didcot, UK
| | - Heather Rada
- Protein Production UK, Research Complex at Harwell, Didcot, UK
| | - Isabel Moraes
- Research Complex at Harwell, Didcot, UK.,Membrane Protein Laboratory, Diamond Light Source Limited, Didcot, UK
| | - Raymond J Owens
- Protein Production UK, Research Complex at Harwell, Didcot, UK
| | - Allen M Orville
- Diamond Light Source Limited, Didcot, UK.,Research Complex at Harwell, Didcot, UK
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10
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van Keulen SC, Narzi D, Rothlisberger U. Association of Both Inhibitory and Stimulatory Gα Subunits Implies Adenylyl Cyclase 5 Deactivation. Biochemistry 2019; 58:4317-4324. [PMID: 31525953 DOI: 10.1021/acs.biochem.9b00662] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Adenylyl cyclase (AC) generates cyclic AMP required for a variety of cellular functions, and its regulation plays a major role in cellular signal transduction in eukaryotes and prokaryotes. All membrane-bound AC isoforms in eukaryotes can be activated by stimulatory G-proteins, but only AC1, AC5, and AC6 can be both stimulated and inhibited by active Gα subunits, Gαs and Gαi, respectively. In principle, these Gαi-sensitive AC isoforms could form both binary and ternary complexes with Gα subunits due to the noncompetitive association of inhibitory and stimulatory Gα. However, the formation and possible catalytic activity of a putative ternary complex have not yet been experimentally confirmed due to its proposed short-lived nature. Here, the catalytic activity of such a ternary complex consisting of apo AC5, stimulatory Gαolf, and inhibitory Gαi1 is investigated via classical molecular dynamics simulations. Trajectories of inhibited and stimulated binary complexes, AC5:Gαi1 and AC5:Gαolf, respectively, as well as Gα-free AC5 were also obtained to compare the sampled AC5 conformation in the ternary complex to those sampled under different Gα conditions. This comparison suggests that association of both Gα subunits results in an AC5 conformation similar to that sampled by the AC5:Gαi1 complex, indicating that the ternary complex mainly samples an inactive conformation.
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Affiliation(s)
- Siri C van Keulen
- Institut des Sciences et Ingénierie Chimiques , Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne , Switzerland.,Computational Structural Biology Group, Bijvoet Center for Biomolecular Research , Utrecht University , 3584 CH Utrecht , Netherlands
| | - Daniele Narzi
- Institut des Sciences et Ingénierie Chimiques , Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne , Switzerland
| | - Ursula Rothlisberger
- Institut des Sciences et Ingénierie Chimiques , Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne , Switzerland
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11
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Kaur J, Soto-Velasquez M, Ding Z, Ghanbarpour A, Lill MA, van Rijn RM, Watts VJ, Flaherty DP. Optimization of a 1,3,4-oxadiazole series for inhibition of Ca 2+/calmodulin-stimulated activity of adenylyl cyclases 1 and 8 for the treatment of chronic pain. Eur J Med Chem 2019; 162:568-585. [PMID: 30472604 PMCID: PMC6310635 DOI: 10.1016/j.ejmech.2018.11.036] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 11/12/2018] [Accepted: 11/15/2018] [Indexed: 12/28/2022]
Abstract
Adenylyl cyclases type 1 (AC1) and 8 (AC8) are group 1 transmembrane adenylyl cyclases (AC) that are stimulated by Ca2+/calmodulin. Studies have shown that mice depleted of AC1 have attenuated inflammatory pain response, while AC1/AC8 double-knockout mice display both attenuated pain response and opioid dependence. Thus, AC1 has emerged as a promising new target for treating chronic pain and opioid abuse. We discovered that the 1,3,4-oxadiazole scaffold inhibits Ca2+/calmodulin-stimulated cyclic adenosine 3',5'-monophosphate (cAMP) production in cells stably expressing either AC1 or AC8. We then carried out structure-activity relationship studies, in which we designed and synthesized 65 analogs, to modulate potency and selectivity versus each AC isoform in cells. Furthermore, molecular docking of the analogs into an AC1 homology model suggests the molecules may bind at the ATP binding site. Finally, a prioritized analog was tested in a mouse model of inflammatory pain and exhibited modest analgesic properties. In summary, our data indicate the 1,3,4-oxadiazoles represent a novel scaffold for the cellular inhibition of Ca2+/calmodulin-stimulated AC1- and AC8 cAMP and warrant further exploration as potential lead compounds for the treatment of chronic inflammatory pain.
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Affiliation(s)
- Jatinder Kaur
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, 575 Stadium Mall Dr, West Lafayette, IN, 47907, USA
| | - Monica Soto-Velasquez
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, 575 Stadium Mall Dr, West Lafayette, IN, 47907, USA
| | - Zhong Ding
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, 575 Stadium Mall Dr, West Lafayette, IN, 47907, USA
| | - Ahmadreza Ghanbarpour
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, 575 Stadium Mall Dr, West Lafayette, IN, 47907, USA
| | - Markus A Lill
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, 575 Stadium Mall Dr, West Lafayette, IN, 47907, USA; Purdue Institute for Drug Discovery, Purdue University, West Lafayette, IN, 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, 47907, USA
| | - Richard M van Rijn
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, 575 Stadium Mall Dr, West Lafayette, IN, 47907, USA; Purdue Institute for Drug Discovery, Purdue University, West Lafayette, IN, 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, 47907, USA
| | - Val J Watts
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, 575 Stadium Mall Dr, West Lafayette, IN, 47907, USA; Purdue Institute for Drug Discovery, Purdue University, West Lafayette, IN, 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, 47907, USA
| | - Daniel P Flaherty
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, 575 Stadium Mall Dr, West Lafayette, IN, 47907, USA; Purdue Institute for Drug Discovery, Purdue University, West Lafayette, IN, 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, 47907, USA.
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12
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Oh J, Hong JI. Cation Effect on Fluorescent Sensing of Pyrophosphate by a Bis(Zn-DPA) Probe. B KOREAN CHEM SOC 2018. [DOI: 10.1002/bkcs.11494] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Jinrok Oh
- Department of Chemistry; Seoul National University; Seoul 08826 South Korea
| | - Jong-In Hong
- Department of Chemistry; Seoul National University; Seoul 08826 South Korea
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13
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Wiggins SV, Steegborn C, Levin LR, Buck J. Pharmacological modulation of the CO 2/HCO 3-/pH-, calcium-, and ATP-sensing soluble adenylyl cyclase. Pharmacol Ther 2018; 190:173-186. [PMID: 29807057 DOI: 10.1016/j.pharmthera.2018.05.008] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Cyclic AMP (cAMP), the prototypical second messenger, has been implicated in a wide variety of (often opposing) physiological processes. It simultaneously mediates multiple, diverse processes, often within a single cell, by acting locally within independently-regulated and spatially-restricted microdomains. Within each microdomain, the level of cAMP will be dependent upon the balance between its synthesis by adenylyl cyclases and its degradation by phosphodiesterases (PDEs). In mammalian cells, there are many PDE isoforms and two types of adenylyl cyclases; the G protein regulated transmembrane adenylyl cyclases (tmACs) and the CO2/HCO3-/pH-, calcium-, and ATP-sensing soluble adenylyl cyclase (sAC). Discriminating the roles of individual cyclic nucleotide microdomains requires pharmacological modulators selective for the various PDEs and/or adenylyl cyclases. Such tools present an opportunity to develop therapeutics specifically targeted to individual cAMP dependent pathways. The pharmacological modulators of tmACs have recently been reviewed, and in this review, we describe the current status of pharmacological tools available for studying sAC.
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Affiliation(s)
- Shakarr V Wiggins
- Graduate Program in Neuroscience, Weill Cornell Medicine, New York, NY 10065, United States
| | - Clemens Steegborn
- Department of Biochemistry, University of Bayreuth, 95440 Bayreuth, Germany
| | - Lonny R Levin
- Department of Pharmacology, Weill Cornell Medicine, New York, NY 10065, United States.
| | - Jochen Buck
- Department of Pharmacology, Weill Cornell Medicine, New York, NY 10065, United States
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Moore ER, Ryu HS, Zhu YX, Jacobs CR. Adenylyl cyclases and TRPV4 mediate Ca 2+/cAMP dynamics to enhance fluid flow-induced osteogenesis in osteocytes. JOURNAL OF MOLECULAR BIOCHEMISTRY 2018; 7:48-59. [PMID: 31123666 PMCID: PMC6529196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Bone adapts to physical forces and this process is dependent on osteocyte mechanotransduction. One way osteocytes sense mechanical stimulation is through the primary cilium, a sensory organelle that triggers intracellular signaling cascades in response to fluid shear. Our lab previously determined that flow-induced ciliary Ca2+ influx and changes in cytosolic cAMP levels are critical for osteogenesis. We also identified two proteins important for osteocyte mechanotransduction: transient receptor potential vanilloid 4 (TRPV4) and adenylyl cyclase 6 (AC6). Interestingly, disrupting the Ca2+-binding ability of these proteins results in loss of function. Although knockdowns of TRPV4 and AC6 disrupt osteogenesis, there is no definitive evidence linking them to Ca2+/cAMP dynamics that facilitate osteocyte mechanotransduction. We therefore transfected MLO-Y4 osteocytes with AC3/6 and TRPV4 overexpression plasmids that fail to interact with Ca2+ and observed the response to fluid shear. Indeed, mutant groups exhibited adverse changes in cAMP and lower mRNA expression of an osteogenic marker, COX-2, at the onset of flow. This pattern persisted for AC3 and TRPV4 but we detected no difference in AC6 at longer exposure to flow. These results suggest TRPV4 and ACs mediate Ca2+/cAMP dynamics that are important for osteocyte mechanotransduction. These mechanisms are potential targets for therapeutics to combat bone loss and should be investigated further.
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Synthesis and degradation of cAMP in Giardia lamblia: possible role and characterization of a nucleotidyl cyclase with a single cyclase homology domain. Biochem J 2017; 474:4001-4017. [PMID: 29054977 DOI: 10.1042/bcj20170590] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 10/17/2017] [Accepted: 10/19/2017] [Indexed: 01/25/2023]
Abstract
Despite its importance in the regulation of growth and differentiation processes of a variety of organisms, the mechanism of synthesis and degradation of cAMP (cyclic AMP) has not yet been described in Giardia lamblia In this work, we measured significant quantities of cAMP in trophozoites of G. lamblia incubated in vitro and later detected how it increases during the first hours of encystation, and how it then returns to basal levels at 24 h. Through an analysis of the genome of G. lamblia, we found sequences of three putative enzymes - one phosphodiesterase (gPDE) and two nucleotidyl cyclases (gNC1 and gNC2) - that should be responsible for the regulation of cAMP in G. lamblia Later, an RT-PCR assay confirmed that these three genes are expressed in trophozoites. The bioinformatic analysis indicated that gPDE is a transmembrane protein of 154 kDa, with a single catalytic domain in the C-terminal end; gNC1 is predicted to be a transmembrane protein of 74 kDa, with only one class III cyclase homology domain (CHD) at the C-terminal end; and gNC2 should be a transmembrane protein of 246 kDa, with two class III CHDs. Finally, we cloned and enriched the catalytic domain of gNC1 (gNC1cd) from bacteria. After that, we confirmed that gNC1cd has adenylyl cyclase (AC) activity. This enzymatic activity depends on the presence of Mn2+ and Ca2+, but no significant activity was displayed in the presence of Mg2+ Additionally, the AC activity of gNC1cd is competitively inhibited with GTP, so it is highly possible that gNC1 has guanylyl cyclase activity as well.
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Abstract
Mammalian membranous and soluble adenylyl cyclases (mAC, sAC) and soluble guanylyl cyclases (sGC) generate cAMP and cGMP from ATP and GTP, respectively, as substrates. mACs (nine human isoenzymes), sAC, and sGC differ in their overall structures owing to specific membrane-spanning and regulatory domains but consist of two similarly folded catalytic domains C1 and C2 with high structure-based homology between the cyclase species. Comparison of available crystal structures - VC1:IIC2 (a construct of domains C1a from dog mAC5 and C2a from rat mAC2), human sAC and sGC, mostly in complex with substrates, substrate analogs, inhibitors, metal ions, and/or modulators - reveals that especially the nucleotide binding sites are closely related. An evolutionarily well-conserved catalytic mechanism is based on common binding modes, interactions, and structural transformations, including the participation of two metal ions in catalysis. Nucleobase selectivity relies on only few mutations. Since in all cases the nucleoside moiety is embedded in a relatively spacious cavity, mACs, sAC, and sGC are rather promiscuous and bind nearly all purine and pyrimidine nucleotides, including CTP and UTP, and many of their derivatives as inhibitors with often high affinity. By contrast, substrate specificity of mammalian adenylyl and guanylyl cyclases is high due to selective dynamic rearrangements during turnover.
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17
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Qualls-Creekmore E, Gupta R, Yoshimura M. The effect of alcohol on recombinant proteins derived from mammalian adenylyl cyclase. Biochem Biophys Rep 2017; 10:157-164. [PMID: 28955743 PMCID: PMC5614657 DOI: 10.1016/j.bbrep.2017.03.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 03/07/2017] [Accepted: 03/29/2017] [Indexed: 11/26/2022] Open
Abstract
The cyclic AMP (cAMP) signaling pathway is implicated in the development of alcohol use disorder. Previous studies have demonstrated that ethanol enhances the activity of adenylyl cyclase (AC) in an isoform specific manner; AC7 is most enhanced by ethanol, and regions responsible for enhancement by ethanol are located in the cytoplasmic domains of the AC7 protein. We hypothesize that ethanol modulates AC activity by directly interacting with the protein and that ethanol effects on AC can be studied using recombinant AC in vitro. AC recombinant proteins containing only the C1a or C2 domains of AC7 and AC9 individually were expressed in bacteria, and purified. The purified recombinant AC proteins retained enzymatic activity and isoform specific alcohol responsiveness. The combination of the C1a or C2 domains of AC7 maintained the same alcohol cutoff point as full-length AC7. We also find that the recombinant AC7 responds to alcohol differently in the presence of different combinations of activators including MnCl2, forskolin, and Gsα. Through a series of concentration-response experiments and curve fitting, the values for maximum activities, Hill coefficients, and EC50 were determined in the absence and presence of butanol as a surrogate of ethanol. The results suggest that alcohol modulates AC activity by directly interacting with the AC protein and that the alcohol interaction with the AC protein occurs at multiple sites with positive cooperativity. This study indicates that the recombinant AC proteins expressed in bacteria can provide a useful model system to investigate the mechanism of alcohol action on their activity.
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Affiliation(s)
- Emily Qualls-Creekmore
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, United States
| | - Ratna Gupta
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, United States
| | - Masami Yoshimura
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, United States
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van Keulen SC, Rothlisberger U. Exploring the inhibition mechanism of adenylyl cyclase type 5 by n-terminal myristoylated Gαi1. PLoS Comput Biol 2017; 13:e1005673. [PMID: 28892485 PMCID: PMC5608429 DOI: 10.1371/journal.pcbi.1005673] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Revised: 09/21/2017] [Accepted: 06/26/2017] [Indexed: 11/18/2022] Open
Abstract
Adenylyl cyclase (AC) is an important messenger involved in G-protein-coupled-receptor signal transduction pathways, which is a well-known target for drug development. AC is regulated by activated stimulatory (Gαs) and inhibitory (Gαi) G proteins in the cytosol. Although experimental studies have shown that these Gα subunits can stimulate or inhibit AC's function in a non-competitive way, it is not well understood what the difference is in their mode of action as both Gα subunits appear structurally very similar in a non-lipidated state. However, a significant difference between Gαs and Gαi is that while Gαs does not require any lipidation in order to stimulate AC, N-terminal myristoylation is crucial for Gαi's inhibitory function as AC is not inhibited by non-myristoylated Gαi. At present, only the conformation of the complex including Gαs and AC has been resolved via X-ray crystallography. Therefore, understanding the interaction between Gαi and AC is important as it will provide more insight into the unknown mechanism of AC regulation. This study demonstrates via classical molecular dynamics simulations that the myristoylated Gαi1 structure is able to interact with apo adenylyl cyclase type 5 in a way that causes inhibition of the catalytic function of the enzyme, suggesting that Gα lipidation could play a crucial role in AC regulation and in regulating G protein function by affecting Gαi's active conformation.
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Affiliation(s)
- Siri Camee van Keulen
- Institut des Sciences et Ingénierie Chimiques, École Polytechnicque Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Ursula Rothlisberger
- Institut des Sciences et Ingénierie Chimiques, École Polytechnicque Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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19
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Dessauer CW, Watts VJ, Ostrom RS, Conti M, Dove S, Seifert R. International Union of Basic and Clinical Pharmacology. CI. Structures and Small Molecule Modulators of Mammalian Adenylyl Cyclases. Pharmacol Rev 2017; 69:93-139. [PMID: 28255005 PMCID: PMC5394921 DOI: 10.1124/pr.116.013078] [Citation(s) in RCA: 128] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Adenylyl cyclases (ACs) generate the second messenger cAMP from ATP. Mammalian cells express nine transmembrane AC (mAC) isoforms (AC1-9) and a soluble AC (sAC, also referred to as AC10). This review will largely focus on mACs. mACs are activated by the G-protein Gαs and regulated by multiple mechanisms. mACs are differentially expressed in tissues and regulate numerous and diverse cell functions. mACs localize in distinct membrane compartments and form signaling complexes. sAC is activated by bicarbonate with physiologic roles first described in testis. Crystal structures of the catalytic core of a hybrid mAC and sAC are available. These structures provide detailed insights into the catalytic mechanism and constitute the basis for the development of isoform-selective activators and inhibitors. Although potent competitive and noncompetitive mAC inhibitors are available, it is challenging to obtain compounds with high isoform selectivity due to the conservation of the catalytic core. Accordingly, caution must be exerted with the interpretation of intact-cell studies. The development of isoform-selective activators, the plant diterpene forskolin being the starting compound, has been equally challenging. There is no known endogenous ligand for the forskolin binding site. Recently, development of selective sAC inhibitors was reported. An emerging field is the association of AC gene polymorphisms with human diseases. For example, mutations in the AC5 gene (ADCY5) cause hyperkinetic extrapyramidal motor disorders. Overall, in contrast to the guanylyl cyclase field, our understanding of the (patho)physiology of AC isoforms and the development of clinically useful drugs targeting ACs is still in its infancy.
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Affiliation(s)
- Carmen W Dessauer
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Sciences Center at Houston, Houston, Texas (C.W.D.); Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana (V.J.W.); Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California (R.S.O.); Center for Reproductive Sciences, University of California San Francisco, San Francisco, California (M.C.); Institute of Pharmacy, University of Regensburg, Regensburg, Germany (S.D.); and Institute of Pharmacology, Hannover Medical School, Hannover, Germany (R.S.)
| | - Val J Watts
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Sciences Center at Houston, Houston, Texas (C.W.D.); Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana (V.J.W.); Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California (R.S.O.); Center for Reproductive Sciences, University of California San Francisco, San Francisco, California (M.C.); Institute of Pharmacy, University of Regensburg, Regensburg, Germany (S.D.); and Institute of Pharmacology, Hannover Medical School, Hannover, Germany (R.S.)
| | - Rennolds S Ostrom
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Sciences Center at Houston, Houston, Texas (C.W.D.); Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana (V.J.W.); Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California (R.S.O.); Center for Reproductive Sciences, University of California San Francisco, San Francisco, California (M.C.); Institute of Pharmacy, University of Regensburg, Regensburg, Germany (S.D.); and Institute of Pharmacology, Hannover Medical School, Hannover, Germany (R.S.)
| | - Marco Conti
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Sciences Center at Houston, Houston, Texas (C.W.D.); Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana (V.J.W.); Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California (R.S.O.); Center for Reproductive Sciences, University of California San Francisco, San Francisco, California (M.C.); Institute of Pharmacy, University of Regensburg, Regensburg, Germany (S.D.); and Institute of Pharmacology, Hannover Medical School, Hannover, Germany (R.S.)
| | - Stefan Dove
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Sciences Center at Houston, Houston, Texas (C.W.D.); Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana (V.J.W.); Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California (R.S.O.); Center for Reproductive Sciences, University of California San Francisco, San Francisco, California (M.C.); Institute of Pharmacy, University of Regensburg, Regensburg, Germany (S.D.); and Institute of Pharmacology, Hannover Medical School, Hannover, Germany (R.S.)
| | - Roland Seifert
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Sciences Center at Houston, Houston, Texas (C.W.D.); Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana (V.J.W.); Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California (R.S.O.); Center for Reproductive Sciences, University of California San Francisco, San Francisco, California (M.C.); Institute of Pharmacy, University of Regensburg, Regensburg, Germany (S.D.); and Institute of Pharmacology, Hannover Medical School, Hannover, Germany (R.S.)
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20
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Spirli C, Mariotti V, Villani A, Fabris L, Fiorotto R, Strazzabosco M. Adenylyl cyclase 5 links changes in calcium homeostasis to cAMP-dependent cyst growth in polycystic liver disease. J Hepatol 2017; 66:571-580. [PMID: 27826057 PMCID: PMC5316496 DOI: 10.1016/j.jhep.2016.10.032] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 10/17/2016] [Accepted: 10/23/2016] [Indexed: 12/16/2022]
Abstract
BACKGROUND & AIMS Genetic defects in polycystin-1 or -2 (PC1 or PC2) cause polycystic liver disease associated with autosomal dominant polycystic kidney disease (PLD-ADPKD). Progressive cyst growth is sustained by a cAMP-dependent Ras/ERK/HIFα pathway, leading to increased vascular endothelial growth factor A (VEGF-A) signaling. In PC2-defective cholangiocytes, cAMP production in response to [Ca2+]ER depletion is increased, while store-operated Ca2+ entry (SOCE), intracellular and endoplasmic reticulum [Ca2+]ER levels are reduced. We investigated whether the adenylyl cyclases, AC5 and AC6, which can be inhibited by Ca2+, are activated by the ER chaperone STIM1. This would result in cAMP/PKA-dependent Ras/ERK/HIFα pathway activation in PC2-defective cells, in response to [Ca2+]ER depletion. METHODS PC2/AC6 double conditional knockout (KO) mice were generated (Pkd2/AC6 KO) and compared to Pkd2 KO mice. The AC5 inhibitor SQ22,536 or AC5 siRNA were used in isolated cholangiocytes while the inhibitor was used in biliary organoid and animals; liver tissues were harvested for histochemical analysis. RESULTS When comparing Pkd2/AC6 KO to Pkd2 KO mice, no decrease in liver cyst size was found, and cellular cAMP after [Ca2+]ER depletion only decreased by 12%. Conversely, in PC2-defective cells, inhibition of AC5 significantly reduced cAMP production, pERK1/2 expression and VEGF-A secretion. AC5 inhibitors significantly reduced growth of biliary organoids derived from Pkd2 KO and Pkd2/AC6 KO mice. In vivo treatment with SQ22,536 significantly reduced liver cystic area and cell proliferation in PC2-defective mice. After [Ca2+]ER depletion in PC2-defective cells, STIM1 interacts with AC5 but not with Orai1, the Ca2+ channel that mediates SOCE. CONCLUSION [Ca2+]ER depletion in PC2-defective cells activates AC5 and results in stimulation of cAMP/ERK1-2 signaling, VEGF production and cyst growth. This mechanism may represent a novel therapeutic target. LAY SUMMARY Polycystic liver diseases are characterized by progressive cyst growth until their complications mandate surgery or liver transplantation. In this manuscript, we demonstrate that inhibiting cell proliferation, which is induced by increased levels of cAMP, may represent a novel therapeutic target to slow the progression of the disease.
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Affiliation(s)
- Carlo Spirli
- Section of Digestive Diseases, Yale University, New Haven, Connecticut, USA
| | - Valeria Mariotti
- Section of Digestive Diseases, Yale University, New Haven, Connecticut, USA,Section of Digestive Diseases, International Center for Digestive Health, Department of Medicine and Surgery, University of Milan-Bicocca, Milan, Italy
| | - Ambra Villani
- Section of Digestive Diseases, Yale University, New Haven, Connecticut, USA
| | - Luca Fabris
- Department of Molecular Medicine, University of Padua, Italy
| | - Romina Fiorotto
- Section of Digestive Diseases, Yale University, New Haven, Connecticut, USA
| | - Mario Strazzabosco
- Section of Digestive Diseases, Yale University, New Haven, CT, USA; Section of Digestive Diseases, International Center for Digestive Health, Department of Medicine and Surgery, University of Milan-Bicocca, Milan, Italy.
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21
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Rana N, Conley JM, Soto-Velasquez M, León F, Cutler SJ, Watts VJ, Lill MA. Molecular Modeling Evaluation of the Enantiomers of a Novel Adenylyl Cyclase 2 Inhibitor. J Chem Inf Model 2017; 57:322-334. [PMID: 28068084 DOI: 10.1021/acs.jcim.6b00454] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Adenylyl cyclase 2 (AC2) is one of nine membrane-bound isoforms of adenylyl cyclase that converts ATP into cyclic AMP (cAMP), an important second messenger molecule. Upregulation of AC2 is linked to cancers like pancreatic and small intestinal neuroendocrine tumors (NETs). The structures of the various isoforms of adenylyl cyclases are highly homologous, posing a significant challenge to drug discovery efforts for an effective, isoform-selective modulator of AC2. In a previous study, a screen identified a potential isoform-selective and noncompetitive inhibitor of AC2, SKF83566. In the present study, molecular modeling is used to explore the mode of inhibition of AC2 by SKF83566 and to investigate the active enantiomer of SKF83566. Homology models of hAC2 were built based on canine AC5-C1a and rat AC2-C2a templates. With these models, a combination of flexible docking, molecular dynamics simulations, and free energy calculations using the MM/GBSA methodology suggested an allosteric mechanism in which (S)-SKF83566 binds to an allosteric site near ATP and alters the protein conformation of the ATP binding site, potentially preventing the adenosine moiety of ATP from forming an archlike shape to form cAMP. The predicted binding preference for the (S)-SKF83566 enantiomer and the predicted free energy are consistent with the experimental data.
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Affiliation(s)
- Neha Rana
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University , West Lafayette, Indiana 47907, United States
| | - Jason M Conley
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University , West Lafayette, Indiana 47907, United States
| | - Monica Soto-Velasquez
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University , West Lafayette, Indiana 47907, United States
| | - Francisco León
- Department of BioMolecular Sciences, School of Pharmacy, The University of Mississippi , Oxford, Mississippi 38677, United States
| | - Stephen J Cutler
- Department of BioMolecular Sciences, School of Pharmacy, The University of Mississippi , Oxford, Mississippi 38677, United States
| | - Val J Watts
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University , West Lafayette, Indiana 47907, United States
| | - Markus A Lill
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University , West Lafayette, Indiana 47907, United States
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Montfort WR, Wales JA, Weichsel A. Structure and Activation of Soluble Guanylyl Cyclase, the Nitric Oxide Sensor. Antioxid Redox Signal 2017; 26:107-121. [PMID: 26979942 PMCID: PMC5240008 DOI: 10.1089/ars.2016.6693] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
SIGNIFICANCE Soluble guanylyl/guanylate cyclase (sGC) is the primary receptor for nitric oxide (NO) and is central to the physiology of blood pressure regulation, wound healing, memory formation, and other key physiological activities. sGC is increasingly implicated in disease and is targeted by novel therapeutic compounds. The protein displays a rich evolutionary history and a fascinating signal transduction mechanism, with NO binding to an N-terminal heme-containing domain, which activates the C-terminal cyclase domains. Recent Advances: Crystal structures of individual sGC domains or their bacterial homologues coupled with small-angle x-ray scattering, electron microscopy, chemical cross-linking, and Förster resonance energy transfer measurements are yielding insight into the overall structure for sGC, which is elongated and likely quite dynamic. Transient kinetic measurements reveal a role for individual domains in lowering NO affinity for heme. New sGC stimulatory drugs are now in the clinic and appear to function through binding near or directly to the sGC heme domain, relieving inhibitory contacts with other domains. New sGC-activating drugs show promise for recovering oxidized sGC in diseases with high inflammation by replacing lost heme. CRITICAL ISSUES Despite the many recent advances, sGC regulation, NO activation, and mechanisms of drug binding remain unclear. Here, we describe the molecular evolution of sGC, new molecular models, and the linked equilibria between sGC NO binding, drug binding, and catalytic activity. FUTURE DIRECTIONS Recent results and ongoing studies lay the foundation for a complete understanding of structure and mechanism, and they open the door for new drug discovery targeting sGC. Antioxid. Redox Signal. 26, 107-121.
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Affiliation(s)
- William R Montfort
- Department of Chemistry and Biochemistry, University of Arizona , Tucson, Arizona
| | - Jessica A Wales
- Department of Chemistry and Biochemistry, University of Arizona , Tucson, Arizona
| | - Andrzej Weichsel
- Department of Chemistry and Biochemistry, University of Arizona , Tucson, Arizona
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23
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Bharambe NG, Barathy DV, Syed W, Visweswariah SS, Colaςo M, Misquith S, Suguna K. Substrate specificity determinants of class III nucleotidyl cyclases. FEBS J 2016; 283:3723-3738. [PMID: 27542992 DOI: 10.1111/febs.13837] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 08/08/2016] [Accepted: 08/18/2016] [Indexed: 12/30/2022]
Abstract
The two second messengers in signalling, cyclic AMP and cyclic GMP, are produced by adenylyl and guanylyl cyclases respectively. Recognition and discrimination of the substrates ATP and GTP by the nucleotidyl cyclases are vital in these reactions. Various apo-, substrate- or inhibitor-bound forms of adenylyl cyclase (AC) structures from transmembrane and soluble ACs have revealed the catalytic mechanism of ATP cyclization reaction. Previously reported structures of guanylyl cyclases represent ligand-free forms and inactive open states of the enzymes and thus do not provide information regarding the exact mode of substrate binding. The structures we present here of the cyclase homology domain of a class III AC from Mycobacterium avium (Ma1120) and its mutant in complex with ATP and GTP in the presence of calcium ion, provide the structural basis for substrate selection by the nucleotidyl cyclases at the atomic level. Precise nature of the enzyme-substrate interactions, novel modes of substrate binding and the ability of the binding pocket to accommodate diverse conformations of the substrates have been revealed by the present crystallographic analysis. This is the first report to provide structures of both the nucleotide substrates bound to a nucleotidyl cyclase. DATABASE Coordinates and structure factors have been deposited in the Protein Data Bank with accession numbers: 5D15 (Ma1120CHD +ATP.Ca2+ ), 5D0E (Ma1120CHD +GTP.Ca2+ ), 5D0H (Ma1120CHD (KDA→EGY)+ATP.Ca2+ ), 5D0G (Ma1120CHD (KDA→EGY)+GTP.Ca2+ ). ENZYMES Adenylyl cyclase (EC number: 4.6.1.1).
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Affiliation(s)
- Nikhil G Bharambe
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | | | - Wajeed Syed
- Department of Chemistry, St. Joseph's College, Bangalore, India
| | - Sandhya S Visweswariah
- Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, India
| | - Melwin Colaςo
- Department of Chemistry, St. Joseph's College, Bangalore, India
| | - Sandra Misquith
- Department of Chemistry, St. Joseph's College, Bangalore, India
| | - Kaza Suguna
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India.
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Boularan C, Gales C. Cardiac cAMP: production, hydrolysis, modulation and detection. Front Pharmacol 2015; 6:203. [PMID: 26483685 PMCID: PMC4589651 DOI: 10.3389/fphar.2015.00203] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 09/03/2015] [Indexed: 01/04/2023] Open
Abstract
Cyclic adenosine 3′,5′-monophosphate (cAMP) modulates a broad range of biological processes including the regulation of cardiac myocyte contractile function where it constitutes the main second messenger for β-adrenergic receptors' signaling to fulfill positive chronotropic, inotropic and lusitropic effects. A growing number of studies pinpoint the role of spatial organization of the cAMP signaling as an essential mechanism to regulate cAMP outcomes in cardiac physiology. Here, we will briefly discuss the complexity of cAMP synthesis and degradation in the cardiac context, describe the way to detect it and review the main pharmacological arsenal to modulate its availability.
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Affiliation(s)
- Cédric Boularan
- Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier Toulouse, France
| | - Céline Gales
- Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, U1048, Université Toulouse III Paul Sabatier Toulouse, France
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25
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Barathy DV, Bharambe NG, Syed W, Zaveri A, Visweswariah SS, Colaςo M, Misquith S, Suguna K. Autoinhibitory mechanism and activity-related structural changes in a mycobacterial adenylyl cyclase. J Struct Biol 2015; 190:304-13. [PMID: 25916753 DOI: 10.1016/j.jsb.2015.04.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 04/15/2015] [Accepted: 04/20/2015] [Indexed: 01/02/2023]
Abstract
An adenylyl cyclase from Mycobacterium avium, Ma1120, is a functional orthologue of a pseudogene Rv1120c from Mycobacterium tuberculosis. We report the crystal structure of Ma1120 in a monomeric form and its truncated construct as a dimer. Ma1120 exists as a monomer in solution and crystallized as a monomer in the absence of substrate or inhibitor. An additional α-helix present at the N-terminus of the monomeric structure blocks the active site by interacting with the substrate binding residues and occupying the dimer interface region. However, the enzyme has been found to be active in solution, indicating the movement of the helix away from the interface to facilitate the formation of active dimers in conditions favourable for catalysis. Thus, the N-terminal helix of Ma1120 keeps the enzyme in an autoinhibited state when it is not active. Deletion of this helix enabled us to crystallize the molecule as an active homodimer in the presence of a P-site inhibitor 2',5'-dideoxy-3'-ATP, or pyrophosphate along with metal ions. The substrate specifying lysine residue plays a dual role of interacting with the substrate and stabilizing the dimer. The dimerization loop region harbouring the second substrate specifying residue, an aspartate, shows significant differences in conformation and position between the monomeric and dimeric structures. Thus, this study has not only revealed that significant structural transitions are required for the interconversion of the inactive and the active forms of the enzyme, but also provided precise nature of these transitions.
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Affiliation(s)
| | - Nikhil G Bharambe
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
| | - Wajeed Syed
- Department of Chemistry, St. Joseph's College, Bangalore 560 027, India
| | - Anisha Zaveri
- Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560 012, India
| | - Sandhya S Visweswariah
- Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560 012, India
| | - Melwin Colaςo
- Department of Chemistry, St. Joseph's College, Bangalore 560 027, India
| | - Sandra Misquith
- Department of Chemistry, St. Joseph's College, Bangalore 560 027, India
| | - Kaza Suguna
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India.
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26
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Cooper DMF. Store-operated Ca²⁺-entry and adenylyl cyclase. Cell Calcium 2015; 58:368-75. [PMID: 25978874 DOI: 10.1016/j.ceca.2015.04.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Revised: 04/13/2015] [Accepted: 04/15/2015] [Indexed: 02/06/2023]
Abstract
One of the longest-standing effects of SOCE is in its selective regulation of Ca(2+)-sensitive adenylyl cyclase (AC) activity in non-excitable cells. Remarkably it was this source of Ca(2+) (SOCE) rather than the apparent magnitude of the Ca(2+)-rise that conferred AC responsiveness. The molecular basis for this dependence is now resolved in the case of adenylyl cyclase 8 (AC8). Sensors for Ca(2+) and cAMP targeted to ACs have been particularly useful in dissecting the influences upon and composition of what turn out to be signalling microdomains centred on ACs. A number of physiological processes depend on the regulation by SOCE of ACs, but the issue is under-studied. Here I will expand on these topics and point to some immediate unresolved questions.
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Affiliation(s)
- Dermot M F Cooper
- Department of Pharmacology, University of Cambridge, Cambridge CB2 1PD, United Kingdom.
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27
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Jiang QQ, Sicking W, Ehlers M, Schmuck C. Discovery of potent inhibitors of human β-tryptase from pre-equilibrated dynamic combinatorial libraries. Chem Sci 2014; 6:1792-1800. [PMID: 29163876 PMCID: PMC5644118 DOI: 10.1039/c4sc02943g] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 12/05/2014] [Indexed: 01/07/2023] Open
Abstract
Pre-equilibrated combinatorial libraries based on multivalent peptide acyl hydrazones were used to find potent inhibitors of β-tryptase. The best inhibitors bind to the protein surface, and inhibit β-tryptase with nanomolar affinity (Kica. 10 nM) and high selectivity in a reversible and non-competitive way.
Pre-equilibrated dynamic combinatorial libraries based on acyl hydrazone interchange of peptide-derived hydrazides and di- and tri-aldehydes have been used to discover potent inhibitors with nanomolar affinities for β-tryptase. To identify potent inhibitors the activity of the full library containing 95 members was compared with those of sub-libraries in which individual building blocks were missing. The most active library members contain a rigid central aromatic scaffold with three cationic peptide arms. The arms of the best inhibitors also contained a tailor-made GCP oxoanion binding motif attached to a lysine side chain. The most potent tri-armed hydrazones with peptide arms GKWR or GKWK(GCP) were shown to inhibit β-tryptase (Kica. 10–20 nM) reversibly, non-competitively and selectively (compared to related serine proteases, e.g. trypsin and chymotrypsin), most likely by binding to the protein surface, also in agreement with molecular modelling calculations. These new inhibitors are one order of magnitude more efficient than related tetravalent inhibitors obtained from previous work on a split-mix-combinatorial library and were identified with significantly less effort, demonstrating the usefulness of this approach for the identification of enzyme inhibitors in general.
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Affiliation(s)
- Qian-Qian Jiang
- Institut für Organische Chemie , Universität Duisburg-Essen , Universitätsstraße 7 , 45141 Essen , Germany .
| | - Wilhelm Sicking
- Institut für Organische Chemie , Universität Duisburg-Essen , Universitätsstraße 7 , 45141 Essen , Germany .
| | - Martin Ehlers
- Institut für Organische Chemie , Universität Duisburg-Essen , Universitätsstraße 7 , 45141 Essen , Germany .
| | - Carsten Schmuck
- Institut für Organische Chemie , Universität Duisburg-Essen , Universitätsstraße 7 , 45141 Essen , Germany .
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28
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Steegborn C. Structure, mechanism, and regulation of soluble adenylyl cyclases — similarities and differences to transmembrane adenylyl cyclases. Biochim Biophys Acta Mol Basis Dis 2014; 1842:2535-47. [DOI: 10.1016/j.bbadis.2014.08.012] [Citation(s) in RCA: 142] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 08/19/2014] [Accepted: 08/26/2014] [Indexed: 12/14/2022]
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29
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Triest S, Wohlkönig A, Pardon E, Steyaert J. Production, crystallization and preliminary X-ray diffraction of the Gαs α-helical domain in complex with a nanobody. Acta Crystallogr F Struct Biol Commun 2014; 70:1504-7. [PMID: 25372817 PMCID: PMC4231852 DOI: 10.1107/s2053230x14020962] [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: 08/06/2014] [Accepted: 09/19/2014] [Indexed: 11/10/2022] Open
Abstract
GPCR-G-protein complexes are one of the most important components of cell-signalling cascades. Extracellular signals are sensed by membrane-associated G-protein-coupled receptors (GPCRs) and transduced via G proteins towards intracellular effector molecules. Structural studies of these transient complexes are crucial to understand the molecular details of these interactions. Although a nucleotide-free GPCR-G-protein complex is stable, it is not an ideal sample for crystallization owing to the intrinsic mobility of the Gαs α-helical domain (AHD). To stabilize GPCR-G-protein complexes in a nucleotide-free form, nanobodies were selected that target the flexible GαsAHD. One of these nanobodies, CA9177, was co-crystallized with the GαsAHD. Initial crystals were obtained using the sitting-drop method in a sparse-matrix screen and further optimized. The crystals diffracted to 1.59 Å resolution and belonged to the monoclinic space group P2₁, with unit-cell parameters a=44.07, b=52.55, c=52.66 Å, α=90.00, β=107.89, γ=90.00°. The structure of this specific nanobody reveals its binding epitope on GαsAHD and will help to determine whether this nanobody could be used as crystallization chaperone for GPCR-G-protein complexes.
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Affiliation(s)
- Sarah Triest
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Elsene, Belgium
- Structural Biology Research Center, Vlaams Instituut voor Biotechnology (VIB), Pleinlaan 2, 1050 Elsene, Belgium
| | - Alexandre Wohlkönig
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Elsene, Belgium
- Structural Biology Research Center, Vlaams Instituut voor Biotechnology (VIB), Pleinlaan 2, 1050 Elsene, Belgium
| | - Els Pardon
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Elsene, Belgium
- Structural Biology Research Center, Vlaams Instituut voor Biotechnology (VIB), Pleinlaan 2, 1050 Elsene, Belgium
| | - Jan Steyaert
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Elsene, Belgium
- Structural Biology Research Center, Vlaams Instituut voor Biotechnology (VIB), Pleinlaan 2, 1050 Elsene, Belgium
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30
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Abstract
Recent advances in the AC (adenylate cyclase)/cAMP field reveal overarching roles for the ACs. Whereas few processes are unaffected by cAMP in eukaryotes, ranging from the rapid modulation of ion channel kinetics to the slowest developmental effects, the large number of cellular processes modulated by only three intermediaries, i.e. PKA (protein kinase A), Epacs (exchange proteins directly activated by cAMP) and CNG (cyclic nucleotide-gated) channels, poses the question of how selectivity and fine control is achieved by cAMP. One answer rests on the number of differently regulated and distinctly expressed AC species. Specific ACs are implicated in processes such as insulin secretion, immunological responses, sino-atrial node pulsatility and memory formation, and specific ACs are linked with particular diseased conditions or predispositions, such as cystic fibrosis, Type 2 diabetes and dysrhythmias. However, much of the selectivity and control exerted by cAMP lies in the sophisticated properties of individual ACs, in terms of their coincident responsiveness, dynamic protein scaffolding and organization of cellular microassemblies. The ACs appear to be the centre of highly organized microdomains, where both cAMP and Ca2+, the other major influence on ACs, change in patterns quite discrete from the broad cellular milieu. How these microdomains are organized is beginning to become clear, so that ACs may now be viewed as fundamental signalling centres, whose properties exceed their production of cAMP. In the present review, we summarize how ACs are multiply regulated and the steps that are put in place to ensure discrimination in their signalling. This includes scaffolding of targets and modulators by the ACs and assembling of signalling nexuses in discrete cellular domains. We also stress how these assemblies are cell-specific, context-specific and dynamic, and may be best addressed by targeted biosensors. These perspectives on the organization of ACs uncover new strategies for intervention in systems mediated by cAMP, which promise far more informed specificity than traditional approaches.
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Kleinboelting S, van den Heuvel J, Steegborn C. Structural analysis of human soluble adenylyl cyclase and crystal structures of its nucleotide complexes-implications for cyclase catalysis and evolution. FEBS J 2014; 281:4151-64. [PMID: 25040695 DOI: 10.1111/febs.12913] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 06/29/2014] [Accepted: 07/04/2014] [Indexed: 01/18/2023]
Abstract
UNLABELLED The ubiquitous second messenger cAMP regulates a wide array of functions, from bacterial transcription to mammalian memory. It is synthesized by six evolutionarily distinct adenylyl cyclase (AC) families. In mammals, there are two AC types: nine transmembrane ACs (tmACs) and one soluble AC (sAC). Both AC types belong to the widespread cyclase class III, which has members in numerous organisms from archaeons to mammals. Class III also contains all known guanylyl cyclases (GCs), which synthesize the cAMP-related messenger cGMP in many eukaryotes and possibly some prokaryotes. Among mammalian ACs, sAC is uniquely regulated by bicarbonate, and has been proposed to be more closely related to a bacterial AC subfamily than to mammalian ACs, on the basis of sequence comparisons. Here, we used crystal structures of human sAC catalytic domains to analyze its relationships with other class III ACs and GCs, and to study its substrate selection mechanisms. Structural comparisons revealed a similarity within an sAC-like subfamily but no family-specific structure elements, and an unexpected sAC similarity to eukaryotic GCs and a potential bacterial GC. We further solved novel crystal structures of sAC catalytic domains in complex with a substrate analog, unprocessed ATP substrate, and product after soaking with ATP or GTP. The structures show a novel ATP-binding conformation, and suggest mechanisms for substrate association and recognition. Our results could explain the limited substrate specificity of sAC, suggest how specificity is increased in other cyclases, and indicate evolutionary relationships among class III enzymes, with sAC being close to a putative 'ancestor' cyclase. DATABASE Coordinates and structure factors for the novel sAC-cat structures described have been deposited with the Worldwide PDB (www.pdb.org): ApCpp soak (entry 4usu), ATP + Ca(2+) soak (entry 4usv), GTP + Mg(2+) soak (entry 4ust), ATP soak (entry 4usw).
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32
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Crystal structures of human soluble adenylyl cyclase reveal mechanisms of catalysis and of its activation through bicarbonate. Proc Natl Acad Sci U S A 2014; 111:3727-32. [PMID: 24567411 DOI: 10.1073/pnas.1322778111] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
cAMP is an evolutionary conserved, prototypic second messenger regulating numerous cellular functions. In mammals, cAMP is synthesized by one of 10 homologous adenylyl cyclases (ACs): nine transmembrane enzymes and one soluble AC (sAC). Among these, only sAC is directly activated by bicarbonate (HCO3(-)); it thereby serves as a cellular sensor for HCO3(-), carbon dioxide (CO2), and pH in physiological functions, such as sperm activation, aqueous humor formation, and metabolic regulation. Here, we describe crystal structures of human sAC catalytic domains in the apo state and in complex with substrate analog, products, and regulators. The activator HCO3(-) binds adjacent to Arg176, which acts as a switch that enables formation of the catalytic cation sites. An anionic inhibitor, 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid, inhibits sAC through binding to the active site entrance, which blocks HCO3(-) activation through steric hindrance and trapping of the Arg176 side chain. Finally, product complexes reveal small, local rearrangements that facilitate catalysis. Our results provide a molecular mechanism for sAC catalysis and cellular HCO3(-) sensing and a basis for targeting this system with drugs.
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33
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Dynamics of Gαi1 interaction with type 5 adenylate cyclase reveal the molecular basis for high sensitivity of Gi-mediated inhibition of cAMP production. Biochem J 2013; 454:515-23. [PMID: 23841650 DOI: 10.1042/bj20130554] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Many physiological and pathophysiological processes are regulated by cAMP. Different therapies directly or indirectly influence the cellular concentration of this second messenger. A wide variety of receptors either activates or inhibits adenylate cyclases in order to induce proper physiological responses. A key event in this signalling system is the direct and dynamic interaction of Gαi1 subunits with adenylate cyclases. We established a FRET-based assay between G-protein subunits and AC5 (type 5 adenylate cyclase) and monitored receptor-stimulated interactions between Gαi1 and AC5 in single intact cells with high temporal resolution. We observed that FRET between Gαi1 and AC5 developed at much lower concentration of agonist compared with the overall Gi-protein activity resulting in a left-shift of the concentration-response curve by approximately one order of magnitude. Furthermore, Gi1-protein-mediated attenuation of AC5-dependent increases in cAMP occurred at comparable low concentrations of agonist. On analysing the dynamics we found the dissociation of the Gαi1 subunits and AC5 to occur significantly slower than the G-protein deactivation and to be insensitive to RGS4 (regulator of G-protein signalling type 4) expression. This led us to the conclusion that AC5, by binding active Gαi1, interferes with G-protein deactivation and reassembly and thereby might sensitize its own regulation.
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34
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Brand CS, Hocker HJ, Gorfe AA, Cavasotto CN, Dessauer CW. Isoform selectivity of adenylyl cyclase inhibitors: characterization of known and novel compounds. J Pharmacol Exp Ther 2013; 347:265-75. [PMID: 24006339 DOI: 10.1124/jpet.113.208157] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Nine membrane-bound adenylyl cyclase (AC) isoforms catalyze the production of the second messenger cyclic AMP (cAMP) in response to various stimuli. Reduction of AC activity has well documented benefits, including benefits for heart disease and pain. These roles have inspired development of isoform-selective AC inhibitors, a lack of which currently limits exploration of functions and/or treatment of dysfunctions involving AC/cAMP signaling. However, inhibitors described as AC5- or AC1-selective have not been screened against the full panel of AC isoforms. We have measured pharmacological inhibitor profiles for all transmembrane AC isoforms. We found that 9-(tetrahydro-2-furanyl)-9H-purin-6-amine (SQ22,536), 2-amino-7-(furanyl)-7,8-dihydro-5(6H)-quinazolinone (NKY80), and adenine 9-β-d-arabinofuranoside (Ara-A), described as supposedly AC5-selective, do not discriminate between AC5 and AC6, whereas the putative AC1-selective inhibitor 5-[[2-(6-amino-9H-purin-9-yl)ethyl]amino]-1-pentanol (NB001) does not directly target AC1 to reduce cAMP levels. A structure-based virtual screen targeting the ATP binding site of AC was used to identify novel chemical structures that show some preference for AC1 or AC2. Mutation of the AC2 forskolin binding pocket does not interfere with inhibition by SQ22,536 or the novel AC2 inhibitor, suggesting binding to the catalytic site. Thus, we show that compounds lacking the adenine chemical signature and targeting the ATP binding site can potentially be used to develop AC isoform-specific inhibitors, and discuss the need to reinterpret literature using AC5/6-selective molecules SQ22,536, NKY80, and Ara-A.
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Affiliation(s)
- Cameron S Brand
- Department of Integrative Biology and Pharmacology (C.S.B., H.J.H., A.A.G., C.W.D.), and School of Biomedical Informatics (C.N.C.), University of Texas Health Science Center, Houston, Texas; and Instituto de Investigación en Biomedicina de Buenos Aires-CONICET-Partner Institute of the Max Planck Society, Buenos Aires, Argentina (C.N.C.)
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35
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Nordemann U, Wifling D, Schnell D, Bernhardt G, Stark H, Seifert R, Buschauer A. Luciferase reporter gene assay on human, murine and rat histamine H4 receptor orthologs: correlations and discrepancies between distal and proximal readouts. PLoS One 2013; 8:e73961. [PMID: 24023919 PMCID: PMC3759464 DOI: 10.1371/journal.pone.0073961] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 07/24/2013] [Indexed: 11/18/2022] Open
Abstract
The investigation of the (patho)physiological role of the histamine H4 receptor (H4R) and its validation as a possible drug target in translational animal models are compromised by distinct species-dependent discrepancies regarding potencies and receptor subtype selectivities of the pharmacological tools. Such differences were extremely pronounced in case of proximal readouts, e. g. [(32)P]GTPase or [(35)S]GTPγS binding assays. To improve the predictability of in vitro investigations, the aim of this study was to establish a reporter gene assay for human, murine and rat H4Rs, using bioluminescence as a more distal readout. For this purpose a cAMP responsive element (CRE) controlled luciferase reporter gene assay was established in HEK293T cells, stably expressing the human (h), the mouse (m) or the rat (r) H4R. The potencies and efficacies of 23 selected ligands (agonists, inverse agonists and antagonists) were determined and compared with the results obtained from proximal readouts. The potencies of the examined ligands at the human H4R were consistent with reported data from [(32)P]GTPase or [(35)S]GTPγS binding assays, despite a tendency toward increased intrinsic efficacies of partial agonists. The differences in potencies of individual agonists at the three H4R orthologs were generally less pronounced compared to more proximal readouts. In conclusion, the established reporter gene assay is highly sensitive and reliable. Regarding discrepancies compared to data from functional assays such as [(32)P]GTPase and [(35)S]GTPγS binding, the readout may reflect multifactorial causes downstream from G-protein activation, e.g. activation/amplification of or cross-talk between different signaling pathways.
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Affiliation(s)
- Uwe Nordemann
- Institute of Pharmacy, University of Regensburg, Regensburg, Germany
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36
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Follmann M, Griebenow N, Hahn MG, Hartung I, Mais FJ, Mittendorf J, Schäfer M, Schirok H, Stasch JP, Stoll F, Straub A. The chemistry and biology of soluble guanylate cyclase stimulators and activators. Angew Chem Int Ed Engl 2013; 52:9442-62. [PMID: 23963798 DOI: 10.1002/anie.201302588] [Citation(s) in RCA: 153] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Indexed: 12/14/2022]
Abstract
The vasodilatory properties of nitric oxide (NO) have been utilized in pharmacotherapy for more than 130 years. Still today, NO-donor drugs are important in the management of cardiovascular diseases. However, inhaled NO or drugs releasing NO and organic nitrates are associated with noteworthy therapeutic shortcomings, including resistance to NO in some disease states, the development of tolerance during long-term treatment, and nonspecific effects, such as post-translational modification of proteins. The beneficial actions of NO are mediated by stimulation of soluble guanylate cyclase (sGC), a heme-containing enzyme which produces the intracellular signaling molecule cyclic guanosine monophosphate (cGMP). Recently, two classes of compounds have been discovered that amplify the function of sGC in a NO-independent manner, the so-called sGC stimulators and sGC activators. The most advanced drug, the sGC stimulator riociguat, has successfully undergone Phase III clinical trials for different forms of pulmonary hypertension.
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Affiliation(s)
- Markus Follmann
- Bayer Pharma Aktiengesellschaft, Global Drug Discovery, Aprather Weg 18a, 42113 Wuppertal, Germany.
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37
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Follmann M, Griebenow N, Hahn MG, Hartung I, Mais FJ, Mittendorf J, Schäfer M, Schirok H, Stasch JP, Stoll F, Straub A. Chemie und Biologie der Stimulatoren und Aktivatoren der löslichen Guanylatcyclase. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201302588] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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38
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Osawa T, Inanaga H, Numata T. Crystal structure of the Cmr2-Cmr3 subcomplex in the CRISPR-Cas RNA silencing effector complex. J Mol Biol 2013; 425:3811-23. [PMID: 23583914 DOI: 10.1016/j.jmb.2013.03.042] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 02/26/2013] [Accepted: 03/30/2013] [Indexed: 12/26/2022]
Abstract
Clustered, regularly interspaced, short palindromic repeat (CRISPR) loci found in prokaryotes are transcribed to produce CRISPR RNAs (crRNAs) that, together with CRISPR-associated (Cas) proteins, target and degrade invading genetic materials. Cmr proteins (Cmr1-6) and crRNA form a sequence-specific RNA silencing effector complex. Here, we report the crystal structures of the Pyrococcus furiosus Cmr2-Cmr3 subcomplex bound with nucleotides (3'-AMP or ATP). The association of Cmr2 and Cmr3 forms an idiosyncratic crevasse, which binds the nucleotides. Cmr3 shares structural similarity with Cas6, which cleaves precursor crRNA for maturation, suggesting the divergent evolution of these proteins. Due to the structural resemblance, the properties of the RNA binding surface observed in Cas6 are well conserved in Cmr3, indicating the RNA binding ability of Cmr3. This surface of Cmr3 constitutes the crevasse observed in the Cmr2-Cmr3 complex. Our findings suggest that the Cmr2-Cmr3 complex uses the crevasse to bind crRNA and/or substrate RNA during the reaction.
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Affiliation(s)
- Takuo Osawa
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba-shi, Ibaraki 305-8566, Japan
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39
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Mones L, Tang WJ, Florián J. Empirical valence bond simulations of the chemical mechanism of ATP to cAMP conversion by anthrax edema factor. Biochemistry 2013; 52:2672-82. [PMID: 23480863 DOI: 10.1021/bi400088y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The two-metal catalysis by the adenylyl cyclase domain of the anthrax edema factor toxin was simulated using the empirical valence bond (EVB) quantum mechanical/molecular mechanical approach. These calculations considered the energetics of the nucleophile deprotonation and the formation of a new P-O bond in aqueous solution and in the enzyme-substrate complex present in the crystal structure models of the reactant and product states of the reaction. Our calculations support a reaction pathway that involves metal-assisted transfer of a proton from the nucleophile to the bulk aqueous solution followed by subsequent formation of an unstable pentavalent intermediate that decomposes into cAMP and pyrophosphate (PPi). This pathway involves ligand exchange in the first solvation sphere of the catalytic metal. At 12.9 kcal/mol, the barrier for the last step of the reaction, the cleavage of the P-O bond to PPi, corresponds to the highest point on the free energy profile for this reaction pathway. However, this energy is too close to the value of 11.4 kcal/mol calculated for the barrier of the nucleophilic attack step to reach a definitive conclusion about the rate-limiting step. The calculated reaction mechanism is supported by reasonable agreement between the experimental and calculated catalytic rate constant decrease caused by the mutation of the active site lysine 346 to arginine.
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Affiliation(s)
- Letif Mones
- Department of Chemistry, Loyola University Chicago, Chicago, Illinois 60660, USA
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40
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Allerston CK, von Delft F, Gileadi O. Crystal structures of the catalytic domain of human soluble guanylate cyclase. PLoS One 2013; 8:e57644. [PMID: 23505436 PMCID: PMC3591389 DOI: 10.1371/journal.pone.0057644] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 01/22/2013] [Indexed: 01/05/2023] Open
Abstract
Soluble guanylate cyclase (sGC) catalyses the synthesis of cyclic GMP in response to nitric oxide. The enzyme is a heterodimer of homologous α and β subunits, each of which is composed of multiple domains. We present here crystal structures of a heterodimer of the catalytic domains of the α and β subunits, as well as an inactive homodimer of β subunits. This first structure of a metazoan, heteromeric cyclase provides several observations. First, the structures resemble known structures of adenylate cyclases and other guanylate cyclases in overall fold and in the arrangement of conserved active-site residues, which are contributed by both subunits at the interface. Second, the subunit interaction surface is promiscuous, allowing both homodimeric and heteromeric association; the preference of the full-length enzyme for heterodimer formation must derive from the combined contribution of other interaction interfaces. Third, the heterodimeric structure is in an inactive conformation, but can be superposed onto an active conformation of adenylate cyclase by a structural transition involving a 26° rigid-body rotation of the α subunit. In the modelled active conformation, most active site residues in the subunit interface are precisely aligned with those of adenylate cyclase. Finally, the modelled active conformation also reveals a cavity related to the active site by pseudo-symmetry. The pseudosymmetric site lacks key active site residues, but may bind allosteric regulators in a manner analogous to the binding of forskolin to adenylate cyclase. This indicates the possibility of developing a new class of small-molecule modulators of guanylate cyclase activity targeting the catalytic domain.
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Affiliation(s)
- Charles K. Allerston
- Structural Genomics Consortium, University of Oxford, Oxford, The United Kingdom
| | - Frank von Delft
- Structural Genomics Consortium, University of Oxford, Oxford, The United Kingdom
| | - Opher Gileadi
- Structural Genomics Consortium, University of Oxford, Oxford, The United Kingdom
- * E-mail:
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Jiang QQ, Bartsch L, Sicking W, Wich PR, Heider D, Hoffmann D, Schmuck C. A new approach to inhibit human β-tryptase by protein surface binding of four-armed peptide ligands with two different sets of arms. Org Biomol Chem 2013; 11:1631-9. [DOI: 10.1039/c3ob27302d] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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42
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Makino R, Yazawa S, Hori H, Shiro Y. Interactions of soluble guanylate cyclase with a P-site inhibitor: effects of gaseous heme ligands, azide, and allosteric activators on the binding of 2'-deoxy-3'-GMP. Biochemistry 2012; 51:9277-89. [PMID: 23106307 DOI: 10.1021/bi3004044] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Nitric oxide (NO) elicits a wide variety of physiological responses by binding to the heme in soluble guanylate cyclase (sGC) to stimulate cGMP production. Although nucleotides, such as ATP or GTP analogues, have been reported to regulate the signaling of NO binding from the heme site to the catalytic site, the other regulatory functions of nucleotides remain unexamined. Among the nucleotides tested, we found that 2'-d-3'-GMP acted as a potent noncompetitive inhibitor with respect to Mn-GTP, when the ferrous enzyme combined with NO, CO, or allosteric activator BAY 41-2272. 2'-d-3'-GMP also displayed nearly identical patterns of inhibition for the ferric enzyme, in which the binding of N(3)(-) or BAY 41-2272 significantly increased the inhibitory effects of the nucleotide. Equilibrium dialysis measurements using the CO-ligated enzyme in the presence of allosteric activators demonstrated that 2'-d-3'-GMP exclusively binds to the catalytic site of sGC. Furthermore, the affinity of 2'-d-3'-GMP for the enzyme was found to increase upon addition of foscarnet, an analogue of PP(i). These findings together with other kinetic results imply that 2'-d-3'-GMP acts as a P-site inhibitor probably by forming a dead-end complex, sGC-2'-d-3'-GMP-PP(i), in the catalytic reaction. The formation of the complex of the enzyme with 2'-d-3'-GMP does not seem to be associated with changes in the Fe-proximal His bond strength, because the CO coordination state or the redox potentials of the enzyme-heme complex are virtually unaffected.
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Affiliation(s)
- Ryu Makino
- Department of Life Science, College of Science, Rikkyo University, Nishi-ikebukuro 3-34-1, Toshima-ku, Tokyo 171-8501, Japan.
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Cook ZC, Gray MA, Cann MJ. Elevated carbon dioxide blunts mammalian cAMP signaling dependent on inositol 1,4,5-triphosphate receptor-mediated Ca2+ release. J Biol Chem 2012; 287:26291-301. [PMID: 22654111 PMCID: PMC3406713 DOI: 10.1074/jbc.m112.349191] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Revised: 05/15/2012] [Indexed: 12/11/2022] Open
Abstract
Elevated CO(2) is generally detrimental to animal cells, suggesting an interaction with core processes in cell biology. We demonstrate that elevated CO(2) blunts G protein-activated cAMP signaling. The effect of CO(2) is independent of changes in intracellular and extracellular pH, independent of the mechanism used to activate the cAMP signaling pathway, and is independent of cell context. A combination of pharmacological and genetic tools demonstrated that the effect of elevated CO(2) on cAMP levels required the activity of the IP(3) receptor. Consistent with these findings, CO(2) caused an increase in steady state cytoplasmic Ca(2+) concentrations not observed in the absence of the IP(3) receptor or under nonspecific acidotic conditions. We examined the well characterized cAMP-dependent inhibition of the isoform 3 Na(+)/H(+) antiporter (NHE3) to demonstrate a functional relevance for CO(2)-mediated reductions in cellular cAMP. Consistent with the cellular biochemistry, elevated CO(2) abrogated the inhibitory effect of cAMP on NHE3 function via an IP(3) receptor-dependent mechanism.
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Affiliation(s)
- Zara C. Cook
- From the School of Biological and Biomedical Sciences and
- Biophysical Sciences Institute, Durham University, South Road, Durham DH1 3LE, United Kingdom and
| | - Michael A. Gray
- Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, United Kingdom
| | - Martin J. Cann
- From the School of Biological and Biomedical Sciences and
- Biophysical Sciences Institute, Durham University, South Road, Durham DH1 3LE, United Kingdom and
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44
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Cocozaki AI, Ramia NF, Shao Y, Hale CR, Terns RM, Terns MP, Li H. Structure of the Cmr2 subunit of the CRISPR-Cas RNA silencing complex. Structure 2012; 20:545-53. [PMID: 22405013 DOI: 10.1016/j.str.2012.01.018] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Revised: 01/10/2012] [Accepted: 01/15/2012] [Indexed: 12/26/2022]
Abstract
Cmr2 is the largest and an essential subunit of a CRISPR RNA-Cas protein complex (the Cmr complex) that cleaves foreign RNA to protect prokaryotes from invading genetic elements. Cmr2 is thought to be the catalytic subunit of the effector complex because of its N-terminal HD nuclease domain. Here, however, we report that the HD domain of Cmr2 is not required for cleavage by the complex in vitro. The 2.3Å crystal structure of Pyrococcus furiosus Cmr2 (lacking the HD domain) reveals two adenylyl cyclase-like and two α-helical domains. The adenylyl cyclase-like domains are arranged as in homodimeric adenylyl cyclases and bind ADP and divalent metals. However, mutagenesis studies show that the metal- and ADP-coordinating residues of Cmr2 are also not critical for cleavage by the complex. Our findings suggest that another component provides the catalytic function and that the essential role by Cmr2 does not require the identified ADP- or metal-binding or HD domains in vitro.
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Affiliation(s)
- Alexis I Cocozaki
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306, USA
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45
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Topal H, Fulcher NB, Bitterman J, Salazar E, Buck J, Levin LR, Cann MJ, Wolfgang MC, Steegborn C. Crystal structure and regulation mechanisms of the CyaB adenylyl cyclase from the human pathogen Pseudomonas aeruginosa. J Mol Biol 2011; 416:271-86. [PMID: 22226839 DOI: 10.1016/j.jmb.2011.12.045] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 12/18/2011] [Accepted: 12/21/2011] [Indexed: 12/15/2022]
Abstract
Pseudomonas aeruginosa is an opportunistic bacterial pathogen and a major cause of healthcare-associated infections. While the organism's intrinsic and acquired resistance to most antibiotics hinders treatment of P. aeruginosa infections, the regulatory networks controlling its virulence provide novel targets for drug development. CyaB, a key regulator of P. aeruginosa virulence, belongs to the Class III adenylyl cyclase (AC) family of enzymes that synthesize the second messenger cyclic adenosine 3',5'-monophosphate. These enzymes consist of a conserved catalytic domain fused to one or more regulatory domains. We describe here the biochemical and structural characterization of CyaB and its inhibition by small molecules. We show that CyaB belongs to the Class IIIb subfamily, and like other subfamily members, its activity is stimulated by inorganic carbon. CyaB is also regulated by its N-terminal MASE2 (membrane-associated sensor 2) domain, which acts as a membrane anchor. Using a genetic screen, we identified activating mutations in CyaB. By solving the crystal structure of the CyaB catalytic domain, we rationalized the effects of these mutations and propose that CyaB employs regulatory mechanisms similar to other Class III ACs. The CyaB structure further indicates subtle differences compared to other Class III ACs in both the active site and the inhibitor binding pocket. Consistent with these differences, we observed a unique inhibition profile, including identification of a CyaB selective compound. Overall, our results reveal mechanistic details of the physiological and pharmacological regulation of CyaB and provide the basis for its exploitation as a therapeutic drug target.
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Affiliation(s)
- Hüsnü Topal
- Department of Physiological Chemistry, Ruhr-University Bochum, 44801 Bochum, Germany
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Yan X, Gao S, Tang M, Xi J, Gao L, Zhu M, Luo H, Hu X, Zheng Y, Hescheler J, Liang H. Adenylyl cyclase/cAMP-PKA-mediated phosphorylation of basal L-type Ca(2+) channels in mouse embryonic ventricular myocytes. Cell Calcium 2011; 50:433-43. [PMID: 21824653 DOI: 10.1016/j.ceca.2011.07.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Revised: 06/16/2011] [Accepted: 07/12/2011] [Indexed: 10/17/2022]
Abstract
In fetal mammalian heart, constitutive adenylyl cyclase/cyclic AMP-dependent protein kinase A (cAMP-PKA)-mediated phosphorylation, independent of β-adrenergic receptor stimulation, could under such circumstances play an important role in sustaining the L-type calcium channel current (I(Ca,L)) and regulating other PKA dependent phosphorylation targets. In this study, we investigated the regulation of L-type Ca(2+) channel (LTCC) in murine embryonic ventricles. The data indicated a higher phosphorylation state of LTCC at early developmental stage (EDS, E9.5-E11.5) than late developmental stage (LDS, E16.5-E18.5). An intrinsic adenylyl cyclase (AC) activity, PKA activity and basal cAMP concentration were obviously higher at EDS than LDS. The cAMP increase in the presence of isobutylmethylxanthine (IBMX, nonselective phosphodiesterase inhibitor) was further augmented at LDS but not at EDS by chelation of intracellular Ca(2+) with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA)-acetoxymethyl ester (BAPTA-AM). Furthermore, I(Ca,L) increased with time after patch rupture in LDS cardiomyocytes dialyzed with pipette solution containing BAPTA whereas not at EDS. Thus we conclude that the high basal level of LTCC phosphorylation is due to the high intrinsic PKA activity and the high intrinsic AC activity at EDS. The latter is possibly owing to the little or no effect of Ca(2+) influx via LTCCs on AC activity, leading to the inability to inhibit AC.
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Affiliation(s)
- Xisheng Yan
- Department of Physiology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
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47
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Erdorf M, Mou TC, Seifert R. Impact of divalent metal ions on regulation of adenylyl cyclase isoforms by forskolin analogs. Biochem Pharmacol 2011; 82:1673-81. [PMID: 21843517 DOI: 10.1016/j.bcp.2011.07.099] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 07/27/2011] [Accepted: 07/29/2011] [Indexed: 01/20/2023]
Abstract
Mammalian membranous adenylyl cyclases (mACs) play an important role in transmembrane signalling events in almost every cell and represent an interesting drug target. Forskolin (FS) is an invaluable research tool, activating AC isoforms 1-8. However, there is a paucity of AC isoform-selective FS analogs. Therefore, we examined the effects of FS and six FS derivatives on recombinant ACs 1, 2 and 5, representing members of different mAC families. Correlations of the pharmacological properties of the different AC isoforms revealed pronounced differences between ACs 1, 2 and 5. Additionally, potencies and efficacies of FS derivatives changed for any given AC isoform, depending on the metal ion, Mg(2+) or Mn(2+). The most striking effects of Mg(2+) and Mn(2+) on the diterpene profile were observed for AC2 where the large inhibitory effect of BODIPY-FS in the presence of Mg(2+) was considerably reduced in the presence of Mn(2+). Sequence alignment and docking experiments confirmed an exceptional position of AC2 compared to ACs 1 and 5 with respect to the structural environment of the catalytic core and cation-dependent diterpene effects. In conclusion, mAC isoforms 1, 2 and 5 exhibit a distinct pharmacological diterpene profile, depending on the divalent cation present. mAC crystal structures and modelling/docking studies provided an explanation for the pharmacological differences between the AC isoforms. Our study constitutes an important step towards the development of isoform-specific diterpenes exhibiting stimulatory or inhibitory effects.
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Affiliation(s)
- Miriam Erdorf
- Department of Pharmacology and Toxicology, University of Regensburg, Germany
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Trinitrophenyl derivatives bind differently from parent adenine nucleotides to Ca2+-ATPase in the absence of Ca2+. Proc Natl Acad Sci U S A 2011; 108:1833-8. [PMID: 21239683 DOI: 10.1073/pnas.1017659108] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Trinitrophenyl derivatives of adenine nucleotides are widely used for probing ATP-binding sites. Here we describe crystal structures of Ca(2+)-ATPase, a representative P-type ATPase, in the absence of Ca(2+) with bound ATP, trinitrophenyl-ATP, -ADP, and -AMP at better than 2.4-Å resolution, stabilized with thapsigargin, a potent inhibitor. These crystal structures show that the binding mode of the trinitrophenyl derivatives is distinctly different from the parent adenine nucleotides. The adenine binding pocket in the nucleotide binding domain of Ca(2+)-ATPase is now occupied by the trinitrophenyl group, and the side chains of two arginines sandwich the adenine ring, accounting for the much higher affinities of the trinitrophenyl derivatives. Trinitrophenyl nucleotides exhibit a pronounced fluorescence in the E2P ground state but not in the other E2 states. Crystal structures of the E2P and E2 ∼ P analogues of Ca(2+)-ATPase with bound trinitrophenyl-AMP show that different arrangements of the three cytoplasmic domains alter the orientation and water accessibility of the trinitrophenyl group, explaining the origin of "superfluorescence." Thus, the crystal structures demonstrate that ATP and its derivatives are highly adaptable to a wide range of site topologies stabilized by a variety of interactions.
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Active-Site Structure of Class IV Adenylyl Cyclase and Transphyletic Mechanism. J Mol Biol 2011; 405:787-803. [DOI: 10.1016/j.jmb.2010.11.026] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Revised: 11/03/2010] [Accepted: 11/09/2010] [Indexed: 01/18/2023]
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50
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Abstract
Interplay between the signaling pathways of the intracellular second messengers, cAMP and Ca(2+), has vital consequences for numerous essential physiological processes. Although cAMP can impact on Ca(2+)-homeostasis at many levels, Ca(2+) either directly, or indirectly (via calmodulin [CaM], CaM-binding proteins, protein kinase C [PKC] or Gβγ subunits) may also regulate cAMP synthesis. Here, we have evaluated the evidence for regulation of adenylyl cyclases (ACs) by Ca(2+)-signaling pathways, with an emphasis on verification of this regulation in a physiological context. The effects of compartmentalization and protein signaling complexes on the regulation of AC activity by Ca(2+)-signaling pathways are also addressed. Major gaps are apparent in the interactions that have been assumed, revealing a need to comprehensively clarify the effects of Ca(2+) signaling on individual ACs, so that the important ramifications of this critical interplay between Ca(2+) and cAMP are fully appreciated.
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Affiliation(s)
- Michelle L Halls
- Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD, United Kingdom
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