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Knight KM, Obarow EG, Wei W, Mani S, Esteller MI, Cui M, Ma N, Martin SA, Brinson E, Hewitt N, Soden GM, Logothetis DE, Vaidehi N, Dohlman HG. Molecular annotation of G protein variants in a neurological disorder. Cell Rep 2023; 42:113462. [PMID: 37980565 PMCID: PMC10872635 DOI: 10.1016/j.celrep.2023.113462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 10/04/2023] [Accepted: 11/02/2023] [Indexed: 11/21/2023] Open
Abstract
Heterotrimeric G proteins transduce extracellular chemical messages to generate appropriate intracellular responses. Point mutations in GNAO1, encoding the G protein αo subunit, have been implicated in a pathogenic condition characterized by seizures, movement disorders, intellectual disability, and developmental delay (GNAO1 disorder). However, the effects of these mutations on G protein structure and function are unclear. Here, we report the effects of 55 mutations on Gαo conformation, thermostability, nucleotide binding, and hydrolysis, as well as interaction with Gβγ subunits, receptors, and effectors. Our effort reveals four functionally distinct groups of mutants, including one group that sequesters receptors and another that sequesters Gβγ, both acting in a genetically dominant manner. These findings provide a more comprehensive understanding of disease-relevant mutations and reveal that GNAO1 disorder is likely composed of multiple mechanistically distinct disorders that will likely require multiple therapeutic strategies.
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Affiliation(s)
- Kevin M Knight
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Elizabeth G Obarow
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Wenyuan Wei
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
| | - Sepehr Mani
- Department of Pharmaceutical Sciences, Northeastern University, Boston, MA 02115, USA
| | - Maria I Esteller
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Meng Cui
- Department of Pharmaceutical Sciences, Northeastern University, Boston, MA 02115, USA
| | - Ning Ma
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
| | - Sarah A Martin
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Emily Brinson
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Natalie Hewitt
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Gaby M Soden
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Diomedes E Logothetis
- Department of Pharmaceutical Sciences, Northeastern University, Boston, MA 02115, USA.
| | - Nagarajan Vaidehi
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA.
| | - Henrik G Dohlman
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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Suitability of Roselle-Hibiscus sabdariffa L. as Raw Material for Soft Drink Production. J FOOD QUALITY 2020. [DOI: 10.1155/2020/8864142] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Consumption of conventional soft drinks has been linked with several diseases in man. This has called for the consumption of natural soft drinks such as roselle drink. Roselle-Hibiscus sabdariffa L. is the major raw material for the production of beverage called cranberry (Florida), bissap (Egypt), zobo (Nigeria), and roselle drink generally. The nutritional and phytochemical properties found in roselle make the plant useful in the preparation of some drugs and food. It has been reported that consumption of roselle drink helps to cure diseases such as high blood pressure and diabetes. The pharmacological properties of the plant are traceable to activities of flavonoid and anthocyanin which are the major antioxidants in roselle. Good aroma and colour of the drink are among the characteristics displayed by the plant. However, consumers are sometimes exposed to risks when the drink is consumed after 24 hours of preparation due to the proliferation of spoilage microorganisms in the drink. Most of these microbes thrive even at extreme temperatures. Unfortunately, some of these microorganisms are of public health importance causing diseases such as meningitis and dysentery. Researchers have revealed that roselle calyx is the major source of contamination in the drink. This paper reviews the suitability of the plant for soft drink production. It further highlights the nutrition, pharmacology, and limitations of the plant for soft drink production.
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Cevheroğlu O, Becker JM, Son ÇD. GPCR-Gα protein precoupling: Interaction between Ste2p, a yeast GPCR, and Gpa1p, its Gα protein, is formed before ligand binding via the Ste2p C-terminal domain and the Gpa1p N-terminal domain. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:2435-2446. [PMID: 28958779 DOI: 10.1016/j.bbamem.2017.09.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 09/20/2017] [Accepted: 09/22/2017] [Indexed: 01/19/2023]
Abstract
G protein coupled receptors bind ligands that initiate intracellular signaling cascades via heterotrimeric G proteins. In this study, involvement of the N-terminal residues of yeast G-alpha (Gpa1p) with the C-terminal residues of a full-length or C-terminally truncated Ste2p were investigated using bioluminescence resonance energy transfer (BRET), a non-radiative energy transfer phenomenon where protein-protein interactions can be quantified between a donor bioluminescent molecule and a suitable acceptor fluorophore. Constitutive and position-dependent BRET signal was observed in the absence of agonist (α-factor). Upon the activation of the receptors with α-factor, no significant change in BRET signal was observed. The location of Ste2p-Gpa1p heterodimer was investigated using confocal fluorescence microscopy and bimolecular fluorescence complementation (BiFC) assay, a technique where two non-fluorescent fragments of a fluorescent protein reassemble in vivo to restore fluorescence property thereby directly reporting a protein-protein interaction. BiFC experiments resulted in a dimerization signal intracellularly during biosynthesis on the endoplasmic reticulum (ER) and on the plasma membrane (PM). The constitutive BRET and BiFC signals observed on ER between Ste2p and Gpa1p in their quiescent and activated states are indicative of pre-coupling between these two proteins. This study is the first to show that the extreme N-terminus of yeast G protein alpha subunit is in close proximity to its receptor. The data suggests a pre-coupled heterodimer prior to receptor activation. The images presented in this study are the first direct in vivo evidence showing the localization of receptor - G protein heterodimers during biosynthesis and before reaching the plasma membrane.
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Affiliation(s)
- Orkun Cevheroğlu
- Department of Microbiology, University of Tennessee, Knoxville, TN 37996-0845, United States; Department of Biological Sciences, Middle East Technical University, Universiteler Mah. Dumlupinar Blv. No: 1, Çankaya, Ankara, 06800, Turkey
| | - Jeffrey M Becker
- Department of Microbiology, University of Tennessee, Knoxville, TN 37996-0845, United States
| | - Çağdaş D Son
- Department of Biological Sciences, Middle East Technical University, Universiteler Mah. Dumlupinar Blv. No: 1, Çankaya, Ankara, 06800, Turkey.
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4
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de Opakua AI, Parag-Sharma K, DiGiacomo V, Merino N, Leyme A, Marivin A, Villate M, Nguyen LT, de la Cruz-Morcillo MA, Blanco-Canosa JB, Ramachandran S, Baillie GS, Cerione RA, Blanco FJ, Garcia-Marcos M. Molecular mechanism of Gαi activation by non-GPCR proteins with a Gα-Binding and Activating motif. Nat Commun 2017; 8:15163. [PMID: 28516903 PMCID: PMC5454376 DOI: 10.1038/ncomms15163] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 03/06/2017] [Indexed: 01/03/2023] Open
Abstract
Heterotrimeric G proteins are quintessential signalling switches activated by nucleotide exchange on Gα. Although activation is predominantly carried out by G-protein-coupled receptors (GPCRs), non-receptor guanine-nucleotide exchange factors (GEFs) have emerged as critical signalling molecules and therapeutic targets. Here we characterize the molecular mechanism of G-protein activation by a family of non-receptor GEFs containing a Gα-binding and -activating (GBA) motif. We combine NMR spectroscopy, computational modelling and biochemistry to map changes in Gα caused by binding of GBA proteins with residue-level resolution. We find that the GBA motif binds to the SwitchII/α3 cleft of Gα and induces changes in the G-1/P-loop and G-2 boxes (involved in phosphate binding), but not in the G-4/G-5 boxes (guanine binding). Our findings reveal that G-protein-binding and activation mechanisms are fundamentally different between GBA proteins and GPCRs, and that GEF-mediated perturbation of nucleotide phosphate binding is sufficient for Gα activation. Nonreceptor guanine-nucleotide exchange factors (GEFs) are emerging as important regulators of heterotrimeric G proteins. Here, the authors present structural and mechanistic insights into how a class of nonreceptor GEFs containing the Ga-Binding and Activating motif interact and modulate G proteins.
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Affiliation(s)
| | - Kshitij Parag-Sharma
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118, USA
| | - Vincent DiGiacomo
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118, USA
| | | | - Anthony Leyme
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118, USA
| | - Arthur Marivin
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118, USA
| | | | - Lien T Nguyen
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118, USA
| | | | - Juan B Blanco-Canosa
- Department of Chemistry and Molecular Pharmacology, IRB Barcelona, 08028 Barcelona, Spain
| | - Sekar Ramachandran
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA
| | - George S Baillie
- Institute of Cardiovascular and Medical Sciences, Department of Molecular Pharmacology, University of Glasgow, Glasgow G12 8QQ, UK
| | - Richard A Cerione
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA.,Department of Molecular Medicine, Cornell University, Ithaca, New York 14853, USA
| | - Francisco J Blanco
- CIC bioGUNE, 48160 Derio, Spain.,IKERBASQUE, Basque Foundation for Science, 48160 Bilbao, Spain
| | - Mikel Garcia-Marcos
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118, USA
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Bondar A, Lazar J. The G protein G i1 exhibits basal coupling but not preassembly with G protein-coupled receptors. J Biol Chem 2017; 292:9690-9698. [PMID: 28438833 DOI: 10.1074/jbc.m116.768127] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 04/21/2017] [Indexed: 11/06/2022] Open
Abstract
The Gi/o protein family transduces signals from a diverse group of G protein-coupled receptors (GPCRs). The observed specificity of Gi/o-GPCR coupling and the high rate of Gi/o signal transduction have been hypothesized to be enabled by the existence of stable associates between Gi/o proteins and their cognate GPCRs in the inactive state (Gi/o-GPCR preassembly). To test this hypothesis, we applied the recently developed technique of two-photon polarization microscopy (2PPM) to Gαi1 subunits labeled with fluorescent proteins and four GPCRs: the α2A-adrenergic receptor, GABAB, cannabinoid receptor type 1 (CB1R), and dopamine receptor type 2. Our experiments with non-dissociating mutants of fluorescently labeled Gαi1 subunits (exhibiting impaired dissociation from activated GPCRs) showed that 2PPM is capable of detecting GPCR-G protein interactions. 2PPM experiments with non-mutated fluorescently labeled Gαi1 subunits and α2A-adrenergic receptor, GABAB, or dopamine receptor type 2 receptors did not reveal any interaction between the Gi1 protein and the non-stimulated GPCRs. In contrast, non-stimulated CB1R exhibited an interaction with the Gi1 protein. Further experiments revealed that this interaction is caused solely by CB1R basal activity; no preassembly between CB1R and the Gi1 protein could be observed. Our results demonstrate that four diverse GPCRs do not preassemble with non-active Gi1 However, we also show that basal GPCR activity allows interactions between non-stimulated GPCRs and Gi1 (basal coupling). These findings suggest that Gi1 interacts only with active GPCRs and that the well known high speed of GPCR signal transduction does not require preassembly between G proteins and GPCRs.
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Affiliation(s)
- Alexey Bondar
- From the Center for Nanobiology and Structural Biology, Institute of Microbiology, Academy of Sciences of the Czech Republic, 37333 Nove Hrady,
| | - Josef Lazar
- From the Center for Nanobiology and Structural Biology, Institute of Microbiology, Academy of Sciences of the Czech Republic, 37333 Nove Hrady.,the Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 16610 Prague, and.,the Faculty of Science, University of South Bohemia, 37005 Ceske Budejovice, Czech Republic
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6
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Marivin A, Leyme A, Parag-Sharma K, DiGiacomo V, Cheung AY, Nguyen LT, Dominguez I, Garcia-Marcos M. Dominant-negative Gα subunits are a mechanism of dysregulated heterotrimeric G protein signaling in human disease. Sci Signal 2016; 9:ra37. [PMID: 27072656 DOI: 10.1126/scisignal.aad2429] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Auriculo-condylar syndrome (ACS), a rare condition that impairs craniofacial development, is caused by mutations in a G protein-coupled receptor (GPCR) signaling pathway. In mice, disruption of signaling by the endothelin type A receptor (ET(A)R), which is mediated by the G protein (heterotrimeric guanine nucleotide-binding protein) subunit Gα(q/11) and subsequently phospholipase C (PLC), impairs neural crest cell differentiation that is required for normal craniofacial development. Some ACS patients have mutations inGNAI3, which encodes Gα(i3), but it is unknown whether this G protein has a role within the ET(A)R pathway. We used a Xenopus model of vertebrate development, in vitro biochemistry, and biosensors of G protein activity in mammalian cells to systematically characterize the phenotype and function of all known ACS-associated Gα(i3) mutants. We found that ACS-associated mutations in GNAI3 produce dominant-negative Gα(i3) mutant proteins that couple to ET(A)R but cannot bind and hydrolyze guanosine triphosphate, resulting in the prevention of endothelin-mediated activation of Gα(q/11) and PLC. Thus, ACS is caused by functionally dominant-negative mutations in a heterotrimeric G protein subunit.
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Affiliation(s)
- Arthur Marivin
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA
| | - Anthony Leyme
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA
| | - Kshitij Parag-Sharma
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA
| | - Vincent DiGiacomo
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA
| | - Anthony Y Cheung
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA
| | - Lien T Nguyen
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA
| | - Isabel Dominguez
- Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
| | - Mikel Garcia-Marcos
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA.
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7
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Romero-Castillo RA, Roy Choudhury S, León-Félix J, Pandey S. Characterization of the heterotrimeric G-protein family and its transmembrane regulator from capsicum (Capsicum annuum L.). PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2015; 234:97-109. [PMID: 25804813 DOI: 10.1016/j.plantsci.2015.02.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 01/21/2015] [Accepted: 02/13/2015] [Indexed: 05/20/2023]
Abstract
Throughout evolution, organisms have created numerous mechanisms to sense and respond to their environment. One such highly conserved mechanism involves regulation by heterotrimeric G-protein complex comprised of alpha (Gα), beta (Gβ) and gamma (Gγ) subunits. In plants, these proteins play important roles in signal transduction pathways related to growth and development including response to biotic and abiotic stresses and consequently affect yield. In this work, we have identified and characterized the complete heterotrimeric G-protein repertoire in the Capsicum annuum (Capsicum) genome which consists of one Gα, one Gβ and three Gγ genes. We have also identified one RGS gene in the Capsicum genome that acts as a regulator of the G-protein signaling. Biochemical activities of the proteins were confirmed by assessing the GTP-binding and GTPase activity of the recombinant Gα protein and its regulation by the GTPase acceleration activity of the RGS protein. Interaction between different subunits was established using yeast- and plant-based analyses. Gene and protein expression profiles of specific G-protein components revealed interesting spatial and temporal regulation patterns, especially during root development and during fruit development and maturation. This research thus details the characterization of the first heterotrimeric G-protein family from a domesticated, commercially important vegetable crop.
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Affiliation(s)
- Rafael A Romero-Castillo
- Donald Danforth Plant Science Center, 975 North Warson Road, St. Louis, MO 63132, USA; Centro de Investigación en Alimentación y Desarrollo, A. C., Carretera a Eldorado km 5.5, Culiacán, Sinaloa, Mexico
| | - Swarup Roy Choudhury
- Donald Danforth Plant Science Center, 975 North Warson Road, St. Louis, MO 63132, USA
| | - Josefina León-Félix
- Centro de Investigación en Alimentación y Desarrollo, A. C., Carretera a Eldorado km 5.5, Culiacán, Sinaloa, Mexico
| | - Sona Pandey
- Donald Danforth Plant Science Center, 975 North Warson Road, St. Louis, MO 63132, USA.
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8
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Abstract
Experiments are described that allowed cross-linking of analogs of a 13-amino acid peptide into the binding site of a model G protein-coupled receptor. Syntheses of peptide analogs that were used for photochemical or chemical cross-linking were carried out using solid-phase peptide synthesis. Chemical cross-linking utilized 3,4-dihydroxy-l-phenylalanine-incorporated peptides and subsequent periodate-mediated activation, whereas photochemical cross-linking was mediated by p-benzoyl-l-phenylalanine (Bpa)-labeled peptides and UV-initiated activation. Mass spectrometry was employed to locate the site(s) in the receptor that formed the cross-links to the ligand. We also describe a method called unnatural amino acid replacement that allowed capture of a peptide ligand into the receptor. In this method, the receptor was genetically modified by replacement of a natural amino acid with Bpa. The modified receptor was UV-irradiated to capture the ligand. The approaches described are applicable to other peptide-binding proteins and can reveal the ligand-binding site in atomic detail.
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Affiliation(s)
| | - Fred Naider
- Chemistry Department, College of Staten Island, City University of New York
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9
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Roy Choudhury S, Wang Y, Pandey S. Soya bean Gα proteins with distinct biochemical properties exhibit differential ability to complement Saccharomyces cerevisiae gpa1 mutant. Biochem J 2014; 461:75-85. [PMID: 24694027 DOI: 10.1042/bj20131341] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Signalling pathways mediated by heterotrimeric G-proteins are common to all eukaryotes. Plants have a limited number of each of the G-protein subunits, with the most elaborate G-protein network discovered so far in soya bean (Glycine max, also known as soybean) which has four Gα, four Gβ and ten Gγ proteins. Biochemical characterization of Gα proteins from plants suggests significant variation in their properties compared with the well-characterized non-plant proteins. Furthermore, the four soya bean Gα (GmGα) proteins exhibit distinct biochemical activities among themselves, but the extent to which such biochemical differences contribute to their in vivo function is also not known. We used the yeast gpa1 mutant which displays constitutive signalling and growth arrest in the pheromone-response pathway as an in vivo model to evaluate the effect of distinct biochemical activities of GmGα proteins. We showed that specific GmGα proteins can be activated during pheromone-dependent receptor-mediated signalling in yeast and they display different strengths towards complementation of yeast gpa1 phenotypes. We also identified amino acids that are responsible for differential complementation abilities of specific Gα proteins. These data establish that specific plant Gα proteins are functional in the receptor-mediated pheromone-response pathway in yeast and that the subtle biochemical differences in their activity are physiologically relevant.
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Affiliation(s)
- Swarup Roy Choudhury
- *Donald Danforth Plant Science Center, 975 North Warson Road, St. Louis, MO 63132, U.S.A
| | - Yuqi Wang
- †Department of Biology, Saint Louis University, 3507 Laclede Avenue, St. Louis, MO 63103, U.S.A
| | - Sona Pandey
- *Donald Danforth Plant Science Center, 975 North Warson Road, St. Louis, MO 63132, U.S.A
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10
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A framework for mapping, visualisation and automatic model creation of signal-transduction networks. Mol Syst Biol 2012; 8:578. [PMID: 22531118 PMCID: PMC3361003 DOI: 10.1038/msb.2012.12] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
An intuitive formalism for reconstructing cellular networks from empirical data is presented, and used to build a comprehensive yeast MAP kinase network. The accompanying rxncon software tool can convert networks to a range of standard graphical formats and mathematical models. ![]()
Network mapping at the granularity of empirical data that largely avoids combinatorial complexity Automatic visualisation and model generation with the rxncon open source software tool Visualisation in a range of formats, including all three SBGN formats, as well as contingency matrix or regulatory graph Comprehensive and completely references map of the yeast MAP kinase network in the rxncon format
Intracellular signalling systems are highly complex. This complexity makes handling, analysis and visualisation of available knowledge a major challenge in current signalling research. Here, we present a novel framework for mapping signal-transduction networks that avoids the combinatorial explosion by breaking down the network in reaction and contingency information. It provides two new visualisation methods and automatic export to mathematical models. We use this framework to compile the presently most comprehensive map of the yeast MAP kinase network. Our method improves previous strategies by combining (I) more concise mapping adapted to empirical data, (II) individual referencing for each piece of information, (III) visualisation without simplifications or added uncertainty, (IV) automatic visualisation in multiple formats, (V) automatic export to mathematical models and (VI) compatibility with established formats. The framework is supported by an open source software tool that facilitates integration of the three levels of network analysis: definition, visualisation and mathematical modelling. The framework is species independent and we expect that it will have wider impact in signalling research on any system.
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Singh H, Endo Y, Nie G. Decidual HtrA3 negatively regulates trophoblast invasion during human placentation. Hum Reprod 2011; 26:748-57. [PMID: 21321049 DOI: 10.1093/humrep/der019] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Controlled trophoblast invasion into the maternal decidua (interstitial invasion) is important for placental development. Factors secreted by the maternal decidual cells and the extravillous trophoblast can influence trophoblast invasion and abnormalities in the invasion process may lead to pregnancy complications. Serine protease HtrA3 is highly expressed in the decidual cells in the late secretory phase of the menstrual cycle and throughout pregnancy, and in most trophoblast cell types, apart from the invading interstitial trophoblast during the first trimester. HtrA3 and its family members are down-regulated in a number of cancers and are proposed as tumour suppressors. The current study aimed to investigate whether HtrA3 is secreted by decidual cells, and whether inhibiting such secretion alters trophoblast invasion. METHODS AND RESULTS Human endometrial stromal cells (HESCs) were decidualized with estradiol, medroxyprogesterone acetate and cyclic adenosine monophosphate. Real-time RT-PCR, western blotting and immunocytochemistry confirmed that HtrA3 mRNA and protein expression increased during decidualization. HtrA3 was also detected in the conditioned media (CM) of the decidualized HESCs, confirming its secretion. For functional studies, a protease-inactive mutant form of HtrA3 which was previously confirmed to be a dominant-negative inhibitor was produced using wheat germ cell-free technology. CM from decidualized HESCs significantly suppressed invasion of trophoblast HTR-8 cells (P < 0.01), whereas inhibition of HtrA3 in this CM by exogenous HtrA3 mutant resulted in increased trophoblast HTR-8 cell invasion (P < 0.001). CONCLUSIONS These results strongly support the hypothesis that decidual HtrA3 negatively regulates trophoblast invasion.
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Affiliation(s)
- Harmeet Singh
- Prince Henry's Institute of Medical Research, PO Box 5152, 246 Clayton Road, Clayton, VIC 3168, Australia.
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12
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Inhibition of HTRA3 stimulates trophoblast invasion during human placental development. Placenta 2010; 31:1085-92. [DOI: 10.1016/j.placenta.2010.10.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Revised: 09/17/2010] [Accepted: 10/03/2010] [Indexed: 01/19/2023]
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13
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Abstract
Chemical gradients of peptide mating pheromones are necessary for directional growth, which is critical for yeast mating. These gradients are generated by cell-type specific secretion or export and specific degradation in receiving cells. Spatial information is sensed by dedicated seven-transmembrane G-protein coupled receptors and yeast cells are able to detect extremely small differences in ligand concentration across their approximately 5-microm cell surface. Here, I will discuss our current knowledge of how cells detect and respond to such shallow chemical gradients and in particular what is known about the proteins that are involved in directional growth and the establishment of the polarity axis during yeast mating.
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Affiliation(s)
- Robert A Arkowitz
- Institute of Developmental Biology and Cancer, Université de Nice-Sophia Antipolis-CNRS UMR6543, Centre de Biochimie, Faculté des Sciences, Parc Valrose, 06108 Nice Cedex 2, France.
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14
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Activated alleles of the Schizosaccharomyces pombe gpa2+ Galpha gene identify residues involved in GDP-GTP exchange. EUKARYOTIC CELL 2010; 9:626-33. [PMID: 20139237 DOI: 10.1128/ec.00010-10] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The Schizosaccharomyces pombe glucose/cyclic AMP (cAMP) signaling pathway includes the Gpa2-Git5-Git11 heterotrimeric G protein, whose Gpa2 Galpha subunit directly binds to and activates adenylate cyclase in response to signaling from the Git3 G protein-coupled receptor. To study intrinsic and extrinsic regulation of Gpa2, we developed a plasmid-based screen to identify mutationally activated gpa2 alleles that bypass the loss of the Git5-Git11 Gbetagamma dimer to repress transcription of the glucose-regulated fbp1(+) gene. Fifteen independently isolated mutations alter 11 different Gpa2 residues, with all but one conferring a receptor-independent activated phenotype upon integration into the gpa2(+) chromosomal locus. Biochemical characterization of three activated Gpa2 proteins demonstrated an increased GDP-GTP exchange rate that would explain the mechanism of activation. Interestingly, the amino acid altered in the Gpa2(V90A) exchange rate mutant protein is in a region of Gpa2 with no obvious role in Galpha function, thus extending our understanding of Galpha protein structure-function relationships.
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15
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Smith JL, Kupchak BR, Garitaonandia I, Hoang LK, Maina AS, Regalla LM, Lyons TJ. Heterologous expression of human mPRalpha, mPRbeta and mPRgamma in yeast confirms their ability to function as membrane progesterone receptors. Steroids 2008; 73:1160-73. [PMID: 18603275 PMCID: PMC2597464 DOI: 10.1016/j.steroids.2008.05.003] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2008] [Revised: 05/06/2008] [Accepted: 05/08/2008] [Indexed: 12/15/2022]
Abstract
The nuclear progesterone receptor (nPR) mediates many of the physiological effects of progesterone by regulating the expression of genes, however, progesterone also exerts non-transcriptional (non-genomic) effects that have been proposed to rely on a receptor that is distinct from nPR. Several members of the progestin and AdipoQ-Receptor (PAQR) family were recently identified as potential mediators of these non-genomic effects. Membranes from cells expressing these proteins, called mPRalpha, mPRbeta and mPRgamma, were shown to specifically bind progesterone and have G-protein coupled receptor (GPCR) characteristics, although other studies dispute these findings. To clarify the role of these mPRs in non-genomic progesterone signaling, we established an assay for PAQR functional evaluation using heterologous expression in Saccharomyces cerevisiae. Using this assay, we demonstrate unequivocally that mPRalpha, mPRbeta and mPRgamma can sense and respond to progesterone with EC(50) values that are physiologically relevant. Agonist profiles also show that mPRalpha, mPRbeta and mPRgamma are activated by ligands, such as 17alpha-hydroxyprogesterone, that are known to activate non-genomic pathways but not nPR. These results strongly suggest that these receptors may indeed function as the long-sought-after membrane progesterone receptors. Additionally, we show that two uncharacterized PAQRs, PAQR6 and PAQR9, are also capable of responding to progesterone. These mPR-like PAQRs have been renamed as mPRdelta (PAQR6) and mPRvarepsilon (PAQR9). Additional characterization of mPRgamma and mPRalpha indicates that their progesterone-dependent signaling in yeast does not require heterotrimeric G-proteins, thus calling into question the characterization of the mPRs as a novel class of G-protein coupled receptor.
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Affiliation(s)
- Jessica L. Smith
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, FL 32601
| | - Brian R. Kupchak
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, FL 32601
| | - Ibon Garitaonandia
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, FL 32601
| | - L. Kim Hoang
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, FL 32601
| | - Andrew S. Maina
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, FL 32601
| | - Lisa M. Regalla
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, FL 32601
| | - Thomas J. Lyons
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, FL 32601
- Corresponding author/reprint requests, University of Florida Department of Chemistry, P.O. Box 117200 Gainesville, FL 32611, tel: 352-846-3392, fax: 352-846-2095,
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16
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Lee MJ, Dohlman HG. Coactivation of G protein signaling by cell-surface receptors and an intracellular exchange factor. Curr Biol 2008; 18:211-5. [PMID: 18261907 DOI: 10.1016/j.cub.2008.01.007] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2007] [Revised: 12/27/2007] [Accepted: 01/03/2008] [Indexed: 10/22/2022]
Abstract
G protein-coupled receptors (GPCRs) mediate responses to a broad range of chemical and environmental signals. In yeast, a pheromone-binding GPCR triggers events leading to the fusion of haploid cells. In general, GPCRs function as guanine-nucleotide exchange factors (GEFs); upon agonist binding, the receptor induces a conformational change in the G protein alpha subunit, resulting in exchange of guanine diphosphate (GDP) for guanine triphosphate (GTP) and in signal initiation. Signaling is terminated when GTP is hydrolyzed to GDP [1]. This well-established paradigm has in recent years been revised to include new components that rates of GDP release, GTP binding [2-8], and GTP hydrolysis[9, 10]. Here we report the discovery of a nonreceptor GEF, Arr4. Like receptors, Arr4 binds directly to the G protein,accelerates guanine-nucleotide exchange, and stabilizes the nucleotide-free state of the a subunit. Moreover, Arr4 promotes G protein-dependent cellular responses, including mitogen-activated protein kinase (MAPK) phosphorylation,new-gene transcription, and mating. In contrast to knownGPCRs, however, Arr4 is not a transmembrane receptor,but rather a soluble intracellular protein. Our data suggest that intracellular proteins function in cooperation with mating pheromones to amplify G protein signaling, thereby leading to full pathway activation.
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Affiliation(s)
- Michael J Lee
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7365, USA
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17
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Shpakov AO, Pertseva MN. Chapter 4 Signaling Systems of Lower Eukaryotes and Their Evolution. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2008; 269:151-282. [DOI: 10.1016/s1937-6448(08)01004-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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18
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Buchwalter A, Van Dort C, Schultz S, Smith R, Le IP, Abbott JL, Oosterhouse E, Johnson AE, Hansen-Smith F, Burnatowska-Hledin M. Expression of VACM-1/cul5 mutant in endothelial cells induces MAPK phosphorylation and maspin degradation and converts cells to the angiogenic phenotype. Microvasc Res 2007; 75:155-68. [PMID: 17950367 DOI: 10.1016/j.mvr.2007.08.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2006] [Revised: 07/03/2007] [Accepted: 08/02/2007] [Indexed: 12/25/2022]
Abstract
Vasopressin-activated calcium mobilizing receptor (VACM-1) is a member of the cullin gene family involved in ubiquitin-proteosome dependent regulation of cellular functions. Expression of VACM-1 cDNA in cos-1 cells in vitro decreases basal cAMP levels and inhibits growth. The expression of (S730A)VACM-1 mutant cDNA, which removes PKA-dependent phosphorylation site in the VACM-1 cDNA sequence, reverses this phenotype. Since the expression of VACM-1 protein in vivo localizes largely to the vascular endothelial cells, in this study, we examined the effects of (S730A)VACM-1 cDNA expression on cellular signaling in the rat endothelial cell line RAMEC. Our results indicate that expression of (S730A)VACM-1 cDNA in RAMEC promotes cellular proliferation and induces angiogenic growth patterns. Western blot analyses indicate that (S730A)VACM-1 cDNA transfected cells express increased levels of Nedd8 modified VACM-1 and have higher levels of phosphorylated MAPK protein when compared to controls. Furthermore, expression of (S730A)VACM-1 cDNA induces translocation of the endogenous early response gene, egr-1, to the nucleus and leads to morphological changes that involve actin rearrangement. Finally, expression of (S730A)VACM-1 cDNA in RAMEC decreases concentration of maspin, a putative anti-angiogenic factor with a tumor suppressor activity. These results show that VACM-1 protein regulates endothelial cell growth and may modulate angiogenesis by a mechanism that involves MAPK phosphorylation, nuclear localization of egr-1, maspin expression, and actin polymerization.
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Affiliation(s)
- A Buchwalter
- Department of Biology and Chemistry, Science Center, Hope College, Holland, MI 49422-9000, USA
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19
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Shpakov AO. Serpentine type receptors and heterotrimeric G-proteins in yeasts: Structural-functional organization and molecular mechanisms of action. J EVOL BIOCHEM PHYS+ 2007. [DOI: 10.1134/s0022093007010012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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20
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Ballon DR, Flanary PL, Gladue DP, Konopka JB, Dohlman HG, Thorner J. DEP-domain-mediated regulation of GPCR signaling responses. Cell 2006; 126:1079-93. [PMID: 16990133 DOI: 10.1016/j.cell.2006.07.030] [Citation(s) in RCA: 154] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2006] [Revised: 06/09/2006] [Accepted: 07/19/2006] [Indexed: 11/22/2022]
Abstract
G protein-coupled receptors (GPCRs) mediate cellular responses to a variety of stimuli, but how specific responses are regulated has been elusive, as the types of GPCRs vastly outnumber the classes of G protein heterotrimers available to initiate downstream signaling. In our analysis of signaling proteins containing DEP domains ( approximately 90 residue sequence motifs first recognized in fly Dishevelled, worm EGL-10, and mammalian Pleckstrin), we find that DEP domains are responsible for specific recognition of GPCRs. We examined the yeast regulator of G protein signaling (RGS) protein Sst2 and demonstrate that the DEP domains in Sst2 mediate binding to its cognate GPCR (Ste2). DEP-domain-mediated tethering promotes downregulation by placing the RGS protein in proximity to its substrate (receptor-activated Galpha subunit). Sst2 docks to the Ste2 cytosolic tail, but only its unphosphorylated state, allowing for release and recycling of this regulator upon receptor desensitization and internalization. DEP-domain-mediated targeting of effectors and regulators to specific GPCRs provides a means to dictate the nature, duration, and specificity of the response.
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Affiliation(s)
- Daniel R Ballon
- Department of Molecular and Cell Biology, Division of Biochemistry and Molecular Biology, University of California, Berkeley, CA 94720, USA
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21
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Narayanaswamy R, Niu W, Scouras AD, Hart GT, Davies J, Ellington AD, Iyer VR, Marcotte EM. Systematic profiling of cellular phenotypes with spotted cell microarrays reveals mating-pheromone response genes. Genome Biol 2006; 7:R6. [PMID: 16507139 PMCID: PMC1431703 DOI: 10.1186/gb-2006-7-1-r6] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2005] [Revised: 10/14/2005] [Accepted: 01/10/2006] [Indexed: 11/10/2022] Open
Abstract
We have developed spotted cell microarrays for measuring cellular phenotypes on a large scale. Collections of cells are printed, stained for subcellular features, then imaged via automated, high-throughput microscopy, allowing systematic phenotypic characterization. We used this technology to identify genes involved in the response of yeast to mating pheromone. Besides morphology assays, cell microarrays should be valuable for high-throughput in situ hybridization and immunoassays, enabling new classes of genetic assays based on cell imaging.
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Affiliation(s)
- Rammohan Narayanaswamy
- Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, 2500 Speedway, University of Texas, Austin, TX 78712, USA
| | - Wei Niu
- Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, 2500 Speedway, University of Texas, Austin, TX 78712, USA
| | - Alexander D Scouras
- Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, 2500 Speedway, University of Texas, Austin, TX 78712, USA
| | - G Traver Hart
- Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, 2500 Speedway, University of Texas, Austin, TX 78712, USA
| | - Jonathan Davies
- Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, 2500 Speedway, University of Texas, Austin, TX 78712, USA
| | - Andrew D Ellington
- Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, 2500 Speedway, University of Texas, Austin, TX 78712, USA
| | - Vishwanath R Iyer
- Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, 2500 Speedway, University of Texas, Austin, TX 78712, USA
| | - Edward M Marcotte
- Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, 2500 Speedway, University of Texas, Austin, TX 78712, USA
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22
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Hein P, Frank M, Hoffmann C, Lohse MJ, Bünemann M. Dynamics of receptor/G protein coupling in living cells. EMBO J 2005; 24:4106-14. [PMID: 16292347 PMCID: PMC1356310 DOI: 10.1038/sj.emboj.7600870] [Citation(s) in RCA: 170] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2005] [Accepted: 10/19/2005] [Indexed: 12/26/2022] Open
Abstract
The interaction of activated G protein-coupled receptors with G proteins is a key event in signal transduction. Here, using a fluorescence resonance energy transfer (FRET)-based assay, we measure directly and in living cells the interaction of YFP-labeled alpha(2A)-adrenergic receptors with CFP-labeled G proteins. Upon agonist stimulation, a small, concentration-dependent increase in FRET was observed. No specific basal FRET was detected in the absence of agonist. Kinetics of the onset of receptor/G protein interaction were <100 ms and depended on expression levels of Galpha. Simultaneously recorded G protein-regulated inwardly rectifying K(+) channel currents revealed a maximal current response already at agonist concentrations producing submaximal FRET amplitudes. By analyzing FRET signals in the presence of a Galpha mutant, which dissociates more slowly from activated receptors, it was demonstrated that only a fraction of wild-type G proteins interacts with the activated receptor at any time. Our data suggest that alpha(2A)-adrenergic receptors and G proteins interact by rapid collision coupling and indicate that there is no significant precoupling between these receptors and G proteins.
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Affiliation(s)
- Peter Hein
- Department of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany
| | - Monika Frank
- Department of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany
| | - Carsten Hoffmann
- Department of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany
| | - Martin J Lohse
- Department of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany
| | - Moritz Bünemann
- Department of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany
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23
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Hoffman CS. Except in every detail: comparing and contrasting G-protein signaling in Saccharomyces cerevisiae and Schizosaccharomyces pombe. EUKARYOTIC CELL 2005; 4:495-503. [PMID: 15755912 PMCID: PMC1087802 DOI: 10.1128/ec.4.3.495-503.2005] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Charles S Hoffman
- Biology Department, Boston College, 140 Commonwealth Ave., Higgins Hall 401B, Chestnut Hill, MA 02467, USA.
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24
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Ladds G, Goddard A, Davey J. Functional analysis of heterologous GPCR signalling pathways in yeast. Trends Biotechnol 2005; 23:367-73. [PMID: 15923053 DOI: 10.1016/j.tibtech.2005.05.007] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2004] [Revised: 02/28/2005] [Accepted: 05/16/2005] [Indexed: 11/28/2022]
Abstract
G protein-coupled receptors (GPCRs) regulate diverse biological processes in eukaryotes and such conservation allows an almost unrestricted interchange of signalling components between different cell types. Yeasts are attractive hosts in which to study GPCRs--they are amenable to both genetic and biochemical manipulation and their robustness, low cost and our ability to create strains that lack endogenous GPCRs make them ideal starting points for the development of assays suitable for high-throughput screening. Here we introduce readers to the possibilities of using yeast to analyse GPCRs describing the endogenous signalling pathways, the development of assays for heterologous GPCRs and the technology to elucidate GPCR structure and activity, focusing on the budding yeast Saccharomyces cerevisiae and recent developments using the fission yeast Schizosaccharomyces pombe.
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Affiliation(s)
- Graham Ladds
- Department of Biological Sciences, University of Warwick, Coventry, CV4 7AL, UK
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