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Guidolin D, Tortorella C, Marcoli M, Cervetto C, De Caro R, Maura G, Agnati LF. Modulation of Neuron and Astrocyte Dopamine Receptors via Receptor-Receptor Interactions. Pharmaceuticals (Basel) 2023; 16:1427. [PMID: 37895898 PMCID: PMC10610355 DOI: 10.3390/ph16101427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 09/29/2023] [Accepted: 10/04/2023] [Indexed: 10/29/2023] Open
Abstract
Dopamine neurotransmission plays critical roles in regulating complex cognitive and behavioral processes including reward, motivation, reinforcement learning, and movement. Dopamine receptors are classified into five subtypes, widely distributed across the brain, including regions responsible for motor functions and specific areas related to cognitive and emotional functions. Dopamine also acts on astrocytes, which express dopamine receptors as well. The discovery of direct receptor-receptor interactions, leading to the formation of multimeric receptor complexes at the cell membrane and providing the cell decoding apparatus with flexible dynamics in terms of recognition and signal transduction, has expanded the knowledge of the G-protein-coupled receptor-mediated signaling processes. The purpose of this review article is to provide an overview of currently identified receptor complexes containing dopamine receptors and of their modulatory action on dopamine-mediated signaling between neurons and between neurons and astrocytes. Pharmacological possibilities offered by targeting receptor complexes in terms of addressing neuropsychiatric disorders associated with altered dopamine signaling will also be briefly discussed.
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Affiliation(s)
- Diego Guidolin
- Department of Neuroscience, University of Padova, 35122 Padova, Italy; (C.T.); (R.D.C.)
| | - Cinzia Tortorella
- Department of Neuroscience, University of Padova, 35122 Padova, Italy; (C.T.); (R.D.C.)
| | - Manuela Marcoli
- Department of Pharmacy, University of Genova, 16126 Genova, Italy; (M.M.); (C.C.); (G.M.)
| | - Chiara Cervetto
- Department of Pharmacy, University of Genova, 16126 Genova, Italy; (M.M.); (C.C.); (G.M.)
| | - Raffaele De Caro
- Department of Neuroscience, University of Padova, 35122 Padova, Italy; (C.T.); (R.D.C.)
| | - Guido Maura
- Department of Pharmacy, University of Genova, 16126 Genova, Italy; (M.M.); (C.C.); (G.M.)
| | - Luigi F. Agnati
- Department of Biomedical, Metabolic Sciences and Neuroscience, University of Modena and Reggio Emilia, 41121 Modena, Italy;
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2
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Hewitt N, Ma N, Arang N, Martin SA, Prakash A, DiBerto JF, Knight KM, Ghosh S, Olsen RHJ, Roth BL, Gutkind JS, Vaidehi N, Campbell SL, Dohlman HG. Catalytic site mutations confer multiple states of G protein activation. Sci Signal 2023; 16:eabq7842. [PMID: 36787384 PMCID: PMC10021883 DOI: 10.1126/scisignal.abq7842] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 01/31/2023] [Indexed: 02/16/2023]
Abstract
Heterotrimeric guanine nucleotide-binding proteins (G proteins) that function as molecular switches for cellular growth and metabolism are activated by GTP and inactivated by GTP hydrolysis. In uveal melanoma, a conserved glutamine residue critical for GTP hydrolysis in the G protein α subunit is often mutated in Gαq or Gα11 to either leucine or proline. In contrast, other glutamine mutations or mutations in other Gα subtypes are rare. To uncover the mechanism of the genetic selection and the functional role of this glutamine residue, we analyzed all possible substitutions of this residue in multiple Gα isoforms. Through cell-based measurements of activity, we showed that some mutants were further activated and inactivated by G protein-coupled receptors. Through biochemical, molecular dynamics, and nuclear magnetic resonance-based structural studies, we showed that the Gα mutants were functionally distinct and conformationally diverse, despite their shared inability to hydrolyze GTP. Thus, the catalytic glutamine residue contributes to functions beyond GTP hydrolysis, and these functions include subtype-specific, allosteric modulation of receptor-mediated subunit dissociation. We conclude that G proteins do not function as simple on-off switches. Rather, signaling emerges from an ensemble of active states, a subset of which are favored in disease and may be uniquely responsive to receptor-directed ligands.
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Affiliation(s)
- Natalie Hewitt
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Ning Ma
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
| | - Nadia Arang
- Department of Pharmacology, University of California San Diego, San Diego, CA, 92093, USA
- Moores Cancer Center, University of California San Diego, La Jolla, CA 92093, USA
| | - Sarah A. Martin
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Ajit Prakash
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jeffrey F. DiBerto
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Kevin M. Knight
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Soumadwip Ghosh
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
- Current address: Illumina Inc, 5200 Illumina Way, San Diego, CA 92037, USA
| | - Reid H. J. Olsen
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Current address: GPCR Pharmacology, Discovery Biology, Exscientia Ai, Oxford, UK OX4 4GE
| | - Bryan L. Roth
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - J. Silvio Gutkind
- Department of Pharmacology, University of California San Diego, San Diego, CA, 92093, USA
- Moores Cancer Center, University of California San Diego, La Jolla, CA 92093, USA
| | - Nagarajan Vaidehi
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
| | - Sharon L. Campbell
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Henrik G. Dohlman
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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3
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Dumont ME, Konopka JB. Comparison of Experimental Approaches Used to Determine the Structure and Function of the Class D G Protein-Coupled Yeast α-Factor Receptor. Biomolecules 2022; 12:biom12060761. [PMID: 35740886 PMCID: PMC9220813 DOI: 10.3390/biom12060761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 05/26/2022] [Accepted: 05/27/2022] [Indexed: 02/01/2023] Open
Abstract
The Saccharomyces cerevisiae α-factor mating pheromone receptor (Ste2p) has been studied as a model for the large medically important family of G protein-coupled receptors. Diverse yeast genetic screens and high-throughput mutagenesis of STE2 identified a large number of loss-of-function, constitutively-active, dominant-negative, and intragenic second-site suppressor mutants as well as mutations that specifically affect pheromone binding. Facile genetic manipulation of Ste2p also aided in targeted biochemical approaches, such as probing the aqueous accessibility of substituted cysteine residues in order to identify the boundaries of the seven transmembrane segments, and the use of cysteine disulfide crosslinking to identify sites of intramolecular contacts in the transmembrane helix bundle of Ste2p and sites of contacts between the monomers in a Ste2p dimer. Recent publication of a series of high-resolution cryo-EM structures of Ste2p in ligand-free, agonist-bound and antagonist-bound states now makes it possible to evaluate the results of these genetic and biochemical strategies, in comparison to three-dimensional structures showing activation-related conformational changes. The results indicate that the genetic and biochemical strategies were generally effective, and provide guidance as to how best to apply these experimental strategies to other proteins. These strategies continue to be useful in defining mechanisms of signal transduction in the context of the available structures and suggest aspects of receptor function beyond what can be discerned from the available structures.
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Affiliation(s)
- Mark E. Dumont
- Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, NY 14642, USA
- Correspondence: ; Tel.: +1-585-275-2466
| | - James B. Konopka
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY 11794-5222, USA;
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4
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Guidolin D, Tortorella C, Marcoli M, Maura G, Agnati LF. Intercellular Communication in the Central Nervous System as Deduced by Chemical Neuroanatomy and Quantitative Analysis of Images: Impact on Neuropharmacology. Int J Mol Sci 2022; 23:5805. [PMID: 35628615 PMCID: PMC9145073 DOI: 10.3390/ijms23105805] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 05/19/2022] [Accepted: 05/20/2022] [Indexed: 01/25/2023] Open
Abstract
In the last decades, new evidence on brain structure and function has been acquired by morphological investigations based on synergic interactions between biochemical anatomy approaches, new techniques in microscopy and brain imaging, and quantitative analysis of the obtained images. This effort produced an expanded view on brain architecture, illustrating the central nervous system as a huge network of cells and regions in which intercellular communication processes, involving not only neurons but also other cell populations, virtually determine all aspects of the integrative function performed by the system. The main features of these processes are described. They include the two basic modes of intercellular communication identified (i.e., wiring and volume transmission) and mechanisms modulating the intercellular signaling, such as cotransmission and allosteric receptor-receptor interactions. These features may also open new possibilities for the development of novel pharmacological approaches to address central nervous system diseases. This aspect, with a potential major impact on molecular medicine, will be also briefly discussed.
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Affiliation(s)
- Diego Guidolin
- Department of Neuroscience, Section of Anatomy, University of Padova, 35121 Padova, Italy;
| | - Cinzia Tortorella
- Department of Neuroscience, Section of Anatomy, University of Padova, 35121 Padova, Italy;
| | - Manuela Marcoli
- Department of Pharmacy, Center of Excellence for Biomedical Research, University of Genova, 16126 Genova, Italy; (M.M.); (G.M.)
| | - Guido Maura
- Department of Pharmacy, Center of Excellence for Biomedical Research, University of Genova, 16126 Genova, Italy; (M.M.); (G.M.)
| | - Luigi F. Agnati
- Department of Biomedical Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy;
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5
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Velazhahan V, Ma N, Vaidehi N, Tate CG. Activation mechanism of the class D fungal GPCR dimer Ste2. Nature 2022; 603:743-748. [PMID: 35296853 PMCID: PMC8942848 DOI: 10.1038/s41586-022-04498-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Accepted: 02/01/2022] [Indexed: 02/06/2023]
Abstract
The fungal class D1 G-protein-coupled receptor (GPCR) Ste2 has a different arrangement of transmembrane helices compared with mammalian GPCRs and a distinct mode of coupling to the heterotrimeric G protein Gpa1-Ste2-Ste181. In addition, Ste2 lacks conserved sequence motifs such as DRY, PIF and NPXXY, which are associated with the activation of class A GPCRs2. This suggested that the activation mechanism of Ste2 may also differ. Here we determined structures of Saccharomyces cerevisiae Ste2 in the absence of G protein in two different conformations bound to the native agonist α-factor, bound to an antagonist and without ligand. These structures revealed that Ste2 is indeed activated differently from other GPCRs. In the inactive state, the cytoplasmic end of transmembrane helix H7 is unstructured and packs between helices H1-H6, blocking the G protein coupling site. Agonist binding results in the outward movement of the extracellular ends of H6 and H7 by 6 Å. On the intracellular surface, the G protein coupling site is formed by a 20 Å outward movement of the unstructured region in H7 that unblocks the site, and a 12 Å inward movement of H6. This is a distinct mechanism in GPCRs, in which the movement of H6 and H7 upon agonist binding facilitates G protein coupling.
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Affiliation(s)
| | - Ning Ma
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, Duarte, CA, USA
| | - Nagarajan Vaidehi
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, Duarte, CA, USA
| | - Christopher G Tate
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, UK.
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6
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Liu T, Ji RL, Tao YX. Naturally occurring mutations in G protein-coupled receptors associated with obesity and type 2 diabetes mellitus. Pharmacol Ther 2021; 234:108044. [PMID: 34822948 DOI: 10.1016/j.pharmthera.2021.108044] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 11/15/2021] [Accepted: 11/15/2021] [Indexed: 12/12/2022]
Abstract
G protein-coupled receptors (GPCRs) are the largest family of membrane receptors involved in the regulation of almost all known physiological processes. Dysfunctions of GPCR-mediated signaling have been shown to cause various diseases. The prevalence of obesity and type 2 diabetes mellitus (T2DM), two strongly associated disorders, is increasing worldwide, with tremendous economical and health burden. New safer and more efficacious drugs are required for successful weight reduction and T2DM treatment. Multiple GPCRs are involved in the regulation of energy and glucose homeostasis. Mutations in these GPCRs contribute to the development and progression of obesity and T2DM. Therefore, these receptors can be therapeutic targets for obesity and T2DM. Indeed some of these receptors, such as melanocortin-4 receptor and glucagon-like peptide 1 receptor, have provided important new drugs for treating obesity and T2DM. This review will focus on the naturally occurring mutations of several GPCRs associated with obesity and T2DM, especially incorporating recent large genomic data and insights from structure-function studies, providing leads for future investigations.
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Affiliation(s)
- Ting Liu
- Department of Anatomy, Physiology and Pharmacology, Auburn University College of Veterinary Medicine, Auburn, AL 36849, United States
| | - Ren-Lei Ji
- Department of Anatomy, Physiology and Pharmacology, Auburn University College of Veterinary Medicine, Auburn, AL 36849, United States
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, Auburn University College of Veterinary Medicine, Auburn, AL 36849, United States.
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7
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Connelly SM, Sridharan R, Naider F, Dumont ME. Oligomerization of yeast α-factor receptor detected by fluorescent energy transfer between ligands. Biophys J 2021; 120:5090-5106. [PMID: 34627767 DOI: 10.1016/j.bpj.2021.10.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 08/26/2021] [Accepted: 10/05/2021] [Indexed: 11/26/2022] Open
Abstract
G-protein-coupled receptors (GPCRs) comprise a large superfamily of transmembrane receptors responsible for transducing responses to the binding of a wide variety of hormones, neurotransmitters, ions, and other small molecules. There is extensive evidence that GPCRs exist as homo-and hetero-oligomeric complexes; however, in many cases, the role of oligomerization and the extent to which it occurs at low physiological levels of receptor expression in cells remain unclear. We report here the use of flow cytometry to detect receptor-receptor interactions based on fluorescence resonance energy transfer between fluorescently labeled cell-impermeant ligands bound to yeast α-mating pheromone receptors that are members of the GPCR superfamily. A novel, to our knowledge, procedure was used to analyze energy transfer as a function of receptor occupancy by donor and acceptor ligands. Measurements of loss of donor fluorescence due to energy transfer in cells expressing high levels of receptors were used to calibrate measurements of enhanced acceptor emission due to energy transfer in cells expressing low levels of receptors. The procedure allows determination of energy transfer efficiencies over a 50-fold range of expression of full-length receptors at the surface of living cells without the need to create fluorescent or bioluminescent fusion proteins. Energy transfer efficiencies for fluorescently labeled derivatives of the receptor agonist α-factor do not depend on receptor expression level and are unaffected by C-terminal truncation of receptors. Fluorescently labeled derivatives of α-factor that act as receptor antagonists exhibit higher transfer efficiencies than those for labeled agonists. Although the approach cannot determine the number of receptors per oligomer, these results demonstrate that ligand-bound, native α-factor receptors exist as stable oligomers in the cell membranes of intact yeast cells at normal physiological expression levels and that the extent of oligomer formation is not dependent on the concentration of receptors in the membrane.
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Affiliation(s)
- Sara M Connelly
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | - Rajashri Sridharan
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | - Fred Naider
- Department of Chemistry and Macromolecular Assembly Institute, College of Staten Island of the City University of New York, Staten Island, New York; PhD Programs in Biochemistry and Chemistry, The Graduate Center of the City University of New York, New York, New York
| | - Mark E Dumont
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, New York.
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8
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Cevheroğlu O, Murat M, Mingu-Akmete S, Son ÇD. Ste2p Under the Microscope: the Investigation of Oligomeric States of a Yeast G Protein-Coupled Receptor. J Phys Chem B 2021; 125:9526-9536. [PMID: 34433281 DOI: 10.1021/acs.jpcb.1c05872] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Oligomerization of G protein-coupled receptors (GPCRs) may play important roles in maturation, internalization, signaling, and pharmacology of these receptors. However, the nature and extent of their oligomerization is still under debate. In our study, Ste2p, a yeast mating pheromone GPCR, was tagged with enhanced green fluorescent protein (EGFP), mCherry, and with split florescent protein fragments at the receptor C-terminus. The Förster resonance energy transfer (FRET) technique was used to detect receptors' oligomerization by calculating the energy transfer from EGFP to mCherry. Stimulation of Ste2p oligomers with the receptor ligand did not result in any significant change on observed FRET values. The bimolecular fluorescence complementation (BiFC) assay was combined with FRET to further investigate the tetrameric complexes of Ste2p. Our results suggest that in its quiescent (nonligand-activated) state, Ste2p is found at least as a tetrameric complex on the plasma membrane. Intriguingly, receptor tetramers in their active form showed a significant increase in FRET. This study provides a direct in vivo visualization of Ste2p tetramers and the pheromone effect on the extent of the receptor oligomerization.
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Affiliation(s)
- Orkun Cevheroğlu
- Stem Cell Institute, Ankara University, Cankaya, 06520 Ankara, Turkey
| | - Merve Murat
- Stem Cell Institute, Ankara University, Cankaya, 06520 Ankara, Turkey.,Department of Biological Sciences, Middle East Technical University, Cankaya, 06800 Ankara, Turkey
| | - Sara Mingu-Akmete
- Stem Cell Institute, Ankara University, Cankaya, 06520 Ankara, Turkey.,Department of Biological Sciences, Middle East Technical University, Cankaya, 06800 Ankara, Turkey
| | - Çağdaş D Son
- Department of Biological Sciences, Middle East Technical University, Cankaya, 06800 Ankara, Turkey
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9
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Guidolin D, Tortorella C, Marcoli M, Cervetto C, Maura G, Agnati LF. Receptor-Receptor Interactions and Glial Cell Functions with a Special Focus on G Protein-Coupled Receptors. Int J Mol Sci 2021; 22:8656. [PMID: 34445362 PMCID: PMC8395429 DOI: 10.3390/ijms22168656] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 07/30/2021] [Accepted: 08/11/2021] [Indexed: 12/18/2022] Open
Abstract
The discovery that receptors from all families can establish allosteric receptor-receptor interactions and variably associate to form receptor complexes operating as integrative input units endowed with a high functional and structural plasticity has expanded our understanding of intercellular communication. Regarding the nervous system, most research in the field has focused on neuronal populations and has led to the identification of many receptor complexes representing an important mechanism to fine-tune synaptic efficiency. Receptor-receptor interactions, however, also modulate glia-neuron and glia-glia intercellular communication, with significant consequences on synaptic activity and brain network plasticity. The research on this topic is probably still at the beginning and, here, available evidence will be reviewed and discussed. It may also be of potential interest from a pharmacological standpoint, opening the possibility to explore, inter alia, glia-based neuroprotective therapeutic strategies.
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Affiliation(s)
- Diego Guidolin
- Department of Neuroscience, Section of Anatomy, University of Padova, 35121 Padova, Italy;
| | - Cinzia Tortorella
- Department of Neuroscience, Section of Anatomy, University of Padova, 35121 Padova, Italy;
| | - Manuela Marcoli
- Department of Pharmacy, Center of Excellence for Biomedical Research, University of Genova, 16126 Genova, Italy; (M.M.); (C.C.); (G.M.)
| | - Chiara Cervetto
- Department of Pharmacy, Center of Excellence for Biomedical Research, University of Genova, 16126 Genova, Italy; (M.M.); (C.C.); (G.M.)
| | - Guido Maura
- Department of Pharmacy, Center of Excellence for Biomedical Research, University of Genova, 16126 Genova, Italy; (M.M.); (C.C.); (G.M.)
| | - Luigi F. Agnati
- Department of Biomedical Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy;
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10
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Dielectric Spectroscopy Based Detection of Specific and Nonspecific Cellular Mechanisms. SENSORS 2021; 21:s21093177. [PMID: 34063599 PMCID: PMC8124793 DOI: 10.3390/s21093177] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 04/29/2021] [Accepted: 04/30/2021] [Indexed: 12/14/2022]
Abstract
Using radiofrequency dielectric spectroscopy, we have investigated the impact of the interaction between a G protein-coupled receptor (GPCR), the sterile2 α-factor receptor protein (Ste2), and its cognate agonist ligand, the α-factor pheromone, on the dielectric properties of the plasma membrane in living yeast cells (Saccharomyces cerevisiae). The dielectric properties of a cell suspension containing a saturating concentration of α-factor were measured over the frequency range 40Hz–110 MHz and compared to the behavior of a similarly prepared suspension of cells in the absence of α-factor. A spherical three-shell model was used to determine the electrical phase parameters for the yeast cells in both types of suspensions. The relative permittivity of the plasma membrane showed a significant increase after exposure to α-factor (by 0.06 ± 0.05). The equivalent experiment performed on yeast cells lacking the ability to express Ste2 showed no change in plasma membrane permittivity. Interestingly, a large change also occurred to the electrical properties of the cellular interior after the addition of α-factor to the cell suspending medium, whether or not the cells were expressing Ste2. We present a number of different complementary experiments performed on the yeast to support these dielectric data and interpret the results in terms of specific cellular reactions to the presence of α-factor.
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11
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Velazhahan V, Ma N, Pándy-Szekeres G, Kooistra AJ, Lee Y, Gloriam DE, Vaidehi N, Tate CG. Structure of the class D GPCR Ste2 dimer coupled to two G proteins. Nature 2020; 589:148-153. [PMID: 33268889 PMCID: PMC7116888 DOI: 10.1038/s41586-020-2994-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 09/25/2020] [Indexed: 01/08/2023]
Abstract
G-protein-coupled receptors (GPCRs) are divided phylogenetically into six classes1,2, denoted A to F. More than 370 structures of vertebrate GPCRs (belonging to classes A, B, C and F) have been determined, leading to a substantial understanding of their function3. By contrast, there are no structures of class D GPCRs, which are found exclusively in fungi where they regulate survival and reproduction. Here we determine the structure of a class D GPCR, the Saccharomyces cerevisiae pheromone receptor Ste2, in an active state coupled to the heterotrimeric G protein Gpa1-Ste4-Ste18. Ste2 was purified as a homodimer coupled to two G proteins. The dimer interface of Ste2 is formed by the N terminus, the transmembrane helices H1, H2 and H7, and the first extracellular loop ECL1. We establish a class D1 generic residue numbering system (CD1) to enable comparisons with orthologues and with other GPCR classes. The structure of Ste2 bears similarities in overall topology to class A GPCRs, but the transmembrane helix H4 is shifted by more than 20 Å and the G-protein-binding site is a shallow groove rather than a cleft. The structure provides a template for the design of novel drugs to target fungal GPCRs, which could be used to treat numerous intractable fungal diseases4.
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Affiliation(s)
| | - Ning Ma
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, Duarte, CA, USA
| | - Gáspár Pándy-Szekeres
- Department of Drug Design and Pharmacology, Universitetsparken 2, Copenhagen, Denmark.,Medicinal Chemistry Research Group, Research Center for Natural Sciences, Budapest, Hungary
| | - Albert J Kooistra
- Department of Drug Design and Pharmacology, Universitetsparken 2, Copenhagen, Denmark
| | - Yang Lee
- MRC Laboratory of Molecular Biology, Cambridge, UK
| | - David E Gloriam
- Department of Drug Design and Pharmacology, Universitetsparken 2, Copenhagen, Denmark
| | - Nagarajan Vaidehi
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, Duarte, CA, USA
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12
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Paprocki J, Biener G, Stoneman M, Raicu V. In-Cell Detection of Conformational Substates of a G Protein-Coupled Receptor Quaternary Structure: Modulation of Substate Probability by Cognate Ligand Binding. J Phys Chem B 2020; 124:10062-10076. [DOI: 10.1021/acs.jpcb.0c06081] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Joel Paprocki
- Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, United States
| | - Gabriel Biener
- Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, United States
| | - Michael Stoneman
- Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, United States
| | - Valerică Raicu
- Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, United States
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, United States
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13
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Skruzny M, Pohl E, Abella M. FRET Microscopy in Yeast. BIOSENSORS 2019; 9:E122. [PMID: 31614546 PMCID: PMC6956097 DOI: 10.3390/bios9040122] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 09/19/2019] [Accepted: 09/30/2019] [Indexed: 02/06/2023]
Abstract
Förster resonance energy transfer (FRET) microscopy is a powerful fluorescence microscopy method to study the nanoscale organization of multiprotein assemblies in vivo. Moreover, many biochemical and biophysical processes can be followed by employing sophisticated FRET biosensors directly in living cells. Here, we summarize existing FRET experiments and biosensors applied in yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe, two important models of fundamental biomedical research and efficient platforms for analyses of bioactive molecules. We aim to provide a practical guide on suitable FRET techniques, fluorescent proteins, and experimental setups available for successful FRET experiments in yeasts.
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Affiliation(s)
- Michal Skruzny
- Department of Systems and Synthetic Microbiology, Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany.
- LOEWE Center for Synthetic Microbiology (SYNMIKRO), 35043 Marburg, Germany.
| | - Emma Pohl
- Department of Systems and Synthetic Microbiology, Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
- LOEWE Center for Synthetic Microbiology (SYNMIKRO), 35043 Marburg, Germany
| | - Marc Abella
- Department of Systems and Synthetic Microbiology, Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
- LOEWE Center for Synthetic Microbiology (SYNMIKRO), 35043 Marburg, Germany
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14
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Sil P, Mateos N, Nath S, Buschow S, Manzo C, Suzuki KGN, Fujiwara T, Kusumi A, Garcia-Parajo MF, Mayor S. Dynamic actin-mediated nano-scale clustering of CD44 regulates its meso-scale organization at the plasma membrane. Mol Biol Cell 2019; 31:561-579. [PMID: 31577524 PMCID: PMC7202065 DOI: 10.1091/mbc.e18-11-0715] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Transmembrane adhesion receptors at the cell surface, such as CD44, are often equipped with modules to interact with the extracellular matrix (ECM) and the intracellular cytoskeletal machinery. CD44 has been recently shown to compartmentalize the membrane into domains by acting as membrane pickets, facilitating the function of signaling receptors. While spatial organization and diffusion studies of membrane proteins are usually conducted separately, here we combine observations of organization and diffusion by using high spatio-temporal resolution imaging on living cells to reveal a hierarchical organization of CD44. CD44 is present in a meso-scale meshwork pattern where it exhibits enhanced confinement and is enriched in nanoclusters of CD44 along its boundaries. This nanoclustering is orchestrated by the underlying cortical actin dynamics. Interaction with actin is mediated by specific segments of the intracellular domain. This influences the organization of the protein at the nano-scale, generating a selective requirement for formin over Arp2/3-based actin-nucleation machinery. The extracellular domain and its interaction with elements of ECM do not influence the meso-scale organization, but may serve to reposition the meshwork with respect to the ECM. Taken together, our results capture the hierarchical nature of CD44 organization at the cell surface, with active cytoskeleton-templated nanoclusters localized to a meso-scale meshwork pattern.
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Affiliation(s)
- Parijat Sil
- National Centre for Biological Sciences (NCBS)
| | - Nicolas Mateos
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Barcelona 08860, Spain
| | - Sangeeta Nath
- Institute of Stem Cell and Regenerative Medicine.,Manipal Institute of Regenerative Medicine, Manipal Academy of Higher Education, Bangalore 560065, India
| | - Sonja Buschow
- Department of Gastroenterology and Hepatology, Erasmus University Medical Center Rotterdam, Rotterdam 3015 GD Rotterdam, The Netherlands
| | - Carlo Manzo
- Facultat de Ciències i Tecnologia, Universitat de Vic-Universitat Central de Catalunya, Vic 08500, Spain
| | - Kenichi G N Suzuki
- Centre for Highly Advanced Integration of Nano and Life Sciences (G-CHAIN), Gifu University, Gifu 501-1193, Japan.,Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto 606-8501, Japan
| | - Takahiro Fujiwara
- Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto 606-8501, Japan
| | - Akihiro Kusumi
- Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto 606-8501, Japan.,Okinawa Institute of Science and Technology, Graduate University, Okinawa 904-0412, Japan
| | - Maria F Garcia-Parajo
- Institute of Stem Cell and Regenerative Medicine.,Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain
| | - Satyajit Mayor
- National Centre for Biological Sciences (NCBS).,Institute of Stem Cell and Regenerative Medicine
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15
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Wang X, Tian W, Banh BT, Statler BM, Liang J, Stone DE. Mating yeast cells use an intrinsic polarity site to assemble a pheromone-gradient tracking machine. J Cell Biol 2019; 218:3730-3752. [PMID: 31570500 PMCID: PMC6829655 DOI: 10.1083/jcb.201901155] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 06/06/2019] [Accepted: 08/08/2019] [Indexed: 12/12/2022] Open
Abstract
The mating of budding yeast depends on chemotropism, a fundamental cellular process. The two yeast mating types secrete peptide pheromones that bind to GPCRs on cells of the opposite type. Cells find and contact a partner by determining the direction of the pheromone source and polarizing their growth toward it. Actin-directed secretion to the chemotropic growth site (CS) generates a mating projection. When pheromone-stimulated cells are unable to sense a gradient, they form mating projections where they would have budded in the next cell cycle, at a position called the default polarity site (DS). Numerous models have been proposed to explain yeast gradient sensing, but none address how cells reliably switch from the intrinsically determined DS to the gradient-aligned CS, despite a weak spatial signal. Here we demonstrate that, in mating cells, the initially uniform receptor and G protein first polarize to the DS, then redistribute along the plasma membrane until they reach the CS. Our data indicate that signaling, polarity, and trafficking proteins localize to the DS during assembly of what we call the gradient tracking machine (GTM). Differential activation of the receptor triggers feedback mechanisms that bias exocytosis upgradient and endocytosis downgradient, thus enabling redistribution of the GTM toward the pheromone source. The GTM stabilizes when the receptor peak centers at the CS and the endocytic machinery surrounds it. A computational model simulates GTM tracking and stabilization and correctly predicts that its assembly at a single site contributes to mating fidelity.
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Affiliation(s)
- Xin Wang
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL
| | - Wei Tian
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL
| | - Bryan T Banh
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL
| | | | - Jie Liang
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL
| | - David E Stone
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL
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16
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Planes N, Digman MA, Vanderheyden PP, Gratton E, Caballero-George C. Number and brightness analysis to study spatio-temporal distribution of the angiotensin II AT1 and the endothelin-1 ETA receptors: Influence of ligand binding. Biochim Biophys Acta Gen Subj 2019; 1863:917-924. [DOI: 10.1016/j.bbagen.2019.03.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 02/18/2019] [Accepted: 03/05/2019] [Indexed: 02/04/2023]
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17
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Weinberg ZY, Puthenveedu MA. Regulation of G protein-coupled receptor signaling by plasma membrane organization and endocytosis. Traffic 2019; 20:121-129. [PMID: 30536564 PMCID: PMC6415975 DOI: 10.1111/tra.12628] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 11/27/2018] [Accepted: 12/05/2018] [Indexed: 12/11/2022]
Abstract
The trafficking of G protein coupled-receptors (GPCRs) is one of the most exciting areas in cell biology because of recent advances demonstrating that GPCR signaling is spatially encoded. GPCRs, acting in a diverse array of physiological systems, can have differential signaling consequences depending on their subcellular localization. At the plasma membrane, GPCR organization could fine-tune the initial stages of receptor signaling by determining the magnitude of signaling and the type of effectors to which receptors can couple. This organization is mediated by the lipid composition of the plasma membrane, receptor-receptor interactions, and receptor interactions with intracellular scaffolding proteins. GPCR organization is subsequently changed by ligand binding and the regulated endocytosis of these receptors. Activated GPCRs can modulate the dynamics of their own endocytosis through changing clathrin-coated pit dynamics, and through the scaffolding adaptor protein β-arrestin. This endocytic regulation has signaling consequences, predominantly through modulation of the MAPK cascade. This review explores what is known about receptor sorting at the plasma membrane, protein partners that control receptor endocytosis, and the ways in which receptor sorting at the plasma membrane regulates downstream trafficking and signaling.
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Affiliation(s)
- Zara Y Weinberg
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan
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18
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Discs large 1 controls daughter-cell polarity after cytokinesis in vertebrate morphogenesis. Proc Natl Acad Sci U S A 2018; 115:E10859-E10868. [PMID: 30377270 DOI: 10.1073/pnas.1713959115] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Vertebrate embryogenesis and organogenesis are driven by cell biological processes, ranging from mitosis and migration to changes in cell size and polarity, but their control and causal relationships are not fully defined. Here, we use the developing limb skeleton to better define the relationships between mitosis and cell polarity. We combine protein-tagging and -perturbation reagents with advanced in vivo imaging to assess the role of Discs large 1 (Dlg1), a membrane-associated scaffolding protein, in mediating the spatiotemporal relationship between cytokinesis and cell polarity. Our results reveal that Dlg1 is enriched at the midbody during cytokinesis and that its multimerization is essential for the normal polarity of daughter cells. Defects in this process alter tissue dimensions without impacting other cellular processes. Our results extend the conventional view that division orientation is established at metaphase and anaphase and suggest that multiple mechanisms act at distinct phases of the cell cycle to transmit cell polarity. The approach employed can be used in other systems, as it offers a robust means to follow and to eliminate protein function and extends the Phasor approach for studying in vivo protein interactions by frequency-domain fluorescence lifetime imaging microscopy of Förster resonance energy transfer (FLIM-FRET) to organotypic explant culture.
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19
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Emmerstorfer-Augustin A, Augustin CM, Shams S, Thorner J. Tracking yeast pheromone receptor Ste2 endocytosis using fluorogen-activating protein tagging. Mol Biol Cell 2018; 29:2720-2736. [PMID: 30207829 PMCID: PMC6249837 DOI: 10.1091/mbc.e18-07-0424] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
To observe internalization of the yeast pheromone receptor Ste2 by fluorescence microscopy in live cells in real time, we visualized only those molecules present at the cell surface at the time of agonist engagement (rather than the total cellular pool) by tagging this receptor at its N-terminus with an exocellular fluorogen-activating protein (FAP). A FAP is a single-chain antibody engineered to bind tightly a nonfluorescent, cell-impermeable dye (fluorogen), thereby generating a fluorescent complex. The utility of FAP tagging to study trafficking of integral membrane proteins in yeast, which possesses a cell wall, had not been examined previously. A diverse set of signal peptides and propeptide sequences were explored to maximize expression. Maintenance of the optimal FAP-Ste2 chimera intact required deletion of two, paralogous, glycosylphosphatidylinositol (GPI)-anchored extracellular aspartyl proteases (Yps1 and Mkc7). FAP-Ste2 exhibited a much brighter and distinct plasma membrane signal than Ste2-GFP or Ste2-mCherry yet behaved quite similarly. Using FAP-Ste2, new information was obtained about the mechanism of its internalization, including novel insights about the roles of the cargo-selective endocytic adaptors Ldb19/Art1, Rod1/Art4, and Rog3/Art7.
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Affiliation(s)
- Anita Emmerstorfer-Augustin
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3202
| | - Christoph M Augustin
- Department of Mechanical Engineering, University of California, Berkeley, Berkeley, CA 94720-3202
| | - Shadi Shams
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3202
| | - Jeremy Thorner
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3202
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20
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Borroto-Escuela DO, Rodriguez D, Romero-Fernandez W, Kapla J, Jaiteh M, Ranganathan A, Lazarova T, Fuxe K, Carlsson J. Mapping the Interface of a GPCR Dimer: A Structural Model of the A 2A Adenosine and D 2 Dopamine Receptor Heteromer. Front Pharmacol 2018; 9:829. [PMID: 30214407 PMCID: PMC6125358 DOI: 10.3389/fphar.2018.00829] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 07/10/2018] [Indexed: 12/17/2022] Open
Abstract
The A2A adenosine (A2AR) and D2 dopamine (D2R) receptors form oligomers in the cell membrane and allosteric interactions across the A2AR–D2R heteromer represent a target for development of drugs against central nervous system disorders. However, understanding of the molecular determinants of A2AR–D2R heteromerization and the allosteric antagonistic interactions between the receptor protomers is still limited. In this work, a structural model of the A2AR–D2R heterodimer was generated using a combined experimental and computational approach. Regions involved in the heteromer interface were modeled based on the effects of peptides derived from the transmembrane (TM) helices on A2AR–D2R receptor–receptor interactions in bioluminescence resonance energy transfer (BRET) and proximity ligation assays. Peptides corresponding to TM-IV and TM-V of the A2AR blocked heterodimer interactions and disrupted the allosteric effect of A2AR activation on D2R agonist binding. Protein–protein docking was used to construct a model of the A2AR–D2R heterodimer with a TM-IV/V interface, which was refined using molecular dynamics simulations. Mutations in the predicted interface reduced A2AR–D2R interactions in BRET experiments and altered the allosteric modulation. The heterodimer model provided insights into the structural basis of allosteric modulation and the technique developed to characterize the A2AR–D2R interface can be extended to study the many other G protein-coupled receptors that engage in heteroreceptor complexes.
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Affiliation(s)
| | - David Rodriguez
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Wilber Romero-Fernandez
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Jon Kapla
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Mariama Jaiteh
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Anirudh Ranganathan
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Tzvetana Lazarova
- Department of Biochemistry and Molecular Biology, Institute of Neuroscience, Faculty of Medicine, Autonomous University of Barcelona, Barcelona, Spain
| | - Kjell Fuxe
- Department of Neuroscience, Karolinska Institute, Stockholm, Sweden
| | - Jens Carlsson
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
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21
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Guidolin D, Marcoli M, Tortorella C, Maura G, Agnati LF. G protein-coupled receptor-receptor interactions give integrative dynamics to intercellular communication. Rev Neurosci 2018; 29:703-726. [DOI: 10.1515/revneuro-2017-0087] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 01/01/2018] [Indexed: 01/14/2023]
Abstract
Abstract
The proposal of receptor-receptor interactions (RRIs) in the early 1980s broadened the view on the role of G protein-coupled receptors (GPCR) in the dynamics of the intercellular communication. RRIs, indeed, allow GPCR to operate not only as monomers but also as receptor complexes, in which the integration of the incoming signals depends on the number, spatial arrangement, and order of activation of the protomers forming the complex. The main biochemical mechanisms controlling the functional interplay of GPCR in the receptor complexes are direct allosteric interactions between protomer domains. The formation of these macromolecular assemblies has several physiologic implications in terms of the modulation of the signaling pathways and interaction with other membrane proteins. It also impacts on the emerging field of connectomics, as it contributes to set and tune the synaptic strength. Furthermore, recent evidence suggests that the transfer of GPCR and GPCR complexes between cells via the exosome pathway could enable the target cells to recognize/decode transmitters and/or modulators for which they did not express the pertinent receptors. Thus, this process may also open the possibility of a new type of redeployment of neural circuits. The fundamental aspects of GPCR complex formation and function are the focus of the present review article.
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Affiliation(s)
- Diego Guidolin
- Department of Neuroscience , University of Padova, via Gabelli 65 , I-35121 Padova , Italy
| | - Manuela Marcoli
- Department of Pharmacy and Center of Excellence for Biomedical Research , University of Genova , I-16126 Genova , Italy
| | - Cinzia Tortorella
- Department of Neuroscience , University of Padova, via Gabelli 65 , I-35121 Padova , Italy
| | - Guido Maura
- Department of Pharmacy and Center of Excellence for Biomedical Research , University of Genova , I-16126 Genova , Italy
| | - Luigi F. Agnati
- Department of Biomedical Sciences , University of Modena and Reggio Emilia , I-41121 Modena , Italy
- Department of Neuroscience , Karolinska Institutet , S-17177 Stockholm , Sweden
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22
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Oishi A, Cecon E, Jockers R. Melatonin Receptor Signaling: Impact of Receptor Oligomerization on Receptor Function. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 338:59-77. [DOI: 10.1016/bs.ircmb.2018.02.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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23
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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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24
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Uddin MS, Naider F, Becker JM. Dynamic roles for the N-terminus of the yeast G protein-coupled receptor Ste2p. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:2058-2067. [PMID: 28754538 DOI: 10.1016/j.bbamem.2017.07.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 07/13/2017] [Accepted: 07/24/2017] [Indexed: 12/11/2022]
Abstract
The Saccharomyces cerevisiae α-factor receptor Ste2p has been used extensively as a model to understand the molecular mechanism of signal transduction by G protein-coupled receptors (GPCRs). Single and double cysteine mutants of Ste2p were created and served as surrogates to detect intramolecular interactions and dimerization of Ste2p using disulfide cross-linking methodology. When a mutation was introduced into the phylogenetically conserved tyrosine residue at position 26 (Y26C) in the N-terminus of Ste2p, dimerization was increased greatly. The amount of dimer formed by this Y26C mutant was greatly reduced by ligand binding even though the ligand binding site is far removed from the N-terminus; the lowering of the dimer formation was consistent with a conformational change in the N-terminus of the receptor upon activation. Dimerization was decreased by double mutations Y26C/V109C or Y26C/T114C indicating that Y26 is in close proximity to V109 and T114 of extracellular loop 1 in native Ste2p. Combined with earlier studies, these results indicate previously unrecognized roles for the N-terminus of Ste2p, and perhaps of GPCRs in general, and reveal a specific N-terminus residue or region, that is involved in GPCR signaling, intrareceptor interactions, and receptor dimerization.
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Affiliation(s)
- M Seraj Uddin
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Fred Naider
- Department of Chemistry and Macromolecular Assemblies Institute, College of Staten Island, CUNY, New York, New York 10314, United States; Ph.D. Programs in Biochemistry and Chemistry, The Graduate Center of the City University of New York, New York, NY 10016, United States
| | - Jeffrey M Becker
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee 37996, United States.
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25
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Cevheroğlu O, Kumaş G, Hauser M, Becker JM, Son ÇD. The yeast Ste2p G protein-coupled receptor dimerizes on the cell plasma membrane. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:698-711. [PMID: 28073700 DOI: 10.1016/j.bbamem.2017.01.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 12/23/2016] [Accepted: 01/05/2017] [Indexed: 12/17/2022]
Abstract
Dimerization of G protein-coupled receptors (GPCR) may play an important role in maturation, internalization, signaling and/or pharmacology of these receptors. However, the location where dimerization occurs is still under debate. In our study, variants of Ste2p, a yeast mating pheromone GPCR, were tagged with split EGFP (enhanced green fluorescent protein) fragments inserted between transmembrane domain seven and the C-terminus or appended to the C-terminus. Bimolecular Fluorescence Complementation (BiFC) assay was used to determine where receptor dimerization occurred during protein trafficking by monitoring generation of EGFP fluorescence, which occurred upon GPCR dimerization. Our results suggest that these tagged receptors traffic to the membrane as monomers, undergo dimerization or higher ordered oligomerization predominantly on the plasma membrane, and are internalized as dimers/oligomers. This study is the first to provide direct in vivo visualization of GPCR dimerization/oligomerization, during trafficking to and from the plasma membrane.
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Affiliation(s)
- Orkun Cevheroğlu
- Department of Biological Sciences, Middle East Technical University, Universiteler Mah. Dumlupinar Blv. No: 1, 06800 Cankaya, Ankara, Turkey; Department of Microbiology, University of Tennessee, Knoxville, TN 37996, United States
| | - Gözde Kumaş
- Department of Biological Sciences, Middle East Technical University, Universiteler Mah. Dumlupinar Blv. No: 1, 06800 Cankaya, Ankara, Turkey
| | - Melinda Hauser
- Department of Microbiology, University of Tennessee, Knoxville, TN 37996, United States
| | - Jeffrey M Becker
- Department of Microbiology, University of Tennessee, Knoxville, TN 37996, United States
| | - Çağdaş D Son
- Department of Biological Sciences, Middle East Technical University, Universiteler Mah. Dumlupinar Blv. No: 1, 06800 Cankaya, Ankara, Turkey.
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26
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Huang Y, Sumida M, Kumazoe M, Sugihara K, Suemasu Y, Yamada S, Yamashita S, Miyakawa J, Takahashi T, Tanaka H, Fujimura Y, Tachibana H. Oligomer formation of a tea polyphenol, EGCG, on its sensing molecule 67 kDa laminin receptor. Chem Commun (Camb) 2017; 53:1941-1944. [DOI: 10.1039/c6cc09504f] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Green tea polyphenol (−)-epigallocatechin-3-O-gallate (EGCG) has been attributed to the activation of its cell surface sensing receptor 67 kDa laminin receptor (67LR).
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27
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Stoneman MR, Paprocki JD, Biener G, Yokoi K, Shevade A, Kuchin S, Raicu V. Quaternary structure of the yeast pheromone receptor Ste2 in living cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1859:1456-1464. [PMID: 27993568 DOI: 10.1016/j.bbamem.2016.12.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 12/05/2016] [Accepted: 12/08/2016] [Indexed: 12/15/2022]
Abstract
Transmembrane proteins known as G protein-coupled receptors (GPCRs) have been shown to form functional homo- or hetero-oligomeric complexes, although agreement has been slow to emerge on whether homo-oligomerization plays functional roles. Here we introduce a platform to determine the identity and abundance of differing quaternary structures formed by GPCRs in living cells following changes in environmental conditions, such as changes in concentrations. The method capitalizes on the intrinsic capability of FRET spectrometry to extract oligomer geometrical information from distributions of FRET efficiencies (or FRET spectrograms) determined from pixel-level imaging of cells, combined with the ability of the statistical ensemble approaches to FRET to probe the proportion of different quaternary structures (such as dimers, rhombus or parallelogram shaped tetramers, etc.) from averages over entire cells. Our approach revealed that the yeast pheromone receptor Ste2 forms predominantly tetramers at average expression levels of 2 to 25 molecules per pixel (2.8·10-6 to 3.5·10-5molecules/nm2), and a mixture of tetramers and octamers at expression levels of 25-100 molecules per pixel (3.5·10-5 to 1.4·10-4molecules/nm2). Ste2 is a class D GPCR found in the yeast Saccharomyces cerevisiae of the mating type a, and binds the pheromone α-factor secreted by cells of the mating type α. Such investigations may inform development of antifungal therapies targeting oligomers of pheromone receptors. The proposed FRET imaging platform may be used to determine the quaternary structure sub-states and stoichiometry of any GPCR and, indeed, any membrane protein in living cells. This article is part of a Special Issue entitled: Interactions between membrane receptors in cellular membranes edited by Kalina Hristova.
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Affiliation(s)
- Michael R Stoneman
- Physics Department, University of Wisconsin-Milwaukee, Milwaukee, WI, USA.
| | - Joel D Paprocki
- Physics Department, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Gabriel Biener
- Physics Department, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Koki Yokoi
- Physics Department, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Aishwarya Shevade
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Sergei Kuchin
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Valerică Raicu
- Physics Department, University of Wisconsin-Milwaukee, Milwaukee, WI, USA; Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, USA.
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Sridharan R, Connelly SM, Naider F, Dumont ME. Variable Dependence of Signaling Output on Agonist Occupancy of Ste2p, a G Protein-coupled Receptor in Yeast. J Biol Chem 2016; 291:24261-24279. [PMID: 27646004 DOI: 10.1074/jbc.m116.733006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Revised: 09/04/2016] [Indexed: 12/22/2022] Open
Abstract
We report here on the relationship between ligand binding and signaling responses in the yeast pheromone response pathway, a well characterized G protein-coupled receptor system. Responses to agonist (α-factor) by cells expressing widely varying numbers of receptors depend primarily on fractional occupancy, not the absolute number of agonist-bound receptors. Furthermore, the concentration of competitive antagonist required to inhibit α-factor-dependent signaling is more than 10-fold higher than predicted based on the known ligand affinities. Thus, responses to a particular number of agonist-bound receptors can vary greatly, depending on whether there are unoccupied or antagonist-bound receptors present on the same cell surface. This behavior does not appear to be due to pre-coupling of receptors to G protein or to the Sst2p regulator of G protein signaling. The results are consistent with a signaling response that is determined by the integration of positive signals from agonist-occupied receptors and inhibitory signals from unoccupied receptors, where the inhibitory signals can be diminished by antagonist binding.
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Affiliation(s)
- Rajashri Sridharan
- From the Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, New York 14642
| | - Sara M Connelly
- From the Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, New York 14642
| | - Fred Naider
- the Department of Chemistry and Macromolecular Assembly Institute, College of Staten Island of the City University of New York, Staten Island, New York 10314, and.,the Ph.D. Programs in Biochemistry and Chemistry, Graduate Center of the City University of New York, New York, New York 10016
| | - Mark E Dumont
- From the Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, New York 14642,
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Kleinau G, Müller A, Biebermann H. Oligomerization of GPCRs involved in endocrine regulation. J Mol Endocrinol 2016; 57:R59-80. [PMID: 27151573 DOI: 10.1530/jme-16-0049] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 05/04/2016] [Indexed: 12/27/2022]
Abstract
More than 800 different human membrane-spanning G-protein-coupled receptors (GPCRs) serve as signal transducers at biological barriers. These receptors are activated by a wide variety of ligands such as peptides, ions and hormones, and are able to activate a diverse set of intracellular signaling pathways. GPCRs are of central importance in endocrine regulation, which underpins the significance of comprehensively studying these receptors and interrelated systems. During the last decade, the capacity for multimerization of GPCRs was found to be a common and functionally relevant property. The interaction between GPCR monomers results in higher order complexes such as homomers (identical receptor subtype) or heteromers (different receptor subtypes), which may be present in a specific and dynamic monomer/oligomer equilibrium. It is widely accepted that the oligomerization of GPCRs is a mechanism for determining the fine-tuning and expansion of cellular processes by modification of ligand action, expression levels, and related signaling outcome. Accordingly, oligomerization provides exciting opportunities to optimize pharmacological treatment with respect to receptor target and tissue selectivity or for the development of diagnostic tools. On the other hand, GPCR heteromerization may be a potential reason for the undesired side effects of pharmacological interventions, faced with numerous and common mutual signaling modifications in heteromeric constellations. Finally, detailed deciphering of the physiological occurrence and relevance of specific GPCR/GPCR-ligand interactions poses a future challenge. This review will tackle the aspects of GPCR oligomerization with specific emphasis on family A GPCRs involved in endocrine regulation, whereby only a subset of these receptors will be discussed in detail.
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Affiliation(s)
- Gunnar Kleinau
- Institute of Experimental Pediatric Endocrinology (IEPE)Charité-Universitätsmedizin, Berlin, Germany
| | - Anne Müller
- Institute of Experimental Pediatric Endocrinology (IEPE)Charité-Universitätsmedizin, Berlin, Germany
| | - Heike Biebermann
- Institute of Experimental Pediatric Endocrinology (IEPE)Charité-Universitätsmedizin, Berlin, Germany
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30
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Tian H, Fürstenberg A, Huber T. Labeling and Single-Molecule Methods To Monitor G Protein-Coupled Receptor Dynamics. Chem Rev 2016; 117:186-245. [DOI: 10.1021/acs.chemrev.6b00084] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- He Tian
- Laboratory of Chemical Biology
and Signal Transduction, The Rockefeller University, 1230 York
Avenue, New York, New York 10065, United States
| | - Alexandre Fürstenberg
- Laboratory of Chemical Biology
and Signal Transduction, The Rockefeller University, 1230 York
Avenue, New York, New York 10065, United States
| | - Thomas Huber
- Laboratory of Chemical Biology
and Signal Transduction, The Rockefeller University, 1230 York
Avenue, New York, New York 10065, United States
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31
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Wnt/β-catenin signaling plays an ever-expanding role in stem cell self-renewal, tumorigenesis and cancer chemoresistance. Genes Dis 2016; 3:11-40. [PMID: 27077077 PMCID: PMC4827448 DOI: 10.1016/j.gendis.2015.12.004] [Citation(s) in RCA: 206] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Wnt signaling transduces evolutionarily conserved pathways which play important roles in initiating and regulating a diverse range of cellular activities, including cell proliferation, calcium homeostasis, and cell polarity. The role of Wnt signaling in controlling cell proliferation and stem cell self-renewal is primarily carried out through the canonical pathway, which is the best-characterized the multiple Wnt signaling branches. The past 10 years has seen a rapid expansion in our understanding of the complexity of this pathway, as many new components of Wnt signaling have been identified and linked to signaling regulation, stem cell functions, and adult tissue homeostasis. Additionally, a substantial body of evidence links Wnt signaling to tumorigenesis of cancer types and implicates it in the development of cancer drug resistance. Thus, a better understanding of the mechanisms by which dysregulation of Wnt signaling precedes the development and progression of human cancer may hasten the development of pathway inhibitors to augment current therapy. This review summarizes and synthesizes our current knowledge of the canonical Wnt pathway in development and disease. We begin with an overview of the components of the canonical Wnt signaling pathway and delve into the role this pathway has been shown to play in stemness, tumorigenesis, and cancer drug resistance. Ultimately, we hope to present an organized collection of evidence implicating Wnt signaling in tumorigenesis and chemoresistance to facilitate the pursuit of Wnt pathway modulators that may improve outcomes of cancers in which Wnt signaling contributes to aggressive disease and/or treatment resistance.
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Nomura W, Koseki T, Ohashi N, Mizuguchi T, Tamamura H. Trivalent ligands for CXCR4 bearing polyproline linkers show specific recognition for cells with increased CXCR4 expression. Org Biomol Chem 2015; 13:8734-9. [DOI: 10.1039/c5ob00891c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The trivalent ligand with rigid linkers designed for exploration of GPCR multimerization shows specific recognition for overexpressed CXCR4.
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Affiliation(s)
- Wataru Nomura
- Institute of Biomaterials and Bioengineering
- Tokyo Medical and Dental University
- Tokyo 101-0062
- Japan
| | - Taisuke Koseki
- Institute of Biomaterials and Bioengineering
- Tokyo Medical and Dental University
- Tokyo 101-0062
- Japan
| | - Nami Ohashi
- Institute of Biomaterials and Bioengineering
- Tokyo Medical and Dental University
- Tokyo 101-0062
- Japan
| | - Takaaki Mizuguchi
- Institute of Biomaterials and Bioengineering
- Tokyo Medical and Dental University
- Tokyo 101-0062
- Japan
| | - Hirokazu Tamamura
- Institute of Biomaterials and Bioengineering
- Tokyo Medical and Dental University
- Tokyo 101-0062
- Japan
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Guidolin D, Agnati LF, Marcoli M, Borroto-Escuela DO, Fuxe K. G-protein-coupled receptor type A heteromers as an emerging therapeutic target. Expert Opin Ther Targets 2014; 19:265-83. [PMID: 25381716 DOI: 10.1517/14728222.2014.981155] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION The discovery of receptor-receptor interactions (RRIs) in the early 1980s provided evidence that G-protein-coupled receptors (GPCRs) operate not only as monomers but also as heteromers, in which integration of the incoming signals takes place already at the plasma membrane level through allosteric RRIs. These integrative mechanisms give sophisticated dynamics to the structure and function of these receptor assemblies in terms of modulation of recognition, G-protein signaling and selectivity and switching to β-arrestin signaling. AREAS COVERED The present review briefly describes the concept of direct RRI and the available data on the mechanisms of oligomer formation. Further, pharmacological data concerning the best characterized heteromers involving type A GPCRs will be analyzed to evaluate their profile as possible targets for the treatment of various diseases, in particular of impacting diseases of the CNS. EXPERT OPINION GPCR heteromers have the potential to open a completely new field for pharmacology with likely a major impact in molecular medicine. Novel pharmacological strategies for the treatment of several pathologies have already been proposed. However, several challenges still exist to accurately characterize the role of the identified heteroreceptor complexes in pathology and to develop heteromer-specific ligands capable of efficiently exploiting their pharmacological features.
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Affiliation(s)
- Diego Guidolin
- University of Padova, Department of Molecular Medicine , via Gabelli 65, 35121 Padova , Italy +39 049 8272316 ; +39 049 8272319 ;
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35
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Kawada D, Kobayashi H, Tomita T, Nakata E, Nagano M, Siekhaus DE, Toshima JY, Toshima J. The yeast Arf-GAP Glo3p is required for the endocytic recycling of cell surface proteins. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1853:144-56. [PMID: 25409928 DOI: 10.1016/j.bbamcr.2014.10.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 10/09/2014] [Accepted: 10/10/2014] [Indexed: 11/26/2022]
Abstract
Small GTP-binding proteins of the Ras superfamily play diverse roles in intracellular trafficking. Among them, the Rab, Arf, and Rho families function in successive steps of vesicle transport, in forming vesicles from donor membranes, directing vesicle trafficking toward target membranes and docking vesicles onto target membranes. These proteins act as molecular switches that are controlled by a cycle of GTP binding and hydrolysis regulated by guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs). In this study we explored the role of GAPs in the regulation of the endocytic pathway using fluorescently labeled yeast mating pheromone α-factor. Among 25 non-essential GAP mutants, we found that deletion of the GLO3 gene, encoding Arf-GAP protein, caused defective internalization of fluorescently labeled α-factor. Quantitative analysis revealed that glo3Δ cells show defective α-factor binding to the cell surface. Interestingly, Ste2p, the α-factor receptor, was mis-localized from the plasma membrane to the vacuole in glo3Δ cells. Domain deletion mutants of Glo3p revealed that a GAP-independent function, as well as the GAP activity, of Glo3p is important for both α-factor binding and Ste2p localization at the cell surface. Additionally, we found that deletion of the GLO3 gene affects the size and number of Arf1p-residing Golgi compartments and causes a defect in transport from the TGN to the plasma membrane. Furthermore, we demonstrated that glo3Δ cells were defective in the late endosome-to-TGN transport pathway, but not in the early endosome-to-TGN transport pathway. These findings suggest novel roles for Arf-GAP Glo3p in endocytic recycling of cell surface proteins.
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Affiliation(s)
- Daiki Kawada
- Department of Biological Science and Technology, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585, Japan
| | - Hiromu Kobayashi
- Department of Biological Science and Technology, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585, Japan
| | - Tsuyoshi Tomita
- Department of Biological Science and Technology, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585, Japan
| | - Eisuke Nakata
- Department of Biological Science and Technology, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585, Japan
| | - Makoto Nagano
- Department of Biological Science and Technology, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585, Japan; Research Center for RNA Science, RIST, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585, Japan
| | | | - Junko Y Toshima
- Research Center for RNA Science, RIST, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585, Japan; Faculty of Science and Engineering, Waseda University, Wakamatsu-cho 2-2, Shinjuku-ku, Tokyo 162-8480, Japan.
| | - Jiro Toshima
- Department of Biological Science and Technology, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585, Japan; Research Center for RNA Science, RIST, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585, Japan.
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36
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Kawano K. [Stoichiometric analysis of oligomerization of membrane proteins using coiled-coil labeling and in-cell spectroscopy]. YAKUGAKU ZASSHI 2014; 134:931-7. [PMID: 25174363 DOI: 10.1248/yakushi.14-00162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Many membrane proteins are responsible for signaling and ionic transport necessary to maintain biological functions in vivo. Recently, not only conformational changes but also oligomerization have been proposed to regulate protein activation. Thus, the study of membrane protein oligomerization is crucial for new drug development. The existing destructive methodologies such as immunoprecipitation, however, are not suitable to determine oligomeric states precisely because of the artificial aggregation of proteins after detergent solubilization. In the present study, the coiled-coil tag-probe labeling method and spectral imaging were first combined to establish a new methodology based on fluorescence resonance energy transfer (FRET) for stoichiometric analysis of the oligomeric states of membrane proteins on living cells. After validating the method for mono-, di-, and tetrameric standard membrane proteins, the oligomeric state of β₂-adrenergic receptors (β₂ARs) was examined to clarify its functional significance. It was found that β2ARs could transduce cyclic adenosine 5'-monophosphate (cAMP) signals and internalize them upon treatment with ligands without showing any FRET signals. Thus, β₂ARs do not form constitutive homooligomers, and homooligomerization is not necessary for the receptor function of β₂ARs. Finally, the oligomeric state of full-length M2 proton-selective channels of influenza A virus was investigated. Although the results of X-ray crystallography and NMR studies using fragment peptides suggested that M2 stably forms a tetrameric channel, the full-length M2 proteins formed proton-conducting dimers at neutral pH and these dimers were converted to tetramers at acidic pH, indicating that the minimal functional unit of the M2 channel is a dimer.
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Affiliation(s)
- Kenichi Kawano
- Department of Biophysical Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University
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37
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Mizuno N, Suzuki T, Kishimoto Y, Hirasawa N. Biochemical assay of G protein-coupled receptor oligomerization: adenosine A1 and thromboxane A2 receptors form the novel functional hetero-oligomer. Methods Cell Biol 2014; 117:213-27. [PMID: 24143980 DOI: 10.1016/b978-0-12-408143-7.00012-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
G protein-coupled receptors (GPCRs) are classified into a family of seven transmembrane receptors. Receptor oligomerization may be the key to the expression and function of these receptors, for example, ligand binding, desensitization, membrane trafficking, and signaling. The accumulation of evidence that GPCRs form an oligomerization with a functional alternation may change the strategy for the discovery of novel drugs targeting GPCRs. Identification of the oligomer is essential to elucidate GPCR oligomerization. GPCR oligomerizations have been demonstrated using various biochemical approaches, which include the coimmunoprecipitation method, fluorescence resonance energy transfer assay, and bioluminescence RET assay. Thus, various assays are useful for the study of GPCR oligomerization, and we should choose the best method to match the purpose. We previously targeted adenosine A1 and thromboxane A2 (TP) receptors to form a functionally novel hetero-oligomer, since both receptors function in the same cells. This chapter describes the methods used to detect GPCR oligomerization and alterations in the signaling pathways, principally according to our findings on oligomerization between adenosine A1 and TPα receptors.
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MESH Headings
- Binding, Competitive
- Bioluminescence Resonance Energy Transfer Techniques/methods
- Cyclic AMP/metabolism
- Gene Expression
- Green Fluorescent Proteins/genetics
- Green Fluorescent Proteins/metabolism
- HEK293 Cells
- Humans
- Immunoprecipitation
- Kinetics
- Luciferases, Renilla/genetics
- Luciferases, Renilla/metabolism
- Mitogen-Activated Protein Kinase 1/genetics
- Mitogen-Activated Protein Kinase 1/metabolism
- Mitogen-Activated Protein Kinase 3/genetics
- Mitogen-Activated Protein Kinase 3/metabolism
- Plasmids
- Protein Binding
- Protein Multimerization
- Protein Transport
- Receptor, Adenosine A1/chemistry
- Receptor, Adenosine A1/genetics
- Receptor, Adenosine A1/metabolism
- Receptors, Thromboxane A2, Prostaglandin H2/chemistry
- Receptors, Thromboxane A2, Prostaglandin H2/genetics
- Receptors, Thromboxane A2, Prostaglandin H2/metabolism
- Signal Transduction
- Transfection
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Affiliation(s)
- Natsumi Mizuno
- Department of Pharmacotherapy of Life-style Related Disease, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
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38
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Borroto-Escuela DO, Brito I, Romero-Fernandez W, Di Palma M, Oflijan J, Skieterska K, Duchou J, Van Craenenbroeck K, Suárez-Boomgaard D, Rivera A, Guidolin D, Agnati LF, Fuxe K. The G protein-coupled receptor heterodimer network (GPCR-HetNet) and its hub components. Int J Mol Sci 2014; 15:8570-90. [PMID: 24830558 PMCID: PMC4057749 DOI: 10.3390/ijms15058570] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 03/26/2014] [Accepted: 04/30/2014] [Indexed: 01/09/2023] Open
Abstract
G protein-coupled receptors (GPCRs) oligomerization has emerged as a vital characteristic of receptor structure. Substantial experimental evidence supports the existence of GPCR-GPCR interactions in a coordinated and cooperative manner. However, despite the current development of experimental techniques for large-scale detection of GPCR heteromers, in order to understand their connectivity it is necessary to develop novel tools to study the global heteroreceptor networks. To provide insight into the overall topology of the GPCR heteromers and identify key players, a collective interaction network was constructed. Experimental interaction data for each of the individual human GPCR protomers was obtained manually from the STRING and SCOPUS databases. The interaction data were used to build and analyze the network using Cytoscape software. The network was treated as undirected throughout the study. It is comprised of 156 nodes, 260 edges and has a scale-free topology. Connectivity analysis reveals a significant dominance of intrafamily versus interfamily connections. Most of the receptors within the network are linked to each other by a small number of edges. DRD2, OPRM, ADRB2, AA2AR, AA1R, OPRK, OPRD and GHSR are identified as hubs. In a network representation 10 modules/clusters also appear as a highly interconnected group of nodes. Information on this GPCR network can improve our understanding of molecular integration. GPCR-HetNet has been implemented in Java and is freely available at http://www.iiia.csic.es/~ismel/GPCR-Nets/index.html.
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Affiliation(s)
| | - Ismel Brito
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, 17177 Stockholm, Sweden.
| | | | - Michael Di Palma
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, 17177 Stockholm, Sweden.
| | - Julia Oflijan
- Department of Physiology, Faculty of Medicine, University of Tartu, Tartu 50411, Estonia.
| | - Kamila Skieterska
- Laboratory of Eukaryotic Gene Expression and Signal Transduction (LEGEST), Ghent University, 9000 Ghent, Belgium.
| | - Jolien Duchou
- Laboratory of Eukaryotic Gene Expression and Signal Transduction (LEGEST), Ghent University, 9000 Ghent, Belgium.
| | - Kathleen Van Craenenbroeck
- Laboratory of Eukaryotic Gene Expression and Signal Transduction (LEGEST), Ghent University, 9000 Ghent, Belgium.
| | - Diana Suárez-Boomgaard
- Department of Cell Biology, School of Science, University of Málaga, 29071 Málaga, Spain.
| | - Alicia Rivera
- Department of Cell Biology, School of Science, University of Málaga, 29071 Málaga, Spain.
| | - Diego Guidolin
- Department of Molecular Medicine, University of Padova, Padova 35121, Italy.
| | - Luigi F Agnati
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, 17177 Stockholm, Sweden.
| | - Kjell Fuxe
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, 17177 Stockholm, Sweden.
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Chang CI, Schandel KA, Jenness DD. Interaction among Saccharomyces cerevisiae pheromone receptors during endocytosis. Biol Open 2014; 3:297-306. [PMID: 24682008 PMCID: PMC3988799 DOI: 10.1242/bio.20146866] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This study investigates endocytosis of Saccharomyces cerevisiae α-factor receptor and the role that receptor oligomerization plays in this process. α-factor receptor contains signal sequences in the cytoplasmic C-terminal domain that are essential for ligand-mediated endocytosis. In an endocytosis complementation assay, we found that oligomeric complexes of the receptor undergo ligand-mediated endocytosis when the α-factor binding site and the endocytosis signal sequences are located in different receptors. Both in vitro and in vivo assays suggested that ligand-induced conformational changes in one Ste2 subunit do not affect neighboring subunits. Therefore, recognition of the endocytosis signal sequence and recognition of the ligand-induced conformational change are likely to be two independent events.
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Affiliation(s)
- Chien-I Chang
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655, USA
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40
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Ghosh A, Sonavane U, Joshi R. Multiscale modelling to understand the self-assembly mechanism of human β2-adrenergic receptor in lipid bilayer. Comput Biol Chem 2014; 48:29-39. [DOI: 10.1016/j.compbiolchem.2013.11.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 11/06/2013] [Accepted: 11/07/2013] [Indexed: 11/27/2022]
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41
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De-la-Rosa V, Rangel-Yescas GE, Ladrón-de-Guevara E, Rosenbaum T, Islas LD. Coarse architecture of the transient receptor potential vanilloid 1 (TRPV1) ion channel determined by fluorescence resonance energy transfer. J Biol Chem 2013; 288:29506-17. [PMID: 23965996 DOI: 10.1074/jbc.m113.479618] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The transient receptor potential vanilloid 1 ion channel is responsible for the perception of high temperatures and low extracellular pH, and it is also involved in the response to some pungent compounds. Importantly, it is also associated with the perception of pain and noxious stimuli. Here, we attempt to discern the molecular organization and location of the N and C termini of the transient receptor potential vanilloid 1 ion channel by measuring FRET between genetically attached enhanced yellow and cyan fluorescent protein to the N or C terminus of the channel protein, expressed in transfected HEK 293 cells or Xenopus laevis oocytes. The static measurements of the domain organization were mapped into an available cryo-electron microscopy density of the channel with good agreement. These measurements also provide novel insights into the organization of terminal domains and their proximity to the plasma membrane.
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42
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Nakamura Y, Ishii J, Kondo A. Rapid, Facile Detection of Heterodimer Partners for Target Human G-Protein-Coupled Receptors Using a Modified Split-Ubiquitin Membrane Yeast Two-Hybrid System. PLoS One 2013; 8:e66793. [PMID: 23805278 PMCID: PMC3689660 DOI: 10.1371/journal.pone.0066793] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 05/11/2013] [Indexed: 12/03/2022] Open
Abstract
Potentially immeasurable heterodimer combinations of human G-protein-coupled receptors (GPCRs) result in a great deal of physiological diversity and provide a new opportunity for drug discovery. However, due to the existence of numerous combinations, the sets of GPCR dimers are almost entirely unknown and thus their dominant roles are still poorly understood. Thus, the identification of GPCR dimer pairs has been a major challenge. Here, we established a specialized method to screen potential heterodimer partners of human GPCRs based on the split-ubiquitin membrane yeast two-hybrid system. We demonstrate that the mitogen-activated protein kinase (MAPK) signal-independent method can detect ligand-induced conformational changes and rapidly identify heterodimer partners for target GPCRs. Our data present the abilities to apply for the intermolecular mapping of interactions among GPCRs and to uncover potential GPCR targets for the development of new therapeutic agents.
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Affiliation(s)
- Yasuyuki Nakamura
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, Kobe, Japan
| | - Jun Ishii
- Organization of Advanced Science and Technology, Kobe University, Kobe, Japan
| | - Akihiko Kondo
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, Kobe, Japan
- * E-mail:
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43
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Sungkaworn T, Jiarpinitnun C, Chaiyakunvat P, Chatsudthipong V. Bivalent angiotensin II suppresses oxidative stress-induced hyper-responsiveness of angiotensin II receptor type I. Eur J Med Chem 2013; 63:629-34. [DOI: 10.1016/j.ejmech.2013.02.041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 01/07/2013] [Accepted: 02/25/2013] [Indexed: 11/16/2022]
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Kawano K, Yano Y, Omae K, Matsuzaki S, Matsuzaki K. Stoichiometric analysis of oligomerization of membrane proteins on living cells using coiled-coil labeling and spectral imaging. Anal Chem 2013; 85:3454-61. [PMID: 23427815 DOI: 10.1021/ac400177a] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Many membrane proteins are proposed to work as oligomers; however, the conclusion is sometimes controversial, as for β2-adorenergic receptor (β2AR), which is one of the best-studied family A G-protein-coupled receptors. This is due to the lack of methods for easy and precise detection of the oligomeric state of membrane proteins on living cells. Here, we show that a combination of the coiled-coil tag-probe labeling method and spectral imaging enable a stoichiometric analysis of the oligomeric state of membrane proteins on living cells using monomeric, dimeric, and tetrameric standard membrane proteins. Using this method, we found that β2ARs do not form constitutive homooligomers, while they exhibit their functions such as the cyclic adenosine 5'-monophosphate (cAMP) signaling and internalization upon agonist stimulation.
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Affiliation(s)
- Kenichi Kawano
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto, Japan
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Rivero-Müller A, Jonas KC, Hanyaloglu AC, Huhtaniemi I. Di/Oligomerization of GPCRs—Mechanisms and Functional Significance. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 117:163-85. [DOI: 10.1016/b978-0-12-386931-9.00007-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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von Zastrow M, Williams JT. Modulating neuromodulation by receptor membrane traffic in the endocytic pathway. Neuron 2012; 76:22-32. [PMID: 23040804 DOI: 10.1016/j.neuron.2012.09.022] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Cellular responsiveness to many neuromodulators is controlled by endocytosis of the transmembrane receptors that transduce their effects. Endocytic membrane trafficking of particular neuromodulator receptors exhibits remarkable diversity and specificity, determined largely by molecular sorting operations that guide receptors at trafficking branchpoints after endocytosis. In this Review, we discuss recent progress in elucidating mechanisms mediating the molecular sorting of neuromodulator receptors in the endocytic pathway. There is emerging evidence that endocytic trafficking of neuromodulator receptors, in addition to influencing longer-term cellular responsiveness under conditions of prolonged or repeated activation, may also affect the acute response. Physiological and pathological consequences of defined receptor trafficking events are only now being elucidated, but it is already apparent that endocytosis of neuromodulator receptors has a significant impact on the actions of therapeutic drugs. The present data also suggest, conversely, that mechanisms of receptor endocytosis and molecular sorting may themselves represent promising targets for therapeutic manipulation.
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Affiliation(s)
- Mark von Zastrow
- Department of Psychiatry, University of California at San Francisco, San Francisco, CA 94158, USA.
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Functional and physical interactions among Saccharomyces cerevisiae α-factor receptors. EUKARYOTIC CELL 2012; 11:1276-88. [PMID: 22923047 DOI: 10.1128/ec.00172-12] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The α-factor receptor Ste2p is a G protein-coupled receptor (GPCR) expressed on the surface of MATa haploid cells of the yeast Saccharomyces cerevisiae. Binding of α-factor to Ste2p results in activation of a heterotrimeric G protein and of the pheromone response pathway. Functional interactions between α-factor receptors, such as dominant-negative effects and recessive behavior of constitutive and hypersensitive mutant receptors, have been reported previously. We show here that dominant-negative effects of mutant receptors persist over a wide range of ratios of the abundances of G protein to receptor and that such effects are not blocked by covalent fusion of G protein α subunits to normal receptors. In addition, we detected dominant effects of mutant C-terminally truncated receptors, which had not been previously reported to act in a dominant manner. Furthermore, coexpression of C-terminally truncated receptors with constitutively active mutant receptors results in enhancement of constitutive signaling. Together with previous evidence for oligomerization of Ste2p receptors, these results are consistent with the idea that functional interactions between coexpressed receptors arise from physical interactions between them rather than from competition for limiting downstream components, such as G proteins.
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Shivnaraine RV, Huang XP, Seidenberg M, Ellis J, Wells JW. Heterotropic cooperativity within and between protomers of an oligomeric M(2) muscarinic receptor. Biochemistry 2012; 51:4518-40. [PMID: 22551249 DOI: 10.1021/bi3000287] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
At least four allosteric sites have been found to mediate the dose-dependent effects of gallamine on the binding of [(3)H]quinuclidinylbenzilate (QNB) and N-[(3)H]methylscopolamine (NMS) to M(2) muscarinic receptors in membranes and solubilized preparations from porcine atria, CHO cells, and Sf9 cells. The rate of dissociation of [(3)H]QNB was affected in a bell-shaped manner with at least one Hill coefficient (n(H)) greater than 1, indicating that at least three allosteric sites are involved. The level of binding of [(3)H]QNB was decreased in a biphasic manner, revealing at least two allosteric sites; binding of [(3)H]NMS was affected in a triphasic, serpentine manner, revealing at least three sites, and values of n(H) >1 pointed to at least four sites. Several lines of evidence indicate that all effects of gallamine were allosteric in nature and could be observed at equilibrium. The rates of equilibration and dissociation suggest that the receptor was predominately oligomeric, and the heterogeneity revealed by gallamine can be attributed to differences in its affinity for the constituent protomers of a tetramer. Those differences appear to arise from inter- and intramolecular cooperativity between gallamine and the radioligand.
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Affiliation(s)
- Rabindra V Shivnaraine
- Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada M5S 3M2
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Goddard AD, Watts A. Contributions of fluorescence techniques to understanding G protein-coupled receptor dimerisation. Biophys Rev 2012; 4:291-298. [PMID: 28510206 DOI: 10.1007/s12551-012-0073-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Accepted: 03/13/2012] [Indexed: 12/27/2022] Open
Abstract
G protein-coupled receptors (GPCRs) are the largest class of eukaryotic cell-surface receptors and, over the last decade, it has become clear that they are capable of dimerisation. Whilst many biochemical and biophysical approaches have been used to study dimerisation, fluorescence techniques, including Förster resonance energy transfer and single molecule fluorescence, have been key players. Here we review recent contributions of fluorescence techniques to investigate GPCR dimers, including dimerisation in cell membranes and native tissues, the effect of ligand binding on dimerisation and the kinetics of dimer formation and dissociation. The challenges of studying multicomponent membrane protein systems have led to the development and refinement of many fluorescence assays, allowing the functional consequences of receptor dimerisation to be investigated and individual protein molecules to be imaged in the membranes of living cells. It is likely that the fluorescence techniques described here will be of use for investigating many other multicomponent membrane protein systems.
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Affiliation(s)
- Alan D Goddard
- Biomembrane Structure Unit, Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Anthony Watts
- Biomembrane Structure Unit, Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK.
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Feng C, Stamatos NM, Dragan AI, Medvedev A, Whitford M, Zhang L, Song C, Rallabhandi P, Cole L, Nhu QM, Vogel SN, Geddes CD, Cross AS. Sialyl residues modulate LPS-mediated signaling through the Toll-like receptor 4 complex. PLoS One 2012; 7:e32359. [PMID: 22496731 PMCID: PMC3322133 DOI: 10.1371/journal.pone.0032359] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 01/26/2012] [Indexed: 11/19/2022] Open
Abstract
We previously reported that neuraminidase (NA) pretreatment of human PBMCs markedly increased their cytokine response to lipopolysaccharide (LPS). To study the mechanisms by which this occurs, we transfected HEK293T cells with plasmids encoding TLR4, CD14, and MD2 (three components of the LPS receptor complex), as well as a NFκB luciferase reporting system. Both TLR4 and MD2 encoded by the plasmids are α-2,6 sialylated. HEK293T cells transfected with TLR4/MD2/CD14 responded robustly to the addition of LPS; however, omission of the MD2 plasmid abrogated this response. Addition of culture supernatants from MD2 (sMD2)-transfected HEK293T cells, but not recombinant, non-glycosylated MD2 reconstituted this response. NA treatment of sMD2 enhanced the LPS response as did NA treatment of the TLR4/CD14-transfected cell supplemented with untreated sMD2, but optimal LPS-initiated responses were observed with NA-treated TLR4/CD14-transfected cells supplemented with NA-treated sMD2. We hypothesized that removal of negatively charged sialyl residues from glycans on the TLR4 complex would hasten the dimerization of TLR4 monomers required for signaling. Co-transfection of HEK293T cells with separate plasmids encoding either YFP- or FLAG-tagged TLR4, followed by treatment with NA and stimulation with LPS, led to an earlier and more robust time-dependent dimerization of TLR4 monomers on co-immunoprecipitation, compared to untreated cells. These findings were confirmed by fluorescence resonance energy transfer (FRET) analysis. Overexpression of human Neu1 increased LPS-initiated TLR4-mediated NFκB activation and a NA inhibitor suppressed its activation. We conclude that (1) sialyl residues on TLR4 modulate LPS responsiveness, perhaps by facilitating clustering of the homodimers, and that (2) sialic acid, and perhaps other glycosyl species, regulate MD2 activity required for LPS-mediated signaling. We speculate that endogenous sialidase activity mobilized during cell activation may play a role in this regulation.
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Affiliation(s)
- Chiguang Feng
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Nicholas M. Stamatos
- Institute of Human Virology and Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Anatoliy I. Dragan
- Institute of Fluorescence, University of Maryland, Baltimore County, Baltimore, Maryland, United States of America
| | - Andrei Medvedev
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Melissa Whitford
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Lei Zhang
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Chang Song
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Prasad Rallabhandi
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Leah Cole
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Quan M. Nhu
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Stefanie N. Vogel
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Chris D. Geddes
- Institute of Fluorescence, University of Maryland, Baltimore County, Baltimore, Maryland, United States of America
| | - Alan S. Cross
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
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