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Lewis TR, Shores CR, Cady MA, Hao Y, Arshavsky VY, Burns ME. The F220C and F45L rhodopsin mutations identified in retinitis pigmentosa patients do not cause pathology in mice. Sci Rep 2020; 10:7538. [PMID: 32371886 PMCID: PMC7200662 DOI: 10.1038/s41598-020-64437-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 03/18/2020] [Indexed: 11/12/2022] Open
Abstract
Retinitis pigmentosa is a retinal degenerative disease that leads to blindness through photoreceptor loss. Rhodopsin is the most frequently mutated protein in this disease. While many rhodopsin mutations have well-understood consequences that lead to cell death, the disease association of several rhodopsin mutations identified in retinitis pigmentosa patients, including F220C and F45L, has been disputed. In this study, we generated two knockin mouse lines bearing each of these mutations. We did not observe any photoreceptor degeneration in either heterozygous or homozygous animals of either line. F220C mice exhibited minor disruptions of photoreceptor outer segment dimensions without any mislocalization of outer segment proteins, whereas photoreceptors of F45L mice were normal. Suction electrode recordings from individual photoreceptors of both mutant lines showed normal flash sensitivity and photoresponse kinetics. Taken together, these data suggest that neither the F220C nor F45L mutation has pathological consequences in mice and, therefore, may not be causative of retinitis pigmentosa in humans.
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Affiliation(s)
- Tylor R Lewis
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, 27710, United States
| | - Camilla R Shores
- Department of Cell Biology and Human Anatomy, University of California, Davis, CA, 95616, United States
| | - Martha A Cady
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, 27710, United States
| | - Ying Hao
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, 27710, United States
| | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, 27710, United States.,Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, 27710, United States
| | - Marie E Burns
- Department of Cell Biology and Human Anatomy, University of California, Davis, CA, 95616, United States. .,Center for Neuroscience and Department of Ophthalmology & Vision Science, University of California, Davis, CA, 95616, United States.
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2
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Thompson MD, Sakurai T, Rainero I, Maj MC, Kukkonen JP. Orexin Receptor Multimerization versus Functional Interactions: Neuropharmacological Implications for Opioid and Cannabinoid Signalling and Pharmacogenetics. Pharmaceuticals (Basel) 2017; 10:ph10040079. [PMID: 28991183 PMCID: PMC5748636 DOI: 10.3390/ph10040079] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 09/29/2017] [Accepted: 09/29/2017] [Indexed: 12/17/2022] Open
Abstract
Orexins/hypocretins are neuropeptides formed by proteolytic cleavage of a precursor peptide, which are produced by neurons found in the lateral hypothalamus. The G protein-coupled receptors (GPCRs) for these ligands, the OX₁ and OX₂ orexin receptors, are more widely expressed throughout the central nervous system. The orexin/hypocretin system has been implicated in many pathways, and its dysregulation is under investigation in a number of diseases. Disorders in which orexinergic mechanisms are being investigated include narcolepsy, idiopathic sleep disorders, cluster headache and migraine. Human narcolepsy has been associated with orexin deficiency; however, it has only rarely been attributed to mutations in the gene encoding the precursor peptide. While gene variations within the canine OX₂ gene hcrtr2 have been directly linked with narcolepsy, the majority of human orexin receptor variants are weakly associated with diseases (the idiopathic sleep disorders, cluster headache and polydipsia-hyponatremia in schizophrenia) or are of potential pharmacogenetic significance. Evidence for functional interactions and/or heterodimerization between wild-type and variant orexin receptors and opioid and cannabinoid receptors is discussed in the context of its relevance to depression and epilepsy.
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Affiliation(s)
- Miles D Thompson
- Department of Pediatrics, University of California, San Diego 92093, CA, USA.
| | - Takeshi Sakurai
- Department of Molecular Neuroscience and Integrative Physiology, Faculty of Medicine, Kanazawa University, Kanazawa 920-8620, Japan.
| | - Innocenzo Rainero
- Department of Neuroscience, University of Turin, Torino 10124, Italy.
| | - Mary C Maj
- Department of Biochemistry, School of Medicine, Saint George's University, Saint George's 11739, Grenada.
| | - Jyrki P Kukkonen
- Biochemistry and Cell Biology, Department of Veterinary Biosciences, University of Helsinki, Helsinki 11739, Finland.
- Department of Physiology, Institute of Biomedicine, Biomedicum Helsinki, University of Helsinki, Helsinki 00100, Finland.
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3
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Castelli MP, Spiga S, Perra A, Madeddu C, Mulas G, Ennas MG, Gessa GL. α2A adrenergic receptors highly expressed in mesoprefrontal dopamine neurons. Neuroscience 2016; 332:130-9. [PMID: 27365174 DOI: 10.1016/j.neuroscience.2016.06.037] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 06/20/2016] [Accepted: 06/22/2016] [Indexed: 12/21/2022]
Abstract
α2 adrenoreceptors (α2-ARs) play a key role in the control of noradrenaline and dopamine release in the medial prefrontal cortex (mPFC). Here, using UV-laser microdissection-based quantitative mRNA expression in individual neurons we show that in hTH-GFP rats, a transgenic line exhibiting intense and specific fluorescence in dopaminergic (DA) neurons, α2A adrenoreceptor (α2A-AR) mRNA is expressed at high and low levels in DA cells in the ventral tegmental area (VTA) and substantia nigra compacta (SNc), respectively. Confocal microscopy fluorescence immunohistochemistry revealed that α2A-AR immunoreactivity colocalized with tyrosine hydroxylase (TH) in nearly all DA cells in the VTA and SNc, both in hTH-GFP rats and their wild-type Sprague-Dawley (SD) counterparts. α2A-AR immunoreactivity was also found in DA axonal projections to the mPFC and dorsal caudate in the hTH-GFP and in the anterogradely labeled DA axonal projections from VTA to mPFC in SD rats. Importantly, the α2A-AR immunoreactivity localized in the DA cells of VTA and in their fibers in the mPFC was much higher than that in DA cells of SNc and their fibers in dorsal caudate, respectively. The finding that α2A-ARs are highly expressed in the cell bodies and axons of mesoprefrontal dopaminergic neurons provides a morphological basis to the vast functional evidence that somatodendritic and nerve-terminal α2A-AR receptors control dopaminergic activity and dopamine release in the prefrontal cortex. This finding raises the question whether α2A-ARs might function as autoreceptors in the mesoprefrontal dopaminergic neurons, replacing the lack of D2 autoreceptors.
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Affiliation(s)
- M Paola Castelli
- Department of Biomedical Sciences, University of Cagliari, 09042 Monserrato, Italy; Center of Excellence "Neurobiology of Addiction", University of Cagliari, 09042 Monserrato, Italy.
| | - Saturnino Spiga
- Department of Life and Environmental Sciences, University of Cagliari, 09126 Cagliari, Italy
| | - Andrea Perra
- Department of Biomedical Sciences, University of Cagliari, 09042 Monserrato, Italy
| | - Camilla Madeddu
- Department of Biomedical Sciences, University of Cagliari, 09042 Monserrato, Italy
| | - Giovanna Mulas
- Department of Life and Environmental Sciences, University of Cagliari, 09126 Cagliari, Italy
| | - M Grazia Ennas
- Department of Biomedical Sciences, University of Cagliari, 09042 Monserrato, Italy
| | - Gian Luigi Gessa
- Department of Biomedical Sciences, University of Cagliari, 09042 Monserrato, Italy; Guy Everett Laboratory" University of Cagliari, 09042 Monserrato, Italy
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4
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Evans AE, Tripathi A, LaPorte HM, Brueggemann LI, Singh AK, Albee LJ, Byron KL, Tarasova NI, Volkman BF, Cho TY, Gaponenko V, Majetschak M. New Insights into Mechanisms and Functions of Chemokine (C-X-C Motif) Receptor 4 Heteromerization in Vascular Smooth Muscle. Int J Mol Sci 2016; 17:ijms17060971. [PMID: 27331810 PMCID: PMC4926503 DOI: 10.3390/ijms17060971] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 06/07/2016] [Accepted: 06/13/2016] [Indexed: 12/14/2022] Open
Abstract
Recent evidence suggests that C-X-C chemokine receptor type 4 (CXCR4) heteromerizes with α1A/B-adrenoceptors (AR) and atypical chemokine receptor 3 (ACKR3) and that CXCR4:α1A/B-AR heteromers are important for α1-AR function in vascular smooth muscle cells (VSMC). Structural determinants for CXCR4 heteromerization and functional consequences of CXCR4:α1A/B-AR heteromerization in intact arteries, however, remain unknown. Utilizing proximity ligation assays (PLA) to visualize receptor interactions in VSMC, we show that peptide analogs of transmembrane-domain (TM) 2 and TM4 of CXCR4 selectively reduce PLA signals for CXCR4:α1A-AR and CXCR4:ACKR3 interactions, respectively. While both peptides inhibit CXCL12-induced chemotaxis, only the TM2 peptide inhibits phenylephrine-induced Ca2+-fluxes, contraction of VSMC and reduces efficacy of phenylephrine to constrict isolated arteries. In a Cre-loxP mouse model to delete CXCR4 in VSMC, we observed 60% knockdown of CXCR4. PLA signals for CXCR4:α1A/B-AR and CXCR4:ACKR3 interactions in VSMC, however, remained constant. Our observations point towards TM2/4 of CXCR4 as possible contact sites for heteromerization and suggest that TM-derived peptide analogs permit selective targeting of CXCR4 heteromers. A molecular dynamics simulation of a receptor complex in which the CXCR4 homodimer interacts with α1A-AR via TM2 and with ACKR3 via TM4 is presented. Our findings further imply that CXCR4:α1A-AR heteromers are important for intrinsic α1-AR function in intact arteries and provide initial and unexpected insights into the regulation of CXCR4 heteromerization in VSMC.
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MESH Headings
- Animals
- Binding Sites
- Calcium/metabolism
- Cell Line
- Cells, Cultured
- Female
- Humans
- Male
- Mice
- Molecular Dynamics Simulation
- Muscle, Smooth, Vascular/metabolism
- Protein Binding
- Protein Multimerization
- Rats
- Rats, Sprague-Dawley
- Receptors, Adrenergic, alpha-1/metabolism
- Receptors, CXCR/genetics
- Receptors, CXCR/metabolism
- Receptors, CXCR4/chemistry
- Receptors, CXCR4/genetics
- Receptors, CXCR4/metabolism
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Affiliation(s)
- Ann E Evans
- Burn and Shock Trauma Research Institute, Department of Surgery, Loyola University Chicago Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60153, USA.
| | - Abhishek Tripathi
- Burn and Shock Trauma Research Institute, Department of Surgery, Loyola University Chicago Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60153, USA.
| | - Heather M LaPorte
- Burn and Shock Trauma Research Institute, Department of Surgery, Loyola University Chicago Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60153, USA.
| | - Lioubov I Brueggemann
- Department of Molecular Pharmacology and Therapeutics, Loyola University Chicago Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60153, USA.
| | - Abhay Kumar Singh
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, 1100 South Grand Blvd., St. Louis, MO 63104, USA.
| | - Lauren J Albee
- Burn and Shock Trauma Research Institute, Department of Surgery, Loyola University Chicago Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60153, USA.
| | - Kenneth L Byron
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, 1100 South Grand Blvd., St. Louis, MO 63104, USA.
| | - Nadya I Tarasova
- Cancer and Inflammation Program, National Cancer Institute, PO Box B, Frederick, MD 21702-1201, USA.
| | - Brian F Volkman
- Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.
| | - Thomas Yoonsang Cho
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, 1100 South Grand Blvd., St. Louis, MO 63104, USA.
| | - Vadim Gaponenko
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, 900 S Ashland, Chicago, IL 60607, USA.
| | - Matthias Majetschak
- Burn and Shock Trauma Research Institute, Department of Surgery, Loyola University Chicago Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60153, USA.
- Department of Molecular Pharmacology and Therapeutics, Loyola University Chicago Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60153, USA.
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5
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Tripathi A, Vana PG, Chavan TS, Brueggemann LI, Byron KL, Tarasova NI, Volkman BF, Gaponenko V, Majetschak M. Heteromerization of chemokine (C-X-C motif) receptor 4 with α1A/B-adrenergic receptors controls α1-adrenergic receptor function. Proc Natl Acad Sci U S A 2015; 112:E1659-68. [PMID: 25775528 PMCID: PMC4386352 DOI: 10.1073/pnas.1417564112] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Recent evidence suggests that chemokine (C-X-C motif) receptor 4 (CXCR4) contributes to the regulation of blood pressure through interactions with α1-adrenergic receptors (ARs) in vascular smooth muscle. The underlying molecular mechanisms, however, are unknown. Using proximity ligation assays to visualize single-molecule interactions, we detected that α1A/B-ARs associate with CXCR4 on the cell surface of rat and human vascular smooth muscle cells (VSMC). Furthermore, α1A/B-AR could be coimmunoprecipitated with CXCR4 in a HeLa expression system and in human VSMC. A peptide derived from the second transmembrane helix of CXCR4 induced chemical shift changes in the NMR spectrum of CXCR4 in membranes, disturbed the association between α1A/B-AR and CXCR4, and inhibited Ca(2+) mobilization, myosin light chain (MLC) 2 phosphorylation, and contraction of VSMC upon α1-AR activation. CXCR4 silencing reduced α1A/B-AR:CXCR4 heteromeric complexes in VSMC and abolished phenylephrine-induced Ca(2+) fluxes and MLC2 phosphorylation. Treatment of rats with CXCR4 agonists (CXCL12, ubiquitin) reduced the EC50 of the phenylephrine-induced blood pressure response three- to fourfold. These observations suggest that disruption of the quaternary structure of α1A/B-AR:CXCR4 heteromeric complexes by targeting transmembrane helix 2 of CXCR4 and depletion of the heteromeric receptor complexes by CXCR4 knockdown inhibit α1-AR-mediated function in VSMC and that activation of CXCR4 enhances the potency of α1-AR agonists. Our findings extend the current understanding of the molecular mechanisms regulating α1-AR and provide an example of the importance of G protein-coupled receptor (GPCR) heteromerization for GPCR function. Compounds targeting the α1A/B-AR:CXCR4 interaction could provide an alternative pharmacological approach to modulate blood pressure.
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Affiliation(s)
- Abhishek Tripathi
- Burn and Shock Trauma Research Institute, Department of Surgery, Loyola University Chicago Stritch School of Medicine, Maywood, IL 60153
| | - P Geoff Vana
- Burn and Shock Trauma Research Institute, Department of Surgery, Loyola University Chicago Stritch School of Medicine, Maywood, IL 60153
| | - Tanmay S Chavan
- Department of Medicinal Chemistry, University of Illinois, Chicago, IL 60607
| | - Lioubov I Brueggemann
- Department of Molecular Pharmacology and Therapeutics, Loyola University Chicago Stritch School of Medicine, Maywood, IL 60153
| | - Kenneth L Byron
- Department of Molecular Pharmacology and Therapeutics, Loyola University Chicago Stritch School of Medicine, Maywood, IL 60153
| | - Nadya I Tarasova
- Cancer and Inflammation Program, National Cancer Institute, Frederick, MD 21702-1201
| | - Brian F Volkman
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226; and
| | - Vadim Gaponenko
- Department of Biochemistry and Molecular Genetics, University of Illinois, Chicago, IL 60607
| | - Matthias Majetschak
- Burn and Shock Trauma Research Institute, Department of Surgery, Loyola University Chicago Stritch School of Medicine, Maywood, IL 60153; Department of Molecular Pharmacology and Therapeutics, Loyola University Chicago Stritch School of Medicine, Maywood, IL 60153;
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6
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Filipeanu CM. Temperature-Sensitive Intracellular Traffic of α2C-Adrenergic Receptor. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 132:245-65. [DOI: 10.1016/bs.pmbts.2015.02.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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7
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Tehseen M, Liao C, Dacres H, Dumancic M, Trowell S, Anderson A. Oligomerisation of C. elegans olfactory receptors, ODR-10 and STR-112, in yeast. PLoS One 2014; 9:e108680. [PMID: 25254556 PMCID: PMC4177895 DOI: 10.1371/journal.pone.0108680] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 09/02/2014] [Indexed: 01/08/2023] Open
Abstract
It is widely accepted that vertebrate G-Protein Coupled Receptors (GPCRs) associate with each other as homo- or hetero-dimers or higher-order oligomers. The C. elegans genome encodes hundreds of olfactory GPCRs, which may be expressed in fewer than a dozen chemosensory neurons, suggesting an opportunity for oligomerisation. Here we show, using three independent lines of evidence: co-immunoprecipitation, bioluminescence resonance energy transfer and a yeast two-hybrid assay that nematode olfactory receptors (ORs) oligomerise when heterologously expressed in yeast. Specifically, the nematode receptor ODR-10 is able to homo-oligomerise and can also form heteromers with the related nematode receptor STR-112. ODR-10 also oligomerised with the rat I7 OR but did not oligomerise with the human somatostatin receptor 5, a neuropeptide receptor. In this study, the question of functional relevance was not addressed and remains to be investigated.
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Affiliation(s)
- Muhammad Tehseen
- CSIRO Food Futures National Research Flagship & CSIRO Ecosystem Sciences, Australia, Canberra, ACT, Australia
- Center for Desert Agriculture, Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
| | - Chunyan Liao
- CSIRO Food Futures National Research Flagship & CSIRO Ecosystem Sciences, Australia, Canberra, ACT, Australia
| | - Helen Dacres
- CSIRO Food Futures National Research Flagship & CSIRO Ecosystem Sciences, Australia, Canberra, ACT, Australia
| | - Mira Dumancic
- CSIRO Food Futures National Research Flagship & CSIRO Ecosystem Sciences, Australia, Canberra, ACT, Australia
| | - Stephen Trowell
- CSIRO Food Futures National Research Flagship & CSIRO Ecosystem Sciences, Australia, Canberra, ACT, Australia
| | - Alisha Anderson
- CSIRO Food Futures National Research Flagship & CSIRO Ecosystem Sciences, Australia, Canberra, ACT, Australia
- * E-mail:
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8
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The β-adrenergic system as a possible new target for pharmacologic treatment of neovascular retinal diseases. Prog Retin Eye Res 2014; 42:103-29. [DOI: 10.1016/j.preteyeres.2014.06.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 05/30/2014] [Accepted: 06/05/2014] [Indexed: 12/31/2022]
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9
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Wnorowski A, Jozwiak K. Homo- and hetero-oligomerization of β2-adrenergic receptor in receptor trafficking, signaling pathways and receptor pharmacology. Cell Signal 2014; 26:2259-65. [PMID: 25049076 DOI: 10.1016/j.cellsig.2014.06.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 06/27/2014] [Indexed: 10/25/2022]
Abstract
The β2-adrenergic receptor (β2AR) is the prototypic member of G protein-coupled receptors (GPCRs) involved in the production of physiological responses to adrenaline and noradrenaline. Research done in the past few years vastly demonstrated that β2AR can form homo- and hetero-oligomers. Despite the fact that currently this phenomenon is widely accepted, the spread and relevance of β2AR oligomerization are still a matter of debate. This review considers the progress achieved in the field of β2AR oligomerization with focus on the implications of the receptor-receptor interactions to β2AR trafficking, pharmacology and downstream signal transduction pathways.
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Affiliation(s)
- Artur Wnorowski
- Laboratory of Medicinal Chemistry and Neuroengineering, Department of Chemistry, Medical University of Lublin, 20-093 Lublin, Poland.
| | - Krzysztof Jozwiak
- Laboratory of Medicinal Chemistry and Neuroengineering, Department of Chemistry, Medical University of Lublin, 20-093 Lublin, Poland.
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10
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Jäntti MH, Mandrika I, Kukkonen JP. Human orexin/hypocretin receptors form constitutive homo- and heteromeric complexes with each other and with human CB1 cannabinoid receptors. Biochem Biophys Res Commun 2014; 445:486-90. [PMID: 24530395 DOI: 10.1016/j.bbrc.2014.02.026] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 02/06/2014] [Indexed: 12/17/2022]
Abstract
Human OX1 orexin receptors have been shown to homodimerize and they have also been suggested to heterodimerize with CB1 cannabinoid receptors. The latter has been suggested to be important for orexin receptor responses and trafficking. In this study, we wanted to assess the ability of the other combinations of receptors to also form similar complexes. Vectors for expression of human OX1, OX2 and CB1 receptors, C-terminally fused with either Renilla luciferase or GFP(2) green fluorescent protein variant, were generated. The constructs were transiently expressed in Chinese hamster ovary cells, and constitutive dimerization between the receptors was assessed by bioluminescence energy transfer (BRET). Orexin receptor subtypes readily formed homo- and hetero(di)mers, as suggested by significant BRET signals. CB1 receptors formed homodimers, and they also heterodimerized with both orexin receptors. Interestingly, BRET efficiency was higher for homodimers than for almost all heterodimers. This is likely to be due to the geometry of the interaction; the putatively symmetric dimers may place the C-termini in a more suitable orientation in homomers. Fusion of luciferase to an orexin receptor and GFP(2) to CB1 produced more effective BRET than the opposite fusions, also suggesting differences in geometry. Similar was seen for the OX1-OX2 interaction. In conclusion, orexin receptors have a significant propensity to make homo- and heterodi-/oligomeric complexes. However, it is unclear whether this affects their signaling. As orexin receptors efficiently signal via endocannabinoid production to CB1 receptors, dimerization could be an effective way of forming signal complexes with optimal cannabinoid concentrations available for cannabinoid receptors.
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Affiliation(s)
- Maria H Jäntti
- Department of Veterinary Biosciences, POB 66, FIN-00014 University of Helsinki, Finland.
| | - Ilona Mandrika
- Latvian Biomedical Research and Study Centre, Ratsupites Str. 1, Riga LV 1067, Latvia.
| | - Jyrki P Kukkonen
- Department of Veterinary Biosciences, POB 66, FIN-00014 University of Helsinki, Finland.
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11
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Cottingham C, Lu R, Jiao K, Wang Q. Cross-talk from β-adrenergic receptors modulates α2A-adrenergic receptor endocytosis in sympathetic neurons via protein kinase A and spinophilin. J Biol Chem 2013; 288:29193-205. [PMID: 23965992 DOI: 10.1074/jbc.m113.469494] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Inter-regulation of adrenergic receptors (ARs) via cross-talk is a long appreciated but mechanistically unclear physiological phenomenon. Evidence from the AR literature and our own extensive studies on regulation of α2AARs by the scaffolding protein spinophilin have illuminated a potential novel mechanism for cross-talk from β to α2ARs. In the present study, we have characterized a mode of endogenous AR cross-talk in native adrenergic neurons whereby canonical βAR-mediated signaling modulates spinophilin-regulated α2AAR endocytosis through PKA. Our findings demonstrate that co-activation of β and α2AARs, either by application of endogenous agonist or by simultaneous stimulation with distinct selective agonists, results in acceleration of endogenous α2AAR endocytosis in native neurons. We show that receptor-independent PKA activation by forskolin is sufficient to accelerate α2AAR endocytosis and that α2AAR stimulation alone drives accelerated endocytosis in spinophilin-null neurons. Endocytic response acceleration by β/α2AAR co-activation is blocked by PKA inhibition and lost in spinophilin-null neurons, consistent with our previous finding that spinophilin is a substrate for phosphorylation by PKA that disrupts its interaction with α2AARs. Importantly, we show that α2AR agonist-mediated α2AAR/spinophilin interaction is blocked by βAR co-activation in a PKA-dependent fashion. We therefore propose a novel mechanism for cross-talk from β to α2ARs, whereby canonical βAR-mediated signaling coupled to PKA activation results in phosphorylation of spinophilin, disrupting its interaction with α2AARs and accelerating α2AAR endocytic responses. This mechanism of cross-talk has significant implications for endogenous adrenergic physiology and for therapeutic targeting of β and α2AARs.
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12
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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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13
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Cotecchia S, Stanasila L, Diviani D. Protein-protein interactions at the adrenergic receptors. Curr Drug Targets 2012; 13:15-27. [PMID: 21777184 PMCID: PMC3290771 DOI: 10.2174/138945012798868489] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Revised: 02/12/2011] [Accepted: 02/16/2011] [Indexed: 01/07/2023]
Abstract
The adrenergic receptors are among the best characterized G protein-coupled receptors (GPCRs) and knowledge on this receptor family has provided several important paradigms about GPCR function and regulation. One of the most recent paradigms initially supported by studies on adrenergic receptors is that both βarrestins and G protein-coupled receptors themselves can act as scaffolds binding a variety of proteins and this can result in growing complexity of the receptor-mediated cellular effects. In this review we will briefly summarize the main features of βarrestin binding to the adrenergic receptor subtypes and we will review more in detail the main proteins found to selectively interact with distinct AR subtype. At the end, we will review the main findings on oligomerization of the AR subtypes.
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Affiliation(s)
- Susanna Cotecchia
- Départment de Pharmacologie et de Toxicologie, Université de Lausanne, Switzerland.
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14
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Wise H. The roles played by highly truncated splice variants of G protein-coupled receptors. J Mol Signal 2012; 7:13. [PMID: 22938630 PMCID: PMC3477067 DOI: 10.1186/1750-2187-7-13] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 07/29/2012] [Indexed: 01/08/2023] Open
Abstract
Alternative splicing of G protein-coupled receptor (GPCR) genes greatly increases the total number of receptor isoforms which may be expressed in a cell-dependent and time-dependent manner. This increased diversity of cell signaling options caused by the generation of splice variants is further enhanced by receptor dimerization. When alternative splicing generates highly truncated GPCRs with less than seven transmembrane (TM) domains, the predominant effect in vitro is that of a dominant-negative mutation associated with the retention of the wild-type receptor in the endoplasmic reticulum (ER). For constitutively active (agonist-independent) GPCRs, their attenuated expression on the cell surface, and consequent decreased basal activity due to the dominant-negative effect of truncated splice variants, has pathological consequences. Truncated splice variants may conversely offer protection from disease when expression of co-receptors for binding of infectious agents to cells is attenuated due to ER retention of the wild-type co-receptor. In this review, we will see that GPCRs retained in the ER can still be functionally active but also that highly truncated GPCRs may also be functionally active. Although rare, some truncated splice variants still bind ligand and activate cell signaling responses. More importantly, by forming heterodimers with full-length GPCRs, some truncated splice variants also provide opportunities to generate receptor complexes with unique pharmacological properties. So, instead of assuming that highly truncated GPCRs are associated with faulty transcription processes, it is time to reassess their potential benefit to the host organism.
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Affiliation(s)
- Helen Wise
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, SAR, China.
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15
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Somvanshi RK, Chaudhari N, Qiu X, Kumar U. Heterodimerization of β2 adrenergic receptor and somatostatin receptor 5: Implications in modulation of signaling pathway. J Mol Signal 2011; 6:9. [PMID: 21838893 PMCID: PMC3166894 DOI: 10.1186/1750-2187-6-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Accepted: 08/12/2011] [Indexed: 12/17/2022] Open
Abstract
Background In the present study, we describe heterodimerization between human-Somatostatin Receptor 5 (hSSTR5) and β2-Adrenergic Receptor (β2AR) and its impact on the receptor trafficking, coupling to adenylyl cyclase and signaling including mitogen activated protein kinases and calcineurin-NFAT pathways. Methods We used co-immunoprecipitation, photobleaching- fluorescence resonance energy transfer and Fluorescence assisted cell sorting analysis to characterize heterodimerization between SSTR5 and β2AR. Results Our results indicate that hSSTR5/β2AR exist as preformed heterodimers in the basal condition which is enhanced upon co-activation of both receptors. In contrast, the activation of individual receptors leads to the dissociation of heterodimers. Receptor coupling to adenylyl cyclase displayed predominant effect of β2AR, however, somatostatin mediated inhibition of cAMP was enhanced upon blocking β2AR. Our results indicate hSSTR5 mediated significant activation of ERK1/2 and inhibition of phospho-p38. The phospho-NFAT level was enhanced in cotransfected cells indicating the blockade of calcineurin mediated dephosphorylation of NFAT upon receptor heterodimerization. Conclusion These data for the first time unveil a novel insight for the role of hSSTR5/β2AR in the modulation of signaling pathways which has not been addressed earlier.
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Affiliation(s)
- Rishi K Somvanshi
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC, Canada.
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16
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Chotani MA, Flavahan NA. Intracellular α(2C)-adrenoceptors: storage depot, stunted development or signaling domain? BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2011; 1813:1495-503. [PMID: 21605601 DOI: 10.1016/j.bbamcr.2011.05.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Revised: 05/03/2011] [Accepted: 05/06/2011] [Indexed: 12/11/2022]
Abstract
G-protein coupled receptors (GPCRs) are generally considered to function as cell surface signaling structures that respond to extracellular mediators, many of which do not readily access the cell's interior. Indeed, most GPCRs are preferentially targeted to the plasma membrane. However, some receptors, including α(2C)-Adrenoceptors, challenge conventional concepts of GPCR activity by being preferentially retained and localized within intracellular organelles. This review will address the issues associated with this unusual GPCR localization and discuss whether it represents a novel sub-cellular niche for GPCR signaling, whether these receptors are being stored for rapid deployment to the cell surface, or whether they represent immature or incomplete receptor systems.
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Affiliation(s)
- Maqsood A Chotani
- Center for Cardiovascular and Pulmonary Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
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17
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Albizu L, Moreno JL, González-Maeso J, Sealfon SC. Heteromerization of G protein-coupled receptors: relevance to neurological disorders and neurotherapeutics. CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2011; 9:636-50. [PMID: 20632964 DOI: 10.2174/187152710793361586] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Accepted: 03/30/2010] [Indexed: 11/22/2022]
Abstract
Because G protein-coupled receptors (GPCRs) are numerous, widely expressed and involved in major physiological responses, they represent a relevant therapeutic target for drug discovery, particularly regarding pharmacological treatments of neurological disorders. Among the biological phenomena regulating receptor function, GPCR heteromerization is an important emerging area of interest and investigation. There is increasing evidence showing that heteromerization contributes to the pharmacological heterogeneity of GPCRs by modulating receptor ontogeny, activation and recycling. Although in many cases the physiological relevance of receptor heteromerization has not been fully established, the unique pharmacological and functional properties of heteromers are likely to lead to new strategies in clinical medicine. This review describes the main GPCR heteromers and their implications for major neurological disorders such as Parkinson's disease, schizophrenia and addiction. A better understanding of molecular mechanisms underlying drug interactions related to the targeting of receptor heteromers could provide more specific and efficient therapeutic agents for the treatment of brain diseases.
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Affiliation(s)
- Laura Albizu
- Department of Neurology, Mount Sinai School of Medicine, New York, NY 10029, USA
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18
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Watts SW. Endothelin receptors: what's new and what do we need to know? Am J Physiol Regul Integr Comp Physiol 2009; 298:R254-60. [PMID: 19907001 DOI: 10.1152/ajpregu.00584.2009] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Receptors are at the heart of how a molecule transmits a signal to a cell. Two receptor classes for endothelin (ET) are recognized, the ET(A) and ET(B) receptors. Intriguing questions have arisen in the field of ET receptor pharmacology, physiology, and function. For example, a host of pharmacological studies support the interaction of the ET(A) and ET(B) receptor in tissues (veins, arteries, bronchus, arterioles, esophagus), but yet few have been able to demonstrate direct ET(A)/ET(B) receptor interaction. Have we modeled this interaction wrong? Do we have a truly selective ET(A) receptor agonist such that we could selectively stimulate this important receptor? What can we learn from the recent phylogenic studies of the ET receptor family? Have we adequately addressed the number of biological molecules with which ET can interact to exert a biological effect? Recent mass spectrometry studies in our laboratory suggest that ET-1 interacts with other hereto unrecognized proteins. Biased ligands (ligands at the same receptor that elicit distinct signaling responses) have been discovered for other receptors. Do these exist for ET receptors and can we take advantage of this possibility in drug design? These and other questions will be posed in this minireview on topics on ET receptors.
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Affiliation(s)
- Stephanie W Watts
- Dept. of Pharmacology and Toxicology, B445 Life Sciences Bldg., East Lansing, MI 48824-1317, USA.
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19
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Navarro G, Aymerich MS, Marcellino D, Cortés A, Casadó V, Mallol J, Canela EI, Agnati L, Woods AS, Fuxe K, Lluís C, Lanciego JL, Ferré S, Franco R. Interactions between calmodulin, adenosine A2A, and dopamine D2 receptors. J Biol Chem 2009; 284:28058-28068. [PMID: 19632986 DOI: 10.1074/jbc.m109.034231] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Ca(2+)-binding protein calmodulin (CaM) has been shown to bind directly to cytoplasmic domains of some G protein-coupled receptors, including the dopamine D(2) receptor. CaM binds to the N-terminal portion of the long third intracellular loop of the D(2) receptor, within an Arg-rich epitope that is also involved in the binding to G(i/o) proteins and to the adenosine A(2A) receptor, with the formation of A(2A)-D(2) receptor heteromers. In the present work, by using proteomics and bioluminescence resonance energy transfer (BRET) techniques, we provide evidence for the binding of CaM to the A(2A) receptor. By using BRET and sequential resonance energy transfer techniques, evidence was obtained for CaM-A(2A)-D(2) receptor oligomerization. BRET competition experiments indicated that, in the A(2A)-D(2) receptor heteromer, CaM binds preferentially to a proximal C terminus epitope of the A(2A) receptor. Furthermore, Ca(2+) was found to induce conformational changes in the CaM-A(2A)-D(2) receptor oligomer and to selectively modulate A(2A) and D(2) receptor-mediated MAPK signaling in the A(2A)-D(2) receptor heteromer. These results may have implications for basal ganglia disorders, since A(2A)-D(2) receptor heteromers are being considered as a target for anti-parkinsonian agents.
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Affiliation(s)
- Gemma Navarro
- Institut d'Investigacions Biomèdiques August Pi i Sunyer, Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas, and Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Marisol S Aymerich
- Centro de Investigación Médica Aplicada Neurociencias (CIMA), Universidad de Navarra, Avda. Pio XII 55, 31008 Pamplona, Spain
| | - Daniel Marcellino
- Department of Neuroscience, Karolinska Institute, 17177 Stockholm, Sweden
| | - Antoni Cortés
- Institut d'Investigacions Biomèdiques August Pi i Sunyer, Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas, and Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Vicent Casadó
- Institut d'Investigacions Biomèdiques August Pi i Sunyer, Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas, and Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Josefa Mallol
- Institut d'Investigacions Biomèdiques August Pi i Sunyer, Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas, and Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Enric I Canela
- Institut d'Investigacions Biomèdiques August Pi i Sunyer, Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas, and Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Luigi Agnati
- Department of Neuroscience, Karolinska Institute, 17177 Stockholm, Sweden
| | - Amina S Woods
- National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, Maryland 21224
| | - Kjell Fuxe
- Department of Neuroscience, Karolinska Institute, 17177 Stockholm, Sweden
| | - Carmen Lluís
- Institut d'Investigacions Biomèdiques August Pi i Sunyer, Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas, and Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Jose Luis Lanciego
- Centro de Investigación Médica Aplicada Neurociencias (CIMA), Universidad de Navarra, Avda. Pio XII 55, 31008 Pamplona, Spain
| | - Sergi Ferré
- National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, Maryland 21224
| | - Rafael Franco
- Institut d'Investigacions Biomèdiques August Pi i Sunyer, Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas, and Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain; Centro de Investigación Médica Aplicada Neurociencias (CIMA), Universidad de Navarra, Avda. Pio XII 55, 31008 Pamplona, Spain.
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20
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Gurevich VV, Gurevich EV. How and why do GPCRs dimerize? Trends Pharmacol Sci 2008; 29:234-40. [PMID: 18384890 DOI: 10.1016/j.tips.2008.02.004] [Citation(s) in RCA: 152] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2007] [Revised: 02/26/2008] [Accepted: 02/27/2008] [Indexed: 12/27/2022]
Abstract
Dimerization is fairly common in the G-protein-coupled receptor (GPCR) superfamily. First attempts to rationalize this phenomenon gave rise to an idea that two receptors in a dimer could be necessary to bind a single molecule of G protein or arrestin. Although GPCRs, G proteins and arrestins were crystallized only in their inactive conformations (in which they do not interact), the structures appeared temptingly compatible with this beautiful model. However, it did not survive the rigors of experimental testing: several recent studies unambiguously demonstrated that one receptor molecule is sufficient to activate a G protein and bind arrestin. Thus, to figure out the biological role of receptor self-association we must focus on other functions of GPCRs at different stages of their functional cycle.
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Affiliation(s)
- Vsevolod V Gurevich
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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21
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Gurevich VV, Gurevich EV. GPCR monomers and oligomers: it takes all kinds. Trends Neurosci 2008; 31:74-81. [PMID: 18199492 DOI: 10.1016/j.tins.2007.11.007] [Citation(s) in RCA: 160] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2007] [Revised: 11/20/2007] [Accepted: 11/21/2007] [Indexed: 02/01/2023]
Abstract
Accumulating evidence of G-protein-coupled receptor (GPCR) oligomerization on the one hand and perfect functionality of monomeric receptors on the other creates an impression of controversy. However, the GPCR superfamily is extremely diverse, both structurally and functionally. The life cycle of each receptor includes many stages: synthesis, quality control in the endoplasmic reticulum, maturation in the Golgi, delivery to the plasma membrane (where it can be in the inactive or active state, in complex with cognate G protein, G-protein-coupled receptor kinase or arrestin), endocytosis and subsequent sorting in endosomes. Different GPCR subtypes, and even the same receptor at different stages of its life cycle, most likely exist in different oligomerization states, from monomers to dimers and possibly higher-order oligomers.
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Affiliation(s)
- Vsevolod V Gurevich
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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22
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Bush CF, Jones SV, Lyle AN, Minneman KP, Ressler KJ, Hall RA. Specificity of Olfactory Receptor Interactions with Other G Protein-coupled Receptors. J Biol Chem 2007; 282:19042-51. [PMID: 17472961 DOI: 10.1074/jbc.m610781200] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Studies on olfactory receptor (OR) pharmacology have been hindered by the poor plasma membrane localization of most ORs in heterologous cells. We previously reported that association with the beta(2)-adrenergic receptor (beta(2)-AR) facilitates functional expression of the OR M71 at the plasma membrane of HEK-293 cells. In the present study, we examined the specificity of M71 interactions with other G protein-coupled receptors (GPCRs). M71 was co-expressed in HEK-293 cells with 42 distinct GPCRs, and the vast majority of these receptors had no significant effect on M71 surface expression. However, co-expression with three subtypes of purinergic receptor (P2Y(1)R, P2Y(2)R, and A(2A)R) resulted in markedly enhanced plasma membrane localization of M71. Agonist stimulation of M71 co-expressed with P2Y(1)R and P2Y(2)R activated the mitogen-activated protein kinase pathway via coupling of M71 to Galpha(o). We also examined the ability of beta(2)-AR, P2Y(1)R, P2Y(2)R, and A(2A)Rto interact with and regulate ORs beyond M71. We found that co-expression of beta(2)-AR or the purinergic receptors enhanced the surface expression for an M71 subfamily member but not for several other ORs from different subfamilies. In addition, through chimeric receptor studies, we determined that the second transmembrane domain of beta(2)-AR is necessary for beta(2)-AR facilitation of M71 plasma membrane localization. These studies shed light on the specificity of OR interactions with other GPCRs and the mechanisms governing olfactory receptor trafficking.
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MESH Headings
- Acetophenones/pharmacology
- Animals
- Cell Line
- Cell Membrane/metabolism
- Humans
- Kidney/cytology
- Lac Operon
- MAP Kinase Signaling System/physiology
- Mice
- Mice, Transgenic
- Olfactory Receptor Neurons/physiology
- Photosensitizing Agents/pharmacology
- Protein Structure, Tertiary
- Rats
- Receptors, Adrenergic, alpha-2/genetics
- Receptors, Adrenergic, alpha-2/metabolism
- Receptors, Adrenergic, beta-2/chemistry
- Receptors, Adrenergic, beta-2/genetics
- Receptors, Adrenergic, beta-2/metabolism
- Receptors, G-Protein-Coupled/metabolism
- Receptors, Odorant/agonists
- Receptors, Odorant/genetics
- Receptors, Odorant/metabolism
- Receptors, Purinergic P2/genetics
- Receptors, Purinergic P2/metabolism
- Receptors, Purinergic P2Y1
- Receptors, Purinergic P2Y2
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Affiliation(s)
- Cristina F Bush
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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23
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Salim S, Standifer KM, Eikenburg DC. Extracellular signal-regulated kinase 1/2-mediated transcriptional regulation of G-protein-coupled receptor kinase 3 expression in neuronal cells. J Pharmacol Exp Ther 2007; 321:51-9. [PMID: 17255468 DOI: 10.1124/jpet.106.116921] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Relatively small changes in G-protein-coupled receptor kinase (GRK) 3 expression (approximately 2-fold) profoundly affect alpha2-adrenergic receptor (AR) function and preferentially regulate neuronal alpha2A- and alpha2B-AR signaling. In the present study, we provide evidence that epinephrine (EPI)-induced up-regulation of GRK3 protein expression in two neuronal cell lines, BE(2)-C cells (endogenously express alpha2A- and beta2AR) and BN17 cells [endogenously express alpha2B (NG108) and transfected to express beta2-AR] is due in part to increased GRK3 gene expression. In both cell lines, the increase in GRK3 transcription occurred via an extracellular signal-regulated kinase (ERK) 1/2-dependent mechanism because the increase in GRK3 mRNA is eliminated in the presence of the mitogen-activated protein kinase/ERK kinase 1/2 inhibitor, U0126 [1,4-diamino-2,3-dicyano-1,4-bis (2-amino phenylthiobutadiene)]. EPI-induced GRK3 mRNA up-regulation also is prevented in the presence of propranolol or phentolamine. Moreover, GRK3 mRNA did not increase in response to EPI treatment in NG108 cells (endogenously express alpha2B-AR with no beta2-AR). Both these results suggest that simultaneous activation of alpha2- and beta2-AR by EPI is required for the ERK1/2-dependent increase in GRK3 mRNA. The EPI-induced increase in GRK3 mRNA was unaffected in the presence of the protein kinase C inhibitor, chelerythrine chloride. Finally, EPI treatment resulted in increased nuclear translocation and accumulation of the transcription factors, Sp-1 and Ap-2, in BE(2)-C cells. Taken together, our results demonstrate the involvement of the ERK1/2 pathway in selective up-regulation of GRK3 mRNA expression, possibly via activation of Sp-1 and Ap-2 transcription factors in neuronal cells.
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Affiliation(s)
- Samina Salim
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, TX 77204-5037, USA
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24
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Wang Q, Limbird LE. Regulation of alpha2AR trafficking and signaling by interacting proteins. Biochem Pharmacol 2006; 73:1135-45. [PMID: 17229402 PMCID: PMC1885238 DOI: 10.1016/j.bcp.2006.12.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2006] [Revised: 12/11/2006] [Accepted: 12/20/2006] [Indexed: 01/23/2023]
Abstract
The continuing discovery of new G protein-coupled receptor (GPCR) interacting proteins and clarification of the functional consequences of these interactions has revealed multiple roles for these events. Some of these interactions serve to scaffold GPCRs to particular cellular micro-compartments or to tether them to defined signaling molecules, while other GPCR-protein interactions control GPCR trafficking and the kinetics of GPCR-mediated signaling transduction. This review provides a general overview of the variety of GPCR-protein interactions reported to date, and then focuses on one prototypical GPCR, the alpha(2)AR, and the in vitro and in vivo significance of its reciprocal interactions with arrestin and spinophilin. It seems appropriate to recognize the life and career of Arthur Hancock with a summary of studies that both affirm and surprise our preconceived notions of how nature is designed, as his career-long efforts similarly affirmed the complexity of human biology and attempted to surprise pathological changes in that biology with novel, discovery-based therapeutic interventions. Dr. Hancock's love of life, of family, and of commitment to making the world a better place are a model of the life well lived, and truly missed by those who were privileged to know, and thus love, him.
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Affiliation(s)
- Qin Wang
- Department of Physiology and Biophysics, University of Alabama at Birmingham, Birmingham, AL35294
| | - Lee E. Limbird
- Department of Biomedical Sciences, Meharry Medical College, Nashville, TN 37208
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