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Bonanno SL, Sanfilippo P, Eamani A, Sampson MM, Binu K, Li K, Burns GD, Makar ME, Zipursky SL, Krantz DE. Constitutive and conditional epitope-tagging of endogenous G protein coupled receptors in Drosophila. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.27.573472. [PMID: 38234787 PMCID: PMC10793450 DOI: 10.1101/2023.12.27.573472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
To visualize the cellular and subcellular localization of neuromodulatory G-protein coupled receptors (GPCRs) in Drosophila , we implement a molecular strategy recently used to add epitope tags to ionotropic receptors at their endogenous loci. Leveraging evolutionary conservation to identify sites more likely to permit insertion of a tag, we generated constitutive and conditional tagged alleles for Drosophila 5-HT1A, 5-HT2A, 5-HT2B, Octβ1R, Octβ2R, two isoforms of OAMB, and mGluR. The conditional alleles allow for the restricted expression of tagged receptor in specific cell types, an option not available for any previous reagents to label these proteins. We show that 5-HT1A and 5-HT2B localize to the mushroom bodies and central complex respectively, as predicted by their roles in sleep. By contrast, the unexpected enrichment of Octβ1R in the central complex and of 5-HT1A and 5-HT2A to nerve terminals in lobular columnar cells in the visual system suggest new hypotheses about their function at these sites. Using an additional tagged allele of the serotonin transporter, a marker of serotonergic tracts, we demonstrate diverse spatial relationships between postsynaptic 5-HT receptors and presynaptic 5-HT neurons, consistent with the importance of both synaptic and volume transmission. Finally, we use the conditional allele of 5-HT1A to show that it localizes to distinct sites within the mushroom bodies as both a postsynaptic receptor in Kenyon cells and a presynaptic autoreceptor. Significance Statement In Drosophila , despite remarkable advances in both connectomic and genomic studies, antibodies to many aminergic GPCRs are not available. We have overcome this obstacle using evolutionary conservation to identify loci in GPCRs amenable to epitope-tagging, and CRISPR/Cas9 genome editing to generated eight novel lines. This method also may be applied to other GPCRs and allows cell-specific expression of the tagged locus. We have used the tagged alleles we generated to address several questions that remain poorly understood. These include the relationship between pre- and post-synaptic sites that express the same receptor, and the use of relatively distant targets by pre-synaptic release sites that may employ volume transmission as well as standard synaptic signaling.
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Kawahata I, Fukunaga K. Pathogenic Impact of Fatty Acid-Binding Proteins in Parkinson's Disease-Potential Biomarkers and Therapeutic Targets. Int J Mol Sci 2023; 24:17037. [PMID: 38069360 PMCID: PMC10707307 DOI: 10.3390/ijms242317037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 11/26/2023] [Accepted: 11/30/2023] [Indexed: 12/18/2023] Open
Abstract
Parkinson's disease is a neurodegenerative condition characterized by motor dysfunction resulting from the degeneration of dopamine-producing neurons in the midbrain. This dopamine deficiency gives rise to a spectrum of movement-related symptoms, including tremors, rigidity, and bradykinesia. While the precise etiology of Parkinson's disease remains elusive, genetic mutations, protein aggregation, inflammatory processes, and oxidative stress are believed to contribute to its development. In this context, fatty acid-binding proteins (FABPs) in the central nervous system, FABP3, FABP5, and FABP7, impact α-synuclein aggregation, neurotoxicity, and neuroinflammation. These FABPs accumulate in mitochondria during neurodegeneration, disrupting their membrane potential and homeostasis. In particular, FABP3, abundant in nigrostriatal dopaminergic neurons, is responsible for α-synuclein propagation into neurons and intracellular accumulation, affecting the loss of mesencephalic tyrosine hydroxylase protein, a rate-limiting enzyme of dopamine biosynthesis. This review summarizes the characteristics of FABP family proteins and delves into the pathogenic significance of FABPs in the pathogenesis of Parkinson's disease. Furthermore, it examines potential novel therapeutic targets and early diagnostic biomarkers for Parkinson's disease and related neurodegenerative disorders.
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Affiliation(s)
- Ichiro Kawahata
- Department of CNS Drug Innovation, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan;
| | - Kohji Fukunaga
- Department of CNS Drug Innovation, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan;
- BRI Pharma Inc., Sendai 982-0804, Japan
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Kim KM. Unveiling the Differences in Signaling and Regulatory Mechanisms between Dopamine D2 and D3 Receptors and Their Impact on Behavioral Sensitization. Int J Mol Sci 2023; 24:ijms24076742. [PMID: 37047716 PMCID: PMC10095578 DOI: 10.3390/ijms24076742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 03/25/2023] [Accepted: 03/28/2023] [Indexed: 04/09/2023] Open
Abstract
Dopamine receptors are classified into five subtypes, with D2R and D3R playing a crucial role in regulating mood, motivation, reward, and movement. Whereas D2R are distributed widely across the brain, including regions responsible for motor functions, D3R are primarily found in specific areas related to cognitive and emotional functions, such as the nucleus accumbens, limbic system, and prefrontal cortex. Despite their high sequence homology and similar signaling pathways, D2R and D3R have distinct regulatory properties involving desensitization, endocytosis, posttranslational modification, and interactions with other cellular components. In vivo, D3R is closely associated with behavioral sensitization, which leads to increased dopaminergic responses. Behavioral sensitization is believed to result from D3R desensitization, which removes the inhibitory effect of D3R on related behaviors. Whereas D2R maintains continuous signal transduction through agonist-induced receptor phosphorylation, arrestin recruitment, and endocytosis, which recycle and resensitize desensitized receptors, D3R rarely undergoes agonist-induced endocytosis and instead is desensitized after repeated agonist exposure. In addition, D3R undergoes more extensive posttranslational modifications, such as glycosylation and palmitoylation, which are needed for its desensitization. Overall, a series of biochemical settings more closely related to D3R could be linked to D3R-mediated behavioral sensitization.
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Affiliation(s)
- Kyeong-Man Kim
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju 61186, Republic of Korea
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4
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Jia W, Kawahata I, Cheng A, Sasaki T, Sasaoka T, Fukunaga K. Amelioration of Nicotine-Induced Conditioned Place Preference Behaviors in Mice by an FABP3 Inhibitor. Int J Mol Sci 2023; 24:ijms24076644. [PMID: 37047614 PMCID: PMC10095245 DOI: 10.3390/ijms24076644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 03/30/2023] [Accepted: 03/31/2023] [Indexed: 04/05/2023] Open
Abstract
We previously demonstrated that fatty acid-binding protein 3 null (FABP3−/−) mice exhibit resistance to nicotine-induced conditioned place preference (CPP). Here, we confirm that the FABP3 inhibitor, MF1 ((4-(2-(1-(2-chlorophenyl)-5-phenyl-1H-pyrazol-3-yl)phenoxy) butanoic acid), successfully reduces nicotine-induced CPP scores in mice. MF1 (0.3 or 1.0 mg/kg) was orally administered 30 min before nicotine, and CPP scores were assessed in the conditioning, withdrawal, and relapse phases. MF1 treatment decreased CPP scores in a dose-dependent manner. Failure of CPP induction by MF1 (1.0 mg/kg, p.o.) was associated with the inhibition of both CaMKII and ERK activation in the nucleus accumbens (NAc) and hippocampal CA1 regions. MF1 treatment reduced nicotine-induced increases in phosphorylated CaMKII and cAMP-response element-binding protein (CREB)-positive cells. Importantly, the increase in dopamine D2 receptor (D2R) levels following chronic nicotine exposure was inhibited by MF1 treatment. Moreover, the quinpirole (QNP)-induced increase in the level of CaMKII and ERK phosphorylation was significantly inhibited by MF1 treatment of cultured NAc slices from wild type (WT) mice; however, QNP treatment had no effect on CaMKII and ERK phosphorylation levels in the NAc of D2R null mice. Taken together, these results show that MF1 treatment suppressed D2R/FABP3 signaling, thereby preventing nicotine-induced CPP induction. Hence, MF1 can be used as a novel drug to block addiction to nicotine and other drugs by inhibiting the dopaminergic system.
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Affiliation(s)
- Wenbin Jia
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
- Department of CNS Drug Innovation, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Ichiro Kawahata
- Department of CNS Drug Innovation, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - An Cheng
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
- Department of CNS Drug Innovation, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Takuya Sasaki
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Toshikuni Sasaoka
- Department of Comparative and Experimental Medicine, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Kohji Fukunaga
- Department of CNS Drug Innovation, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
- BRI Pharma Inc., Sendai 982-0804, Japan
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5
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Kawahata I, Fukunaga K. Endocytosis of dopamine receptor: Signaling in brain. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2023; 196:99-111. [PMID: 36813367 DOI: 10.1016/bs.pmbts.2022.09.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
This chapter describes the physiological significance of dopamine receptor endocytosis and the consequence of the receptor signaling. Endocytosis of dopamine receptors is regulated by many components such as clathrin, β-arrestin, caveolin, and Rab family proteins. The dopamine receptors escape from lysosomal digestion, and their recycling occurs rapidly, reinforcing the dopaminergic signal transduction. In addition, the pathological impact of the receptors interacting with specific proteins has been the focus of much attention. Based on this background, this chapter provides an in-depth understanding of the mechanisms of molecules interacting with dopamine receptors and discusses the potential pharmacotherapeutic targets for α-synucleinopathies and neuropsychiatric disorders.
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Affiliation(s)
- Ichiro Kawahata
- Department of CNS drug innovation, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan.
| | - Kohji Fukunaga
- Department of CNS drug innovation, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan.
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Pivonello R, Pivonello C, Simeoli C, De Martino MC, Colao A. The dopaminergic control of Cushing's syndrome. J Endocrinol Invest 2022; 45:1297-1315. [PMID: 35460460 PMCID: PMC9184412 DOI: 10.1007/s40618-021-01661-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Accepted: 08/06/2021] [Indexed: 12/14/2022]
Abstract
Cushing's Syndrome (CS), or chronic endogenous hypercortisolism, is a rare and serious disease due to corticotroph pituitary (Cushing's disease, CD) and extra-pituitary (ectopic CS) tumours overproducing ACTH, or cortisol-secreting adrenal tumours or lesions (adrenal CS). The first-line treatment for CS is represented by the surgical removal of the responsible tumour, but surgery might be unfeasible or ineffective and medical treatment can be required in a relevant percentage of patients with CS, especially CD and ectopic CS. Corticotroph pituitary and extra-pituitary tumours, as well as adrenal tumours and lesions responsible for CS express dopamine receptors (DRs), which have been found to mediate inhibition of hormone secretion and/or cell proliferation in experimental setting, suggesting that dopaminergic system, particularly DRs, might represent a target for the treatment of CS. Dopamine agonists (DAs), particularly cabergoline (CAB), are currently used as off-label treatment for CD, the most common form of CS, demonstrating efficacy in controlling hormone secretion and tumour growth in a relevant number of cases, with the improvement of clinical picture, and displaying good safety profile. Therefore, CAB may be considered a reasonable alternative treatment for persistent or recurrent CD after pituitary surgery failure, but occasionally also before pituitary surgery, as adjuvant treatment, or even instead of pituitary surgery as first-line treatment in case of surgery contraindications or refusal. A certain beneficial effect of CAB has been also reported in ectopic CS. However, the role of DAs in the clinical management of the different types of CS requires further evaluations.
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Affiliation(s)
- R Pivonello
- Dipartimento Di Medicina Clinica E Chirurgia, Sezione Di Endocrinologia, Università Federico II Di Napoli, Naples, Italy.
- UNESCO Chair for Health Education and Sustainable Development, Federico II University, Naples, Italy.
| | - C Pivonello
- Dipartimento Di Medicina Clinica E Chirurgia, Sezione Di Endocrinologia, Università Federico II Di Napoli, Naples, Italy
| | - C Simeoli
- Dipartimento Di Medicina Clinica E Chirurgia, Sezione Di Endocrinologia, Università Federico II Di Napoli, Naples, Italy
| | - M C De Martino
- Dipartimento Di Medicina Clinica E Chirurgia, Sezione Di Endocrinologia, Università Federico II Di Napoli, Naples, Italy
| | - A Colao
- Dipartimento Di Medicina Clinica E Chirurgia, Sezione Di Endocrinologia, Università Federico II Di Napoli, Naples, Italy
- UNESCO Chair for Health Education and Sustainable Development, Federico II University, Naples, Italy
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Kawahata I, Fukunaga K. Impact of fatty acid-binding proteins and dopamine receptors on α-synucleinopathy. J Pharmacol Sci 2022; 148:248-254. [DOI: 10.1016/j.jphs.2021.12.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 11/29/2021] [Accepted: 12/07/2021] [Indexed: 12/27/2022] Open
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Kawahata I, Fukunaga K. [Development of therapeutic peptides for Lewy body diseases preventing α-synuclein propagation]. Nihon Yakurigaku Zasshi 2022; 157:401-404. [PMID: 36328546 DOI: 10.1254/fpj.22055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
With the advent of a super-aging society, overcoming age-related neurological diseases and developing fundamental therapeutic agents are urgent issues. In Lewy body diseases such as Parkinson's disease and dementia with Lewy bodies, the accumulation and aggregation of α-synuclein in the neuronal cells, called Lewy bodies, are known as pathological features. Intracellular accumulation of the causative protein α-synuclein in the central nervous system requires an uptake process into neurons. Type 3 fatty acid-binding protein (FABP3) is highly expressed in dopaminergic neurons and has the ability to bind dopamine receptors, particularly dopamine D2 long type (D2L) receptors, which are abundantly localized on caveolae structures in the plasma membrane. We found that dopaminergic neurons do not take up α-synuclein in FABP3 knockout or D2L receptor-selective knockout mice. Next, we found that the C-terminal deletion of α-synuclein reduces the uptake ability. α-Synuclein has a FABP3 binding site in its C-terminal region. On this point, exposure to the C-terminal peptide reduced α-synuclein uptake into dopaminergic neurons. Based on these findings, this article describes the unique mechanism of the propagation and uptake process of α-synuclein, focusing on the physiological significance of FABP3 and dopamine D2 receptors. Additionally, we will review the development status of therapeutic peptide candidates for Lewy body diseases, and then discuss the novel pathogenic mechanism of Lewy body disease as well as the potential of fundamental therapeutics targeting the uptake process of α-synuclein.
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Affiliation(s)
- Ichiro Kawahata
- Department of CNS Drug Innovation, Graduate School of Pharmaceutical Sciences, Tohoku University
| | - Kohji Fukunaga
- Department of CNS Drug Innovation, Graduate School of Pharmaceutical Sciences, Tohoku University
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Cholesterol-dependent endocytosis of GPCRs: implications in pathophysiology and therapeutics. Biophys Rev 2021; 13:1007-1017. [DOI: 10.1007/s12551-021-00878-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 10/26/2021] [Indexed: 10/19/2022] Open
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Cheng A, Jia W, Kawahata I, Fukunaga K. Impact of Fatty Acid-Binding Proteins in α-Synuclein-Induced Mitochondrial Injury in Synucleinopathy. Biomedicines 2021; 9:biomedicines9050560. [PMID: 34067791 PMCID: PMC8156290 DOI: 10.3390/biomedicines9050560] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Revised: 05/13/2021] [Accepted: 05/14/2021] [Indexed: 02/07/2023] Open
Abstract
Synucleinopathies are diverse diseases with motor and cognitive dysfunction due to progressive neuronal loss or demyelination, due to oligodendrocyte loss in the brain. While the etiology of neurodegenerative disorders (NDDs) is likely multifactorial, mitochondrial injury is one of the most vital factors in neuronal loss and oligodendrocyte dysfunction, especially in Parkinson’s disease, dementia with Lewy body, multiple system atrophy, and Krabbe disease. In recent years, the abnormal accumulation of highly neurotoxic α-synuclein in the mitochondrial membrane, which leads to mitochondrial dysfunction, was well studied. Furthermore, fatty acid-binding proteins (FABPs), which are members of a superfamily and are essential in fatty acid trafficking, were reported to trigger α-synuclein oligomerization in neurons and glial cells and to target the mitochondrial outer membrane, thereby causing mitochondrial loss. Here, we provide an updated overview of recent findings on FABP and α-synuclein interactions and mitochondrial injury in NDDs.
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Affiliation(s)
- An Cheng
- Departments of Pharmacology, Graduate School of Pharmaceutical Science, Tohoku University, Sendai 980-8578, Japan; (A.C.); (W.J.); (I.K.)
| | - Wenbin Jia
- Departments of Pharmacology, Graduate School of Pharmaceutical Science, Tohoku University, Sendai 980-8578, Japan; (A.C.); (W.J.); (I.K.)
| | - Ichiro Kawahata
- Departments of Pharmacology, Graduate School of Pharmaceutical Science, Tohoku University, Sendai 980-8578, Japan; (A.C.); (W.J.); (I.K.)
- Department of CNS Drug Innovation, Graduate School of Pharmaceutical Science, Tohoku University, Sendai 980-8578, Japan
| | - Kohji Fukunaga
- Departments of Pharmacology, Graduate School of Pharmaceutical Science, Tohoku University, Sendai 980-8578, Japan; (A.C.); (W.J.); (I.K.)
- Department of CNS Drug Innovation, Graduate School of Pharmaceutical Science, Tohoku University, Sendai 980-8578, Japan
- Correspondence: ; Tel.: +81-(22)-795-6837
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Abstract
Changes in glycosylation on proteins or lipids are one of the hallmarks of tumorigenesis. In many cases, it is still not understood how glycan information is translated into biological function. In this review, we discuss at the example of specific cancer-related glycoproteins how their endocytic uptake into eukaryotic cells is tuned by carbohydrate modifications. For this, we not only focus on overall uptake rates, but also illustrate how different uptake processes-dependent or not on the conventional clathrin machinery-are used under given glycosylation conditions. Furthermore, we discuss the role of certain sugar-binding proteins, termed galectins, to tune glycoprotein uptake by inducing their crosslinking into lattices, or by co-clustering them with glycolipids into raft-type membrane nanodomains from which the so-called clathrin-independent carriers (CLICs) are formed for glycoprotein internalization into cells. The latter process has been termed glycolipid-lectin (GL-Lect) hypothesis, which operates in a complementary manner to the clathrin pathway and galectin lattices.
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Affiliation(s)
- Ludger Johannes
- Cellular and Chemical Biology Unit, INSERM U1143, CNRS UMR3666, Institut Curie, PSL Research University, 26 rue d'Ulm, 75248, Paris Cedex 05, France.
| | - Anne Billet
- Cellular and Chemical Biology Unit, INSERM U1143, CNRS UMR3666, Institut Curie, PSL Research University, 26 rue d'Ulm, 75248, Paris Cedex 05, France.,Université de Paris, F-75005, Paris, France
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Dopamine D2 Long Receptors Are Critical for Caveolae-Mediated α-Synuclein Uptake in Cultured Dopaminergic Neurons. Biomedicines 2021; 9:biomedicines9010049. [PMID: 33429895 PMCID: PMC7826971 DOI: 10.3390/biomedicines9010049] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/03/2021] [Accepted: 01/05/2021] [Indexed: 12/14/2022] Open
Abstract
α-synuclein accumulation into dopaminergic neurons is a pathological hallmark of Parkinson's disease. We previously demonstrated that fatty acid-binding protein 3 (FABP3) is critical for α-synuclein uptake and propagation to accumulate in dopaminergic neurons. FABP3 is abundant in dopaminergic neurons and interacts with dopamine D2 receptors, specifically the long type (D2L). Here, we investigated the importance of dopamine D2L receptors in the uptake of α-synuclein monomers and their fibrils. We employed mesencephalic neurons derived from dopamine D2L
-/-, dopamine D2 receptor null (D2 null), FABP3-/-, and wild type C57BL6 mice, and analyzed the uptake ability of fluorescence-conjugated α-synuclein monomers and fibrils. We found that D2L receptors are co-localized with FABP3. Immunocytochemistry revealed that TH+ D2L-/- or D2 null neurons do not take up α-synuclein monomers. The deletion of α-synuclein C-terminus completely abolished the uptake to dopamine neurons. Likewise, dynasore, a dynamin inhibitor, and caveolin-1 knockdown also abolished the uptake. D2L and FABP3 were also critical for α-synuclein fibrils uptake. D2L and accumulated α-synuclein fibrils were well co-localized. These data indicate that dopamine D2L with a caveola structure coupled with FABP3 is critical for α-synuclein uptake by dopaminergic neurons, suggesting a novel pathogenic mechanism of synucleinopathies, including Parkinson's disease.
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Addabbo F, Baglioni V, Schrag A, Schwarz MJ, Dietrich A, Hoekstra PJ, Martino D, Buttiglione M. Anti-dopamine D2 receptor antibodies in chronic tic disorders. Dev Med Child Neurol 2020; 62:1205-1212. [PMID: 32644201 DOI: 10.1111/dmcn.14613] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/18/2020] [Indexed: 12/11/2022]
Abstract
AIM To investigate the association between circulating anti-dopamine D2 receptor (D2R) autoantibodies and the exacerbation of tics in children with chronic tic disorders (CTDs). METHOD One hundred and thirty-seven children with CTDs (108 males, 29 females; mean age [SD] 10y 0mo [2y 7mo], range 4-16y) were recruited over 18 months. Patients were assessed at baseline, at tic exacerbation, and at 2 months after exacerbation. Serum anti-D2R antibodies were evaluated using a cell-based assay and blinded immunofluorescence microscopy scoring was performed by two raters. The association between visit type and presence of anti-D2R antibodies was measured with McNemar's test and repeated-measure logistic regression models, adjusting for potential demographic and clinical confounders. RESULTS At exacerbation, 11 (8%) participants became anti-D2R-positive ('early peri-exacerbation seroconverters'), and nine (6.6%) became anti-D2R-positive at post-exacerbation ('late peri-exacerbation seroconverters'). The anti-D2R antibodies were significantly associated with exacerbations when compared to baseline (McNemar's odds ratio=11, p=0.003) and conditional logistic regression confirmed this association (Z=3.49, p<0.001) after adjustment for demographic and clinical data and use of psychotropic drugs. INTERPRETATION There is a potential association between immune mechanisms and the severity course of tics in adolescents with CTDs.
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Affiliation(s)
- Francesco Addabbo
- Department of Biomedical Sciences and Human Oncology, University of Bari "Aldo Moro", Bari, Italy
| | - Valentina Baglioni
- Department of Human Neurosciences, Sapienza University of Rome, Institute of Child and Adolescent Neurology and Psychiatry, Rome, Italy
| | - Anette Schrag
- Department of Clinical Neurosciences, UCL Institute of Neurology, Royal Free Campus, London, UK
| | - Markus J Schwarz
- Institute of Laboratory Medicine, University Hospital, LMU Munich, Munich, Germany
| | - Andrea Dietrich
- Department of Child and Adolescent Psychiatry, University Medical Center Groningen, Groningen, the Netherlands
| | - Pieter J Hoekstra
- Department of Child and Adolescent Psychiatry, University Medical Center Groningen, Groningen, the Netherlands
| | - Davide Martino
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Health Sciences Centre, Calgary, AB, Canada
| | - Maura Buttiglione
- Department of Biomedical Sciences and Human Oncology, University of Bari "Aldo Moro", Bari, Italy
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Blagotinšek Cokan K, Mavri M, Rutland CS, Glišić S, Senćanski M, Vrecl M, Kubale V. Critical Impact of Different Conserved Endoplasmic Retention Motifs and Dopamine Receptor Interacting Proteins (DRIPs) on Intracellular Localization and Trafficking of the D 2 Dopamine Receptor (D 2-R) Isoforms. Biomolecules 2020; 10:biom10101355. [PMID: 32977535 PMCID: PMC7598153 DOI: 10.3390/biom10101355] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 09/09/2020] [Accepted: 09/18/2020] [Indexed: 01/13/2023] Open
Abstract
The type 2 dopamine receptor D2 (D2-R), member of the G protein-coupled receptor (GPCR) superfamily, exists in two isoforms, short (D2S-R) and long (D2L-R). They differ by an additional 29 amino acids (AA) in the third cytoplasmic loop (ICL3) of the D2L-R. These isoforms differ in their intracellular localization and trafficking functionality, as D2L-R possesses a larger intracellular pool, mostly in the endoplasmic reticulum (ER). This review focuses on the evolutionarily conserved motifs in the ICL3 of the D2-R and proteins interacting with the ICL3 of both isoforms, specifically with the 29 AA insert. These motifs might be involved in D2-R exit from the ER and have an impact on cell-surface and intracellular localization and, therefore, also play a role in the function of dopamine receptor signaling, ligand binding and possible homo/heterodimerization. Our recent bioinformatic data on potential new interaction partners for the ICL3 of D2-Rs are also presented. Both are highly relevant, and have clinical impacts on the pathophysiology of several diseases such as Parkinson’s disease, schizophrenia, Tourette’s syndrome, Huntington’s disease, manic depression, and others, as they are connected to a variety of essential motifs and differences in communication with interaction partners.
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Affiliation(s)
- Kaja Blagotinšek Cokan
- Department of Anatomy, Histology with Embryology and Cytology, Institute of Preclinical Sciences, Veterinary Faculty, University of Ljubljana, Gerbičeva 60, 1000 Ljubljana, Slovenia; (K.B.C.); (M.M.); (M.V.)
| | - Maša Mavri
- Department of Anatomy, Histology with Embryology and Cytology, Institute of Preclinical Sciences, Veterinary Faculty, University of Ljubljana, Gerbičeva 60, 1000 Ljubljana, Slovenia; (K.B.C.); (M.M.); (M.V.)
| | - Catrin Sian Rutland
- School of Veterinary Medicine and Science, Medical Faculty, University of Nottingham, Sutton, Bonington Campus, Loughborough LE12 5RD, UK;
| | - Sanja Glišić
- Center for Multidisciplinary Research, Institute of Nuclear Sciences VINCA, University of Belgrade, Mike Petrovića Alasa 12-14, 11351 Vinča, Belgrade, Serbia; (S.G.); (M.S.)
| | - Milan Senćanski
- Center for Multidisciplinary Research, Institute of Nuclear Sciences VINCA, University of Belgrade, Mike Petrovića Alasa 12-14, 11351 Vinča, Belgrade, Serbia; (S.G.); (M.S.)
| | - Milka Vrecl
- Department of Anatomy, Histology with Embryology and Cytology, Institute of Preclinical Sciences, Veterinary Faculty, University of Ljubljana, Gerbičeva 60, 1000 Ljubljana, Slovenia; (K.B.C.); (M.M.); (M.V.)
| | - Valentina Kubale
- Department of Anatomy, Histology with Embryology and Cytology, Institute of Preclinical Sciences, Veterinary Faculty, University of Ljubljana, Gerbičeva 60, 1000 Ljubljana, Slovenia; (K.B.C.); (M.M.); (M.V.)
- Correspondence:
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15
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Janezic EM, Lauer SML, Williams RG, Chungyoun M, Lee KS, Navaluna E, Lau HT, Ong SE, Hague C. N-glycosylation of α 1D-adrenergic receptor N-terminal domain is required for correct trafficking, function, and biogenesis. Sci Rep 2020; 10:7209. [PMID: 32350295 PMCID: PMC7190626 DOI: 10.1038/s41598-020-64102-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 04/09/2020] [Indexed: 01/21/2023] Open
Abstract
G protein-coupled receptor (GPCR) biogenesis, trafficking, and function are regulated by post-translational modifications, including N-glycosylation of asparagine residues. α1D-adrenergic receptors (α1D-ARs) - key regulators of central and autonomic nervous system function - contain two putative N-glycosylation sites within the large N-terminal domain at N65 and N82. However, determining the glycosylation state of this receptor has proven challenging. Towards understanding the role of these putative glycosylation sites, site-directed mutagenesis and lectin affinity purification identified N65 and N82 as bona fide acceptors for N-glycans. Surprisingly, we also report that simultaneously mutating N65 and N82 causes early termination of α1D-AR between transmembrane domain 2 and 3. Label-free dynamic mass redistribution and cell surface trafficking assays revealed that single and double glycosylation deficient mutants display limited function with impaired plasma membrane expression. Confocal microscopy imaging analysis and SNAP-tag sucrose density fractionation assays revealed the dual glycosylation mutant α1D-AR is widely distributed throughout the cytosol and nucleus. Based on these novel findings, we propose α1D-AR transmembrane domain 2 acts as an ER localization signal during active protein biogenesis, and that α1D-AR N-terminal glycosylation is required for complete translation of nascent, functional receptor.
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Affiliation(s)
- Eric M Janezic
- Department of Pharmacology, School of Medicine, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98185, USA
| | - Sophia My-Linh Lauer
- Department of Pharmacology, School of Medicine, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98185, USA
| | - Robert George Williams
- Department of Pharmacology, School of Medicine, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98185, USA
| | - Michael Chungyoun
- Department of Pharmacology, School of Medicine, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98185, USA
| | - Kyung-Soon Lee
- Department of Pharmacology, School of Medicine, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98185, USA
| | - Edelmar Navaluna
- Department of Pharmacology, School of Medicine, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98185, USA
| | - Ho-Tak Lau
- Department of Pharmacology, School of Medicine, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98185, USA
| | - Shao-En Ong
- Department of Pharmacology, School of Medicine, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98185, USA
| | - Chris Hague
- Department of Pharmacology, School of Medicine, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98185, USA.
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16
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Bonsi P, Ponterio G, Vanni V, Tassone A, Sciamanna G, Migliarini S, Martella G, Meringolo M, Dehay B, Doudnikoff E, Zachariou V, Goodchild RE, Mercuri NB, D'Amelio M, Pasqualetti M, Bezard E, Pisani A. RGS9-2 rescues dopamine D2 receptor levels and signaling in DYT1 dystonia mouse models. EMBO Mol Med 2019; 11:emmm.201809283. [PMID: 30552094 PMCID: PMC6328939 DOI: 10.15252/emmm.201809283] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Dopamine D2 receptor signaling is central for striatal function and movement, while abnormal activity is associated with neurological disorders including the severe early-onset DYT1 dystonia. Nevertheless, the mechanisms that regulate D2 receptor signaling in health and disease remain poorly understood. Here, we identify a reduced D2 receptor binding, paralleled by an abrupt reduction in receptor protein level, in the striatum of juvenile Dyt1 mice. This occurs through increased lysosomal degradation, controlled by competition between β-arrestin 2 and D2 receptor binding proteins. Accordingly, we found lower levels of striatal RGS9-2 and spinophilin. Further, we show that genetic depletion of RGS9-2 mimics the D2 receptor loss of DYT1 dystonia striatum, whereas RGS9-2 overexpression rescues both receptor levels and electrophysiological responses in Dyt1 striatal neurons. This work uncovers the molecular mechanism underlying D2 receptor downregulation in Dyt1 mice and in turn explains why dopaminergic drugs lack efficacy in DYT1 patients despite significant evidence for striatal D2 receptor dysfunction. Our data also open up novel avenues for disease-modifying therapeutics to this incurable neurological disorder.
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Affiliation(s)
- Paola Bonsi
- Laboratory of Neurophysiology and Plasticity, IRCCS Fondazione Santa Lucia, Rome, Italy
| | - Giulia Ponterio
- Laboratory of Neurophysiology and Plasticity, IRCCS Fondazione Santa Lucia, Rome, Italy.,Department of Systems Medicine, University Tor Vergata, Rome, Italy
| | - Valentina Vanni
- Laboratory of Neurophysiology and Plasticity, IRCCS Fondazione Santa Lucia, Rome, Italy.,Department of Systems Medicine, University Tor Vergata, Rome, Italy
| | - Annalisa Tassone
- Laboratory of Neurophysiology and Plasticity, IRCCS Fondazione Santa Lucia, Rome, Italy.,Department of Systems Medicine, University Tor Vergata, Rome, Italy
| | - Giuseppe Sciamanna
- Laboratory of Neurophysiology and Plasticity, IRCCS Fondazione Santa Lucia, Rome, Italy.,Department of Systems Medicine, University Tor Vergata, Rome, Italy
| | - Sara Migliarini
- Unit of Cell and Developmental Biology, Department of Biology, University of Pisa, Pisa, Italy
| | - Giuseppina Martella
- Laboratory of Neurophysiology and Plasticity, IRCCS Fondazione Santa Lucia, Rome, Italy.,Department of Systems Medicine, University Tor Vergata, Rome, Italy
| | - Maria Meringolo
- Laboratory of Neurophysiology and Plasticity, IRCCS Fondazione Santa Lucia, Rome, Italy.,Department of Systems Medicine, University Tor Vergata, Rome, Italy
| | - Benjamin Dehay
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France.,CNRS, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France
| | - Evelyne Doudnikoff
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France.,CNRS, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France
| | - Venetia Zachariou
- Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Rose E Goodchild
- Department of Neurosciences, VIB-KU Leuven Center for Brain and Disease Research, KU Leuven, Leuven, Belgium
| | - Nicola B Mercuri
- Laboratory of Neurophysiology and Plasticity, IRCCS Fondazione Santa Lucia, Rome, Italy.,Department of Systems Medicine, University Tor Vergata, Rome, Italy
| | - Marcello D'Amelio
- Laboratory Molecular Neurosciences, IRCCS Fondazione Santa Lucia, Rome, Italy.,Unit of Molecular Neurosciences, Department of Medicine, University Campus-Biomedico, Rome, Italy
| | - Massimo Pasqualetti
- Unit of Cell and Developmental Biology, Department of Biology, University of Pisa, Pisa, Italy.,Center for Neuroscience and Cognitive Systems @UniTn, Istituto Italiano di Tecnologia, Rovereto, Italy
| | - Erwan Bezard
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France.,CNRS, Institut des Maladies Neurodégénératives, UMR 5293, Bordeaux, France
| | - Antonio Pisani
- Laboratory of Neurophysiology and Plasticity, IRCCS Fondazione Santa Lucia, Rome, Italy .,Department of Systems Medicine, University Tor Vergata, Rome, Italy
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17
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Xu W, Reith MEA, Liu-Chen LY, Kortagere S. Biased signaling agonist of dopamine D3 receptor induces receptor internalization independent of β-arrestin recruitment. Pharmacol Res 2019; 143:48-57. [PMID: 30844536 DOI: 10.1016/j.phrs.2019.03.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 03/01/2019] [Accepted: 03/01/2019] [Indexed: 12/14/2022]
Abstract
Agonist-induced internalization of G protein-coupled receptors (GPCRs) is a significant step in receptor kinetics and is known to be involved in receptor down-regulation. However, the dopamine D3 receptor (D3R) has been an exception wherein agonist induces D3Rs to undergo desensitization followed by pharmacological sequestration - which is defined as the sequestration of cell surface receptors into a more hydrophobic fraction within the plasma membrane without undergoing the process of receptor internalization. Pharmacological sequestration renders the receptor in an inactive state on the membrane. In our previous study we demonstrated that a novel class of D3R agonists exemplified by SK608 have biased signaling properties via the G-protein dependent pathway and do not induce D3R desensitization. In this study, using radioligand binding assay, immunoblot or immunocytochemistry methods, we observed that SK608 induced internalization of human D3R stably expressed in CHO, HEK and SH-SY5Y cells which are derived from neuroblastoma cells, suggesting that it is not a cell-type specific event. Further, we have evaluated the potential mechanism of D3R internalization induced by these biased signaling agonists. SK608-induced D3R internalization was time- and concentration-dependent. In comparison, dopamine induced D3R upregulation and pharmacological sequestration in the same assays. GRK2 and clathrin/dynamin I/II are the key molecular players in the SK608-induced D3R internalization process, while β-arrestin 1/2 and GRK-interacting protein 1(GIT1) are not involved. These results suggest that SK608-promoted D3R internalization is similar to the type II internalization observed among peptide binding GPCRs.
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Affiliation(s)
- Wei Xu
- Department of Microbiology and Immunology, Drexel University College of Medicine, PA 19129, United States
| | - Maarten E A Reith
- Department of Psychiatry, Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY 10016, United States
| | - Lee-Yuan Liu-Chen
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140, United States
| | - Sandhya Kortagere
- Department of Microbiology and Immunology, Drexel University College of Medicine, PA 19129, United States; Department of Pharmacology and Physiology, Drexel University College of Medicine, PA 19102, United States.
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18
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Kumar GA, Sarkar P, Jafurulla M, Singh SP, Srinivas G, Pande G, Chattopadhyay A. Exploring Endocytosis and Intracellular Trafficking of the Human Serotonin1A Receptor. Biochemistry 2019; 58:2628-2641. [DOI: 10.1021/acs.biochem.9b00033] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- G. Aditya Kumar
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
| | - Parijat Sarkar
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
| | - Md. Jafurulla
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
| | - Shishu Pal Singh
- National Centre for Biological Sciences, UAS-GKVK Campus, Bellary Road, Bangalore 560 065, India
| | - Gunda Srinivas
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
| | - Gopal Pande
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
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19
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New Binding Sites, New Opportunities for GPCR Drug Discovery. Trends Biochem Sci 2019; 44:312-330. [PMID: 30612897 DOI: 10.1016/j.tibs.2018.11.011] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2018] [Revised: 08/11/2018] [Accepted: 11/27/2018] [Indexed: 12/29/2022]
Abstract
Many central biological events rely on protein-ligand interactions. The identification and characterization of protein-binding sites for ligands are crucial for the understanding of functions of both endogenous ligands and synthetic drug molecules. G protein-coupled receptors (GPCRs) typically detect extracellular signal molecules on the cell surface and transfer these chemical signals across the membrane, inducing downstream cellular responses via G proteins or β-arrestin. GPCRs mediate many central physiological processes, making them important targets for modern drug discovery. Here, we focus on the most recent breakthroughs in finding new binding sites and binding modes of GPCRs and their potentials for the development of new medicines.
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20
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Park M, Reddy GR, Wallukat G, Xiang YK, Steinberg SF. β 1-adrenergic receptor O-glycosylation regulates N-terminal cleavage and signaling responses in cardiomyocytes. Sci Rep 2017; 7:7890. [PMID: 28801655 PMCID: PMC5554155 DOI: 10.1038/s41598-017-06607-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 06/15/2017] [Indexed: 11/09/2022] Open
Abstract
β1-adrenergic receptors (β1ARs) mediate catecholamine actions in cardiomyocytes by coupling to both Gs/cAMP-dependent and Gs-independent/growth-regulatory pathways. Structural studies of the β1AR define ligand-binding sites in the transmembrane helices and effector docking sites at the intracellular surface of the β1AR, but the extracellular N-terminus, which is a target for post-translational modifications, typically is ignored. This study identifies β1AR N-terminal O-glycosylation at Ser37/Ser41 as a mechanism that prevents β1AR N-terminal cleavage. We used an adenoviral overexpression strategy to show that both full-length/glycosylated β1ARs and N-terminally truncated glycosylation-defective β1ARs couple to cAMP and ERK-MAPK signaling pathways in cardiomyocytes. However, a glycosylation defect that results in N-terminal truncation stabilizes β1ARs in a conformation that is biased toward the cAMP pathway. The identification of O-glycosylation and N-terminal cleavage as novel structural determinants of β1AR responsiveness in cardiomyocytes could be exploited for therapeutic advantage.
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Affiliation(s)
- Misun Park
- Department of Pharmacology, Columbia University, New York, NY, USA
| | - Gopireddy R Reddy
- Department of Pharmacology, University of California at Davis, Davis, CA, USA
| | - Gerd Wallukat
- Experimental and Clinical Research Center, Charité Campus Buch and Max-Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Yang K Xiang
- Department of Pharmacology, University of California at Davis, Davis, CA, USA.,VA Northern California Health Care System, Mather, CA, USA
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21
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Ligand binding pocket of a novel Allatostatin receptor type C of stick insect, Carausius morosus. Sci Rep 2017; 7:41266. [PMID: 28117376 PMCID: PMC5259779 DOI: 10.1038/srep41266] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 12/19/2016] [Indexed: 02/03/2023] Open
Abstract
Allatostatins (AST) are neuropeptides with variable function ranging from regulation of developmental processes to the feeding behavior in insects. They exert their effects by binding to cognate GPCRs, called Allatostatin receptors (AlstR), which emerge as promising targets for pesticide design. However, AlstRs are rarely studied. This study is the first reported structural study on AlstR-AST interaction. In this work, the first C type AlstR from the stick insect Carausius morosus (CamAlstR-C) was identified and its interaction with type C AST peptide was shown to be physically consistent with the experimental results. The proposed structure of CamAlstR-C revealed a conserved motif within the third extracellular loop, which, together with the N-terminus is essential for ligand binding. In this work, computational studies were combined with molecular and nano-scale approaches in order to introduce an unknown GPCR-ligand system. Consequently, the data obtained provided a reliable target region for future agonist/inverse agonist studies on AlstRs.
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22
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Sinmaz N, Tea F, Pilli D, Zou A, Amatoury M, Nguyen T, Merheb V, Ramanathan S, Cooper ST, Dale RC, Brilot F. Dopamine-2 receptor extracellular N-terminus regulates receptor surface availability and is the target of human pathogenic antibodies from children with movement and psychiatric disorders. Acta Neuropathol Commun 2016; 4:126. [PMID: 27908295 PMCID: PMC5134269 DOI: 10.1186/s40478-016-0397-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 11/23/2016] [Indexed: 12/17/2022] Open
Abstract
Anti-Dopamine-2 receptor (D2R) antibodies have been recently identified in a subgroup of children with autoimmune movement and psychiatric disorders, however the epitope(s) and mechanism of pathogenicity remain unknown. Here we report a major biological role for D2R extracellular N-terminus as a regulator of receptor surface availability, and as a major epitope targeted and impaired in brain autoimmunity. In transfected human cells, purified anti-D2R antibody from patients specifically and significantly reduced human D2R surface levels. Next, human D2R mutants modified in their extracellular domains were subcloned, and we analyzed the region bound by 35 anti-D2R antibody-positive patient sera using quantitative flow cytometry on live transfected cells. We found that N-glycosylation at amino acids N5 and/or N17 was critical for high surface expression in interaction with the last 15 residues of extracellular D2R N-terminus. No anti-D2R antibody-positive patient sera bound to the three extracellular loops, but all patient sera (35/35) targeted the extracellular N-terminus. Overall, patient antibody binding was dependent on two main regions encompassing amino acids 20 to 29, and 23 to 37. Residues 20 to 29 contributed to the majority of binding (77%, 27/35), among which 26% (7/27) sera bound to amino acids R20, P21, and F22, 37% (10/27) patients were dependent on residues at positions 26 and 29, that are different between humans and mice, and 30% (8/27) sera required R20, P21, F22, N23, D26, and A29. Seven patient sera bound to the region 23 to 37 independently of D26 and A29, but most sera exhibited N-glycosylation-independent epitope recognition at N23. Interestingly, no evident segregation of binding pattern according to patient clinical phenotype was observed. D2R N-terminus is a central epitope in autoimmune movement and psychiatric disorders and this knowledge could help the design of novel specific immune therapies tailored to improve patient outcome.
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23
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The N-terminus of the yeast G protein-coupled receptor Ste2p plays critical roles in surface expression, signaling, and negative regulation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1858:715-24. [PMID: 26707753 DOI: 10.1016/j.bbamem.2015.12.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 11/18/2015] [Accepted: 12/15/2015] [Indexed: 12/23/2022]
Abstract
G protein-coupled receptors (GPCRs) are found in all eukaryotic cells examined to date where they function as membrane-bound proteins that bind a multitude of extracellular ligands to initiate intracellular signal transduction systems controlling cellular physiology. GPCRs have seven heptahelical membrane spanning domains connected by extracellular and intracellular loops with an extracellular N-terminus and an intracellular C-terminus. The N-terminus has been the least studied domain of most GPCRs. The yeast Ste2p protein, the receptor for the thirteen amino acid peptide pheromone α-factor, has been used extensively as a model to study GPCR structure and function. In this study we constructed a number of deletions of the Ste2p N-terminus and uncovered an unexpected function as a negative regulatory domain. We examined the role of the N-terminus in expression, signaling function and ligand-binding properties and found that the residues 11-30 play a critical role in receptor expression on the cell surface. The studies also indicated that residues 2-10 of the N-terminus are involved in negative regulation of signaling as shown by the observation that deletion of these residues enhanced mating and gene induction. Furthermore, our results indicated that the residues 21-30 are essential for optimal signaling. Overall, we propose that the N-terminus of Ste2p plays multiple regulatory roles in controlling receptor function.
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24
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Lys39-Lysophosphatidate Carbonyl Oxygen Interaction Locks LPA1 N-terminal Cap to the Orthosteric Site and partners Arg124 During Receptor Activation. Sci Rep 2015; 5:13343. [PMID: 26268898 PMCID: PMC4542628 DOI: 10.1038/srep13343] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 07/21/2015] [Indexed: 12/21/2022] Open
Abstract
Lysophosphatidic acid (LPA) receptor 1 (LPA1) is a member of the G protein-coupled receptors mediating the biological response to LPA species. Lack of detailed mechanism underlying LPA/LPA1 interaction has hampered the development of specific antagonists. Here, novel N-terminal Lys39 has been identified as a key residue during LPA-type agonist binding and LPA1 activation. Analysis of the molecular dynamics (MD) trajectories showed that LPA-type agonist but not VPC-32183 (antagonist) evolved structures with classical GPCR activation signatures such as reduced cytoplasmic transmembrane (TM) 3/TM6 dynamic network, ruptured ionic lock, and formation of a continuous and highly ordered internal water pathway was also observed. In activated state, LPA-type agonists interact with Arg124 (R3.28), Gln125 (Q3.29), Lys294 (K7.36) and a novel N-terminal Lys39. Site-directed mutagenesis showed complete loss of intracellular calcium mobilization in B103 cells expressing R3.28A and Lys39Ala when treated with LPA-type agonists. Structurally, LPA-type agonist via Carbonyl-oxygen/Lys39 interaction facilitated the formation of a hypothetical N-terminal cap tightly packed over LPA1 heptahelical bundle. This packing may represent a key mechanism to distinguish an apo-receptor from bound LPA1.
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25
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Guo S, Zhang X, Zheng M, Zhang X, Min C, Wang Z, Cheon SH, Oak MH, Nah SY, Kim KM. Selectivity of commonly used inhibitors of clathrin-mediated and caveolae-dependent endocytosis of G protein-coupled receptors. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:2101-10. [PMID: 26055893 DOI: 10.1016/j.bbamem.2015.05.024] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 05/23/2015] [Accepted: 05/30/2015] [Indexed: 12/15/2022]
Abstract
Among the multiple G protein-coupled receptor (GPCR) endocytic pathways, clathrin-mediated endocytosis (CME) and caveolar endocytosis are more extensively characterized than other endocytic pathways. A number of endocytic inhibitors have been used to block CME; however, systemic studies to determine the selectivity of these inhibitors are needed. Clathrin heavy chain or caveolin1-knockdown cells have been employed to determine the specificity of various chemical and molecular biological tools for CME and caveolar endocytosis. Sucrose, concanavalin A, and dominant negative mutants of dynamin blocked other endocytic pathways, in addition to CME. In particular, concanavalin A nonspecifically interfered with the signaling of several GPCRs tested in the study. Decreased pH, monodansylcadaverine, and dominant negative mutants of epsin were more specific for CME than other treatments were. A recently introduced CME inhibitor, Pitstop2™, showed only marginal selectivity for CME and interfered with receptor expression on the cell surface. Blockade of receptor endocytosis by epsin mutants and knockdown of the clathrin heavy chain enhanced the β2AR-mediated ERK activation. Overall, our studies show that previous experimental results should be interpreted with discretion if they included the use of endocytic inhibitors that were previously thought to be CME-selective. In addition, our study shows that endocytosis of β2 adrenoceptor through clathrin-mediated pathway has negative effects on ERK activation.
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Affiliation(s)
- Shuohan Guo
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju 500-757, Republic of Korea
| | - Xiaohan Zhang
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju 500-757, Republic of Korea
| | - Mei Zheng
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju 500-757, Republic of Korea
| | - Xiaowei Zhang
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju 500-757, Republic of Korea
| | - Chengchun Min
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju 500-757, Republic of Korea
| | - Zengtao Wang
- Department of Medicinal Chemistry, College of Pharmacy, Chonnam National University, Gwang-Ju 500-757, Republic of Korea
| | - Seung Hoon Cheon
- Department of Medicinal Chemistry, College of Pharmacy, Chonnam National University, Gwang-Ju 500-757, Republic of Korea
| | - Min-Ho Oak
- College of Pharmacy, Mokpo National University, Muan-gun, Jeollanamdo 534-729, Republic of Korea
| | - Seung-Yeol Nah
- Department of Physiology, College of Veterinary Medicine and Bio/Molecular Informatics Center, Konkuk University, Seoul 143-701, Republic of Korea
| | - Kyeong-Man Kim
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju 500-757, Republic of Korea.
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26
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Min C, Zheng M, Zhang X, Caron MG, Kim KM. Novel roles for β-arrestins in the regulation of pharmacological sequestration to predict agonist-induced desensitization of dopamine D3 receptors. Br J Pharmacol 2014; 170:1112-29. [PMID: 23992580 DOI: 10.1111/bph.12357] [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] [Received: 03/11/2013] [Revised: 07/24/2013] [Accepted: 08/18/2013] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE In addition to typical GPCR kinase (GRK)-/β-arrestin-dependent internalization, dopamine D3 receptor employed an additional GRK-independent sequestration pathway. In this study, we investigated the molecular mechanism of this novel sequestration pathway. EXPERIMENTAL APPROACH Radioligand binding, flow cytometry and cell surface biotinylation assay were used to characterize trafficking properties of D2 and D3 receptors. Serine/threonine and N-linked glycosylation mutants of the D3 receptor were utilized to locate receptor regions involved in pharmacological sequestration and desensitization. Various point mutants of the D2 and D3 receptors, whose sequestration and desensitization properties were altered, were combined with knockdown cells of GRKs or β-arrestins to functionally correlate pharmacological sequestration and desensitization. KEY RESULTS The D3 receptor, but not the D2 receptor, showed characteristic trafficking behaviour in which receptors were shifted towards the more hydrophobic domains within the plasma membrane without translocation into other intracellular compartments. Among various amino acid residues tested, S145/S146, C147 and N12/19 were involved in pharmacological sequestration and receptor desensitization. Both pharmacological sequestration and desensitization of D3 receptor required β-arrestins, and functional relationship was observed between two processes when it was tested for D3 receptor variants and agonists. CONCLUSIONS AND IMPLICATIONS Pharmacological sequestration of D3 receptor accompanies movement of cell surface receptors into a more hydrophobic fraction within the plasma membrane and renders D3 receptor inaccessible to hydrophilic ligands. Pharmacological sequestration is correlated with desensitization of the D3 receptor in a Gβγ- and β-arrestin-dependent manner. This study provides new insights into molecular mechanism governing GPCR trafficking and desensitization.
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Affiliation(s)
- C Min
- Department of Pharmacology, College of Pharmacy, Drug Development Research Institute, Chonnam National University, Gwang-Ju, 500-757, Korea
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Single and binge methamphetamine administrations have different effects on the levels of dopamine D2 autoreceptor and dopamine transporter in rat striatum. Int J Mol Sci 2014; 15:5884-906. [PMID: 24717411 PMCID: PMC4013602 DOI: 10.3390/ijms15045884] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 03/15/2014] [Accepted: 03/25/2014] [Indexed: 01/17/2023] Open
Abstract
Methamphetamine (METH) is a central nervous system psychostimulant with a high potential for abuse. At high doses, METH causes a selective degeneration of dopaminergic terminals in the striatum. Dopamine D2 receptor antagonists and dopamine transporter (DAT) inhibitors protect against neurotoxicity of the drug by decreasing intracellular dopamine content and, consequently, dopamine autoxidation and production of reactive oxygen species. In vitro, amphetamines regulate D2 receptor and DAT functions via regulation of their intracellular trafficking. No data exists on axonal transport of both proteins and there is limited data on their interactions in vivo. The aim of the present investigation was to examine synaptosomal levels of presynaptic D2 autoreceptor and DAT after two different regimens of METH and to determine whether METH affects the D2 autoreceptor-DAT interaction in the rat striatum. We found that, as compared to saline controls, administration of single high-dose METH decreased D2 autoreceptor immunoreactivity and increased DAT immunoreactivity in rat striatal synaptosomes whereas binge high-dose METH increased immunoreactivity of D2 autoreceptor and had no effect on DAT immunoreactivity. Single METH had no effect on D2 autoreceptor-DAT interaction whereas binge METH increased the interaction between the two proteins in the striatum. Our results suggest that METH can affect axonal transport of both the D2 autoreceptor and DAT in an interaction-dependent and -independent manner.
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Greer AM, Wu N, Putnam AL, Woodruff PG, Wolters P, Kinet JP, Shin JS. Serum IgE clearance is facilitated by human FcεRI internalization. J Clin Invest 2014; 124:1187-98. [PMID: 24569373 DOI: 10.1172/jci68964] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Accepted: 12/12/2013] [Indexed: 11/17/2022] Open
Abstract
The high-affinity IgE receptor FcεRI is constitutively expressed in mast cells and basophils and is required for transmitting stimulatory signals upon engagement of IgE-bound allergens. FcεRI is also constitutively expressed in dendritic cells (DCs) and monocytes in humans; however, the specific functions of the FcεRI expressed by these cells are not completely understood. Here, we found that FcεRI expressed by human blood DC antigen 1-positive (BDCA1+) DCs and monocytes, but not basophils, traffics to endolysosomal compartments under steady-state conditions. Furthermore, IgE bound to FcεRI on BDCA1+ DCs was rapidly endocytosed, transported to the lysosomes, and degraded in vitro. IgE injected into mice expressing human FcεRIα (FCER1A-Tg mice) was endocytosed by conventional DCs and monocytes, and endocytosis was associated with rapid clearance of circulating IgE from these mice. Importantly, this rapid IgE clearance was dependent on monocytes or DCs but not basophils. These findings strongly suggest that constitutive internalization of human FcεRI by DCs and monocytes distinctively contributes to serum IgE clearance.
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Amatoury M, Merheb V, Langer J, Wang XM, Dale RC, Brilot F. High-throughput flow cytometry cell-based assay to detect antibodies to N-methyl-D-aspartate receptor or dopamine-2 receptor in human serum. J Vis Exp 2013:e50935. [PMID: 24300941 DOI: 10.3791/50935] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Over the recent years, antibodies against surface and conformational proteins involved in neurotransmission have been detected in autoimmune CNS diseases in children and adults. These antibodies have been used to guide diagnosis and treatment. Cell-based assays have improved the detection of antibodies in patient serum. They are based on the surface expression of brain antigens on eukaryotic cells, which are then incubated with diluted patient sera followed by fluorochrome-conjugated secondary antibodies. After washing, secondary antibody binding is then analyzed by flow cytometry. Our group has developed a high-throughput flow cytometry live cell-based assay to reliably detect antibodies against specific neurotransmitter receptors. This flow cytometry method is straight forward, quantitative, efficient, and the use of a high-throughput sampler system allows for large patient cohorts to be easily assayed in a short space of time. Additionally, this cell-based assay can be easily adapted to detect antibodies to many different antigenic targets, both from the central nervous system and periphery. Discovering additional novel antibody biomarkers will enable prompt and accurate diagnosis and improve treatment of immune-mediated disorders.
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Affiliation(s)
- Mazen Amatoury
- Institute for Neuroscience and Muscle Research, The Kids Research Institute at the Children's Hospital at Westmead, The University of Sydney
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Cho DI, Zheng M, Min C, Kwon KJ, Shin CY, Choi HK, Kim KM. ARF6 and GASP-1 are post-endocytic sorting proteins selectively involved in the intracellular trafficking of dopamine D₂ receptors mediated by GRK and PKC in transfected cells. Br J Pharmacol 2013; 168:1355-74. [PMID: 23082996 PMCID: PMC3596642 DOI: 10.1111/bph.12025] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 09/07/2012] [Accepted: 09/28/2012] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE GPCRs undergo both homologous and heterologous regulatory processes in which receptor phosphorylation plays a critical role. The protein kinases responsible for each pathway are well established; however, other molecular details that characterize each pathway remain unclear. In this study, the molecular mechanisms that determine the differences in the functional roles and intracellular trafficking between homologous and PKC-mediated heterologous internalization pathways for the dopamine D₂ receptor were investigated. EXPERIMENTAL APPROACH All of the S/T residues located within the intracellular loops of D₂ receptor were mutated, and the residues responsible for GRK- and PKC-mediated internalization were determined in HEK-293 cells and SH-SY5Y cells. The functional role of receptor internalization and the cellular components that determine the post-endocytic fate of internalized D₂ receptors were investigated in the transfected cells. KEY RESULTS T134, T225/S228/S229 and S325 were involved in PKC-mediated D₂ receptor desensitization. S229 and adjacent S/T residues mediated the PKC-dependent internalization of D₂ receptors, which induced down-regulation and desensitization. S/T residues within the second intracellular loop and T225 were the major residues involved in GRK-mediated internalization of D₂ receptors, which induced receptor resensitization. ARF6 mediated the recycling of D₂ receptors internalized in response to agonist stimulation. In contrast, GASP-1 mediated the down-regulation of D₂ receptors internalized in a PKC-dependent manner. CONCLUSIONS AND IMPLICATIONS GRK- and PKC-mediated internalizations of D₂ receptors occur through different intracellular trafficking pathways and mediate distinct functional roles. Distinct S/T residues within D₂ receptors and different sorting proteins are involved in the dissimilar regulation of D₂ receptors by GRK2 and PKC.
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Affiliation(s)
- D I Cho
- Department of Pharmacology, College of Pharmacy, Drug Development Research Institute, Chonnam National University, Gwang-Ju, Korea
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