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Morioka N, Nakamura Y, Hisaoka-Nakashima K, Nakata Y. High mobility group box-1: A therapeutic target for analgesia and associated symptoms in chronic pain. Biochem Pharmacol 2024; 222:116058. [PMID: 38367818 DOI: 10.1016/j.bcp.2024.116058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 01/16/2024] [Accepted: 02/12/2024] [Indexed: 02/19/2024]
Abstract
The number of patients with chronic pain continues to increase against the background of an ageing society and a high incidence of various epidemics and disasters. One factor contributing to this situation is the absence of truly effective analgesics. Chronic pain is a persistent stress for the organism and can trigger a variety of neuropsychiatric symptoms. Hence, the search for useful analgesic targets is currently being intensified worldwide, and it is anticipated that the key to success may be molecules involved in emotional as well as sensory systems. High mobility group box-1 (HMGB1) has attracted attention as a therapeutic target for a variety of diseases. It is a very unique molecule having a dual role as a nuclear protein while also functioning as an inflammatory agent outside the cell. In recent years, numerous studies have shown that HMGB1 acts as a pain inducer in primary sensory nerves and the spinal dorsal horn. In addition, HMGB1 can function in the brain, and is involved in the symptoms of depression, anxiety and cognitive dysfunction that accompany chronic pain. In this review, we will summarize recent research and discuss the potential of HMGB1 as a useful drug target for chronic pain.
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Affiliation(s)
- Norimitsu Morioka
- Department of Pharmacology, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan.
| | - Yoki Nakamura
- Department of Pharmacology, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Kazue Hisaoka-Nakashima
- Department of Pharmacology, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | - Yoshihiro Nakata
- Department of Pharmacology, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
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2
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Liu H, Acharya S, Sudan SK, Hu L, Wu C, Cao Y, Li H, Zhang X. Comparative study of the molecular mechanisms underlying the G protein and β-arrestin-dependent pathways that lead to ERKs activation upon stimulation by dopamine D 2 receptor. FEBS J 2023; 290:5204-5233. [PMID: 37531324 DOI: 10.1111/febs.16921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 06/09/2023] [Accepted: 08/01/2023] [Indexed: 08/04/2023]
Abstract
Dopamine D2 receptor (D2 R) has been shown to activate extracellular signal-regulated kinases (ERKs) via distinct pathways dependent on either G-protein or β-arrestin. However, there has not been a systematic study of the regulatory process of D2 R-mediated ERKs activation by G protein- versus β-arrestin-dependent signaling since D2 R stimulation of ERKs reflects the simultaneous action of both pathways. Here, we investigated that differential regulation of D2 R-mediated ERKs activation via these two pathways. Our results showed that G protein-dependent ERKs activation was transient, rapid, reached maximum level at around 2 min, and importantly, the activated ERKs were entirely confined to the cytoplasm. In contrast, β-arrestin-dependent ERKs activation was more sustained, slower, reached maximum level at around 10 min, and phosphorylated ERKs translocated into the nucleus. Src was found to be commonly involved in both the G protein- and β-arrestin-dependent pathway-mediated ERKs activation. Pertussis toxin Gi/o inhibitor, GRK2-CT, AG1478 epidermal growth factor receptor inhibitor, and wortmannin phosphoinositide 3-kinase inhibitor all blocked G protein-dependent ERKs activation. In contrast, GRK2 and β-Arr2 played a main role in β-arrestin-dependent ERKs activation. Receptor endocytosis showed minimal effect on the activation of ERKs mediated by both pathways. Furthermore, we found that the formation of a complex composed of phospho-ERKs, β-Arr2, and importinβ1 promoted the nuclear translocation of activated ERKs. The differential regulation of various cellular components, as well as temporal and spatial patterns of ERKs activation via these two pathways, suggest the existence of distinct physiological outcomes.
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Affiliation(s)
- Haiping Liu
- School of Pharmaceutical Sciences, Guizhou University, Guiyang, China
| | - Srijan Acharya
- Mitchell Cancer Institute, School of Medicine, University of South Alabama, Mobile, AL, USA
| | - Sarabjeet Kour Sudan
- Mitchell Cancer Institute, School of Medicine, University of South Alabama, Mobile, AL, USA
| | - Li Hu
- School of Pharmaceutical Sciences, Guizhou University, Guiyang, China
| | - Chengyan Wu
- School of Pharmaceutical Sciences, Guizhou University, Guiyang, China
| | - Yongkai Cao
- Institute of Translational Medicine, The First Affiliated Hospital of Shenzhen University, China
| | - Huijun Li
- Department of Pharmaceuticals, People's Hospital of Zunyi City Bo Zhou District, China
| | - Xiaohan Zhang
- School of Pharmaceutical Sciences, Guizhou University, Guiyang, China
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3
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Dong X, Chen Y, Lu J, Huang S, Pei G. β-arrestin 2 and Epac2 cooperatively mediate DRD1-stimulated proliferation of human neural stem cells and growth of human cerebral organoids. Stem Cells 2022; 40:857-869. [PMID: 35772103 DOI: 10.1093/stmcls/sxac046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 06/15/2022] [Indexed: 11/12/2022]
Abstract
G protein coupled receptors (GPCRs) reportedly relay specific signals, such as dopamine and serotonin, to regulate neurogenic processes though the underlying signaling pathways are not fully elucidated. Based on our previous work which demonstrated Dopamine receptor D1 (DRD1) effectively induces the proliferation of human neural stem cells, here we continued to show the knockout of β-arrestin 2 by CRISPR/Cas9 technology significantly weakened the DRD1-induced proliferation and neurosphere growth. Furthermore, inhibition of the downstream p38 MAPK by its specific inhibitors or small hairpin RNA mimicked the weakening effect of β-arrestin 2 knockout. In addition, blocking of Epac2, a PKA independent signal pathway, by its specific inhibitors or small hairpin RNA also significantly reduced DRD1-induced effects. Simultaneous inhibition of β-arrestin 2/p38 MAPK and Epac2 pathways nearly abolished the DRD1-stimulated neurogenesis, indicating the cooperative contribution of both pathways. Consistently, the expansion and folding of human cerebral organoids as stimulated by DRD1 were also mediated cooperatively by both β-arrestin 2/p38 MAPK and Epac2 pathways. Taken together, our results reveal that GPCRs apply at least two different signal pathways to regulate neurogenic processes in a delicate and balanced manners.
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Affiliation(s)
- Xiaoxu Dong
- School of Life Science and Technology, Shanghai Tech University, Shanghai, China.,State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Yujie Chen
- Uli Schwarz Quantitative Biology Core Facility, Bio-Med Big Data Center, CAS Key Laboratory of Computational Biology, Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, Shanghai, China
| | - Juan Lu
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Shichao Huang
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Gang Pei
- School of Life Science and Technology, Shanghai Tech University, Shanghai, China.,State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China.,Shanghai Key Laboratory of Signaling and Disease Research, Collaborative Innovation Center for Brain Science, School of Life Sciences and Technology, Tongji University, Shanghai, China.,Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China
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4
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Kim K, Han Y, Duan L, Chung KY. Scaffolding of Mitogen-Activated Protein Kinase Signaling by β-Arrestins. Int J Mol Sci 2022; 23:ijms23021000. [PMID: 35055186 PMCID: PMC8778048 DOI: 10.3390/ijms23021000] [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] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 01/14/2022] [Accepted: 01/15/2022] [Indexed: 12/19/2022] Open
Abstract
β-arrestins were initially identified to desensitize and internalize G-protein-coupled receptors (GPCRs). Receptor-bound β-arrestins also initiate a second wave of signaling by scaffolding mitogen-activated protein kinase (MAPK) signaling components, MAPK kinase kinase, MAPK kinase, and MAPK. In particular, β-arrestins facilitate ERK1/2 or JNK3 activation by scaffolding signal cascade components such as ERK1/2-MEK1-cRaf or JNK3-MKK4/7-ASK1. Understanding the precise molecular and structural mechanisms of β-arrestin-mediated MAPK scaffolding assembly would deepen our understanding of GPCR-mediated MAPK activation and provide clues for the selective regulation of the MAPK signaling cascade for therapeutic purposes. Over the last decade, numerous research groups have attempted to understand the molecular and structural mechanisms of β-arrestin-mediated MAPK scaffolding assembly. Although not providing the complete mechanism, these efforts suggest potential binding interfaces between β-arrestins and MAPK signaling components and the mechanism for MAPK signal amplification by β-arrestin-mediated scaffolding. This review summarizes recent developments of cellular and molecular works on the scaffolding mechanism of β-arrestin for MAPK signaling cascade.
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Scaffolding mechanism of arrestin-2 in the cRaf/MEK1/ERK signaling cascade. Proc Natl Acad Sci U S A 2021; 118:2026491118. [PMID: 34507982 DOI: 10.1073/pnas.2026491118] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/28/2021] [Indexed: 01/14/2023] Open
Abstract
Arrestins were initially identified for their role in homologous desensitization and internalization of G protein-coupled receptors. Receptor-bound arrestins also initiate signaling by interacting with other signaling proteins. Arrestins scaffold MAPK signaling cascades, MAPK kinase kinase (MAP3K), MAPK kinase (MAP2K), and MAPK. In particular, arrestins facilitate ERK1/2 activation by scaffolding ERK1/2 (MAPK), MEK1 (MAP2K), and Raf (MAPK3). However, the structural mechanism underlying this scaffolding remains unknown. Here, we investigated the mechanism of arrestin-2 scaffolding of cRaf, MEK1, and ERK2 using hydrogen/deuterium exchange-mass spectrometry, tryptophan-induced bimane fluorescence quenching, and NMR. We found that basal and active arrestin-2 interacted with cRaf, while only active arrestin-2 interacted with MEK1 and ERK2. The ATP binding status of MEK1 or ERK2 affected arrestin-2 binding; ATP-bound MEK1 interacted with arrestin-2, whereas only empty ERK2 bound arrestin-2. Analysis of the binding interfaces suggested that the relative positions of cRaf, MEK1, and ERK2 on arrestin-2 likely facilitate sequential phosphorylation in the signal transduction cascade.
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Mangmool S, Parichatikanond W, Kurose H. Therapeutic Targets for Treatment of Heart Failure: Focus on GRKs and β-Arrestins Affecting βAR Signaling. Front Pharmacol 2018; 9:1336. [PMID: 30538631 PMCID: PMC6277550 DOI: 10.3389/fphar.2018.01336] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 10/30/2018] [Indexed: 12/19/2022] Open
Abstract
Heart failure (HF) is a heart disease that is classified into two main types: HF with reduced ejection fraction (HFrEF) and HF with preserved ejection fraction (HFpEF). Both types of HF lead to significant risk of mortality and morbidity. Pharmacological treatment with β-adrenergic receptor (βAR) antagonists (also called β-blockers) has been shown to reduce the overall hospitalization and mortality rates and improve the clinical outcomes in HF patients with HFrEF but not HFpEF. Although, the survival rate of patients suffering from HF continues to drop, the management of HF still faces several limitations and discrepancies highlighting the need to develop new treatment strategies. Overstimulation of the sympathetic nervous system is an adaptive neurohormonal response to acute myocardial injury and heart damage, whereas prolonged exposure to catecholamines causes defects in βAR regulation, including a reduction in the amount of βARs and an increase in βAR desensitization due to the upregulation of G protein-coupled receptor kinases (GRKs) in the heart, contributing in turn to the progression of HF. Several studies show that myocardial GRK2 activity and expression are raised in the failing heart. Furthermore, β-arrestins play a pivotal role in βAR desensitization and, interestingly, can mediate their own signal transduction without any G protein-dependent pathway involved. In this review, we provide new insight into the role of GRKs and β-arrestins on how they affect βAR signaling regarding the molecular and cellular pathophysiology of HF. Additionally, we discuss the therapeutic potential of targeting GRKs and β-arrestins for the treatment of HF.
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Affiliation(s)
- Supachoke Mangmool
- Department of Pharmacology, Faculty of Pharmacy, Mahidol University, Bangkok, Thailand
| | | | - Hitoshi Kurose
- Department of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
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7
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Watson U, Jain R, Asthana S, Saini DK. Spatiotemporal Modulation of ERK Activation by GPCRs. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 338:111-140. [DOI: 10.1016/bs.ircmb.2018.02.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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8
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Chen M, Liu C, Wang M, Wang H, Zhang K, Zheng Y, Yu Z, Li X, Guo W, Li N, Meng Q. Clenbuterol Induces Cell Cycle Arrest in C2C12 Myoblasts by Delaying p27 Degradation through β-arrestin 2 Signaling. Int J Biol Sci 2017; 13:1341-1350. [PMID: 29104500 PMCID: PMC5666532 DOI: 10.7150/ijbs.17948] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 06/16/2017] [Indexed: 02/04/2023] Open
Abstract
β2-Adrenoceptor (β2-AR) agonists promote muscle growth. The aim of this study was to elucidate some effects of the selective β2-adrenoceptor agonist clenbuterol (CLB) on myoblast proliferation. We found that CLB induces cell cycle arrest in C2C12 myoblasts. This effect is partly due to the enhanced stability of p27, rather than the increased gene transcription via cAMP response element-binding protein (CREB). Specifically, CLB treatment enhanced the accumulation of p27 in the nucleus while depleting it from the cytosol via a mechanism that requires β2-AR. Surprisingly, p27 accumulation was not reversed by the protein kinase A (PKA) inhibitor H-89, but interestingly, was alleviated by the knockdown of β-arrestin 2. Thus, our work provides a basis for β2-AR agonists inhibit myoblasts proliferation through signaling via β2-AR, β-arrestin 2, and p27.
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Affiliation(s)
- Min Chen
- State Key Laboratory for Agrobiotechnology, China Agricultural University, Beijing 100193, China.,Guangxi Province Center for Disease Control and Prevention, Nanning 530028, China
| | - Chuncheng Liu
- State Key Laboratory for Agrobiotechnology, China Agricultural University, Beijing 100193, China
| | - Meng Wang
- State Key Laboratory for Agrobiotechnology, China Agricultural University, Beijing 100193, China
| | - Hong Wang
- State Key Laboratory for Agrobiotechnology, China Agricultural University, Beijing 100193, China
| | - Kuo Zhang
- State Key Laboratory for Agrobiotechnology, China Agricultural University, Beijing 100193, China
| | - Yu Zheng
- State Key Laboratory for Agrobiotechnology, China Agricultural University, Beijing 100193, China
| | - Zhengquan Yu
- State Key Laboratory for Agrobiotechnology, China Agricultural University, Beijing 100193, China
| | - Xiangdong Li
- State Key Laboratory for Agrobiotechnology, China Agricultural University, Beijing 100193, China
| | - Wei Guo
- Animal Science/Molecular Biology Bldg, University of Wyoming, Laramie WY82071, USA
| | - Ning Li
- State Key Laboratory for Agrobiotechnology, China Agricultural University, Beijing 100193, China
| | - Qingyong Meng
- State Key Laboratory for Agrobiotechnology, China Agricultural University, Beijing 100193, China.,Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Science, China Agricultural University
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9
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Mangmool S, Denkaew T, Parichatikanond W, Kurose H. β-Adrenergic Receptor and Insulin Resistance in the Heart. Biomol Ther (Seoul) 2017; 25:44-56. [PMID: 28035081 PMCID: PMC5207462 DOI: 10.4062/biomolther.2016.128] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 07/26/2016] [Accepted: 08/02/2016] [Indexed: 12/24/2022] Open
Abstract
Insulin resistance is characterized by the reduced ability of insulin to stimulate tissue uptake and disposal of glucose including cardiac muscle. These conditions accelerate the progression of heart failure and increase cardiovascular morbidity and mortality in patients with cardiovascular diseases. It is noteworthy that some conditions of insulin resistance are characterized by up-regulation of the sympathetic nervous system, resulting in enhanced stimulation of β-adrenergic receptor (βAR). Overstimulation of βARs leads to the development of heart failure and is associated with the pathogenesis of insulin resistance in the heart. However, pathological consequences of the cross-talk between the βAR and the insulin sensitivity and the mechanism by which βAR overstimulation promotes insulin resistance remain unclear. This review article examines the hypothesis that βARs overstimulation leads to induction of insulin resistance in the heart.
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Affiliation(s)
- Supachoke Mangmool
- Department of Pharmacology, Faculty of Pharmacy, Mahidol University, Bangkok 10400, Thailand.,Center of Excellence for Innovation in Drug Design and Discovery, Faculty of Pharmacy, Mahidol University, Bangkok 10400, Thailand
| | - Tananat Denkaew
- Department of Pharmacology, Faculty of Pharmacy, Mahidol University, Bangkok 10400, Thailand
| | | | - Hitoshi Kurose
- Department of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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10
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Jain R, Watson U, Saini DK. ERK activated by Histamine H1 receptor is anti-proliferative through spatial restriction in the cytosol. Eur J Cell Biol 2016; 95:623-634. [DOI: 10.1016/j.ejcb.2016.10.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Revised: 10/04/2016] [Accepted: 10/24/2016] [Indexed: 10/20/2022] Open
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Zhang FF, Morioka N, Abe H, Fujii S, Miyauchi K, Nakamura Y, Hisaoka-Nakashima K, Nakata Y. Stimulation of spinal dorsal horn β2-adrenergic receptor ameliorates neuropathic mechanical hypersensitivity through a reduction of phosphorylation of microglial p38 MAP kinase and astrocytic c-jun N-terminal kinase. Neurochem Int 2016; 101:144-155. [PMID: 27840124 DOI: 10.1016/j.neuint.2016.11.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 10/21/2016] [Accepted: 11/01/2016] [Indexed: 12/22/2022]
Abstract
The noradrenaline-adrenergic system has a crucial role in controlling nociceptive transduction at the spinal level. While α-adrenergic receptors are known to regulate nociceptive neurotransmitter release at the spinal presynaptic level, it is not entirely clear whether β-adrenergic receptors are involved in controlling pain transduction at the spinal level as well. The current study elucidated a role of β-adrenergic receptors in neuropathic pain in mice following a partial sciatic nerve ligation (PSNL). In addition, the cellular and intracellular signaling cascade induced by β-adrenergic receptors in neuropathic mice was elaborated. Intrathecal injection of isoproterenol (1 nmol), a nonselective β-adrenergic receptor agonist, briefly ameliorated hind paw mechanical hypersensitivity of PSNL mice. Isoproterenol's antinociceptive effect was mediated through β2-adrenergic receptors since pretreatment with ICI118551, a selective β2-adrenergic receptor antagonist, but not with CGP20712A, a selective β1-adrenergic receptor antagonist, significantly attenuated isoproterenol's effect. Furthermore, intrathecal treatment with a selective β2-adrenergic receptor agonist, terbutaline, but not a selective β1-adrenergic receptor agonist, dobutamine, also significantly ameliorated neuropathic pain. Fourteen days after PSNL, increased phosphorylation of both p38 Mitogen-activated protein kinase (MAPK) in microglia and c-jun N-terminal kinase (JNK) in astrocytes of ipsilateral spinal dorsal horn were observed. Phosphorylation of both microglial p38 MAPK and astrocytic JNK were downregulated by stimulation of the β2-adrenergic receptor. Together, these results suggest that spinal β2-adrenergic receptor have an inhibitory role in neuropathic nociceptive transduction at the spinal level through a downregulation of glial activity, perhaps through modulation of MAP kinases phosphorylation. Thus, targeting of β2-adrenergic receptors could be an effective therapeutic strategy in treating neuropathic pain.
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Affiliation(s)
- Fang Fang Zhang
- Department of Pharmacology, Hiroshima University Graduate School of Biomedical & Health Sciences, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan; Institute of Pharmacology, Taishan Medical University, 619 Changcheng Road, Taian, Shandong, 271016, China
| | - Norimitsu Morioka
- Department of Pharmacology, Hiroshima University Graduate School of Biomedical & Health Sciences, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan.
| | - Hiromi Abe
- Department of Pharmacology, Hiroshima University Graduate School of Biomedical & Health Sciences, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan
| | - Shiori Fujii
- Department of Pharmacology, Hiroshima University Graduate School of Biomedical & Health Sciences, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan
| | - Kazuki Miyauchi
- Department of Pharmacology, Hiroshima University Graduate School of Biomedical & Health Sciences, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan
| | - Yoki Nakamura
- Department of Pharmacology, Hiroshima University Graduate School of Biomedical & Health Sciences, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan
| | - Kazue Hisaoka-Nakashima
- Department of Pharmacology, Hiroshima University Graduate School of Biomedical & Health Sciences, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan
| | - Yoshihiro Nakata
- Department of Pharmacology, Hiroshima University Graduate School of Biomedical & Health Sciences, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan
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12
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Cattaneo F, Parisi M, Fioretti T, Sarnataro D, Esposito G, Ammendola R. Nuclear localization of Formyl-Peptide Receptor 2 in human cancer cells. Arch Biochem Biophys 2016; 603:10-9. [PMID: 27177968 DOI: 10.1016/j.abb.2016.05.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 05/06/2016] [Accepted: 05/06/2016] [Indexed: 12/20/2022]
Abstract
Current models of G protein-coupled receptors (GPCRs) signaling describe binding of external agonists to cell surface receptors which, in turn, trigger several biological responses. New paradigms indicate that GPCRs localize to and signal at the nucleus, thus regulating distinct signaling cascades. The formyl-peptide receptor FPR2 belongs to the GPCR super-family and is coupled to PTX-sensitive Gi proteins. We show by western blot analysis, immunofluorescence experiments and radioligand binding assays that FPR2 is expressed at nuclear level in CaLu-6 and AGS cells. Nuclear FPR2 is a functional receptor, since it participates in intra-nuclear signaling, as assessed by decreased G protein-FPR2 association and enhanced ERK2, c-Jun and c-Myc phosphorylation upon stimulation of intact nuclei with the FPR2 agonist, WKYMVm. We analyzed FPR2 sequence for the search of a nuclear localization sequence (NLS) and we found a stretch of basic aminoacids (227-KIHKK-231) in the third cytoplasmic loop of the receptor. We performed single (K230A) and multiple (H229A/K230A/K231A) mutagenesis of NLS. The constructs were individually overexpressed in HEK293 cells and immunofluorescence and western blot analysis showed that nuclear localization or translocation of FPR2 depends on the integrity of the H(229) and K(231) residues within the NLS.
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Affiliation(s)
- Fabio Cattaneo
- Department of Molecular Medicine and Medical Biotechnology, School of Medicine, University of Naples Federico II, Via S. Pansini 5, Naples 80131, Italy
| | - Melania Parisi
- Department of Molecular Medicine and Medical Biotechnology, School of Medicine, University of Naples Federico II, Via S. Pansini 5, Naples 80131, Italy
| | - Tiziana Fioretti
- Department of Molecular Medicine and Medical Biotechnology, School of Medicine, University of Naples Federico II, Via S. Pansini 5, Naples 80131, Italy; IRCCS SDN, Via E. Gianturco 113, Naples 80143, Italy
| | - Daniela Sarnataro
- Department of Molecular Medicine and Medical Biotechnology, School of Medicine, University of Naples Federico II, Via S. Pansini 5, Naples 80131, Italy; CEINGE-Biotecnologie Avanzate s.c.a.r.l., Via G. Salvatore 486, Naples 80145, Italy
| | - Gabriella Esposito
- Department of Molecular Medicine and Medical Biotechnology, School of Medicine, University of Naples Federico II, Via S. Pansini 5, Naples 80131, Italy; CEINGE-Biotecnologie Avanzate s.c.a.r.l., Via G. Salvatore 486, Naples 80145, Italy
| | - Rosario Ammendola
- Department of Molecular Medicine and Medical Biotechnology, School of Medicine, University of Naples Federico II, Via S. Pansini 5, Naples 80131, Italy.
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13
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Mu opioid receptor stimulation activates c-Jun N-terminal kinase 2 by distinct arrestin-dependent and independent mechanisms. Cell Signal 2015; 27:1799-806. [PMID: 26056051 DOI: 10.1016/j.cellsig.2015.05.019] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Accepted: 05/29/2015] [Indexed: 02/06/2023]
Abstract
G protein-coupled receptor desensitization is typically mediated by receptor phosphorylation by G protein-coupled receptor kinase (GRK) and subsequent arrestin binding; morphine, however, was previously found to activate a c-Jun N-terminal kinase (JNK)-dependent, GRK/arrestin-independent pathway to produce mu opioid receptor (MOR) inactivation in spinally-mediated, acute anti-nociceptive responses [Melief et al.] [1]. In the current study, we determined that JNK2 was also required for centrally-mediated analgesic tolerance to morphine using the hotplate assay. We compared JNK activation by morphine and fentanyl in JNK1(-/-), JNK2(-/-), JNK3(-/-), and GRK3(-/-) mice and found that both compounds specifically activate JNK2 in vivo; however, fentanyl activation of JNK2 was GRK3-dependent, whereas morphine activation of JNK2 was GRK3-independent. In MOR-GFP expressing HEK293 cells, treatment with either arrestin siRNA, the Src family kinase inhibitor PP2, or the protein kinase C (PKC) inhibitor Gö6976 indicated that morphine activated JNK2 through an arrestin-independent Src- and PKC-dependent mechanism, whereas fentanyl activated JNK2 through a Src-GRK3/arrestin-2-dependent and PKC-independent mechanism. This study resolves distinct ligand-directed mechanisms of JNK activation by mu opioid agonists and understanding ligand-directed signaling at MOR may improve opioid therapeutics.
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14
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Yang L, Zheng J, Xiong Y, Meng R, Ma Q, Liu H, Shen H, Zheng S, Wang S, He J. Regulation of β2-adrenergic receptor cell surface expression by interaction with cystic fibrosis transmembrane conductance regulator-associated ligand (CAL). Amino Acids 2015; 47:1455-64. [PMID: 25876703 DOI: 10.1007/s00726-015-1965-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Accepted: 03/13/2015] [Indexed: 10/23/2022]
Abstract
The beta-2 adrenergic receptor (β2AR), a member of GPCR, can activate multiple signaling pathways and is an important treatment target for cardiac failure. However, the molecular mechanism about β2AR signaling regulation is not fully understood. In this study, we found that cystic fibrosis transmembrane conductance regulator-associated ligand (CAL) overexpression reduced β2AR-mediated extracellular signal-regulated kinase-1/2 (ERK1/2) activation. Further study identified CAL as a novel binding partner of β2AR. CAL is associated with β2AR mainly via the third intracellular loop (ICL3) of receptor and the coiled-coil domains of CAL, which is distinct from CAL/β1AR interaction mediated by the carboxyl terminal (CT) of β1AR and PDZ domain of CAL. CAL overexpression retarded β2AR expression in Golgi apparatus and reduced the receptor expression in plasma membrane.
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Affiliation(s)
- Longyan Yang
- Department of Biochemistry and Molecular Biology, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing, 100069, People's Republic of China
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15
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Wang S, Gong H, Jiang G, Ye Y, Wu J, You J, Zhang G, Sun A, Komuro I, Ge J, Zou Y. Src is required for mechanical stretch-induced cardiomyocyte hypertrophy through angiotensin II type 1 receptor-dependent β-arrestin2 pathways. PLoS One 2014; 9:e92926. [PMID: 24699426 PMCID: PMC3974699 DOI: 10.1371/journal.pone.0092926] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Accepted: 02/26/2014] [Indexed: 01/14/2023] Open
Abstract
Angiotensin II (AngII) type 1 receptor (AT1-R) can be activated by mechanical stress (MS) without the involvement of AngII during the development of cardiomyocyte hypertrophy, in which G protein-independent pathways are critically involved. Although β-arrestin2-biased signaling has been speculated, little is known about how AT1-R/β-arrestin2 leads to ERK1/2 activation. Here, we present a novel mechanism by which Src kinase mediates AT1-R/β-arrestin2-dependent ERK1/2 phosphorylation in response to MS. Differing from stimulation by AngII, MS-triggered ERK1/2 phosphorylation is neither suppressed by overexpression of RGS4 (the negative regulator of the G-protein coupling signal) nor by inhibition of Gαq downstream protein kinase C (PKC) with GF109203X. The release of inositol 1,4,5-triphosphate (IP3) is increased by AngII but not by MS. These results collectively suggest that MS-induced ERK1/2 activation through AT1-R might be independent of G-protein coupling. Moreover, either knockdown of β-arrestin2 or overexpression of a dominant negative mutant of β-arrestin2 prevents MS-induced activation of ERK1/2. We further identifies a relationship between Src, a non-receptor tyrosine kinase and β-arrestin2 using analyses of co-immunoprecipitation and immunofluorescence after MS stimulation. Furthermore, MS-, but not AngII-induced ERK1/2 phosphorylation is attenuated by Src inhibition, which also significantly improves pressure overload-induced cardiac hypertrophy and dysfunction in mice lacking AngII. Finally, MS-induced Src activation and hypertrophic response are abolished by candesartan but not by valsartan whereas AngII-induced responses can be abrogated by both blockers. Our results suggest that Src plays a critical role in MS-induced cardiomyocyte hypertrophy through β-arrestin2-associated angiotensin II type 1 receptor signaling.
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MESH Headings
- Angiotensinogen/physiology
- Animals
- Animals, Newborn
- Arrestins/genetics
- Arrestins/metabolism
- Blotting, Western
- Cardiomegaly/metabolism
- Cardiomegaly/pathology
- Cells, Cultured
- Echocardiography
- Immunoenzyme Techniques
- Immunoprecipitation
- Inositol 1,4,5-Trisphosphate/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mitogen-Activated Protein Kinase 1/genetics
- Mitogen-Activated Protein Kinase 1/metabolism
- Mitogen-Activated Protein Kinase 3/genetics
- Mitogen-Activated Protein Kinase 3/metabolism
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/pathology
- Phosphorylation
- RNA, Messenger/genetics
- Rats
- Real-Time Polymerase Chain Reaction
- Receptor, Angiotensin, Type 1/genetics
- Receptor, Angiotensin, Type 1/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Signal Transduction
- Stress, Mechanical
- beta-Arrestins
- src-Family Kinases/genetics
- src-Family Kinases/metabolism
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Affiliation(s)
- Shijun Wang
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai, China; Institutes of Biomedical Science, Fudan University, Shanghai, China
| | - Hui Gong
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai, China; Institutes of Biomedical Science, Fudan University, Shanghai, China
| | - Guoliang Jiang
- Institutes of Biomedical Science, Fudan University, Shanghai, China
| | - Yong Ye
- Institutes of Biomedical Science, Fudan University, Shanghai, China
| | - Jian Wu
- Institutes of Biomedical Science, Fudan University, Shanghai, China
| | - Jieyun You
- Institutes of Biomedical Science, Fudan University, Shanghai, China
| | - Guoping Zhang
- Institutes of Biomedical Science, Fudan University, Shanghai, China
| | - Aijun Sun
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai, China; Institutes of Biomedical Science, Fudan University, Shanghai, China
| | - Issei Komuro
- Department of Cardiovascular Medicine, the University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Junbo Ge
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai, China; Institutes of Biomedical Science, Fudan University, Shanghai, China
| | - Yunzeng Zou
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai, China; Institutes of Biomedical Science, Fudan University, Shanghai, China
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16
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Tilley DG, Rockman HA. Role of β-adrenergic receptor signaling and desensitization in heart failure: new concepts and prospects for treatment. Expert Rev Cardiovasc Ther 2014; 4:417-32. [PMID: 16716102 DOI: 10.1586/14779072.4.3.417] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The use of beta-blockers to antagonize beta-adrenergic receptor signaling in the heart has become a standard method of treatment for heart failure, resulting in positive clinical outcomes alone and in conjunction with other modulators of cardiomyocyte contractility. However, an entire explanation for improved cardiac function in patients using beta-blockers is unknown, and in fact may be quite complicated, considering the numerous intracellular signaling pathways associated with beta-adrenergic receptors. Stimulation of beta-adrenergic receptors during both normal conditions and during heart failure activate several distinct signaling cascades, which influence cardiomyocyte contraction, hypertrophy and apoptosis. This review explores the signaling cascades induced by beta-adrenergic receptor activation in normal and desensitized states to provide new insight into the effective treatment of cardiac dysfunction.
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Affiliation(s)
- Douglas G Tilley
- Department of Medicine Duke University Medical Center Durham, NC 27710, USA.
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17
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Rietz A, Volkov Y, Davies A, Hennessy M, Spiers JP. Okadaic acid induces matrix metalloproteinase-9 expression in fibroblasts: crosstalk between protein phosphatase inhibition and β-adrenoceptor signalling. Br J Pharmacol 2012; 165:274-88. [PMID: 21718298 DOI: 10.1111/j.1476-5381.2011.01559.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND AND PURPOSE Interactions between protein phosphatase inhibition and matrix metalloproteinase (MMP)-9 expression have implications for tissue remodelling after injury. Stimulation of β-adrenoceptors could affect such interactions as isoprenaline increases protein phosphatase 2A (PP2A) activity and MMP-9 abundance. We investigated the effect of okadaic acid (OA) on MMP-9 expression to assess interactions between phosphatase inhibition and β-adrenoceptor signalling in fibroblasts. EXPERIMENTAL APPROACH Fibroblasts were exposed to OA alone and in combination with isoprenaline. Effects on MMP-9 expression and intracellular signalling were studied using promoter assays, Western blot analysis and siRNA methodologies. KEY RESULTS Okadaic acid increased MMP-9 abundance in human cardiac ventricular fibroblasts, NIH3T3 fibroblasts and hepatic stellate cells. This effect was unaffected by PP2A knockdown in NIH3T3 cells. OA increased phosphorylation of NF-κB, but not NF-κB promoter activity, IκBα degradation, or nuclear translocation of p65-NF-κB. Exposure to SB202190 (p38 MAPK), U0126 (ERK1/2) and NF-κB III inhibitor revealed that OA induced MMP-9 activity through p38 MAPK. Isoprenaline inhibited OA-mediated MMP-9 expression in NIH3T3, in a β-arrestin 2- and PP2A-dependent manner. Mutation of the activator protein-1 (AP-1) and NF-κB binding sites demonstrated that OA-induced MMP-9 activity was mediated through the AP-1 but not NF-κB sites. The latter mediated the inhibitory effect of isoprenaline on OA-induced MMP-9 promoter activity. CONCLUSION AND IMPLICATIONS Okadaic acid induced MMP-9 activity through p38 MAPK and was inhibited by isoprenaline via a pathway involving β-arrestin 2, PP2A and an NF-κB binding motif. These findings elucidate how phosphoprotein phosphatases and adrenoceptors may modulate tissue remodelling by affecting fibroblast function.
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Affiliation(s)
- A Rietz
- Department of Pharmacology and Therapeutics, Trinity College Dublin, Dublin, Ireland
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18
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Manson ME, Corey DA, Rymut SM, Kelley TJ. β-arrestin-2 regulation of the cAMP response element binding protein. Biochemistry 2011; 50:6022-9. [PMID: 21644508 DOI: 10.1021/bi200015h] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Previous work demonstrated that cystic fibrosis (CF) cells exhibit an increase in cAMP-mediated signaling as a characteristic response to lost CFTR function. Evidence for increased cAMP-mediated signaling in CF included increased phosphorylation of the cAMP response element binding protein (CREB) and elevated β-arrestin-2 (βarr2) expression. However, subsequent studies reveal that CREB activation in CF cells is independent of protein kinase-A (PKA). The goal of this study is to test the hypothesis that elevated βarr2 expression leads to increased CREB activation in a PKA-independent mechanism. βarr2-GFP expressing tracheal epithelial cells (βarr2-GFP) exhibit an increase of pCREB content and subsequent CRE activation compared to GFP expressing control cells. βarr2 activation of the ERK cascade represents a candidate mechanism leading to CREB activation. ERK exhibits increased activation in βarr2-GFP cells compared to cont-GFP cells, and ERK inhibition diminishes CRE activation in both GFP and βarr2-GFP cells. To test directly whether CREB regulation in CF is βarr2-dependent, nasal epithelium excised from wt mice (Cftr +/+; βarr2 +/+), CF mice (Cftr -/-; βarr2 +/+), and DKO mice (Cftr -/-; βarr2 -/-) were analyzed for pCREB protein content. Removal of βarr2 expression from CF mice reduces both pCREB and pERK content to wt levels. These data indicate that CF-related CREB regulation is mediated directly through βarr2 expression via the ERK pathway.
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Affiliation(s)
- Mary E Manson
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106-4948, USA
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19
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Zheng H, Chu J, Zhang Y, Loh HH, Law PY. Modulating micro-opioid receptor phosphorylation switches agonist-dependent signaling as reflected in PKCepsilon activation and dendritic spine stability. J Biol Chem 2011; 286:12724-33. [PMID: 21292762 DOI: 10.1074/jbc.m110.177089] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
A new role of G protein-coupled receptor (GPCR) phosphorylation was demonstrated in the current studies by using the μ-opioid receptor (OPRM1) as a model. Morphine induces a low level of receptor phosphorylation and uses the PKCε pathway to induce ERK phosphorylation and receptor desensitization, whereas etorphine, fentanyl, and [D-Ala2,N-Me-Phe4,Gly5-ol]-enkephalin (DAMGO) induce extensive receptor phosphorylation and use the β-arrestin2 pathway. Blocking OPRM1 phosphorylation (by mutating Ser363, Thr370 and Ser375 to Ala) enabled etorphine, fentanyl, and DAMGO to use the PKCε pathway. This was not due to the decreased recruitment of β-arrestin2 to the receptor signaling complex, because these agonists were unable to use the PKCε pathway when β-arrestin2 was absent. In addition, overexpressing G protein-coupled receptor kinase 2 (GRK2) decreased the ability of morphine to activate PKCε, whereas overexpressing dominant-negative GRK2 enabled etorphine, fentanyl, and DAMGO to activate PKCε. Furthermore, by overexpressing wild-type OPRM1 and a phosphorylation-deficient mutant in primary cultures of hippocampal neurons, we demonstrated that receptor phosphorylation contributes to the differential effects of agonists on dendritic spine stability. Phosphorylation blockage made etorphine, fentanyl, and DAMGO function as morphine in the primary cultures. Therefore, agonist-dependent phosphorylation of GPCR regulates the activation of the PKC pathway and the subsequent responses.
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Affiliation(s)
- Hui Zheng
- Department of Pharmacology, University of Minnesota, Minneapolis, Minnesota 55455-0217, USA.
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20
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Szereszewski JM, Pampillo M, Ahow MR, Offermanns S, Bhattacharya M, Babwah AV. GPR54 regulates ERK1/2 activity and hypothalamic gene expression in a Gα(q/11) and β-arrestin-dependent manner. PLoS One 2010; 5:e12964. [PMID: 20886089 PMCID: PMC2944883 DOI: 10.1371/journal.pone.0012964] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Accepted: 09/03/2010] [Indexed: 01/14/2023] Open
Abstract
G protein-coupled receptor 54 (GPR54) is a Gq/11-coupled 7 transmembrane-spanning receptor (7TMR). Activation of GPR54 by kisspeptin (Kp) stimulates PIP2 hydrolysis, Ca2+ mobilization and ERK1/2 MAPK phosphorylation. Kp and GPR54 are established regulators of the hypothalamic-pituitary-gonadal (HPG) axis and loss-of-function mutations in GPR54 are associated with an absence of puberty and hypogonadotropic hypogonadism, thus defining an important role of the Kp/GPR54 signaling system in reproductive function. Given the tremendous physiological and clinical importance of the Kp/GPR54 signaling system, we explored the contributions of the GPR54-coupled Gq/11 and β-arrestin pathways on the activation of a major downstream signaling molecule, ERK, using Gq/11 and β-arrestin knockout mouse embryonic fibroblasts. Our study revealed that GPR54 employs the Gq/11 and β-arrestin-2 pathways in a co-dependent and temporally overlapping manner to positively regulate ERK activity and pERK nuclear localization. We also show that while β-arrestin-2 potentiates GPR54 signaling to ERK, β-arrestin-1 inhibits it. Our data also revealed that diminished β-arrestin-1 and -2 expression in the GT1-7 GnRH hypothalamic neuronal cell line triggered distinct patterns of gene expression following Kp-10 treatment. Thus, β-arrestin-1 and -2 also regulate distinct downstream responses in gene expression. Finally, we showed that GPR54, when uncoupled from the Gq/11 pathway, as is the case for several naturally occurring GPR54 mutants associated with hypogonadotropic hypogonadism, continues to regulate gene expression in a G protein-independent manner. These new and exciting findings add significantly to our mechanistic understanding of how this important receptor signals intracellularly in response to kisspeptin stimulation.
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Affiliation(s)
- Jacob M. Szereszewski
- The Children's Health Research Institute, London, Ontario, Canada
- Lawson Health Research Institute, London, Ontario, Canada
- Department of Obstetrics and Gynaecology, The University of Western Ontario, London, Ontario, Canada
- Department of Physiology and Pharmacology, The University of Western Ontario, London, Ontario, Canada
| | - Macarena Pampillo
- The Children's Health Research Institute, London, Ontario, Canada
- Lawson Health Research Institute, London, Ontario, Canada
- Department of Obstetrics and Gynaecology, The University of Western Ontario, London, Ontario, Canada
| | - Maryse R. Ahow
- The Children's Health Research Institute, London, Ontario, Canada
- Lawson Health Research Institute, London, Ontario, Canada
- Department of Obstetrics and Gynaecology, The University of Western Ontario, London, Ontario, Canada
- Department of Physiology and Pharmacology, The University of Western Ontario, London, Ontario, Canada
| | - Stefan Offermanns
- Department of Pharmacology, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Moshmi Bhattacharya
- Department of Physiology and Pharmacology, The University of Western Ontario, London, Ontario, Canada
| | - Andy V. Babwah
- The Children's Health Research Institute, London, Ontario, Canada
- Lawson Health Research Institute, London, Ontario, Canada
- Department of Obstetrics and Gynaecology, The University of Western Ontario, London, Ontario, Canada
- Department of Physiology and Pharmacology, The University of Western Ontario, London, Ontario, Canada
- * E-mail:
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21
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Mangmool S, Shukla AK, Rockman HA. beta-Arrestin-dependent activation of Ca(2+)/calmodulin kinase II after beta(1)-adrenergic receptor stimulation. ACTA ACUST UNITED AC 2010; 189:573-87. [PMID: 20421423 PMCID: PMC2867304 DOI: 10.1083/jcb.200911047] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
β-Arrestin functions as a scaffold for CaMKII and the Rap guanine nucleotide exchange factor Epac to regulate signaling from β1-ARs. Ca2+/calmodulin kinase II (CaMKII) plays an important role in cardiac contractility and the development of heart failure. Although stimulation of β1–adrenergic receptors (ARs) leads to an increase in CaMKII activity, the molecular mechanism by which β1-ARs activate CaMKII is not completely understood. In this study, we show the requirement for the β1-AR regulatory protein β-arrestin as a scaffold for both CaMKII and Epac (exchange protein directly activated by cAMP). Stimulation of β1-ARs induces the formation of a β-arrestin–CaMKII–Epac1 complex, allowing its recruitment to the plasma membrane, whereby interaction with cAMP leads to CaMKII activation. β-Arrestin binding to the carboxyl-terminal tail of β1-ARs promotes a conformational change within β-arrestin that allows CaMKII and Epac to remain in a stable complex with the receptor. The essential role for β-arrestin and identification of the molecular mechanism by which only β1-ARs and not β2-ARs activate CaMKII significantly advances our understanding of this important cellular pathway.
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Affiliation(s)
- Supachoke Mangmool
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
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22
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Yang X, Zheng J, Xiong Y, Shen H, Sun L, Huang Y, Sun C, Li Y, He J. Beta-2 adrenergic receptor mediated ERK activation is regulated by interaction with MAGI-3. FEBS Lett 2010; 584:2207-12. [PMID: 20353789 DOI: 10.1016/j.febslet.2010.03.039] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Revised: 03/12/2010] [Accepted: 03/24/2010] [Indexed: 10/19/2022]
Abstract
The beta-2 adrenergic receptor (beta2AR) has a carboxyl terminus motif that can interact with PSD-95/discs-large/ZO1 homology (PDZ) domain-containing proteins. In this paper, we identified membrane-associated guanylate kinase inverted-3 (MAGI-3) as a novel binding partner of beta2AR. The carboxyl terminus of beta2AR binds with high affinity to the fifth PDZ domain of MAGI-3, with the last four amino acids (D-S-L-L) of the receptor being the key determinants of the interaction. In cells, the association of full-length beta2AR with MAGI-3 occurs constitutively and is enhanced by agonist stimulation of the receptor. Our data also demonstrated that beta2AR-stimulated extracellular signal-regulated kinase-1/2 (ERK1/2) activation was substantially retarded by MAGI-3 expression. These data suggest that MAGI-3 regulates beta2AR-mediated ERK activation through the physical interaction between beta2AR and MAGI-3.
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Affiliation(s)
- Xiaomei Yang
- Department of Biochemistry and Molecular Biology, Capital Medical University, Beijing, PR China
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23
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Zheng H, Loh HH, Law PY. Agonist-selective signaling of G protein-coupled receptor: mechanisms and implications. IUBMB Life 2010; 62:112-9. [PMID: 20058265 DOI: 10.1002/iub.293] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Agonist-selective signaling or ligand-biased signaling of G protein-coupled receptor (GPCR) has become the focus of an increasing number of laboratories. The principle of this concept is that agonist possesses different abilities to activate different signaling pathways. Current review summarizes the observations of agonist-selective signaling of various GPCRs, indicating the significance of agonist-selective signaling in biological processes. In addition, current review also provides an overview on how agonist-selective signaling is initiated. Especially, the relationship between GPCR-G protein interaction and GPCR-beta-arrestin interaction is discussed in depth.
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Affiliation(s)
- Hui Zheng
- Department of Pharmacology, University of Minnesota, Minneapolis, MN 55455-0217, USA.
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24
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Evans BA, Sato M, Sarwar M, Hutchinson DS, Summers RJ. Ligand-directed signalling at beta-adrenoceptors. Br J Pharmacol 2010; 159:1022-38. [PMID: 20132209 DOI: 10.1111/j.1476-5381.2009.00602.x] [Citation(s) in RCA: 130] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
beta-Adrenoceptors (ARs) classically mediate responses to the endogenous ligands adrenaline and noradrenaline by coupling to Gsalpha and stimulating cAMP production; however, drugs designed as beta-AR agonists or antagonists can activate alternative cell signalling pathways, with the potential to influence clinical efficacy. Furthermore, drugs acting at beta-ARs have differential capacity for pathway activation, described as stimulus trafficking, biased agonism, functional selectivity or ligand-directed signalling. These terms refer to responses where drug A has higher efficacy than drug B for one signalling pathway, but a lower efficacy than drug B for a second pathway. The accepted explanation for such responses is that drugs A and B have the capacity to induce or stabilize distinct active conformations of the receptor that in turn display altered coupling efficiency to different effectors. This is consistent with biophysical studies showing that drugs can indeed promote distinct conformational states. Agonists acting at beta-ARs display ligand-directed signalling, but many drugs acting as cAMP antagonists are also able to activate signalling pathways central to cell survival and proliferation or cell death. The observed complexity of drug activity at beta-ARs, prototypical G protein-coupled receptors, necessitates rethinking of the approaches used for screening and characterization of novel therapeutic agents. Most studies of ligand-directed signalling employ recombinant cell systems with high receptor abundance. While such systems are valid for examining upstream signalling events, such as receptor conformational changes and G protein activation, they are less robust when comparing downstream signalling outputs as these are likely to be affected by complex pathway interactions.
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Affiliation(s)
- Bronwyn A Evans
- Monash Institute of Pharmaceutical Sciences & Department of Pharmacology, Parkville, Vic, Australia
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25
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Tilley DG, Kim IM, Patel PA, Violin JD, Rockman HA. beta-Arrestin mediates beta1-adrenergic receptor-epidermal growth factor receptor interaction and downstream signaling. J Biol Chem 2009; 284:20375-86. [PMID: 19509284 DOI: 10.1074/jbc.m109.005793] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
beta1-Adrenergic receptor (beta1AR) stimulation confers cardioprotection via beta-arrestin-de pend ent transactivation of epidermal growth factor receptors (EGFRs), however, the precise mechanism for this salutary process is unknown. We tested the hypothesis that the beta1AR and EGFR form a complex that differentially directs intracellular signaling pathways. beta1AR stimulation and EGF ligand can each induce equivalent EGFR phosphorylation, internalization, and downstream activation of ERK1/2, but only EGF ligand causes translocation of activated ERK to the nucleus, whereas beta1AR-stimulated/EGFR-transactivated ERK is restricted to the cytoplasm. beta1AR and EGFR are shown to interact as a receptor complex both in cell culture and endogenously in human heart, an interaction that is selective and undergoes dynamic regulation by ligand stimulation. Although catecholamine stimulation mediates the retention of beta1AR-EGFR interaction throughout receptor internalization, direct EGF ligand stimulation initiates the internalization of EGFR alone. Continued interaction of beta1AR with EGFR following activation is dependent upon C-terminal tail GRK phosphorylation sites of the beta1AR and recruitment of beta-arrestin. These data reveal a new signaling paradigm in which beta-arrestin is required for the maintenance of a beta1AR-EGFR interaction that can direct cytosolic targeting of ERK in response to catecholamine stimulation.
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Affiliation(s)
- Douglas G Tilley
- Department of Medicine, Duke University, Medical Center, Durham, North Carolina 27710, USA
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26
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Li J, Ghio AJ, Cho SH, Brinckerhoff CE, Simon SA, Liedtke W. Diesel exhaust particles activate the matrix-metalloproteinase-1 gene in human bronchial epithelia in a beta-arrestin-dependent manner via activation of RAS. ENVIRONMENTAL HEALTH PERSPECTIVES 2009; 117:400-9. [PMID: 19337515 PMCID: PMC2661910 DOI: 10.1289/ehp.0800311] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2008] [Accepted: 10/29/2008] [Indexed: 05/17/2023]
Abstract
BACKGROUND Diesel exhaust particles (DEPs) are globally relevant air pollutants that exert a detrimental human health impact. However, mechanisms of damage by DEP exposure to human respiratory health and human susceptibility factors are only partially known. Matrix metalloproteinase-1 (MMP-1) has been implied as an (etio)pathogenic factor in human lung and airway diseases such as emphysema, chronic obstructive pulmonary disease, chronic asthma, tuberculosis, and bronchial carcinoma and has been reported to be regulated by DEPs. OBJECTIVE We elucidated the molecular mechanisms of DEPs' up-regulation of MMP-1. METHODS/RESULTS Using permanent and primary human bronchial epithelial (HBE) cells at air-liquid interface, we show that DEPs activate the human MMP-1 gene via RAS and subsequent activation of RAF-MEK-ERK1/2 mitogen-activated protein kinase signaling, which can be scaffolded by beta-arrestins. Short interfering RNA mediated beta-arrestin1/2 knockout eliminated formation, subsequent nuclear trafficking of phosphorylated ERK1/2, and resulting MMP-1 transcriptional activation. Transcriptional regulation of the human MMP-1 promoter was strongly influenced by the presence of the -1607GG polymorphism, present in 60-80% of humans, which led to striking up-regulation of MMP-1 transcriptional activation. CONCLUSION Our results confirm up-regulation of MMP-1 in response to DEPs in HBE and provide new mechanistic insight into how these epithelia, the first line of protection against environmental insults, up-regulate MMP-1 in response to DEP inhalation. These mechanisms include a role for the human -1607GG polymorphism as a susceptibility factor for an accentuated response, which critically depends on the ability of beta-arrestin1/2 to generate scaffolding and nuclear trafficking of phosphorylated ERK1/2.
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Affiliation(s)
- Jinju Li
- Department of Neurobiology, Duke University, Durham, North Carolina, USA
| | - Andrew J. Ghio
- U.S. Environmental Protection Agency, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Seung-Hyun Cho
- U.S. Environmental Protection Agency, Research Triangle Park, Research Triangle Park, North Carolina, USA
| | - Constance E. Brinckerhoff
- Departments of Medicine and Biochemistry, Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA
| | - Sidney A. Simon
- Department of Neurobiology, Duke University, Durham, North Carolina, USA
- Center for Neuroengineering and
| | - Wolfgang Liedtke
- Department of Neurobiology, Duke University, Durham, North Carolina, USA
- Division of Neurology, Department of Medicine, Duke University, Durham, North Carolina, USA
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The β1-adrenergic receptor mediates extracellular signal-regulated kinase activation via Gαs. Amino Acids 2008; 38:75-84. [DOI: 10.1007/s00726-008-0207-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Accepted: 11/03/2008] [Indexed: 01/14/2023]
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Nyan DC, Anbazhagan R, Hughes-Darden CA, Wachira SJM. Endosomal colocalization of melanocortin-3 receptor and beta-arrestins in CAD cells with altered modification of AKT/PKB. Neuropeptides 2008; 42:355-66. [PMID: 18291523 DOI: 10.1016/j.npep.2007.12.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2007] [Revised: 12/20/2007] [Accepted: 12/21/2007] [Indexed: 01/14/2023]
Abstract
The melanocortin 3-receptor is involved in regulating energy metabolism, body fluid composition and inflammatory responses. Melanocortin receptors function by activating membrane bound adenylate cyclase. However, the literature reports indicate that some G protein coupled receptors (GPCRs) can also activate mitogen activated protein kinase (MAPK) or phosphoinositide 3 kinase (PI3K) signaling pathways consequent to their endocytosis. These studies were undertaken to evaluate the role of these pathways in MC3R signaling in brain-stem neuronal cells. Recruitment of arrestins is implicated in the activation of secondary pathways by GPCRs and our data shows the colocalization of either arrestin B1 or B2 with MC3R in endosomes. An alteration in PKB phosphorylation pattern was observed in MC3R expressing cells independent of agonist stimulation. MC3R transfectants exhibited increased proliferation rates and inhibition of PKB pathway with triciribine abrogated cell proliferation in both vector control and MC3R transfectants. PKB is constitutively active in proliferating CAD cells but could be further activated by culturing the cells in differentiation medium. These studies suggest that the AKT/PKB pathway plays an important role in the proliferation of CAD cells and suggest a link between MC3R and cell growth pathways that may involve the alteration of AKT/PKB signaling pathway.
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Affiliation(s)
- D C Nyan
- Department of Biology, Morgan State University, Baltimore, MD 21251, USA
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29
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Beta-arrestins and heterotrimeric G-proteins: collaborators and competitors in signal transduction. Br J Pharmacol 2007; 153 Suppl 1:S298-309. [PMID: 18037927 DOI: 10.1038/sj.bjp.0707508] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
G-protein-coupled receptors (GPCRs), also known as seven transmembrane receptors (7-TMRs), are the largest protein receptor superfamily in the body. These receptors and their ligands direct a diverse array of physiological responses, and hence have broad relevance to numerous diseases. As a result, they have generated considerable interest in the pharmaceutical industry as drug targets. Recently, GPCRs have been demonstrated to elicit signals through interaction with the scaffolding proteins, beta-arrestins-1 and 2, independent of heterotrimeric G-protein coupling. This review discusses several known G-protein-independent, beta-arrestin-dependent pathways and their potential physiological and pharmacological significance. The emergence of G-protein-independent signalling changes the way in which GPCR signalling is evaluated, from a cell biological to a pharmaceutical perspective and raises the possibility for the development of pathway specific therapeutics.
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Zheng H, Loh HH, Law PY. Beta-arrestin-dependent mu-opioid receptor-activated extracellular signal-regulated kinases (ERKs) Translocate to Nucleus in Contrast to G protein-dependent ERK activation. Mol Pharmacol 2007; 73:178-90. [PMID: 17947509 DOI: 10.1124/mol.107.039842] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The cellular location of extracellular signal-regulated kinases (ERKs) activated by a G protein-coupled receptor was shown to be dependent on the pathway that mediated their activation. In general, fast activation of ERKs (2 min) mediated by G proteins resulted in the nuclear translocation of phosphorylated ERKs, whereas a slower activation of ERKs (10 min) mediated by beta-arrestins resulted in the cytosolic retention of the phosphorylated ERKs. However, we observed distinct differences from this established ERKs cellular itinerary with the mu-opioid receptor-activated ERKs. Agonists such as morphine and methadone activated ERKs via the protein kinase C-dependent pathway but not the beta-arrestin-dependent pathway. The activated ERKs did not translocate into the nucleus, but phosphorylated 90-kDa ribosomal S6 kinase and induced the activity of transcription factor cAMP response element-binding protein. In contrast, agonists such as etorphine and fentanyl activated ERKs in a beta-arrestin-dependent manner. The phosphorylated ERKs translocated into the nucleus, resulting in increases in Elk-1 activity and GRK2 and beta-arrestin2 transcriptions. Thus, the cellular location of phosphorylated ERKs and subsequent activities on gene transcriptions are dictated by the agonist used to activate the receptor and the subsequent signaling pathway involved.
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Affiliation(s)
- Hui Zheng
- Department of Pharmacology, Medical School, University of Minnesota. 6-120 Jackson Hall, 321 Church Street S.E., Minneapolis, MN 55455-0217, USA.
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31
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Pilecka I, Banach-Orlowska M, Miaczynska M. Nuclear functions of endocytic proteins. Eur J Cell Biol 2007; 86:533-47. [PMID: 17583371 DOI: 10.1016/j.ejcb.2007.04.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2007] [Revised: 04/19/2007] [Accepted: 04/19/2007] [Indexed: 01/14/2023] Open
Abstract
An increasing number of proteins appear to perform multiple, sometimes unrelated functions in the cell. Such moonlighting properties have been recently demonstrated for proteins involved in clathrin-mediated endocytosis. Some clathrin adaptors and endosomal proteins can undergo nucleocytoplasmic shuttling, which is often based on intrinsic sequence motifs and requires active transport mechanisms. Endocytic proteins can associate with nuclear molecules, changing their localization and/or activity and may modulate the levels and specificity of gene transcription. It is not clear how the nuclear and cytoplasmic pools of endocytic proteins are interconnected, or whether these molecules act as nuclear second messengers upon extracellular stimuli, but alike in endocytosis, they seem to form multi-component scaffolding platforms in the nucleus. Added to their endocytic functions, the nuclear roles of Eps15, Epsin1, CALM, HIP1, Dab1/2, beta-arrestins, APPL1/2 and the components of ESCRTs clearly increase the complexity of signaling networks affecting cellular growth, proliferation and homeostasis.
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Affiliation(s)
- Iwona Pilecka
- International Institute of Molecular and Cell Biology, Laboratory of Cell Biology, 4 Ks. Trojdena Street, 02-109 Warsaw, Poland
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32
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Aplin M, Christensen GL, Schneider M, Heydorn A, Gammeltoft S, Kjølbye AL, Sheikh SP, Hansen JL. The angiotensin type 1 receptor activates extracellular signal-regulated kinases 1 and 2 by G protein-dependent and -independent pathways in cardiac myocytes and langendorff-perfused hearts. Basic Clin Pharmacol Toxicol 2007; 100:289-95. [PMID: 17448113 DOI: 10.1111/j.1742-7843.2007.00063.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The angiotensin II (AngII) type 1 receptor (AT(1)R) has been shown to activate extracellular signal-regulated kinases 1 and 2 (ERK1/2) through G proteins or G protein-independently through beta-arrestin2 in cellular expression systems. As activation mechanisms may greatly influence the biological effects of ERK1/2 activity, differential activation of the AT(1)R in its native cellular context could have important biological and pharmacological implications. To examine if AT(1)R activates ERK1/2 by G protein-independent mechanisms in the heart, we used the [Sar(1), Ile(4), Ile(8)]-AngII ([SII] AngII) analogue in native preparations of cardiac myocytes and beating hearts. We found that [SII] AngII does not activate G(q)-coupling, yet stimulates the beta-arrestin2-dependent ERK1/2. The G(q)-activated pool of ERK1/2 rapidly translocates to the nucleus, while the beta-arrestin2-scaffolded pool remains in the cytosol. Similar biased agonism was achieved in Langendorff-perfused hearts, where both agonists elicit ERK1/2 phosphorylation, but [SII] AngII induces neither inotropic nor chronotropic effects.
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Affiliation(s)
- Mark Aplin
- Laboratory for Molecular Cardiology, Danish National Research Foundation Centre for Cardiac Arrhythmia, and the Heart Centre, Copenhagen University Hospital, Copenhagen, Denmark
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Goetzl EJ. Diverse pathways for nuclear signaling by G protein‐coupled receptors and their ligands. FASEB J 2006; 21:638-42. [PMID: 17194692 DOI: 10.1096/fj.06-6624hyp] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Recent realization that plasma membrane G protein-coupled receptors (GPCRs) may translocate and establish ligand-responsive signaling complexes in other cellular structures has motivated studies of site-specific differences in transductional pathways. GPCRs and their ligands may signal transcription and other nuclear events by two basic mechanisms. The first consists of GPCR-complex activation of messengers that enter the nucleus and there initiate cell-modifying processes without the GPCR leaving the plasma membrane. The second encompasses entry into the nuclear membranes or matrix of either GPCR ligands, which bind to non-GPCR nuclear signaling proteins, proteolytic fragments of GPCRs capable of ligand-independent signaling, or intact GPCRs with transduction-competent factors that directly initiate or regulate transcriptional events. With the second mechanism, often concurrent down-regulation of plasma membrane GPCRs terminates signaling from the cell-surface and moves it into the nuclear domain. Site-dependent differences in signals from the same GPCR provide potentials for unique cellular abnormalities attributable to defective intracellular movement and distribution of a GPCR, site-specific alterations in ligand concentration, and limited intracellular bioavailability of pharmacological agents that can interact specifically with both nuclear and plasma membrane forms of a GPCR.
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Affiliation(s)
- Edward J Goetzl
- Department of Medicine, University of California, San Francisco, California, USA.
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Neuhaus EM, Mashukova A, Barbour J, Wolters D, Hatt H. Novel function of β-arrestin2 in the nucleus of mature spermatozoa. J Cell Sci 2006; 119:3047-56. [PMID: 16820410 DOI: 10.1242/jcs.03046] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
A growing number of proteins originally found in endocytic structures of the plasma membrane appear to be able to traffic into the nucleus, but the cellular function of this translocation remains unclear. We have found that β-arrestin2, which typically shows a cytoplasmic localization owing to constitutive nuclear export, appears in the nucleus after stimulation of the G-protein-coupled odorant receptor hOR17-4. In the nucleus, β-arrestin2 was involved in transcriptional regulation as shown by a Gal4-based transactivation assay. Moreover, we discovered that β-arrestin2 and hOR17-4, a receptor known to have a role in sperm-egg communication, colocalize in the midpiece of mature human spermatozoa. Stimulation of hOR17-4 in spermatozoa induced PKA-dependent translocation of β-arrestin2 to the nucleus and nuclear accumulation of phosphorylated MAPKs. Analysis of the interaction partners of β-arrestin2 indicates that odorant receptor signaling in spermatozoa may be important for the regulation of gene expression during the early processes of fertilization.
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Affiliation(s)
- Eva M Neuhaus
- Department of Cell Physiology, Ruhr-Universitaet Bochum, Universitaetsstr. 150, 44780 Bochum, Germany.
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