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Qi M, Chen TT, Li L, Gao PP, Li N, Zhang SH, Wei W, Sun WY. Insight into the regulatory mechanism of β-arrestin2 and its emerging role in diseases. Br J Pharmacol 2024; 181:3019-3038. [PMID: 38961617 DOI: 10.1111/bph.16488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 05/11/2024] [Accepted: 05/27/2024] [Indexed: 07/05/2024] Open
Abstract
β-arrestin2, a member of the arrestin family, mediates the desensitization and internalization of most G protein-coupled receptors (GPCRs) and functions as a scaffold protein in signalling pathways. Previous studies have demonstrated that β-arrestin2 expression is dysregulated in malignant tumours, fibrotic diseases, cardiovascular diseases and metabolic diseases, suggesting its pathological roles. Transcription and post-transcriptional modifications can affect the expression of β-arrestin2. Furthermore, post-translational modifications, such as phosphorylation, ubiquitination, SUMOylation and S-nitrosylation affect the cellular localization of β-arrestin2 and its interaction with downstream signalling molecules, which further regulate the activity of β-arrestin2. This review summarizes the structure and function of β-arrestin2 and reveals the mechanisms involved in the regulation of β-arrestin2 at multiple levels. Additionally, recent studies on the role of β-arrestin2 in some major diseases and its therapeutic prospects have been discussed to provide a reference for the development of drugs targeting β-arrestin2.
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Affiliation(s)
- Meng Qi
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Center of Anhui-inflammatory and Immune Medicine, Hefei, China
| | - Ting-Ting Chen
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Center of Anhui-inflammatory and Immune Medicine, Hefei, China
| | - Ling Li
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Center of Anhui-inflammatory and Immune Medicine, Hefei, China
| | - Ping-Ping Gao
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Center of Anhui-inflammatory and Immune Medicine, Hefei, China
| | - Nan Li
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Center of Anhui-inflammatory and Immune Medicine, Hefei, China
| | - Shi-Hao Zhang
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Center of Anhui-inflammatory and Immune Medicine, Hefei, China
| | - Wei Wei
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Center of Anhui-inflammatory and Immune Medicine, Hefei, China
| | - Wu-Yi Sun
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Center of Anhui-inflammatory and Immune Medicine, Hefei, China
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Kundu D, Acharya S, Wang S, Kim KM. Unveiling the intracellular dynamics of α4β2 nAChR-mediated ERK activation through the interplay of arrestin, Gβγ, and PKCβII. Life Sci 2024:122994. [PMID: 39163903 DOI: 10.1016/j.lfs.2024.122994] [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: 05/26/2024] [Revised: 07/28/2024] [Accepted: 08/14/2024] [Indexed: 08/22/2024]
Abstract
AIMS In contrast to G protein-coupled receptors or receptor tyrosine kinases, the mechanism underlying ERK activation through nicotine acetylcholine receptors (nAChRs), members of the ligand-gated ion channel family, remains poorly elucidated. This study aimed to delineate the signaling pathway responsible for ERK activation by the α4β2 nAChR subtype, which is implicated in nicotine addiction and various mental disorders. MATERIALS AND METHODS Loss-of-function strategies and mutants of arrestin2/PKCβII with distinct functional characteristics were employed to identify the cellular components and processes involved in ERK activation. KEY FINDINGS ERK activation via α4β2 nAChR was observed within the nucleus and necessitated the nuclear translocation of arrestin2 and PKCβII, which exhibited mutual augmentation. Activation of PKCβII by α4β2 nAChR stimulation facilitated the nuclear translocation of arrestin2 by enhancing its interaction with importin β1. Apart from scaffolding ERK activation in the nucleus, arrestin2, in cooperation with GRK2, facilitated the activation of the Src/Syk/PKCβII signaling cascade, leading to the nuclear entry of PKCβII in a Gβγ-dependent manner. Upon nuclear localization, PKCβII underwent ubiquitination by Mdm2 and interacted with MEK1, resulting in ERK activation. In summary, α4β2 nAChR-mediated ERK activation in the nucleus involves the nuclear translocation of arrestin2 and PKCβII, which is reciprocally facilitated via positive feedback augmentation. SIGNIFICANCE As α4β2 nAChRs play a pivotal role in various cellular processes including drug addiction and mental disorders, our findings will offer insights into understanding the pathogenesis of α4β2 nAChR-related disorders and may facilitate the development of targeted therapeutic interventions.
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Affiliation(s)
- Dooti Kundu
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Srijan Acharya
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Shujie Wang
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Kyeong-Man Kim
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwangju 61186, Republic of Korea.
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Chen Q, Huang Z, Chen J, Tian X, Zhang R, Liang Q, Liu Z, Cheng Y. Notoginsenoside R1 attenuates ischemic heart failure by modulating MDM2/β arrestin2-mediated β2-adrenergic receptor ubiquitination. Biomed Pharmacother 2024; 177:117004. [PMID: 38955084 DOI: 10.1016/j.biopha.2024.117004] [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: 03/13/2024] [Revised: 06/10/2024] [Accepted: 06/17/2024] [Indexed: 07/04/2024] Open
Abstract
β2 adrenergic receptor (β2AR) is a G-protein-coupled receptor involved in cardiac protection. In chronic heart failure (CHF), persistent sympathetic nervous system activation occurs, resulting in prolonged β2AR activation and subsequent receptor desensitization and downregulation. Notoginsenoside R1 (NGR1) has the functions of enhancing myocardial energy metabolism and mitigating myocardial fibrosis. The mechanisms of NGR1 against ischemic heart failure are unclear. A left anterior descending (LAD) artery ligation procedure was performed on C57BL/6 J mice for four weeks. From the 4th week onwards, they were treated with various doses (3, 10, 30 mg/kg/day) of NGR1. Subsequently, the impacts of NGR1 on ischemic heart failure were evaluated by assessing cardiac function, morphological changes in cardiac tissue, and the expression of atrial natriuretic peptide (ANP) and beta-myosin heavy chain (β-MHC). H9c2 cells were protected by NGR1 when exposed to OGD/R conditions. H9c2 cells were likewise protected from OGD/R damage by NGR1. Furthermore, NGR1 increased β2AR levels and decreased β2AR ubiquitination. Mechanistic studies revealed that NGR1 enhanced MDM2 protein stability and increased the expression of MDM2 and β-arrestin2 while inhibiting their interaction. Additionally, under conditions produced by OGD/R, the protective benefits of NGR1 on H9c2 cells were attenuated upon administration of the MDM2 inhibitor SP141. According to these findings, NGR1 impedes the interplay between β-arrestin2 and MDM2, thereby preventing the ubiquitination and degradation of β2AR to improve CHF.
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Affiliation(s)
- Qi Chen
- Guangdong Provincial Key Laboratory of Translational Cancer Research of Chinese Medicines, Joint International Research Laboratory of Translational Cancer Research of Chinese Medicines, International Institute for Translational Chinese Medicine, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, China
| | - Ziwei Huang
- Guangdong Provincial Key Laboratory of Translational Cancer Research of Chinese Medicines, Joint International Research Laboratory of Translational Cancer Research of Chinese Medicines, International Institute for Translational Chinese Medicine, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, China
| | - Jing Chen
- Department of Cardiovascular Disease, The First Afliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, China
| | - Xiaoyu Tian
- Guangdong Provincial Key Laboratory of Translational Cancer Research of Chinese Medicines, Joint International Research Laboratory of Translational Cancer Research of Chinese Medicines, International Institute for Translational Chinese Medicine, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, China
| | - Rong Zhang
- Guangdong Provincial Key Laboratory of Translational Cancer Research of Chinese Medicines, Joint International Research Laboratory of Translational Cancer Research of Chinese Medicines, International Institute for Translational Chinese Medicine, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, China
| | - Qi Liang
- Shenzhen Bao'an Traditional Chinese Medicine Hospital Group, Shenzhen 518000, China.
| | - Zhongqiu Liu
- Guangdong Provincial Key Laboratory of Translational Cancer Research of Chinese Medicines, Joint International Research Laboratory of Translational Cancer Research of Chinese Medicines, International Institute for Translational Chinese Medicine, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, China.
| | - Yuanyuan Cheng
- Guangdong Provincial Key Laboratory of Translational Cancer Research of Chinese Medicines, Joint International Research Laboratory of Translational Cancer Research of Chinese Medicines, International Institute for Translational Chinese Medicine, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, China.
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Zeng J, Ye C, Zhang C, Su H. Membranous translocation of murine double minute 2 promotes the increased renal tubular immunogenicity in ischemia-reperfusion-induced acute kidney injury. Am J Physiol Renal Physiol 2024; 327:F290-F303. [PMID: 38867673 DOI: 10.1152/ajprenal.00200.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 06/04/2024] [Accepted: 06/05/2024] [Indexed: 06/14/2024] Open
Abstract
Kidneys from donors with prolonged warm and cold ischemia are prone to posttransplant T cell-mediated rejection (TCMR) due to ischemia-reperfusion injury (IRI). However, the precise mechanisms still remain obscure. Renal tubular epithelial cells (TECs) are the main target during IRI. Meanwhile, we have previously reported that murine double minute 2 (MDM2) actively participates in TEC homeostasis during IRI. In this study, we established a murine model of renal IRI and a cell model of hypoxia-reoxygenation by culturing immortalized rat renal proximal tubule cells (NRK-52E) in a hypoxic environment for different time points followed by 24 h of reoxygenation and incubating NRK-52E cells in a chemical anoxia-recovery environment. We found that during renal IRI MDM2 expression increased on the membrane of TECs and aggregated mainly on the basolateral side. This process was accompanied by a reduction of a transmembrane protein, programmed death ligand 1 (PD-L1), a coinhibitory second signal for T cells in TECs. Using mutant plasmids of MDM2 to anchor MDM2 on the cell membrane or nuclei, we found that the upregulation of membrane MDM2 could promote the ubiquitination of PD-L1 and lead to its ubiquitination-proteasome degradation. Finally, we set up a coculture system of TECs and CD4+ T cells in vitro; our results revealed that the immunogenicity of TECs was enhanced during IRI. In conclusion, our findings suggest that the increased immunogenicity of TECs during IRI may be related to ubiquitinated degradation of PD-L1 by increased MDM2 on the cell membrane, which consequently results in T-cell activation and TCMR.NEW & NOTEWORTHY Ischemic acute kidney injury (AKI) donors can effectively shorten the waiting time for kidney transplantation but increase immune rejection, especially T cell-mediated rejection (TCMR), the mechanism of which remains to be elucidated. Our study demonstrates that during ischemia-reperfusion injury (IRI), the translocation of tubular murine double minute 2 leads to basolateral programmed death ligand 1 degradation, which ultimately results in the occurrence of TCMR, which may provide a new therapeutic strategy for preventing AKI donor-associated TCMR.
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Affiliation(s)
- Jieyu Zeng
- Department of Nephrology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and Technology Wuhan Hubei China
| | - Chen Ye
- Department of Nephrology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and Technology Wuhan Hubei China
| | - Chun Zhang
- Department of Nephrology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and Technology Wuhan Hubei China
| | - Hua Su
- Department of Nephrology, Union Hospital, Tongji Medical CollegeHuazhong University of Science and Technology Wuhan Hubei China
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Wu C, Hu L, Liu B, Zeng X, Ma H, Cao Y, Li H, Zhang X. TRAF6-mediated ubiquitination of AKT in the nucleus is a critical event underlying the desensitization of G protein-coupled receptors. Cell Commun Signal 2024; 22:213. [PMID: 38566235 PMCID: PMC10986131 DOI: 10.1186/s12964-024-01592-z] [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: 01/21/2024] [Accepted: 03/23/2024] [Indexed: 04/04/2024] Open
Abstract
BACKGROUND Desensitization of G protein-coupled receptors (GPCRs) refers to the attenuation of receptor responsiveness by prolonged or intermittent exposure to agonists. The binding of β-arrestin to the cytoplasmic cavity of the phosphorylated receptor, which competes with the G protein, has been widely accepted as an extensive model for explaining GPCRs desensitization. However, studies on various GPCRs, including dopamine D2-like receptors (D2R, D3R, D4R), have suggested the existence of other desensitization mechanisms. The present study employed D2R/D3R variants with different desensitization properties and utilized loss-of-function approaches to uncover the mechanisms underlying GPCRs homologous desensitization, focusing on the signaling cascade that regulates the ubiquitination of AKT. RESULTS AKT undergoes K8/14 ubiquitination by TRAF6, which occurs in the nucleus and promotes its membrane recruitment, phosphorylation and activation under receptor desensitization conditions. The nuclear entry of TRAF6 relies on the presence of the importin complex. Src regulates the nuclear entry of TRAF6 by mediating the interaction between TRAF6 and importin β1. Ubiquitinated AKT translocates to the plasma membrane where it associates with Mdm2 to phosphorylate it at the S166 and S186 residues. Thereafter, phosphorylated Mdm2 is recruited to the nucleus, resulting in the deubiquitination of β-Arr2. The deubiquitinated β-Arr2 then forms a complex with Gβγ, which serves as a biomarker for GPCRs desensitization. Like in D3R, ubiquitination of AKT is also involved in the desensitization of β2 adrenoceptors. CONCLUSION Our study proposed that the property of a receptor that causes a change in the subcellular localization of TRAF6 from the cytoplasm to the nucleus to mediate AKT ubiquitination could initiate the desensitization of GPCRs.
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Affiliation(s)
- Chengyan Wu
- School of Pharmaceutical Sciences, Guizhou University, Guiyang, 550025, China
| | - Li Hu
- School of Pharmaceutical Sciences, Guizhou University, Guiyang, 550025, China
| | - Bing Liu
- School of Pharmaceutical Sciences, Guizhou University, Guiyang, 550025, China
| | - Xingyue Zeng
- School of Pharmaceutical Sciences, Guizhou University, Guiyang, 550025, China
| | - Haixiang Ma
- School of Pharmaceutical Sciences, Guizhou University, Guiyang, 550025, China
| | - Yongkai Cao
- Institute of Translational Medicine, The First Affiliated Hospital of Shenzhen University, Shenzhen, 518035, China
| | - Huijun Li
- Department of Pharmaceuticals, People's Hospital of Zunyi City Bo Zhou District, Zunyi, 563000, China
| | - Xiaohan Zhang
- School of Pharmaceutical Sciences, Guizhou University, Guiyang, 550025, China.
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Hai G, Bai J, Liu Y, Li J, Liu A, Wang J, Liu Q, Liu W, Wan P, Fu X. Superior performance of biocomposite nanoparticles PLGA-RES in protecting oocytes against vitrification stimuli. Front Bioeng Biotechnol 2024; 12:1376205. [PMID: 38529403 PMCID: PMC10961424 DOI: 10.3389/fbioe.2024.1376205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Accepted: 02/21/2024] [Indexed: 03/27/2024] Open
Abstract
Irreversible cryogenic damage caused by oocyte vitrification limits its widespread use in female fertility preservation. In recent years, nanoparticles (NPs) have gained great attention as potential alternatives in protecting oocytes against cryoinjuries. In this paper, a novel composite nanoparticle, poly (lactic-co-glycolic acid)-resveratrol (PLGA-RES) was designed to improve the biocompatibility and sustained release properties by encapsulating natural antioxidant RES into PLGA NPs. Firstly, biotoxicity and oxidation resistance of PLGA-RES were determined, and the results showed that PLGA-RES had nontoxic effect on oocyte survival during in vitro maturation (IVM) (97.08% ± 0.24% vs. 98.89% ± 1.11%, p > 0.05). Notably, PLGA-RES even increased maturation (65.10% ± 4.11% vs. 52.85% ± 2.87%, p < 0.05) and blastocyst rate (56.13% ± 1.36% vs. 40.91% ± 5.85%, p < 0.05). Moreover, the reduced reactive oxygen species (ROS) level (13.49 ± 2.30 vs. 34.07 ± 3.30, p < 0.01), increased glutathione (GSH) (44.13 ± 1.57 vs. 37.62 ± 1.79, p < 0.01) and elevated mitochondrial membrane potential (MMP) levels (43.10 ± 1.81 vs. 28.52 ± 1.25, p < 0.01) were observed in oocytes treated with PLGA-RES when compared with that of the control group. Subsequently, the role of PLGA-RES played in oocytes during vitrification was systematically evaluated. The results showed that the addition of PLGA-RES during vitrification and thawing significantly improved the survival rate (80.42% ± 1.97% vs. 75.37% ± 1.3%, p < 0.05). Meanwhile, increased GSH (15.09 ± 0.86 vs. 14.51 ± 0.78, p < 0.01) and mitochondrial membrane potential (22.56 ± 3.15 vs. 6.79 ± 0.60, p < 0.01), decreased reactive oxygen species levels (52.11 ± 2.95 vs. 75.41 ± 7.23, p < 0.05) and reduced mitochondrial abnormality distribution rate (25.00% ± 0.29% vs. 33.33% ± 1.15%, p < 0.01) were assessed in vitrified MII oocytes treated with PLGA-RES. Furthermore, transcriptomic analyses demonstrated that PLGA-RES participated in endocytosis and PI3K/AKT/mTOR pathway regulation, which was verified by the rescued expression of ARRB2 and ULK3 protein after PLGA-RES treatment. In conclusion, PLGA-RES exhibited potent antioxidant activity, and could be used as an efficacious strategy to improve the quality of vitrified oocytes.
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Affiliation(s)
- Guiping Hai
- College of Animal Science, Xinjiang Agricultural University, Ürümqi, China
| | - Jiachen Bai
- State Key Laboratory of Sheep Genetic Improvement and Healthy Breeding, Institute of Animal Husbandry and Veterinary Sciences, Xinjiang Academy of Agricultural and Reclamation Sciences, Shihezi, China
| | - Yucheng Liu
- State Key Laboratory of Sheep Genetic Improvement and Healthy Breeding, Institute of Animal Husbandry and Veterinary Sciences, Xinjiang Academy of Agricultural and Reclamation Sciences, Shihezi, China
| | - Jun Li
- Department of Reproductive Medicine, Reproductive Medical Center, The First Hospital of Hebei Medical University, Shijiazhuang, China
| | - Aiju Liu
- National Engineering Laboratory for Animal Breeding, Key Laboratory of Animal Genetics, Breeding and Reproduction of the MARA, Beijing Key Laboratory for Animal Genetic Improvement, State Key Laboratory of Animal Biotech Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Jingjing Wang
- State Key Laboratory of Sheep Genetic Improvement and Healthy Breeding, Institute of Animal Husbandry and Veterinary Sciences, Xinjiang Academy of Agricultural and Reclamation Sciences, Shihezi, China
| | - Qian Liu
- National Engineering Laboratory for Animal Breeding, Key Laboratory of Animal Genetics, Breeding and Reproduction of the MARA, Beijing Key Laboratory for Animal Genetic Improvement, State Key Laboratory of Animal Biotech Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Weijun Liu
- College of Animal Science, Xinjiang Agricultural University, Ürümqi, China
| | - Pengcheng Wan
- State Key Laboratory of Sheep Genetic Improvement and Healthy Breeding, Institute of Animal Husbandry and Veterinary Sciences, Xinjiang Academy of Agricultural and Reclamation Sciences, Shihezi, China
| | - Xiangwei Fu
- National Engineering Laboratory for Animal Breeding, Key Laboratory of Animal Genetics, Breeding and Reproduction of the MARA, Beijing Key Laboratory for Animal Genetic Improvement, State Key Laboratory of Animal Biotech Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China
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Wang S, Peng L, Kim KM. Biased Dopamine D 2 Receptors Exhibit Distinct Intracellular Trafficking Properties and ERK Activation in Different Subcellular Domains. Biomol Ther (Seoul) 2024; 32:56-64. [PMID: 37465849 PMCID: PMC10762269 DOI: 10.4062/biomolther.2023.033] [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: 02/19/2023] [Revised: 06/18/2023] [Accepted: 06/27/2023] [Indexed: 07/20/2023] Open
Abstract
Biased signaling or functional selectivity refers to the ability of an agonist or receptor to selectively activate a subset of transducers such as G protein and arrestin in the case of G protein-coupled receptors (GPCRs). Although signaling through arrestin has been reported from various GPCRs, only a few studies have examined side-by-side how it differs from signaling via G protein. In this study, two signaling pathways were compared using dopamine D2 receptor (D2R) mutants engineered via the evolutionary tracer method to selectively transduce signals through G protein or arrestin (D2G and D2Arr, respectively). D2G mediated the inhibition of cAMP production and ERK activation in the cytoplasm. D2Arr, in contrast, mediated receptor endocytosis accompanied by arrestin ubiquitination and ERK activation in the nucleus as well as in the cytoplasm. D2Arr-mediated ERK activation occurred in a manner dependent on arrestin3 but not arrestin2, accompanied by the nuclear translocation of arrestin3 via importin1. D2R-mediated ERK activation, which occurred in both the cytosol and nucleus, was limited to the cytosol when cellular arrestin3 was depleted. This finding supports the results obtained with D2Arr and D2G. Taken together, these observations indicate that biased signal transduction pathways activate distinct downstream mechanisms and that the subcellular regions in which they occur could be different when the same effectors are involved. These findings broaden our understanding on the relation between biased receptors and the corresponding downstream signaling, which is critical for elucidating the functional roles of biased pathways.
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Affiliation(s)
- Shujie Wang
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Lulu Peng
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Kyeong-Man Kim
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwangju 61186, Republic of Korea
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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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9
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Liu H, Ma H, Zeng X, Wu C, Acharya S, Sudan SK, Zhang X. Ubiquitination of GRK2 Is Required for the β-Arrestin-Biased Signaling Pathway of Dopamine D2 Receptors to Activate ERK Kinases. Int J Mol Sci 2023; 24:10031. [PMID: 37373182 DOI: 10.3390/ijms241210031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Revised: 06/06/2023] [Accepted: 06/07/2023] [Indexed: 06/29/2023] Open
Abstract
A class-A GPCR dopamine D2 receptor (D2R) plays a critical role in the proper functioning of neuronal circuits through the downstream activation of both G-protein- and β-arrestin-dependent signaling pathways. Understanding the signaling pathways downstream of D2R is critical for developing effective therapies with which to treat dopamine (DA)-related disorders such as Parkinson's disease and schizophrenia. Extensive studies have focused on the regulation of D2R-mediated extracellular-signal-regulated kinase (ERK) 1/2 signaling; however, the manner in which ERKs are activated upon the stimulation of a specific signaling pathway of D2R remains unclear. The present study conducted a variety of experimental techniques, including loss-of-function experiments, site-directed mutagenesis, and the determination of protein interactions, in order to investigate the mechanisms underlying β-arrestin-biased signaling-pathway-mediated ERK activation. We found that the stimulation of the D2R β-arrestin signaling pathway caused Mdm2, an E3 ubiquitin ligase, to move from the nucleus to the cytoplasm and interact with tyrosine phosphorylated G-protein-coupled receptor kinase 2 (GRK2), which was facilitated by Src, a non-receptor tyrosine kinase. This interaction led to the ubiquitination of GRK2, which then moved to the plasma membrane and interacted with activated D2R, followed by the phosphorylation of D2R as well as the mediation of ERK activation. In conclusion, Mdm2-mediated GRK2 ubiquitination, which is selectively triggered by the stimulation of the D2R β-arrestin signaling pathway, is necessary for GRK2 membrane translocation and its interaction with D2R, which in turn mediates downstream ERK signaling. This study is primarily novel and provides essential information with which to better understand the detailed mechanisms of D2R-dependent signaling.
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Affiliation(s)
- Haiping Liu
- School of Pharmaceutical Sciences, Guizhou University, Guiyang 550025, China
| | - Haixiang Ma
- School of Pharmaceutical Sciences, Guizhou University, Guiyang 550025, China
| | - Xingyue Zeng
- School of Pharmaceutical Sciences, Guizhou University, Guiyang 550025, China
| | - Chengyan Wu
- School of Pharmaceutical Sciences, Guizhou University, Guiyang 550025, China
| | - Srijan Acharya
- Mitchell Cancer Institute, School of Medicine, University of South Alabama, Mobile, AL 36604, USA
| | - Sarabjeet Kour Sudan
- Mitchell Cancer Institute, School of Medicine, University of South Alabama, Mobile, AL 36604, USA
| | - Xiaohan Zhang
- School of Pharmaceutical Sciences, Guizhou University, Guiyang 550025, China
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Tian X, Huang Z, Wang Y, Qi X, Wang D, Liu Z, Cheng Y. Xinbao Pill attenuated chronic heart failure by suppressing the ubiquitination of β-adrenergic receptors. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2023; 115:154830. [PMID: 37149964 DOI: 10.1016/j.phymed.2023.154830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 04/05/2023] [Accepted: 04/16/2023] [Indexed: 05/09/2023]
Abstract
BACKGROUD Xinbao Pill (XBP) is extensively used in the adjuvant treatment of chronic heart failure in China. However, the pharmacological effect and underlying mechanism on CHF remains unclear. PURPOSE Our research was performed to investigate the cardioprotective effect of XBP against CHF and uncover the potential mechanism. METHODS Male Sprague-Dawley (SD) rats were subjected to the left anterior descending (LAD) artery ligation for 8 weeks and were treated with different doses of XBP (from the 4th week to the end). Cardiac function and morphology assessment were performed by using M-mode echocardiography, H&E and Masson staining. Western blotting analysis, co-immunoprecipitation (IP) assays, siRNA transfection were used to evaluate the mechanism of XBP. RESULTS XBP improved cardiac function and alleviated cardiac fibrosis in LAD-induced chronic heart failure rats. Meanwhile, XBP protected cardiomyocytes against oxygen-glucose deprivation (OGD) injury in AC16 cells and H9c2 cells. Additionally, XBP could increase the expression of β1-AR and β2-AR and inhibit their ubiquitanation. Further mechanism study showed that XBP upregulated USP18 expression, while silence of USP18 attenuated the cardioprotective effect of XBP and the increase of β1-AR by XBP. Moreover, XBP increased MDM2 and β-arrestin2, and disrupted the interaction between Nedd4 and β2-AR. After using the inhibitor of MDM2, SP141, the cardioprotective effect of XBP and the inhibitory effect on the ubiquitanation of β2-AR were also blocked. CONCLUSION Our study firstly revealed that XBP improved cardiac function against CHF through suppressing USP18 and MDM2/β-arrestin2/Nedd4-mediated the ubiquitination of β1-AR and β2-AR.
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Affiliation(s)
- Xiaoyu Tian
- Joint Laboratory for Translational Cancer Research of Chinese Medicine of the Ministry of Education of the People's Republic of China, Guangdong Key Laboratory for translational Cancer research of Chinese Medicine, International Institute for Translational Chinese Medicine, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, 510006, China
| | - Ziwei Huang
- Joint Laboratory for Translational Cancer Research of Chinese Medicine of the Ministry of Education of the People's Republic of China, Guangdong Key Laboratory for translational Cancer research of Chinese Medicine, International Institute for Translational Chinese Medicine, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, 510006, China
| | - Yuanping Wang
- Shunde Hospital of Guangzhou University of Chinese Medicine, Guangzhou University of Chinese Medicine, Foshan, Guangdong, 528333, China; The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, China
| | - Xiaoxiao Qi
- Joint Laboratory for Translational Cancer Research of Chinese Medicine of the Ministry of Education of the People's Republic of China, Guangdong Key Laboratory for translational Cancer research of Chinese Medicine, International Institute for Translational Chinese Medicine, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, 510006, China
| | - Dawei Wang
- Shunde Hospital of Guangzhou University of Chinese Medicine, Guangzhou University of Chinese Medicine, Foshan, Guangdong, 528333, China; The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, China.
| | - Zhongqiu Liu
- Joint Laboratory for Translational Cancer Research of Chinese Medicine of the Ministry of Education of the People's Republic of China, Guangdong Key Laboratory for translational Cancer research of Chinese Medicine, International Institute for Translational Chinese Medicine, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, 510006, China; Guangdong-Hong Kong-Macau Joint Lab on Chinese Medicine and Immune Disease Research, Guangzhou Univ Chinese Med, Guangzhou, Guangdong, 510006, China.
| | - Yuanyuan Cheng
- Joint Laboratory for Translational Cancer Research of Chinese Medicine of the Ministry of Education of the People's Republic of China, Guangdong Key Laboratory for translational Cancer research of Chinese Medicine, International Institute for Translational Chinese Medicine, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, 510006, China; Guangdong-Hong Kong-Macau Joint Lab on Chinese Medicine and Immune Disease Research, Guangzhou Univ Chinese Med, Guangzhou, Guangdong, 510006, China.
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11
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Min X, Wang S, Zhang X, Sun N, Kim KM. PKCβII activation requires nuclear trafficking for phosphorylation and Mdm2-mediated ubiquitination. Life Sci Alliance 2023; 6:e202201748. [PMID: 36717249 PMCID: PMC9887771 DOI: 10.26508/lsa.202201748] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 01/11/2023] [Accepted: 01/11/2023] [Indexed: 01/31/2023] Open
Abstract
PKCβII, a conventional PKC family member, plays critical roles in the regulation of a variety of cellular functions. Here, we employed loss-of-function approaches and mutants of PKCβII with altered phosphorylation and protein interaction behaviors to identify the cellular mechanisms underlying the activation of PKCβII. Our results show that 3-phosphoinositide-dependent protein kinase-1 (PDK1)-mediated constitutive phosphorylation of PKCβII at the activation loop (T500) is required for phorbol ester-induced nuclear entry and subsequent Mdm2-mediated ubiquitination of PKCβII, whereas ubiquitination of PKCβII is required for the PDK1-mediated inducible phosphorylation of PKCβII at T500 in the nucleus. After moving out of the nucleus, PKCβII interacts with actin, undergoes inducible mTORC2-mediated phosphorylation at the turn motif (T641), interacts with clathrin, and then translocates to the plasma membrane. This overall cascade of cellular events intertwined with the phosphorylation at critical residues and Mdm2-mediated ubiquitination in the nucleus and along with interactions with actin and clathrin plays roles that encompass the core processes of PKC activation.
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Affiliation(s)
- Xiao Min
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju, Republic of Korea
| | - Shujie Wang
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju, Republic of Korea
| | - Xiaohan Zhang
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju, Republic of Korea
| | - Ningning Sun
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju, Republic of Korea
| | - Kyeong-Man Kim
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju, Republic of Korea
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Min X, Sun N, Wang S, Zhang X, Kim KM. Sequestration of Gβγ by deubiquitinated arrestins into the nucleus as a novel desensitization mechanism of G protein-coupled receptors. Cell Commun Signal 2023; 21:11. [PMID: 36658650 PMCID: PMC9854190 DOI: 10.1186/s12964-022-01013-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 12/10/2022] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Desensitization of G protein-coupled receptors (GPCRs) refers to a rapid attenuation of responsiveness that occurs with repeated or continuous exposure to agonists. GRK-mediated phosphorylation and subsequent binding with arrestins in the activated receptor cytoplasmic cavity in competition with G proteins has been suggested as the conventional mechanism of desensitization. Along with widely accepted conventional mechanism of desensitization, studies of various GPCRs including dopamine D2-like receptors (D2R, D3R, D4R) have suggested the existence of another desensitization mechanism. In this study, loss-of-function approaches and D2-like receptor mutants that display different desensitization properties were used to elucidate the molecular mechanisms responsible for desensitization. RESULTS Desensitization development entailed the signaling cascade composed of Src, PDK1, and Akt, the latter of which in turn interacted with USP33, an arrestin deubiquitinase, to promote arrestin deubiquitination. The deubiquitinated arrestin subsequently formed a complex with Gβγ and translocated to the nucleus via an importin complex, wherein it sequestered Gβγ from the receptor and Gα, thereby attenuating receptor signaling. As in D2-like receptors, both USP33 and importin β1 were involved in the desensitization of the β2 adrenoceptor. CONCLUSIONS In addition to the conventional mechanism of desensitization, which occurs on the plasma membrane and in the cytosol, this study provides a new insight that another desensitization pathway in which nuclear trafficking plays a critical role is operating. It is plausible that multiple, complementary desensitization measures are in place to properly induce desensitization depending on receptor characteristics or the surrounding environment. Video Abstract.
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Affiliation(s)
- Xiao Min
- grid.14005.300000 0001 0356 9399Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwangju, 61186 Republic of Korea
| | - Ningning Sun
- grid.14005.300000 0001 0356 9399Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwangju, 61186 Republic of Korea
| | - Shujie Wang
- grid.14005.300000 0001 0356 9399Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwangju, 61186 Republic of Korea
| | - Xiaohan Zhang
- grid.14005.300000 0001 0356 9399Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwangju, 61186 Republic of Korea ,grid.443382.a0000 0004 1804 268XCollege of Pharmaceutical Sciences, Guizhou University, Guiyang, 550025 Guizhou China
| | - Kyeong-Man Kim
- grid.14005.300000 0001 0356 9399Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwangju, 61186 Republic of Korea
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Min X, Zhang X, Wang S, Kim KM. Activation of PKCβII through nuclear trafficking guided by βγ subunits of trimeric G protein and 14-3-3ε. Life Sci 2022; 312:121245. [PMID: 36503900 DOI: 10.1016/j.lfs.2022.121245] [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: 08/24/2022] [Revised: 11/22/2022] [Accepted: 11/23/2022] [Indexed: 11/27/2022]
Abstract
AIMS Conventional members of protein kinase C (PKC) family, including PKCβII, are constitutively phosphorylated on three major motifs and located in the cytosol in a primed state. In response to cellular stimuli, PKCβII is activated through inducible phosphorylation and Mdm2-mediated ubiquitination. In this study, we aimed to identify the activation mechanism of PKCβII, focusing on the signaling cascade that regulate the phosphorylation and ubiquitination. MATERIALS AND METHODS Loss-of-function approaches and mutants of PDK1/PKCβII that display different regulatory properties were used to identify the cellular components and processes responsible for endocytosis. KEY FINDINGS Phorbol 12-myristate 13-acetate (PMA)-induced phosphorylation and ubiquitination of PKCβII, which are needed for its translocation to the plasma membrane, required the presence of both Gβγ and 14-3-3ε. Gβγ and 14-3-3ε mediated the constitutive phosphorylation of PKCβII by scaffolding PI3K and PDK1 in the cytosol, which is an inactive but required state for the activation of PKCβII by subsequent signals. In response to PMA treatment, the signaling complex translocated to the nucleus with dissociation of PI3K from it. Thereafter, PDK1 stably interacted with 14-3-3ε and was dephosphorylated; PKCβII interacted with Mdm2 along with Gβγ, leading to its ubiquitination at two lysine residues on its C-tail. Finally, PDK1/14-3-3ε and ubiquitinated PKCβII translocated to the plasma membrane. SIGNIFICANCE As PKCβII mediates a wide range of cellular functions and plays important roles in the pathogenesis of various diseases, our results will provide clues to understand the pathogenesis of PKCβII-related disorders and facilitate their treatment.
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Affiliation(s)
- Xiao Min
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju, Republic of Korea
| | - Xiaohan Zhang
- School of Pharmaceutical Sciences, Guizhou University, Guiyang 550025, China
| | - Shujie Wang
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju, Republic of Korea
| | - Kyeong-Man Kim
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju, Republic of Korea.
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Control of the Mdm2-p53 signal loop by β-arrestin 2: The ins and outs. Oncotarget 2021; 12:2543-2545. [PMID: 34966486 PMCID: PMC8711569 DOI: 10.18632/oncotarget.28065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Indexed: 11/25/2022] Open
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Acharya S, Kundu D, Kim KM. β-Arrestin1 and GPCR kinase2 play permissive roles in Src-mediated endocytosis of α4β2 nicotinic ACh receptors. Br J Pharmacol 2021; 178:3498-3516. [PMID: 33844281 DOI: 10.1111/bph.15495] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 04/02/2021] [Accepted: 04/06/2021] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND AND PURPOSE The α4β2 nicotinic ACh receptor (nAChR), a subtype of the ligand-gated ion channel, is abundantly expressed in the brain and is implicated in several neurological disorders. The endocytosis of nAChRs plays important roles in the pathogenesis of neurological diseases, but the underlying molecular mechanisms remain poorly understood. EXPERIMENTAL APPROACH Loss-of-function approaches and mutants of α4β2 nAChRs that display different endocytic properties were used to identify the cellular components and processes responsible for endocytosis. The signalling cascade that leads to endocytosis was deduced via protein interactions in predicted cellular components. The endocytosis of α4β2 nAChRs was determined and crosschecked using an ELISA and radioligand assay. KEY RESULTS Endocytosis of α4β2 nAChRs occurred through clathrin-mediated endocytosis in a dynamin-dependent manner. 14-3-3η-dependent Src-mediated phosphorylation of the nAChR α4 subunit at Y575 was required for nAChR endocytosis, and this occurred with the assistance of β-arrestin1 and GPCR kinase 2 (GRK2) without the need for kinase activity. Endocytosis triggered the mouse double minute 2 homologue-mediated ubiquitination and subsequent down-regulation of α4β2 nAChRs. CONCLUSIONS AND IMPLICATIONS α4β2 nAChR, an ionophore receptor, employs the metabotropic signalling pathway required for endocytosis, which leads to ubiquitination and down-regulation. Further, GRK2 and β-arrestin1, usually associated with GPCR signalling, are involved in the endocytosis of α4β2 nAChRs via different mechanisms. Considering the functional and pathological implications of nAChR endocytosis, results obtained in this study are crucial for the progression of basic research and clinical investigations.
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Affiliation(s)
- Srijan Acharya
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwangju, Republic of Korea.,Mitchell Cancer Institute, Department of Pathology, College of Medicine, University of South Alabama, Mobile, Alabama, USA
| | - Dooti Kundu
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwangju, Republic of Korea
| | - Kyeong-Man Kim
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwangju, Republic of Korea
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The RanBP2/RanGAP1-SUMO complex gates β-arrestin2 nuclear entry to regulate the Mdm2-p53 signaling axis. Oncogene 2021; 40:2243-2257. [PMID: 33649538 DOI: 10.1038/s41388-021-01704-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 02/04/2021] [Accepted: 02/05/2021] [Indexed: 01/31/2023]
Abstract
Mdm2 antagonizes the tumor suppressor p53. Targeting the Mdm2-p53 interaction represents an attractive approach for the treatment of cancers with functional p53. Investigating mechanisms underlying Mdm2-p53 regulation is therefore important. The scaffold protein β-arrestin2 (β-arr2) regulates tumor suppressor p53 by counteracting Mdm2. β-arr2 nucleocytoplasmic shuttling displaces Mdm2 from the nucleus to the cytoplasm resulting in enhanced p53 signaling. β-arr2 is constitutively exported from the nucleus, via a nuclear export signal, but mechanisms regulating its nuclear entry are not completely elucidated. β-arr2 can be SUMOylated, but no information is available on how SUMO may regulate β-arr2 nucleocytoplasmic shuttling. While we found β-arr2 SUMOylation to be dispensable for nuclear import, we identified a non-covalent interaction between SUMO and β-arr2, via a SUMO interaction motif (SIM), that is required for β-arr2 cytonuclear trafficking. This SIM promotes association of β-arr2 with the multimolecular RanBP2/RanGAP1-SUMO nucleocytoplasmic transport hub that resides on the cytoplasmic filaments of the nuclear pore complex. Depletion of RanBP2/RanGAP1-SUMO levels result in defective β-arr2 nuclear entry. Mutation of the SIM inhibits β-arr2 nuclear import, its ability to delocalize Mdm2 from the nucleus to the cytoplasm and enhanced p53 signaling in lung and breast tumor cell lines. Thus, a β-arr2 SIM nuclear entry checkpoint, coupled with active β-arr2 nuclear export, regulates its cytonuclear trafficking function to control the Mdm2-p53 signaling axis.
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GRK2-mediated receptor phosphorylation and Mdm2-mediated β-arrestin2 ubiquitination drive clathrin-mediated endocytosis of G protein-coupled receptors. Biochem Biophys Res Commun 2020; 533:383-390. [DOI: 10.1016/j.bbrc.2020.09.030] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 09/11/2020] [Indexed: 01/07/2023]
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Zheng M, Zhang X, Min X, Sun N, Kim KM. Cytoplasmic recruitment of Mdm2 as a common characteristic of G protein-coupled receptors that undergo desensitization. Biochem Biophys Res Commun 2020; 530:181-188. [PMID: 32828283 DOI: 10.1016/j.bbrc.2020.06.091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 06/18/2020] [Indexed: 11/18/2022]
Abstract
Desensitization of G protein-coupled receptors (GPCRs) represents a gradual attenuation of receptor responsiveness by continuous or repeated exposure to agonists. The most widely accepted molecular mechanism responsible for desensitization is that of GRK2-mediated receptor phosphorylation followed by association with β-arrestins. However, in most cases, this mechanism cannot explain the desensitization of GPCRs. In this study, we investigated whether there exists a direct correlation between desensitization and certain cellular events that commonly observed with desensitizing receptors. Our study showed that constitutive ubiquitination of β-arrestin, accompanied by nuclear to cytoplasmic translocation of Mdm2, was observed in cells expressing desensitizing GPCRs (dopamine D3 receptor, K149C-dopamine D2 receptor, β2 adrenoceptor, and lysophosphatidic acid receptor 1). In contrast, Mdm2 was observed in the nucleus in cells expressing non-desensitizing GPCRs (dopamine D2 receptor, C147K-dopamine D3 receptor, and dopamine D4 receptor). Molecular manipulation to convert the characteristics of the dopamine D4 receptor from non-desensitizing to desensitizing changed the status of subcellular localization of Mdm2 from nuclear to cytoplasmic. With repeated agonist treatments of desensitizing receptors, Mdm2 translocated from cytoplasm to nucleus, resulting in the deubiquitination of β-arrestins. This study suggests that the property of a receptor that causes a change in subcellular localization of Mdm2, from the nuclear to cytoplasmic, could be used as a biomarker to predict the desensitization of a receptor.
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Affiliation(s)
- Mei Zheng
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju, 61186, Republic of Korea
| | - Xiaohan Zhang
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju, 61186, Republic of Korea
| | - Xiao Min
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju, 61186, Republic of Korea
| | - Ningning Sun
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju, 61186, Republic of Korea
| | - Kyeong-Man Kim
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju, 61186, Republic of Korea.
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