1
|
Allen BG, Merlen C, Branco AF, Pétrin D, Hébert TE. Understanding the impact of nuclear-localized GPCRs on cellular signalling. Cell Signal 2024; 123:111358. [PMID: 39181220 DOI: 10.1016/j.cellsig.2024.111358] [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: 07/24/2024] [Revised: 08/14/2024] [Accepted: 08/20/2024] [Indexed: 08/27/2024]
Abstract
G protein-coupled receptors (GPCRs) have historically been associated with signalling events driven from the plasma membrane. More recently, signalling from endosomes has been recognized as a feature of internalizing receptors. However, there was little consideration given to the notion that GPCRs can be targeted to distinct subcellular locations that did not involve an initial trafficking to the cell surface. Here, we focus on the evidence for and the potential impact of GPCR signalling specifically initiated from the nuclear membrane. We also discuss the possibilities for selectively targeting this and other internal pools of receptors as novel venues for drug discovery.
Collapse
Affiliation(s)
- Bruce G Allen
- Montreal Heart Institute, Montréal, Québec H1T 1C8, Canada; Departments of Biochemistry and Molecular Medicine, Medicine, Pharmacology and Physiology, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | | | - Ana F Branco
- Montreal Heart Institute, Montréal, Québec H1T 1C8, Canada
| | - Darlaine Pétrin
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada
| | - Terence E Hébert
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada.
| |
Collapse
|
2
|
Zhang F, Armando I, Jose PA, Zeng C, Yang J. G protein-coupled receptor kinases in hypertension: physiology, pathogenesis, and therapeutic targets. Hypertens Res 2024; 47:2317-2336. [PMID: 38961282 PMCID: PMC11374685 DOI: 10.1038/s41440-024-01763-y] [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: 11/17/2023] [Revised: 05/10/2024] [Accepted: 06/06/2024] [Indexed: 07/05/2024]
Abstract
G protein-coupled receptors (GPCRs) mediate cellular responses to a myriad of hormones and neurotransmitters that play vital roles in the regulation of physiological processes such as blood pressure. In organs such as the artery and kidney, hormones or neurotransmitters, such as angiotensin II (Ang II), dopamine, epinephrine, and norepinephrine exert their functions via their receptors, with the ultimate effect of keeping normal vascular reactivity, normal body sodium, and normal blood pressure. GPCR kinases (GRKs) exert their biological functions, by mediating the regulation of agonist-occupied GPCRs, non-GPCRs, or non-receptor substrates. In particular, increasing number of studies show that aberrant expression and activity of GRKs in the cardiovascular system and kidney inhibit or stimulate GPCRs (e.g., dopamine receptors, Ang II receptors, and α- and β-adrenergic receptors), resulting in hypertension. Current studies focus on the effect of selective GRK inhibitors in cardiovascular diseases, including hypertension. Moreover, genetic studies show that GRK gene variants are associated with essential hypertension, blood pressure response to antihypertensive medicines, and adverse cardiovascular outcomes of antihypertensive treatment. In this review, we present a comprehensive overview of GRK-mediated regulation of blood pressure, role of GRKs in the pathogenesis of hypertension, and highlight potential strategies for the treatment of hypertension. Schematic representation of GPCR desensitization process. Activation of GPCRs begins with the binding of an agonist to its corresponding receptor. Then G proteins activate downstream effectors that are mediated by various signaling pathways. GPCR signaling is halted by GRK-mediated receptor phosphorylation, which causes receptor internalization through β-arrestin.
Collapse
Affiliation(s)
- Fuwei Zhang
- Research Center for Metabolic and Cardiovascular Diseases, The Third Affiliated Hospital of Chongqing Medical University, Chongqing, PR China
- Department of Nutrition, The Third Affiliated Hospital of Chongqing Medical University, Chongqing, PR China
- Department of Cardiology, The Third Affiliated Hospital of Chongqing Medical University, Chongqing, PR China
| | - Ines Armando
- Division of Renal Diseases & Hypertension, Department of Medicine and Department of Physiology/Pharmacology, The George Washington University School of Medicine & Health Sciences, Washington, DC, USA
| | - Pedro A Jose
- Division of Renal Diseases & Hypertension, Department of Medicine and Department of Physiology/Pharmacology, The George Washington University School of Medicine & Health Sciences, Washington, DC, USA
| | - Chunyu Zeng
- Department of Cardiology, Daping Hospital, The Third Military Medical University (Army Medical University), Chongqing, PR China
- Chongqing Key Laboratory for Hypertension Research, Chongqing Cardiovascular Clinical Research Center, Chongqing Institute of Cardiology, Chongqing, PR China
| | - Jian Yang
- Research Center for Metabolic and Cardiovascular Diseases, The Third Affiliated Hospital of Chongqing Medical University, Chongqing, PR China.
- Department of Nutrition, The Third Affiliated Hospital of Chongqing Medical University, Chongqing, PR China.
| |
Collapse
|
3
|
Marzano F, Liccardo D, Elia A, Mucio I, de Lucia C, Lucchese AM, Gao E, Ferrara N, Rapacciuolo A, Paolocci N, Rengo G, Koch WJ, Cannavo A. Genetic Catalytic Inactivation of GRK5 Impairs Cardiac Function in Mice Via Dysregulated P53 Levels. JACC. BASIC TO TRANSLATIONAL SCIENCE 2022; 7:366-380. [PMID: 35540100 PMCID: PMC9079799 DOI: 10.1016/j.jacbts.2022.01.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 12/31/2021] [Accepted: 01/03/2022] [Indexed: 02/08/2023]
Abstract
GRK5's catalytic activity in regulating basal and stressed cardiac function has not been studied. Herein, we studied knock-in mice in which GRK5 was mutated to render it catalytically inactive (K215R). At baseline, GRK5-K215R mice showed a marked decline in cardiac function with increased apoptosis and fibrosis. In vitro, restriction of GRK5 inside the nucleus of cardiomyocytes resulted in enhanced cell death along with higher p53 levels. Moreover, in fibroblasts, we demonstrated that K215R mutation promoted the transition into myofibroblast phenotype. This study provides novel insight into the biological actions of GRK5, that are essential for its future targeting.
Collapse
Affiliation(s)
- Federica Marzano
- Department of Advanced Biomedical Sciences, Federico II University of Naples, Naples, Italy
| | - Daniela Liccardo
- Department of Translational Medical Sciences, Federico II University of Naples, Naples, Italy
| | - Andrea Elia
- Department of Translational Medical Sciences, Federico II University of Naples, Naples, Italy
| | - Ines Mucio
- Department of Translational Medical Sciences, Federico II University of Naples, Naples, Italy
| | - Claudio de Lucia
- Center for Translational Medicine and Department of Pharmacology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania, USA
| | - Anna Maria Lucchese
- Center for Translational Medicine and Department of Pharmacology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania, USA
| | - Erhe Gao
- Center for Translational Medicine and Department of Pharmacology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania, USA
| | - Nicola Ferrara
- Department of Translational Medical Sciences, Federico II University of Naples, Naples, Italy,Istituti Clinici Scientifici ICS-Maugeri, Telese Terme (BN), Italy
| | - Antonio Rapacciuolo
- Department of Advanced Biomedical Sciences, Federico II University of Naples, Naples, Italy
| | - Nazareno Paolocci
- Division of Cardiology, Johns Hopkins University Medical Institutions, Baltimore, Maryland, USA,Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Giuseppe Rengo
- Department of Translational Medical Sciences, Federico II University of Naples, Naples, Italy,Istituti Clinici Scientifici ICS-Maugeri, Telese Terme (BN), Italy
| | - Walter J. Koch
- Division of Cardiology, Johns Hopkins University Medical Institutions, Baltimore, Maryland, USA,Address for correspondence: Dr Walter J. Koch, Department of Pharmacology, Center for Translational Medicine, Lewis Katz School of Medicine, Temple University, 3500 North Broad Street, MERB 941, Philadelphia, Pennsylvania 19140, USA.
| | - Alessandro Cannavo
- Department of Translational Medical Sciences, Federico II University of Naples, Naples, Italy,Dr Alessandro Cannavo, Federico II University of Naples, Department of Translational Medical Sciences, Via S. Pansini, 5, 80131 Naples, Italy.
| |
Collapse
|
4
|
GRK6 regulates the hemostatic response to injury through its rate-limiting effects on GPCR signaling in platelets. Blood Adv 2021; 4:76-86. [PMID: 31899801 DOI: 10.1182/bloodadvances.2019000467] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 11/25/2019] [Indexed: 12/18/2022] Open
Abstract
G protein-coupled receptors (GPCRs) mediate the majority of platelet activation in response to agonists. However, questions remain regarding the mechanisms that provide negative feedback toward activated GPCRs to limit platelet activation and thrombus formation. Here we provide the first evidence that GPCR kinase 6 (GRK6) serves this role in platelets, using GRK6-/- mice generated by CRISPR-Cas9 genome editing to examine the consequences of GRK6 knockout on GPCR-dependent signaling. Hemostatic thrombi formed in GRK6-/- mice are larger than in wild-type (WT) controls during the early stages of thrombus formation, with a rapid increase in platelet accumulation at the site of injury. GRK6-/- platelets have increased platelet activation, but in an agonist-selective manner. Responses to PAR4 agonist or adenosine 5'-diphosphate stimulation in GRK6-/- platelets are increased compared with WT littermates, whereas the response to thromboxane A2 (TxA2) is normal. Underlying these changes in GRK6-/- platelets is an increase in Ca2+ mobilization, Akt activation, and granule secretion. Furthermore, deletion of GRK6 in human MEG-01 cells causes an increase in Ca2+ response and PAR1 surface expression in response to thrombin. Finally, we show that human platelet activation in response to thrombin causes an increase in binding of GRK6 to PAR1, as well as an increase in the phosphorylation of PAR1. Deletion of GRK6 in MEG-01 cells causes a decrease in PAR1 phosphorylation. Taken together, these data show that GRK6 regulates the hemostatic response to injury through PAR- and P2Y12-mediated effects, helping to limit the rate of platelet activation during thrombus growth and prevent inappropriate platelet activation.
Collapse
|
5
|
Coleman RC, Eguchi A, Lieu M, Roy R, Barr EW, Ibetti J, Lucchese AM, Peluzzo AM, Gresham K, Chuprun JK, Koch WJ. A peptide of the N terminus of GRK5 attenuates pressure-overload hypertrophy and heart failure. Sci Signal 2021; 14:14/676/eabb5968. [PMID: 33785612 DOI: 10.1126/scisignal.abb5968] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Aberrant changes in gene expression underlie the pathogenesis and progression of pressure-overload heart failure, leading to maladaptive cardiac hypertrophy, ventricular remodeling, and contractile dysfunction. Signaling through the G protein Gq triggers maladaptation and heart failure, in part through the activation of G protein-coupled receptor kinase 5 (GRK5). Hypertrophic stimuli induce the accumulation of GRK5 in the nuclei of cardiomyocytes, where it regulates pathological gene expression through multiple transcription factors including NFAT. The nuclear targeting of GRK5 is mediated by an amino-terminal (NT) domain that binds to calmodulin (CaM). Here, we sought to prevent GRK5-mediated pathology in pressure-overload maladaptation and heart failure by expressing in cardiomyocytes a peptide encoding the GRK5 NT (GRK5nt) that encompasses the CaM binding domain. In cultured cardiomyocytes, GRK5nt expression abrogated Gq-coupled receptor-mediated hypertrophy, including attenuation of pathological gene expression and the transcriptional activity of NFAT and NF-κB. We confirmed that GRK5nt bound to and blocked Ca2+-CaM from associating with endogenous GRK5, thereby preventing GRK5 nuclear accumulation after pressure overload. We generated mice that expressed GRKnt in a cardiac-specific fashion (TgGRK5nt mice), which exhibited reduced cardiac hypertrophy, ventricular dysfunction, pulmonary congestion, and cardiac fibrosis after chronic transverse aortic constriction. Together, our data support a role for GRK5nt as an inhibitor of pathological GRK5 signaling that prevents heart failure.
Collapse
Affiliation(s)
- Ryan C Coleman
- Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Akito Eguchi
- Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Melissa Lieu
- Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Rajika Roy
- Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Eric W Barr
- Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Jessica Ibetti
- Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Anna-Maria Lucchese
- Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Amanda M Peluzzo
- Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Kenneth Gresham
- Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - J Kurt Chuprun
- Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Walter J Koch
- Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA.
| |
Collapse
|
6
|
Rukavina Mikusic NL, Silva MG, Pineda AM, Gironacci MM. Angiotensin Receptors Heterodimerization and Trafficking: How Much Do They Influence Their Biological Function? Front Pharmacol 2020; 11:1179. [PMID: 32848782 PMCID: PMC7417933 DOI: 10.3389/fphar.2020.01179] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Accepted: 07/20/2020] [Indexed: 01/03/2023] Open
Abstract
G-protein–coupled receptors (GPCRs) are targets for around one third of currently approved and clinical prescribed drugs and represent the largest and most structurally diverse family of transmembrane signaling proteins, with almost 1000 members identified in the human genome. Upon agonist stimulation, GPCRs are internalized and trafficked inside the cell: they may be targeted to different organelles, recycled back to the plasma membrane or be degraded. Once inside the cell, the receptors may initiate other signaling pathways leading to different biological responses. GPCRs’ biological function may also be influenced by interaction with other receptors. Thus, the ultimate cellular response may depend not only on the activation of the receptor from the cell membrane, but also from receptor trafficking and/or the interaction with other receptors. This review is focused on angiotensin receptors and how their biological function is influenced by trafficking and interaction with others receptors.
Collapse
Affiliation(s)
- Natalia L Rukavina Mikusic
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Dpto. Química Biológica, IQUIFIB (UBA-CONICET), Buenos Aires, Argentina
| | - Mauro G Silva
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Dpto. Química Biológica, IQUIFIB (UBA-CONICET), Buenos Aires, Argentina
| | - Angélica M Pineda
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Dpto. Química Biológica, IQUIFIB (UBA-CONICET), Buenos Aires, Argentina
| | - Mariela M Gironacci
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Dpto. Química Biológica, IQUIFIB (UBA-CONICET), Buenos Aires, Argentina
| |
Collapse
|
7
|
Grisanti LA, Schumacher SM, Tilley DG, Koch WJ. Designer Approaches for G Protein-Coupled Receptor Modulation for Cardiovascular Disease. JACC Basic Transl Sci 2018; 3:550-562. [PMID: 30175279 PMCID: PMC6115700 DOI: 10.1016/j.jacbts.2017.12.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 12/14/2017] [Indexed: 12/17/2022]
Abstract
The new horizon for cardiac therapy may lie beneath the surface, with the downstream mediators of G protein–coupled receptor (GPCR) activity. Targeted approaches have shown that receptor activation may be biased toward signaling through G proteins or through GPCR kinases (GRKs) and β-arrestins, with divergent functional outcomes. In addition to these canonical roles, numerous noncanonical activities of GRKs and β-arrestins have been demonstrated to modulate GPCR signaling at all levels of receptor activation and regulation. Further, research continues to identify novel GRK/effector and β-arrestin/effector complexes with distinct impacts on cardiac function in the normal heart and the diseased heart. Coupled with the identification of once orphan receptors and endogenous ligands with beneficial cardiovascular effects, this expands the repertoire of GPCR targets. Together, this research highlights the potential for focused therapeutic activation of beneficial pathways, with simultaneous exclusion or inhibition of detrimental signaling, and represents a new wave of therapeutic development.
Collapse
Key Words
- AR, adrenergic receptor
- AT1R, angiotensin II type 1A receptor
- CRF, corticotropin-releasing factor
- EGFR, epidermal growth factor receptor
- ERK1/2, extracellular signal-regulated kinase
- G protein–coupled receptor kinases
- G protein–coupled receptors
- GPCR, G protein–coupled receptor
- GRK, G protein–coupled receptor kinase
- HF, heart failure
- ICL, intracellular loop
- PI3K, phosphoinositide 3-kinase
- SERCA2a, sarco(endo)plasmic reticulum Ca2+-ATPase
- SII, [Sar(1), Ile (4), Ile(8)]-angiotensin II
- biased ligands
Collapse
Affiliation(s)
- Laurel A Grisanti
- Center for Translational Medicine and Department of Pharmacology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania.,Department of Biomedical Sciences, University of Missouri, Columbia, Missouri
| | - Sarah M Schumacher
- Center for Translational Medicine and Department of Pharmacology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania.,Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Douglas G Tilley
- Center for Translational Medicine and Department of Pharmacology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania
| | - Walter J Koch
- Center for Translational Medicine and Department of Pharmacology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania
| |
Collapse
|
8
|
Abstract
G protein-coupled receptor kinases (GRKs) are classically known for their role in regulating the activity of the largest known class of membrane receptors, which influence diverse biological processes in every cell type in the human body. As researchers have tried to uncover how this family of kinases, containing only 7 members, achieves selective and coordinated control of receptors, they have uncovered a growing number of noncanonical activities for these kinases. These activities include phosphorylation of nonreceptor targets and kinase-independent molecular interactions. In particular, GRK2, GRK3, and GRK5 are the predominant members expressed in the heart. Their canonical and noncanonical actions within cardiac and other tissues have significant implications for cardiovascular function in healthy animals and for the development and progression of disease. This review summarizes what is currently known regarding the activity of these kinases, and particularly the role of GRK2 and GRK5 in the molecular alterations that occur during heart failure. This review further highlights areas of GRK regulation that remain poorly understood and how they may represent novel targets for therapeutic development.
Collapse
|
9
|
Yang J, Villar VAM, Armando I, Jose PA, Zeng C. G Protein-Coupled Receptor Kinases: Crucial Regulators of Blood Pressure. J Am Heart Assoc 2016; 5:JAHA.116.003519. [PMID: 27390269 PMCID: PMC5015388 DOI: 10.1161/jaha.116.003519] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Jian Yang
- Department of Nutrition, Daping Hospital, The Third Military Medical University, Chongqing, China Department of Cardiology, Chongqing Key Laboratory for Hypertension, Chongqing Institute of Cardiology, Chongqing Cardiovascular Clinical Research Center, Daping Hospital, The Third Military Medical University, Chongqing, China
| | - Van Anthony M Villar
- Division of Renal Diseases & Hypertension, Department of Medicine, The George Washington University School of Medicine and Health Sciences, Washington, DC
| | - Ines Armando
- Division of Renal Diseases & Hypertension, Department of Medicine, The George Washington University School of Medicine and Health Sciences, Washington, DC
| | - Pedro A Jose
- Division of Renal Diseases & Hypertension, Department of Medicine, The George Washington University School of Medicine and Health Sciences, Washington, DC Department of Pharmacology and Physiology, The George Washington University School of Medicine and Health Sciences, Washington, DC
| | - Chunyu Zeng
- Department of Cardiology, Chongqing Key Laboratory for Hypertension, Chongqing Institute of Cardiology, Chongqing Cardiovascular Clinical Research Center, Daping Hospital, The Third Military Medical University, Chongqing, China
| |
Collapse
|
10
|
Hullmann J, Traynham CJ, Coleman RC, Koch WJ. The expanding GRK interactome: Implications in cardiovascular disease and potential for therapeutic development. Pharmacol Res 2016; 110:52-64. [PMID: 27180008 DOI: 10.1016/j.phrs.2016.05.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 05/05/2016] [Indexed: 12/11/2022]
Abstract
Heart failure (HF) is a global epidemic with the highest degree of mortality and morbidity of any disease presently studied. G protein-coupled receptors (GPCRs) are prominent regulators of cardiovascular function. Activated GPCRs are "turned off" by GPCR kinases (GRKs) in a process known as "desensitization". GRKs 2 and 5 are highly expressed in the heart, and known to be upregulated in HF. Over the last 20 years, both GRK2 and GRK5 have been demonstrated to be critical mediators of the molecular alterations that occur in the failing heart. In the present review, we will highlight recent findings that further characterize "non-canonical" GRK signaling observed in HF. Further, we will also present potential therapeutic strategies (i.e. small molecule inhibition, microRNAs, gene therapy) that may have potential in combating the deleterious effects of GRKs in HF.
Collapse
Affiliation(s)
| | - Christopher J Traynham
- Center for Translational Medicine, Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140, United States
| | - Ryan C Coleman
- Center for Translational Medicine, Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140, United States
| | - Walter J Koch
- Center for Translational Medicine, Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140, United States.
| |
Collapse
|
11
|
Ye B, Hou N, Xiao L, Xu Y, Xu H, Li F. Dynamic monitoring of oxidative DNA double-strand break and repair in cardiomyocytes. Cardiovasc Pathol 2016; 25:93-100. [PMID: 26764141 PMCID: PMC4801000 DOI: 10.1016/j.carpath.2015.10.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 10/28/2015] [Accepted: 10/29/2015] [Indexed: 11/30/2022] Open
Abstract
DNA double-strand breaks (DSBs) are most dangerous lesions. To determine whether oxidative stress can induce DSBs and how they are repaired in cardiomyocytes (CMs), cultured neonatal rat CMs were treated with different doses of H2O2 and followed for up to 72 h for monitoring the spatiotemporal dynamics of DNA repair protein assembly/disassembly at DSB foci. The protein levels and foci numbers of histone H2AX phosphorylated at serine 139 (γ-H2AX) increased proportionally to 50, 100, and 200 μmol/L H2O2 after 30 min treatment. When H2O2 was at or above 400 μmol/L, γ-H2AX became predominantly pannuclear. After 30 min, 200 μmol/L of H2O2 treatment, γ-H2AX levels were highest within the first hour and then gradually declined during the recovery and returned to basal levels at 48 h. Among DNA damage transducer kinases, ataxia telangiectasia mutated (ATM) was significantly activated by H2O2 in contrast to mild activation of ATR (ATM and Rad3-related). A DSB binding protein, p53 binding protein 1, formed distinct nuclear foci that colocalized with γ-H2AX foci and phosphorylated ATM. Our findings indicate that DSBs can be induced by H2O2 and ATM is the main kinase to mediate DSB repair in CMs. Therefore, monitoring DSB repair can assess oxidative injury and response in CMs.
Collapse
Affiliation(s)
- Bo Ye
- Department of Laboratory Medicine and Pathology, University of Minnesota, Room 293, Dwan Variety Club Cardiovascular Research Center, 425 East River Parkway, Minneapolis, MN 55455, USA; Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Ning Hou
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Lu Xiao
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Yifan Xu
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Haodong Xu
- Department of Pathology and Laboratory Medicine, UCLA Center for the Health Science, Room 13-145E, 10833 Le Conte Avenue, Los Angeles, CA 90095, USA
| | - Faqian Li
- Department of Laboratory Medicine and Pathology, University of Minnesota, Room 293, Dwan Variety Club Cardiovascular Research Center, 425 East River Parkway, Minneapolis, MN 55455, USA; Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA.
| |
Collapse
|
12
|
Traynham CJ, Hullmann J, Koch WJ. "Canonical and non-canonical actions of GRK5 in the heart". J Mol Cell Cardiol 2016; 92:196-202. [PMID: 26829117 PMCID: PMC4789097 DOI: 10.1016/j.yjmcc.2016.01.027] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Revised: 01/13/2016] [Accepted: 01/28/2016] [Indexed: 01/13/2023]
Abstract
As the average world-wide lifespan continues to increase, heart failure (HF) has dramatically increased in incidence leading to the highest degree of mortality and morbidity of any disease presently studied. G protein-coupled receptors (GPCRs) play a prominent role in regulation of cardiovascular function. GPCRs are effectively "turned off" by GPCR kinases (GRKs) in a process known as "desensitization". GRKs 2 and 5 are highly expressed in the heart, and known to be upregulated in HF. Over the last 20years, the role of GRK2 in HF has been widely studied. However, until recently, the role of GRK5 in cardiac pathophysiology had yet to be elucidated. In the present review, we will focus on GRK5's role in the myocardium in normal physiology, and its apparent critical role in the progression of HF. Further, we will also present potential therapeutic strategies (i.e. small molecule inhibition, gene therapy) that may have potential in combating the deleterious effects of GRK5 in HF.
Collapse
Affiliation(s)
- Christopher J Traynham
- Center for Translational Medicine, Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140, United States
| | | | - Walter J Koch
- Center for Translational Medicine, Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140, United States.
| |
Collapse
|
13
|
Homan KT, Waldschmidt HV, Glukhova A, Cannavo A, Song J, Cheung JY, Koch WJ, Larsen SD, Tesmer JJG. Crystal Structure of G Protein-coupled Receptor Kinase 5 in Complex with a Rationally Designed Inhibitor. J Biol Chem 2015; 290:20649-20659. [PMID: 26032411 DOI: 10.1074/jbc.m115.647370] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Indexed: 11/06/2022] Open
Abstract
G protein-coupled receptor kinases (GRKs) regulate cell signaling by initiating the desensitization of active G protein-coupled receptors. The two most widely expressed GRKs (GRK2 and GRK5) play a role in cardiovascular disease and thus represent important targets for the development of novel therapeutic drugs. In the course of a GRK2 structure-based drug design campaign, one inhibitor (CCG215022) exhibited nanomolar IC50 values against both GRK2 and GRK5 and good selectivity against other closely related kinases such as GRK1 and PKA. Treatment of murine cardiomyocytes with CCG215022 resulted in significantly increased contractility at 20-fold lower concentrations than paroxetine, an inhibitor with more modest selectivity for GRK2. A 2.4 Å crystal structure of the GRK5·CCG215022 complex was determined and revealed that the inhibitor binds in the active site similarly to its parent compound GSK180736A. As designed, its 2-pyridylmethyl amide side chain occupies the hydrophobic subsite of the active site where it forms three additional hydrogen bonds, including one with the catalytic lysine. The overall conformation of the GRK5 kinase domain is similar to that of a previously determined structure of GRK6 in what is proposed to be its active state, but the C-terminal region of the enzyme adopts a distinct conformation. The kinetic properties of site-directed mutants in this region are consistent with the hypothesis that this novel C-terminal structure is representative of the membrane-bound conformation of the enzyme.
Collapse
Affiliation(s)
- Kristoff T Homan
- Life Sciences Institute and the Departments of Pharmacology and Biological Sciences, University of Michigan, Ann Arbor, Michigan 48109
| | - Helen V Waldschmidt
- Vahlteich Medicinal Chemistry Core and the Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109
| | - Alisa Glukhova
- Life Sciences Institute and the Departments of Pharmacology and Biological Sciences, University of Michigan, Ann Arbor, Michigan 48109
| | - Alessandro Cannavo
- Center for Translational Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania 19140
| | - Jianliang Song
- Center for Translational Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania 19140
| | - Joseph Y Cheung
- Center for Translational Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania 19140
| | - Walter J Koch
- Center for Translational Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania 19140
| | - Scott D Larsen
- Vahlteich Medicinal Chemistry Core and the Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109
| | - John J G Tesmer
- Life Sciences Institute and the Departments of Pharmacology and Biological Sciences, University of Michigan, Ann Arbor, Michigan 48109.
| |
Collapse
|
14
|
Sato PY, Chuprun JK, Schwartz M, Koch WJ. The evolving impact of g protein-coupled receptor kinases in cardiac health and disease. Physiol Rev 2015; 95:377-404. [PMID: 25834229 PMCID: PMC4551214 DOI: 10.1152/physrev.00015.2014] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
G protein-coupled receptors (GPCRs) are important regulators of various cellular functions via activation of intracellular signaling events. Active GPCR signaling is shut down by GPCR kinases (GRKs) and subsequent β-arrestin-mediated mechanisms including phosphorylation, internalization, and either receptor degradation or resensitization. The seven-member GRK family varies in their structural composition, cellular localization, function, and mechanism of action (see sect. II). Here, we focus our attention on GRKs in particular canonical and novel roles of the GRKs found in the cardiovascular system (see sects. III and IV). Paramount to overall cardiac function is GPCR-mediated signaling provided by the adrenergic system. Overstimulation of the adrenergic system has been highly implicated in various etiologies of cardiovascular disease including hypertension and heart failure. GRKs acting downstream of heightened adrenergic signaling appear to be key players in cardiac homeostasis and disease progression, and herein we review the current data on GRKs related to cardiac disease and discuss their potential in the development of novel therapeutic strategies in cardiac diseases including heart failure.
Collapse
Affiliation(s)
- Priscila Y Sato
- Center for Translational Medicine and Department of Pharmacology, Temple University School of Medicine, Philadelphia, Pennsylvania; and Advanced Institutes of Convergence Technology, Suwon, South Korea
| | - J Kurt Chuprun
- Center for Translational Medicine and Department of Pharmacology, Temple University School of Medicine, Philadelphia, Pennsylvania; and Advanced Institutes of Convergence Technology, Suwon, South Korea
| | - Mathew Schwartz
- Center for Translational Medicine and Department of Pharmacology, Temple University School of Medicine, Philadelphia, Pennsylvania; and Advanced Institutes of Convergence Technology, Suwon, South Korea
| | - Walter J Koch
- Center for Translational Medicine and Department of Pharmacology, Temple University School of Medicine, Philadelphia, Pennsylvania; and Advanced Institutes of Convergence Technology, Suwon, South Korea
| |
Collapse
|
15
|
Gold JI, Martini JS, Hullmann J, Gao E, Chuprun JK, Lee L, Tilley DG, Rabinowitz JE, Bossuyt J, Bers DM, Koch WJ. Nuclear translocation of cardiac G protein-Coupled Receptor kinase 5 downstream of select Gq-activating hypertrophic ligands is a calmodulin-dependent process. PLoS One 2013; 8:e57324. [PMID: 23472081 PMCID: PMC3589474 DOI: 10.1371/journal.pone.0057324] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2012] [Accepted: 01/21/2013] [Indexed: 01/08/2023] Open
Abstract
G protein-Coupled Receptors (GPCRs) kinases (GRKs) play a crucial role in regulating cardiac hypertrophy. Recent data from our lab has shown that, following ventricular pressure overload, GRK5, a primary cardiac GRK, facilitates maladaptive myocyte growth via novel nuclear localization. In the nucleus, GRK5’s newly discovered kinase activity on histone deacetylase 5 induces hypertrophic gene transcription. The mechanisms governing the nuclear targeting of GRK5 are unknown. We report here that GRK5 nuclear accumulation is dependent on Ca2+/calmodulin (CaM) binding to a specific site within the amino terminus of GRK5 and this interaction occurs after selective activation of hypertrophic Gq-coupled receptors. Stimulation of myocytes with phenylephrine or angiotensinII causes GRK5 to leave the sarcolemmal membrane and accumulate in the nucleus, while the endothelin-1 does not cause nuclear GRK5 localization. A mutation within the amino-terminus of GRK5 negating CaM binding attenuates GRK5 movement from the sarcolemma to the nucleus and, importantly, overexpression of this mutant does not facilitate cardiac hypertrophy and related gene transcription in vitro and in vivo. Our data reveal that CaM binding to GRK5 is a physiologically relevant event that is absolutely required for nuclear GRK5 localization downstream of hypertrophic stimuli, thus facilitating GRK5-dependent regulation of maladaptive hypertrophy.
Collapse
Affiliation(s)
- Jessica I. Gold
- Center for Translational Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Jeffrey S. Martini
- Center for Translational Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Jonathan Hullmann
- Center for Translational Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Erhe Gao
- Center for Translational Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - J. Kurt Chuprun
- Center for Translational Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Linda Lee
- Department of Pharmacology, University of California Davis, Davis, California, United States of America
| | - Douglas G. Tilley
- Center for Translational Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania, United States of America
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Joseph E. Rabinowitz
- Center for Translational Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania, United States of America
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Julie Bossuyt
- Department of Pharmacology, University of California Davis, Davis, California, United States of America
| | - Donald M. Bers
- Department of Pharmacology, University of California Davis, Davis, California, United States of America
| | - Walter J. Koch
- Center for Translational Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
- Center for Translational Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania, United States of America
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, Pennsylvania, United States of America
- * E-mail:
| |
Collapse
|
16
|
Vaniotis G, Allen BG, Hébert TE. Nuclear GPCRs in cardiomyocytes: an insider's view of β-adrenergic receptor signaling. Am J Physiol Heart Circ Physiol 2011; 301:H1754-64. [PMID: 21890692 DOI: 10.1152/ajpheart.00657.2011] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
In recent years, we have come to appreciate the complexity of G protein-coupled receptor signaling in general and β-adrenergic receptor (β-AR) signaling in particular. Starting originally from three β-AR subtypes expressed in cardiomyocytes with relatively simple, linear signaling cascades, it is now clear that there are large receptor-based networks which provide a rich and diverse set of responses depending on their complement of signaling partners and the physiological state. More recently, it has become clear that subcellular localization of these signaling complexes also enriches the diversity of phenotypic outcomes. Here, we review our understanding of the signaling repertoire controlled by nuclear β-AR subtypes as well our understanding of the novel roles for G proteins themselves in the nucleus, with a special focus, where possible, on their effects in cardiomyocytes. Finally, we discuss the potential pathological implications of alterations in nuclear β-AR signaling.
Collapse
|
17
|
Huang ZM, Gold JI, Koch WJ. G protein-coupled receptor kinases in normal and failing myocardium. Front Biosci (Landmark Ed) 2011; 16:3047-60. [PMID: 21622221 DOI: 10.2741/3898] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Heart failure (HF) is the end stage of many underlying cardiovascular diseases and is among the leading causes of morbidity and mortality in industrialized countries. One of the striking characteristics of HF is the desensitization of G protein-coupled receptor (GPCR) signaling, particularly the beta-adrenergic receptor (betaAR) system. GPCR desensitization is initiated by phosphorylation by GPCR kinases (GRKs), followed by downregulation and functional uncoupling from their G proteins. In the heart, the major GRK isoforms, GRK2 and GRK5, undergo upregulation due to the heightened sympathetic nervous system activity that is characteristic of HF as catecholamine levels increase in an effort to drive the failing pump. This desensitization leads to the distinctive loss of inotropic reserve and functional capacity of the failing heart. Moreover, GRK2 and GRK5 have an increasing non-GPCR interactome, which may play critical roles in cardiac physiology. In the current review, the canonical GPCR kinase function of GRKs and the novel non-GPCR kinase activity of GRKs, their contribution to the pathogenesis of cardiac hypertrophy and HF, and the possibility of GRKs serving as future drug targets will be discussed.
Collapse
Affiliation(s)
- Zheng Maggie Huang
- Center for Translational Medicine and George Zallie and Family Laboratory for Cardiovascular Gene Therapy, Department of Medicine, Thomas Jefferson University, Philadelphia, PA, USA
| | | | | |
Collapse
|
18
|
Vaniotis G, Del Duca D, Trieu P, Rohlicek CV, Hébert TE, Allen BG. Nuclear β-adrenergic receptors modulate gene expression in adult rat heart. Cell Signal 2010; 23:89-98. [PMID: 20732414 DOI: 10.1016/j.cellsig.2010.08.007] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Revised: 08/05/2010] [Accepted: 08/16/2010] [Indexed: 01/26/2023]
Abstract
Both β(1)- and β(3)-adrenergic receptors (β(1)ARs and β(3)ARs) are present on nuclear membranes in adult ventricular myocytes. These nuclear-localized receptors are functional with respect to ligand binding and effector activation. In isolated cardiac nuclei, the non-selective βAR agonist isoproterenol stimulated de novo RNA synthesis measured using assays of transcription initiation (Boivin et al., 2006 Cardiovasc Res. 71:69-78). In contrast, stimulation of endothelin receptors, another G protein-coupled receptor (GPCR) that localizes to the nuclear membrane, resulted in decreased RNA synthesis. To investigate the signalling pathway(s) involved in GPCR-mediated regulation of RNA synthesis, nuclei were isolated from intact adult rat hearts and treated with receptor agonists in the presence or absence of inhibitors of different mitogen-activated protein kinase (MAPK) and PI3K/PKB pathways. Components of p38, JNK, and ERK1/2 MAP kinase cascades as well as PKB were detected in nuclear preparations. Inhibition of PKB with triciribine, in the presence of isoproterenol, converted the activation of the βAR from stimulatory to inhibitory with regards to RNA synthesis, while ERK1/2, JNK and p38 inhibition reduced both basal and isoproterenol-stimulated activity. Analysis by qPCR indicated an increase in the expression of 18S rRNA following isoproterenol treatment and a decrease in NFκB mRNA. Further qPCR experiments revealed that isoproterenol treatment also reduced the expression of several other genes involved in the activation of NFκB, while ERK1/2 and PKB inhibition substantially reversed this effect. Our results suggest that GPCRs on the nuclear membrane regulate nuclear functions such as gene expression and this process is modulated by activation/inhibition of downstream protein kinases within the nucleus.
Collapse
Affiliation(s)
- George Vaniotis
- Department of Biochemistry, Université de Montréal, Montréal, Québec, Canada
| | | | | | | | | | | |
Collapse
|
19
|
Chen X, Zhu H, Yuan M, Fu J, Zhou Y, Ma L. G-protein-coupled receptor kinase 5 phosphorylates p53 and inhibits DNA damage-induced apoptosis. J Biol Chem 2010; 285:12823-30. [PMID: 20124405 DOI: 10.1074/jbc.m109.094243] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
G-protein-coupled receptor kinases (GRKs) are an important family of Ser/Thr kinases that specifically phosphorylate and desensitize the activated receptor in response to environmental stimulation. Here we identify p53, a key tumor suppressor, as a novel GRK substrate in vivo, revealing a previously unknown function of GRKs in regulation of genome stability. Knockdown GRK5 in osteosarcoma cells inhibits DNA damage-induced apoptosis via a p53-mediated mechanism. Furthermore, GRK5, but not GRK2 or GRK6, phosphorylates p53 at Thr-55, which promotes the degradation of p53, leading to inhibition of p53-dependent apoptotic response to genotoxic damage. Consistently, the increase of p53 and irradiation-induced apoptosis were observed in GRK5-deficient mice. These results demonstrate GRK5 as a novel kinase of p53, as well as a negative regulator of p53-mediated signal transduction.
Collapse
Affiliation(s)
- Xiaoqing Chen
- State Key Laboratory of Medical Neurobiology and Pharmacology Research Center, Shanghai Medical College and Institutes of Brain Science, Fudan University, Shanghai 200032, China
| | | | | | | | | | | |
Collapse
|
20
|
Morris GE, Nelson CP, Standen NB, Challiss RAJ, Willets JM. Endothelin signalling in arterial smooth muscle is tightly regulated by G protein-coupled receptor kinase 2. Cardiovasc Res 2009; 85:424-33. [PMID: 19748906 PMCID: PMC2802200 DOI: 10.1093/cvr/cvp310] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
AIMS Prolonged endothelin (ET) receptor signalling causes vasoconstriction and can lead to hypertension, vascular smooth muscle hypertrophy, and hyperplasia. Usually, G protein-coupled receptor signalling is negatively regulated by G protein-coupled receptor kinases (GRKs), preventing prolonged or inappropriate signalling. This study investigated whether GRKs regulate ET receptor contractile signalling in adult Wistar rat mesenteric arterial smooth muscle cells (MSMCs). METHODS AND RESULTS ET-1-stimulated phospholipase C (PLC) activity and changes in [Ca2+]i were assessed using confocal microscopy in rat MSMCs transfected with the pleckstrin-homology domain of PLCdelta1 (eGFP-PH) and loaded with Fura-Red. ET-1 applications (30 s) stimulated transient concentration-dependent eGFP-PH translocations from plasma membrane to cytoplasm and graded [Ca2+]i increases. ET-1-mediated PLC signalling was blocked by the type A endothelin receptor (ET(A)R) antagonist, BQ123. To characterize ET(A)R desensitization, cells were stimulated with a maximally effective concentration of ET-1 (50 nM, 30 s) followed by a variable washout period and a second identical application of ET-1. This brief exposure to ET-1 markedly decreased ET(A)R responsiveness to re-challenge, and reversal was incomplete even after increasing the time period between agonist challenges to 60 min. To assess GRK involvement in ET(A)R desensitization, MSMCs were co-transfected with eGFP-PH and catalytically inactive (D110A,K220R)GRK2, (D110A,K220R)GRK3, (K215R)GRK5, or (K215R)GRK6 constructs. (D110A,K220R)GRK2 expression significantly attenuated ET(A)R desensitization, whereas other constructs were ineffective. Small interfering RNA-targeted GRK2 depletion equally attenuated ET(A)R desensitization. Finally, immunocyotchemical data showed that ET(A)R activation recruited endogenous GRK2 from cytoplasm to membrane. CONCLUSION These studies identify GRK2 as a key regulator of ET(A)R responsiveness in resistance arteries, highlighting the potential importance of this GRK isoenzyme in regulating vasoconstrictor signalling pathways implicated in vascular disease.
Collapse
Affiliation(s)
- Gavin E Morris
- Reproductive Sciences Section, Department of Cancer Studies and Molecular Medicine, Clinical Sciences Building, Leicester Royal Infirmary, Leicester LE2 7LX, UK
| | | | | | | | | |
Collapse
|
21
|
Jiang X, Benovic JL, Wedegaertner PB. Plasma membrane and nuclear localization of G protein coupled receptor kinase 6A. Mol Biol Cell 2007; 18:2960-9. [PMID: 17538017 PMCID: PMC1949383 DOI: 10.1091/mbc.e07-01-0013] [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] [Indexed: 12/19/2022] Open
Abstract
G protein-coupled receptor (GPCR) kinases (GRKs) specifically phosphorylate agonist-occupied GPCRs at the inner surface of the plasma membrane (PM), leading to receptor desensitization. Here we show that the C-terminal 30 amino acids of GRK6A contain multiple elements that either promote or inhibit PM localization. Disruption of palmitoylation by individual mutation of cysteine 561, 562, or 565 or treatment of cells with 2-bromopalmitate shifts GRK6A from the PM to both the cytoplasm and nucleus. Likewise, disruption of the hydrophobic nature of a predicted amphipathic helix by mutation of two leucines to alanines at positions 551 and 552 causes a loss of PM localization. Moreover, acidic amino acids in the C-terminus appear to negatively regulate PM localization; mutational replacement of several acidic residues with neutral or basic residues rescues PM localization of a palmitoylation-defective GRK6A. Last, we characterize the novel nuclear localization, showing that nuclear export of nonpalmitoylated GRK6A is sensitive to leptomycin B and that GRK6A contains a potential nuclear localization signal. Our results suggest that the C-terminus of GRK6A contains a novel electrostatic palmitoyl switch in which acidic residues weaken the membrane-binding strength of the amphipathic helix, thus allowing changes in palmitoylation to regulate PM versus cytoplasmic/nuclear localization.
Collapse
Affiliation(s)
- Xiaoshan Jiang
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | | | | |
Collapse
|
22
|
Yi XP, Zhou J, Huber L, Qu J, Wang X, Gerdes AM, Li F. Nuclear compartmentalization of FAK and FRNK in cardiac myocytes. Am J Physiol Heart Circ Physiol 2005; 290:H2509-15. [PMID: 16373587 DOI: 10.1152/ajpheart.00659.2005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Focal adhesion kinase (FAK) and FAK-related non-kinase (FRNK) accumulate in the nucleus of cardiac myocytes during hypertensive hypertrophy. Nuclear FAK and FRNK are phosphorylated on different serines and form distinct bright spots. The subnuclear distribution of serine-phosphorylated FAK and FRNK was examined in this study by double labeling with fibrillarin, a component of nucleoli, and Sam68, a constituent of Sam68 nuclear bodies. We also investigated the role of protein kinase C (PKC)-mediated phosphorylation of FAK and FRNK on nuclear translocation. PKC activation by 12-O-tetradecanoylphorbol 13-acetate treatment increased serine phosphorylation of FAK and FRNK. Specifically, FAK was phosphorylated on serine 722 but not serine 910. On the other hand, FRNK was phosphorylated on serine 217, the equivalent site of FAK serine 910, but not serine 30, the homologous site of FAK serine 722. Serine-phosphorylated FAK and FRNK redistributed into the nucleus and formed distinct patterns. FAK with phosphorylation on serine 722 colocalized with Sam68 but not fibrillarin. On the contrary, FRNK phosphorylated on 217 coexisted with fibrillarin but not Sam68. Immunoprecipitation also confirmed that FAK associated with Sam68 and FRNK interacted with fibrillarin, respectively. These results suggest that FAK and FRNK target different nuclear subdomains by their association with distinct nuclear proteins.
Collapse
Affiliation(s)
- Xian Ping Yi
- Cardiovascular Research Institute-South Dakota Health Research Foundation, 1100 East 21st Street, Sioux Falls, SD 57105, USA
| | | | | | | | | | | | | |
Collapse
|