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Cao S, Han C, Xuan C, Li X, Wen J, Xu D. Effects of cGMP/Akt/GSK-3β signaling pathway on atrial natriuretic peptide secretion in rabbits with rapid atrial pacing. Front Physiol 2022; 13:861981. [PMID: 36060704 PMCID: PMC9437264 DOI: 10.3389/fphys.2022.861981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 07/18/2022] [Indexed: 11/13/2022] Open
Abstract
Atrial natriuretic peptide (ANP) plays a pivotal role in the regulation of the cardiovascular system. The ANP level increases during atrial fibrillation (AF), suggesting that AF may provoke ANP secretion, but its potential mechanism is still unclear. In the present study, the potential mechanisms of rapid atrial pacing (RAP) regulating ANP secretion was explored. Rabbits were subjected to burst RAP, ANP secretion increased whereas cyclic guanosine monophosphate (cGMP) concentrations decreased during RAP. The p-Akt and p-GSK-3β levels decreased in atrial tissues. Natriuretic peptide receptor A (NPR-A) protein and particulate guanylate cyclase (PGC) activity were detected. The sensitivity of NPR-A to ANP decreased, leading to the decrease of PGC activity. Also, the isolated atrial perfusion system were made in the rabbit model, cGMP was shown to inhibit ANP secretion, and the Akt inhibitor LY294002 (LY) and GSK-3β inhibitor SB216763 (SB) attenuated the inhibitory effects of cGMP on ANP secretion and enhanced the inhibitory effects of cGMP on atrial dynamics. In conclusion, NPR-A interacts with ANP to regulate PGC expression, and influence the expression of cGMP during RAP, which involves in the Akt/GSK-3β signaling pathway. From the aforementioned points we conclude that cGMP regulates ANP secretion by the Akt/GSK-3β signaling pathway during atrial pacing.
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Affiliation(s)
- Shuxia Cao
- Center of Morphological Experiment, Medical College of Yanbian University, Jilin, China
| | - Chengyong Han
- Center of Morphological Experiment, Medical College of Yanbian University, Jilin, China
| | - Chunhua Xuan
- Department of Cardiology, Affiliated Hospital of Yanbian University, Jilin, China
| | - Xiangdan Li
- Center of Morphological Experiment, Medical College of Yanbian University, Jilin, China
| | - Jing Wen
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
- *Correspondence: Jing Wen, ; Dongyuan Xu,
| | - Dongyuan Xu
- Center of Morphological Experiment, Medical College of Yanbian University, Jilin, China
- *Correspondence: Jing Wen, ; Dongyuan Xu,
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Salazar J, Rojas-Quintero J, Cano C, Pérez JL, Ramírez P, Carrasquero R, Torres W, Espinoza C, Chacín-González M, Bermúdez V. Neprilysin: A Potential Therapeutic Target of Arterial Hypertension? Curr Cardiol Rev 2020; 16:25-35. [PMID: 31241018 PMCID: PMC7062041 DOI: 10.2174/1573403x15666190625160352] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 06/13/2019] [Accepted: 06/13/2019] [Indexed: 02/07/2023] Open
Abstract
Arterial hypertension is the most prevalent chronic disease in the adult population of developed countries and it constitutes a significant risk factor in the development of cardiovascular disease, contributing to the emergence of many comorbidities, among which heart failure excels, a clinical syndrome that nowadays represents a major health problem with uncountable hospitalizations and the indolent course of which progressively worsens until quality of life decreases and lastly death occurs prematurely. In the light of this growing menace, each day more efforts are invested in the field of cardiovascular pharmacology, searching for new therapeutic options that allow us to modulate the physiological systems that appear among these pathologies. Therefore, in the later years, the study of natriuretic peptides has become so relevant, which mediate beneficial effects at the cardiovascular level such as diuresis, natriuresis, and decreasing cardiac remodeling; their metabolism is mediated by neprilysin, a metalloproteinase, widely expressed in the human and capable of catalyzing many substrates. The modulation of these functions has been studied by decades, giving room to Sacubitril, the first neprilysin inhibitor, which in conjunction with an angiotensin receptor blocker has provided a high efficacy and tolerability among patients with heart failure, for whom it has already been approved and recommended. Nonetheless, in the matter of arterial hypertension, significant findings have arisen that demonstrate the potential role that it will play among the pharmacological alternatives in the upcoming years.
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Affiliation(s)
- Juan Salazar
- Endocrine and Metabolic Disease Research Center, School of Medicine, University of Zulia, Maracaibo, Venezuela
| | - Joselyn Rojas-Quintero
- Pulmonary and Critical Care Medicine Department, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, United States
| | - Clímaco Cano
- Endocrine and Metabolic Disease Research Center, School of Medicine, University of Zulia, Maracaibo, Venezuela
| | - José L Pérez
- Endocrine and Metabolic Disease Research Center, School of Medicine, University of Zulia, Maracaibo, Venezuela
| | - Paola Ramírez
- Endocrine and Metabolic Disease Research Center, School of Medicine, University of Zulia, Maracaibo, Venezuela
| | - Rubén Carrasquero
- Endocrine and Metabolic Disease Research Center, School of Medicine, University of Zulia, Maracaibo, Venezuela
| | - Wheeler Torres
- Endocrine and Metabolic Disease Research Center, School of Medicine, University of Zulia, Maracaibo, Venezuela
| | | | | | - Valmore Bermúdez
- Universidad Simon Bolívar, Facultad de Ciencias de la Salud, Barranquilla, Colombia
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Fu S, Ping P, Wang F, Luo L. Synthesis, secretion, function, metabolism and application of natriuretic peptides in heart failure. J Biol Eng 2018; 12:2. [PMID: 29344085 PMCID: PMC5766980 DOI: 10.1186/s13036-017-0093-0] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 12/21/2017] [Indexed: 12/11/2022] Open
Abstract
As a family of hormones with pleiotropic effects, natriuretic peptide (NP) system includes atrial NP (ANP), B-type NP (BNP), C-type NP (CNP), dendroaspis NP and urodilatin, with NP receptor-A (guanylate cyclase-A), NP receptor-B (guanylate cyclase-B) and NP receptor-C (clearance receptor). These peptides are genetically distinct, but structurally and functionally related for regulating circulatory homeostasis in vertebrates. In humans, ANP and BNP are encoded by NP precursor A (NPPA) and NPPB genes on chromosome 1, whereas CNP is encoded by NPPC on chromosome 2. NPs are synthesized and secreted through certain mechanisms by cardiomyocytes, fibroblasts, endotheliocytes, immune cells (neutrophils, T-cells and macrophages) and immature cells (embryonic stem cells, muscle satellite cells and cardiac precursor cells). They are mainly produced by cardiovascular, brain and renal tissues in response to wall stretch and other causes. NPs provide natriuresis, diuresis, vasodilation, antiproliferation, antihypertrophy, antifibrosis and other cardiometabolic protection. NPs represent body's own antihypertensive system, and provide compensatory protection to counterbalance vasoconstrictor-mitogenic-sodium retaining hormones, released by renin-angiotensin-aldosterone system (RAAS) and sympathetic nervous system (SNS). NPs play central roles in regulation of heart failure (HF), and are inactivated through not only NP receptor-C, but also neutral endopeptidase (NEP), dipeptidyl peptidase-4 and insulin degrading enzyme. Both BNP and N-terminal proBNP are useful biomarkers to not only make the diagnosis and assess the severity of HF, but also guide the therapy and predict the prognosis in patients with HF. Current NP-augmenting strategies include the synthesis of NPs or agonists to increase NP bioactivity and inhibition of NEP to reduce NP breakdown. Nesiritide has been established as an available therapy, and angiotensin receptor blocker NEP inhibitor (ARNI, LCZ696) has obtained extremely encouraging results with decreased morbidity and mortality. Novel pharmacological approaches based on NPs may promote a therapeutic shift from suppressing the RAAS and SNS to re-balancing neuroendocrine dysregulation in patients with HF. The current review discussed the synthesis, secretion, function and metabolism of NPs, and their diagnostic, therapeutic and prognostic values in HF.
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Affiliation(s)
- Shihui Fu
- Department of Geriatric Cardiology, Chinese People’s Liberation Army General Hospital, Beijing, 100853 China
- Department of Cardiology and Hainan Branch, Chinese People’s Liberation Army, General Hospital, Beijing, China
| | - Ping Ping
- Department of Pharmaceutical Care, Chinese People’s, Liberation Army General Hospital, Beijing, China
| | - Fengqi Wang
- Department of Cardiology and Hainan Branch, Chinese People’s Liberation Army, General Hospital, Beijing, China
| | - Leiming Luo
- Department of Geriatric Cardiology, Chinese People’s Liberation Army General Hospital, Beijing, 100853 China
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Shi Z, Fu F, Yu L, Xing W, Su F, Liang X, Tie R, Ji L, Zhu M, Yu J, Zhang H. Vasonatrin peptide attenuates myocardial ischemia-reperfusion injury in diabetic rats and underlying mechanisms. Am J Physiol Heart Circ Physiol 2014; 308:H281-90. [PMID: 25485902 DOI: 10.1152/ajpheart.00666.2014] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Diabetes mellitus increases morbidity/mortality of ischemic heart disease. Although atrial natriuretic peptide and C-type natriuretic peptide reduce the myocardial ischemia-reperfusion damage in nondiabetic rats, whether vasonatrin peptide (VNP), the artificial synthetic chimera of atrial natriuretic peptide and C-type natriuretic peptide, confers cardioprotective effects against ischemia-reperfusion injury, especially in diabetic patients, is still unclear. This study was designed to investigate the effects of VNP on ischemia-reperfusion injury in diabetic rats and to further elucidate its mechanisms. The high-fat diet-fed streptozotocin-induced diabetic Sprague-Dawley rats were subjected to ischemia-reperfusion operation. VNP treatment (100 μg/kg iv, 10 min before reperfusion) significantly improved the instantaneous first derivation of left ventricle pressure (±LV dP/dtmax) and LV systolic pressure and reduced LV end-diastolic pressure, apoptosis index, caspase-3 activity, plasma creatine kinase (CK), and lactate dehydrogenase (LDH) activities. Moreover, VNP inhibited endoplasmic reticulum (ER) stress by suppressing glucose-regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP). These effects were mimicked by 8-bromine-cyclic guanosinemonophosphate (8-Br-cGMP), a cGMP analog, whereas they were inhibited by KT-5823, the selective inhibitor of PKG. In addition, pretreatment with tauroursodeoxycholic acid (TUDCA), a specific inhibitor of ER stress, could not further promote the VNP's cardioprotective effect in diabetic rats. In vitro H9c2 cardiomyocytes were subjected to hypoxia/reoxygenation and incubated with or without VNP (10(-8) mol/l). Gene knockdown of PKG1α with siRNA blunted VNP inhibition of ER stress and apoptosis, while overexpression of PKG1α resulted in significant decreased ER stress and apoptosis. VNP protects the diabetic heart against ischemia-reperfusion injury by inhibiting ER stress via the cGMP-PKG signaling pathway. These results suggest that VNP may have potential therapeutic value for the diabetic patients with ischemic heart disease.
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Affiliation(s)
- Zhenwei Shi
- Experiment Teaching Center, Fourth Military Medical University, Xi'an, China
| | - Feng Fu
- Department of Physiology, Fourth Military Medical University, Xi'an, China
| | - Liming Yu
- Experiment Teaching Center, Fourth Military Medical University, Xi'an, China
| | - Wenjuan Xing
- Department of Physiology, Fourth Military Medical University, Xi'an, China
| | - Feifei Su
- Department of Cardiology, Tangdu Hospital, Fourth Military Medical University, Xi'an, China; and
| | - Xiangyan Liang
- Experiment Teaching Center, Fourth Military Medical University, Xi'an, China
| | - Ru Tie
- Experiment Teaching Center, Fourth Military Medical University, Xi'an, China
| | - Lele Ji
- Experiment Teaching Center, Fourth Military Medical University, Xi'an, China
| | - Miaozhang Zhu
- Department of Physiology, Fourth Military Medical University, Xi'an, China
| | - Jun Yu
- Experimental Center, The Second Affiliated Hospital, School of Medicine, Xi'an Medical University, Xi'an, China
| | - Haifeng Zhang
- Experiment Teaching Center, Fourth Military Medical University, Xi'an, China;
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Pandey KN. Guanylyl cyclase/natriuretic peptide receptor-A signaling antagonizes phosphoinositide hydrolysis, Ca(2+) release, and activation of protein kinase C. Front Mol Neurosci 2014; 7:75. [PMID: 25202235 PMCID: PMC4141235 DOI: 10.3389/fnmol.2014.00075] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 08/05/2014] [Indexed: 11/25/2022] Open
Abstract
Thus far, three related natriuretic peptides (NPs) and three distinct sub-types of cognate NP receptors have been identified and characterized based on the specific ligand binding affinities, guanylyl cyclase activity, and generation of intracellular cGMP. Atrial and brain natriuretic peptides (ANP and BNP) specifically bind and activate guanylyl cyclase/natriuretic peptide receptor-A (GC-A/NPRA), and C-type natriuretic peptide (CNP) shows specificity to activate guanylyl cyclase/natriuretic peptide receptor-B (GC-B/NPRB). All three NPs bind to natriuretic peptide receptor-C (NPRC), which is also known as clearance or silent receptor. The NPRA is considered the principal biologically active receptor of NP family; however, the molecular signaling mechanisms of NP receptors are not well understood. The activation of NPRA and NPRB produces the intracellular second messenger cGMP, which serves as the major signaling molecule of all three NPs. The activation of NPRB in response to CNP also produces the intracellular cGMP; however, at lower magnitude than that of NPRA, which is activated by ANP and BNP. In addition to enhanced accumulation of intracellular cGMP in response to all three NPs, the levels of cAMP, Ca2+ and inositol triphosphate (IP3) have also been reported to be altered in different cells and tissue types. Interestingly, ANP has been found to lower the concentrations of cAMP, Ca2+, and IP3; however, NPRC has been proposed to increase the levels of these metabolic signaling molecules. The mechanistic studies of decreased and/or increased levels of cAMP, Ca2+, and IP3 in response to NPs and their receptors have not yet been clearly established. This review focuses on the signaling mechanisms of ANP/NPRA and their biological effects involving an increased level of intracellular accumulation of cGMP and a decreased level of cAMP, Ca2+, and IP3 in different cells and tissue systems.
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Affiliation(s)
- Kailash N Pandey
- Department of Physiology, School of Medicine, Tulane University Health Sciences Center New Orleans, LA, USA
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Abstract
Background Recombinant human brain natriuretic peptide (rhBNP) is an important peptide-based therapeutic drug indicated for the treatment of acute heart failure. Accurate determination of the potency of therapeutic rhBNP is crucial for the safety and efficacy of the drug. The current bioassay involves use of rabbit aortic strips, with experiments being complicated and time-consuming and markedly variable in results. Animal-less methods with better precision and accuracy should be explored. We have therefore developed an alternative cell-based assay, which relies on the ability of BNP to induce cGMP production in HEK293 cells expressing BNP receptor guanylyl cyclase-A. Methodology/Principal Findings An alternative assay based on the measurement of BNP-induced cGMP production was developed. Specifically, the bioassay employs cells engineered to express BNP receptor guanylyl cyclase-A (GCA). Upon rhBNP stimulation, the levels of the second messager cGMP in these cells drastically increased and subsequently secreted into culture supernatants. The quantity of cGMP, which corresponds to the rhBNP activity, was determined using a competitive ELISA developed by us. Compared with the traditional assay, the novel cell-based assay demonstrated better reproducibility and precision. Conclusion/Significance The optimized cell-based assay is much simpler, more rapid and precise compared with the traditional assay using animal tissues. To our knowledge, this is the first report on a novel and viable alternative assay for rhBNP potency analysis.
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Duda T, Pertzev A, Sharma RK. Ca(2+) modulation of ANF-RGC: new signaling paradigm interlocked with blood pressure regulation. Biochemistry 2012; 51:9394-405. [PMID: 23088492 DOI: 10.1021/bi301176c] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
ANF-RGC is the prototype receptor membrane guanylate cyclase that is both the receptor and the signal transducer of the most hypotensive hormones, ANF and BNP. It is a single-transmembrane protein. After binding these hormones at the extracellular domain, ANF-RGC at its intracellular domain signals the activation of the C-terminal catalytic module and accelerates the production of the second messenger, cyclic GMP, which controls blood pressure, cardiac vasculature, and fluid secretion. At present, this is the sole transduction mechanism and the physiological function of ANF-RGC. Through comprehensive studies involving biochemistry, immunohistochemistry, and blood pressure measurements in mice with targeted gene deletions, this study demonstrates a new signaling model of ANF-RGC that also controls blood pressure. In this model, (1) ANF-RGC is not the transducer of ANF and BNP, (2) its extracellular domain is not used for signaling, and (3) the signal flow is not downstream from the extracellular domain to the core catalytic domain. Instead, the signal is the intracellular Ca(2+), which is translated at the site of its reception, at the core catalytic domain of ANF-RGC. A model for this Ca(2+) signal transduction is diagrammed. It captures Ca(2+) through its Ca(2+) sensor myristoylated neurocalcin δ and upregulates ANF-RGC activity with a K(1/2) of 0.5 μM. The neurocalcin δ-modulated domain resides in the (849)DIVGFTALSAESTPMQVV(866) segment of ANF-RGC, which is a part of the core catalytic domain. Thereby, ANF-RGC is primed to receive, transmit, and translate the Ca(2+) signals into the generation of cyclic GMP at a rapid rate. The study defines a new paradigm of membrane guanylate cyclase signaling, which is linked to the physiology of cardiac vasculature regulation and possibly also to fluid secretion.
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Affiliation(s)
- Teresa Duda
- Research Divisions of Biochemistry and Molecular Biology, The Unit of Regulatory and Molecular Biology, Salus University, Elkins Park, Pennsylvania 19027, United States.
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Chen BY, Chen JK, Zhu MZ, Zhang DL, Sun JS, Pei JM, Feng HS, Zhu XX, Jin J, Yu J. AC-NP: a novel chimeric peptide with natriuretic and vasorelaxing actions. PLoS One 2011; 6:e20477. [PMID: 21647224 PMCID: PMC3101257 DOI: 10.1371/journal.pone.0020477] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Accepted: 04/27/2011] [Indexed: 12/11/2022] Open
Abstract
The aim of this study was to evaluate the cardiovascular and renal activities of a newly designed natriuretic peptide (NP). Here, we engineered a novel 28-amino acid chimeric peptide, termed AC-NP that combined the 17-amino acid ring of C type natriuretic peptide (CNP) with the 6-amino acid N-terminus and 5-amino acid C-terminus of atrial natriuretic peptide (ANP). Both in vitro and in vivo experiments were performed to determine the actions of AC-NP. In normal rats, AC-NP proved to be more potentially diuretic, natriuretic and hypotensive compared with other NPs, such as ANP, CNP and vasonatrin peptide (VNP), which is another man-made NP. In relaxation of isolated abdominal aorta from rat, AC-NP was equally effective to ANP, CNP and VNP. Elevated levels of 3',5'-guanosine monophosphate (cGMP) in plasma and urine cGMP excretion indicated the participation of cGMP in the functions of AC-NP. Taken together, innovative designed AD-NP might be a new candidate therapeutic peptide against cardiorenal disorders.
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Affiliation(s)
- Bao-Ying Chen
- Department of Radiology, Tangdu Hospital, Fourth Military Medical University, Xi'an, China
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Duda T, Yadav P, Sharma RK. Allosteric modification, the primary ATP activation mechanism of atrial natriuretic factor receptor guanylate cyclase. Biochemistry 2011; 50:1213-25. [PMID: 21222471 DOI: 10.1021/bi1018978] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
ANF-RGC is the prototype receptor membrane guanylate cyclase being both the receptor and the signal transducer of the most hypotensive hormones, ANF and BNP. It is a single transmembrane-spanning protein. After binding these hormones at the extracellular domain it at its intracellular domain signals activation of the C-terminal catalytic module and accelerates the production of its second messenger, cyclic GMP, which controls blood pressure, cardiac vasculature, and fluid secretion. ATP is obligatory for the posttransmembrane dynamic events leading to ANF-RGC activation. It functions through the ATP-regulated module, ARM (KHD) domain, of ANF-RGC. In the current over a decade held model "phosphorylation of the KHD is absolutely required for hormone-dependent activation of NPR-A" [Potter, L. R., and Hunter, T. (1998) Mol. Cell. Biol. 18, 2164-2172]. The presented study challenges this concept. It demonstrates that, instead, ATP allosteric modification of ARM is the primary signaling step of ANF-GC activation. In this two-step new dynamic model, ATP in the first step binds ARM. This triggers in it a chain of transduction events, which cause its allosteric modification. The modification partially activates (about 50%) ANF-RGC and, concomitantly, also prepares the ARM for the second successive step. In this second step, ARM is phosphorylated and ANF-RGC achieves additional (∼50%) full catalytic activation. The study defines a new paradigm of the ANF-RGC signaling mechanism.
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Affiliation(s)
- Teresa Duda
- Research Division of Biochemistry, The Unit of Regulatory and Molecular Biology, Salus University, 8360 Old York Road, Elkins Park, Pennsylvania 19027, United States.
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Duda T, Yadav P, Sharma RK. ATP allosteric activation of atrial natriuretic factor receptor guanylate cyclase. FEBS J 2010; 277:2550-3. [PMID: 20553491 DOI: 10.1111/j.1742-4658.2010.07670.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Atrial natriuretic factor receptor guanylate cyclase (ANF-RGC) is the receptor and the signal transducer of two natriuretic peptide hormones: atrial natriuretic factor and brain natriuretic peptide. It is a single transmembrane-spanning protein. It binds these hormones at its extracellular domain and activates its intracellular catalytic domain. This results in the accelerated production of cyclic GMP, a second messenger in controlling blood pressure, cardiac vasculature and fluid secretion. ATP is obligatory for the transduction of this hormonal signal. Two models of ATP action have been proposed. In Model 1, it is a direct allosteric transducer. It binds to the defined regulatory domain (ATP-regulated module) juxtaposed to the C-terminal side of the transmembrane domain of ANF-RGC, induces a cascade of temporal and spatial changes and activates the catalytic module residing at the C-terminus of the cyclase. In Model 2, before ATP can exhibit its allosteric effect, ANF-RGC must first be phosphorylated by an as yet unidentified protein kinase. This initial step is obligatory in atrial natriuretic factor signaling of ANF-RGC. Until now, none of these models has been directly validated because it has not been possible to segregate the allosteric and the phosphorylation effects of ATP in ANF-RGC activation. The present study accomplishes this aim through a novel probe, staurosporine. This unequivocally validates Model 1 and settles the over two-decade long debate on the role of ATP in ANF-RGC signaling. In addition, the present study demonstrates that the mechanisms of allosteric modification of ANF-RGC by staurosporine and adenylyl-imidodiphosphate, a nonhydrolyzable analog of ATP, are almost (or totally) identical.
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Affiliation(s)
- Teresa Duda
- Research Divisions of Biochemistry and Molecular Biology, Salus University, Elkins Park, PA 19027, USA.
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