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Soni UK, Jenny L, Hegde RS. IGF-1R targeting in cancer - does sub-cellular localization matter? J Exp Clin Cancer Res 2023; 42:273. [PMID: 37858153 PMCID: PMC10588251 DOI: 10.1186/s13046-023-02850-7] [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: 09/09/2023] [Accepted: 10/03/2023] [Indexed: 10/21/2023] Open
Abstract
The insulin-like growth factor receptor (IGF-1R) was among the most intensively pursued kinase targets in oncology. However, even after a slew of small-molecule and antibody therapeutics reached clinical trials for a range of solid tumors, the initial promise remains unfulfilled. Mechanisms of resistance to, and toxicities resulting from, IGF-1R-targeted drugs are well-catalogued, and there is general appreciation of the fact that a lack of biomarker-based patient stratification was a limitation of previous clinical trials. But no next-generation therapeutic strategies have yet successfully exploited this understanding in the clinic.Currently there is emerging interest in re-visiting IGF-1R targeted therapeutics in combination-treatment protocols with predictive biomarker-driven patient-stratification. One such biomarker that emerged from early clinical trials is the sub-cellular localization of IGF-1R. After providing some background on IGF-1R, its drugging history, and the trials that led to the termination of drug development for this target, we look more deeply into the correlation between sub-cellular localization of IGF-1R and susceptibility to various classes of IGF-1R - targeted agents.
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Affiliation(s)
- Upendra K Soni
- Division of Developmental Biology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Liam Jenny
- Division of Developmental Biology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Rashmi S Hegde
- Division of Developmental Biology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
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2
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Girnita L, Smith TJ, Janssen JAMJL. It Takes Two to Tango: IGF-I and TSH Receptors in Thyroid Eye Disease. J Clin Endocrinol Metab 2022; 107:S1-S12. [PMID: 35167695 PMCID: PMC9359450 DOI: 10.1210/clinem/dgac045] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Indexed: 12/13/2022]
Abstract
CONTEXT Thyroid eye disease (TED) is a complex autoimmune disease process. Orbital fibroblasts represent the central orbital immune target. Involvement of the TSH receptor (TSHR) in TED is not fully understood. IGF-I receptor (IGF-IR) is overexpressed in several cell types in TED, including fibrocytes and orbital fibroblasts. IGF-IR may form a physical and functional complex with TSHR. OBJECTIVE Review literature relevant to autoantibody generation in TED and whether these induce orbital fibroblast responses directly through TSHR, IGF-IR, or both. EVIDENCE IGF-IR has traditionally been considered a typical tyrosine kinase receptor in which tyrosine residues become phosphorylated following IGF-I binding. Evidence has emerged that IGF-IR possesses kinase-independent activities and can be considered a functional receptor tyrosine kinase/G-protein-coupled receptor hybrid, using the G-protein receptor kinase/β-arrestin system. Teprotumumab, a monoclonal IGF-IR antibody, effectively reduces TED disease activity, proptosis, and diplopia. In addition, the drug attenuates in vitro actions of both IGF-I and TSH in fibrocytes and orbital fibroblasts, including induction of proinflammatory cytokines by TSH and TED IgGs. CONCLUSIONS Although teprotumumab has been proven effective and relatively safe in the treatment of TED, many questions remain pertaining to IGF-IR, its relationship with TSHR, and how the drug might be disrupting these receptor protein/protein interactions. Here, we propose 4 possible IGF-IR activation models that could underlie clinical responses to teprotumumab observed in patients with TED. Teprotumumab is associated with several adverse events, including hyperglycemia and hearing abnormalities. Underpinning mechanisms of these are being investigated. Patients undergoing treatment with drug must be monitored for these and managed with best medical practices.
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Affiliation(s)
- Leonard Girnita
- Department of Oncology and Pathology, BioClinicum, Karolinska Institutet and Karolinska University Hospital, 17164 Stockholm, Sweden
| | - Terry J Smith
- Kellogg Eye Center, Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, MI 48105, USA
- Division of Metabolism, Endocrinology, and Diabetes, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48105, USA
| | - Joseph A M J L Janssen
- Erasmus Medical Center, Department of Internal Medicine, Division of Endocrinology, Dr. Molewaterplein 40, 3015 GD Rotterdam, The Netherlands
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3
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Wang P, Mak VCY, Cheung LWT. Drugging IGF-1R in cancer: New insights and emerging opportunities. Genes Dis 2022; 10:199-211. [PMID: 37013053 PMCID: PMC10066341 DOI: 10.1016/j.gendis.2022.03.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 03/02/2022] [Indexed: 11/19/2022] Open
Abstract
The insulin-like growth factor (IGF) axis plays important roles in cancer development and metastasis. The type 1 IGF receptor (IGF-1R) is a key member in the IGF axis and has long been recognized for its oncogenic role in multiple cancer lineages. Here we review the occurrence of IGF-1R aberrations and activation mechanisms in cancers, which justify the development of anti-IGF-1R therapies. We describe the therapeutic agents available for IGF-1R inhibition, with focuses on the recent or ongoing pre-clinical and clinical studies. These include antisense oligonucleotide, tyrosine kinase inhibitors and monoclonal antibodies which may be conjugated with cytotoxic drug. Remarkably, simultaneous targeting of IGF-1R and several other oncogenic vulnerabilities has shown early promise, highlighting the potential benefits of combination therapy. Further, we discuss the challenges in targeting IGF-1R so far and new concepts to improve therapeutic efficacy such as blockage of the nuclear translocation of IGF-1R.
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Saito M, Otsu W. [Mechanisms of cell proliferation through primary cilium]. Nihon Yakurigaku Zasshi 2019; 154:197-202. [PMID: 31597899 DOI: 10.1254/fpj.154.197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Primary cilium is a membrane-protruding sensory organelle, which is organized from a basal body in G0/G1 phase cells. The resorption of primary cilia under specific growth factor stimuli is coupled to cell cycle re-entry and cell proliferation, and the proliferative function is vital for the organization of organs at an embryonic stage. In fact, abnormalities in ciliogenesis and/or cilium-derived signaling lead to malformation of various organs, such as the brain, eyes, nose, ear, heart, lung, liver, kidney, and bones. The inborn genetic disorders are collectively called 〝ciliopathy〟. However, the pathogenesis of the ciliopathies has largely remained unexplained, especially little is known about the cellular machinery that controls the ciliary resorption. Tctex-1 (t-complex testis expressed-1), one of the light chains of cytoplasmic dynein complex, regulates intracellular trafficking along microtubule. Tctex-1 phosphorylated at Thr94 is, in turn, free from the dynein complex to execute dynein-free functions. This review summarizes the current situation of the mechanisms of ciliary resorption with a central focus on the role of phosphorylated Tctex-1.
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Affiliation(s)
- Masaki Saito
- Department of Molecular Pharmacology, Tohoku University School of Medicine
| | - Wataru Otsu
- Department of Ophthalmology, Margaret M. Dyson Vision Research Institute, Weill Medical College of Cornell University.,Department of Biomedical Research, Gifu Pharmaceutical University
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5
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Abstract
Non-communicable diseases, such as cardiovascular diseases, are the leading cause of mortality worldwide. For this reason, a tremendous effort is being made worldwide to effectively circumvent these afflictions, where insulin-like growth factor 1 (IGF1) is being proposed both as a marker and as a central cornerstone in these diseases, making it an interesting molecule to focus on. Firstly, at the initiation of metabolic deregulation by overfeeding, IGF1 is decreased/inhibited. Secondly, such deficiency seems to be intimately related to the onset of MetS and establishment of vascular derangements leading to atherosclerosis and finally playing a definitive part in cerebrovascular and myocardial accidents, where IGF1 deficiency seems to render these organs vulnerable to oxidative and apoptotic/necrotic damage. Several human cohort correlations together with basic/translational experimental data seem to confirm deep IGF1 implication, albeit with controversy, which might, in part, be given by experimental design leading to blurred result interpretation.
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Nishimura Y, Kasahara K, Shiromizu T, Watanabe M, Inagaki M. Primary Cilia as Signaling Hubs in Health and Disease. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2019; 6:1801138. [PMID: 30643718 PMCID: PMC6325590 DOI: 10.1002/advs.201801138] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 09/20/2018] [Indexed: 05/13/2023]
Abstract
Primary cilia detect extracellular cues and transduce these signals into cells to regulate proliferation, migration, and differentiation. Here, the function of primary cilia as signaling hubs of growth factors and morphogens is in focus. First, the molecular mechanisms regulating the assembly and disassembly of primary cilia are described. Then, the role of primary cilia in mediating growth factor and morphogen signaling to maintain human health and the potential mechanisms by which defects in these pathways contribute to human diseases, such as ciliopathy, obesity, and cancer are described. Furthermore, a novel signaling pathway by which certain growth factors stimulate cell proliferation through suppression of ciliogenesis is also described, suggesting novel therapeutic targets in cancer.
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Affiliation(s)
- Yuhei Nishimura
- Department of Integrative PharmacologyMie University Graduate School of MedicineTsuMie514‐8507Japan
| | - Kousuke Kasahara
- Department of PhysiologyMie University Graduate School of MedicineTsuMie514‐8507Japan
| | - Takashi Shiromizu
- Department of Integrative PharmacologyMie University Graduate School of MedicineTsuMie514‐8507Japan
| | - Masatoshi Watanabe
- Department of Oncologic PathologyMie University Graduate School of MedicineTsuMie514‐8507Japan
| | - Masaki Inagaki
- Department of PhysiologyMie University Graduate School of MedicineTsuMie514‐8507Japan
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Blurring Boundaries: Receptor Tyrosine Kinases as functional G Protein-Coupled Receptors. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 339:1-40. [DOI: 10.1016/bs.ircmb.2018.02.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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8
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Partial IGF-1 deficiency is sufficient to reduce heart contractibility, angiotensin II sensibility, and alter gene expression of structural and functional cardiac proteins. PLoS One 2017; 12:e0181760. [PMID: 28806738 PMCID: PMC5555709 DOI: 10.1371/journal.pone.0181760] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 07/06/2017] [Indexed: 01/15/2023] Open
Abstract
Circulating levels of IGF-1 may decrease under several circumstances like ageing, metabolic syndrome, and advanced cirrhosis. This reduction is associated with insulin resistance, dyslipidemia, progression to type 2 diabetes, and increased risk for cardiovascular diseases. However, underlying mechanisms between IGF-1 deficiency and cardiovascular disease remain elusive. The specific aim of the present work was to study whether the partial IGF-1 deficiency influences heart and/or coronary circulation, comparing vasoactive factors before and after of ischemia-reperfusion (I/R). In addition, histology of the heart was performed together with cardiac gene expression for proteins involved in structure and function (extracellular matrix, contractile proteins, active peptides); carried out using microarrays, followed by RT-qPCR confirmation of the three experimental groups. IGF-1 partial deficiency is associated to a reduction in contractility and angiotensin II sensitivity, interstitial fibrosis as well as altered expression pattern of genes involved in extracellular matrix proteins, calcium dynamics, and cardiac structure and function. Although this work is descriptive, it provides a clear insight of the impact that partial IGF-1 deficiency on the heart and establishes this experimental model as suitable for studying cardiac disease mechanisms and exploring therapeutic options for patients under IGF-1 deficiency conditions.
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9
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Functional antagonism of β-arrestin isoforms balance IGF-1R expression and signalling with distinct cancer-related biological outcomes. Oncogene 2017; 36:5734-5744. [PMID: 28581517 PMCID: PMC5658667 DOI: 10.1038/onc.2017.179] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 04/09/2017] [Accepted: 05/01/2017] [Indexed: 12/21/2022]
Abstract
With very similar 3D structures, the widely expressed β-arrestin isoforms 1 and 2 play at times identical, distinct or even opposing roles in regulating various aspects of G protein-coupled receptors (GPCR) expression and signalling. Recent evidence recognizes the β-arrestin system as a key regulator of not only GPCRs, but also receptor tyrosine kinases, including the highly cancer relevant insulin-like growth factor type 1 receptor (IGF-1R). Binding of β-arrestin1 to IGF-1R leads to ligand-dependent degradation of the receptor and generates additional MAPK/ERK signalling, protecting cancer cells against anti-IGF-1R therapy. Because the interplay between β-arrestin isoforms governs the biological effects for most GPCRs, as yet unexplored for the IGF-1R, we sought to investigate specifically the regulatory roles of the β-arrestin2 isoform on expression and function of the IGF-1R. Results from controlled expression of either β-arrestin isoform demonstrate that β-arrestin2 acts in an opposite manner to β-arrestin1 by promoting degradation of an unstimulated IGF-1R, but protecting the receptor against agonist-induced degradation. Although both isoforms co-immunoprecipitate with IGF-1R, the ligand-occupied receptor has greater affinity for β-arrestin1; this association lasts longer, sustains MAPK/ERK signalling and mitigates p53 activation. Conversely, β-arrestin2 has greater affinity for the ligand-unoccupied receptor; this interaction is transient, triggers receptor ubiquitination and degradation without signalling activation, and leads to a lack of responsiveness to IGF-1, cell cycle arrest and decreased viability of cancer cells. This study reveals contrasting abilities of IGF-1R to interact with each β-arrestin isoform, depending on the presence of the ligand and demonstrates the antagonism between the two β-arrestin isoforms in controlling IGF-1R expression and function, which could be developed into a practical anti-IGF-1R strategy for cancer therapy.
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10
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Novel players in cardioprotection: Insulin like growth factor-1, angiotensin-(1–7) and angiotensin-(1–9). Pharmacol Res 2015; 101:41-55. [DOI: 10.1016/j.phrs.2015.06.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 06/27/2015] [Accepted: 06/28/2015] [Indexed: 12/14/2022]
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11
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Crudden C, Ilic M, Suleymanova N, Worrall C, Girnita A, Girnita L. The dichotomy of the Insulin-like growth factor 1 receptor: RTK and GPCR: friend or foe for cancer treatment? Growth Horm IGF Res 2015; 25:2-12. [PMID: 25466906 DOI: 10.1016/j.ghir.2014.10.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 10/06/2014] [Accepted: 10/20/2014] [Indexed: 01/14/2023]
Abstract
The prime position of the insulin-like growth factor 1 receptor (IGF-1R), at the head of the principle mitogenic and anti-apoptotic signalling cascades, along with the resilience to transformation of IGF-1R deficient cells fuelled great excitement for its anti-cancer targeting. Yet its potential has not been fulfilled, as clinical trial results fell far short of expectations. Advancements in understanding of other receptors' function have now begun to shed light on this incongruity, with the now apparent parallels highlighting the immaturity of our understanding of IGF-1R biology, with the model used for drug development now recognised as having been too simplistic. Gathering together the many advancements of the field of IGF-1R research over the past decade, alongside those in the GPCR field, advocates for a major paradigm shift in our appreciation of the subtle workings of this receptor. This review will emphasise the updating of the IGF-1R's classification from an RTK, to an RTK/GPCR functional hybrid, which integrates both canonical kinase signalling with many functions characteristic of a GPCR. Recognition of the shortcomings of IGF-1R inhibitor drug development programs and the models used not only allows us to reignite the initial interest in the IGF-1R as an anti-cancer therapeutic target, but also points to the possibility of biased ligand therapeutics, which together may hold a very powerful key to unlocking the true potential of IGF-1R modulation.
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Affiliation(s)
- Caitrin Crudden
- Department of Oncology and Pathology, Cancer Center Karolinska, Karolinska Institutet and Karolinska University Hospital, 17176 Stockholm, Sweden
| | - Marina Ilic
- Department of Oncology and Pathology, Cancer Center Karolinska, Karolinska Institutet and Karolinska University Hospital, 17176 Stockholm, Sweden
| | - Naida Suleymanova
- Department of Oncology and Pathology, Cancer Center Karolinska, Karolinska Institutet and Karolinska University Hospital, 17176 Stockholm, Sweden
| | - Claire Worrall
- Department of Oncology and Pathology, Cancer Center Karolinska, Karolinska Institutet and Karolinska University Hospital, 17176 Stockholm, Sweden
| | - Ada Girnita
- Department of Oncology and Pathology, Cancer Center Karolinska, Karolinska Institutet and Karolinska University Hospital, 17176 Stockholm, Sweden; Dermatology Department, Karolinska University Hospital, Stockholm, Sweden
| | - Leonard Girnita
- Department of Oncology and Pathology, Cancer Center Karolinska, Karolinska Institutet and Karolinska University Hospital, 17176 Stockholm, Sweden.
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12
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The small-molecule BGP-15 protects against heart failure and atrial fibrillation in mice. Nat Commun 2014; 5:5705. [DOI: 10.1038/ncomms6705] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 10/30/2014] [Indexed: 12/20/2022] Open
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13
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Zhang Y, Qin W, Qian Z, Liu X, Wang H, Gong S, Sun YG, Snutch TP, Jiang X, Tao J. Peripheral pain is enhanced by insulin-like growth factor 1 through a G protein-mediated stimulation of T-type calcium channels. Sci Signal 2014; 7:ra94. [DOI: 10.1126/scisignal.2005283] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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14
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Troncoso R, Ibarra C, Vicencio JM, Jaimovich E, Lavandero S. New insights into IGF-1 signaling in the heart. Trends Endocrinol Metab 2014; 25:128-37. [PMID: 24380833 DOI: 10.1016/j.tem.2013.12.002] [Citation(s) in RCA: 165] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 11/16/2013] [Accepted: 12/02/2013] [Indexed: 01/15/2023]
Abstract
Insulin-like growth factor 1 (IGF-1) signaling regulates contractility, metabolism, hypertrophy, autophagy, senescence, and apoptosis in the heart. IGF-1 deficiency is associated with an increased risk of cardiovascular disease, whereas cardiac activation of IGF-1 receptor (IGF-1R) protects from the detrimental effects of a high-fat diet and myocardial infarction. IGF-1R activates multiple pathways through its intrinsic tyrosine kinase activity and through coupling to heterotrimeric G protein. These pathways involve classic second messengers, phosphorylation cascades, lipid signaling, Ca(2+) transients, and gene expression. In addition, IGF-1R triggers signaling in different subcellular locations including the plasma membrane, perinuclear T tubules, and also in internalized vesicles. In this review, we provide a fresh and updated view of the complex IGF-1 scenario in the heart, including a critical focus on therapeutic strategies.
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Affiliation(s)
- Rodrigo Troncoso
- Facultad de Ciencias Quimicas y Farmaceuticas & Facultad Medicina, Universidad de Chile, Santiago 838049, Chile; Centro de Estudios Moleculares de la Célula, Facultad de Ciencias Quimicas y Farmaceuticas & Facultad de Medicina, Universidad de Chile, Santiago 838049, Chile
| | - Cristián Ibarra
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm 17177, Sweden
| | | | - Enrique Jaimovich
- Centro de Estudios Moleculares de la Célula, Facultad de Ciencias Quimicas y Farmaceuticas & Facultad de Medicina, Universidad de Chile, Santiago 838049, Chile
| | - Sergio Lavandero
- Facultad de Ciencias Quimicas y Farmaceuticas & Facultad Medicina, Universidad de Chile, Santiago 838049, Chile; Centro de Estudios Moleculares de la Célula, Facultad de Ciencias Quimicas y Farmaceuticas & Facultad de Medicina, Universidad de Chile, Santiago 838049, Chile; Department of Internal Medicine (Cardiology Division), University of Texas Southwestern Medical Center, Dallas, TX, 75390-8573, USA.
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15
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Carrasco L, Cea P, Rocco P, Peña-Oyarzún D, Rivera-Mejias P, Sotomayor-Flores C, Quiroga C, Criollo A, Ibarra C, Chiong M, Lavandero S. Role of Heterotrimeric G Protein and Calcium in Cardiomyocyte Hypertrophy Induced by IGF-1. J Cell Biochem 2014; 115:712-20. [DOI: 10.1002/jcb.24712] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 11/05/2013] [Indexed: 01/09/2023]
Affiliation(s)
- Loreto Carrasco
- Advanced Center for Chronic Diseases; Universidad de Chile; Santiago Chile
- Centro Estudios Moleculares de la Celula; Facultad de Ciencias y Farmacéuticas; Universidad de Chile; Santiago Chile
| | - Paola Cea
- Advanced Center for Chronic Diseases; Universidad de Chile; Santiago Chile
- Centro Estudios Moleculares de la Celula; Facultad de Ciencias y Farmacéuticas; Universidad de Chile; Santiago Chile
| | - Paola Rocco
- Centro Estudios Moleculares de la Celula; Facultad de Ciencias y Farmacéuticas; Universidad de Chile; Santiago Chile
| | - Daniel Peña-Oyarzún
- Advanced Center for Chronic Diseases; Universidad de Chile; Santiago Chile
- Centro Estudios Moleculares de la Celula; Facultad de Ciencias y Farmacéuticas; Universidad de Chile; Santiago Chile
| | - Pablo Rivera-Mejias
- Advanced Center for Chronic Diseases; Universidad de Chile; Santiago Chile
- Centro Estudios Moleculares de la Celula; Facultad de Ciencias y Farmacéuticas; Universidad de Chile; Santiago Chile
| | - Cristian Sotomayor-Flores
- Advanced Center for Chronic Diseases; Universidad de Chile; Santiago Chile
- Centro Estudios Moleculares de la Celula; Facultad de Ciencias y Farmacéuticas; Universidad de Chile; Santiago Chile
| | - Clara Quiroga
- Advanced Center for Chronic Diseases; Universidad de Chile; Santiago Chile
- Centro Estudios Moleculares de la Celula; Facultad de Ciencias y Farmacéuticas; Universidad de Chile; Santiago Chile
| | - Alfredo Criollo
- Advanced Center for Chronic Diseases; Universidad de Chile; Santiago Chile
- Departamento Ciencias Básicas y Comunitarias; Facultad Odontología; Universidad de Chile; Santiago Chile
| | - Cristian Ibarra
- Advanced Center for Chronic Diseases; Universidad de Chile; Santiago Chile
- Department of Medical Biochemistry and Biophysics; Karolinska Institutet; Stockholm Sweden
| | - Mario Chiong
- Advanced Center for Chronic Diseases; Universidad de Chile; Santiago Chile
- Centro Estudios Moleculares de la Celula; Facultad de Ciencias y Farmacéuticas; Universidad de Chile; Santiago Chile
| | - Sergio Lavandero
- Advanced Center for Chronic Diseases; Universidad de Chile; Santiago Chile
- Centro Estudios Moleculares de la Celula; Facultad de Ciencias y Farmacéuticas; Universidad de Chile; Santiago Chile
- Instituto de Ciencias Biomédicas; Facultad Medicina; Universidad de Chile; Santiago Chile
- Cardiology Division; Department of Internal Medicine; University of Texas Southwestern Medical Center; Dallas Texas
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Something old, something new and something borrowed: emerging paradigm of insulin-like growth factor type 1 receptor (IGF-1R) signaling regulation. Cell Mol Life Sci 2013; 71:2403-27. [PMID: 24276851 PMCID: PMC4055838 DOI: 10.1007/s00018-013-1514-y] [Citation(s) in RCA: 132] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2013] [Revised: 10/17/2013] [Accepted: 11/07/2013] [Indexed: 12/14/2022]
Abstract
The insulin-like growth factor type 1 receptor (IGF-1R) plays a key role in the development and progression of cancer; however, therapeutics targeting it have had disappointing results in the clinic. As a receptor tyrosine kinase (RTK), IGF-1R is traditionally described as an ON/OFF system, with ligand stabilizing the ON state and exclusive kinase-dependent signaling activation. Newly added to the traditional model, ubiquitin-mediated receptor downregulation and degradation was originally described as a response to ligand/receptor interaction and thus inseparable from kinase signaling activation. Yet, the classical model has proven over-simplified and insufficient to explain experimental evidence accumulated over the last decade, including kinase-independent signaling, unbalanced signaling, or dissociation between signaling and receptor downregulation. Based on the recent findings that IGF-1R “borrows” components of G-protein coupled receptor (GPCR) signaling, including β-arrestins and G-protein-related kinases, we discuss the emerging paradigm for the IGF-1R as a functional RTK/GPCR hybrid, which integrates the kinase signaling with the IGF-1R canonical GPCR characteristics. The contradictions to the classical IGF-1R signaling concept as well as the design of anti-IGF-1R therapeutics treatment are considered in the light of this paradigm shift and we advocate recognition of IGF-1R as a valid target for cancer treatment.
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IGF-1 activates a cilium-localized noncanonical Gβγ signaling pathway that regulates cell-cycle progression. Dev Cell 2013; 26:358-68. [PMID: 23954591 DOI: 10.1016/j.devcel.2013.07.014] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 05/28/2013] [Accepted: 07/17/2013] [Indexed: 02/03/2023]
Abstract
Primary cilia undergo cell-cycle-dependent assembly and disassembly. Emerging data suggest that ciliary resorption is a checkpoint for S phase reentry and that the activation of phospho(T94)Tctex-1 couples these two events. However, the environmental cues and molecular mechanisms that trigger these processes remain unknown. Here, we show that insulin-like growth-1 (IGF-1) accelerates G1-S progression by causing cilia to resorb. The mitogenic signals of IGF-1 are predominantly transduced through IGF-1 receptor (IGF-1R) on the cilia of fibroblasts and epithelial cells. At the base of the cilium, phosphorylated IGF-1R activates an AGS3-regulated Gβγ signaling pathway that subsequently recruits phospho(T94)Tctex-1 to the transition zone. Perturbing any component of this pathway in cortical progenitors induces premature neuronal differentiation at the expense of proliferation. These data suggest that during corticogenesis, a cilium-transduced, noncanonical IGF-1R-Gβγ-phospho(T94)Tctex-1 signaling pathway promotes the proliferation of neural progenitors through modulation of ciliary resorption and G1 length.
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18
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Insulin/IGF-1 signaling, including class II/III PI3Ks, β-arrestin and SGK-1, is required in C. elegans to maintain pharyngeal muscle performance during starvation. PLoS One 2013; 8:e63851. [PMID: 23700438 PMCID: PMC3659082 DOI: 10.1371/journal.pone.0063851] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 04/06/2013] [Indexed: 01/07/2023] Open
Abstract
In C. elegans, pharyngeal pumping is regulated by the presence of bacteria. In response to food deprivation, the pumping rate rapidly declines by about 50–60%, but then recovers gradually to baseline levels on food after 24 hr. We used this system to study the role of insulin/IGF-1 signaling (IIS) in the recovery of pharyngeal pumping during starvation. Mutant strains with reduced function in the insulin/IGF-1 receptor, DAF-2, various insulins (INS-1 and INS-18), and molecules that regulate insulin release (UNC-64 and NCA-1; NCA-2) failed to recover normal pumping rates after food deprivation. Similarly, reduction or loss of function in downstream signaling molecules (e.g., ARR-1, AKT-1, and SGK-1) and effectors (e.g., CCA-1 and UNC-68) impaired pumping recovery. Pharmacological studies with kinase and metabolic inhibitors implicated class II/III phosphatidylinositol 3-kinases (PI3Ks) and glucose metabolism in the recovery response. Interestingly, both over- and under-activity in IIS was associated with poorer recovery kinetics. Taken together, the data suggest that optimum levels of IIS are required to maintain high levels of pharyngeal pumping during starvation. This work may ultimately provide insights into the connections between IIS, nutritional status and sarcopenia, a hallmark feature of aging in muscle.
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Identification of novel signalling roles and targets for G(α) and G(βγ) downstream of the insulin-like growth factor 1 receptor in vascular smooth muscle cells. Biochem J 2013. [PMID: 23186281 DOI: 10.1042/bj20112158] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Vascular dysfunction is the underlying cause of nearly 80% of heart disease cases, and its initiation and progression can be exacerbated by circulating factors, such as IGF-1 (insulin-like growth factor 1). IGF-1, which is highly homologous with insulin, elicits a response via a classical tyrosine kinase receptor, the IGF-1R (IGF-1 receptor). However, it has been suggested that the IGF-1R may also be coupled to a heterotrimeric G-protein and can thus modulate cellular processes via this alternate pathway. The objective of the present study was to investigate the structural aspects of IGF-1R coupling to a heterotrimeric G-protein in VSMCs [vascular SMCs (smooth muscle cells)], as well as examine the contribution of this pathway to cellular responses that are related to vascular disease. We found that the intracellular subunit of the IGF-1R precipitates with two G-protein subunits. The G(βγ)-mediated pathway contributes to both proliferation and migration. We also show that IGF-1 specifically activates G(αi) and can directly interact with both G(αi1) and G(αi2). A phospho-screen using a novel specific G(αi)-peptide inhibitor reveals a number of potential downstream effectors of this pathway, although our results show that it is not essential for SMC proliferation or migration.
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Amritraj A, Posse de Chaves EI, Hawkes C, Macdonald RG, Kar S. Single-transmembrane domain IGF-II/M6P receptor: potential interaction with G protein and its association with cholesterol-rich membrane domains. Endocrinology 2012; 153:4784-98. [PMID: 22903618 DOI: 10.1210/en.2012-1139] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The IGF-II/mannose 6-phosphate (M6P) receptor is a single-transmembrane domain glycoprotein that plays an important role in the intracellular trafficking of lysosomal enzymes and endocytosis-mediated degradation of IGF-II. The receptor may also mediate certain biological effects in response to IGF-II binding by interacting with G proteins. However, the nature of the IGF-II/M6P receptor's interaction with the G protein or with G protein-coupled receptor (GPCR) interacting proteins such as β-arrestin remains unclear. Here we report that [(125)I]IGF-II receptor binding in the rat hippocampal formation is sensitive to guanosine-5'-[γ-thio]triphosphate, mastoparan, and Mas-7, which are known to interfere with the coupling of the classical GPCR with G protein. Monovalent and divalent cations also influenced [(125)I]IGF-II receptor binding. The IGF-II/M6P receptor, as observed for several GPCRs, was found to be associated with β-arrestin 2, which exhibits sustained ubiquitination after stimulation with Leu(27)IGF-II, an IGF-II analog that binds rather selectively to the IGF-II/M6P receptor. Activation of the receptor by Leu(27)IGF-II induced stimulation of extracellular signal-related kinase 1/2 via a pertussis toxin-dependent pathway. Additionally, we have shown that IGF-II/M6P receptors under normal conditions are associated mostly with detergent-resistant membrane domains, but after stimulation with Leu(27)IGF-II, are translocated to the detergent-soluble fraction along with a portion of β-arrestin 2. Collectively these results suggest that the IGF-II/M6P receptor may interact either directly or indirectly with G protein as well as β-arrestin 2, and activation of the receptor by an agonist can lead to alteration in its subcellular distribution along with stimulation of an intracellular signaling cascade.
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Affiliation(s)
- Asha Amritraj
- Department of Psychiatry, Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
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Khambata RS, Panayiotou CM, Hobbs AJ. Natriuretic peptide receptor-3 underpins the disparate regulation of endothelial and vascular smooth muscle cell proliferation by C-type natriuretic peptide. Br J Pharmacol 2012; 164:584-97. [PMID: 21457229 PMCID: PMC3178781 DOI: 10.1111/j.1476-5381.2011.01400.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND AND PURPOSE C-type natriuretic peptide (CNP) is an endothelium-derived vasorelaxant, exerting anti-atherogenic actions in the vasculature and salvaging the myocardium from ischaemic injury. The cytoprotective effects of CNP are mediated in part via the Gi-coupled natriuretic peptide receptor (NPR)3. As GPCRs are well-known to control cell proliferation, we investigated if NPR3 activation underlies effects of CNP on endothelial and vascular smooth muscle cell mitogenesis. EXPERIMENTAL APPROACH Proliferation of human umbilical vein endothelial cells (HUVEC), rat aortic smooth muscle cells (RAoSMC) and endothelial and vascular smooth muscle cells from NPR3 knockout (KO) mice was investigated in vitro. KEY RESULTS CNP (1 pM–1 µM) facilitated HUVEC proliferation and inhibited RAoSMC growth concentration-dependently. The pro- and anti-mitogenic effects of CNP were blocked by the NPR3 antagonist M372049 (10 µM) and the extracellular signal-regulated kinase (ERK) 1/2 inhibitor PD98059 (30 µM) and were absent in cells from NPR3 KO mice. Activation of ERK 1/2 by CNP was inhibited by Pertussis toxin (100 ng·mL−1) and M372049 (10 µM). In HUVEC, ERK 1/2 activation enhanced expression of the cell cycle promoter, cyclin D1, whereas in RAoSMC, ERK 1/2 activation increased expression of the cell cycle inhibitors p21waf1/cip1 and p27kip1. CONCLUSIONS AND IMPLICATIONS A facet of the vasoprotective profile of CNP is mediated via NPR3-dependent ERK 1/2 phosphorylation, resulting in augmented endothelial cell proliferation and inhibition of vascular smooth muscle growth. This pathway may offer an innovative approach to reversing the endothelial damage and vascular smooth muscle hyperplasia that characterize many vascular disorders.
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Loss ES, Jacobus AP, Wassermann GF. Rapid signaling responses in Sertoli cell membranes induced by follicle stimulating hormone and testosterone: calcium inflow and electrophysiological changes. Life Sci 2011; 89:577-83. [PMID: 21703282 DOI: 10.1016/j.lfs.2011.05.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Revised: 05/04/2011] [Accepted: 05/25/2011] [Indexed: 10/18/2022]
Abstract
This minireview describes the rapid signaling actions of follicle stimulating hormone (FSH) and testosterone in immature Sertoli cells mainly related to Ca(2+) inflow and the electrophysiological changes produced by hormones. The rapid membrane actions of FSH occur in a time frame of seconds to minutes, which include membrane depolarization and the stimulation of (45)Ca(2+) uptake. These effects can be prevented by pertussis toxin (PTX), suggesting that they are likely mediated by Gi-protein coupled receptor activation. Furthermore, these effects were inhibited by verapamil, a blocker of the L-type voltage-dependent Ca(2+) channel (VDCC). Finally, FSH stimulation of (45)Ca(2+) uptake was inhibited by the (phosphoinositide 3-kinase) PI3K inhibitor wortmannin. These results suggest that the rapid action of FSH on L-type Ca(2+) channel activity in Sertoli cells from pre-pubertal rats is mediated by the Gi/Gβγ/PI3Kγ pathway, independent of its effects on insulin-like growth factor type I (IGF-I). Testosterone depolarizes the membrane potential and increases the resistance and the (45)Ca(2+) uptake in Sertoli cells of the seminiferous tubules of immature rats. These actions were nullified by diazoxide (K(+)(ATP) channel opener). Testosterone actions were blocked by both PTX and the phospholipase C (PLC) inhibitor U73122, suggesting the involvement of PLC - phosphatidylinositol 4-5 bisphosphate (PIP2) hydrolysis via the Gq protein in the testosterone-mediated pathway. These results indicate that testosterone acts on the Sertoli cell membrane through the K(+)(ATP) channels and PLC-PIP2 hydrolysis, which closes the channel, depolarizes the membrane and stimulates (45)Ca(2+) uptake. These results demonstrate the existence of rapid non-classical pathways in immature Sertoli cells regulated by FSH and testosterone.
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Affiliation(s)
- Eloísa S Loss
- Laboratório de Endocrinologia Experimental e Eletrofisiologia Endócrina Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite 500, Porto Alegre/RS, Brazil
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Pyne NJ, Pyne S. Receptor tyrosine kinase-G-protein-coupled receptor signalling platforms: out of the shadow? Trends Pharmacol Sci 2011; 32:443-50. [PMID: 21612832 DOI: 10.1016/j.tips.2011.04.002] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Revised: 04/20/2011] [Accepted: 04/26/2011] [Indexed: 12/29/2022]
Abstract
Receptor tyrosine kinases (RTKs) and G-protein-coupled receptors (GPCRs) can form platforms in which protein signalling components specific for each receptor are shared (owing to close proximity) to produce an integrated response upon engagement of ligands. RTK-GPCR signalling platforms respond to growth factors and GPCR agonists to increase gain over and above that which is normally produced by separate receptors. They can also function to change the spatial context of signalling in response to growth factor activation. The function of RTK-GPCR signalling platforms can be modulated with conformational-specific inhibitors that stabilise defined GPCR states to abrogate both GPCR agonist- and growth factor-stimulated cell responses. In this paper, we provide an opinion of the biology and unusual pharmacology of RTK-GPCR signalling platforms and make comparisons with a more traditional model of crosstalk between RTKs and GPCRs.
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Affiliation(s)
- Nigel J Pyne
- Cell Biology Group, Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow, G4 0RE, UK.
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Jacobus AP, Loss ES, Wassermann GF. Pertussis toxin nullifies the depolarization of the membrane potential and the stimulation of the rapid phase of Ca entry through L-type calcium channels that are produced by follicle stimulating hormone in 10- to 12-day-old rat Sertoli cells. Front Physiol 2010; 1:138. [PMID: 21423378 PMCID: PMC3059968 DOI: 10.3389/fphys.2010.00138] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Accepted: 09/15/2010] [Indexed: 11/20/2022] Open
Abstract
The aim of this study was to evaluate the effect of pertussis toxin (PTX) on the depolarizing component of the action of follicle stimulating hormone (FSH) on the membrane potential (MP) of Sertoli cells, which is linked to the rapid entry of Ca2+ into cells and to the Ca2+-dependent transport of neutral amino acids by the A system. This model allowed us to analyze the involvement of Gi proteins in the action of FSH in these phenomena. In parallel, using an inactive analog of insulin-like growth factor type I (IGF-1), JB1, and an anti-IGF-I antibody we investigated the possible mediating role of IGF-I on these effects of FSH because IGF-I is produced and released by testicular cells in response to stimulation by FSH and shows depolarization effects on MP similar to those from FSH. Our results have the following implications: (a) the rapid membrane actions of FSH, which occur in a time-frame of seconds to minutes and include the depolarization of the MP, and stimulation of 45Ca2+ uptake and [14C]-methyl aminoisobutyric acid ([14C]-MeAIB) transport, are nullified by the action of PTX and, therefore, are probably mediated by GiPCR activation; (b) the effects of FSH were also nullified by verapamil, an L-type voltage-dependent Ca2+ channel blocker; (c) wortmannin, an inhibitor of phosphoinositide 3-kinase (PI3K), prevented FSH stimulation of 45Ca2+ entry and [14C]-MeAIB transport; and (d) these FSH actions are independent of the IGF-I effects. In conclusion, these results strongly suggest that the rapid action of FSH on L-type Ca2+ channel activity in Sertoli cells from 10- to 12-day-old rats is mediated by the Gi/βγ/PI3Kγ pathway, independent of the effects of IGF-I.
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Affiliation(s)
- Ana Paula Jacobus
- Laboratório de Endocrinologia Experimental e Eletrofisiologia Endócrina, Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul Porto Alegre, Rio Grande do Sul, Brazil
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García-Sáinz JA, Romero-Ávila MT, Medina LDC. Dissecting how receptor tyrosine kinases modulate G protein-coupled receptor function. Eur J Pharmacol 2010; 648:1-5. [PMID: 20828551 DOI: 10.1016/j.ejphar.2010.08.049] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2010] [Revised: 08/30/2010] [Accepted: 08/31/2010] [Indexed: 02/06/2023]
Abstract
Receptor tyrosine kinases and G protein-coupled receptors modulate physiological processes and are also involved in the pathogenesis of some diseases. These receptors have intense bidirectional crosstalks leading to interactions in their signaling pathways and also modulation of the receptors themselves. In some cases, the receptor tyrosine kinases phosphorylate G protein-coupled receptors whereas in others phosphoinositide 3-kinase, protein kinase B and protein kinase C are key elements in these crosstalks. Two paracrine/ autocrine processes also participate, i.e., epidermal growth factor transactivation and sphingosine 1-phosphate generation and signaling. G proteins seem to mediate actions of receptor tyrosine kinases, but how this takes place is far from completely understood; some models are presented. Recent data indicate that the mitogen activated protein kinase cascade also mediate crosstalks. In the present perspective these processes are outlined using information from receptors that have been intensively studied, and important gaps in our knowledge are indicated.
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Affiliation(s)
- J Adolfo García-Sáinz
- Departamento de Biología Celular y Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ap. Postal 70-248, México D.F. 04510.
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Weeks KR, Dwyer DS, Aamodt EJ. Antipsychotic drugs activate the C. elegans akt pathway via the DAF-2 insulin/IGF-1 receptor. ACS Chem Neurosci 2010; 1:463-73. [PMID: 22778838 DOI: 10.1021/cn100010p] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2010] [Accepted: 03/15/2010] [Indexed: 01/23/2023] Open
Abstract
The molecular modes of action of antipsychotic drugs are poorly understood beyond their effects at the dopamine D2 receptor. Previous studies have placed Akt signaling downstream of D2 dopamine receptors, and recent data have suggested an association between psychotic illnesses and defective Akt signaling. To characterize the effect of antipsychotic drugs on the Akt pathway, we used the model organism C. elegans, a simple system where the Akt/forkhead box O transcription factor (FOXO) pathway has been well characterized. All major classes of antipsychotic drugs increased signaling through the insulin/Akt/FOXO pathway, whereas four other drugs that are known to affect the central nervous system did not. The antipsychotic drugs inhibited dauer formation, dauer recovery, and shortened lifespan, three biological processes affected by Akt signaling. Genetic analysis showed that AKT-1 and the insulin and insulin-like growth factor receptor, DAF-2, were required for the antipsychotic drugs to increase signaling. Serotonin synthesis was partially involved, whereas the mitogen activated protein kinase (MAPK), SEK-1 is a MAP kinase kinase (MAPKK), and calcineurin were not involved. This is the first example of a common but specific molecular effect produced by all presently known antipsychotic drugs in any biological system. Because untreated schizophrenics have been reported to have low levels of Akt signaling, increased Akt signaling might contribute to the therapeutic actions of antipsychotic drugs.
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Affiliation(s)
- Kathrine R. Weeks
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, Louisiana 71130-3932
| | - Donard S. Dwyer
- Department of Psychiatry and Department of Pharmacology, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, Louisiana 71130-3932
| | - Eric J. Aamodt
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, Louisiana 71130-3932
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Plesneva SA, Kuznetsova LA, Shpakov AO, Sharova TS, Pertseva MN. Study of structural-functional arrangement of the adenylyl cyclase signaling mechanism of action of insulin-like growth factor 1 revealed in muscle tissue of representatives of vertebrates and invertebrates. J EVOL BIOCHEM PHYS+ 2008. [DOI: 10.1134/s0022093008050022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Tso PH, Morris CJ, Yung LY, Ip NY, Wong YH. Multiple Gi Proteins Participate in Nerve Growth Factor-Induced Activation of c-Jun N-terminal Kinases in PC12 Cells. Neurochem Res 2008; 34:1101-12. [DOI: 10.1007/s11064-008-9880-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/23/2008] [Indexed: 01/21/2023]
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29
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Yung LY, Tso PH, Wu EH, Yu JC, Ip NY, Wong YH. Nerve growth factor-induced stimulation of p38 mitogen-activated protein kinase in PC12 cells is partially mediated via Gi/o proteins. Cell Signal 2008; 20:1538-44. [DOI: 10.1016/j.cellsig.2008.04.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2008] [Revised: 04/10/2008] [Accepted: 04/11/2008] [Indexed: 12/21/2022]
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Novosyadlyy R, Kurshan N, Lann D, Vijayakumar A, Yakar S, LeRoith D. Insulin-like growth factor-I protects cells from ER stress-induced apoptosis via enhancement of the adaptive capacity of endoplasmic reticulum. Cell Death Differ 2008; 15:1304-17. [PMID: 18437163 DOI: 10.1038/cdd.2008.52] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Disruption of endoplasmic reticulum (ER) homeostasis causes accumulation of unfolded and misfolded proteins in the ER, triggering the ER stress response, which can eventually lead to apoptosis when ER dysfunction is severe or prolonged. Here we demonstrate that human MCF-7 breast cancer cells, as well as murine NIH/3T3 fibroblasts, are rescued from ER stress-initiated apoptosis by insulin-like growth factor-I (IGF-I). IGF-I significantly augments the adaptive capacity of the ER by enhancing compensatory mechanisms such as the IRE1 alpha-, PERK- and ATF6-mediated arms of ER stress signalling. During ER stress, IGF-I stimulates translational recovery and induces expression of the key molecular chaperone protein Grp78/BiP, thereby enhancing the folding capacity of the ER and promoting recovery from ER stress. We also demonstrate that the antiapoptotic activity of IGF-I during ER stress may be mediated by a novel, as yet unidentified, signalling pathway(s). Application of signal transduction inhibitors of MEK (U1026), PI3K (LY294002 and wortmannin), JNK (SP600125), p38 (SB203580), protein kinases A and C (H-89 and staurosporine) and STAT3 (Stattic) does not prevent IGF-I-mediated protection from ER stress-induced apoptosis. Taken together, these data demonstrate that IGF-I protects against ER stress-induced apoptosis by increasing adaptive mechanisms through enhancement of ER stress-signalling pathways, thereby restoring ER homeostasis and preventing apoptosis.
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Affiliation(s)
- R Novosyadlyy
- Division of Endocrinology, Diabetes and Bone Diseases, The Samuel Bronfman Department of Medicine, Mount Sinai School of Medicine, New York, NY, USA
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Hawkes C, Amritraj A, Macdonald RG, Jhamandas JH, Kar S. Heterotrimeric G proteins and the single-transmembrane domain IGF-II/M6P receptor: functional interaction and relevance to cell signaling. Mol Neurobiol 2008; 35:329-45. [PMID: 17917122 DOI: 10.1007/s12035-007-0021-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2007] [Revised: 11/30/1999] [Accepted: 04/02/2007] [Indexed: 12/11/2022]
Abstract
The G protein-coupled receptor (GPCR) family represents the largest and most versatile group of cell surface receptors. Classical GPCR signaling constitutes ligand binding to a seven-transmembrane domain receptor, receptor interaction with a heterotrimeric G protein, and the subsequent activation or inhibition of downstream intracellular effectors to mediate a cellular response. However, recent reports on direct, receptor-independent G protein activation, G protein-independent signaling by GPCRs, and signaling of nonheptahelical receptors via trimeric G proteins have highlighted the intrinsic complexities of G protein signaling mechanisms. The insulin-like growth factor-II/mannose-6 phosphate (IGF-II/M6P) receptor is a single-transmembrane glycoprotein whose principal function is the intracellular transport of lysosomal enzymes. In addition, the receptor also mediates some biological effects in response to IGF-II binding in both neuronal and nonneuronal systems. Multidisciplinary efforts to elucidate the intracellular signaling pathways that underlie these effects have generated data to suggest that the IGF-II/M6P receptor might mediate transmembrane signaling via a G protein-coupled mechanism. The purpose of this review is to outline the characteristics of traditional and nontraditional GPCRs, to relate the IGF-II/M6P receptor's structure with its role in G protein-coupled signaling and to summarize evidence gathered over the years regarding the putative signaling of the IGF-II/M6P receptor mediated by a G protein.
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Affiliation(s)
- C Hawkes
- Department of Psychiatry, Centre for Alzheimer and Neurodegenerative Research, University of Alberta, Edmonton, AB, T6G 2B7, Canada
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Song RXD, Zhang Z, Chen Y, Bao Y, Santen RJ. Estrogen signaling via a linear pathway involving insulin-like growth factor I receptor, matrix metalloproteinases, and epidermal growth factor receptor to activate mitogen-activated protein kinase in MCF-7 breast cancer cells. Endocrinology 2007; 148:4091-101. [PMID: 17525128 PMCID: PMC2727866 DOI: 10.1210/en.2007-0240] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We present an integrated model of an extranuclear, estrogen receptor-alpha (ERalpha)-mediated, rapid MAPK activation pathway in breast cancer cells. In noncancer cells, IGF-I initiates a linear process involving activation of the IGF-I receptor (IGF-IR) and matrix metalloproteinases (MMP), release of heparin-binding epidermal growth factor (HB-EGF), and activation of EGF receptor (EGFR)-dependent MAPK. 17beta-Estradiol (E2) rapidly activates IGF-IR in breast cancer cells. We hypothesize that E2 induces a similar linear pathway involving IGF-IR, MMP, HB-EGF, EGFR, and MAPK. Using MCF-7 breast cancer cells, we for the first time demonstrated that a sequential activation of IGF-IR, MMP, and EGFR existed in E2 and IGF-I actions, which was supported by evidence that the selective inhibitors of IGF-IR and MMP or knockdown of IGF-IR all inhibited E2- or IGF-I-induced EGFR phosphorylation. Using the inhibitors and small inhibitory RNA strategies, we also demonstrated that the same sequential activation of the receptors occurred in E2-, IGF-I-, but not EGF-induced MAPK phosphorylation. Additionally, a HB-EGF neutralizing antibody significantly blocked E2-induced MAPK activation, further supporting our hypothesis. The biological effects of sequential activation of IGF-IR and EGFR on E2 stimulation of cell proliferation were also investigated. Knockdown or blockade of IGF-IR significantly inhibited E2- or IGF-I-stimulated but not EGF-induced cell growth. Knockdown or blockade of EGFR abrogated cell growth induced by E2, IGF-I, and EGF, indicating that EGFR is a downstream molecule of IGF-IR in E2 and IGF-I action. Together, our data support the novel view that E2 can activate a linear pathway involving the sequential activation of IGF-IR, MMP, HB-EGF, EGFR, and MAPK.
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Affiliation(s)
- Robert X-D Song
- Department of Internal Medicine, University of Virginia School of Medicine, Charlottesville, Virginia 22903, USA
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Wu EHT, Wu KKH, Wong YH. Tuberin: a stimulus-regulated tumor suppressor protein controlled by a diverse array of receptor tyrosine kinases and G protein-coupled receptors. Neurosignals 2007; 15:217-27. [PMID: 17389815 DOI: 10.1159/000101333] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2006] [Accepted: 02/09/2007] [Indexed: 02/02/2023] Open
Abstract
Tuberin, a tumor suppressor protein, is involved in various cellular functions including survival, proliferation, and growth. It has emerged as an important effector regulated by receptor tyrosine kinases (RTKs) and G protein-coupled receptors (GPCRs). Regulation of tuberin by RTKs and GPCRs is highly complex and dependent on the type of receptors and their associated signaling molecules. Apart from Akt, the first kinase recognized to phosphorylate and inactivate tuberin upon growth factor stimulation, an increasing number of kinases upstream of tuberin have been identified. Furthermore, recruitment of different scaffolding adaptor components to the activated receptors appears to play an important role in the regulation of tuberin activity. More recently, the differential regulation of tuberin by various G protein family members have also been intensively studied, it appears that G proteins can both facilitate (e.g., G(i/o)) as well as inhibit (e.g., G(q)) tuberin phosphorylation. In the present review, we attempt to summarize our emerging understandings of the roles of RTKs, GPCRs, and their cross-talk on the regulation of tuberin.
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Affiliation(s)
- Eddy H T Wu
- Department of Biochemistry, Molecular Neuroscience Center, and Biotechnology Research Institute, Hong Kong University of Science and Technology, Hong Kong, SAR, China
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El-Shewy HM, Johnson KR, Lee MH, Jaffa AA, Obeid LM, Luttrell LM. Insulin-like Growth Factors Mediate Heterotrimeric G Protein-dependent ERK1/2 Activation by Transactivating Sphingosine 1-Phosphate Receptors. J Biol Chem 2006. [DOI: 10.1016/s0021-9258(19)84052-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
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Abstract
Receptor tyrosine kinases (RTKs) are a unique family of cell surface receptors, each containing a common intracellular domain that has tyrosine kinase activity. However, RTKs share many signaling molecules with another unique family of cell surface receptors, the seven-transmembrane receptors (7TMRs), and these receptor families can activate similar signaling cascades. In this review of RTK signaling, we describe the role of cross talk between RTKs and 7TMRs, focusing specifically on the role played in this process by beta-arrestins and by G proteins.
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Affiliation(s)
- Christopher J Hupfeld
- Department of Medicine, Division of Endocrinology and Metabolism, University of California San Diego, La Jolla, California 92093, USA.
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El-Shewy HM, Johnson KR, Lee MH, Jaffa AA, Obeid LM, Luttrell LM. Insulin-like growth factors mediate heterotrimeric G protein-dependent ERK1/2 activation by transactivating sphingosine 1-phosphate receptors. J Biol Chem 2006; 281:31399-407. [PMID: 16926156 DOI: 10.1074/jbc.m605339200] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Although several studies have shown that a subset of insulin-like growth factor (IGF) signals require the activation of heterotrimeric G proteins, the molecular mechanisms underlying IGF-stimulated G protein signaling remain poorly understood. Here, we have studied the mechanism by which endogenous IGF receptors activate the ERK1/2 mitogen-activated protein kinase cascade in HEK293 cells. In these cells, treatment with pertussis toxin and expression of a Galpha(q/11)-(305-359) peptide that inhibits G(q/11) signaling additively inhibited IGF-stimulated ERK1/2 activation, indicating that the signal was almost completely G protein-dependent. Treatment with IGF-1 or IGF-2 promoted translocation of green fluorescent protein (GFP)-tagged sphingosine kinase (SK) 1 from the cytosol to the plasma membrane, increased endogenous SK activity within 30 s of stimulation, and caused a statistically significant increase in intracellular and extracellular sphingosine 1-phosphate (S1P) concentration. Using a GFP-tagged S1P1 receptor as a biological sensor for the generation of physiologically relevant S1P levels, we found that IGF-1 and IGF-2 induced GFP-S1P receptor internalization and that the effect was blocked by pretreatment with the SK inhibitor, dimethylsphingosine. Treating cells with dimethylsphingosine, silencing SK1 expression by RNA interference, and blocking endogenous S1P receptors with the competitive antagonist VPC23019 all significantly inhibited IGF-stimulated ERK1/2 activation, suggesting that IGFs elicit G protein-dependent ERK1/2 activation by stimulating SK1-dependent transactivation of S1P receptors. Given the ubiquity of SK and S1P receptor expression, S1P receptor transactivation may represent a general mechanism for G protein-dependent signaling by non-G protein-coupled receptors.
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Affiliation(s)
- Hesham M El-Shewy
- Department of Medicine, Medical University of South Carolina, Charleston, South Carolina 29425, USA
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Kovach SJ, Price JA, Shaw CM, Theodorakis NG, McKillop IH. Role of cyclic-AMP responsive element binding (CREB) proteins in cell proliferation in a rat model of hepatocellular carcinoma. J Cell Physiol 2006; 206:411-9. [PMID: 16110470 DOI: 10.1002/jcp.20474] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The role of cyclic adenosine monophosphate (cAMP) is poorly understood in the regulation of normal and abnormal hepatic cell growth. In this study, we examined the regulation of intracellular cAMP levels and its effect on nuclear cAMP responsive elements (CREs) in a rat model of hepatocellular carcinoma (HCC). Tumorigenic liver cells were cultured from an in vivo model of HCC and the role of cAMP in cell mitogenesis determined. These data demonstrated agents that elevate intracellular cAMP ([cAMP]i) levels caused significant dose-dependent inhibition of serum-stimulated mitogenesis in HCC cells. Cells were next analyzed for transcription factor expression and activity following increased [cAMP]i. These data demonstrated time- and dose-dependent increases in CRE binding protein (pCREB) activity, a maximal response occurring after 10-20 min before returning to basal levels within 60 min. In contrast, increased [cAMP]i levels led to sustained inducible cAMP early repressor (ICER) II/IIgamma mRNA and protein induction. To understand these data in relation to the in vivo setting, HCC tumors were analyzed and compared to pair-matched normal liver (NL) samples. These studies demonstrated significantly elevated Gsalpha-protein expression in HCC versus NL in the absence of significant changes in basal cAMP levels. Analysis of total and active CREB demonstrated significantly increased total CREB/pCREB in HCC versus NL. Further analysis of CRE expression demonstrated significantly increased expression of ICER mRNA and protein in HCC versus sham operated (Sh). These data demonstrate cAMP, while capable of stimulating promitogenic CREB activation inhibits cell mitogenesis in HCC possibly via ICER induction.
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Affiliation(s)
- Stephen J Kovach
- Department of Surgery, University of Rochester Medical Center, Rochester, New York, USA
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Akekawatchai C, Holland JD, Kochetkova M, Wallace JC, McColl SR. Transactivation of CXCR4 by the insulin-like growth factor-1 receptor (IGF-1R) in human MDA-MB-231 breast cancer epithelial cells. J Biol Chem 2005; 280:39701-8. [PMID: 16172123 DOI: 10.1074/jbc.m509829200] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In the multimolecular environment in tissues and organs, cross-talk between growth factor and G protein-coupled receptors is likely to play an important role in both normal and pathological responses. In this report, we demonstrate transactivation of the chemokine receptor CXCR4 by the growth factor insulin-like growth factor (IGF)-1 is required for IGF-1-induced cell migration in metastatic MDA-MB-231 cells. The induction of chemotaxis in MDA-MB-231 cells by IGF-1 was inhibited by pretreatment of the cells with pertussis toxin (PTX) and by RNAi-mediated knockdown of CXCR4. Transactivation of the CXCR4 pathway by IGF-1 occurred independently of CXCL12, the chemokine ligand of CXCR4. Neither CXCR4 knockdown nor PTX had any effect on the ability of IGF-1 to activate IGF-1R, suggesting that CXCR4 and G proteins are activated subsequent to, or independently of, phosphorylation of IGF-1R by IGF-1. Coprecipitation studies revealed the presence of a constitutive complex containing IGF-1R, CXCR4, and the G protein subunits, G(i)alpha2 and Gbeta, and stimulation of MDA-MB-231 cells with IGF-1 led to the release of G(i)alpha2 and Gbeta from CXCR4. Based on our findings, we propose that CXCR4 constitutively forms a complex with IGF-1R in MDA-MB-231 cells, and that this interaction allows IGF-1 to activate migrational signaling pathways through CXCR4, G(i)alpha2 and Gbeta.
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Affiliation(s)
- Chareeporn Akekawatchai
- School of Molecular and Biomedical Science, the University of Adelaide, Adelaide, South Australia, Australia, 5005
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Wu EHT, Wong YH. Pertussis toxin-sensitive Gi/o proteins are involved in nerve growth factor-induced pro-survival Akt signaling cascade in PC12 cells. Cell Signal 2005; 17:881-90. [PMID: 15763430 DOI: 10.1016/j.cellsig.2004.11.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2004] [Accepted: 11/03/2004] [Indexed: 10/26/2022]
Abstract
In Galpha(z)-deficient mice, survival of sympathetic neurons is significantly attenuated in the presence of pertussis toxin (PTX). This suggests that G(i/o) proteins may have distinct roles in neuronal survival. Here, we investigated the possible involvement of G(i/o) proteins in nerve growth factor (NGF)-induced pro-survival phosphatidylinositol-3-kinase (PI3K)/Akt signaling in rat pheochromocytoma PC12 cells. Treatment of PC12 cells with NGF increased the Akt phosphorylation level in a time- and dose-dependent manner. The NGF-dependent Akt activation was partially attenuated by PTX or overexpression of regulators of G protein signaling Z1 (RGSZ1) and Galpha-interacting protein (GAIP)), indicating the participation of G(i/o) proteins. In contrast, epidermal growth factor (EGF)-mediated Akt phosphorylation was unaffected by PTX or RGSZ1 and GAIP. Expression of PTX-resistant mutants of Galpha(i1), Galpha(i3), Galpha(oA), and Galpha(oB), but not Galpha(i2), abolished the inhibitory effect of PTX on NGF-induced Akt activation. The use of transducin as a Gbetagamma scavenger further revealed that Gbetagamma subunits rather than Galpha(i/o) acted as the signal transducer. The activation profiles of Akt-regulated downstream effectors such as Bad, IKK, and nuclear factor-kappaB (NFkappaB) were also examined. NGF-stimulated phosphorylation of Bad and IKK and transcriptional activity of NFkappaB were indeed sensitive to treatments with PTX. This is the first study that demonstrates the involvement of G(i/o) proteins in NGF-induced Akt signaling.
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Affiliation(s)
- Eddy H T Wu
- Department of Biochemistry, the Molecular Neuroscience Center, and the Biotechnology Research Institute, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
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Andrade Ferreira I, Akkerman JWN. IRS-1 and Vascular Complications in Diabetes Mellitus. VITAMINS AND HORMONES 2005; 70:25-67. [PMID: 15727801 DOI: 10.1016/s0083-6729(05)70002-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Abstract
The expected explosive increase in the number of patients with diabetes mellitus will increase the stress on health care. Treatment is focused on preventing vascular complications associated with the disorder. In order to develop better treatment regimens, the field of research has made a great effort in understanding this disorder. This chapter summarizes the current views on the insulin signaling pathway with emphasis on intracellular signaling events associated with insulin resistance, which lead to the prothrombotic condition in the vasculature of patience with diabetes mellitus.
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Affiliation(s)
- I Andrade Ferreira
- Thrombosis and Haemostasis Laboratory, Department of Hematology, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
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41
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Wu EHT, Wong YH. Involvement of G i/o proteins in nerve growth factor-stimulated phosphorylation and degradation of tuberin in PC-12 cells and cortical neurons. Mol Pharmacol 2004; 67:1195-205. [PMID: 15626752 DOI: 10.1124/mol.104.007237] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Tuberin is a critical translation regulator whose role in nerve growth factor (NGF)-promoted neuronal survival has not been documented. In the present study, we examined the ability of NGF to regulate tuberin in PC-12 cells and primary cortical neurons. Incubation of serum-deprived cells with NGF stimulated tuberin phosphorylation and induced proteosome-mediated tuberin degradation. Inhibition of the phosphatidylinositol-3-kinase (PI3K) by wortmannin or overexpression of the kinase dead Akt mutant completely blocked the NGF-induced tuberin phosphorylation and degradation. It is interesting that the NGF-induced tuberin phosphorylation was partially blocked by pertussis toxin or overexpression of regulators of G protein signaling (regulator of G protein signaling Z1 and Galpha-interacting protein), suggesting the participation of G(i/o) proteins. The use of transducin as a Gbetagamma scavenger indicated that Gbetagamma subunits rather than Galpha(i/o) acted as the signal transducer. Epidermal growth factor can similarly induce tuberin phosphorylation and degradation via a PI3K/Akt pathway in PC-12 cells, but these responses were insensitive to pertussis toxin treatment. Treatment of PC-12 cells with a specific agonist to the G(i)-coupled alpha(2)-adrenoceptor also stimulated tuberin phosphorylation transiently, further demonstrating the involvement of G(i/o) signaling in tuberin regulation in PC-12 cells. Finally, overexpression of nonphosphorylable tuberin attenuated NGF-promoted survival of PC-12 cells, suggesting that the phosphorylation and degradation of tuberin are important for NGF-promoted cell survival. Together, this study demonstrates the regulatory effect of NGF and G(i/o) signaling on tuberin.
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Affiliation(s)
- Eddy H T Wu
- Department of Biochemistry, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
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42
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Kreuzer J, Nürnberg B, Krieger-Brauer HI. Ligand-dependent autophosphorylation of the insulin receptor is positively regulated by Gi-proteins. Biochem J 2004; 380:831-6. [PMID: 15025562 PMCID: PMC1224225 DOI: 10.1042/bj20031659] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2003] [Revised: 02/18/2004] [Accepted: 03/16/2004] [Indexed: 11/17/2022]
Abstract
Previously, we have shown that the human insulin receptor (IR) interacts with G(i)2, independent of tyrosine kinase activity and stimulates NADPH oxidase via the Galpha subunit of G(i)2. We have now investigated the regulatory role of G(i)2-proteins in IR function. For the experiments, isolated IRs from plasma membranes of human fat cells were used. The activation of IR autophosphorylation by insulin was blocked by G-protein inactivation through GDPbetaS (guanosine 5'-[beta-thio]disphosphate). Consistently, activation of G-proteins by micromolar concentrations of GTPgammaS (guanosine 5'-[gamma-thio]triphosphate) induced receptor autophosphorylation 5-fold over baseline and increased insulin-induced autophosphorylation by 3-fold. In the presence of 10 microM GTPgammaS, insulin was active at picomolar concentrations, indicating that insulin acted via its cognate receptor. Pretreatment of the plasma membranes with pertussis toxin prevented insulin- and GTPgammaS-induced autophosphorylation, but did not disrupt the IR-G(i)2 complex. The functional nature of the IR-G(i)2 complex was made evident by insulin's ability to increase association of G(i)2 with the IR. This leads to an augmentation of maximal receptor autophosphorylation induced by insulin and GTPgammaS. The specificity of this mechanism was further demonstrated by the use of isolated preactivated G-proteins. Addition of G(i)2alpha and Gbetagamma mimicked maximal response of insulin, whereas Galphas or Galphao had no stimulatory effect. These results define a novel mechanism by which insulin signalling mediates tyrosine kinase activity and autophosphorylation of the IR through recruitment of G(i)-proteins.
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Affiliation(s)
- J Kreuzer
- Innere Medizin III, Universität Heidelberg, Bergheimer Str. 58, D-69115, Heidelberg, Germany
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43
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Moughal NA, Waters C, Sambi B, Pyne S, Pyne NJ. Nerve growth factor signaling involves interaction between the Trk A receptor and lysophosphatidate receptor 1 systems: nuclear translocation of the lysophosphatidate receptor 1 and Trk A receptors in pheochromocytoma 12 cells. Cell Signal 2004; 16:127-36. [PMID: 14607283 DOI: 10.1016/j.cellsig.2003.08.004] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
We report here that the nerve growth factor (NGF) and lysophosphatidate (LPA) receptor signaling systems interact to regulate the p42/p44 MAPK pathway in PC12 cells. This is based upon several lines of evidence. First, the treatment of PC12 cells, which express LPA(1) receptors, with a sub-maximal concentration of LPA and NGF induced synergistic activation of p42/p44 MAPK. Second, the transfection of PC12 cells with LPA(1) receptor anti-sense construct, which reduced the expression of LPA(1), abrogated both LPA- and NGF-stimulated activation of p42/p44 MAPK. Third, the over-expression of recombinant LPA(1) receptor potentiated LPA- and NGF-dependent activation of p42/p44 MAPK. Fourth, the over-expression of C-terminal GRK2 peptide (which sequesters G-protein betagamma subunits) or beta-arrestin I clathrin binding domain (amino acids: 319-418) or pre-treatment of cells with pertussis toxin reduced the LPA- and NGF-dependent stimulation of p42/p44 MAPK. These findings support a model in which the Trk A receptor uses a G-protein-mediated mechanism to regulate the p42/p44 MAPK pathway. Such G-protein-mediated signaling is activated by the LPA(1) receptor as a means of cross-talk regulation with the Trk A receptor. Fifth, the treatment of cells with LPA induced the transactivation of the Trk A receptor. Sixth, LPA and/or NGF stimulated the translocation of tyrosine phosphorylated Trk A receptor and LPA(1) receptor to the nucleus. Taken together, these findings suggest that NGF and LPA exert cross-talk regulation both at the level of p42/p44 MAPK signaling and in the nuclear translocation of LPA(1) and Trk A receptors.
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Affiliation(s)
- Noreen Akhtar Moughal
- Department of Physiology and Pharmacology, Strathclyde Institute for Biomedical Sciences, University of Strathclyde, 27 Taylor St., Glasgow G4 ONR, UK
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44
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Patel TB. Single Transmembrane Spanning Heterotrimeric G Protein-Coupled Receptors and Their Signaling Cascades. Pharmacol Rev 2004; 56:371-85. [PMID: 15317909 DOI: 10.1124/pr.56.3.4] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Heptahelical of serpentine receptors such as the adrenergic receptors are well known to mediate their actions via heterotrimeric GTP-binding proteins. Likewise, receptors that traverse the cell membrane once have been shown to mediate their biological actions by activating several different mechanisms including stimulation of their intrinsic tyrosine kinase activities or the kinase activities of other proteins. Some of these single transmembrane receptors have an intrinsic guanylyl cyclase activity and can stimulate the cyclic GMP second messenger system; however, over the last few years, several studies have shown the involvement of heterotrimeric GTP-binding proteins in mediating signals that eventually culminate in the biological actions of single transmembrane spanning receptors and proteins. These receptors include the receptor tyrosine kinases that mediate the actions of growth factors such as epidermal growth factor, insulin, insulin-like growth factor as well as receptors for atrial natiuretic hormone or the zona pellucida protein (ZP3) and integrins. In this review, the significance of the coupling of the single transmembrane spanning receptors to G proteins has been highlighted by providing several examples of the concept that signaling via these receptors may involve the activation of multiple signaling cascades.
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Affiliation(s)
- Tarun B Patel
- Department of Pharmacology and Experimental Therapeutics, Loyola University Chicago, Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60513, USA.
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Fan H, Peck OM, Tempel GE, Halushka PV, Cook JA. TOLL-LIKE RECEPTOR 4 COUPLED GI PROTEIN SIGNALING PATHWAYS REGULATE EXTRACELLULAR SIGNAL-REGULATED KINASE PHOSPHORYLATION AND AP-1 ACTIVATION INDEPENDENT OF NFκB ACTIVATION. Shock 2004; 22:57-62. [PMID: 15201703 DOI: 10.1097/01.shk.0000129759.58490.d6] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Previous studies have implicated heterotrimeric Gi proteins in signaling leading to inflammatory mediator production induced by lipopolysaccharide (LPS). TLR4 has recently been shown to play a central role in response to LPS activation. We hypothesized that Gi proteins are coupled to TLR4 activation of signaling pathways. To inhibit Gi protein function, human embryonic kidney (HEK) 293 cells or RAW 264.7 cells were pretreated with pertussis toxin (PTx), an inhibitor of receptor-Galphai interaction, or transfected with dominant negative Galphai3 (Galphai3dn) or Galphai2 minigene (an inhibitory carboxyl terminus of Galphai2) plasmid. The cells were subsequently transfected with constitutively active TLR4 (TLR4ca) plasmid or TLR4ca together with an NFkappaB or AP-1 reporter construct. TLR4ca transfection induced ERK 1/2 activation (157 +/- 14%, P < 0.01), AP-1 activation (4.0 +/- 0.2-fold, P < 0.01), and NFkappaB activation (8.1 +/- 0.4-fold, P < 0.01) compared with empty vector controls. Pretreatment with PTx inhibited TLR4ca-induced ERK 1/2 phosphorylation (30 +/- 7%, P < 0.05) and AP-1 activation (36 +/- 3%, P < 0.05) but did not inhibit NFkappaB activation. Cotransfection of TLR4ca with Galphai3dn or Galphai2 minigene also reduced TLR4ca-induced ERK 1/2 phosphorylation (34 +/- 10% and 33 +/- 5%, respectively, P < 0.05). Constitutively active Galphai2 and Galphai3 plasmids potentiated TLR4ca-induced ERK 1/2 phosphorylation (27 +/- 3% and 41 +/- 6%, respectively, P < 0.05). betaARK-ct plasmid, which inhibits the function of betagamma subunit of G protein, has no effect on TLR4ca-induced ERK 1/2 phosphorylation. These data support our hypothesis and provide the first evidence that Galphai-coupled signaling pathways are activated by TLR4. The TLR4-activated Galphai signaling pathway activates ERK 1/2 phosphorylation and AP-1 activation independently of TLR4-mediated signaling to NFkappaB activation.
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Affiliation(s)
- Hongkuan Fan
- Department of Physiology and Neuroscience, Medical University of South Carolina, Charleston, South Carolina 29425, USA
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46
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Waters C, Pyne S, Pyne NJ. The role of G-protein coupled receptors and associated proteins in receptor tyrosine kinase signal transduction. Semin Cell Dev Biol 2004; 15:309-23. [PMID: 15125894 DOI: 10.1016/j.semcdb.2003.12.020] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
It is well established that stimulation of G-protein coupled receptors (GPCRs) can activate signalling from receptor tyrosine kinases by a process termed transactivation. Indeed, in recent years, it has become apparent that transactivation is a general phenomenon that has been demonstrated for many unrelated GPCRs and receptor tyrosine kinases. In this case the GPCR/G-protein participation is up-stream of the receptor tyrosine kinase. Substantial research has addressed these findings but meanwhile another mechanism of cross talk has been slowly emerging. For over a decade, a growing body of evidence has demonstrated that numerous growth factors use G-proteins and attendant signalling molecules such as beta-arrestins that participate down-stream of the receptor tyrosine kinase to signal to effectors, such as p42/p44 MAPK. This review highlights this novel mechanism of cross talk between receptor tyrosine kinases and GPCRs, which is distinct from growth factor receptor transactivation by GPCRs.
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Affiliation(s)
- Catherine Waters
- Department of Physiology and Pharmacology, Strathclyde Institute for Biomedical Sciences, University of Strathclyde, 27 Taylor Street, Glasgow G4 ONR, Scotland, UK
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Voronina E, Wessel GM. Regulatory contribution of heterotrimeric G-proteins to oocyte maturation in the sea urchin. Mech Dev 2004; 121:247-59. [PMID: 15003628 DOI: 10.1016/j.mod.2004.01.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2003] [Revised: 01/14/2004] [Accepted: 01/14/2004] [Indexed: 10/26/2022]
Abstract
Regulation of animal oocyte maturation is hypothesized to involve heterotrimeric G-proteins. It is difficult to test this hypothesis though without knowing what G-proteins are present in these cells and where are they localized. We set out to test the hypothesis that G-proteins regulate maturation in the sea urchin oocyte by identifying resident G-proteins in oocytes and eggs, and then investigating their function. We find four families of G-protein alpha-subunits (Galphai, Galphaq, Galphas, and Galpha12) present in both oocytes and eggs of the sea urchin. Three of them, Galphai, Galphaq, and Galphas are present on the plasma membrane of the oocyte, while the fourth is located on cytoplasmic vesicles. Upon oocyte maturation, these proteins remain in eggs, and continue to be expressed in embryonic tissues. To test the functional contribution of the G-proteins to the regulation of oocyte maturation, we employ specific intervening reagents, including antibodies and competitor peptides to each Galpha subunit, and specific Galpha toxins. We find that Gi is a main candidate for a positive regulator of sea urchin oocyte maturation. These studies provide a foundation to further test specific hypotheses of the G-protein mediated regulation of oocyte maturation, fertilization, and early development in the sea urchin.
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Affiliation(s)
- Ekaterina Voronina
- Department of Molecular and Cell Biology and Biochemistry, Brown University, 69 Brown Street, Providence, RI 02912, USA
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Ibarra C, Estrada M, Carrasco L, Chiong M, Liberona JL, Cardenas C, Díaz-Araya G, Jaimovich E, Lavandero S. Insulin-like growth factor-1 induces an inositol 1,4,5-trisphosphate-dependent increase in nuclear and cytosolic calcium in cultured rat cardiac myocytes. J Biol Chem 2003; 279:7554-65. [PMID: 14660553 DOI: 10.1074/jbc.m311604200] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In the heart, insulin-like growth factor-1 (IGF-1) is a pro-hypertrophic and anti-apoptotic peptide. In cultured rat cardiomyocytes, IGF-1 induced a fast and transient increase in Ca(2+)(i) levels apparent both in the nucleus and cytosol, releasing this ion from intracellular stores through an inositol 1,4,5-trisphosphate (IP(3))-dependent signaling pathway. Intracellular IP(3) levels increased after IGF-1 stimulation in both the presence and absence of extracellular Ca(2+). A different spatial distribution of IP(3) receptor isoforms in cardiomyocytes was found. Ryanodine did not prevent the IGF-1-induced increase of Ca(2+)(i) levels but inhibited the basal and spontaneous Ca(2+)(i) oscillations observed when cardiac myocytes were incubated in Ca(2+)-containing resting media. Spatial analysis of fluorescence images of IGF-1-stimulated cardiomyocytes incubated in Ca(2+)-containing resting media showed an early increase in Ca(2+)(i), initially localized in the nucleus. Calcium imaging suggested that part of the Ca(2+) released by stimulation with IGF-1 was initially contained in the perinuclear region. The IGF-1-induced increase on Ca(2+)(i) levels was prevented by 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-AM, thapsigargin, xestospongin C, 2-aminoethoxy diphenyl borate, U-73122, pertussis toxin, and betaARKct (a peptide inhibitor of Gbetagamma signaling). Pertussis toxin also prevented the IGF-1-dependent IP(3) mass increase. Genistein treatment largely decreased the IGF-1-induced changes in both Ca(2+)(i) and IP(3). LY29402 (but not PD98059) also prevented the IGF-1-dependent Ca(2+)(i) increase. Both pertussis toxin and U73122 prevented the IGF-1-dependent induction of both ERKs and protein kinase B. We conclude that IGF-1 increases Ca(2+)(i) levels in cultured cardiac myocytes through a Gbetagamma subunit of a pertussis toxin-sensitive G protein-PI3K-phospholipase C signaling pathway that involves participation of IP(3).
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Affiliation(s)
- Cristian Ibarra
- Departament de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago
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Orr AW, Pedraza CE, Pallero MA, Elzie CA, Goicoechea S, Strickland DK, Murphy-Ullrich JE. Low density lipoprotein receptor-related protein is a calreticulin coreceptor that signals focal adhesion disassembly. J Cell Biol 2003; 161:1179-89. [PMID: 12821648 PMCID: PMC2172996 DOI: 10.1083/jcb.200302069] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Thrombospondin (TSP) signals focal adhesion disassembly (the intermediate adhesive state) through interactions with cell surface calreticulin (CRT). TSP or a peptide (hep I) of the active site induces focal adhesion disassembly through binding to CRT, which activates phosphoinositide 3-kinase (PI3K) and extracellular signal-related kinase (ERK) through Galphai2 proteins. Because CRT is not a transmembrane protein, it is likely that CRT signals as part of a coreceptor complex. We now show that low density lipoprotein receptor-related protein (LRP) mediates focal adhesion disassembly initiated by TSP binding to CRT. LRP antagonists (antibodies, receptor-associated protein) block hep I/TSP-induced focal adhesion disassembly. LRP is necessary for TSP/hep I signaling because TSP/hep I is unable to stimulate focal adhesion disassembly or ERK or PI3K signaling in fibroblasts deficient in LRP. LRP is important in TSP-CRT signaling, as shown by the ability of hep I to stimulate association of Galphai2 with LRP. The isolated proteins LRP and CRT interact, and LRP and CRT are associated with hep I in molecular complexes extracted from cells. These data establish a mechanism of cell surface CRT signaling through its coreceptor, LRP, and suggest a novel function for LRP in regulating cell adhesion.
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Affiliation(s)
- Anthony Wayne Orr
- Department of Pathology, Division of Molecular and Cellular Pathology and The Cell Adhesion and Matrix Research Center, University of Alabama at Birmingham, VH 668 1530, 3rd Ave. South, Birmingham, AL 35294-0019, USA
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Wan KF, Sambi BS, Tate R, Waters C, Pyne NJ. The inhibitory gamma subunit of the type 6 retinal cGMP phosphodiesterase functions to link c-Src and G-protein-coupled receptor kinase 2 in a signaling unit that regulates p42/p44 mitogen-activated protein kinase by epidermal growth factor. J Biol Chem 2003; 278:18658-63. [PMID: 12624098 DOI: 10.1074/jbc.m212103200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The inhibitory gamma subunit of the retinal photoreceptor type 6 cGMP phosphodiesterase (PDEgamma) is phosphorylated by G-protein-coupled receptor kinase 2 on threonine 62 and regulates the epidermal growth factor- dependent stimulation of p42/p44 mitogen-activated protein kinase in human embryonic kidney 293 cells. We report here that PDEgamma is in a pre-formed complex with c-Src and that stimulation of cells with epidermal growth factor promotes the association of GRK2 with this complex. c-Src has a critical role in the stimulation of the p42/p44 mitogen-activated protein kinase cascade by epidermal growth factor, because c-Src inhibitors block the activation of this kinase by the growth factor. Mutation of Thr-62 (to Ala) in PDEgamma produced a GRK2 phosphorylation-resistant mutant that was less effective in associating with GRK2 in response to epidermal growth factor and did not potentiate the stimulation of p42/p44 mitogen-activated protein kinase by this growth factor. The transcript for a short splice variant version of PDEgamma lacking the Thr-62 phosphorylation site is also expressed in certain mammalian cells and, in common with the Thr-62 mutant, failed to potentiate the stimulatory effect of epidermal growth factor on p42/p44 mitogen-activated protein kinase. The mutation of Thr-22 (to Ala) in PDEgamma, which is a site for phosphorylation by p42/p44 mitogen-activated protein kinase, resulted in a prolonged activation of p42/p44 mitogen-activated protein kinase by epidermal growth factor, suggesting a role for this phosphorylation event in the negative feedback control of PDEgamma.
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Affiliation(s)
- Kah Fei Wan
- Department of Physiology and Pharmacology, Strathclyde Institute for Biomedical Sciences, University of Strathclyde, 27 Taylor Street, Glasgow G4 ONR, Scotland, United Kingdom
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