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Tecalco-Cruz AC, Macías-Silva M, Ramírez-Jarquín JO, Ramírez-Jarquín UN. Decoding the Therapeutic Implications of the ERα Stability and Subcellular Distribution in Breast Cancer. Front Endocrinol (Lausanne) 2022; 13:867448. [PMID: 35498431 PMCID: PMC9044904 DOI: 10.3389/fendo.2022.867448] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 03/03/2022] [Indexed: 01/22/2023] Open
Abstract
Approximately 70% of all breast cancer cases are estrogen receptor-alpha positive (ERα+) and any ERα signaling pathways deregulation is critical for the progression of malignant mammary neoplasia. ERα acts as a transcription factor that promotes the expression of estrogen target genes associated with pro-tumor activity in breast cancer cells. Furthermore, ERα is also part of extranuclear signaling pathways related to endocrine resistance. The regulation of ERα subcellular distribution and protein stability is critical to regulate its functions and, consequently, influence the response to endocrine therapies and progression of this pathology. This minireview highlights studies that have deciphered the molecular mechanisms implicated in controlling ERα stability and nucleo-cytoplasmic transport. These mechanisms offer information about novel biomarkers, therapeutic targets, and promising strategies for breast cancer treatment.
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Affiliation(s)
- Angeles C. Tecalco-Cruz
- Posgrado en Ciencias Genómicas, Universidad Autónoma de la Ciudad de México (UACM), Mexico City, Mexico
- *Correspondence: Angeles C. Tecalco-Cruz, ; Marina Macías-Silva,
| | - Marina Macías-Silva
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico
- *Correspondence: Angeles C. Tecalco-Cruz, ; Marina Macías-Silva,
| | | | - Uri Nimrod Ramírez-Jarquín
- Neural Signal Transduction, Max Planck Florida Institute for Neuroscience, Jupiter, FL, United States
- Instituto Nacional de Cardiología “Ignacio Chávez”, Mexico City, Mexico
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2
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Acconcia F, Fiocchetti M, Busonero C, Fernandez VS, Montalesi E, Cipolletti M, Pallottini V, Marino M. The extra-nuclear interactome of the estrogen receptors: implications for physiological functions. Mol Cell Endocrinol 2021; 538:111452. [PMID: 34500041 DOI: 10.1016/j.mce.2021.111452] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 08/19/2021] [Accepted: 09/02/2021] [Indexed: 02/07/2023]
Abstract
Over the last decades, a great body of evidence has defined a novel view of the cellular mechanism of action of the steroid hormone 17β-estradiol (E2) through its estrogen receptors (i.e., ERα and ERβ). It is now clear that the E2-activated ERs work both as transcription factors and extra-nuclear plasma membrane-localized receptors. The activation of a plethora of signal transduction cascades follows the E2-dependent engagement of plasma membrane-localized ERs and is required for the coordination of gene expression, which ultimately controls the occurrence of the pleiotropic effects of E2. The definition of the molecular mechanisms by which the ERs locate at the cell surface (i.e., palmitoylation and protein association) determined the quest for understanding the specificity of the extra-nuclear E2 signaling. The use of mice models lacking the plasma membrane ERα localization unveiled that the extra-nuclear E2 signaling is operational in vivo but tissue-specific. However, the underlying molecular details for such ERs signaling diversity in the perspective of the E2 physiological functions in the different cellular contexts are still not understood. Therefore, to gain insights into the tissue specificity of the extra-nuclear E2 signaling to physiological functions, here we reviewed the known ERs extra-nuclear interactors and tried to extrapolate from available databases the ERα and ERβ extra-nuclear interactomes. Based on literature data, it is possible to conclude that by specifically binding to extra-nuclear localized proteins in different sub-cellular compartments, the ERs fine-tune their molecular activities. Moreover, we report that the context-dependent diversity of the ERs-mediated extra-nuclear E2 actions can be ascribed to the great flexibility of the physical structures of ERs and the spatial-temporal organization of the logistics of the cells (i.e., the endocytic compartments). Finally, we provide lists of proteins belonging to the potential ERα and ERβ extra-nuclear interactomes and propose that the systematic experimental definition of the ERs extra-nuclear interactomes in different tissues represents the next step for the research in the ERs field. Such characterization will be fundamental for the identification of novel druggable targets for the innovative treatment of ERs-related diseases.
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Affiliation(s)
- Filippo Acconcia
- Department of Sciences, Section Biomedical Sciences, and Technology, University Roma Tre, Viale Guglielmo Marconi, 446, I-00146, Rome, Italy.
| | - Marco Fiocchetti
- Department of Sciences, Section Biomedical Sciences, and Technology, University Roma Tre, Viale Guglielmo Marconi, 446, I-00146, Rome, Italy
| | - Claudia Busonero
- Department of Sciences, Section Biomedical Sciences, and Technology, University Roma Tre, Viale Guglielmo Marconi, 446, I-00146, Rome, Italy
| | - Virginia Solar Fernandez
- Department of Sciences, Section Biomedical Sciences, and Technology, University Roma Tre, Viale Guglielmo Marconi, 446, I-00146, Rome, Italy
| | - Emiliano Montalesi
- Department of Sciences, Section Biomedical Sciences, and Technology, University Roma Tre, Viale Guglielmo Marconi, 446, I-00146, Rome, Italy
| | - Manuela Cipolletti
- Department of Sciences, Section Biomedical Sciences, and Technology, University Roma Tre, Viale Guglielmo Marconi, 446, I-00146, Rome, Italy
| | - Valentina Pallottini
- Department of Sciences, Section Biomedical Sciences, and Technology, University Roma Tre, Viale Guglielmo Marconi, 446, I-00146, Rome, Italy
| | - Maria Marino
- Department of Sciences, Section Biomedical Sciences, and Technology, University Roma Tre, Viale Guglielmo Marconi, 446, I-00146, Rome, Italy.
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3
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Sjøgaard-Frich LM, Prestel A, Pedersen ES, Severin M, Kristensen KK, Olsen JG, Kragelund BB, Pedersen SF. Dynamic Na +/H + exchanger 1 (NHE1) - calmodulin complexes of varying stoichiometry and structure regulate Ca 2+-dependent NHE1 activation. eLife 2021; 10:60889. [PMID: 33655882 PMCID: PMC8009664 DOI: 10.7554/elife.60889] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 03/01/2021] [Indexed: 11/25/2022] Open
Abstract
Calmodulin (CaM) engages in Ca2+-dependent interactions with numerous proteins, including a still incompletely understood physical and functional interaction with the human Na+/H+-exchanger NHE1. Using nuclear magnetic resonance (NMR) spectroscopy, isothermal titration calorimetry, and fibroblasts stably expressing wildtype and mutant NHE1, we discovered multiple accessible states of this functionally important complex existing in different NHE1:CaM stoichiometries and structures. We determined the NMR solution structure of a ternary complex in which CaM links two NHE1 cytosolic tails. In vitro, stoichiometries and affinities could be tuned by variations in NHE1:CaM ratio and calcium ([Ca2+]) and by phosphorylation of S648 in the first CaM-binding α-helix. In cells, Ca2+-CaM-induced NHE1 activity was reduced by mimicking S648 phosphorylation and by mutation of the first CaM-binding α-helix, whereas it was unaffected by inhibition of Akt, one of several kinases phosphorylating S648. Our results demonstrate a diversity of NHE1:CaM interaction modes and suggest that CaM may contribute to NHE1 dimerization and thereby augment NHE1 regulation. We propose that a similar structural diversity is of relevance to many other CaM complexes.
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Affiliation(s)
- Lise M Sjøgaard-Frich
- Section for Cell Biology and Physiology, Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Andreas Prestel
- Structural Biology and NMR Laboratory, Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Emilie S Pedersen
- Structural Biology and NMR Laboratory, Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Marc Severin
- Section for Cell Biology and Physiology, Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Kristian Kølby Kristensen
- Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark.,Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen, Denmark
| | - Johan G Olsen
- Structural Biology and NMR Laboratory, Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Birthe B Kragelund
- Structural Biology and NMR Laboratory, Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Stine Falsig Pedersen
- Section for Cell Biology and Physiology, Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
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4
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Tran QK. Reciprocality Between Estrogen Biology and Calcium Signaling in the Cardiovascular System. Front Endocrinol (Lausanne) 2020; 11:568203. [PMID: 33133016 PMCID: PMC7550652 DOI: 10.3389/fendo.2020.568203] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 08/19/2020] [Indexed: 12/30/2022] Open
Abstract
17β-Estradiol (E2) is the main estrogenic hormone in the body and exerts many cardiovascular protective effects. Via three receptors known to date, including estrogen receptors α (ERα) and β (ERβ) and the G protein-coupled estrogen receptor 1 (GPER, aka GPR30), E2 regulates numerous calcium-dependent activities in cardiovascular tissues. Nevertheless, effects of E2 and its receptors on components of the calcium signaling machinery (CSM), the underlying mechanisms, and the linked functional impact are only beginning to be elucidated. A picture is emerging of the reciprocality between estrogen biology and Ca2+ signaling. Therein, E2 and GPER, via both E2-dependent and E2-independent actions, moderate Ca2+-dependent activities; in turn, ERα and GPER are regulated by Ca2+ at the receptor level and downstream signaling via a feedforward loop. This article reviews current understanding of the effects of E2 and its receptors on the cardiovascular CSM and vice versa with a focus on mechanisms and combined functional impact. An overview of the main CSM components in cardiovascular tissues will be first provided, followed by a brief review of estrogen receptors and their Ca2+-dependent regulation. The effects of estrogenic agonists to stimulate acute Ca2+ signals will then be reviewed. Subsequently, E2-dependent and E2-independent effects of GPER on components of the Ca2+ signals triggered by other stimuli will be discussed. Finally, a case study will illustrate how the many mechanisms are coordinated to moderate Ca2+-dependent activities in the cardiovascular system.
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Zhang M, Li Z, Jang H, Hedman AC, Sacks DB, Nussinov R. Ca 2+-Dependent Switch of Calmodulin Interaction Mode with Tandem IQ Motifs in the Scaffolding Protein IQGAP1. Biochemistry 2019; 58:4903-4911. [PMID: 31724397 PMCID: PMC8195445 DOI: 10.1021/acs.biochem.9b00854] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
IQ domain GTPase-activating scaffolding protein 1 (IQGAP1) mediates cytoskeleton, cell migration, proliferation, and apoptosis events. Calmodulin (CaM) modulates IQGAP1 functions by binding to its four tandem IQ motifs. Exactly how CaM binds the IQ motifs and which functions of IQGAP1 CaM regulates and how are fundamental mechanistic questions. We combine experimental pull-down assays, mutational data, and molecular dynamics simulations to understand the IQ-CaM complexes with and without Ca2+ at the atomic level. Apo-CaM favors the IQ3 and IQ4 motifs but not the IQ1 and IQ2 motifs that lack two hydrophobic residues for interactions with apo-CaM's hydrophobic pocket. Ca2+-CaM binds all four IQ motifs, with both N- and C-lobes tightly wrapped around each motif. Ca2+ promotes IQ-CaM interactions and increases the amount of IQGAP1-loaded CaM for IQGAP1-mediated signaling. Collectively, we describe IQ-CaM binding in atomistic detail and feature the emergence of Ca2+ as a key modulator of the CaM-IQGAP1 interactions.
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Affiliation(s)
- Mingzhen Zhang
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland 20892, United States
| | - Zhigang Li
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Hyunbum Jang
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Andrew C. Hedman
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - David B. Sacks
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Ruth Nussinov
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland 20892, United States
- Sackler Institute of Molecular Medicine, Department of Human Genetics and Molecular Medicine, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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Lappano R, Mallet C, Rizzuti B, Grande F, Galli GR, Byrne C, Broutin I, Boudieu L, Eschalier A, Jacquot Y, Maggiolini M. The Peptide ERα17p Is a GPER Inverse Agonist that Exerts Antiproliferative Effects in Breast Cancer Cells. Cells 2019; 8:cells8060590. [PMID: 31207943 PMCID: PMC6627388 DOI: 10.3390/cells8060590] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 06/13/2019] [Indexed: 12/18/2022] Open
Abstract
The inhibition of the G protein-coupled estrogen receptor (GPER) offers promising perspectives for the treatment of breast tumors. A peptide corresponding to part of the hinge region/AF2 domain of the human estrogen receptor α (ERα17p, residues 295–311) exerts anti-proliferative effects in various breast cancer cells including those used as triple negative breast cancer (TNBC) models. As preliminary investigations have evoked a role for the GPER in the mechanism of action of this peptide, we focused our studies on this protein using SkBr3 breast cancer cells, which are ideal for GPER evaluation. ERα17p inhibits cell growth by targeting membrane signaling. Identified as a GPER inverse agonist, it co-localizes with GPER and induces the proteasome-dependent downregulation of GPER. It also decreases the level of pEGFR (phosphorylation of epidermal growth factor receptor), pERK1/2 (phosphorylation of extracellular signal-regulated kinase), and c-fos. ERα17p is rapidly distributed in mice after intra-peritoneal injection and is found primarily in the mammary glands. The N-terminal PLMI motif, which presents analogies with the GPER antagonist PBX1, reproduces the effect of the whole ERα17p. Thus, this motif seems to direct the action of the entire peptide, as highlighted by docking and molecular dynamics studies. Consequently, the tetrapeptide PLMI, which can be claimed as the first peptidic GPER disruptor, could open new avenues for specific GPER modulators.
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Affiliation(s)
- Rosamaria Lappano
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036 Rende, Italy.
| | - Christophe Mallet
- NEURO-DOL Basics & Clinical Pharmacology of Pain, INSERM, CHU, Université Clermont Auvergne, F-63000 Clermont-Ferrand, France.
- ANALGESIA Institute, Université Clermont Auvergne, F-63000 Clermont-Ferrand, France.
| | - Bruno Rizzuti
- CNR-NANOTEC, Licryl-UOS Cosenza and CEMIF.Cal, Department of Physics, University of Calabria, 87036 Rende, Italy.
| | - Fedora Grande
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036 Rende, Italy.
| | - Giulia Raffaella Galli
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036 Rende, Italy.
| | - Cillian Byrne
- Laboratoire des Biomolécules (LBM), CNRS-UMR 7203, Sorbonne University, Ecole Normale Supérieure, 75252 Paris Cedex 05, France.
| | - Isabelle Broutin
- Cibles Thérapeutiques et Conception de Médicaments (CiTCoM), CNRS-UMR 8038, Faculté des Sciences Pharmaceutiques et Biologiques, Université Paris Descartes, 75270 Paris Cedex 06, France.
| | - Ludivine Boudieu
- NEURO-DOL Basics & Clinical Pharmacology of Pain, INSERM, CHU, Université Clermont Auvergne, F-63000 Clermont-Ferrand, France.
- ANALGESIA Institute, Université Clermont Auvergne, F-63000 Clermont-Ferrand, France.
| | - Alain Eschalier
- NEURO-DOL Basics & Clinical Pharmacology of Pain, INSERM, CHU, Université Clermont Auvergne, F-63000 Clermont-Ferrand, France.
- ANALGESIA Institute, Université Clermont Auvergne, F-63000 Clermont-Ferrand, France.
| | - Yves Jacquot
- Laboratoire des Biomolécules (LBM), CNRS-UMR 7203, Sorbonne University, Ecole Normale Supérieure, 75252 Paris Cedex 05, France.
| | - Marcello Maggiolini
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036 Rende, Italy.
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7
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Qin S, Ingle JN, Liu M, Yu J, Wickerham DL, Kubo M, Weinshilboum RM, Wang L. Calmodulin-like protein 3 is an estrogen receptor alpha coregulator for gene expression and drug response in a SNP, estrogen, and SERM-dependent fashion. Breast Cancer Res 2017; 19:95. [PMID: 28821270 PMCID: PMC5562991 DOI: 10.1186/s13058-017-0890-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 08/04/2017] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND We previously performed a case-control genome-wide association study in women treated with selective estrogen receptor modulators (SERMs) for breast cancer prevention and identified single nucleotide polymorphisms (SNPs) in ZNF423 as potential biomarkers for response to SERM therapy. The ZNF423rs9940645 SNP, which is approximately 200 bp away from the estrogen response elements, resulted in the SNP, estrogen, and SERM-dependent regulation of ZNF423 expression and, "downstream", that of BRCA1. METHODS Electrophoretic mobility shift assay-mass spectrometry was performed to identify proteins binding to the ZNF423 SNP and coordinating with estrogen receptor alpha (ERα). Clustered, regularly interspaced short palindromic repeats (CRISPR)/Cas9 genome editing was applied to generate ZR75-1 breast cancer cells with different ZNF423 SNP genotypes. Both cultured cells and mouse xenograft models with different ZNF423 SNP genotypes were used to study the cellular responses to SERMs and poly(ADP-ribose) polymerase (PARP) inhibitors. RESULTS We identified calmodulin-like protein 3 (CALML3) as a key sensor of this SNP and a coregulator of ERα, which contributes to differential gene transcription regulation in an estrogen and SERM-dependent fashion. Furthermore, using CRISPR/Cas9-engineered ZR75-1 breast cancer cells with different ZNF423 SNP genotypes, striking differences in cellular responses to SERMs and PARP inhibitors, alone or in combination, were observed not only in cells but also in a mouse xenograft model. CONCLUSIONS Our results have demonstrated the mechanism by which the ZNF423 rs9940645 SNP might regulate gene expression and drug response as well as its potential role in achieving more highly individualized breast cancer therapy.
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Affiliation(s)
- Sisi Qin
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA
| | - James N Ingle
- Department of Medical Oncology, Mayo Clinic, Rochester, MN, USA
| | - Mohan Liu
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA
| | - Jia Yu
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA
| | - D Lawrence Wickerham
- Section of Cancer Genetics and Prevention, Allegheny Health Network Cancer Institute, Pittsburgh, PA, USA.,National Surgical Adjuvant Breast and Bowel Project (NRG Oncology), Pittsburgh, PA, USA
| | - Michiaki Kubo
- Laboratory for Genotyping Development, Center for Genomic Medicine, RIKEN, Yokohama, Japan
| | - Richard M Weinshilboum
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA
| | - Liewei Wang
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA.
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8
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Li Z, Zhang Y, Hedman AC, Ames JB, Sacks DB. Calmodulin Lobes Facilitate Dimerization and Activation of Estrogen Receptor-α. J Biol Chem 2017; 292:4614-4622. [PMID: 28174300 DOI: 10.1074/jbc.m116.754804] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2016] [Revised: 01/30/2017] [Indexed: 02/03/2023] Open
Abstract
Estrogen receptor α (ER-α) is a nuclear hormone receptor that controls selected genes, thereby regulating proliferation and differentiation of target tissues, such as breast. Gene expression controlled by ER-α is modulated by Ca2+ via calmodulin (CaM). Here we present the NMR structure of Ca2+-CaM bound to two molecules of ER-α (residues 287-305). The two lobes of CaM bind to the same site on two separate ER-α molecules (residues 292, 296, 299, 302, and 303), which explains why CaM binds two molecules of ER-α in a 1:2 complex and stabilizes ER-α dimerization. Exposed glutamate residues in CaM (Glu-11, Glu-14, Glu-84, and Glu-87) form salt bridges with key lysine residues in ER-α (Lys-299, Lys-302, and Lys-303), which is likely to prevent ubiquitination at these sites and inhibit degradation of ER-α. Transfection of cells with full-length CaM slightly increased the ability of estrogen to enhance transcriptional activation by ER-α of endogenous estrogen-responsive genes. By contrast, expression of either the N- or C-lobe of CaM abrogated estrogen-stimulated transcription of the estrogen responsive genes pS2 and progesterone receptor. These data suggest that CaM-induced dimerization of ER-α is required for estrogen-stimulated transcriptional activation by the receptor. In light of the critical role of ER-α in breast carcinoma, our data suggest that small molecules that selectively disrupt the interaction of ER-α with CaM may be useful in the therapy of breast carcinoma.
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Affiliation(s)
- Zhigang Li
- From the Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892
| | - Yonghong Zhang
- the Department of Chemistry, University of Texas Rio Grande Valley, Edinburgh, Texas 78539, and
| | - Andrew C Hedman
- From the Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892
| | - James B Ames
- the Department of Chemistry, University of California, Davis, California 95616
| | - David B Sacks
- From the Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892,
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9
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Tran QK, Firkins R, Giles J, Francis S, Matnishian V, Tran P, VerMeer M, Jasurda J, Burgard MA, Gebert-Oberle B. Estrogen Enhances Linkage in the Vascular Endothelial Calmodulin Network via a Feedforward Mechanism at the G Protein-coupled Estrogen Receptor 1. J Biol Chem 2016; 291:10805-23. [PMID: 26987903 DOI: 10.1074/jbc.m115.697334] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Indexed: 12/13/2022] Open
Abstract
Estrogen exerts many effects on the vascular endothelium. Calmodulin (CaM) is the transducer of Ca(2+) signals and is a limiting factor in cardiovascular tissues. It is unknown whether and how estrogen modifies endothelial functions via the network of CaM-dependent proteins. Here we show that 17β-estradiol (E2) up-regulates total CaM level in endothelial cells. Concurrent measurement of Ca(2+) and Ca(2+)-CaM indicated that E2 also increases free Ca(2+)-CaM. Pharmacological studies, gene silencing, and receptor expression-specific cell studies indicated that the G protein-coupled estrogen receptor 1 (GPER/GPR30) mediates these effects via transactivation of EGFR and subsequent MAPK activation. The outcomes were then examined on four distinct members of the intracellular CaM target network, including GPER/GPR30 itself and estrogen receptor α, the plasma membrane Ca(2+)-ATPase (PMCA), and endothelial nitric-oxide synthase (eNOS). E2 substantially increases CaM binding to estrogen receptor α and GPER/GPR30. Mutations that reduced CaM binding to GPER/GPR30 in separate binding domains do not affect GPER/GPR30-Gβγ preassociation but decrease GPER/GPR30-mediated ERK1/2 phosphorylation. E2 increases CaM-PMCA association, but the expected stimulation of Ca(2+) efflux is reversed by E2-stimulated tyrosine phosphorylation of PMCA. These effects sustain Ca(2+) signals and promote Ca(2+)-dependent CaM interactions with other CaM targets. Consequently, E2 doubles CaM-eNOS interaction and also promotes dual phosphorylation of eNOS at Ser-617 and Ser-1179. Calculations using in-cell and in vitro data revealed substantial individual and combined contribution of these effects to total eNOS activity. Taken together, E2 generates a feedforward loop via GPER/GPR30, which enhances Ca(2+)/CaM signals and functional linkage in the endothelial CaM target network.
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Affiliation(s)
- Quang-Kim Tran
- From the Department of Physiology and Pharmacology, College of Osteopathic Medicine, Des Moines University, Des Moines, Iowa 50312
| | - Rachel Firkins
- From the Department of Physiology and Pharmacology, College of Osteopathic Medicine, Des Moines University, Des Moines, Iowa 50312
| | - Jennifer Giles
- From the Department of Physiology and Pharmacology, College of Osteopathic Medicine, Des Moines University, Des Moines, Iowa 50312
| | - Sarah Francis
- From the Department of Physiology and Pharmacology, College of Osteopathic Medicine, Des Moines University, Des Moines, Iowa 50312
| | - Vahe Matnishian
- From the Department of Physiology and Pharmacology, College of Osteopathic Medicine, Des Moines University, Des Moines, Iowa 50312
| | - Phuong Tran
- From the Department of Physiology and Pharmacology, College of Osteopathic Medicine, Des Moines University, Des Moines, Iowa 50312
| | - Mark VerMeer
- From the Department of Physiology and Pharmacology, College of Osteopathic Medicine, Des Moines University, Des Moines, Iowa 50312
| | - Jake Jasurda
- From the Department of Physiology and Pharmacology, College of Osteopathic Medicine, Des Moines University, Des Moines, Iowa 50312
| | - Michelle Ann Burgard
- From the Department of Physiology and Pharmacology, College of Osteopathic Medicine, Des Moines University, Des Moines, Iowa 50312
| | - Briana Gebert-Oberle
- From the Department of Physiology and Pharmacology, College of Osteopathic Medicine, Des Moines University, Des Moines, Iowa 50312
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10
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Exploring the dynamics of cell processes through simulations of fluorescence microscopy experiments. Biophys J 2016; 108:2613-8. [PMID: 26039162 DOI: 10.1016/j.bpj.2015.04.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 03/12/2015] [Accepted: 04/09/2015] [Indexed: 11/21/2022] Open
Abstract
Fluorescence correlation spectroscopy (FCS) methods are powerful tools for unveiling the dynamical organization of cells. For simple cases, such as molecules passively moving in a homogeneous media, FCS analysis yields analytical functions that can be fitted to the experimental data to recover the phenomenological rate parameters. Unfortunately, many dynamical processes in cells do not follow these simple models, and in many instances it is not possible to obtain an analytical function through a theoretical analysis of a more complex model. In such cases, experimental analysis can be combined with Monte Carlo simulations to aid in interpretation of the data. In response to this need, we developed a method called FERNET (Fluorescence Emission Recipes and Numerical routines Toolkit) based on Monte Carlo simulations and the MCell-Blender platform, which was designed to treat the reaction-diffusion problem under realistic scenarios. This method enables us to set complex geometries of the simulation space, distribute molecules among different compartments, and define interspecies reactions with selected kinetic constants, diffusion coefficients, and species brightness. We apply this method to simulate single- and multiple-point FCS, photon-counting histogram analysis, raster image correlation spectroscopy, and two-color fluorescence cross-correlation spectroscopy. We believe that this new program could be very useful for predicting and understanding the output of fluorescence microscopy experiments.
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11
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In vitro and in vivo effects of tamoxifen against larval stage Echinococcus granulosus. Antimicrob Agents Chemother 2014; 58:5146-54. [PMID: 24936598 DOI: 10.1128/aac.02113-13] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Cystic echinococcosis is a zoonotic infection caused by the larval stage of the cestode Echinococcus granulosus. Chemotherapy currently employs benzimidazoles; however, 40% of cases do not respond favorably. With regard to these difficulties, novel therapeutic tools are needed to optimize treatment in humans. The aim of this work was to explore the in vitro and in vivo effects of tamoxifen (TAM) against E. granulosus. In addition, possible mechanisms for the susceptibility of TAM are discussed in relation to calcium homeostasis, P-glycoprotein inhibition, and antagonist effects on a putative steroid receptor. After 24 h of treatment, TAM, at a low micromolar concentration range (10 to 50 μM), inhibited the survival of E. granulosus protoscoleces and metacestodes. Moreover, we demonstrated the chemotherapeutic and chemopreventive pharmacological effects of the drug. At a dose rate of 20 mg/kg of body weight, TAM induced protection against the infection in mice. In the clinical efficacy studies, a reduction in cyst weight was observed after the administration of 20 mg/kg in mice with cysts developed during 3 or 6 months, compared to that of those collected from control mice. Since the collateral effects of high TAM doses have been largely documented in clinical trials, the use of low doses of this drug as a short-term therapy may be a novel alternative approach for human cystic echinococcosis treatment.
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Tran QK, VerMeer M. Biosensor-based approach identifies four distinct calmodulin-binding domains in the G protein-coupled estrogen receptor 1. PLoS One 2014; 9:e89669. [PMID: 24586950 PMCID: PMC3931812 DOI: 10.1371/journal.pone.0089669] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 01/22/2014] [Indexed: 01/24/2023] Open
Abstract
The G protein-coupled estrogen receptor 1 (GPER) has been demonstrated to participate in many cellular functions, but its regulatory inputs are not clearly understood. Here we describe a new approach that identifies GPER as a calmodulin-binding protein, locates interaction sites, and characterizes their binding properties. GPER coimmunoprecipitates with calmodulin in primary vascular smooth muscle cells under resting conditions, which is enhanced upon acute treatment with either specific ligands or a Ca(2+)-elevating agent. To confirm direct interaction and locate the calmodulin-binding domain(s), we designed a series of FRET biosensors that consist of enhanced cyan and yellow fluorescent proteins flanking each of GPER's submembrane domains (SMDs). Responses of these biosensors showed that all four submembrane domains directly bind calmodulin. Modifications of biosensor linker identified domains that display the strongest calmodulin-binding affinities and largest biosensor dynamics, including a.a. 83-93, 150-175, 242-259, 330-351, corresponding respectively to SMDs 1, 2, 3, and the juxta-membranous section of SMD4. These biosensors bind calmodulin in a strictly Ca(2+)-dependent fashion and with disparate affinities in the order SMD2>SMD4>SMD3>SMD1, apparent K d values being 0.44 ± 0.03, 1.40 ± 0.16, 8.01 ± 0.29, and 136.62 ± 6.56 µM, respectively. Interestingly, simultaneous determinations of biosensor responses and suitable Ca(2+) indicators identified separate Ca(2+) sensitivities for their interactions with calmodulin. SMD1-CaM complexes display a biphasic Ca(2+) response, representing two distinct species (SMD1 sp1 and SMD1 sp2) with drastically different Ca(2+) sensitivities. The Ca(2+) sensitivities of CaM-SMDs interactions follow the order SMD1sp1>SMD4>SMD2>SMD1sp2>SMD3, EC50(Ca(2+)) values being 0.13 ± 0.02, 0.75 ± 0.05, 2.38 ± 0.13, 3.71 ± 0.13, and 5.15 ± 0.25 µM, respectively. These data indicate that calmodulin may regulate GPER-dependent signaling at the receptor level through multiple interaction sites. FRET biosensors represent a simple method to identify unknown calmodulin-binding domains in G protein-coupled receptors and to quantitatively assess binding properties.
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Affiliation(s)
- Quang-Kim Tran
- Department of Physiology & Pharmacology, Des Moines University Osteopathic Medical Center, Des Moines, Iowa, United States of America
- * E-mail:
| | - Mark VerMeer
- Department of Physiology & Pharmacology, Des Moines University Osteopathic Medical Center, Des Moines, Iowa, United States of America
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13
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Erdemir HH, Li Z, Sacks DB. IQGAP1 binds to estrogen receptor-α and modulates its function. J Biol Chem 2014; 289:9100-12. [PMID: 24550401 DOI: 10.1074/jbc.m114.553511] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The estrogen receptor (ER) is a steroid hormone receptor that acts as a transcription factor, modulating genes that regulate a vast range of cellular functions. IQGAP1 interacts with several signaling proteins, cytoskeletal components, and transmembrane receptors, thereby serving as a scaffold to integrate signaling pathways. Both ERα and IQGAP1 contribute to breast cancer. In this study, we report that IQGAP1 binds ERα and ERβ. In vitro analysis with pure proteins revealed a direct interaction between IQGAP1 and ERα. Investigation with multiple short fragments of each protein showed that ERα binds to the IQ domain of IQGAP1, whereas the hinge region of ERα is responsible for binding IQGAP1. In addition, IQGAP1 and ERα co-immunoprecipitated from cells, and the association was modulated by estradiol. The interaction has functional effects. Knockdown of endogenous IQGAP1 attenuated the ability of estradiol to induce transcription of the estrogen-responsive genes pS2, progesterone receptor, and cyclin D1. These data reveal that IQGAP1 binds to ERα and modulates its transcriptional function, suggesting that IQGAP1 might be a target for therapy in patients with breast carcinoma.
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Affiliation(s)
- Huseyin H Erdemir
- From the Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892
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14
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Puzianowska-Kuznicka M, Pawlik-Pachucka E, Owczarz M, Budzińska M, Polosak J. Small-molecule hormones: molecular mechanisms of action. Int J Endocrinol 2013; 2013:601246. [PMID: 23533406 PMCID: PMC3603355 DOI: 10.1155/2013/601246] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Revised: 12/30/2012] [Accepted: 01/17/2013] [Indexed: 01/01/2023] Open
Abstract
Small-molecule hormones play crucial roles in the development and in the maintenance of an adult mammalian organism. On the molecular level, they regulate a plethora of biological pathways. Part of their actions depends on their transcription-regulating properties, exerted by highly specific nuclear receptors which are hormone-dependent transcription factors. Nuclear hormone receptors interact with coactivators, corepressors, basal transcription factors, and other transcription factors in order to modulate the activity of target genes in a manner that is dependent on tissue, age and developmental and pathophysiological states. The biological effect of this mechanism becomes apparent not earlier than 30-60 minutes after hormonal stimulus. In addition, small-molecule hormones modify the function of the cell by a number of nongenomic mechanisms, involving interaction with proteins localized in the plasma membrane, in the cytoplasm, as well as with proteins localized in other cellular membranes and in nonnuclear cellular compartments. The identity of such proteins is still under investigation; however, it seems that extranuclear fractions of nuclear hormone receptors commonly serve this function. A direct interaction of small-molecule hormones with membrane phospholipids and with mRNA is also postulated. In these mechanisms, the reaction to hormonal stimulus appears within seconds or minutes.
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Affiliation(s)
- Monika Puzianowska-Kuznicka
- Department of Human Epigenetics, Mossakowski Medical Research Centre, 5 Pawinskiego Street, 02-106 Warsaw, Poland
- Department of Geriatrics and Gerontology, Medical Center of Postgraduate Education, 61/63 Kleczewska Street, 01-826 Warsaw, Poland
- *Monika Puzianowska-Kuznicka:
| | - Eliza Pawlik-Pachucka
- Department of Human Epigenetics, Mossakowski Medical Research Centre, 5 Pawinskiego Street, 02-106 Warsaw, Poland
- Department of Geriatrics and Gerontology, Medical Center of Postgraduate Education, 61/63 Kleczewska Street, 01-826 Warsaw, Poland
| | - Magdalena Owczarz
- Department of Geriatrics and Gerontology, Medical Center of Postgraduate Education, 61/63 Kleczewska Street, 01-826 Warsaw, Poland
| | - Monika Budzińska
- Department of Geriatrics and Gerontology, Medical Center of Postgraduate Education, 61/63 Kleczewska Street, 01-826 Warsaw, Poland
| | - Jacek Polosak
- Department of Human Epigenetics, Mossakowski Medical Research Centre, 5 Pawinskiego Street, 02-106 Warsaw, Poland
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15
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Carlier L, Byrne C, Miclet E, Bourgoin-Voillard S, Nicaise M, Tabet JC, Desmadril M, Leclercq G, Lequin O, Jacquot Y. Biophysical studies of the interaction between calmodulin and the R287-T311 region of human estrogen receptor α reveals an atypical binding process. Biochem Biophys Res Commun 2012; 419:356-61. [DOI: 10.1016/j.bbrc.2012.02.028] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 02/03/2012] [Indexed: 10/14/2022]
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16
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Zhang Y, Li Z, Sacks DB, Ames JB. Structural basis for Ca2+-induced activation and dimerization of estrogen receptor α by calmodulin. J Biol Chem 2012; 287:9336-44. [PMID: 22275375 DOI: 10.1074/jbc.m111.334797] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The estrogen receptor α (ER-α) regulates expression of target genes implicated in development, metabolism, and breast cancer. Calcium-dependent regulation of ER-α is critical for activating gene expression and is controlled by calmodulin (CaM). Here, we present the NMR structures for the two lobes of CaM each bound to a localized region of ER-α (residues 287-305). A model of the complete CaM·ER-α complex was constructed by combining these two structures with additional data. The two lobes of CaM both compete for binding at the same site on ER-α (residues 292, 296, 299, 302, and 303), which explains why full-length CaM binds two molecules of ER-α in a 1:2 complex and stabilizes ER-α dimerization. Exposed glutamate residues in CaM (Glu(11), Glu(14), Glu(84), and Glu(87)) form salt bridges with key lysine residues in ER-α (Lys(299), Lys(302), and Lys(303)), which are likely to prevent ubiquitination at these sites and inhibit degradation of ER-α. Mutants of ER-α at the CaM-binding site (W292A and K299A) weaken binding to CaM, and I298E/K299D disrupts estrogen-induced transcription. CaM facilitates dimerization of ER-α in the absence of estrogen, and stimulation of ER-α by either Ca(2+) and/or estrogen may serve to regulate transcription in a combinatorial fashion.
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Affiliation(s)
- Yonghong Zhang
- Department of Chemistry, University of California, Davis, California 95616, USA
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17
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White CD, Li Z, Dillon DA, Sacks DB. IQGAP1 protein binds human epidermal growth factor receptor 2 (HER2) and modulates trastuzumab resistance. J Biol Chem 2011; 286:29734-47. [PMID: 21724847 DOI: 10.1074/jbc.m111.220939] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Human epidermal growth factor receptor 2 (HER2) is overexpressed in 20-25% of breast cancers. Increased HER2 expression is an adverse prognostic factor and correlates with decreased patient survival. HER2-positive (HER2(+)) breast cancer is treated with trastuzumab. Unfortunately, some patients are intrinsically refractory to therapy, and many who do respond initially become resistant within 1 year. Understanding the molecular mechanisms underlying HER2 signaling and trastuzumab resistance is essential to reduce breast cancer mortality. IQGAP1 is a ubiquitously expressed scaffold protein that contains multiple protein interaction domains. By regulating its binding partners IQGAP1 integrates signaling pathways, several of which contribute to breast tumorigenesis. We show here that IQGAP1 is overexpressed in HER2(+) breast cancer tissue and binds directly to HER2. Knockdown of IQGAP1 decreases HER2 expression, phosphorylation, signaling, and HER2-stimulated cell proliferation, effects that are all reversed by reconstituting cells with IQGAP1. Reducing IQGAP1 up-regulates p27, and blocking this increase attenuates the growth inhibitory effects of IQGAP1 knockdown. Importantly, IQGAP1 is overexpressed in trastuzumab-resistant breast epithelial cells, and reducing IQGAP1 both augments the inhibitory effects of trastuzumab and restores trastuzumab sensitivity to trastuzumab-resistant SkBR3 cells. These data suggest that inhibiting IQGAP1 function may represent a rational strategy for treating HER2(+) breast carcinoma.
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Affiliation(s)
- Colin D White
- Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02115, USA.
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18
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Xiong LW, Kleerekoper QK, Wang X, Putkey JA. Intra- and interdomain effects due to mutation of calcium-binding sites in calmodulin. J Biol Chem 2010; 285:8094-103. [PMID: 20048169 DOI: 10.1074/jbc.m109.065243] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The IQ-motif protein PEP-19, binds to the C-domain of calmodulin (CaM) with significantly different k(on) and k(off) rates in the presence and absence of Ca(2+), which could play a role in defining the levels of free CaM during Ca(2+) transients. The initial goal of the current study was to determine whether Ca(2+) binding to sites III or IV in the C-domain of CaM was responsible for affecting the kinetics of binding PEP-19. EF-hand Ca(2+)-binding sites were selectively inactivated by the common strategy of changing Asp to Ala at the X-coordination position. Although Ca(2+) binding to both sites III and IV appeared necessary for native-like interactions with PEP-19, the data also indicated that the mutations caused undesirable structural alterations as evidenced by significant changes in amide chemical shifts for apoCaM. Mutations in the C-domain also affected chemical shifts in the unmodified N-domain, and altered the Ca(2+) binding properties of the N-domain. Conversion of Asp(93) to Ala caused the greatest structural perturbations, possibly due to the loss of stabilizing hydrogen bonds between the side chain of Asp(93) and backbone amides in apo loop III. Thus, although these mutations inhibit binding of Ca(2+), the mutated CaM may not be able to support potentially important native-like activity of the apoprotein. This should be taken into account when designing CaM mutants for expression in cell culture.
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Affiliation(s)
- Liang-Wen Xiong
- Department of Biochemistry and Molecular Biology and the Structural Biology Center, University of Texas, Houston Medical School, Houston, Texas 77030, USA
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19
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Martins RST, Fuentes J, Almeida O, Power DM, Canario AVM. Ca(2+)-Calmodulin regulation of testicular androgen production in Mozambique tilapia (Oreochromis mossambicus). Gen Comp Endocrinol 2009; 162:153-9. [PMID: 19341736 DOI: 10.1016/j.ygcen.2009.03.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2008] [Revised: 03/21/2009] [Accepted: 03/24/2009] [Indexed: 11/17/2022]
Abstract
The Ca(2+)-Calmodulin (CaM) signaling pathway has previously been shown to be involved in the regulation of teleost fish ovarian steroidogenesis. However, a putative role of CaM in testicular steroidogenesis and potential targets has not been examined. To examine whether basal steroidogenesis is modulated by Ca(2+) and CaM levels in the testis of Mozambique tilapia (Oreochromis mossambicus) we have incubated testicular fragments in vitro under different conditions and analyzed steroid output. Calcium-free medium with or without EGTA did not affect testicular basal 11-ketotestosterone (11-KT) and testosterone (T) secretion. However, addition of 80microM the CaM inhibitor W7 significantly reduced basal 11-KT, T and androstenedione secretion. Interestingly, the decreased androgen production by 80microM of W7 was accompanied by increased 11-desoxicortisol output and by the activation of cortisol synthesis in the testis, the latter undetected in untreated tissues. However, production of 17,20alpha-dihydroxy-4-pregnen-3-one was unaltered by W7. This suggests that C17,20 desmolase, 21-hydroxylase and possibly 11beta-hydroxysteroid dehydrogenase are targets for CaM. In addition, androgen production was also found to be regulated by the level of cAMP since incubations with forskolin (FK) significantly increased 11-KT and T output. A cross-talk between the cAMP and Ca(2+)-CaM signaling pathways was detected since W7 administration also decreased FK stimulated androgen production. Altogether, these data show that both basal and cAMP stimulated androgen levels were modulated by intracellular Ca(2+)-dependent CaM and that possibly Ca(2+)-CaM determines the shift in steroidogenesis from C21 steroids to androgens.
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Affiliation(s)
- Rute S T Martins
- Centre of Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, Faro, Portugal.
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20
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Zheng F, Luo Y, Wang H. Regulation of brain-derived neurotrophic factor-mediated transcription of the immediate early gene Arc by intracellular calcium and calmodulin. J Neurosci Res 2009; 87:380-92. [PMID: 18798281 DOI: 10.1002/jnr.21863] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The induction of the immediate early gene Arc is strongly implicated in synaptic plasticity. Although the role of ERK has been demonstrated, the regulation of Arc expression is largely unknown. In this study, we investigated the major signaling pathways underlying brain-derived neurotrophic factor (BDNF)-mediated Arc transcription in cultured cortical neurons. The BDNF-stimulated Arc transcription was regulated solely by the Ras-Raf-MAPK signaling through ERK, but not by phosphoinositide 3-kinase (PI3K) and PLC-gamma activities. Although it was demonstrated that BDNF might promote calcium entry through calcium channels and NMDA receptors, chelating extracellular calcium with EGTA failed to block Arc transcription. In contrast, chelating intracellular calcium ([Ca(2+)](i)) by BAPTA-AM abolished BDNF-mediated Arc up-regulation. Surprisingly, BAPTA-AM did not block ERK activation, indicating that [Ca(2+)](i) and Ras-Raf-MAPK are not coupled, and the activation of ERK alone is not sufficient to up-regulate Arc transcription. Moreover, we found that inhibition of calmodulin (CaM) by W13 blocked both Arc transcription and ERK activation, revealing a Ca(2+)-independent function of CaM. These data suggested novel functions of [Ca(2+)](i) and CaM in BDNF signaling. Comparison of the Arc transcription profiles between Ca(2+)-stimulated and BDNF-stimulated neurons demonstrated that the regulatory mechanisms were distinctively tailored to the complex features of neuronal activity. Specifically, PI3K and CaM-dependent protein kinase (CaMK) activity were required for Ca(2+)-stimulated Arc transcription through regulating ERK signaling. Such cross-talks between PI3K, CaMK, and ERK was absent in BDNF-stimulated neurons.
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Affiliation(s)
- Fei Zheng
- Department of Biochemistry, Michigan State University, East Lansing, Michigan, USA
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21
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Brown MD, Bry L, Li Z, Sacks DB. Actin pedestal formation by enteropathogenic Escherichia coli is regulated by IQGAP1, calcium, and calmodulin. J Biol Chem 2008; 283:35212-22. [PMID: 18809683 DOI: 10.1074/jbc.m803477200] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
During infection, enteropathogenic Escherichia coli (EPEC) injects effector proteins into the host cell to manipulate the actin cytoskeleton and promote formation of actin pedestals. IQGAP1 is a multidomain protein that participates in numerous cellular functions, including Rac1/Cdc42 and Ca(2+)/calmodulin signaling and actin polymerization. Here we report that IQGAP1, Ca(2+), and calmodulin modulate actin pedestal formation by EPEC. Infection with EPEC promotes both the interaction of IQGAP1 with calmodulin and the localization of IQGAP1 and calmodulin to actin pedestals while reducing the interaction of IQGAP1 with Rac1 and Cdc42. IQGAP1-null fibroblasts display a reduced polymerization of actin in response to EPEC. In addition, antagonism of calmodulin or chelation of intracellular Ca(2+) reduces EPEC-dependent actin polymerization. Furthermore, IQGAP1 specifically interacts with Tir in vitro and in cells. Together these data identify IQGAP1, Ca(2+), and calmodulin as a novel signaling complex regulating actin pedestal formation by EPEC.
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Affiliation(s)
- Matthew D Brown
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Thorn 530, Boston, Massachusetts 02115, USA
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22
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Gallo D, Jacquot Y, Laurent G, Leclercq G. Calmodulin, a regulatory partner of the estrogen receptor alpha in breast cancer cells. Mol Cell Endocrinol 2008; 291:20-6. [PMID: 18524472 DOI: 10.1016/j.mce.2008.04.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2008] [Revised: 04/14/2008] [Accepted: 04/15/2008] [Indexed: 02/07/2023]
Abstract
Although calmodulin (CaM) interaction with estrogen receptor alpha (ERalpha) has been known for more than two decades, it is only recently that the molecular mechanism of CaM-mediated regulation of ERalpha is beginning to emerge. Others and we have identified a putative calmodulin binding site (P(295)LMIKRSKKNSLALSTADQMVS(317)) in ERalpha, at the boundary between the hinge and the ligand binding domain. ERalpha mutations affecting its association with CaM have been reported to generate high basal, estrogen-independent transactivation activity, indicating that the P(295)-T(317) sequence has an inhibitory function. Moreover, we found that a synthetic peptide (ERalpha17p: P(295)-T(311)) containing residues crucial for CaM binding exerts estrogenic effects on breast carcinoma cells. Finally, computer-aided conformational studies revealed that the CaM binding site might associate with a region located downstream in ERalpha (the beta turn/H4 region), this association likely resulting in an auto-inhibitory folding of the receptor. Thus, we propose as a hypothesis that CaM acts as a positive regulator by relieving this ERalpha auto-inhibition.
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Affiliation(s)
- Dominique Gallo
- Laboratoire J.-C. Heuson de Cancérologie Mammaire, Université Libre de Bruxelles, Institut Jules Bordet, 1 rue Héger-Bordet, B-1000 Brussels, Belgium
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23
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Gallo D, Haddad I, Laurent G, Vinh J, Jacquemotte F, Jacquot Y, Leclercq G. Regulatory function of the P295-T311 motif of the estrogen receptor alpha - does proteasomal degradation of the receptor induce emergence of peptides implicated in estrogenic responses? NUCLEAR RECEPTOR SIGNALING 2008; 6:e007. [PMID: 18432312 PMCID: PMC2329824 DOI: 10.1621/nrs.06007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2007] [Accepted: 04/01/2008] [Indexed: 11/29/2022]
Abstract
The way in which estrogen receptor α (ERα) mediates gene transcription and hormone-dependent cancer cell proliferation is now being largely reconsidered in view of several recent discoveries. ERα-mediated transcription appears to be a cyclic and transient process where the proteasome - and thus receptor degradation - plays a pivotal role. In view of our recent investigations, which demonstrate the estrogenic activity of a synthetic peptide corresponding to a regulatory motif of the receptor (ERα17p), we propose that ERα proteasomal degradation could induce the emergence of regulatory peptide(s). The latter would function as a signal and contribute to the ERα activation process, amplifying the initial hormonal stimulation and giving rise to sustained estrogenic response.
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Affiliation(s)
- Dominique Gallo
- Laboratoire J.-C. Heuson de Cancérologie Mammaire, Université Libre de Bruxelles (ULB), Institut Jules Bordet, Brussels, Belgium
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24
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Berry NB, Fan M, Nephew KP. Estrogen receptor-alpha hinge-region lysines 302 and 303 regulate receptor degradation by the proteasome. Mol Endocrinol 2008; 22:1535-51. [PMID: 18388150 DOI: 10.1210/me.2007-0449] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Cellular levels of estrogen receptor-alpha (ERalpha) protein are regulated primarily by the ubiquitin-proteasome pathway. Dynamic interactions between ERalpha and the protein degradation machinery facilitate the down-regulation process by targeting receptor lysine residues for polyubiquitination. To date, the lysines that control receptor degradation have not been identified. Two receptor lysines, K302 and K303, located in the hinge-region of ERalpha, serve multiple regulatory functions, and we examined whether these might also regulate receptor polyubiquitination, turnover, and receptor-protein interactions. We used ERalpha-negative breast cancer C4-12 cells to generate cells stably expressing wild-type (wt)ERalpha or ERalpha with lysine-to-alanine substitutions at K302 and K303 (ERalpha-AA). In the unliganded state, ERalpha-AA displayed rapid polyubiquitination and enhanced basal turnover, as compared with wtERalpha, due to its elevated association with the ubiquitin ligase carboxy terminus of Hsc70-interacting protein (CHIP) and the proteasome-associated cochaperone Bag1. Treatment of C4-12 cells with either 17beta-estradiol (E2) or the pure antiestrogen ICI 182,780 (ICI) induced rapid degradation of wtERalpha via the ubiquitin-proteasome pathway; however, in the presence of these ligands, ERalpha-AA was less efficiently degraded. Furthermore, ERalpha-AA was resistant to ICI-induced polyubiquitination, suggesting that these lysines are polyubiquitinated in response to the antiestrogen and demonstrate a novel role for these two lysines in the mechanism of action of ICI-induced receptor down-regulation. The reduced stability of ERalpha-AA in the unliganded state and the increased stability of ERalpha-AA in the liganded state were concordant with reporter gene assays demonstrating that ERalpha-AA has lower basal activity but higher E2 inducibility than wtERalpha. These data provide the first evidence that K302/303 protect ERalpha from basal degradation and are necessary for efficient E2- and ICI-induced turnover in breast cancer cells.
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Affiliation(s)
- Nicholas B Berry
- Medical Sciences, Indiana University School of Medicine, Bloomington, IN 47405-4401, USA
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25
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Gallo D, Haddad I, Duvillier H, Jacquemotte F, Laïos I, Laurent G, Jacquot Y, Vinh J, Leclercq G. Trophic effect in MCF-7 cells of ERalpha17p, a peptide corresponding to a platform regulatory motif of the estrogen receptor alpha--underlying mechanisms. J Steroid Biochem Mol Biol 2008; 109:138-49. [PMID: 18262408 DOI: 10.1016/j.jsbmb.2007.12.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2007] [Revised: 11/28/2007] [Accepted: 12/20/2007] [Indexed: 12/31/2022]
Abstract
As yet, estrogen receptor alpha (ERalpha) inhibitors used in clinical practice target a unique site, i.e. the hormone-binding pocket. With the aim of discovering other potential therapeutic targets in the receptor, we studied its AF-2a domain, a site that proves to be critical for ligand-independent ERalpha activity. Previous studies from our laboratory highlighted an auto-inhibitory action associated with a site included in this domain, i.e. the P295-T311 sequence. Accordingly, a deletion of this sequence produces a constitutively activated receptor mutant. More interestingly, a synthetic peptide with the P295-T311 sequence (ERalpha17p) elicits in breast cancer cell lines estrogenic responses that may be ascribed to a competitive mechanism towards the P295-T311-associated auto-inhibition of ERalpha. In the present study, we show that ERalpha17p sustains MCF-7 cell growth in estrogen-depleted culture medium by inducing molecular events promoting G1/S phase transition. We demonstrate, moreover, that this proliferative activity is associated with receptor down regulation (acceleration of ERalpha degradation and repression of ESR1 gene transcription), similar to that induced by estrogen agonists. Complementary studies suggest that our observations may be, at least in part, relevant to a competitive inhibition affecting ERalpha-Hsp70 association. Hence, the design of drugs able to stabilize ERalpha-Hsp70 complexes - where the receptor is in an inactive conformation - may be of therapeutic value.
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Affiliation(s)
- Dominique Gallo
- Laboratoire J.-C. Heuson de Cancérologie Mammaire, Université Libre de Bruxelles, Institut Jules Bordet, 1 rue Héger-Bordet, B-1000 Brussels, Belgium
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26
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Li RW, Capuco AV. Canonical pathways and networks regulated by estrogen in the bovine mammary gland. Funct Integr Genomics 2007; 8:55-68. [PMID: 17668254 DOI: 10.1007/s10142-007-0055-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2007] [Revised: 07/02/2007] [Accepted: 07/04/2007] [Indexed: 02/06/2023]
Abstract
Many attempts have been made to identify estrogen-responsive genes using high-throughput approaches such as microarray, serial analysis of gene expression (SAGE), and in silico prediction. However, few studies have systematically analyzed regulatory networks and pathways affected by estrogen. In this report, we analyzed transcript profiles obtained from 16 prepubertal heifers in a 2 x 2 factorial experiment, with ovarian status (intact or ovariectomized) as the first factor and estrogen treatment as the second (control or estradiol). After 54 h of estrogen treatment, gene expression was evaluated in the parenchyma and fat pad of the bovine mammary gland using a high-density oligonucleotide microarray. The genes significantly regulated by estrogen were subject to pathway and regulatory network analysis using Ingenuity Pathways Analysis software. Approximately 2,344 genes responded significantly to estrogen treatment. Of these, 1016 genes were influenced by estrogen regardless of tissue or ovarian status, while the remaining genes were significant in one of four specific effects of tissue or ovarian status. The canonical pathways significantly regulated by estrogen (P < 0.05) included protein ubiquitination, G2/M cell cycle control, IGF1 signaling, N-glycan biosynthesis, sterol biosynthesis, and oxidative phosphorylation. A total of 23 regulatory networks were identified as estrogen responsive. The results provide insight into the molecular mechanisms through which estrogen regulates bovine mammary gland growth and development, supporting the concept that interaction between tissues within the mammary gland promotes mammary epithelial growth.
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Affiliation(s)
- Robert W Li
- Animal and Natural Resources Institute, United States Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705, USA.
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27
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Abstract
IQGAP1 modulates several cellular functions, including cell-cell adhesion, transcription, cytoskeletal architecture, and selected signaling pathways. We previously documented that IQGAP1 binds ERK and MAPK kinase (MEK) and regulates EGF-stimulated MEK and ERK activity. Here we characterize the interaction between IQGAP1 and B-Raf, the molecule immediately upstream of MEK in the Ras/MAPK signaling cascade. B-Raf binds directly to IQGAP1 in vitro and coimmunoprecipitates with IQGAP1 from cell lysates. Importantly, IQGAP1 modulates B-Raf function. EGF is unable to stimulate B-Raf activity in IQGAP1-null cells and in cells transfected with an IQGAP1 mutant construct that is unable to bind B-Raf. Interestingly, binding to IQGAP1 significantly enhances B-Raf activity in vitro. Our data identify a previously unrecognized interaction between IQGAP1 and B-Raf and suggest that IQGAP1 is a scaffold necessary for activation of B-Raf by EGF.
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Affiliation(s)
- Jian-Guo Ren
- Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115
| | - Zhigang Li
- Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115
| | - David B. Sacks
- Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115
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28
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Jacquot Y, Gallo D, Leclercq G. Estrogen receptor alpha--identification by a modeling approach of a potential polyproline II recognizing domain within the AF-2 region of the receptor that would play a role of prime importance in its mechanism of action. J Steroid Biochem Mol Biol 2007; 104:1-10. [PMID: 17258904 DOI: 10.1016/j.jsbmb.2006.10.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2006] [Accepted: 10/02/2006] [Indexed: 11/16/2022]
Abstract
Estrogen receptors (ERs) behave not only as ligand-dependent transcriptional factors; they can also trigger non-genomic responses involving mitogen activated protein kinases (MAPKs), reported to be crucial in transduction cascades. MAPKs are partially activated by proteins with domains able to interact with polyproline II (PPII) regions. Recent studies have brought up the direct interaction of PPII-containing proteins with the alpha subtype human ER (ERalpha). Such observations suggest that ERalpha may contain a "PPII recognizing domain" (PRD). By sequence alignment, we identified such a potential PRD within the AF-2 region of ERalpha (residues 351-414). According to our modeling studies based on X-ray structural data, this PRD appears to be divided in two sub-regions known to interact with alpha-helix containing coactivators. Our data also reveal the potential existence of intramolecular interactions of this domain with a large PPII-rich region of the receptor (residues 301-330). Implication of these regulatory structural elements in both genomic and non-genomic responses seems likely.
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Affiliation(s)
- Yves Jacquot
- Université Pierre et Marie Curie-Paris 6, CNRS, UMR 7613, Synthèse, Structure et Fonction de Molécules Bioactives, FR 2769, Case courrier 45, 4, place Jussieu, 75005 Paris, France.
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29
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Gallo D, Jacquemotte F, Cleeren A, Laïos I, Hadiy S, Rowlands MG, Caille O, Nonclercq D, Laurent G, Jacquot Y, Leclercq G. Calmodulin-independent, agonistic properties of a peptide containing the calmodulin binding site of estrogen receptor alpha. Mol Cell Endocrinol 2007; 268:37-49. [PMID: 17316976 DOI: 10.1016/j.mce.2007.01.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2006] [Revised: 01/15/2007] [Accepted: 01/18/2007] [Indexed: 11/23/2022]
Abstract
Calmodulin (CaM) contributes to estrogen receptor alpha (ER)-mediated transcription. In order to study the underlying mechanisms, we synthesized a peptide including the CaM binding site: ERalpha17p (P(295)-T(311)). This peptide inhibited ER-CaM association, unlike two analogs in which two amino acids required for CaM binding were substituted. Exposure of MCF-7 cells to ERalpha17p down regulated ER, stimulated ER-dependent transcription and enhanced the proliferation of ER-positive breast cancer cell lines. Interestingly, ERalpha17p analogs unable to bind to CaM induced similar responses, demonstrating that ERalpha17p-mediated effects are mainly relevant to mechanisms independent of ER-CaM dissociation. The P(295)-T(311) motif is indeed a platform for multiple post-translational modifications not necessarily CaM-dependent. The additional finding that deletion of the P(295)-T(311) sequence in ER produced a constitutive transcriptional activity revealed that this platform motif has autorepressive functions. With regard to cell function, association of CaM to ER would counteract this autorepression, leading thereby to enhanced ER-mediated transactivation.
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Affiliation(s)
- Dominique Gallo
- Laboratoire J.-C. Heuson de Cancérologie Mammaire, Université Libre de Bruxelles, Institut Jules Bordet, 1 rue Héger-Bordet, B-1000 Brussels, Belgium
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30
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Penolazzi L, Zennaro M, Lambertini E, Tavanti E, Torreggiani E, Gambari R, Piva R. Induction of estrogen receptor alpha expression with decoy oligonucleotide targeted to NFATc1 binding sites in osteoblasts. Mol Pharmacol 2007; 71:1457-62. [PMID: 17389747 DOI: 10.1124/mol.107.034561] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The nuclear factor of activated T cell cytoplasmic 1 (NFATc1) is a member of the NFAT family and is strictly implicated in the growth and development of bone. Most studies have focused on the effects of NFATc1 activation on osteoclastogenesis. On the contrary, the specific roles of NFAT in osteoblast differentiation are not well understood and, in some instances, reports of its role are contradictory. In the present study, we demonstrated that NFATc1 was involved in the transcriptional regulation of human estrogen receptor alpha (ERalpha) gene in SaOS-2 osteoblastic like cells. NFATc1 was specifically recruited "in vivo" at C and F distal promoters of ERalpha gene. In addition, it is here identified as the negative transcription factor removed by the RA4-3'decoy oligonucleotide able to induce ERalpha expression in osteoblasts. Ca(2+)/calcineurin-NFAT-mediated signaling pathways and ERalpha-dependent signals are involved in diverse cellular reactions by regulating gene expression under both physiological and pathological conditions. Therefore, our data might be useful for proper manipulation of NFATc1- and ERalpha-mediated cellular reactions in different bone disorders, such as osteoporosis.
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Affiliation(s)
- Letizia Penolazzi
- Department of Biochemistry and Molecular Biology, Molecular Biology Section, Ferrara, Italy
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31
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Thorogate R, Török K. Role of Ca2+ activation and bilobal structure of calmodulin in nuclear and nucleolar localization. Biochem J 2007; 402:71-80. [PMID: 17040208 PMCID: PMC1783980 DOI: 10.1042/bj20061111] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Ca2+ signalling to the nucleus is thought to occur by calmodulin entry into the nucleus where calmodulin has many functions. In the present study we have investigated the role of Ca2+ and the N- and C-terminal lobes of calmodulin in its subnuclear targeting by using fluorescently labelled calmodulin and its mutants and confocal microscopy. Our data show, first, that Ca2+ stimulation induces a reorganization of subnuclear structures to which apo-calmodulin can bind. Secondly, Ca2+-independent association of the C-terminal lobe is seen with subnuclear structures such as chromatin, the nuclear envelope and the nucleoli. Thirdly, Ca2+-dependent accumulation of both calmodulin and the C-terminal calmodulin lobe occurs in the nucleoli. The N-terminal lobe of calmodulin does not show significant binding to subnuclear structures although, similarly to the C-terminal lobe, it accumulates in the nucleoplasm of wheat germ agglutinin-blocked nuclei suggesting that a facilitated nuclear export mechanism exists for calmodulin.
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Affiliation(s)
- Richard Thorogate
- Division of Basic Medical Sciences, St George's University of London, London SW17 0RE, UK
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32
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Li L, Sacks DB. Functional interactions between calmodulin and estrogen receptor-α. Cell Signal 2007; 19:439-43. [PMID: 17070670 DOI: 10.1016/j.cellsig.2006.08.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2006] [Accepted: 08/29/2006] [Indexed: 02/07/2023]
Abstract
The effects of estrogen in breast epithelial cells are mediated primarily via estrogen receptor alpha and estrogen receptor beta (ERalpha and ERbeta). Accumulating evidence implicates a role for Ca2+ and calmodulin in breast carcinoma, as well as in the function of ERalpha. Calmodulin contributes to the regulation of both ERalpha degradation and ERalpha-mediated transcriptional activation. Recent data will be summarized in this review. Models to explain the molecular mechanisms by which calmodulin modulates ERalpha function are proposed.
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Affiliation(s)
- Lu Li
- Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, United States
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33
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Rodriguez-Mora O, LaHair MM, Howe CJ, McCubrey JA, Franklin RA. Calcium/calmodulin-dependent protein kinases as potential targets in cancer therapy. Expert Opin Ther Targets 2007; 9:791-808. [PMID: 16083343 DOI: 10.1517/14728222.9.4.791] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In this review the authors discuss the expression and activation of a family of protein kinases known as the calcium/calmodulin-dependent kinases (CaM-kinase) and the role that these kinases have in the activation of antiapoptotic signalling pathways. In addition, the authors outline a novel mechanism of activation of these kinases by oxidative stress. Founded on this novel mechanism of activation and the role that these kinases have in activating antiapoptotic signalling pathways, the authors propose that the CaM-kinases would make very good targets for sensitising cancer cells to certain therapeutic treatments. Furthermore, the authors discuss the role that these kinases have in cell transformation and in the regulation of the cell cycle. Based on these roles the authors suggest that inhibition of the CaM-kinases not only has the potential to sensitise cancer cells, but also has the potential to induce cytostasis in these cells.
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Affiliation(s)
- Oswaldo Rodriguez-Mora
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA
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34
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York B, Lou D, Noonan DJ. Tuberin nuclear localization can be regulated by phosphorylation of its carboxyl terminus. Mol Cancer Res 2007; 4:885-97. [PMID: 17114346 DOI: 10.1158/1541-7786.mcr-06-0056] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Tuberin, the tuberous sclerosis 2 (TSC2) gene product, has been identified as a tumor suppressor protein genetically implicated in the pathology of tuberous sclerosis and the female-specific lung disease lymphangioleiomyomatosis. Tuberin and its predominant cytoplasmic binding partner hamartin have been shown to complex with a variety of intracellular signaling regulators and affect the processes of protein translation, cellular proliferation, cellular migration, and cellular transcription. In previous studies, we have presented evidence for tuberin binding to the calcium-dependent intracellular signaling protein calmodulin (CaM), overlap of tuberin CaM binding domain with a binding domain for estrogen receptor alpha, and the phosphorylation-associated nuclear localization of tuberin. In the study presented here, we expand our findings on the mechanism of tuberin nuclear localization to show that the CaM-estrogen receptor-alpha binding domain of tuberin can also serve as a tuberin nuclear localization sequence. Furthermore, we identify an Akt/p90 ribosomal S6 kinase-1 phosphorylation site within the carboxyl terminus of tuberin that can regulate tuberin nuclear localization and significantly affect the ability of tuberin to modulate estrogen genomic signaling events. These findings suggest a link between tuberin nuclear localization and a variety of intracellular signaling events that have direct implications with respect to the role of tuberin in the pathology of tuberous sclerosis and lymphangioleiomyomatosis.
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Affiliation(s)
- Brian York
- Department of Molecular and Cellular Biochemistry, University of Kentucky, 741 South Limestone Avenue, Lexington, KY 40536, USA
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35
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Moens LN, van der Ven K, Van Remortel P, Del-Favero J, De Coen WM. Expression Profiling of Endocrine-Disrupting Compounds Using a Customized Cyprinus carpio cDNA Microarray. Toxicol Sci 2006; 93:298-310. [PMID: 16835292 DOI: 10.1093/toxsci/kfl057] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Exposure to a variety of anthropogenic compounds has been shown to interfere with normal development, physiology, and reproduction in a wide range of organisms, both in laboratory studies and wildlife. We have developed a Cyprinus carpio cDNA microarray consisting of endocrine-related genes. In the current study, we investigated the applicability of this microarray (1) to study the molecular effects induced by exposure to a variety of endocrine-disrupting compounds (EDCs) in fish and (2) to discriminate the specific transcriptional profiles associated with these compounds. To that purpose, gene expression profiles were generated in livers of juvenile carp exposed to 14 Organization of Economical Cooperation Development (OECD)-recommended reference EDCs (17beta-estradiol, 17alpha-ethinylestradiol, 4-nonylphenol, bisphenol A, tamoxifen, 17alpha-methyltestosterone, 11-ketotestosterone, dibutyl phthalate, flutamide, vinclozolin, hydrocortisone, CuCl(2), propylthiouracil, and a mixture of L-triiodothyronine and L-thyroxine). Our results show that, in addition to some expression similarities between analogous acting substances, each individual compound produced its own unique expression pattern on the array, distinct from the profiles generated by the other compounds. In addition, we were able to identify a minimal subset of genes, which also allowed to discriminate between the different compounds. Overall, our findings suggest that the developed cDNA array has great promise to screen new and existing chemicals on their endocrine-disruptive potential and to identify distinct classes of EDCs.
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Affiliation(s)
- Lotte N Moens
- Department of Biology, Laboratory for Ecophysiology, Biochemistry and Toxicology, Intelligent Systems Laboratory, University of Antwerp, B-2020 Antwerp, Belgium.
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36
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Li L, Li Z, Howley PM, Sacks DB. E6AP and calmodulin reciprocally regulate estrogen receptor stability. J Biol Chem 2005; 281:1978-85. [PMID: 16314411 DOI: 10.1074/jbc.m508545200] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Estrogen promotes the proliferation of human breast epithelial cells by interacting with the estrogen receptor (ER). Physiological responses of cells to estrogen are regulated in part by degradation of the ER. Previous studies revealed that calmodulin binds directly to the ER, thereby enhancing its stability. Consistent with these findings, cell-permeable calmodulin antagonists dramatically reduced the number of ER in MCF-7 human breast epithelial cells. Here we investigated the molecular mechanism by which calmodulin attenuates ER degradation. MG132 and lactacystin, inhibitors of the ubiquitin-proteasome pathway, prevented the calmodulin antagonist CGS9343B from reducing the amount of ER in MCF-7 cells. In contrast, protease inhibitors afforded no protection. Moreover, CGS9343B enhanced ER ubiquitination. A point mutant ER construct that is unable to bind calmodulin, termed ERDeltaCaM, is ubiquitinated to a greater extent than wild type ER. The ubiquitin-protein isopeptide ligase E6-associated protein (E6AP) associated with and promoted the degradation of ER. The possible convergence of calmodulin and E6AP on ER degradation was examined. ERDeltaCaM bound E6AP with higher affinity than that of wild type ER. Moreover, calmodulin attenuated the in vitro interaction between ER and E6AP in a Ca(2+)-dependent manner. Collectively, our data reveal that E6AP is a component of ER degradation via the ubiquitin-proteasome pathway and that Ca(2+)/calmodulin modulates this degradation mechanism. These results have potential implications for the development of selectively targeted therapeutic agents for breast cancer.
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Affiliation(s)
- Lu Li
- Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA
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