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Egly CL, Barny LA, Do T, McDonald EF, Knollmann BC, Plate L. The proteostasis interactomes of trafficking-deficient variants of the voltage-gated potassium channel K V11.1 associated with long QT syndrome. J Biol Chem 2024; 300:107465. [PMID: 38876300 DOI: 10.1016/j.jbc.2024.107465] [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: 03/28/2024] [Revised: 05/16/2024] [Accepted: 06/04/2024] [Indexed: 06/16/2024] Open
Abstract
The voltage-gated potassium ion channel KV11.1 plays a critical role in cardiac repolarization. Genetic variants that render Kv11.1 dysfunctional cause long QT syndrome (LQTS), which is associated with fatal arrhythmias. Approximately 90% of LQTS-associated variants cause intracellular protein transport (trafficking) dysfunction, which pharmacological chaperones like E-4031 can rescue. Protein folding and trafficking decisions are regulated by chaperones, protein quality control factors, and trafficking machinery comprising the cellular proteostasis network. Here, we test whether trafficking dysfunction is associated with alterations in the proteostasis network of pathogenic Kv11.1 variants and whether pharmacological chaperones can normalize the proteostasis network of responsive variants. We used affinity-purification coupled with tandem mass tag-based quantitative mass spectrometry to assess protein interaction changes of WT KV11.1 or trafficking-deficient channel variants in the presence or absence of E-4031. We identified 572 core KV11.1 protein interactors. Trafficking-deficient variants KV11.1-G601S and KV11.1-G601S-G965∗ had significantly increased interactions with proteins responsible for folding, trafficking, and degradation compared to WT. We confirmed previous findings that the proteasome is critical for KV11.1 degradation. Our report provides the first comprehensive characterization of protein quality control mechanisms of KV11.1. We find extensive interactome remodeling associated with trafficking-deficient KV11.1 variants and with pharmacological chaperone rescue of KV11.1 cell surface expression. The identified protein interactions could be targeted therapeutically to improve KV11.1 trafficking and treat LQTS.
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Affiliation(s)
- Christian L Egly
- Department of Medicine, Vanderbilt University Medical Center, Nasville, Tennessee, USA
| | - Lea A Barny
- Program in Chemical and Physical Biology, Vanderbilt University, Nashville, Tennessee, USA; Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Tri Do
- Department of Medicine, Vanderbilt University Medical Center, Nasville, Tennessee, USA
| | - Eli F McDonald
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Björn C Knollmann
- Department of Medicine, Vanderbilt University Medical Center, Nasville, Tennessee, USA.
| | - Lars Plate
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA; Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA; Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
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Hu Y, Zhang C, Wang S, Xiong H, Xie W, Zeng Z, Cai H, Wang QK, Lu Z. 14-3-3ε/YWHAE regulates the transcriptional expression of cardiac sodium channel Na V1.5. Heart Rhythm 2024:S1547-5271(24)02557-8. [PMID: 38750908 DOI: 10.1016/j.hrthm.2024.05.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 05/02/2024] [Accepted: 05/07/2024] [Indexed: 06/12/2024]
Abstract
BACKGROUND Cardiac voltage-gated sodium channel alpha subunit 5 (NaV1.5) encoded by SCN5A is associated with arrhythmia disorders. However, the molecular mechanism underlying NaV1.5 expression remains to be fully elucidated. Previous studies have reported that the 14-3-3 family acts as an adaptor involved in regulating kinetic characteristics of cardiac ion channels. OBJECTIVE The purpose of this study was to establish 14-3-3ε/YWHAE, a member of the 14-3-3 family, as a crucial regulator of NaV1.5 and to explore the potential role of 14-3-3ε in the heart. METHODS Western blotting, patch clamping, real-time reverse transcription-polymerase chain reaction, RNA immunoprecipitation, electrocardiogram recording, echocardiography, and histologic analysis were performed. RESULTS YWHAE overexpression significantly reduced the expression level of SCN5A mRNA and sodium current density, whereas YWHAE knockdown significantly increased SCN5A mRNA expression and sodium current density in HEK293/NaV1.5 and H9c2 cells. Similar results were observed in mice injected with adeno-associated virus serotype 9-mediated YWHAE knockdown. The effect of 14-3-3ε on NaV1.5 expression was abrogated by knockdown of TBX5, a transcription factor of NaV1.5. An interaction between 14-3-3ε protein and TBX5 mRNA was identified, and YWHAE overexpression significantly decreased TBX5 mRNA stability without affecting SCN5A mRNA stability. In addition, mice subjected to adeno-associated virus serotype 9-mediated YWHAE knockdown exhibited shorter R-R intervals and higher prevalence of premature ventricular contractions. CONCLUSION Our data unveil a novel regulatory mechanism of NaV1.5 by 14-3-3ε and highlight the significance of 14-3-3ε in transcriptional regulation of NaV1.5 expression and cardiac arrhythmias.
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Affiliation(s)
- Yushuang Hu
- Department of Cardiology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, PR China; Institute of Myocardial Injury and Repair, Wuhan University, Wuhan, Hubei, PR China
| | - Chi Zhang
- Center for Human Genome Research, Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, PR China
| | - Shun Wang
- Department of Cardiology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, PR China; Institute of Myocardial Injury and Repair, Wuhan University, Wuhan, Hubei, PR China
| | - Hongbo Xiong
- Department of Cardiology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, PR China; Institute of Myocardial Injury and Repair, Wuhan University, Wuhan, Hubei, PR China
| | - Wen Xie
- Department of Basic Medicine, Xiamen Medical College, Xiamen, Fujian, PR China
| | - Ziyue Zeng
- Department of Cardiology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, PR China; Institute of Myocardial Injury and Repair, Wuhan University, Wuhan, Hubei, PR China
| | - HuanHuan Cai
- Department of Cardiology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, PR China; Institute of Myocardial Injury and Repair, Wuhan University, Wuhan, Hubei, PR China
| | - Qing Kenneth Wang
- Center for Human Genome Research, Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, PR China
| | - Zhibing Lu
- Department of Cardiology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, PR China; Institute of Myocardial Injury and Repair, Wuhan University, Wuhan, Hubei, PR China.
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Egly CL, Barny L, Do T, McDonald EF, Plate L, Knollmann BC. The proteostasis interactomes of trafficking-deficient K V 11.1 variants associated with Long QT Syndrome and pharmacological chaperone rescue. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.31.574410. [PMID: 38352392 PMCID: PMC10862811 DOI: 10.1101/2024.01.31.574410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/25/2024]
Abstract
Introduction The voltage gated potassium ion channel K V 11.1 plays a critical role in cardiac repolarization. Genetic variants that render Kv11.1 dysfunctional cause Long QT Syndrome (LQTS), which is associated with fatal arrhythmias. Approximately 90% of LQTS-associated variants cause intracellular protein transport (trafficking) dysfunction, which can be rescued by pharmacological chaperones like E-4031. Protein folding and trafficking decisions are regulated by chaperones, protein quality control factors, and trafficking machinery, comprising the cellular proteostasis network. Here, we test whether trafficking dysfunction is associated with alterations in the proteostasis network of pathogenic Kv11.1 variants, and whether pharmacological chaperones can normalize the proteostasis network of responsive variants. Methods We used affinity-purification coupled with tandem mass tag-based quantitative mass spectrometry to assess protein interaction changes in human embryonic kidney (HEK293) cells expressing wild-type (WT) K V 11.1 or trafficking-deficient channel variants in the presence or absence of E-4031. Resultsa We identified 573 core K V 11.1 protein interactors. Both variants K V 11.1-G601S and K V 11.1-G601S-G965* had significantly increased interactions with proteins responsible for folding, trafficking, and degradation compared to WT. We found that proteasomal degradation is a key component for K V 11.1 degradation and that the K V 11.1-G601S-G965* variant was more responsive to E-4031 treatment. This suggests a role in the C-terminal domain and the ER retention motif of K V 11.1 in regulating trafficking. Conclusion Our report characterizes the proteostasis network of K V 11.1, two trafficking deficient K V 11.1 variants, and variants treated with a pharmacological chaperone. The identified protein interactions could be targeted therapeutically to improve K V 11.1 trafficking and treat Long QT Syndrome.
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Zhang Y, Yan M, Yu Y, Wang J, Jiao Y, Zheng M, Zhang S. 14-3-3ε: a protein with complex physiology function but promising therapeutic potential in cancer. Cell Commun Signal 2024; 22:72. [PMID: 38279176 PMCID: PMC10811864 DOI: 10.1186/s12964-023-01420-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 12/02/2023] [Indexed: 01/28/2024] Open
Abstract
Over the past decade, the role of the 14-3-3 protein has received increasing interest. Seven subtypes of 14-3-3 proteins exhibit high homology; however, each subtype maintains its specificity. The 14-3-3ε protein is involved in various physiological processes, including signal transduction, cell proliferation, apoptosis, autophagy, cell cycle regulation, repolarization of cardiac action, cardiac development, intracellular electrolyte homeostasis, neurodevelopment, and innate immunity. It also plays a significant role in the development and progression of various diseases, such as cardiovascular diseases, inflammatory diseases, neurodegenerative disorders, and cancer. These immense and various involvements of 14-3-3ε in diverse processes makes it a promising target for drug development. Although extensive research has been conducted on 14-3-3 dimers, studies on 14-3-3 monomers are limited. This review aimed to provide an overview of recent reports on the molecular mechanisms involved in the regulation of binding partners by 14-3-3ε, focusing on issues that could help advance the frontiers of this field. Video Abstract.
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Affiliation(s)
- Yue Zhang
- Tianjin University of Traditional Chinese Medicine, Tianjin, 301617, People's Republic of China
| | - Man Yan
- Tianjin University of Traditional Chinese Medicine, Tianjin, 301617, People's Republic of China
| | - Yongjun Yu
- Department of Colorectal Surgery, Tianjin Union Medical Center, Tianjin, 300121, People's Republic of China
| | - Jiangping Wang
- Tianjin University of Traditional Chinese Medicine, Tianjin, 301617, People's Republic of China
| | - Yuqi Jiao
- Tianjin University of Traditional Chinese Medicine, Tianjin, 301617, People's Republic of China
| | - Minying Zheng
- Department of Pathology, Tianjin Union Medical Center, Tianjin, 300071, People's Republic of China
| | - Shiwu Zhang
- Department of Pathology, Tianjin Union Medical Center, Tianjin, 300071, People's Republic of China.
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Asrani P, Seebohm G, Stoll R. Potassium viroporins as model systems for understanding eukaryotic ion channel behaviour. Virus Res 2022; 320:198903. [PMID: 36037849 DOI: 10.1016/j.virusres.2022.198903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 08/24/2022] [Accepted: 08/25/2022] [Indexed: 11/29/2022]
Abstract
Ion channels are membrane proteins essential for a plethora of cellular functions including maintaining cell shape, ion homeostasis, cardiac rhythm and action potential in neurons. The complexity and often extensive structure of eukaryotic membrane proteins makes it difficult to understand their basic biological regulation. Therefore, this article suggests, viroporins - the miniature versions of eukaryotic protein homologs from viruses - might serve as model systems to provide insights into behaviour of eukaryotic ion channels in general. The structural requirements for correct assembly of the channel along with the basic functional properties of a K+ channel exist in the minimal design of the viral K+ channels from two viruses, Chlorella virus (Kcv) and Ectocarpus siliculosus virus (Kesv). These small viral proteins readily assemble into tetramers and they sort in cells to distinct target membranes. When these viruses-encoded channels are expressed into the mammalian cells, they utilise their protein machinery and hence can serve as excellent tools to study the cells protein sorting machinery. This combination of small size and robust function makes viral K+ channels a valuable model system for detection of basic structure-function correlations. It is believed that molecular and physiochemical analyses of these viroporins may serve as basis for the development of inhibitors or modulators to ion channel activity for targeting ion channel diseases - so called channelopathies. Therefore, it may provide a potential different scope for molecular pharmacology studies aiming at novel and innovative therapeutics associated with channel related diseases. This article reviews the structural and functional properties of Kcv and Kesv upon expression in mammalian cells and Xenopus oocytes. The mechanisms behind differential protein sorting in Kcv and Kesv are also thoroughly discussed.
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Affiliation(s)
- Purva Asrani
- Biomolecular Spectroscopy and RUBiospec|NMR, Faculty of Chemistry and Biochemistry, Ruhr University of Bochum, Bochum D-44780, Germany
| | - Guiscard Seebohm
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, Münster D-48149, Germany
| | - Raphael Stoll
- Biomolecular Spectroscopy and RUBiospec|NMR, Faculty of Chemistry and Biochemistry, Ruhr University of Bochum, Bochum D-44780, Germany.
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Thompson WC, Goldspink PH. 14-3-3 protein regulation of excitation-contraction coupling. Pflugers Arch 2021; 474:267-279. [PMID: 34820713 PMCID: PMC8837530 DOI: 10.1007/s00424-021-02635-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 10/21/2021] [Accepted: 10/23/2021] [Indexed: 11/25/2022]
Abstract
14-3-3 proteins (14-3-3 s) are a family of highly conserved proteins that regulate many cellular processes in eukaryotes by interacting with a diverse array of client proteins. The 14-3-3 proteins have been implicated in several disease states and previous reviews have condensed the literature with respect to their structure, function, and the regulation of different cellular processes. This review focuses on the growing body of literature exploring the important role 14-3-3 proteins appear to play in regulating the biochemical and biophysical events associated with excitation-contraction coupling (ECC) in muscle. It presents both a timely and unique analysis that seeks to unite studies emphasizing the identification and diversity of 14-3-3 protein function and client protein interactions, as modulators of muscle contraction. It also highlights ideas within these two well-established but intersecting fields that support further investigation with respect to the mechanistic actions of 14-3-3 proteins in the modulation of force generation in muscle.
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Affiliation(s)
- Walter C Thompson
- Department of Physiology and Biophysics (M/C 901) and Center for Cardiovascular Research, College of Medicine, University of Illinois at Chicago, 835 South Wolcott Avenue, RM E-202, Chicago, IL, 60612, USA
| | - Paul H Goldspink
- Department of Physiology and Biophysics (M/C 901) and Center for Cardiovascular Research, College of Medicine, University of Illinois at Chicago, 835 South Wolcott Avenue, RM E-202, Chicago, IL, 60612, USA.
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Chen L, He Y, Wang X, Ge J, Li H. Ventricular voltage-gated ion channels: Detection, characteristics, mechanisms, and drug safety evaluation. Clin Transl Med 2021; 11:e530. [PMID: 34709746 PMCID: PMC8516344 DOI: 10.1002/ctm2.530] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 07/23/2021] [Accepted: 07/26/2021] [Indexed: 02/06/2023] Open
Abstract
Cardiac voltage-gated ion channels (VGICs) play critical roles in mediating cardiac electrophysiological signals, such as action potentials, to maintain normal heart excitability and contraction. Inherited or acquired alterations in the structure, expression, or function of VGICs, as well as VGIC-related side effects of pharmaceutical drug delivery can result in abnormal cellular electrophysiological processes that induce life-threatening cardiac arrhythmias or even sudden cardiac death. Hence, to reduce possible heart-related risks, VGICs must be acknowledged as important targets in drug discovery and safety studies related to cardiac disease. In this review, we first summarize the development and application of electrophysiological techniques that are employed in cardiac VGIC studies alone or in combination with other techniques such as cryoelectron microscopy, optical imaging and optogenetics. Subsequently, we describe the characteristics, structure, mechanisms, and functions of various well-studied VGICs in ventricular myocytes and analyze their roles in and contributions to both physiological cardiac excitability and inherited cardiac diseases. Finally, we address the implications of the structure and function of ventricular VGICs for drug safety evaluation. In summary, multidisciplinary studies on VGICs help researchers discover potential targets of VGICs and novel VGICs in heart, enrich their knowledge of the properties and functions, determine the operation mechanisms of pathological VGICs, and introduce groundbreaking trends in drug therapy strategies, and drug safety evaluation.
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Affiliation(s)
- Lulan Chen
- Department of Cardiology, Shanghai Institute of Cardiovascular DiseasesShanghai Xuhui District Central Hospital & Zhongshan‐xuhui Hospital, Zhongshan Hospital, Fudan UniversityShanghaiChina
| | - Yue He
- Department of CardiologyShanghai Xuhui District Central Hospital & Zhongshan‐xuhui HospitalShanghaiChina
| | - Xiangdong Wang
- Institute of Clinical Science, Zhongshan HospitalFudan UniversityShanghaiChina
| | - Junbo Ge
- Department of Cardiology, Shanghai Institute of Cardiovascular DiseasesShanghai Xuhui District Central Hospital & Zhongshan‐xuhui Hospital, Zhongshan Hospital, Fudan UniversityShanghaiChina
| | - Hua Li
- Department of Cardiology, Shanghai Institute of Cardiovascular DiseasesShanghai Xuhui District Central Hospital & Zhongshan‐xuhui Hospital, Zhongshan Hospital, Fudan UniversityShanghaiChina
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Proteomic Analysis of Exosomes during Cardiogenic Differentiation of Human Pluripotent Stem Cells. Cells 2021; 10:cells10102622. [PMID: 34685602 PMCID: PMC8533815 DOI: 10.3390/cells10102622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 09/23/2021] [Accepted: 09/28/2021] [Indexed: 11/26/2022] Open
Abstract
Efforts to direct the specification of human pluripotent stem cells (hPSCs) to therapeutically important somatic cell types have focused on identifying proper combinations of soluble cues. Yet, whether exosomes, which mediate intercellular communication, play a role in the differentiation remains unexplored. We took a first step toward addressing this question by subjecting hPSCs to stage-wise specification toward cardiomyocytes (CMs) in scalable stirred-suspension cultures and collecting exosomes. Samples underwent liquid chromatography (LC)/mass spectrometry (MS) and subsequent proteomic analysis revealed over 300 unique proteins from four differentiation stages including proteins such as PPP2CA, AFM, MYH9, MYH10, TRA2B, CTNNA1, EHD1, ACTC1, LDHB, and GPC4, which are linked to cardiogenic commitment. There was a significant correlation of the protein composition of exosomes with the hPSC line and stage of commitment. Differentiating hPSCs treated with exosomes from hPSC-derived CMs displayed improved efficiency of CM formation compared to cells without exogenously added vesicles. Collectively, these results demonstrate that exosomes from hPSCs induced along the CM lineage contain proteins linked to the specification process with modulating effects and open avenues for enhancing the biomanufacturing of stem cell products for cardiac diseases.
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Toplak Ž, Hendrickx LA, Abdelaziz R, Shi X, Peigneur S, Tomašič T, Tytgat J, Peterlin-Mašič L, Pardo LA. Overcoming challenges of HERG potassium channel liability through rational design: Eag1 inhibitors for cancer treatment. Med Res Rev 2021; 42:183-226. [PMID: 33945158 DOI: 10.1002/med.21808] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 02/18/2021] [Accepted: 03/31/2021] [Indexed: 12/11/2022]
Abstract
Two decades of research have proven the relevance of ion channel expression for tumor progression in virtually every indication, and it has become clear that inhibition of specific ion channels will eventually become part of the oncology therapeutic arsenal. However, ion channels play relevant roles in all aspects of physiology, and specificity for the tumor tissue remains a challenge to avoid undesired effects. Eag1 (KV 10.1) is a voltage-gated potassium channel whose expression is very restricted in healthy tissues outside of the brain, while it is overexpressed in 70% of human tumors. Inhibition of Eag1 reduces tumor growth, but the search for potent inhibitors for tumor therapy suffers from the structural similarities with the cardiac HERG channel, a major off-target. Existing inhibitors show low specificity between the two channels, and screenings for Eag1 binders are prone to enrichment in compounds that also bind HERG. Rational drug design requires knowledge of the structure of the target and the understanding of structure-function relationships. Recent studies have shown subtle structural differences between Eag1 and HERG channels with profound functional impact. Thus, although both targets' structure is likely too similar to identify leads that exclusively bind to one of the channels, the structural information combined with the new knowledge of the functional relevance of particular residues or areas suggests the possibility of selective targeting of Eag1 in cancer therapies. Further development of selective Eag1 inhibitors can lead to first-in-class compounds for the treatment of different cancers.
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Affiliation(s)
- Žan Toplak
- Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia
| | - Louise A Hendrickx
- Department of Toxicology and Pharmacology, University of Leuven, Leuven, Belgium
| | - Reham Abdelaziz
- AG Oncophysiology, Max-Planck Institute for Experimental Medicine, Göttingen, Germany
| | - Xiaoyi Shi
- AG Oncophysiology, Max-Planck Institute for Experimental Medicine, Göttingen, Germany
| | - Steve Peigneur
- Department of Toxicology and Pharmacology, University of Leuven, Leuven, Belgium
| | - Tihomir Tomašič
- Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia
| | - Jan Tytgat
- Department of Toxicology and Pharmacology, University of Leuven, Leuven, Belgium
| | | | - Luis A Pardo
- AG Oncophysiology, Max-Planck Institute for Experimental Medicine, Göttingen, Germany
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Popescu MC, Lee YJ, Kim SS, Wade HM, Papakyrikos AM, Darling LEO. The phosphorylation state of both hERG and KvLQT1 mediates protein-protein interactions between these complementary cardiac potassium channel alpha subunits. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183556. [PMID: 33444623 DOI: 10.1016/j.bbamem.2021.183556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 12/22/2020] [Accepted: 01/04/2021] [Indexed: 11/16/2022]
Abstract
KvLQT1 and hERG are the α-subunits of the voltage-gated K+ channels which carry the cardiac repolarizing currents IKs and IKr, respectively. These currents function in vivo with some redundancy to maintain appropriate action potential durations (APDs) in cardiomyocytes. As such, protein-protein interactions between hERG and KvLQT1 may be important in normal cardiac electrophysiology, as well as in arrhythmia and sudden cardiac death. Previous phenomenological observations of functional, mutual downregulation between these complementary repolarizing currents in transgenic rabbit models and human cell culture motivate our investigations into protein-protein interactions between hERG and KvLQT1. Previous data suggest that a dynamic, physical interaction between hERG and KvLQT1 modulates the respective currents. However, the mechanism by which hERG-KvLQT1 interactions are regulated is still poorly understood. Phosphorylation is proposed to play a role since modifying the phosphorylation state of each protein has been shown to alter channel kinetics, and both hERG and KvLQT1 are targets of the Ser/Thr protein kinase PKA, activated by elevated intracellular cAMP. In this work, quantitative apFRET analyses of phosphonull and phosphomimetic hERG and KvLQT1 mutants indicate that unphosphorylated hERG does not interact with KvLQT1, suggesting that hERG phosphorylation is important for wild-type proteins to interact. For proteins already potentially interacting, phosphorylation of KvLQT1 appears to be the driving factor abrogating hERG-KvLQT1 interaction. This work increases our knowledge about hERG-KvLQT1 interactions, which may contribute to the efforts to elucidate mechanisms that underlie many types of arrhythmias, and also further characterizes novel protein-protein interactions between two distinct potassium channel families.
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Affiliation(s)
- Medeea C Popescu
- Department of Biological Sciences and Biochemistry Program, Wellesley College, 106 Central St., Wellesley, MA 02481, United States of America
| | - Yeon J Lee
- Department of Biological Sciences and Biochemistry Program, Wellesley College, 106 Central St., Wellesley, MA 02481, United States of America
| | - Stephanie S Kim
- Department of Biological Sciences and Biochemistry Program, Wellesley College, 106 Central St., Wellesley, MA 02481, United States of America
| | - Heidi M Wade
- Department of Biological Sciences and Biochemistry Program, Wellesley College, 106 Central St., Wellesley, MA 02481, United States of America
| | - Amanda M Papakyrikos
- Department of Biological Sciences and Biochemistry Program, Wellesley College, 106 Central St., Wellesley, MA 02481, United States of America
| | - Louise E O Darling
- Department of Biological Sciences and Biochemistry Program, Wellesley College, 106 Central St., Wellesley, MA 02481, United States of America.
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Menzel J, Kownatzki-Danger D, Tokar S, Ballone A, Unthan-Fechner K, Kilisch M, Lenz C, Urlaub H, Mori M, Ottmann C, Shattock MJ, Lehnart SE, Schwappach B. 14-3-3 binding creates a memory of kinase action by stabilizing the modified state of phospholamban. Sci Signal 2020; 13:13/647/eaaz1436. [DOI: 10.1126/scisignal.aaz1436] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The cardiac membrane protein phospholamban (PLN) is targeted by protein kinase A (PKA) at Ser16and by Ca2+/calmodulin-dependent protein kinase II (CaMKII) at Thr17. β-Adrenergic stimulation and PKA-dependent phosphorylation of Ser16acutely stimulate the sarcoplasmic reticulum calcium pump (SERCA) by relieving its inhibition by PLN. CaMKII-dependent phosphorylation may lead to longer-lasting SERCA stimulation and may sustain maladaptive Ca2+handling. Here, we demonstrated that phosphorylation at either Ser16or Thr17converted PLN into a target for the phosphoadaptor protein 14-3-3 with different affinities. 14-3-3 proteins were localized within nanometers of PLN and endogenous 14-3-3 coimmunoprecipitated with pentameric PLN from cardiac membranes. Molecular dynamics simulations predicted different molecular contacts for peptides phosphorylated at Ser16or Thr17with the binding groove of 14-3-3, resulting in varied binding affinities. 14-3-3 binding protected either PLN phosphosite from dephosphorylation. β-Adrenergic stimulation of isolated adult cardiomyocytes resulted in the membrane recruitment of endogenous 14-3-3. The exogenous addition of 14-3-3 to β-adrenergic–stimulated cardiomyocytes led to prolonged SERCA activation, presumably because 14-3-3 protected PLN pentamers from dephosphorylation. Phosphorylation of Ser16was disrupted by the cardiomyopathy-associated ∆Arg14mutation, implying that phosphorylation of Thr17by CaMKII may become crucial for 14-3-3 recruitment to ∆Arg14PLN. Consistent with PLN acting as a dynamic hub in the control of Ca2+handling, our results identify 14-3-3 binding to PLN as a contractility-augmenting mechanism.
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Affiliation(s)
- Julia Menzel
- Department of Molecular Biology, Universitätsmedizin Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Daniel Kownatzki-Danger
- Heart Research Center Göttingen, Department of Cardiology & Pneumology, Universitätsmedizin Göttingen, Robert-Koch-Straße 42a, 37075 Göttingen, Germany
| | - Sergiy Tokar
- School of Cardiovascular Medicine and Sciences, King’s College London, Westminster Bridge Road, London SE17H, UK
| | - Alice Ballone
- Department of Biotechnology, Chemistry and Pharmacy, Department of Excellence 2018-2022, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy
- Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, P. O. Box 513, 5600MB Eindhoven, Netherlands
| | - Kirsten Unthan-Fechner
- Department of Molecular Biology, Universitätsmedizin Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Markus Kilisch
- Department of Molecular Biology, Universitätsmedizin Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Christof Lenz
- Bioanalytics Group, Institute of Clinical Chemistry, University Medical Center Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
- Max-Planck Institute for Biophysical Chemistry, Am Faßberg 11, 37077 Göttingen, Germany
| | - Henning Urlaub
- Bioanalytics Group, Institute of Clinical Chemistry, University Medical Center Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
- Max-Planck Institute for Biophysical Chemistry, Am Faßberg 11, 37077 Göttingen, Germany
| | - Mattia Mori
- Department of Biotechnology, Chemistry and Pharmacy, Department of Excellence 2018-2022, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy
| | - Christian Ottmann
- Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, P. O. Box 513, 5600MB Eindhoven, Netherlands
| | - Michael J. Shattock
- School of Cardiovascular Medicine and Sciences, King’s College London, Westminster Bridge Road, London SE17H, UK
| | - Stephan E. Lehnart
- Heart Research Center Göttingen, Department of Cardiology & Pneumology, Universitätsmedizin Göttingen, Robert-Koch-Straße 42a, 37075 Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells” (MBExC), University of Goettingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
| | - Blanche Schwappach
- Department of Molecular Biology, Universitätsmedizin Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
- Max-Planck Institute for Biophysical Chemistry, Am Faßberg 11, 37077 Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells” (MBExC), University of Goettingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
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12
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Liu Z, Zhang J, Ma A, Wang X, Sun Z, Cui W, Yuan C, Zhu C. Molecular characterization, expression analysis of 14-3-3 beta/alpha and the effect of RNA interference on ion transporter protein Na+-K+-ATPase, Na+–H+-exchanger and CFTR in turbot (Scophthalmus maximus). Comp Biochem Physiol B Biochem Mol Biol 2020; 246-247:110458. [DOI: 10.1016/j.cbpb.2020.110458] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 05/06/2020] [Accepted: 05/11/2020] [Indexed: 10/24/2022]
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13
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Saadeh K, Shivkumar K, Jeevaratnam K. Targeting the β-adrenergic receptor in the clinical management of congenital long QT syndrome. Ann N Y Acad Sci 2020; 1474:27-46. [PMID: 32901453 DOI: 10.1111/nyas.14425] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 05/10/2020] [Accepted: 06/09/2020] [Indexed: 01/01/2023]
Abstract
The long QT syndrome (LQTS) is largely treated pharmacologically with β-blockers, despite the role of sympathetic activity in LQTS being poorly understood. Using the trigger-substrate model of cardiac arrhythmias in this review, we amalgamate current experimental and clinical data from both animal and human studies to explain the mechanism of adrenergic stimulation and blockade on LQT arrhythmic risk and hence assess the efficacy of β-adrenoceptor blockade in the management of LQTS. In LQTS1 and LQTS2, sympathetic stimulation increases arrhythmic risk by enhancing early afterdepolarizations and transmural dispersion of repolarization. β-Blockers successfully reduce cardiac events by reducing these triggers and substrates; however, these effects are less marked in LQTS2 compared with LQTS1. In LQTS3, clinical and experimental investigations of the effects of sympathetic stimulation and β-blocker use have produced contradictory findings, resulting in significant clinical uncertainty. We offer explanations for these contradicting results relating to study sample size, the dose of the β-blocker administered associated with its off-target Na+ channel effects, as well as the type of β-blocker used. We conclude that the antiarrhythmic efficacy of β-blockers is a genotype-specific phenomenon, and hence the use of β-blockers in clinical practice should be genotype dependent.
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Affiliation(s)
- Khalil Saadeh
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom.,School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Kalyanam Shivkumar
- UCLA Cardiac Arrhythmia Centre, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California
| | - Kamalan Jeevaratnam
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
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Zhang X, Pan L, Wei C, Tong R, Li Y, Ding M, Wang H. Crustacean hyperglycemic hormone (CHH) regulates the ammonia excretion and metabolism in white shrimp, Litopenaeus vannamei under ammonia-N stress. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 723:138128. [PMID: 32222513 DOI: 10.1016/j.scitotenv.2020.138128] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 03/20/2020] [Accepted: 03/20/2020] [Indexed: 05/21/2023]
Abstract
To understand the adaptation of Litopenaeus vannamei to high environmental ammonia-N, RNA interference was used to investigate the function of crustacean hyperglycemic hormone (CHH) in the physiological process of neuroendocrine signaling transduction, and ammonia excretion and metabolism. The shrimp were exposed to 25 mg/L NH4Cl and injected with 20 μg/shrimp CHH dsRNA for 72 h. The results showed that hemolymph ammonia content increased under ammonia-N stress and further increased after CHH knockdown, suggesting that CHH can promote ammonia excretion. Moreover, after CHH knockdown, the levels of CHH, DA, and Wnts decreased significantly, the expression of receptor GC, DA1R, Frizzled and LRP 5/6 also decreased, while DA4R increased remarkably. Moreover, PKA and PKG decreased, while PKC markedly increased, and nuclear transcription factors (CREB and TCF) as well as effector proteins (β-catenin, FXYD2, and 14-3-3) were significantly downregulated. Furthermore, ammonia transporters Na+/K+-ATPase (NKA), K+channel, Rh protein, AQP, V-ATPase, and VAMP decreased significantly, while Na+/H+ exchangers (NHE) and Na+/K+/2Cl- cotransporter (NKCC) increased significantly. These results suggest that CHH regulates ammonia excretion in three ways: 1) by mainly regulating ion channels via PKA, PKC, and PKG signaling pathways; 2) by activating related proteins primarily through Wnt signaling pathway; and 3) by exocytosis, mostly induced by the PKA signaling pathway. In addition, the levels of Gln, uric acid, and urea increased in accordance with the activities of GDH/GS, XDH, and arginase, respectively, suggesting that ammonia excretion was inhibited but ammonia metabolism was slightly enhanced. This study deepens our understanding of the mechanism by which crustaceans respond to high environmental ammonia-N.
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Affiliation(s)
- Xin Zhang
- The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, PR China
| | - Luqing Pan
- The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, PR China.
| | - Cun Wei
- The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, PR China
| | - Ruixue Tong
- The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, PR China
| | - Yufen Li
- The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, PR China
| | - Min Ding
- The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, PR China
| | - Hongdan Wang
- The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, PR China
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15
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AKAP5 anchors PKA to enhance regulation of the HERG channel. Int J Biochem Cell Biol 2020; 122:105741. [PMID: 32173522 DOI: 10.1016/j.biocel.2020.105741] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Revised: 02/24/2020] [Accepted: 03/11/2020] [Indexed: 11/21/2022]
Abstract
The activation of the β-adrenergic receptor (β-AR) regulates the human ether a-go-go-related gene (HERG) channel via protein kinase A (PKA), which in turn induces lethal arrhythmia in patients with long QT syndromes (LQTS). However, the role of A-kinase anchoring proteins (AKAPs) in PKA's regulation of the HERG channel and its molecular mechanism are not clear. Here, HEK293 cells were transfected with the HERG gene alone or co-transfected with HERG and AKAP5 using Lipofectamine 2000. Western blotting was performed to determine HERG protein expression, and immunofluorescence and immunoprecipitation were used to assess the binding and cellular colocalization of HERG, AKAP5, and PKA. The HEK293-HERG and HEK293-HERG + AKAP5 cells were treated with forskolin at different concentrations and different time. HERG protein expression significantly increased under all treatment conditions (P < 0.001). The level of HERG protein expression in HEK293-HERG + AKAP5 cells was higher than that observed in HEK293-HERG cells (P < 0.001). Immunofluorescence and immunoprecipitation indicated that HERG bound to PKA and AKAP5 and was colocalized at the cell membrane. The HERG channel protein, AKAP5, and PKA interacted with each other and appeared to form intracellular complexes. These results provide evidence for a novel mechanism which AKAP5 anchors PKA to up-regulate the HERG channel protein.
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16
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Identification of Aberrantly Expressed lncRNAs Involved in Orthodontic Force Using a Subpathway Strategy. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2019; 2019:9250129. [PMID: 31565070 PMCID: PMC6745140 DOI: 10.1155/2019/9250129] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 07/07/2019] [Indexed: 01/25/2023]
Abstract
Background The aim of the study was to identify key long noncoding RNAs (lncRNA) and related subpathways in the periodontal ligament tissue following orthodontic force. Methods We adopt a novelty subpathway strategy to identify lncRNAs competitively regulated functions and the key competitive lncRNAs in periodontal ligament disorders after undergoing orthodontic force. To begin with, patients with orthodontics in our hospital were enrolled in our research. The relationship of lncRNA-mRNA was established through shared predicted miRNA by using the hypergeometric test, Jaccard coefficient standardization, and the Pearson coefficient to determine the valid interaction relationship. After embedding screened lncRNA interactions to pathways, the significant subpathways were recognized by lenient distance and Wallenius approximation methods to calculate the false discovery rate value of each subpathway. Results The lncRNA-mRNA intersections including 263 lncRNAs, 1,599 mRNAs, and 3,762 interacting pairs were obtained. The enriched mRNAs were further enriched into various candidate pathways such as the PI3K-Akt signaling pathway. Several subpathways were screened, including the PI3K-Akt signaling pathway, 04510_1 focal adhesion, and p53 signaling pathway, respectively. The network of pathway-lncRNA-mRNA was constructed. Several key lncRNAs including DNAJC3-AS1, WDFY3-AS2, LINC00482, and DLEU2 were screened. Conclusions DNAJC3-AS1, WDFY3-AS2, LINC00482, and DLEU2 as aberrantly expressed lncRNAs involved in orthodontic force might play crucial roles in periodontal ligament disease pathogenesis.
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17
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Si L, Pan L, Zhang X, Wang H, Wei C. Evidence that dopamine is involved in neuroendocrine regulation, gill intracellular signaling pathways and ion regulation in Litopenaeus vannamei. J Exp Biol 2019; 222:jeb.204073. [DOI: 10.1242/jeb.204073] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 06/27/2019] [Indexed: 01/24/2023]
Abstract
The transport of ions and ammonia in the gills may be regulated by neuroendocrine factors, in order to explore the regulation mechanism of dopamine (DA), hemolymph neuroendocrine hormones, gill intracellular signaling pathways, ion and ammonia transporters, as well as hemolymph osmolality and ammonia concentration were investigated in Litopenaeus vannamei after 10−7 and 10−6 mol shrimp−1 DA injection. The data displayed a significant increase in crustacean hyperglycemic hormone (CHH) concentration at 1-12 h and a transient significant decrease in corticotrophin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH) and cortisol concentrations under DA stimulation. The up-regulation of guanylyl cyclase (GC) mRNA, cyclic guanosine monophosphate (cGMP) and protein kinase G (PKG) concentrations, together with down-regulation of DA receptor D4 mRNA and up-regulation of cyclic adenosine monophosphate (cAMP), protein kinase A (PKA), diacylglycerol (DAG) and protein kinase C (PKC) concentrations suggested an activation of complicated intracellular signaling pathway. The expression of cyclic AMP response element-binding protein (CREB), FXYD2 and 14-3-3 protein mRNA was significantly increased by PKA regulation. The increase in Na+/K+-ATPase (NKA) activity and the stabilization of V-type H+-ATPase (V-ATPase) activity are accompanied by an up-regulation of K+-channel, Na+/K+/2Cl− cotransporter (NKCC), Rh protein and vesicle associated membrane protein (VAMP) mRNA, resulting in an increase in hemolymph osmolality and a decrease in hemolymph ammonia concentration. These results suggest that DA stimulates the secretion of CHH and inhibits the release of cortisol, which activates intracellular signaling factors to facilitate ion and ammonia transport across the gills, and may not affect intracellular acidification.
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Affiliation(s)
- Lingjun Si
- Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao 266003, PR China
| | - Luqing Pan
- Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao 266003, PR China
| | - Xin Zhang
- Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao 266003, PR China
| | - Hongdan Wang
- Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao 266003, PR China
| | - Cun Wei
- Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao 266003, PR China
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18
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Si L, Pan L, Wang H, Zhang X. Ammonia-N exposure alters neurohormone levels in the hemolymph and mRNA abundance of neurohormone receptors and associated downstream factors in the gills of Litopenaeus vannamei. J Exp Biol 2019; 222:jeb.200204. [DOI: 10.1242/jeb.200204] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 04/10/2019] [Indexed: 12/30/2022]
Abstract
Effects of ammonia-N (0.05, 2, 10 and 20 mg L−1) on the neuroendocrine regulation of ammonia transport were investigated in Litopenaeus vannamei. The results showed that corticotrophin-releasing hormone, adrenocorticotropic hormone, dopamine, noradrenaline and 5-hydroxytryptamine concentration in all ammonia-N groups increased significantly between 3-12 h. Cortisol increased significantly between 3-24 h. All hormones except crustacean hyperglycemic hormone were reduced to control levels. mRNA abundance of guanylyl cyclase increased significantly during the experiment. Dopamine receptor D4 and α2 adrenergic receptor mRNA abundance in treatments decreased significantly at the beginning, and eventually returned to the control level, whereas mRNA abundance of 5-HT7 receptor increased significantly only within the first 12 h. Changes of protein kinases (PKA, PKG) mRNA abundance were similar to the patterns of biogenic amines and crustacean hyperglycemic hormone, peaking at 6 h and 12 h respectively, while PKC decreased within 24 h. 14-3-3 protein, FXYD2 and cAMP-response element binding protein mRNA abundance of treatments increased significantly and peaked at 6 h. β-catenin and T-cell factor mRNA abundance increased significantly throughout the experiment and peaked at 12 h. The up-regulation of Rh protein, K+-channel, Na+/K+-ATPase, V-type H+-ATPase and vesicle associated membrane protein (VAMP) mRNA, together with down-regulation of Na+/K+/2Cl− cotransporter mRNA indicated an adjustment of general branchial ion-/ammonia-regulatory mechanisms. Meanwhile, hemolymph ammonia concentration was significantly increased in most ammonia-N exposure groups. Histological investigation revealed the hepatopancreatic damage caused by ammonia-N. The results suggest hormones, biogenic amines and Wnt/β-catenin play a principal role in adapting to ammonia-N exposure and facilitating ammonia transport.
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Affiliation(s)
- Lingjun Si
- Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao 266003, PR China
| | - Luqing Pan
- Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao 266003, PR China
| | - Hongdan Wang
- Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao 266003, PR China
| | - Xin Zhang
- Key Laboratory of Mariculture (Ocean University of China), Ministry of Education, Qingdao 266003, PR China
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19
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Salman OF, El-Rayess HM, Abi Khalil C, Nemer G, Refaat MM. Inherited Cardiomyopathies and the Role of Mutations in Non-coding Regions of the Genome. Front Cardiovasc Med 2018; 5:77. [PMID: 29998127 PMCID: PMC6028572 DOI: 10.3389/fcvm.2018.00077] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 06/04/2018] [Indexed: 01/16/2023] Open
Abstract
Cardiomyopathies (CMs) are a group of cardiac pathologies caused by an intrinsic defect within the myocardium. The relative contribution of genetic mutations in the pathogenesis of certain CMs, such as hypertrophic cardiomyopathy (HCM), arrythmogenic right/left ventricular cardiomyopathy (ARVC) and left ventricular non-compacted cardiomyopathy (LVNC) has been established in comparison to dilated cardiomyopathy (DCM) and restrictive cardiomyopathy (RCM). The aim of this article is to review mutations in the non-coding parts of the genome, namely, microRNA, promoter elements, enhancer/silencer elements, 3′/5′UTRs and introns, that are involved in the pathogenesis CMs. Additionally, we will explore the role of some long non-coding RNAs in the pathogenesis of CMs.
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Affiliation(s)
- Oday F Salman
- Division of Cardiology, Department of Internal Medicine, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Hebah M El-Rayess
- Division of Cardiology, Department of Internal Medicine, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Charbel Abi Khalil
- Department of Genetic Medicine, Weill Cornell Medical College, Doha, Qatar
| | - Georges Nemer
- Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Marwan M Refaat
- Division of Cardiology, Department of Internal Medicine, Faculty of Medicine, American University of Beirut, Beirut, Lebanon.,Department of Biochemistry and Molecular Genetics, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
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20
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Abstract
This study examines the interaction between hERG and Kv4.3. The functional interaction between hERG and Kv4.3, expressed in a heterologous cell line, was studied using patch clamp techniques, western blot, immunofluorescence, and co-immunoprecipitation. Co-expression of Kv4.3 with hERG increased hERG current density (tail current after a step to +10 mV: 26 ± 3 versus 56 ± 7 pA/pF, p < 0.01). Kv4.3 co-expression also increased the protein expression and promoted the membrane localization of hERG. Western blot showed Kv4.3 increased hERG expression by Hsp70. hERG and Kv4.3 co-localized and co-immunoprecipitated in cultured 293 T cells, indicating physical interactions between hERG and Kv4.3 proteins in vitro. In addition, Hsp70 interacted with hERG and Kv4.3 respectively, and formed complexes with hERG and Kv4.3. The α subunit of Ito Kv4.3 can interact with and modify the localization of the α subunit of IKr hERG, thus providing potentially novel insights into the molecular mechanism of the malignant ventricular arrhythmia in heart failure.
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21
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Utrilla RG, Nieto-Marín P, Alfayate S, Tinaquero D, Matamoros M, Pérez-Hernández M, Sacristán S, Ondo L, de Andrés R, Díez-Guerra FJ, Tamargo J, Delpón E, Caballero R. Kir2.1-Nav1.5 Channel Complexes Are Differently Regulated than Kir2.1 and Nav1.5 Channels Alone. Front Physiol 2017; 8:903. [PMID: 29184507 PMCID: PMC5694551 DOI: 10.3389/fphys.2017.00903] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 10/25/2017] [Indexed: 12/27/2022] Open
Abstract
Cardiac Kir2.1 and Nav1.5 channels generate the inward rectifier K+ (IK1) and the Na+ (INa) currents, respectively. There is a mutual interplay between the ventricular INa and IK1 densities, because Nav1.5 and Kir2.1 channels exhibit positive reciprocal modulation. Here we compared some of the biological properties of Nav1.5 and Kir2.1 channels when they are expressed together or separately to get further insights regarding their putative interaction. First we demonstrated by proximity ligation assays (PLAs) that in the membrane of ventricular myocytes Nav1.5 and Kir2.1 proteins are in close proximity to each other (<40 nm apart). Furthermore, intracellular dialysis with anti-Nav1.5 and anti-Kir2.1 antibodies suggested that these channels form complexes. Patch-clamp experiments in heterologous transfection systems demonstrated that the inhibition of the Ca2+/calmodulin-dependent protein kinase II (CaMKII) decreased the INa and the IK1 generated by Nav1.5 and Kir2.1 channels when they were coexpressed, but not the IK1 generated by Kir2.1 channels alone, suggesting that complexes, but not Kir2.1 channels, are a substrate of CaMKII. Furthermore, inhibition of CaMKII precluded the interaction between Nav1.5 and Kir2.1 channels. Inhibition of 14-3-3 proteins did not modify the INa and IK1 densities generated by each channel separately, whereas it decreased the INa and IK1 generated when they were coexpressed. However, inhibition of 14-3-3 proteins did not abolish the Nav1.5-Kir2.1 interaction. Inhibition of dynamin-dependent endocytosis reduced the internalization of Kir2.1 but not of Nav1.5 or Kir2.1-Nav1.5 complexes. Inhibition of cytoskeleton-dependent vesicular trafficking via the dynein/dynactin motor increased the IK1, but reduced the INa, thus suggesting that the dynein/dynactin motor is preferentially involved in the backward and forward traffic of Kir2.1 and Nav1.5, respectively. Conversely, the dynein/dynactin motor participated in the forward movement of Kir2.1-Nav1.5 complexes. Ubiquitination by Nedd4-2 ubiquitin-protein ligase promoted the Nav1.5 degradation by the proteasome, but not that of Kir2.1 channels. Importantly, the Kir2.1-Nav1.5 complexes were degraded following this route as demonstrated by the overexpression of Nedd4-2 and the inhibition of the proteasome with MG132. These results suggested that Kir2.1 and Nav1.5 channels closely interact with each other leading to the formation of a pool of complexed channels whose biology is similar to that of the Nav1.5 channels.
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Affiliation(s)
- Raquel G Utrilla
- Department of Pharmacology, School of Medicine, Instituto de Investigación Sanitaria Gregorio Marañón, Universidad Complutense, Madrid, Spain.,CIBERCV, Madrid, Spain
| | - Paloma Nieto-Marín
- Department of Pharmacology, School of Medicine, Instituto de Investigación Sanitaria Gregorio Marañón, Universidad Complutense, Madrid, Spain.,CIBERCV, Madrid, Spain
| | - Silvia Alfayate
- Department of Pharmacology, School of Medicine, Instituto de Investigación Sanitaria Gregorio Marañón, Universidad Complutense, Madrid, Spain.,CIBERCV, Madrid, Spain
| | - David Tinaquero
- Department of Pharmacology, School of Medicine, Instituto de Investigación Sanitaria Gregorio Marañón, Universidad Complutense, Madrid, Spain.,CIBERCV, Madrid, Spain
| | - Marcos Matamoros
- Department of Pharmacology, School of Medicine, Instituto de Investigación Sanitaria Gregorio Marañón, Universidad Complutense, Madrid, Spain.,CIBERCV, Madrid, Spain
| | - Marta Pérez-Hernández
- Department of Pharmacology, School of Medicine, Instituto de Investigación Sanitaria Gregorio Marañón, Universidad Complutense, Madrid, Spain.,CIBERCV, Madrid, Spain
| | | | - Lorena Ondo
- Department of Pharmacology, School of Medicine, Instituto de Investigación Sanitaria Gregorio Marañón, Universidad Complutense, Madrid, Spain.,CIBERCV, Madrid, Spain
| | - Raquel de Andrés
- Departamento de Biología Molecular and Centro de Biología Molecular "Severo Ochoa" (UAM-CSIC), Universidad Autónoma de Madrid, Madrid, Spain
| | - F Javier Díez-Guerra
- Departamento de Biología Molecular and Centro de Biología Molecular "Severo Ochoa" (UAM-CSIC), Universidad Autónoma de Madrid, Madrid, Spain
| | - Juan Tamargo
- Department of Pharmacology, School of Medicine, Instituto de Investigación Sanitaria Gregorio Marañón, Universidad Complutense, Madrid, Spain.,CIBERCV, Madrid, Spain
| | - Eva Delpón
- Department of Pharmacology, School of Medicine, Instituto de Investigación Sanitaria Gregorio Marañón, Universidad Complutense, Madrid, Spain.,CIBERCV, Madrid, Spain
| | - Ricardo Caballero
- Department of Pharmacology, School of Medicine, Instituto de Investigación Sanitaria Gregorio Marañón, Universidad Complutense, Madrid, Spain.,CIBERCV, Madrid, Spain
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Duncan G, Firth K, George V, Hoang MD, Staniforth A, Smith G, Denning C. Drug-Mediated Shortening of Action Potentials in LQTS2 Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes. Stem Cells Dev 2017; 26:1695-1705. [PMID: 28992755 PMCID: PMC5706629 DOI: 10.1089/scd.2017.0172] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Cardiomyocytes (CMs) derived from human induced pluripotent stem cells (hiPSCs) are now a well-established modality for modeling genetic disorders of the heart. This is especially so for long QT syndrome (LQTS), which is caused by perturbation of ion channel function, and can lead to fainting, malignant arrhythmias and sudden cardiac death. LQTS2 is caused by mutations in KCNH2, a gene whose protein product contributes to IKr (also known as HERG), which is the predominant repolarizing potassium current in CMs. β-blockers are the mainstay treatment for patients with LQTS, functioning by reducing heart rate and arrhythmogenesis. However, they are not effective in around a quarter of LQTS2 patients, in part, because they do not correct the defining feature of the condition, which is excessively prolonged QT interval. Since new therapeutics are needed, in this report, we biopsied skin fibroblasts from a patient who was both genetically and clinically diagnosed with LQTS2. By producing LQTS-hiPSC-CMs, we assessed the impact of different drugs on action potential duration (APD), which is used as an in vitro surrogate for QT interval. Not surprisingly, the patient's own β-blocker medication, propranolol, had a marginal effect on APD in the LQTS-hiPSC-CMs. However, APD could be significantly reduced by up to 19% with compounds that enhanced the IKr current by direct channel binding or by indirect mediation through the PPARδ/protein 14-3-3 epsilon/HERG pathway. Drug-induced enhancement of an alternative potassium current, IKATP, also reduced APD by up to 21%. This study demonstrates the utility of LQTS-hiPSC-CMs in evaluating whether drugs can shorten APD and, importantly, shows that PPARδ agonists may form a new class of therapeutics for this condition.
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Affiliation(s)
- Gary Duncan
- 1 Department of Stem Cell Biology, Centre of Biomolecular Sciences, University of Nottingham , Nottingham, United Kingdom
| | - Karl Firth
- 1 Department of Stem Cell Biology, Centre of Biomolecular Sciences, University of Nottingham , Nottingham, United Kingdom
| | - Vinoj George
- 1 Department of Stem Cell Biology, Centre of Biomolecular Sciences, University of Nottingham , Nottingham, United Kingdom .,2 Guy Hilton Research Centre, Institute for Science and Technology in Medicine (ISTM), Keele University , Staffordshire, United Kingdom
| | - Minh Duc Hoang
- 1 Department of Stem Cell Biology, Centre of Biomolecular Sciences, University of Nottingham , Nottingham, United Kingdom .,2 Guy Hilton Research Centre, Institute for Science and Technology in Medicine (ISTM), Keele University , Staffordshire, United Kingdom
| | - Andrew Staniforth
- 3 Department of Cardiovascular Medicine, Queen's Medical Centre , Nottingham, United Kingdom
| | - Godfrey Smith
- 4 Institute of Cardiovascular and Medical Sciences, University of Glasgow , Glasgow, United Kingdom
| | - Chris Denning
- 1 Department of Stem Cell Biology, Centre of Biomolecular Sciences, University of Nottingham , Nottingham, United Kingdom
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Habecker BA, Anderson ME, Birren SJ, Fukuda K, Herring N, Hoover DB, Kanazawa H, Paterson DJ, Ripplinger CM. Molecular and cellular neurocardiology: development, and cellular and molecular adaptations to heart disease. J Physiol 2016; 594:3853-75. [PMID: 27060296 DOI: 10.1113/jp271840] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 03/15/2016] [Indexed: 12/12/2022] Open
Abstract
The nervous system and cardiovascular system develop in concert and are functionally interconnected in both health and disease. This white paper focuses on the cellular and molecular mechanisms that underlie neural-cardiac interactions during development, during normal physiological function in the mature system, and during pathological remodelling in cardiovascular disease. The content on each subject was contributed by experts, and we hope that this will provide a useful resource for newcomers to neurocardiology as well as aficionados.
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Affiliation(s)
- Beth A Habecker
- Department of Physiology and Pharmacology, Department of Medicine Division of Cardiovascular Medicine and Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, 97239, USA
| | - Mark E Anderson
- Johns Hopkins Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, 21287, USA
| | - Susan J Birren
- Department of Biology, Volen Center for Complex Systems, Brandeis University, Waltham, MA, 02453, USA
| | - Keiichi Fukuda
- Department of Cardiology, Keio University School of Medicine, 35-Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Neil Herring
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford, OX1 3PT, UK
| | - Donald B Hoover
- Department of Biomedical Sciences, Center of Excellence in Inflammation, Infectious Disease and Immunity, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN, 37614, USA
| | - Hideaki Kanazawa
- Department of Cardiology, Keio University School of Medicine, 35-Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - David J Paterson
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford, OX1 3PT, UK
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24
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Gardner RT, Ripplinger CM, Myles RC, Habecker BA. Molecular Mechanisms of Sympathetic Remodeling and Arrhythmias. Circ Arrhythm Electrophysiol 2016; 9:e001359. [PMID: 26810594 DOI: 10.1161/circep.115.001359] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Ryan T Gardner
- From the Department of Physiology and Pharmacology and Knight Cardiovascular Institute, Oregon Health and Science University, Portland (R.T.G., B.A.H.); Department of Pharmacology, School of Medicine, University of California, Davis (C.M.R.); and Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom (R.C.M.)
| | - Crystal M Ripplinger
- From the Department of Physiology and Pharmacology and Knight Cardiovascular Institute, Oregon Health and Science University, Portland (R.T.G., B.A.H.); Department of Pharmacology, School of Medicine, University of California, Davis (C.M.R.); and Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom (R.C.M.)
| | - Rachel C Myles
- From the Department of Physiology and Pharmacology and Knight Cardiovascular Institute, Oregon Health and Science University, Portland (R.T.G., B.A.H.); Department of Pharmacology, School of Medicine, University of California, Davis (C.M.R.); and Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom (R.C.M.)
| | - Beth A Habecker
- From the Department of Physiology and Pharmacology and Knight Cardiovascular Institute, Oregon Health and Science University, Portland (R.T.G., B.A.H.); Department of Pharmacology, School of Medicine, University of California, Davis (C.M.R.); and Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom (R.C.M.).
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25
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Ripplinger CM, Noujaim SF, Linz D. The nervous heart. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2016; 120:199-209. [PMID: 26780507 DOI: 10.1016/j.pbiomolbio.2015.12.015] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 12/29/2015] [Accepted: 12/31/2015] [Indexed: 12/23/2022]
Abstract
Many cardiac electrophysiological abnormalities are accompanied by autonomic nervous system dysfunction. Here, we review mechanisms by which the cardiac nervous system controls normal and abnormal excitability and may contribute to atrial and ventricular tachyarrhythmias. Moreover, we explore the potential antiarrhythmic and/or arrhythmogenic effects of modulating the autonomic nervous system by several strategies, including ganglionated plexi ablation, vagal and spinal cord stimulations, and renal sympathetic denervation as therapies for atrial and ventricular arrhythmias.
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Affiliation(s)
- Crystal M Ripplinger
- Department of Pharmacology, University of California Davis, 451 Health Sciences Drive, Davis, CA 95616, USA.
| | - Sami F Noujaim
- Molecular Pharmacology and Physiology, University of South Florida, 12901 Bruce B Downs Blvd, Tampa, FL 33612, USA.
| | - Dominik Linz
- Klinik für Innere Medizin III, Universitätsklinikum des Saarlandes, 66421 Homburg, Saar, Germany.
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26
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Kilisch M, Lytovchenko O, Arakel EC, Bertinetti D, Schwappach B. A dual phosphorylation switch controls 14-3-3-dependent cell surface expression of TASK-1. J Cell Sci 2016; 129:831-42. [PMID: 26743085 PMCID: PMC4760375 DOI: 10.1242/jcs.180182] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 12/29/2015] [Indexed: 11/20/2022] Open
Abstract
The transport of the K+ channels TASK-1 and TASK-3 (also known as KCNK3 and KCNK9, respectively) to the cell surface is controlled by the binding of 14-3-3 proteins to a trafficking control region at the extreme C-terminus of the channels. The current model proposes that phosphorylation-dependent binding of 14-3-3 sterically masks a COPI-binding motif. However, the direct effects of phosphorylation on COPI binding and on the binding parameters of 14-3-3 isoforms are still unknown. We find that phosphorylation of the trafficking control region prevents COPI binding even in the absence of 14-3-3, and we present a quantitative analysis of the binding of all human 14-3-3 isoforms to the trafficking control regions of TASK-1 and TASK-3. Surprisingly, the affinities of 14-3-3 proteins for TASK-1 are two orders of magnitude lower than for TASK-3. Furthermore, we find that phosphorylation of a second serine residue in the C-terminus of TASK-1 inhibits 14-3-3 binding. Thus, phosphorylation of the trafficking control region can stimulate or inhibit transport of TASK-1 to the cell surface depending on the target serine residue. Our findings indicate that control of TASK-1 trafficking by COPI, kinases, phosphatases and 14-3-3 proteins is highly dynamic. Summary: Phosphorylation of a previously neglected serine residue in the trafficking control region of TASK-1 interferes with the binding of trafficking machinery and enables complex regulation by physiological stimuli.
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Affiliation(s)
- Markus Kilisch
- Department of Molecular Biology, Universitätsmedizin Göttingen, Humboldtallee 23, Göttingen 37073, Germany
| | - Olga Lytovchenko
- Department of Molecular Biology, Universitätsmedizin Göttingen, Humboldtallee 23, Göttingen 37073, Germany
| | - Eric C Arakel
- Department of Molecular Biology, Universitätsmedizin Göttingen, Humboldtallee 23, Göttingen 37073, Germany
| | | | - Blanche Schwappach
- Department of Molecular Biology, Universitätsmedizin Göttingen, Humboldtallee 23, Göttingen 37073, Germany Max-Planck Institute for Biophysical Chemistry, Göttingen 37077, Germany
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27
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Abriel H, Rougier JS, Jalife J. Ion channel macromolecular complexes in cardiomyocytes: roles in sudden cardiac death. Circ Res 2015; 116:1971-88. [PMID: 26044251 DOI: 10.1161/circresaha.116.305017] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The movement of ions across specific channels embedded on the membrane of individual cardiomyocytes is crucial for the generation and propagation of the cardiac electric impulse. Emerging evidence over the past 20 years strongly suggests that the normal electric function of the heart is the result of dynamic interactions of membrane ion channels working in an orchestrated fashion as part of complex molecular networks. Such networks work together with exquisite temporal precision to generate each action potential and contraction. Macromolecular complexes play crucial roles in transcription, translation, oligomerization, trafficking, membrane retention, glycosylation, post-translational modification, turnover, function, and degradation of all cardiac ion channels known to date. In addition, the accurate timing of each cardiac beat and contraction demands, a comparable precision on the assembly and organizations of sodium, calcium, and potassium channel complexes within specific subcellular microdomains, where physical proximity allows for prompt and efficient interaction. This review article, part of the Compendium on Sudden Cardiac Death, discusses the major issues related to the role of ion channel macromolecular assemblies in normal cardiac electric function and the mechanisms of arrhythmias leading to sudden cardiac death. It provides an idea of how these issues are being addressed in the laboratory and in the clinic, which important questions remain unanswered, and what future research will be needed to improve knowledge and advance therapy.
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Affiliation(s)
- Hugues Abriel
- From the Department of Clinical Research, University of Bern, Bern, Switzerland (H.A., J.-S.R.); Center for Arrhythmia Research, Department of Internal Medicine, University of Michigan, Ann Arbor (J.J.); and Area of Myocardial Pathophysiology, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain (J.J.)
| | - Jean-Sébastien Rougier
- From the Department of Clinical Research, University of Bern, Bern, Switzerland (H.A., J.-S.R.); Center for Arrhythmia Research, Department of Internal Medicine, University of Michigan, Ann Arbor (J.J.); and Area of Myocardial Pathophysiology, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain (J.J.)
| | - José Jalife
- From the Department of Clinical Research, University of Bern, Bern, Switzerland (H.A., J.-S.R.); Center for Arrhythmia Research, Department of Internal Medicine, University of Michigan, Ann Arbor (J.J.); and Area of Myocardial Pathophysiology, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain (J.J.).
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28
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Feng X, Li Z, Du Y, Fu H, Klein JD, Cai H, Sands JM, Chen G. Downregulation of urea transporter UT-A1 activity by 14-3-3 protein. Am J Physiol Renal Physiol 2015; 309:F71-8. [PMID: 25995111 PMCID: PMC4490382 DOI: 10.1152/ajprenal.00546.2014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 05/13/2015] [Indexed: 11/22/2022] Open
Abstract
Urea transporter (UT)-A1 in the kidney inner medulla plays a critical role in the urinary concentrating mechanism and thereby in the regulation of water balance. The 14-3-3 proteins are a family of seven isoforms. They are multifunctional regulatory proteins that mainly bind to phosphorylated serine/threonine residues in target proteins. In the present study, we found that all seven 14-3-3 isoforms were detected in the kidney inner medulla. However, only the 14-3-3 γ-isoform was specifically and highly associated with UT-A1, as demonstrated by a glutathione-S-transferase-14-3-3 pulldown assay. The cAMP/adenylyl cyclase stimulator forskolin significantly enhanced their binding. Coinjection of 14-3-3γ cRNA into oocytes resulted in a decrease of UT-A1 function. In addition, 14-3-3γ increased UT-A1 ubiquitination and protein degradation. 14-3-3γ can interact with both UT-A1 and mouse double minute 2, the E3 ubiquitin ligase for UT-A1. Thus, activation of cAMP/PKA increases 14-3-3γ interactions with UT-A1 and stimulates mouse double minute 2-mediated UT-A1 ubiquitination and degradation, thereby forming a novel regulatory mechanism of urea transport activity.
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Affiliation(s)
- Xiuyan Feng
- Renal Division, Department of Medicine, Emory University, School of Medicine, Atlanta, Georgia; Section of Nephrology, Atlanta Veterans Administration Medical Center, Decatur, Georgia
| | - Zenggang Li
- Department of Pharmacology, Emory University, School of Medicine, Atlanta, Georgia
| | - Yuhong Du
- Department of Pharmacology, Emory University, School of Medicine, Atlanta, Georgia
| | - Haian Fu
- Department of Pharmacology, Emory University, School of Medicine, Atlanta, Georgia
| | - Janet D Klein
- Renal Division, Department of Medicine, Emory University, School of Medicine, Atlanta, Georgia; Department of Physiology, Emory University, School of Medicine, Atlanta, Georgia; and
| | - Hui Cai
- Renal Division, Department of Medicine, Emory University, School of Medicine, Atlanta, Georgia; Department of Physiology, Emory University, School of Medicine, Atlanta, Georgia; and Section of Nephrology, Atlanta Veterans Administration Medical Center, Decatur, Georgia
| | - Jeff M Sands
- Renal Division, Department of Medicine, Emory University, School of Medicine, Atlanta, Georgia; Department of Physiology, Emory University, School of Medicine, Atlanta, Georgia; and
| | - Guangping Chen
- Renal Division, Department of Medicine, Emory University, School of Medicine, Atlanta, Georgia; Department of Physiology, Emory University, School of Medicine, Atlanta, Georgia; and
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29
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Carretero L, Llavona P, López-Hernández A, Casado P, Cutillas PR, de la Peña P, Barros F, Domínguez P. ERK and RSK are necessary for TRH-induced inhibition of r-ERG potassium currents in rat pituitary GH3 cells. Cell Signal 2015; 27:1720-30. [PMID: 26022182 DOI: 10.1016/j.cellsig.2015.05.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 05/04/2015] [Accepted: 05/20/2015] [Indexed: 11/16/2022]
Abstract
The transduction pathway mediating the inhibitory effect that TRH exerts on r-ERG channels has been thoroughly studied in GH3 rat pituitary cells but some elements have yet to be discovered, including those involved in a phosphorylation event(s). Using a quantitative phosphoproteomic approach we studied the changes in phosphorylation caused by treatment with 1μM TRH for 5min in GH3 cells. The activating residues of Erk2 and Erk1 undergo phosphorylation increases of 5.26 and 4.87 fold, respectively, in agreement with previous reports of ERK activation by TRH in GH3 cells. Thus, we studied the possible involvement of ERK pathway in the signal transduction from TRH receptor to r-ERG channels. The MEK inhibitor U0126 at 0.5μM caused no major blockade of the basal r-ERG current, but impaired the TRH inhibitory effect on r-ERG. Indeed, the TRH effect on r-ERG was also reduced when GH3 cells were transfected with siRNAs against either Erk1 or Erk2. Using antibodies, we found that TRH treatment also causes activating phosphorylation of Rsk. The TRH effect on r-ERG current was also impaired when cells were transfected with any of two different siRNAs mixtures against Rsk1. However, treatment of GH3 cells with 20nM EGF for 5min, which causes ERK and RSK activation, had no effect on the r-ERG currents. Therefore, we conclude that in the native GH3 cell system, ERK and RSK are involved in the pathway linking TRH receptor to r-ERG channel inhibition, but additional components must participate to cause such inhibition.
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Affiliation(s)
- Luis Carretero
- Departamento de Bioquímica y Biología Molecular, Edificio Santiago Gascón, Campus de El Cristo, Universidad de Oviedo, 33006 Oviedo, Spain
| | - Pablo Llavona
- Departamento de Bioquímica y Biología Molecular, Edificio Santiago Gascón, Campus de El Cristo, Universidad de Oviedo, 33006 Oviedo, Spain
| | - Alejandro López-Hernández
- Departamento de Bioquímica y Biología Molecular, Edificio Santiago Gascón, Campus de El Cristo, Universidad de Oviedo, 33006 Oviedo, Spain
| | - Pedro Casado
- Integrative Cell Signalling and Proteomics, Centre for Haemato-Oncology, Barts Cancer Institute, Queen Mary University of London, Barts School of Medicine and Dentistry, London EC1M 6BQ, United Kingdom
| | - Pedro R Cutillas
- Integrative Cell Signalling and Proteomics, Centre for Haemato-Oncology, Barts Cancer Institute, Queen Mary University of London, Barts School of Medicine and Dentistry, London EC1M 6BQ, United Kingdom
| | - Pilar de la Peña
- Departamento de Bioquímica y Biología Molecular, Edificio Santiago Gascón, Campus de El Cristo, Universidad de Oviedo, 33006 Oviedo, Spain
| | - Francisco Barros
- Departamento de Bioquímica y Biología Molecular, Edificio Santiago Gascón, Campus de El Cristo, Universidad de Oviedo, 33006 Oviedo, Spain
| | - Pedro Domínguez
- Departamento de Bioquímica y Biología Molecular, Edificio Santiago Gascón, Campus de El Cristo, Universidad de Oviedo, 33006 Oviedo, Spain.
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30
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Liu F, Zhou Q, Zhou J, Sun H, Wang Y, Zou X, Feng L, Hou Z, Zhou A, Zhou Y, Li Y. 14-3-3τ promotes surface expression of Cav2.2 (α1B) Ca2+ channels. J Biol Chem 2014; 290:2689-98. [PMID: 25516596 DOI: 10.1074/jbc.m114.567800] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Surface expression of voltage-gated Ca(2+) (Cav) channels is important for their function in calcium homeostasis in the physiology of excitable cells, but whether or not and how the α1 pore-forming subunits of Cav channels are trafficked to plasma membrane in the absence of the known Cav auxiliary subunits, β and α2δ, remains mysterious. Here we showed that 14-3-3 proteins promoted functional surface expression of the Cav2.2 α1B channel in transfected tsA-201 cells in the absence of any known Cav auxiliary subunit. Both the surface to total ratio of the expressed α1B protein and the current density of voltage step-evoked Ba(2+) current were markedly suppressed by the coexpression of a 14-3-3 antagonist construct, pSCM138, but not its inactive control, pSCM174, as determined by immunofluorescence assay and whole cell voltage clamp recording, respectively. By contrast, coexpression with 14-3-3τ significantly enhanced the surface expression and current density of the Cav2.2 α1B channel. Importantly, we found that between the two previously identified 14-3-3 binding regions at the α1B C terminus, only the proximal region (amino acids 1706-1940), closer to the end of the last transmembrane domain, was retained by the endoplasmic reticulum and facilitated by 14-3-3 to traffic to plasma membrane. Additionally, we showed that the 14-3-3/Cav β subunit coregulated the surface expression of Cav2.2 channels in transfected tsA-201 cells and neurons. Altogether, our findings reveal a previously unidentified regulatory function of 14-3-3 proteins in promoting the surface expression of Cav2.2 α1B channels.
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Affiliation(s)
- Feng Liu
- From the Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China and
| | - Qin Zhou
- From the Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China and
| | - Jie Zhou
- From the Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China and
| | - Hao Sun
- From the Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China and
| | - Yan Wang
- From the Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China and
| | - Xiuqun Zou
- From the Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China and
| | - Lingling Feng
- From the Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China and
| | - Zhaoyuan Hou
- From the Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China and
| | - Aiwu Zhou
- From the Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China and
| | - Yi Zhou
- the Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida 32306
| | - Yong Li
- From the Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China and
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Depletion of 14-3-3γ reduces the surface expression of Transient Receptor Potential Melastatin 4b (TRPM4b) channels and attenuates TRPM4b-mediated glutamate-induced neuronal cell death. Mol Brain 2014; 7:52. [PMID: 25047048 PMCID: PMC4115172 DOI: 10.1186/s13041-014-0052-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 07/14/2014] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND TRPM4 channels are Ca2+-activated nonselective cation channels which are deeply involved in physiological and pathological conditions. However, their trafficking mechanism and binding partners are still elusive. RESULTS We have found the 14-3-3γ as a binding partner for TRPM4b using its N-terminal fragment from the yeast-two hybrid screening. Ser88 at the N-terminus of TRPM4b is critical for 14-3-3γ binding by showing GST pull-down and co-immunoprecipitation. Heterologous overexpression of 14-3-3γ in HEK293T cells increased TRPM4b expression on the plasma membrane which was measured by whole-cell recordings and cell surface biotinylation experiment. Surface expression of TRPM4b was greatly reduced by short hairpin RNA (shRNA) against 14-3-3γ. Next, endogenous TRPM4b-mediated currents were electrophysiologically characterized by application of glutamate and 9-phenanthrol, a TRPM4b specific antagonist in HT-22 cells which originated from mouse hippocampal neurons. Glutamate-induced TRPM4b currents were significantly attenuated by shRNAs against 14-3-3γ or TRPM4b in these cells. Finally, glutamate-induced cell death was greatly prevented by treatment of 9-phenanthrol or 14-3-3γ shRNA. CONCLUSION These results showed that the cell surface expression of TRPM4 channels is mediated by 14-3-3γ binding, and the specific inhibition of this trafficking process can be a potential therapeutic target for glutamate-induced neuronal cell death.
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Ouadid-Ahidouch H, Ahidouch A. K(+) channels and cell cycle progression in tumor cells. Front Physiol 2013; 4:220. [PMID: 23970866 PMCID: PMC3747328 DOI: 10.3389/fphys.2013.00220] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 07/31/2013] [Indexed: 11/24/2022] Open
Abstract
K+ ions play a major role in many cellular processes. The deregulation of K+ signaling is associated with a variety of diseases such as hypertension, atherosclerosis, or diabetes. K+ ions are important for setting the membrane potential, the driving force for Ca2+ influx, and regulate volume of growing cells. Moreover, it is increasingly recognized that K+ channels control cell proliferation through a novel signaling mechanisms triggered and modulated independently of ion fluxes. In cancer, aberrant expression, regulation and/or sublocalization of K+ channels can alter the downstream signals that converge on the cell cycle machinery. Various K+ channels are involved in cell cycle progression and are needed only at particular stages of the cell cycle. Consistent with this idea, the expression of Eag1 and HERG channels fluctuate along the cell cycle. Despite of acquired knowledge, our understanding of K+ channels functioning in cancer cells requires further studies. These include identifying the molecular mechanisms controlling the cell cycle machinery. By understanding how K+ channels regulate cell cycle progression in cancer cells, we will gain insights into how cancer cells subvert the need for K+ signal and its downstream targets to proliferate.
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Affiliation(s)
- Halima Ouadid-Ahidouch
- Laboratory of Cellular and Molecular Physiology EA4667, SFR CAP-SANTE FED 4231, UFR Sciences, University of Picardie Jules Verne Amiens, France
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Hayashi M, Novak I. Molecular basis of potassium channels in pancreatic duct epithelial cells. Channels (Austin) 2013; 7:432-41. [PMID: 23962792 PMCID: PMC4042478 DOI: 10.4161/chan.26100] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Potassium channels regulate excitability, epithelial ion transport, proliferation, and apoptosis. In pancreatic ducts, K+ channels hyperpolarize the membrane potential and provide the driving force for anion secretion. This review focuses on the molecular candidates of functional K+ channels in pancreatic duct cells, including KCNN4 (KCa3.1), KCNMA1 (KCa1.1), KCNQ1 (Kv7.1), KCNH2 (Kv11.1), KCNH5 (Kv10.2), KCNT1 (KCa4.1), KCNT2 (KCa4.2), and KCNK5 (K2P5.1). We will give an overview of K+ channels with respect to their electrophysiological and pharmacological characteristics and regulation, which we know from other cell types, preferably in epithelia, and, where known, their identification and functions in pancreatic ducts and in adenocarcinoma cells. We conclude by pointing out some outstanding questions and future directions in pancreatic K+ channel research with respect to the physiology of secretion and pancreatic pathologies, including pancreatitis, cystic fibrosis, and cancer, in which the dysregulation or altered expression of K+ channels may be of importance.
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Affiliation(s)
- Mikio Hayashi
- Department of Biology; University of Copenhagen; Copenhagen, Denmark
| | - Ivana Novak
- Department of Biology; University of Copenhagen; Copenhagen, Denmark
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34
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Gallego M, Alday A, Alonso H, Casis O. Adrenergic regulation of cardiac ionic channels: role of membrane microdomains in the regulation of kv4 channels. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:692-9. [PMID: 23811359 DOI: 10.1016/j.bbamem.2013.06.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 06/13/2013] [Accepted: 06/17/2013] [Indexed: 11/18/2022]
Abstract
The heart must constantly adapt its activity to the needs of the body. In any potentially dangerous or physically demanding situation the activated sympathetic nervous system leads a very fast cardiac response. Under these circumstances, α1-adrenergic receptors activate intracellular signaling pathways that finally phosphorylate the caveolae-located subpopulation of Kv4 channels and reduce the transient outward K(+) current (Ito) amplitude. This reduction changes the shape of the cardiac action potential and makes the plateau phase to start at higher voltages. This means that there are more calcium ions entering the myocyte and the result is an increase in the strength of the contraction. However, an excessive reduction of Ito could dangerously prolong action potential duration and this could cause arrhythmias when the heart rate is high. This excessive current reduction does not occur because there is a second population of Ito channels located in non-caveolar membrane rafts that are not accessible for α1-AR mediated regulation. Thus, the location of the components of a given transduction signaling pathway in membrane domains determines the correct and safe behavior of the heart. This article is part of a Special Issue entitled: Reciprocal influences between cell cytoskeleton and membrane channels, receptors and transporters. This article is part of a Special Issue entitled: Reciprocal influences between cell cytoskeleton and membrane channels, receptors and transporters. Guest Editor: Jean Claude Hervé.
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Affiliation(s)
- Mónica Gallego
- Lascaray Research Center, University of the Basque Country (UPV/EHU), Av. Miguel de Unamuno 3, 01006 Vitoria, Spain; Departamento de Fisiología, Facultad de Farmacia, University of the Basque Country (UPV/EHU), Paseo de la Universidad 7, 01006 Vitoria, Spain.
| | - Aintzane Alday
- Departamento de Fisiología, Facultad de Farmacia, University of the Basque Country (UPV/EHU), Paseo de la Universidad 7, 01006 Vitoria, Spain.
| | - Hiart Alonso
- Lascaray Research Center, University of the Basque Country (UPV/EHU), Av. Miguel de Unamuno 3, 01006 Vitoria, Spain; Departamento de Fisiología, Facultad de Farmacia, University of the Basque Country (UPV/EHU), Paseo de la Universidad 7, 01006 Vitoria, Spain.
| | - Oscar Casis
- Lascaray Research Center, University of the Basque Country (UPV/EHU), Av. Miguel de Unamuno 3, 01006 Vitoria, Spain; Departamento de Fisiología, Facultad de Farmacia, University of the Basque Country (UPV/EHU), Paseo de la Universidad 7, 01006 Vitoria, Spain.
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35
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Chang B, Gorbea C, Lezin G, Li L, Shan L, Sakai N, Kogaki S, Otomo T, Okinaga T, Hamaoka A, Yu X, Hata Y, Nishida N, Yost HJ, Bowles NE, Brunelli L, Ichida F. 14-3-3ε gene variants in a Japanese patient with left ventricular noncompaction and hypoplasia of the corpus callosum. Gene 2012; 515:173-80. [PMID: 23266643 DOI: 10.1016/j.gene.2012.12.049] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Accepted: 12/02/2012] [Indexed: 01/07/2023]
Abstract
BACKGROUND Left ventricular noncompaction (LVNC) is a cardiomyopathy characterized by a prominent trabecular meshwork and deep intertrabecular recesses, and is thought to be due to an arrest of normal endomyocardial morphogenesis. However, the genes contributing to this process remain poorly understood. 14-3-3ε, encoded by YWHAE, is an adapter protein belonging to the 14-3-3 protein family which plays important roles in neuronal development and is involved in Miller-Dieker syndrome. We recently showed that mice lacking this gene develop LVNC. Therefore, we hypothesized that variants in YWHAE may contribute to the pathophysiology of LVNC in humans. METHODS AND RESULTS In 77 Japanese patients with LVNC, including the probands of 29 families, mutation analysis of YWHAE by direct DNA sequencing identified 7 novel variants. One of them, c.-458G>T, in the YWHAE promoter, was identified in a familial patient with LVNC and hypoplasia of the corpus callosum. The -458G>T variant is located within a regulatory CCAAT/enhancer binding protein (C/EBP) response element of the YWHAE promoter, and it reduced promoter activity by approximately 50%. Increased binding of an inhibitory C/EBPβ isoform was implicated in decreasing YWHAE promoter activity. Interestingly, we had previously shown that C/EBPβ is a key regulator of YWHAE. CONCLUSIONS These data suggest that the -458G>T YWHAE variant contributes to the abnormal myocardial morphogenesis characteristic of LVNC as well as abnormal brain development, and implicate YWHAE as a novel candidate gene in pediatric cardiomyopathies.
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Affiliation(s)
- Bo Chang
- Department of Pediatrics, University of Toyama, Toyama, Japan
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Hsu PH, Miaw SC, Chuang CC, Chang PY, Fu SJ, Jow GM, Chiu MM, Jeng CJ. 14-3-3θ is a binding partner of rat Eag1 potassium channels. PLoS One 2012; 7:e41203. [PMID: 22911758 PMCID: PMC3401112 DOI: 10.1371/journal.pone.0041203] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Accepted: 06/18/2012] [Indexed: 12/15/2022] Open
Abstract
The ether-à-go-go (Eag) potassium (K(+)) channel belongs to the superfamily of voltage-gated K(+) channel. In mammals, the expression of Eag channels is neuron-specific but their neurophysiological role remains obscure. We have applied the yeast two-hybrid screening system to identify rat Eag1 (rEag1)-interacting proteins from a rat brain cDNA library. One of the clones we identified was 14-3-3θ, which belongs to a family of small acidic protein abundantly expressed in the brain. Data from in vitro yeast two-hybrid and GST pull-down assays suggested that the direct association with 14-3-3θ was mediated by both the N- and the C-termini of rEag1. Co-precipitation of the two proteins was confirmed in both heterologous HEK293T cells and native hippocampal neurons. Electrophysiological studies showed that over-expression of 14-3-3θ led to a sizable suppression of rEag1 K(+) currents with no apparent alteration of the steady-state voltage dependence and gating kinetics. Furthermore, co-expression with 14-3-3θ failed to affect the total protein level, membrane trafficking, and single channel conductance of rEag1, implying that 14-3-3θ binding may render a fraction of the channel locked in a non-conducting state. Together these data suggest that 14-3-3θ is a binding partner of rEag1 and may modulate the functional expression of the K(+) channel in neurons.
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Affiliation(s)
- Po-Hao Hsu
- Institute of Anatomy and Cell Biology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Shi-Chuen Miaw
- Graduate Institute of Immunology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chau-Ching Chuang
- Institute of Anatomy and Cell Biology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Pei-Yu Chang
- Institute of Anatomy and Cell Biology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Ssu-Ju Fu
- Institute of Anatomy and Cell Biology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Guey-Mei Jow
- School of Medicine, Fu-Jen Catholic University, Hsin-Chuang, New Taipei City, Taiwan
| | - Mei-Miao Chiu
- Institute of Anatomy and Cell Biology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Chung-Jiuan Jeng
- Institute of Anatomy and Cell Biology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
- Brain Research Center, National Yang-Ming University, Taipei, Taiwan
- * E-mail:
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37
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Vandenberg JI, Perry MD, Perrin MJ, Mann SA, Ke Y, Hill AP. hERG K+ Channels: Structure, Function, and Clinical Significance. Physiol Rev 2012; 92:1393-478. [DOI: 10.1152/physrev.00036.2011] [Citation(s) in RCA: 463] [Impact Index Per Article: 38.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The human ether-a-go-go related gene (hERG) encodes the pore-forming subunit of the rapid component of the delayed rectifier K+ channel, Kv11.1, which are expressed in the heart, various brain regions, smooth muscle cells, endocrine cells, and a wide range of tumor cell lines. However, it is the role that Kv11.1 channels play in the heart that has been best characterized, for two main reasons. First, it is the gene product involved in chromosome 7-associated long QT syndrome (LQTS), an inherited disorder associated with a markedly increased risk of ventricular arrhythmias and sudden cardiac death. Second, blockade of Kv11.1, by a wide range of prescription medications, causes drug-induced QT prolongation with an increase in risk of sudden cardiac arrest. In the first part of this review, the properties of Kv11.1 channels, including biogenesis, trafficking, gating, and pharmacology are discussed, while the second part focuses on the pathophysiology of Kv11.1 channels.
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Affiliation(s)
- Jamie I. Vandenberg
- Mark Cowley Lidwill Research Programme in Cardiac Electrophysiology, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia; St Vincent's Clinical School, University of New South Wales, New South Wales, Australia; and University of Ottawa Heart Institute, Ottawa, Canada
| | - Matthew D. Perry
- Mark Cowley Lidwill Research Programme in Cardiac Electrophysiology, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia; St Vincent's Clinical School, University of New South Wales, New South Wales, Australia; and University of Ottawa Heart Institute, Ottawa, Canada
| | - Mark J. Perrin
- Mark Cowley Lidwill Research Programme in Cardiac Electrophysiology, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia; St Vincent's Clinical School, University of New South Wales, New South Wales, Australia; and University of Ottawa Heart Institute, Ottawa, Canada
| | - Stefan A. Mann
- Mark Cowley Lidwill Research Programme in Cardiac Electrophysiology, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia; St Vincent's Clinical School, University of New South Wales, New South Wales, Australia; and University of Ottawa Heart Institute, Ottawa, Canada
| | - Ying Ke
- Mark Cowley Lidwill Research Programme in Cardiac Electrophysiology, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia; St Vincent's Clinical School, University of New South Wales, New South Wales, Australia; and University of Ottawa Heart Institute, Ottawa, Canada
| | - Adam P. Hill
- Mark Cowley Lidwill Research Programme in Cardiac Electrophysiology, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia; St Vincent's Clinical School, University of New South Wales, New South Wales, Australia; and University of Ottawa Heart Institute, Ottawa, Canada
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38
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Krishnan Y, Li Y, Zheng R, Kanda V, McDonald TV. Mechanisms underlying the protein-kinase mediated regulation of the HERG potassium channel synthesis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1823:1273-84. [PMID: 22613764 DOI: 10.1016/j.bbamcr.2012.05.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Revised: 05/10/2012] [Accepted: 05/10/2012] [Indexed: 12/11/2022]
Abstract
The HERG (human ether-a-go-go related gene) potassium channel aids in the repolarization of the cardiomyocyte membrane at the end of each action potential. We have previously shown that sustained protein kinase A or C (PKA and PKC) activity specifically enhances channel synthesis over the course of hours to days in heterologous expression and cardiac myocytes. The kinase-mediated augmentation of the channel is post-transcriptional and occurs near or at the endoplasmic reticulum. Here we report our further investigations into the mechanisms of kinase-mediated augmentation of HERG channel protein. We show that HERG channel phosphorylation alone is not sufficient for the PKA-dependent increase to occur. In vitro translation studies indicate that an additional factor is required for the process. Pharmacologic inhibitors suggest that the channel augmentation is not due to kinase-mediated alteration in proteasome or lysosome activity. PKA activation had no effect on stability of HERG mRNA and polyribosomal profiling showed that kinase activity did not elevate translation from low to high rates. Transcriptional inhibition results suggest that the additional cellular factor is a PKA-regulated protein. Together, these findings suggest that PKA-mediated augmentation of HERG abundance is more complex than previously appreciated involving enhancement of already active translation rates, phosphorylation of the channel protein and at least one other cyclic-AMP/PKA-responsive protein. Further exploration of molecular components of this regulatory pathway will be necessary to determine exact mechanism and the biomedical impact of this process in vivo.
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Affiliation(s)
- Yamini Krishnan
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
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39
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Barros F, Domínguez P, de la Peña P. Cytoplasmic domains and voltage-dependent potassium channel gating. Front Pharmacol 2012; 3:49. [PMID: 22470342 PMCID: PMC3311039 DOI: 10.3389/fphar.2012.00049] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Accepted: 03/05/2012] [Indexed: 12/20/2022] Open
Abstract
The basic architecture of the voltage-dependent K+ channels (Kv channels) corresponds to a transmembrane protein core in which the permeation pore, the voltage-sensing components and the gating machinery (cytoplasmic facing gate and sensor–gate coupler) reside. Usually, large protein tails are attached to this core, hanging toward the inside of the cell. These cytoplasmic regions are essential for normal channel function and, due to their accessibility to the cytoplasmic environment, constitute obvious targets for cell-physiological control of channel behavior. Here we review the present knowledge about the molecular organization of these intracellular channel regions and their role in both setting and controlling Kv voltage-dependent gating properties. This includes the influence that they exert on Kv rapid/N-type inactivation and on activation/deactivation gating of Shaker-like and eag-type Kv channels. Some illustrative examples about the relevance of these cytoplasmic domains determining the possibilities for modulation of Kv channel gating by cellular components are also considered.
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Affiliation(s)
- Francisco Barros
- Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo Oviedo, Asturias, Spain
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40
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Rankinen T, Sung YJ, Sarzynski MA, Rice TK, Rao DC, Bouchard C. Heritability of submaximal exercise heart rate response to exercise training is accounted for by nine SNPs. J Appl Physiol (1985) 2011; 112:892-7. [PMID: 22174390 DOI: 10.1152/japplphysiol.01287.2011] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Endurance training-induced changes in hemodynamic traits are heritable. However, few genes associated with heart rate training responses have been identified. The purpose of our study was to perform a genome-wide association study to uncover DNA sequence variants associated with submaximal exercise heart rate training responses in the HERITAGE Family Study. Heart rate was measured during steady-state exercise at 50 W (HR50) on 2 separate days before and after a 20-wk endurance training program in 483 white subjects from 99 families. Illumina HumanCNV370-Quad v3.0 BeadChips were genotyped using the Illumina BeadStation 500GX platform. After quality control procedures, 320,000 single-nucleotide polymorphisms (SNPs) were available for the genome-wide association study analyses, which were performed using the MERLIN software package (single-SNP analyses and conditional heritability tests) and standard regression models (multivariate analyses). The strongest associations for HR50 training response adjusted for age, sex, body mass index, and baseline HR50 were detected with SNPs at the YWHAQ locus on chromosome 2p25 (P = 8.1 × 10(-7)), the RBPMS locus on chromosome 8p12 (P = 3.8 × 10(-6)), and the CREB1 locus on chromosome 2q34 (P = 1.6 × 10(-5)). In addition, 37 other SNPs showed P values <9.9 × 10(-5). After removal of redundant SNPs, the 10 most significant SNPs explained 35.9% of the ΔHR50 variance in a multivariate regression model. Conditional heritability tests showed that nine of these SNPs (all intragenic) accounted for 100% of the ΔHR50 heritability. Our results indicate that SNPs in nine genes related to cardiomyocyte and neuronal functions, as well as cardiac memory formation, fully account for the heritability of the submaximal heart rate training response.
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Affiliation(s)
- Tuomo Rankinen
- Human Genomics Laboratory, Pennington Biomedical Research Center, 6400 Perkins Rd., Baton Rouge, LA 70808-4124, USA.
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41
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Sroubek J, Krishnan Y, Chinai J, Buhl S, Scharff MD, McDonald TV. The use of Bcl-2 over-expression to stabilize hybridomas specific to the HERG potassium channel. J Immunol Methods 2011; 375:215-22. [PMID: 22107967 DOI: 10.1016/j.jim.2011.10.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Accepted: 10/26/2011] [Indexed: 01/22/2023]
Abstract
We encountered a high degree of clonal hybridoma loss in the course of generating antibodies specific for the hERG potassium channel. A protein that is crucial for controlling heart rhythm, is abundant in parts of the brain and is abnormally expressed in some tumors. Intracellular domains of the protein were used for immunogens and generated adequate antibody responses in mice. Subsequent hybridomas created using Ag8 myeloma fusion partner yielded clones that secreted specific antibody but none could be successfully maintained in culture. A variety of mechanisms, including polyploidy inherent to hybridoma development or production of cytotoxic antibodies, may be responsible for eventual loss of cell viability by mechanisms that may include apoptosis. When spleen cells were fused to the NSO myeloma cell line that stably over-expresses the anti-apoptotic protein Bcl-2, hybridoma clones were generated that remained viable in culture with high level of hERG-specific antibody production. When the parental NSO cell line not over-expressing Bcl-2 was used, no stable hybridomas were produced. Antibodies secreted by NSO-Bcl-2 hybridomas were specific for hERG and performed well in immunoblot, immunoprecipitation and immunofluorescence assays. This work demonstrates a feasible option when faced with antigens that seem to be associated with clonal instability in the process of generating monoclonal antibodies.
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Affiliation(s)
- Jakub Sroubek
- Department of Molecular Pharmacology, Wilf Family Cardiovascular Research Institute, Albert Einstein College of Medicine, Bronx, NY 10461, United States
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42
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Glassmeier G, Hempel K, Wulfsen I, Bauer CK, Schumacher U, Schwarz JR. Inhibition of HERG1 K+ channel protein expression decreases cell proliferation of human small cell lung cancer cells. Pflugers Arch 2011; 463:365-76. [PMID: 22075718 PMCID: PMC3261411 DOI: 10.1007/s00424-011-1045-z] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Revised: 10/12/2011] [Accepted: 10/14/2011] [Indexed: 01/30/2023]
Abstract
HERG (human ether-à-go-go-related gene) K+ currents fulfill important ionic functions in cardiac and other excitable cells. In addition, HERG channels influence cell growth and migration in various types of tumor cells. The mechanisms underlying these functions are still not resolved. Here, we investigated the role of HERG channels for cell growth in a cell line (SW2) derived from small cell lung cancer (SCLC), a malignant variant of lung cancer. The two HERG1 isoforms (HERG1a, HERG1b) as well as HERG2 and HERG3 are expressed in SW2 cells. Inhibition of HERG currents by acute or sustained application of E-4031, a specific ERG channel blocker, depolarized SW2 cells by 10–15 mV. This result indicated that HERG K+ conductance contributes considerably to the maintenance of the resting potential of about −45 mV. Blockage of HERG channels by E-4031 for up to 72 h did not affect cell proliferation. In contrast, siRNA-induced inhibition of HERG1 protein expression decreased cell proliferation by about 50%. Reduction of HERG1 protein expression was confirmed by Western blots. HERG current was almost absent in SW2 cells transfected with siRNA against HERG1. Qualitatively similar results were obtained in three other SCLC cell lines (OH1, OH3, H82), suggesting that the HERG1 channel protein is involved in SCLC cell growth, whereas the ion-conducting function of HERG1 seems not to be important for cell growth.
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Affiliation(s)
- Günter Glassmeier
- Institut für Zelluläre und Integrative Physiologie, Universitätsklinikum Hamburg-Eppendorf, Universität Hamburg, Martinistr. 52, D-20246, Hamburg, Germany
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43
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Smith AJ, Daut J, Schwappach B. Membrane proteins as 14-3-3 clients in functional regulation and intracellular transport. Physiology (Bethesda) 2011; 26:181-91. [PMID: 21670164 DOI: 10.1152/physiol.00042.2010] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
14-3-3 proteins regulate the function and subcellular sorting of membrane proteins. Often, 14-3-3 binding to client proteins requires phosphorylation of the client, but the relevant kinase is unknown in most cases. We summarize current progress in identifying kinases that target membrane proteins with 14-3-3 binding sites and discuss the molecular mechanisms of 14-3-3 action. One of the kinases involved is Akt/PKB, which has recently been shown to activate the 14-3-3-dependent switch in a number of client membrane proteins.
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Affiliation(s)
- Andrew J Smith
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
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44
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Kaeodee M, Pongsomboon S, Tassanakajon A. Expression analysis and response of Penaeus monodon 14-3-3 genes to salinity stress. Comp Biochem Physiol B Biochem Mol Biol 2011; 159:244-51. [DOI: 10.1016/j.cbpb.2011.05.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 05/12/2011] [Accepted: 05/12/2011] [Indexed: 10/18/2022]
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45
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Li M, Xiong ZG. Ion channels as targets for cancer therapy. INTERNATIONAL JOURNAL OF PHYSIOLOGY, PATHOPHYSIOLOGY AND PHARMACOLOGY 2011; 3:156-166. [PMID: 21760973 PMCID: PMC3134009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Accepted: 06/26/2011] [Indexed: 05/31/2023]
Abstract
Cancer is a leading cause of death in the world. Conventional treatments have severe side effects and low survival rate. It is important to discover new targets and therapeutic strategies to improve the clinical outcomes of cancer patients. Ion channels are specialized membrane proteins that play important roles in various physiological processes. Recent studies have shown that abnormal expression and/or activity of a number of ion channels e.g. voltage-gated K(+), Na(+), Ca(2+) channels, TRP channels, and epithelial Na(+)/degenerin family of ion channels, are involved in the growth/proliferation, migration and/or invasion of cancer cells. In this review, we summarize the present knowledge about the roles of different ion channels in the development of cancer.
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Affiliation(s)
- Minghua Li
- Department of Psychology, Washington State University, VancouverWA, USA
| | - Zhi-Gang Xiong
- Neuroscience Institute, Morehouse School of MedicineAtlanta, GA, USA
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46
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Saito H, Minamiya Y, Watanabe H, Takahashi N, Ito M, Toda H, Konno H, Mitsui M, Motoyama S, Ogawa JI. Expression of the Transient Receptor Potential Channel C3 Correlates with a Favorable Prognosis in Patients with Adenocarcinoma of the Lung. Ann Surg Oncol 2011; 18:3377-83. [DOI: 10.1245/s10434-011-1798-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Indexed: 12/21/2022]
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47
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Sroubek J, McDonald TV. Protein kinase A activity at the endoplasmic reticulum surface is responsible for augmentation of human ether-a-go-go-related gene product (HERG). J Biol Chem 2011; 286:21927-36. [PMID: 21536683 DOI: 10.1074/jbc.m110.201699] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human ether-a-go-go-related gene product (HERG) is a cardiac potassium channel commonly implicated in the pathogenesis of the long QT syndrome, type 2 (LQT2). LQT2 mutations typically have incomplete penetrance and affect individuals at various stages of their lives; this may mirror variations in intracellular signaling and HERG regulation. Previous work showed that sustained protein kinase A (PKA) activity augments HERG protein abundance by a mechanism that includes enhanced protein translation. To investigate the subcellular site of this regulation, we generated site-specific probes to the cytoplasmic surface of the endoplasmic reticulum (ER), the presumed locale of channel synthesis. Real-time FRET-based indicators demonstrated both cAMP and PKA activity at the ER. A PKA inhibitor targeted to the ER surface (termed p4PKIg) completely abolished PKA-mediated augmentation of HERG in HEK293 cells as well as rat neonatal cardiomyocytes. Immunofluorescence co-localization, targeted FRET-based PKA biosensors, phospho-specific antibodies, and in vivo phosphorylation experiments confirmed that p4PKIg is preferentially active at the ER surface rather than the plasma membrane. Rerouting this inhibitor to the outer mitochondrial membrane diminishes its ability to block cAMP-dependent HERG induction. Our results support a model where PKA-dependent regulation of HERG synthesis occurs at the ER surface. Furthermore, reagents generated for this study provide novel experimental tools to probe compartmentalized cAMP/PKA signaling within cells.
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Affiliation(s)
- Jakub Sroubek
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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48
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Hayashi K, Fujino N, Ino H, Uchiyama K, Sakata K, Konno T, Masuta E, Funada A, Sakamoto Y, Tsubokawa T, Hodatsu A, Yasuda T, Kanaya H, Kim MY, Kupershmidt S, Higashida H, Yamagishi M. A KCR1 variant implicated in susceptibility to the long QT syndrome. J Mol Cell Cardiol 2011; 50:50-7. [DOI: 10.1016/j.yjmcc.2010.10.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Revised: 10/02/2010] [Accepted: 10/05/2010] [Indexed: 11/25/2022]
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49
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da Silva MB, Costa VMA, Pereira VRA, de Albertim GJB, de Melo EBB, Bezerra DP, da Silva RP, Rodrigues CG, Carneiro CMM, Yuldasheva LN, Krasilnikov OV. Ion channels in volume regulation of clonal kidney cells. Cell Prolif 2010; 43:529-41. [PMID: 21039991 DOI: 10.1111/j.1365-2184.2010.00702.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVES Clonal kidney cells (Vero cells) are extensively utilized in the manufacture of biological preparations for disease diagnostics and therapeutics and also in preparation of vaccines. In all cells, regulation of volume is an essential function coupled to a variety of physiological processes and is a topic of interest. The objective here was to investigate involvement of ion channels in the process of volume regulation of Vero cells. METHODS Involvement of ion channels in cell volume regulation was studied using video-microscopy and flow cytometry. Pharmacologically unaltered cells of different sizes, which are presumably at different phases of the cell cycle, were used. RESULTS Ion transport inhibitors altered all phases of regulatory volume decrease (RVD) of Vero cells, rate of initial cell swelling, V(max) and volume recovery. Effects were dependent on type of inhibitor and on cell size (cell cycle phase). Participation of aquaporins in RVD was suggested. Inhibitors decelerated growth, arresting Vero cells at the G(0) /G(1) phase boundary. Electrophysiological study confirmed presence of volume-activated Cl(-) channels and K(+) channels in plasmatic membranes of the cells. CONCLUSION Vero cells of all sizes maintained the ability to recover from osmotic swelling. Activity of ion channels was one of the key factors that controlled volume regulation and proliferation of the cells.
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Affiliation(s)
- M B da Silva
- Department of Biophysics and Radiobiology, Federal University of Pernambuco, Recife, PE, Brazil
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50
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Role of ERG1 isoforms in modulation of ERG1 channel trafficking and function. Pflugers Arch 2010; 460:803-12. [DOI: 10.1007/s00424-010-0855-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Revised: 06/13/2010] [Accepted: 06/14/2010] [Indexed: 01/31/2023]
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