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Hilgers RHP, Das KC. Redox Regulation of K + Channel: Role of Thioredoxin. Antioxid Redox Signal 2024. [PMID: 39099341 DOI: 10.1089/ars.2023.0416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 08/06/2024]
Abstract
Significance: Potassium channels regulate the influx and efflux of K+ ions in various cell types that generate and propagate action potential associated with excitation, contraction, and relaxation of various cell types. Although redox active cysteines are critically important for channel activity, the redox regulation of K+ channels by thioredoxin (Trx) has not been systematically reviewed. Recent Advances: Redox regulation of K+ channel is now increasingly recognized as drug targets in the pathological condition of several cardiovascular disease processes. The role of Trx in regulation of these channels and its implication in pathological conditions have not been adequately reviewed. This review specifically focuses on the redox-regulatory role of Trx on K+ channel structure and function in physiological and pathophysiological conditions. Critical Issues: Ion channels, including K+ channel, have been implicated in the functioning of cardiomyocyte excitation-contraction coupling, vascular hyperpolarization, cellular proliferation, and neuronal stimulation in physiological and pathophysiological conditions. Although oxidation-reduction of ion channels is critically important in their function, the role of Trx, redox regulatory protein in regulation of these channels, and its implication in pathological conditions need to be studied to gain further insight into channel function. Future Directions: Future studies need to map all redox regulatory pathways in channel structure and function using novel mouse models and redox proteomic and signal transduction studies, which modulate various currents and altered excitability of relevant cells implicated in a pathological condition. We are yet at infancy of studies related to redox control of various K+ channels and structured and focused studies with novel animal models. Antioxid. Redox Signal. 00, 00-00.
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Affiliation(s)
- Rob H P Hilgers
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas, USA
| | - Kumuda C Das
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas, USA
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2
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Romito O, Lemettre A, Chantôme A, Champion O, Couty N, Ouldamer L, Hempel N, Trebak M, Goupille C, Potier‐Cartereau M. Plasma membrane SK2 channel activity regulates migration and chemosensitivity of high-grade serous ovarian cancer cells. Mol Oncol 2024; 18:1853-1865. [PMID: 38480668 PMCID: PMC11306528 DOI: 10.1002/1878-0261.13631] [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: 10/03/2023] [Revised: 01/30/2024] [Accepted: 02/29/2024] [Indexed: 08/09/2024] Open
Abstract
No data are currently available on the functional role of small conductance Ca2+-activated K+ channels (SKCa) in ovarian cancer. Here, we characterized the role of SK2 (KCa2.2) in ovarian cancer cell migration and chemosensitivity. Using the selective non-cell-permeant SK2 inhibitor Lei-Dab7, we identified functional SK2 channels at the plasma membrane, regulating store-operated Ca2+ entry (SOCE) in both cell lines tested (COV504 and OVCAR3). Silencing KCNN2 with short interfering RNA (siRNA), or blocking SK2 activity with Lei-Dab7, decreased cell migration. The more robust effect of KCNN2 knockdown compared to Lei-Dab7 treatment suggested the involvement of functional intracellular SK2 channels in both cell lines. In cells treated with lysophosphatidic acid (LPA), an ovarian cancer biomarker of progression, SK2 channels are a key player of LPA pro-migratory activity but their role in SOCE is abolished. Concerning chemotherapy, SK2 inhibition increased chemoresistance to Taxol® and low KCNN2 mRNA expression was associated with the worst prognosis for progression-free survival in patients with serous ovarian cancer. The dual roles of SK2 mean that SK2 activators could be used as an adjuvant chemotherapy to potentiate treatment efficacy and SK2 inhibitors could be administrated as monotherapy to limit cancer cell dissemination.
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Affiliation(s)
- Olivier Romito
- Inserm UMR 1069, Nutrition Croissance Cancer, Faculté de MédecineUniversité de ToursToursFrance
- Réseau Molécules Marines, Métabolisme et Cancer and Réseau CasTHOR Cancéropôle Grand OuestToursFrance
| | - Aude Lemettre
- Inserm UMR 1069, Nutrition Croissance Cancer, Faculté de MédecineUniversité de ToursToursFrance
- Réseau Molécules Marines, Métabolisme et Cancer and Réseau CasTHOR Cancéropôle Grand OuestToursFrance
| | - Aurélie Chantôme
- Inserm UMR 1069, Nutrition Croissance Cancer, Faculté de MédecineUniversité de ToursToursFrance
- Réseau Molécules Marines, Métabolisme et Cancer and Réseau CasTHOR Cancéropôle Grand OuestToursFrance
| | - Ophélie Champion
- Inserm UMR 1069, Nutrition Croissance Cancer, Faculté de MédecineUniversité de ToursToursFrance
- Réseau Molécules Marines, Métabolisme et Cancer and Réseau CasTHOR Cancéropôle Grand OuestToursFrance
| | - Noémie Couty
- Inserm UMR 1069, Nutrition Croissance Cancer, Faculté de MédecineUniversité de ToursToursFrance
- Réseau Molécules Marines, Métabolisme et Cancer and Réseau CasTHOR Cancéropôle Grand OuestToursFrance
| | - Lobna Ouldamer
- Inserm UMR 1069, Nutrition Croissance Cancer, Faculté de MédecineUniversité de ToursToursFrance
- Réseau Molécules Marines, Métabolisme et Cancer and Réseau CasTHOR Cancéropôle Grand OuestToursFrance
- CHRU de Tours, Service de Gynécologie et d'ObstétriqueToursFrance
| | - Nadine Hempel
- UPMC Hillman Cancer Center, Division of Hematology & Oncology, Department of MedicineUniversity of PittsburghPAUSA
| | - Mohamed Trebak
- Department of Pharmacology and Chemical Biology, Vascular Medicine InstituteUniversity of PittsburghPAUSA
| | - Caroline Goupille
- Inserm UMR 1069, Nutrition Croissance Cancer, Faculté de MédecineUniversité de ToursToursFrance
- Réseau Molécules Marines, Métabolisme et Cancer and Réseau CasTHOR Cancéropôle Grand OuestToursFrance
- CHRU de Tours, Service de Gynécologie et d'ObstétriqueToursFrance
| | - Marie Potier‐Cartereau
- Inserm UMR 1069, Nutrition Croissance Cancer, Faculté de MédecineUniversité de ToursToursFrance
- Réseau Molécules Marines, Métabolisme et Cancer and Réseau CasTHOR Cancéropôle Grand OuestToursFrance
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Mu F, Liu C, Huo H, Zeng X, Wang F. The relationship between Sjögren's syndrome and recurrent pregnancy loss: a bioinformatics analysis. Reprod Biomed Online 2024; 49:104363. [PMID: 39299134 DOI: 10.1016/j.rbmo.2024.104363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 06/20/2024] [Accepted: 07/03/2024] [Indexed: 09/22/2024]
Abstract
RESEARCH QUESTION As Sjögren's syndrome is an autoimmune disease and an essential factor in recurrent pregnancy loss (RPL), are there gene-related relationships between the pathogenesis of Sjögren's syndrome and RPL? DESIGN The gene datasets for Sjögren's syndrome and RPL were obtained from the Gene Expression Omnibus database, and the co-expression modules and shared differentially expressed genes were identified through weighted gene co-expression network analysis (WGCNA) and limma analysis based on sample size. Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes analyses were applied to reveal the hidden biological pathways. Additionally, shared hub gene identification, gene set enrichment analysis, association of the hub gene with ferroptosis and immunity, drug sensitivity analysis, single-cell RNA sequencing analysis, and construction of the competing endogenous RNA (ceRNA) network were conducted. RESULTS By intersecting the genes from WGCNA and limma analysis, one shared hub gene (KCNN3) was derived, exhibiting up-regulation in Sjögren's syndrome and RPL. There was a positive relationship between KCNN3 and the immune-related gene TLR2. The ceRNA network revealed that XIST was the most shared long non-coding RNA, which may bind competitively with eight microRNA to regulate the expression of KCNN3. Forty-eight drugs were found to be strongly associated with KCNN3 expression, including estramustine and cyclosporine. Moreover, KCNN3 exhibited high expression in RPL endothelial cells of villous tissue. CONCLUSIONS This is one of the first studies to reveal that Sjögren's syndrome shares common biological pathways with RPL. KCNN3 was identified as the hub gene associated with Sjögren's syndrome and RPL, and may be a new target for mechanistic studies on Sjögren's syndrome and RPL.
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Affiliation(s)
- Fangxiang Mu
- Department of Reproductive Medicine, Lanzhou University Second Hospital, Lanzhou, China
| | - Cai Liu
- Department of Reproductive Medicine, Lanzhou University Second Hospital, Lanzhou, China
| | - Huyan Huo
- Department of Reproductive Medicine, Lanzhou University Second Hospital, Lanzhou, China
| | - Xianghui Zeng
- Department of Reproductive Medicine, Lanzhou University Second Hospital, Lanzhou, China
| | - Fang Wang
- Department of Reproductive Medicine, Lanzhou University Second Hospital, Lanzhou, China.
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Peixoto-Neves D, Jaggar JH. Physiological functions and pathological involvement of ion channel trafficking in the vasculature. J Physiol 2024; 602:3275-3296. [PMID: 37818949 PMCID: PMC11006830 DOI: 10.1113/jp285007] [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: 08/09/2023] [Accepted: 09/28/2023] [Indexed: 10/13/2023] Open
Abstract
A variety of ion channels regulate membrane potential and calcium influx in arterial smooth muscle and endothelial cells to modify vascular functions, including contractility. The current (I) generated by a population of ion channels is equally dependent upon their number (N), open probability (Po) and single channel current (i), such that I = N.PO.i. A conventional view had been that ion channels traffic to the plasma membrane in a passive manner, resulting in a static surface population. It was also considered that channels assemble with auxiliary subunits prior to anterograde trafficking of the multimeric complex to the plasma membrane. Recent studies have demonstrated that physiological stimuli can regulate the surface abundance (N) of several different ion channels in arterial smooth muscle and endothelial cells to control arterial contractility. Physiological stimuli can also regulate the number of auxiliary subunits present in the plasma membrane to modify the biophysical properties, regulatory mechanisms and physiological functions of some ion channels. Furthermore, ion channel trafficking becomes dysfunctional in the vasculature during hypertension, which negatively impacts the regulation of contractility. The temporal kinetics of ion channel and auxiliary subunit trafficking can also vary depending on the signalling mechanisms and proteins involved. This review will summarize recent work that has uncovered the mechanisms, functions and pathological modifications of ion channel trafficking in arterial smooth muscle and endothelial cells.
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Affiliation(s)
| | - Jonathan H. Jaggar
- Department of Physiology, University of Tennessee Health Science Center, Memphis TN 38139
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Peixoto-Neves D, Yadav S, MacKay CE, Mbiakop UC, Mata-Daboin A, Leo MD, Jaggar JH. Vasodilators mobilize SK3 channels in endothelial cells to produce arterial relaxation. Proc Natl Acad Sci U S A 2023; 120:e2303238120. [PMID: 37494394 PMCID: PMC10401010 DOI: 10.1073/pnas.2303238120] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 06/20/2023] [Indexed: 07/28/2023] Open
Abstract
Endothelial cells (ECs) line the lumen of all blood vessels and regulate functions, including contractility. Physiological stimuli, such as acetylcholine (ACh) and intravascular flow, activate transient receptor potential vanilloid 4 (TRPV4) channels, which stimulate small (SK3)- and intermediate (IK)-conductance Ca2+-activated potassium channels in ECs to produce vasodilation. Whether physiological vasodilators also modulate the surface abundance of these ion channels in ECs to elicit functional responses is unclear. Here, we show that ACh and intravascular flow stimulate rapid anterograde trafficking of an intracellular pool of SK3 channels in ECs of resistance-size arteries, which increases surface SK3 protein more than two-fold. In contrast, ACh and flow do not alter the surface abundance of IK or TRPV4 channels. ACh triggers SK3 channel trafficking by activating TRPV4-mediated Ca2+ influx, which stimulates Rab11A, a Rab GTPase associated with recycling endosomes. Superresolution microscopy data demonstrate that SK3 trafficking specifically increases the size of surface SK3 clusters which overlap with TRPV4 clusters. We also show that Rab11A-dependent trafficking of SK3 channels is an essential contributor to vasodilator-induced SK current activation in ECs and vasorelaxation. In summary, our data demonstrate that vasodilators activate Rab11A, which rapidly delivers an intracellular pool of SK3 channels to the vicinity of surface TRPV4 channels in ECs. This trafficking mechanism increases surface SK3 cluster size, elevates SK3 current density, and produces vasodilation. These data also demonstrate that SK3 and IK channels are differentially regulated by trafficking-dependent and -independent signaling mechanisms in endothelial cells.
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Affiliation(s)
| | - Shambhu Yadav
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN38163
| | - Charles E. MacKay
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN38163
| | - Ulrich C. Mbiakop
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN38163
| | - Alejandro Mata-Daboin
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN38163
| | - M. Dennis Leo
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN38163
| | - Jonathan H. Jaggar
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN38163
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Pang ZD, Wang Y, Song Z, She G, Ma XZ, Sun X, Wu W, Lai BC, Zhang J, Zhang Y, Du XJ, Shyy JYJ, Deng XL. AMPK upregulates K Ca2.3 channels and ameliorates endothelial dysfunction in diet-induced obese mice. Biochem Pharmacol 2020; 183:114337. [PMID: 33186592 DOI: 10.1016/j.bcp.2020.114337] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 10/21/2020] [Accepted: 11/06/2020] [Indexed: 01/01/2023]
Abstract
The opening of endothelial small-conductance calcium-activated potassium channels (KCa2.3) is essential for endothelium-dependent hyperpolarization (EDH), which predominantly occurs in small resistance arteries. Adenosine monophosphate-activated protein kinase (AMPK), an important metabolic regulator, has been implicated in regulating endothelial nitric oxide synthase activity. However, it was unclear whether AMPK regulated endothelial KCa2.3-mediated EDH-type vasodilation. Using bioinformatics analysis and myograph system, we investigated the regulation by AMPK of KCa2.3 in human umbilical vein endothelial cells (HUVECs) or mouse second-order mesenteric resistance arteries. In HUVECs, AMPK activation either by activators (AICAR, A769662 and MK-8722) or expression of the constitutively active form of AMPK significantly upregulated KCa2.3 expression. Such effects were abolished by AMPK inhibitor (compound C) or AMPK α1-/α2-siRNA, extracellular-signal-regulated-kinase 5 (ERK5) inhibitor (ERK5-IN-1), and specific siRNA to myocyte-enhancer factor 2 (MEF2) or krüppel-like factor 2/4 (KLF2/4). KCa2.3 expression was significantly reduced in mesenteric resistance arteries in AMPKα2 knockout mice when compared with littermate control mice. Furthermore, in high-fat diet fed mice, 2-week treatment with AICAR restored endothelial KCa2.3 expression in mesenteric resistance arteries with improved endothelial dysfunction. Our results demonstrate that activation of AMPK upregulates KCa2.3 channel expression through the ERK5-MEF2-KLF2/4 signaling pathway in vascular endothelium, which contributes to benefits through KCa2.3-mediated EDH-type vasodilation in mesenteric resistance arteries.
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Affiliation(s)
- Zheng-Da Pang
- Department of Physiology and Pathophysiology, Cardiovascular Research Centre, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710061, Shaanxi, China
| | - Yan Wang
- Department of Physiology and Pathophysiology, Cardiovascular Research Centre, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710061, Shaanxi, China
| | - Zheng Song
- Department of Physiology and Pathophysiology, Cardiovascular Research Centre, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710061, Shaanxi, China
| | - Gang She
- Department of Physiology and Pathophysiology, Cardiovascular Research Centre, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710061, Shaanxi, China
| | - Xiao-Zhen Ma
- Department of Physiology and Pathophysiology, Cardiovascular Research Centre, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710061, Shaanxi, China
| | - Xia Sun
- Department of Physiology and Pathophysiology, Cardiovascular Research Centre, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710061, Shaanxi, China
| | - Wei Wu
- Department of Physiology and Pathophysiology, Cardiovascular Research Centre, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710061, Shaanxi, China
| | - Bao-Chang Lai
- Department of Physiology and Pathophysiology, Cardiovascular Research Centre, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710061, Shaanxi, China
| | - Jiao Zhang
- Division of Cardiology, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla CA 92093-0613, CA, United States
| | - Yi Zhang
- Department of Physiology and Pathophysiology, Cardiovascular Research Centre, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710061, Shaanxi, China
| | - Xiao-Jun Du
- Department of Physiology and Pathophysiology, Cardiovascular Research Centre, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710061, Shaanxi, China
| | - John Y J Shyy
- Division of Cardiology, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla CA 92093-0613, CA, United States.
| | - Xiu-Ling Deng
- Department of Physiology and Pathophysiology, Cardiovascular Research Centre, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710061, Shaanxi, China; Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an 710061, Shaanxi, China.
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Li Y, Hu H, O'Neil RG. Caveolae facilitate TRPV4-mediated Ca 2+ signaling and the hierarchical activation of Ca 2+-activated K + channels in K +-secreting renal collecting duct cells. Am J Physiol Renal Physiol 2018; 315:F1626-F1636. [PMID: 30207167 DOI: 10.1152/ajprenal.00076.2018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Transient receptor potential cation channel subfamily V member 4 (TRPV4)-mediated Ca2+ signaling induces early activation of small/intermediate Ca2+-activated K+ channels, SK3 (KCNN3) and IK1 (KCNN4), which leads to membrane hyperpolarization and enhanced Ca2+ influx, which is critical for subsequent activation of the large conductance Ca2+-activated K+ channel BK (KCNMA1) and K+ secretion in kidney cortical collecting duct (CCD) cells. The focus of the present study was to determine if such coordinated hierarchical/sequential activation of these channels in CCD was orchestrated within caveolae, a known microcompartment underlying selective Ca2+-signaling events in other cells. In K+-secreting mouse principal cell (PC) line, mCCDcl1 cells, knockdown of caveolae caveolin-1 (CAV-1) depressed TRPV4-mediated Ca2+ signaling and activation of SK3, intermediate conductance channel (IK1), and BK. Immunofluorescence colocalization analysis and coimmunoprecipitation assays demonstrated direct coupling of TRPV4 with each of the KCa channels in both mCCDcl1 and whole mouse kidney homogenates. Likewise, extending this analysis to CAV-1 demonstrates colocalization and direct coupling of CAV-1 with TRPV4, SK3, IK1, and BK, providing strong support for coupling of the channels in caveolae microdomains. Furthermore, differential expression of CAV-1 along the CCD was apparent where CAV-1 was strongly expressed within and along the cell borders of kidney PCs and intercalated cells (ICs), although significantly less in ICs. It is concluded that caveolae provide a key microdomain in PCs and ICs for coupling of TRPV4 with SK3, IK1, and BK that directly contributes to TRPV4-mediated Ca2+ signaling in these domains leading to rapid and sequential coupling of TRPV4-SK3/IK1-BK that may play a central role in mediating Ca2+-dependent regulation of BK and K+ secretion.
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Affiliation(s)
- Yue Li
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston , Houston, Texas
| | - Hongxiang Hu
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston , Houston, Texas
| | - Roger G O'Neil
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston , Houston, Texas
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Plasma membrane insertion of KCa2.3 (SK3) is dependent upon the SNARE proteins, syntaxin-4 and SNAP23. PLoS One 2018; 13:e0196717. [PMID: 29768434 PMCID: PMC5955555 DOI: 10.1371/journal.pone.0196717] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 04/18/2018] [Indexed: 02/03/2023] Open
Abstract
We previously demonstrated endocytosis of KCa2.3 is caveolin-1-, dynamin II- and Rab5-dependent. KCa2.3 then enters Rab35/EPI64C- and RME-1-containing recycling endosomes and is returned to the plasma membrane (PM). Herein, we report on the mechanism by which KCa2.3 is inserted into the PM during recycling and following exit from the Golgi. We demonstrate KCa2.3 colocalizes with SNAP-23 and Syntaxin-4 in the PM of HEK and endothelial cells by confocal immunofluorescence microscopy. We further show KCa2.3 can be co-immunoprecipitated with SNAP-23 and Syntaxin-4. Overexpression of either Syntaxin-4 or SNAP-23 increased PM expression of KCa2.3, whereas shRNA-mediated knockdown of these SNARE proteins significantly decreased PM KCa2.3 expression, as assessed by cell surface biotinylation. Whole-cell patch clamp studies confirmed knockdown of SNAP-23 significantly decreased the apamin sensitive, KCa2.3 current. Using standard biotinylation/stripping methods, we demonstrate shRNA mediated knockdown of SNAP-23 inhibits recycling of KCa2.3 following endocytosis, whereas scrambled shRNA had no effect. Finally, using biotin ligase acceptor peptide (BLAP)-tagged KCa2.3, coupled with ER-resident biotin ligase (BirA), channels could be biotinylated in the ER after which we evaluated their rate of insertion into the PM following Golgi exit. We demonstrate knockdown of SNAP-23 significantly slows the rate of Golgi to PM delivery of KCa2.3. The inhibition of both recycling and PM delivery of newly synthesized KCa2.3 channels likely accounts for the decreased PM expression observed following knockdown of these SNARE proteins. In total, our results suggest insertion of KCa2.3 into the PM depends upon the SNARE proteins, Syntaxin-4 and SNAP-23.
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9
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Lee BSL, Devor DC, Hamilton KL. Modulation of Retrograde Trafficking of KCa3.1 in a Polarized Epithelium. Front Physiol 2017; 8:489. [PMID: 28769813 PMCID: PMC5513911 DOI: 10.3389/fphys.2017.00489] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 06/26/2017] [Indexed: 12/14/2022] Open
Abstract
In epithelia, the intermediate conductance, Ca2+-activated K+ channel (KCa3.1) is targeted to the basolateral membrane (BLM) where this channel plays numerous roles in absorption and secretion. A growing body of research suggests that the membrane resident population of KCa3.1 may be critical in clinical manifestation of diseases. In this study, we investigated the key molecular components that regulate the degradation of KCa3.1 using a Fisher rat thyroid cell line stably expressing KCa3.1. Using immunoblot, Ussing chamber, and pharmacological approaches, we demonstrated that KCa3.1 is targeted exclusively to the BLM, provided a complete time course of degradation of KCa3.1 and degradation time courses of the channel in the presence of pharmacological inhibitors of ubiquitylation and deubiquitylation to advance our understanding of the retrograde trafficking of KCa3.1. We provide a complete degradation profile of KCa3.1 and that the degradation is via an ubiquitin-dependent pathway. Inhibition of E1 ubiquitin activating enzyme by UBEI-41 crippled the ability of the cells to internalize the channel, shown by the increased BLM surface expression resulting in an increased function of the channel as measured by a DCEBIO sensitive K+ current. Additionally, the involvement of deubiquitylases and degradation by the lysosome were also confirmed by treating the cells with PR-619 or leupeptin/pepstatin, respectively; which significantly decreased the degradation rate of membrane KCa3.1. Additionally, we provided the first evidence that KCa3.1 channels were not deubiquitylated at the BLM. These data further define the retrograde trafficking of KCa3.1, and may provide an avenue for therapeutic approach for treatment of disease.
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Affiliation(s)
- Bob Shih-Liang Lee
- Department of Physiology, School of Biomedical Sciences, University of OtagoDunedin, New Zealand
| | - Daniel C Devor
- Department of Cell Biology, University of Pittsburgh School of MedicinePittsburgh, PA, United States
| | - Kirk L Hamilton
- Department of Physiology, School of Biomedical Sciences, University of OtagoDunedin, New Zealand
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10
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Yap FC, Weber DS, Taylor MS, Townsley MI, Comer BS, Maylie J, Adelman JP, Lin MT. Endothelial SK3 channel-associated Ca2+ microdomains modulate blood pressure. Am J Physiol Heart Circ Physiol 2016; 310:H1151-63. [PMID: 26945080 DOI: 10.1152/ajpheart.00787.2015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 02/22/2016] [Indexed: 11/22/2022]
Abstract
Activation of vascular endothelial small- (KCa2.3, SK3) or intermediate- (KCa3.1, IK1) conductance Ca(2+)-activated potassium channels induces vasorelaxation via an endothelium-derived hyperpolarization (EDH) pathway. Although the activation of SK3 and IK1 channels converges on EDH, their subcellular effects on signal transduction are different and not completely clear. In this study, a novel endothelium-specific SK3 knockout (SK3(-/-)) mouse model was utilized to specifically examine the contribution of SK3 channels to mesenteric artery vasorelaxation, endothelial Ca(2+) dynamics, and blood pressure. The absence of SK3 expression was confirmed using real-time quantitative PCR and Western blot analysis. Functional studies showed impaired EDH-mediated vasorelaxation in SK3(-/-) small mesenteric arteries. Immunostaining results from SK3(-/-) vessels confirmed the absence of SK3 and further showed altered distribution of transient receptor potential channels, type 4 (TRPV4). Electrophysiological recordings showed a lack of SK3 channel activity, while TRPV4-IK1 channel coupling remained intact in SK3(-/-) endothelial cells. Moreover, Ca(2+) imaging studies in SK3(-/-) endothelium showed increased Ca(2+) transients with reduced amplitude and duration under basal conditions. Importantly, SK3(-/-) endothelium lacked a distinct type of Ca(2+) dynamic that is sensitive to TRPV4 activation. Blood pressure measurements showed that the SK3(-/-) mice were hypertensive, and the blood pressure increase was further enhanced during the 12-h dark cycle when animals are most active. Taken together, our results reveal a previously unappreciated SK3 signaling microdomain that modulates endothelial Ca(2+) dynamics, vascular tone, and blood pressure.
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Affiliation(s)
- Fui C Yap
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, Alabama
| | - David S Weber
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, Alabama
| | - Mark S Taylor
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, Alabama
| | - Mary I Townsley
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, Alabama
| | - Brian S Comer
- Department of Cellular and Integrative Physiology, Indiana University, Indianapolis, Indiana
| | - James Maylie
- Department of Obstetrics and Gynecology, Oregon Health & Science University, Portland, Oregon; and
| | - John P Adelman
- Vollum Institute, Oregon Health & Science University, Portland, Oregon
| | - Mike T Lin
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, Alabama;
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Calcium-Activated Potassium Channels: Potential Target for Cardiovascular Diseases. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2015; 104:233-261. [PMID: 27038376 DOI: 10.1016/bs.apcsb.2015.11.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Ca(2+)-activated K(+) channels (KCa) are classified into three subtypes: big conductance (BKCa), intermediate conductance (IKCa), and small conductance (SKCa) KCa channels. The three types of KCa channels have distinct physiological or pathological functions in cardiovascular system. BKCa channels are mainly expressed in vascular smooth muscle cells (VSMCs) and inner mitochondrial membrane of cardiomyocytes, activation of BKCa channels in these locations results in vasodilation and cardioprotection against cardiac ischemia. IKCa channels are expressed in VSMCs, endothelial cells, and cardiac fibroblasts and involved in vascular smooth muscle proliferation, migration, vessel dilation, and cardiac fibrosis. SKCa channels are widely expressed in nervous and cardiovascular system, and activation of SKCa channels mainly contributes membrane hyperpolarization. In this chapter, we summarize the physiological and pathological roles of the three types of KCa channels in cardiovascular system and put forward the possibility of KCa channels as potential target for cardiovascular diseases.
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Goedicke-Fritz S, Kaistha A, Kacik M, Markert S, Hofmeister A, Busch C, Bänfer S, Jacob R, Grgic I, Hoyer J. Evidence for functional and dynamic microcompartmentation of Cav-1/TRPV4/KCa in caveolae of endothelial cells. Eur J Cell Biol 2015; 94:391-400. [DOI: 10.1016/j.ejcb.2015.06.002] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Lin MT, Jian MY, Taylor MS, Cioffi DL, Yap FC, Liedtke W, Townsley MI. Functional coupling of TRPV4, IK, and SK channels contributes to Ca(2+)-dependent endothelial injury in rodent lung. Pulm Circ 2015; 5:279-90. [PMID: 26064452 DOI: 10.1086/680166] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 09/15/2014] [Indexed: 02/05/2023] Open
Abstract
Our previous work has shown that the increased lung endothelial permeability response to 14,15-epoxyeicosatrienoic acid (14,15-EET) in rat lung requires Ca(2+) entry via vanilloid type-4 transient receptor potential (TRPV4) channels. Recent studies suggest that activation of TRPV4 channels in systemic vascular endothelium prolongs agonist-induced hyperpolarization and amplifies Ca(2+) entry by activating Ca(2+)-activated K(+) (KCa) channels, resulting in vessel relaxation. Activation of endothelial KCa channels thus has potential to increase the electrochemical driving force for Ca(2+) influx via TRPV4 channels and to amplify permeability responses to TRPV4 activation in lung. To examine this hypothesis, we used Western blot analysis, electrophysiological recordings, and isolated-lung permeability measurements to document expression of TRPV4 and KCa channels and the potential for functional coupling. The results show that rat pulmonary microvascular endothelial cells express TRPV4 and 3 KCa channels of different conductances: large (BK), intermediate (IK), and small (SK3). However, TRPV4 channel activity modulates the IK and SK3, but not the BK, channel current density. Furthermore, the TRPV4-mediated permeability response to 14,15-EET in mouse lung is significantly attenuated by pharmacologic blockade of IK and SK3, but not BK, channels. Collectively, this functional coupling suggests that endothelial TRPV4 channels in rodent lung likely form signaling microdomains with IK and SK3 channels and that the integrated response dictates the extent of lung endothelial injury caused by 14,15-EET.
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Affiliation(s)
- Mike T Lin
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, Alabama, USA ; These authors contributed equally to this work
| | - Ming-Yuan Jian
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, Alabama, USA ; Center for Lung Biology, University of South Alabama, Mobile, Alabama, USA ; Present address: Department of Anesthesiology, University of Alabama at Birmingham, Birmingham, Alabama, USA. ; These authors contributed equally to this work
| | - Mark S Taylor
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, Alabama, USA
| | - Donna L Cioffi
- Center for Lung Biology, University of South Alabama, Mobile, Alabama, USA ; Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, USA
| | - Fui C Yap
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, Alabama, USA
| | - Wolfgang Liedtke
- Departments of Medicine, Neurology and Neurobiology, Duke University, Durham, North Carolina, USA
| | - Mary I Townsley
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, Alabama, USA ; Center for Lung Biology, University of South Alabama, Mobile, Alabama, USA ; Department of Medicine, University of South Alabama, Mobile, Alabama, USA
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Tao X, Lin MT, Thorington GU, Wilson SM, Longo LD, Hessinger DA. Long-term hypoxia increases calcium affinity of BK channels in ovine fetal and adult cerebral artery smooth muscle. Am J Physiol Heart Circ Physiol 2015; 308:H707-22. [PMID: 25599571 DOI: 10.1152/ajpheart.00564.2014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 01/14/2015] [Indexed: 01/31/2023]
Abstract
Acclimatization to high-altitude, long-term hypoxia (LTH) reportedly alters cerebral artery contraction-relaxation responses associated with changes in K(+) channel activity. We hypothesized that to maintain oxygenation during LTH, basilar arteries (BA) in the ovine adult and near-term fetus would show increased large-conductance Ca(2+) activated potassium (BK) channel activity. We measured BK channel activity, expression, and cell surface distribution by use of patch-clamp electrophysiology, flow cytometry, and confocal microscopy, respectively, in myocytes from normoxic control and LTH adult and near-term fetus BA. Electrophysiological data showed that BK channels in LTH myocytes exhibited 1) lowered Ca(2+) set points, 2) left-shifted activation voltages, and 3) longer dwell times. BK channels in LTH myocytes also appeared to be more dephosphorylated. These differences collectively make LTH BK channels more sensitive to activation. Studies using flow cytometry showed that the LTH fetus exhibited increased BK β1 subunit surface expression. In addition, in both fetal groups confocal microscopy revealed increased BK channel clustering and colocalization to myocyte lipid rafts. We conclude that increased BK channel activity in LTH BA occurred in association with increased channel affinity for Ca(2+) and left-shifted voltage activation. Increased cerebrovascular BK channel activity may be a mechanism by which LTH adult and near-term fetal sheep can acclimatize to long-term high altitude hypoxia. Our findings suggest that increasing BK channel activity in cerebral myocytes may be a therapeutic target to ameliorate the adverse effects of high altitude in adults or of intrauterine hypoxia in the fetus.
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Affiliation(s)
- Xiaoxiao Tao
- Division of Pharmacology, School of Medicine, Loma Linda University, Loma Linda, California
| | - Mike T Lin
- Division of Physiology, School of Medicine, Loma Linda University, Loma Linda, California; Department of Physiology and Cell Biology, University of South Alabama, Mobile, Alabama
| | - Glyne U Thorington
- Division of Physiology, School of Medicine, Loma Linda University, Loma Linda, California
| | - Sean M Wilson
- Division of Pharmacology, School of Medicine, Loma Linda University, Loma Linda, California; Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, California; and
| | - Lawrence D Longo
- Division of Physiology, School of Medicine, Loma Linda University, Loma Linda, California; Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, California; and
| | - David A Hessinger
- Division of Pharmacology, School of Medicine, Loma Linda University, Loma Linda, California; Division of Physiology, School of Medicine, Loma Linda University, Loma Linda, California;
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Mahida S. Genetic Discoveries in Atrial Fibrillation and Implications for Clinical Practice. Arrhythm Electrophysiol Rev 2014; 3:69-75. [PMID: 26835069 DOI: 10.15420/aer.2014.3.2.69] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 07/04/2014] [Indexed: 11/04/2022] Open
Abstract
Atrial fibrillation (AF) is an arrhythmia with a genetic basis. Over the past decade, rapid advances in genotyping technology have revolutionised research regarding the genetic basis of AF. While AF genetics research was previously largely restricted to familial forms of AF, recent studies have begun to characterise the genetic architecture underlying the form of AF encountered in everyday clinical practice. These discoveries could have a significant impact on the management of AF. However, much work remains before genetic findings can be translated to clinical practice. This review summarises results of studies in AF genetics to date and discusses the potential implications of these findings in clinical practice.
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Kochukov MY, Balasubramanian A, Abramowitz J, Birnbaumer L, Marrelli SP. Activation of endothelial transient receptor potential C3 channel is required for small conductance calcium-activated potassium channel activation and sustained endothelial hyperpolarization and vasodilation of cerebral artery. J Am Heart Assoc 2014; 3:jah3649. [PMID: 25142058 PMCID: PMC4310376 DOI: 10.1161/jaha.114.000913] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background Transient receptor potential C3 (TRPC3) has been demonstrated to be involved in the regulation of vascular tone through endothelial cell (EC) hyperpolarization and endothelium‐dependent hyperpolarization–mediated vasodilation. However, the mechanism by which TRPC3 regulates these processes remains unresolved. We tested the hypothesis that endothelial receptor stimulation triggers rapid TRPC3 trafficking to the plasma membrane, where it provides the source of Ca2+ influx for small conductance calcium‐activated K+ (SKCa) channel activation and sustained EC hyperpolarization. Methods and Results Pressurized artery studies were performed with isolated mouse posterior cerebral artery. Treatment with a selective TRPC3 blocker (Pyr3) produced significant attenuation of endothelium‐dependent hyperpolarization–mediated vasodilation and endothelial Ca2+ response (EC‐specific Ca2+ biosensor) to intraluminal ATP. Pyr3 treatment also resulted in a reduced ATP‐stimulated global Ca2+ and Ca2+ influx in primary cultures of cerebral endothelial cells. Patch‐clamp studies with freshly isolated cerebral ECs demonstrated 2 components of EC hyperpolarization and K+ current activation in response to ATP. The early phase was dependent on intermediate conductance calcium‐activated K+ channel activation, whereas the later sustained phase relied on SKCa channel activation. The SKCa channel–dependent phase was completely blocked with TRPC3 channel inhibition or in ECs of TRPC3 knockout mice and correlated with increased trafficking of TRPC3 (but not SKCa channel) to the plasma membrane. Conclusions We propose that TRPC3 dynamically regulates SKCa channel activation through receptor‐dependent trafficking to the plasma membrane, where it provides the source of Ca2+ influx for sustained SKCa channel activation, EC hyperpolarization, and endothelium‐dependent hyperpolarization–mediated vasodilation.
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Affiliation(s)
- Mikhail Y Kochukov
- Department of Anesthesiology, Baylor College of Medicine, Houston, TX (M.Y.K., A.B., S.P.M.)
| | - Adithya Balasubramanian
- Department of Anesthesiology, Baylor College of Medicine, Houston, TX (M.Y.K., A.B., S.P.M.)
| | - Joel Abramowitz
- Division of Intramural Research, National Institute of Environmental Health Sciences Research, Triangle Park, NC (J.A., L.B.)
| | - Lutz Birnbaumer
- Division of Intramural Research, National Institute of Environmental Health Sciences Research, Triangle Park, NC (J.A., L.B.)
| | - Sean P Marrelli
- Department of Anesthesiology, Baylor College of Medicine, Houston, TX (M.Y.K., A.B., S.P.M.) Department of Physiology and Biophysics and Graduate Program in Physiology, Cardiovascular Sciences Track, Baylor College of Medicine, Houston, TX (S.P.M.)
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Ovariectomy-induced reductions in endothelial SK3 channel activity and endothelium-dependent vasorelaxation in murine mesenteric arteries. PLoS One 2014; 9:e104686. [PMID: 25105912 PMCID: PMC4126749 DOI: 10.1371/journal.pone.0104686] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 07/14/2014] [Indexed: 12/15/2022] Open
Abstract
Mesenteric artery endothelium expresses both small (SK3)- and intermediate (IK1)-conductance Ca(2+)-activated K(+) (KCa) channels whose activity modulates vascular tone via endothelium-dependent hyperpolarization (EDH). Two other major endothelium-dependent vasodilation pathways utilize nitric oxide (NO) and prostacyclin (PGI2). To examine how ovariectomy (ovx) affects the basal activity and acetylcholine (ACh)-induced activity of each of these three pathways to vasorelaxation, we used wire myograph and electrophysiological recordings. The results from functional studies using isolated murine mesenteric arteries show that ovx reduces ACh-induced endothelium-dependent vasodilation due to decreased EDH and NO contributions, although the contribution of PGI2 is upregulated. Both endothelial SK3 and IK1 channels are functionally coupled to TRPV4 (transient receptor potential, vanilloid type 4) channels: the activation of TRPV4 channels activates SK3 and IK1 channels, leading to EDH-mediated vascular relaxation. The decreased EDH-mediated vasorelaxation in ovx vessels is due to reduced SK3 channel contribution to the pathway. Further, whole-cell recordings using dispersed endothelial cells also show reduced SK3 current density in ovx endothelial cells. Consequently, activation of TRPV4 channels induces smaller changes in whole-cell current density. Thus, ovariectomy leads to a reduction in endothelial SK3 channel activity thereby reducing the SK3 contribution to EDH vasorelaxation.
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Mason L, Tribolet L, Simon A, von Gnielinski N, Nienaber L, Taylor P, Willis C, Jones MK, Sternberg PW, Gasser RB, Loukas A, Hofmann A. Probing the equatorial groove of the hookworm protein and vaccine candidate antigen, Na-ASP-2. Int J Biochem Cell Biol 2014; 50:146-55. [PMID: 24631931 DOI: 10.1016/j.biocel.2014.03.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 02/23/2014] [Accepted: 03/04/2014] [Indexed: 11/17/2022]
Abstract
Hookworm activation-associated secreted proteins can be structurally classified into at least three different groups. The hallmark feature of Group 1 activation-associated secreted proteins is a prominent equatorial groove, which is inferred to form a ligand binding site. Furthermore, a conserved tandem histidine motif is located in the centre of the groove and believed to provide or support a yet to be determined catalytic activity. Here, we report three-dimensional crystal structures of Na-ASP-2, an L3-secreted activation-associated secreted protein from the human hookworm Necator americanus, which demonstrate transition metal binding ability of the conserved tandem histidine motif. We further identified moderate phosphohydrolase activity of recombinant Na-ASP-2, which relates to the tandem histidine motif. By panning a random 12-mer peptide phage library, we identified a peptide with high similarity to the human calcium-activated potassium channel SK3, and confirm binding of the synthetic peptide to recombinant Na-ASP-2 by differential scanning fluorimetry. Potential binding modes of the peptide to Na-ASP-2 were studied by molecular dynamics simulations which clearly identify a preferred topology of the Na-ASP-2:SK3 peptide complex.
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Affiliation(s)
- Lyndel Mason
- Structural Chemistry Program, Eskitis Institute, Griffith University, Brisbane, Queensland, Australia
| | - Leon Tribolet
- Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Queensland, Australia
| | - Anne Simon
- Université Lyon 1, Villeurbanne cedex, and Laboratoire Chimie et Biologie des Membranes et des Nanoobjets, Université Bordeaux, CBMN, UMR 5248, 33600 Pessac, France
| | - Natascha von Gnielinski
- Structural Chemistry Program, Eskitis Institute, Griffith University, Brisbane, Queensland, Australia
| | - Lisa Nienaber
- Structural Chemistry Program, Eskitis Institute, Griffith University, Brisbane, Queensland, Australia
| | - Paul Taylor
- Institute for Structural Biology, School of Biological Sciences, The University of Edinburgh, Scotland, UK
| | - Charlene Willis
- Structural Chemistry Program, Eskitis Institute, Griffith University, Brisbane, Queensland, Australia; School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia
| | - Malcolm K Jones
- School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia; Queensland Institute of Medical Research, Herston, Queensland, Australia
| | - Paul W Sternberg
- Biology Division, California Institute of Technology, Pasadena, CA, USA
| | - Robin B Gasser
- Faculty of Veterinary Science, The University of Melbourne, Parkville, Victoria, Australia
| | - Alex Loukas
- Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Queensland, Australia.
| | - Andreas Hofmann
- Structural Chemistry Program, Eskitis Institute, Griffith University, Brisbane, Queensland, Australia; Faculty of Veterinary Science, The University of Melbourne, Parkville, Victoria, Australia.
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Hernandez VJ, Weng J, Ly P, Pompey S, Dong H, Mishra L, Schwarz M, Anderson RGW, Michaely P. Cavin-3 dictates the balance between ERK and Akt signaling. eLife 2013; 2:e00905. [PMID: 24069528 PMCID: PMC3780650 DOI: 10.7554/elife.00905] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2013] [Accepted: 08/14/2013] [Indexed: 12/22/2022] Open
Abstract
Cavin-3 is a tumor suppressor protein of unknown function. Using both in vivo and in vitro approaches, we show that cavin-3 dictates the balance between ERK and Akt signaling. Loss of cavin-3 increases Akt signaling at the expense of ERK, while gain of cavin-3 increases ERK signaling at the expense Akt. Cavin-3 facilitates signal transduction to ERK by anchoring caveolae to the membrane skeleton of the plasma membrane via myosin-1c. Caveolae are lipid raft specializations that contain an ERK activation module and loss of the cavin-3 linkage reduces the abundance of caveolae, thereby separating this ERK activation module from signaling receptors. Loss of cavin-3 promotes Akt signaling through suppression of EGR1 and PTEN. The in vitro consequences of the loss of cavin-3 include induction of Warburg metabolism (aerobic glycolysis), accelerated cell proliferation, and resistance to apoptosis. The in vivo consequences of cavin-3 knockout are increased lactate production and cachexia. DOI:http://dx.doi.org/10.7554/eLife.00905.001.
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Affiliation(s)
- Victor J Hernandez
- Department of Cell Biology , University of Texas Southwestern Medical Center , Dallas , United States
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Abstract
Over the past decade, compelling evidence has emerged from population-based studies to suggest that AF is a heritable disease. More recently, we have begun to elucidate the genetic substrate underlying AF. Genome-wide association studies (GWAS) have led to the identification of multiple risk loci that confer increased susceptibility to the arrhythmia. These loci harbor intriguing candidate genes including those encoding ion channels, transcription factors, and signaling molecules. Current efforts are ongoing to functionally validate the role of these genes in disease pathogenesis. In the future, novel genotyping technologies such as exome sequencing and whole-genome sequencing promise to uncover a greater proportion of the heritability underlying AF. In this article we review recent advances in AF genetics research and discuss future developments in the field.
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Affiliation(s)
- Saagar Mahida
- Cardiovascular Research Center, Massachusetts General Hospital, Charlestown, MA, USA
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