DOCSLIB.ORG

Potassium Channels in the Heart: Structure, Function and Regulation

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Potassium Channels in the Heart: Structure, Function and Regulation J Physiol 595.7 (2017) pp 2209–2228 2209 WHITE PAPER Potassium channels in the heart: structure, function and regulation Eleonora Grandi1, Michael C. Sanguinetti2, Daniel C. Bartos1,DonaldM.Bers1, Ye Chen-Izu1,3, Nipavan Chiamvimonvat3, Henry M. Colecraft4, Brian P. Delisle5, Jordi Heijman6 , Manuel F. Navedo1, Sergei Noskov7, Catherine Proenza8, Jamie I. Vandenberg9 and Vladimir Yarov-Yarovoy10 1Department of Pharmacology, University of California, Davis, Davis, CA 95616, USA 2Department of Internal Medicine, University of Utah, Nora Eccles Harrison Cardiovascular Research and Training Institute, Salt Lake City, UT 84112, USA 3Department of Internal Medicine, Division of Cardiology, University of California, Davis, CA 95616, USA 4Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA 5Department of Physiology, University of Kentucky, Lexington, KY 40536, USA 6Department of Cardiology, Cardiovascular Research Institute Maastricht, Faculty of Health, Medicine, and Life Sciences, Maastricht University, Maastricht, The Netherlands 7Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, AB, T2N 1N4, Canada 8Department of Physiology and Biophysics, University of Colorado - Anschutz Medical Campus, Denver, CO 80045, USA 9Victor Chang Cardiac Research Institute, Darlinghurst, NSW, 2010, Australia 10Department of Physiology and Membrane Biology, University of California, Davis, CA 95616, USA Abstract This paper is the outcome of the fourth UC Davis Systems Approach to Understanding Cardiac Excitation–Contraction Coupling and Arrhythmias Symposium, a biannual event that aims to bring together leading experts in subfields of cardiovascular biomedicine to focus on topics of importance to the field. The theme of the 2016 symposium was ‘K+ Channels and Regulation’. Experts in the field contributed their experimental and mathematical modelling perspectives and discussed emerging questions, controversies and challenges on the topic of cardiac K+ channels. This paper summarizes the topics of formal presentations and informal discussions from the symposium on the structural basis of voltage-gated K+ channel function, as well as the mechanisms involved in regulation of K+ channel gating, expression and membrane localization. Given the critical role for K+ channels in determining the rate of cardiac repolarization, it is hardly surprising that essentially every aspect of K+ channel function is exquisitely regulated in cardiac myocytes. This regulation is complex and highly interrelated to other aspects of myocardial function. K+ channel regulatory mechanisms alter, and are altered by, physiological challenges, The Journal of Physiology pathophysiological conditions, and pharmacological agents. An accompanying paper focuses on the integrative role of K+ channels in cardiac electrophysiology, i.e. how K+ currents shape the cardiac action potential, and how their dysfunction can lead to arrhythmias, and discusses K+ channel-based therapeutics. A fundamental understanding of K+ channel regulatory mechanisms and disease processes is fundamental to reveal new targets for human therapy. (Received 28 May 2016; accepted after revision 18 July 2016) Corresponding author E. Grandi: Department of Pharmacology, Genome and Biomedical Sciences Facility, Room 3502, University of California, Davis, Davis, CA, USA. Email: [email protected] Abbreviations AF, atrial fibrillation; AP, action potential; APD, action potential duration; CaMKII, Ca2+/calmodulin-dependent protein kinase II; COP, coatamer associated protein; cryo-EM, cryo-electron microscopy; ER, endoplasmic reticulum; HF, heart failure; hiPSC-CM, human induced pluripotent stem cell-derived cardiomyocyte; + IPC, ischaemic preconditioning; KV,voltage-gatedK ; LQTS, long QT syndrome; MD, molecular dynamics; PIP2, phosphatidylinositol-4,5-bisphosphate; REFER, rate-equilibrium free energy; RMP, resting membrane potential; SR, sarcoplasmic reticulum; SUR, sulfonylurea receptor; VSD, voltage sensor domain. C 2016 The Authors. The Journal of Physiology C 2016 The Physiological Society DOI: 10.1113/JP272864 2210 E. Grandi and others J Physiol 595.7 Voltage-gated K+ channel structure voltage-gated channels; however, we are still trying to and function work out the precise details of the structural basis of channel function. Perhaps the most prescient prediction In this session Toby Allen, Francisco Bezanilla, Jianmin made by Hodgkin and Huxley, was that ‘changes in Cui, Peter Larsson, Daniel Minor, Sergei Noskov, Jon ionic permeability depend on the movement of some Sack, Matthew Trudeau, Jamie Vandenberg and Vladimir component of the membrane which behaves as though Yarov-Yarovoy participated as speakers, discussion leaders, it had a large charge or dipole moment’ (Hodgkin & or panelists. + Huxley, 1952). Twenty years passed before the small Voltage-gated K (KV) channels are gated pores in transient current associated with the movement of this the membranes of excitable cells that open and close in charge, the gating current, was first recorded (Armstrong response to changes in transmembrane voltage to allow + & Bezanilla, 1973). Measuring gating currents remains the selective passage of K ions across the cell membrane to this day at the centre of ongoing efforts to under- (Bezanilla, 2000). The existence of KV channels was first stand how voltage sensors work (see e.g. Lacroix et al. inferred over 60 years ago through a combination of 2014). It was another decade before cloning of the first functional and theoretical studies in the squid giant axon members of the voltage-gated ion channel family led to (Hodgkin & Huxley, 1952). Many of the principles under- the identification of the S4 transmembrane domain, with lying how these channels sense change in membrane its multiple arginine residues, as the principal component voltage and then transduce that into the opening and of the voltage-sensing domain in these channels (Noda closing of the voltage-dependent gates are now well et al. 1984; Papazian et al. 1987). In the last 20 years, established, but there is still a way to go before we will the development of methods to attach chemical probes understand voltage sensing and voltage sensor to pore ranging from H+ (Starace & Bezanilla, 2001) to fluoro- coupling at the same atomic level resolution that we under- phores (Mannuzzu et al. 1996) to electron paramagnetic stand the basis of ion selectivity (Zhou et al. 2001; Medovoy resonance probes (Cuello et al. 2004) has allowed indirect et al. 2016). monitoring of the motion of the voltage-sensor domain. Our current understanding of the molecular basis + These spectroscopic methods have complemented gating of cardiac K channel function, including selective current measurements in our quest to understand the ion permeation, voltage sensing and gating, is derived extraordinary molecular gymnastics that underlie the from a combination of experimental observations and function of these channels. Recent studies utilizing these modelling. Heterologous expression of cloned channels techniques have revealed the gating mechanisms for has greatly facilitated quantitative biophysical and several cardiac KV channels, including KV11.1 (ERG1) structural studies of K+ channels. Static structures + (Es-Salah-Lamoureux et al. 2010), KV1.5 (Vaid et al. 2009), of prokaryotic K channels (e.g. KcsA, MthK, KVAP, + and IKs channels formed by co-assembly of KV7.1 with KirBac1.1, Kir3.1/KirBac1.3 chimera) and eukaryotic K KCNE1 (minK) accessory subunits (Barro-Soria et al. channels (e.g. Kir2.2, KV1.2) determined by X-ray 2014; Zaydman et al. 2014). crystallography and more recently by cryo-electron micro- In most KV channels that have been investigated, the scopy (cryo-EM) for Slo2.2 (Hite et al. 2015) have provided voltage dependence of the voltage sensor domain (VSD) crucial information for constructing homology models + movement occurs over a more negative voltage range than of cardiac K channels whose structures have yet to that required for channel activation. Channel opening only be solved. These structures have also enabled molecular occurs after all the VSDs have been activated, and involves dynamics (MD) simulations that provide insights into the a final highly cooperative state transition. In a process mechanisms of ion selectivity and permeation, channel called electromechanical coupling, S4–S5 linkers act as gating and ligand binding at an atomic level of detail. mechanical levers that couple outward movement of the Structures have not yet been determined for most of S4 segments to opening of the pore domain (Long et al. the cardiac K+ channels. However, structures of highly + 2005b; Jensen et al. 2012). Recent studies have revealed related mammalian K channels (i.e. KV1.2, Kir3.2 and that gating of KV7.1 and KV11.1 channels differs from this Slo2.2) as well as the cytoplasmic domains of Kir2.1, Kir3.1 canonical model. Quite unexpectedly, channel gating is and KV11.1 are available and provide useful templates to relatively normal when KV11.1 subunits are split at the construct homology models. S4/S5 linker into separate VSD and pore domains and Questions, controversies, challenges: heterologously expressed in oocytes (Lorinczi et al. 2015). r Split KV1orKV7.1 channels are non-functional. Thus, a What do we know about the mechanisms of voltage rigid covalent linkage between the S4 and S5 segments is sensing? not required for normal gating of all KV channels. Given In a seminal series of papers published
Load more

Recommended publications
  • TRP Channels in Digestive Tract Cancers
    International Journal of Molecular Sciences Review TRP Channels in Digestive Tract Cancers Paulina Stokłosa *, Anna Borgström, Sven Kappel and Christine Peinelt Institute of Biochemistry and Molecular Medicine, National Center of Competence in Research NCCR TransCure, University of Bern, 3012 Bern, Switzerland; [email protected] (A.B.); [email protected] (S.K.); [email protected] (C.P.) * Correspondence: [email protected]; Tel.: +0041-(0)31-631-34-26 Received: 10 February 2020; Accepted: 6 March 2020; Published: 9 March 2020 Abstract: Cancers of the digestive tract are among the most prevalent types of cancer. These types of cancers are often diagnosed at a late stage, which results in a poor prognosis. Currently, many biomedical studies focus on the role of ion channels, in particular transient receptor potential (TRP) channels, in cancer pathophysiology. TRP channels show mostly non-selective permeability to monovalent and divalent cations. TRP channels are often dysregulated in digestive tract cancers, which can result in alterations of cancer hallmark functions, such as enhanced proliferation, migration, invasion and the inability to induce apoptosis. Therefore, TRP channels could serve as potential diagnostic biomarkers. Moreover, TRP channels are mostly expressed on the cell surface and ion channel targeting drugs do not need to enter the cell, making them attractive candidate drug targets. In this review, we summarize the current knowledge about TRP channels in connection to digestive tract cancers (oral cancer, esophageal cancer, liver cancer, pancreatic cancer, gastric cancer and colorectal cancer) and give an outlook on the potential of TRP channels as cancer biomarkers or therapeutic targets.
    [Show full text]
  • ION CHANNEL DIVERSITY and CHARACTERIZATION
    ION CHANNEL DIVERSITY and CHARACTERIZATION Voltage clamp techniques K channels Na channels Ca channels Ligand-gated channels Channelopathies OUTLINE Voltage clamp techniques whole cell, single channel, gating K channels Na channels Ca channels Cardiac AP Na nerve vs cardiac Ica: L vs T type; drugs (BayK, nitrendipine) Ito: inactivation, subtypes Kv1.4, Kv4.2/3, accessory subunits Ikr,Iks, Ikur (drugs dofetilide) IK1 – rectification Cardiac channelopathies (LQTS, SQTS, Brugada syndrome) Ligand-gated channels (AChR) Pancreatic beta cell channels (KATP, ICa) Voltage clamp techniques Capacitance currents (Ic) and ionic currents (Ii) are activated by rapid changes in membrane potential using voltage clamp Variable Vtest can be applied with voltage clamp 2.0 sec 40 duration 20 (10 sec between each pulse) 0 -20 mV test -40 V -60 -80 Simplified schematic of voltage clamp circuit Original patch clamp recordings (1981) Pflugers Arch 391: 85-100 Four modes of patch clamp technique High-throughput, automated patch clamp instruments EVOLUTION and Ion channel diversity Diversity of ion channels Example: nematode C. elegans 73 K channels (20 6 TM, 3 IRK, 50 TWIK) 89 ligand-gated channels (42 ACh, 37 inhibitory GABAA or glutamate, 10 excitatory glutamate) 5 voltage-gated Ca channels 6 chloride channels 24 gap junction channels (connexins) 22 mechanosensitive channels 6 cyclic-nucleotide gated channels 11 TRP-related channels Total: 236 channel subunit genes Origin of ion channel diversity 1) gene duplication & divergence 2) alternative mRNA splicing 3)
    [Show full text]
  • The Mineralocorticoid Receptor Leads to Increased Expression of EGFR
    www.nature.com/scientificreports OPEN The mineralocorticoid receptor leads to increased expression of EGFR and T‑type calcium channels that support HL‑1 cell hypertrophy Katharina Stroedecke1,2, Sandra Meinel1,2, Fritz Markwardt1, Udo Kloeckner1, Nicole Straetz1, Katja Quarch1, Barbara Schreier1, Michael Kopf1, Michael Gekle1 & Claudia Grossmann1* The EGF receptor (EGFR) has been extensively studied in tumor biology and recently a role in cardiovascular pathophysiology was suggested. The mineralocorticoid receptor (MR) is an important efector of the renin–angiotensin–aldosterone‑system and elicits pathophysiological efects in the cardiovascular system; however, the underlying molecular mechanisms are unclear. Our aim was to investigate the importance of EGFR for MR‑mediated cardiovascular pathophysiology because MR is known to induce EGFR expression. We identifed a SNP within the EGFR promoter that modulates MR‑induced EGFR expression. In RNA‑sequencing and qPCR experiments in heart tissue of EGFR KO and WT mice, changes in EGFR abundance led to diferential expression of cardiac ion channels, especially of the T‑type calcium channel CACNA1H. Accordingly, CACNA1H expression was increased in WT mice after in vivo MR activation by aldosterone but not in respective EGFR KO mice. Aldosterone‑ and EGF‑responsiveness of CACNA1H expression was confrmed in HL‑1 cells by Western blot and by measuring peak current density of T‑type calcium channels. Aldosterone‑induced CACNA1H protein expression could be abrogated by the EGFR inhibitor AG1478. Furthermore, inhibition of T‑type calcium channels with mibefradil or ML218 reduced diameter, volume and BNP levels in HL‑1 cells. In conclusion the MR regulates EGFR and CACNA1H expression, which has an efect on HL‑1 cell diameter, and the extent of this regulation seems to depend on the SNP‑216 (G/T) genotype.
    [Show full text]
  • Aquaporin Channels in the Heart—Physiology and Pathophysiology
    International Journal of Molecular Sciences Review Aquaporin Channels in the Heart—Physiology and Pathophysiology Arie O. Verkerk 1,2,* , Elisabeth M. Lodder 2 and Ronald Wilders 1 1 Department of Medical Biology, Amsterdam University Medical Centers, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands; [email protected] 2 Department of Experimental Cardiology, Amsterdam University Medical Centers, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands; [email protected] * Correspondence: [email protected]; Tel.: +31-20-5664670 Received: 29 March 2019; Accepted: 23 April 2019; Published: 25 April 2019 Abstract: Mammalian aquaporins (AQPs) are transmembrane channels expressed in a large variety of cells and tissues throughout the body. They are known as water channels, but they also facilitate the transport of small solutes, gasses, and monovalent cations. To date, 13 different AQPs, encoded by the genes AQP0–AQP12, have been identified in mammals, which regulate various important biological functions in kidney, brain, lung, digestive system, eye, and skin. Consequently, dysfunction of AQPs is involved in a wide variety of disorders. AQPs are also present in the heart, even with a specific distribution pattern in cardiomyocytes, but whether their presence is essential for proper (electro)physiological cardiac function has not intensively been studied. This review summarizes recent findings and highlights the involvement of AQPs in normal and pathological cardiac function. We conclude that AQPs are at least implicated in proper cardiac water homeostasis and energy balance as well as heart failure and arsenic cardiotoxicity. However, this review also demonstrates that many effects of cardiac AQPs, especially on excitation-contraction coupling processes, are virtually unexplored.
    [Show full text]
  • Potassium Channels in Epilepsy
    Downloaded from http://perspectivesinmedicine.cshlp.org/ on September 28, 2021 - Published by Cold Spring Harbor Laboratory Press Potassium Channels in Epilepsy Ru¨diger Ko¨hling and Jakob Wolfart Oscar Langendorff Institute of Physiology, University of Rostock, Rostock 18057, Germany Correspondence: [email protected] This review attempts to give a concise and up-to-date overview on the role of potassium channels in epilepsies. Their role can be defined from a genetic perspective, focusing on variants and de novo mutations identified in genetic studies or animal models with targeted, specific mutations in genes coding for a member of the large potassium channel family. In these genetic studies, a demonstrated functional link to hyperexcitability often remains elusive. However, their role can also be defined from a functional perspective, based on dy- namic, aggravating, or adaptive transcriptional and posttranslational alterations. In these cases, it often remains elusive whether the alteration is causal or merely incidental. With 80 potassium channel types, of which 10% are known to be associated with epilepsies (in humans) or a seizure phenotype (in animals), if genetically mutated, a comprehensive review is a challenging endeavor. This goal may seem all the more ambitious once the data on posttranslational alterations, found both in human tissue from epilepsy patients and in chronic or acute animal models, are included. We therefore summarize the literature, and expand only on key findings, particularly regarding functional alterations found in patient brain tissue and chronic animal models. INTRODUCTION TO POTASSIUM evolutionary appearance of voltage-gated so- CHANNELS dium (Nav)andcalcium (Cav)channels, Kchan- nels are further diversified in relation to their otassium (K) channels are related to epilepsy newer function, namely, keeping neuronal exci- Psyndromes on many different levels, ranging tation within limits (Anderson and Greenberg from direct control of neuronal excitability and 2001; Hille 2001).
    [Show full text]
  • The Role of TRP Channels in the Metastatic Cascade
    pharmaceuticals Review The Role of TRP Channels in the Metastatic Cascade Benedikt Fels *, Etmar Bulk, Zoltán Peth˝oand Albrecht Schwab Institut für Physiologie II, Robert-Koch-Str. 27b, 48149 Münster, Germany; [email protected] (E.B.); [email protected] (Z.P.); [email protected] (A.S.) * Correspondence: [email protected]; Tel.: +49-251-83-55336 Received: 20 April 2018; Accepted: 16 May 2018; Published: 17 May 2018 Abstract: A dysregulated cellular Ca2+ homeostasis is involved in multiple pathologies including cancer. Changes in Ca2+ signaling caused by altered fluxes through ion channels and transporters (the transportome) are involved in all steps of the metastatic cascade. Cancer cells thereby “re-program” and “misuse” the cellular transportome to regulate proliferation, apoptosis, metabolism, growth factor signaling, migration and invasion. Cancer cells use their transportome to cope with diverse environmental challenges during the metastatic cascade, like hypoxic, acidic and mechanical cues. Hence, ion channels and transporters are key modulators of cancer progression. This review focuses on the role of transient receptor potential (TRP) channels in the metastatic cascade. After briefly introducing the role of the transportome in cancer, we discuss TRP channel functions in cancer cell migration. We highlight the role of TRP channels in sensing and transmitting cues from the tumor microenvironment and discuss their role in cancer cell invasion. We identify open questions concerning the role of TRP channels in circulating tumor cells and in the processes of intra- and extravasation of tumor cells. We emphasize the importance of TRP channels in different steps of cancer metastasis and propose cancer-specific TRP channel blockade as a therapeutic option in cancer treatment.
    [Show full text]
  • Emerging Roles for Multifunctional Ion Channel Auxiliary Subunits in Cancer T ⁎ Alexander S
    Cell Calcium 80 (2019) 125–140 Contents lists available at ScienceDirect Cell Calcium journal homepage: www.elsevier.com/locate/ceca Emerging roles for multifunctional ion channel auxiliary subunits in cancer T ⁎ Alexander S. Hawortha,b, William J. Brackenburya,b, a Department of Biology, University of York, Heslington, York, YO10 5DD, UK b York Biomedical Research Institute, University of York, Heslington, York, YO10 5DD, UK ARTICLE INFO ABSTRACT Keywords: Several superfamilies of plasma membrane channels which regulate transmembrane ion flux have also been Auxiliary subunit shown to regulate a multitude of cellular processes, including proliferation and migration. Ion channels are Cancer typically multimeric complexes consisting of conducting subunits and auxiliary, non-conducting subunits. Calcium channel Auxiliary subunits modulate the function of conducting subunits and have putative non-conducting roles, further Chloride channel expanding the repertoire of cellular processes governed by ion channel complexes to processes such as trans- Potassium channel cellular adhesion and gene transcription. Given this expansive influence of ion channels on cellular behaviour it Sodium channel is perhaps no surprise that aberrant ion channel expression is a common occurrence in cancer. This review will − focus on the conducting and non-conducting roles of the auxiliary subunits of various Ca2+,K+,Na+ and Cl channels and the burgeoning evidence linking such auxiliary subunits to cancer. Several subunits are upregu- lated (e.g. Cavβ,Cavγ) and downregulated (e.g. Kvβ) in cancer, while other subunits have been functionally implicated as oncogenes (e.g. Navβ1,Cavα2δ1) and tumour suppressor genes (e.g. CLCA2, KCNE2, BKγ1) based on in vivo studies. The strengthening link between ion channel auxiliary subunits and cancer has exposed these subunits as potential biomarkers and therapeutic targets.
    [Show full text]
  • Variants in the KCNE1 Or KCNE3 Gene and Risk of Ménière’S Disease: a Meta-Analysis
    Journal of Vestibular Research 25 (2015) 211–218 211 DOI 10.3233/VES-160569 IOS Press Variants in the KCNE1 or KCNE3 gene and risk of Ménière’s disease: A meta-analysis Yuan-Jun Li, Zhan-Guo Jin and Xian-Rong Xu∗ The Center of Clinical Aviation Medicine, General Hospital of Air Force, Beijing, China Received 1 August 2015 Accepted 8 December 2015 Abstract. BACKGROUND: Ménière’s disease (MD) is defined as an idiopathic disorder of the inner ear characterized by the triad of tinnitus, vertigo, and sensorineural hearing loss. Although many studies have evaluated the association between variants in the KCNE1 or KCNE3 gene and MD risk, debates still exist. OBJECTIVE: Our aim is to evaluate the association between KCNE gene variants, including KCNE1 rs1805127 and KCNE3 rs2270676, and the risk of MD by a systematic review. METHODS: We searched the literature in PubMed, SCOPUS and EMBASE through May 2015. We calculated pooled odds ra- tios (OR) and 95% confidence intervals (CIs) using a fixed-effects model or a random-effects model for the risk to MD associated with different KCNE gene variants. The heterogeneity assumption decided the effect model. RESULTS: A total of three relevant studies, with 302 MD cases and 515 controls, were included in this meta-analysis. The results indicated that neither the KCNE1 rs1805127 variant (for G vs. A: OR = 0.724, 95%CI 0.320, 1.638, P = 0.438), nor the KCNE3 rs2270676 variant (for T vs. C: OR = 0.714, 95%CI 0.327, 1.559, P = 0.398) was associated with MD risk.
    [Show full text]
  • Src Regulation of Cx43 Phosphorylation and Gap Junction Turnover
    biomolecules Article Src Regulation of Cx43 Phosphorylation and Gap Junction Turnover Joell L. Solan 1 and Paul D. Lampe 1,2,* 1 Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; [email protected] 2 Department of Global Health, Pathobiology Program, University of Washington, Seattle, WA 98109, USA * Correspondence: [email protected] Received: 27 October 2020; Accepted: 22 November 2020; Published: 24 November 2020 Abstract: The gap junction protein Connexin43 (Cx43) is highly regulated by phosphorylation at over a dozen sites by probably at least as many kinases. This Cx43 “kinome” plays an important role in gap junction assembly and turnover. We sought to gain a better understanding of the interrelationship of these phosphorylation events particularly related to src activation and Cx43 turnover. Using state-of-the-art live imaging methods, specific inhibitors and many phosphorylation-status specific antibodies, we found phospho-specific domains in gap junction plaques and show evidence that multiple pathways of disassembly exist and can be regulated at the cellular and subcellular level. We found Src activation promotes formation of connexisomes (internalized gap junctions) in a process involving ERK-mediated phosphorylation of S279/282. Proteasome inhibition dramatically and rapidly restored gap junctions in the presence of Src and led to dramatic changes in the Cx43 phospho-profile including to increased Y247, Y265, S279/282, S365, and S373 phosphorylation. Lysosomal inhibition, on the other hand, nearly eliminated phosphorylation on Y247 and Y265 and reduced S368 and S373 while increasing S279/282 phosphorylation levels. We present a model of gap junction disassembly where multiple modes of disassembly are regulated by phosphorylation and can have differential effects on cellular signaling.
    [Show full text]
  • Kvlqt1, a Voltage-Gated Potassium Channel Responsible for Human Cardiac Arrhythmias
    Proc. Natl. Acad. Sci. USA Vol. 94, pp. 4017–4021, April 1997 Medical Sciences KvLQT1, a voltage-gated potassium channel responsible for human cardiac arrhythmias WEN-PIN YANG,PAUL C. LEVESQUE,WAYNE A. LITTLE,MARY LEE CONDER,FOUAD Y. SHALABY, AND MICHAEL A. BLANAR* Department of Cardiovascular Drug Discovery, Bristol–Myers Squibb Pharmaceutical Research Institute, Route 206 and Provinceline Road, Princeton, NJ 08543-4000 Communicated by Leon E. Rosenberg, Bristol–Myers Squibb Pharmaceutical Research Institute, Princeton, NJ, January 29, 1997 (received for review November 13, 1996) ABSTRACT The clinical features of long QT syndrome amplifying adult human cardiac and pancreas cDNA libraries result from episodic life-threatening cardiac arrhythmias, or Marathon-Ready cDNAs (CLONTECH) using primers specifically the polymorphic ventricular tachycardia torsades derived from the S1 and S2 region of the partial KVLQT1 de pointes. KVLQT1 has been established as the human cDNA sequence described previously (1). PCR products were chromosome 11-linked gene responsible for more than 50% of gel-purified, subcloned, and sequenced. Primers subsequently inherited long QT syndrome. Here we describe the cloning of were designed from the sequences containing the candidate 59 a full-length KVLQT1 cDNA and its functional expression. end of KVLQT1 and were used for a second round of 59 RACE. KVLQT1 encodes a 676-amino acid polypeptide with struc- This procedure was repeated until no additional 59 end cDNA tural characteristics similar to voltage-gated potassium chan- sequence was obtained. Random-primed 32P-labeled DNA nels. Expression of KvLQT1 in Xenopus oocytes and in human probes containing specific regions of KVLQT1 sequence were embryonic kidney cells elicits a rapidly activating, K1- used for screening of cDNA libraries and Northern blot selective outward current.
    [Show full text]
  • Control Qpatch Htx Multi-Hole
    41577_Poster 170x110.qxd:Poster 170x110 07/04/10 8:52 Side 1 SOPHION BIOSCIENCE A/S SOPHION BIOSCIENCE, INC. SOPHION JAPAN Baltorpvej 154 675 US Highway One 1716-6, Shimmachi ENHANCING THROUGHPUT WITH MULTIPLE DK-2750 Ballerup North Brunswick, NJ 08902 Takasaki-shi, Gumma 370-1301 DENMARK USA JAPAN [email protected] Phone: +1 732 745 0221 Phone: +81 274 50 8388 CELL LINES PER WELL WITH THE QPATCH HTX www.sophion.com www.sophion.com www.sophion.com HERVØR LYKKE OLSEN l DORTHE NIELSEN l MORTEN SUNESEN QPATCH HTX MULTI-HOLE: TEMPORAL CURRENT QPATCH HTX MULTI-HOLE: PHARMACOLOGICAL SEPARATION BASED ON DISCRETE RECORDING SEPARATION BASED ON ION CHANNEL INHIBITORS TIME WINDOWS KvLQT1/minK (KCNQ1/KCNE1) INTRODUCTION Kv1.5 (KCNA5) ABRaw traces (A) and Hill plot (B) for XE991. ABC hERG and Nav1.5 blocked by E-4031 and The QPatch HTX automated patch clamp technology was developed to 1) increase throughput in ion channel drug TTX, respectively. screening by parallel operation of 48 multi-hole patch clamp sites, each comprising 10 individual patch clamp holes, in a single measurements site on a QPlate X, and 2) diminish problems with low-expressing cell lines. Thus, parallel recording from 10 cells represents a 10-fold signal amplification, and it increases the success rate at each site substantially. To further increase throughput we explored the possibility of simultaneous recording of a number of ion channel currents. IC50 (μM) XE991 Two or three cell lines, each expressing a specific ion channel, were applied at each site simultaneously. The ion channel Measured Literature currents were separated temporally or pharmacologically by proper choices of voltage protocols or ion channel KvLQT1 3.5±1.0 (n=12) 1-6 (Ref.
    [Show full text]
  • Supplemental Table 1. Complete Gene Lists and GO Terms from Figure 3C
    Supplemental Table 1. Complete gene lists and GO terms from Figure 3C. Path 1 Genes: RP11-34P13.15, RP4-758J18.10, VWA1, CHD5, AZIN2, FOXO6, RP11-403I13.8, ARHGAP30, RGS4, LRRN2, RASSF5, SERTAD4, GJC2, RHOU, REEP1, FOXI3, SH3RF3, COL4A4, ZDHHC23, FGFR3, PPP2R2C, CTD-2031P19.4, RNF182, GRM4, PRR15, DGKI, CHMP4C, CALB1, SPAG1, KLF4, ENG, RET, GDF10, ADAMTS14, SPOCK2, MBL1P, ADAM8, LRP4-AS1, CARNS1, DGAT2, CRYAB, AP000783.1, OPCML, PLEKHG6, GDF3, EMP1, RASSF9, FAM101A, STON2, GREM1, ACTC1, CORO2B, FURIN, WFIKKN1, BAIAP3, TMC5, HS3ST4, ZFHX3, NLRP1, RASD1, CACNG4, EMILIN2, L3MBTL4, KLHL14, HMSD, RP11-849I19.1, SALL3, GADD45B, KANK3, CTC- 526N19.1, ZNF888, MMP9, BMP7, PIK3IP1, MCHR1, SYTL5, CAMK2N1, PINK1, ID3, PTPRU, MANEAL, MCOLN3, LRRC8C, NTNG1, KCNC4, RP11, 430C7.5, C1orf95, ID2-AS1, ID2, GDF7, KCNG3, RGPD8, PSD4, CCDC74B, BMPR2, KAT2B, LINC00693, ZNF654, FILIP1L, SH3TC1, CPEB2, NPFFR2, TRPC3, RP11-752L20.3, FAM198B, TLL1, CDH9, PDZD2, CHSY3, GALNT10, FOXQ1, ATXN1, ID4, COL11A2, CNR1, GTF2IP4, FZD1, PAX5, RP11-35N6.1, UNC5B, NKX1-2, FAM196A, EBF3, PRRG4, LRP4, SYT7, PLBD1, GRASP, ALX1, HIP1R, LPAR6, SLITRK6, C16orf89, RP11-491F9.1, MMP2, B3GNT9, NXPH3, TNRC6C-AS1, LDLRAD4, NOL4, SMAD7, HCN2, PDE4A, KANK2, SAMD1, EXOC3L2, IL11, EMILIN3, KCNB1, DOK5, EEF1A2, A4GALT, ADGRG2, ELF4, ABCD1 Term Count % PValue Genes regulation of pathway-restricted GDF3, SMAD7, GDF7, BMPR2, GDF10, GREM1, BMP7, LDLRAD4, SMAD protein phosphorylation 9 6.34 1.31E-08 ENG pathway-restricted SMAD protein GDF3, SMAD7, GDF7, BMPR2, GDF10, GREM1, BMP7, LDLRAD4, phosphorylation
    [Show full text]