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Sugita J, Fujiu K. Emerging Function of Cardiac Macrophages Ushers in a New Era for the Electrophysiology of the Heart. Circ Rep 2019; 1:558-563. [PMID: 33693101 PMCID: PMC7897688 DOI: 10.1253/circrep.cr-19-0103] [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] [Indexed: 11/25/2022] Open
Abstract
Maintaining a coordinated heart rhythm is essential for maintaining the heart’s pumping function and blood circulation. Every heartbeat is generated by electrical impulse propagation that is passing through gap junctions, which are composed of connexin proteins. In mammalian hearts, Cx43, Cx40, Cx45, and Cx30.2 are expressed and regulated by post-translational modification. Cardiac macrophages account for only a small number of total heart cells, but they reside all around the heart. They are primarily established prenatally, and they arise from embryonic yolk sac progenitors. Recently, increasing attention has been directed toward novel roles for cardiac resident macrophages, especially in the heart’s electrical impulse conduction. Here, we provide an overview of the recent findings on connexins, with a focus on the emerging function of cardiac macrophages, and we discuss the future directions of treatment for heart disease.
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Affiliation(s)
- Junichi Sugita
- Department of Cardiovascular Medicine, the University of Tokyo Tokyo Japan
| | - Katsuhito Fujiu
- Department of Cardiovascular Medicine, the University of Tokyo Tokyo Japan.,Department of Advanced Cardiology, the University of Tokyo Tokyo Japan
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Ji X, Chou X, Ge Z, Ding F, Gao H, Wu Q. Benzo[a
]pyrene-decreased gap junctional intercellular communication via calcium/calmodulin signaling increases apoptosis in TM4 cells. J Appl Toxicol 2018; 38:1091-1103. [DOI: 10.1002/jat.3618] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 02/07/2018] [Accepted: 02/07/2018] [Indexed: 12/12/2022]
Affiliation(s)
- Xiaoli Ji
- School of Public Health; Fudan University and Key Laboratory of Public Health Safety, Ministry of Education; 130 Dong An Road Shanghai 200032 China
| | - Xin Chou
- School of Public Health; Fudan University and Key Laboratory of Public Health Safety, Ministry of Education; 130 Dong An Road Shanghai 200032 China
| | - Zehe Ge
- School of Public Health; Fudan University and Key Laboratory of Public Health Safety, Ministry of Education; 130 Dong An Road Shanghai 200032 China
| | - Fan Ding
- School of Public Health; Fudan University and Key Laboratory of Public Health Safety, Ministry of Education; 130 Dong An Road Shanghai 200032 China
| | - Hui Gao
- School of Public Health; Fudan University and Key Laboratory of Public Health Safety, Ministry of Education; 130 Dong An Road Shanghai 200032 China
| | - Qing Wu
- School of Public Health; Fudan University and Key Laboratory of Public Health Safety, Ministry of Education; 130 Dong An Road Shanghai 200032 China
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Meens MJ, Kwak BR, Duffy HS. Role of connexins and pannexins in cardiovascular physiology. Cell Mol Life Sci 2015; 72:2779-92. [PMID: 26091747 PMCID: PMC11113959 DOI: 10.1007/s00018-015-1959-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 06/11/2015] [Indexed: 12/26/2022]
Abstract
Connexins and pannexins form connexons, pannexons and membrane channels, which are critically involved in many aspects of cardiovascular physiology. For that reason, a vast number of studies have addressed the role of connexins and pannexins in the arterial and venous systems as well as in the heart. Moreover, a role for connexins in lymphatics has recently also been suggested. This review provides an overview of the current knowledge regarding the involvement of connexins and pannexins in cardiovascular physiology.
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Affiliation(s)
- Merlijn J. Meens
- Department of Pathology and Immunology, University of Geneva, Rue Michel-Servet 1, 1211 Geneva 4, Switzerland
- Department of Medical Specializations-Cardiology, University of Geneva, Geneva, Switzerland
| | - Brenda R. Kwak
- Department of Pathology and Immunology, University of Geneva, Rue Michel-Servet 1, 1211 Geneva 4, Switzerland
- Department of Medical Specializations-Cardiology, University of Geneva, Geneva, Switzerland
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BIERBOWER SONYAM, COOPER ROBINL. The Mechanistic Action of Carbon Dioxide on a Neural Circuit and NMJ Communication. ACTA ACUST UNITED AC 2013; 319:340-54. [DOI: 10.1002/jez.1798] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 03/13/2013] [Accepted: 04/01/2013] [Indexed: 11/07/2022]
Affiliation(s)
- SONYA M. BIERBOWER
- Department of Biology and Center for Muscle Biology; University of Kentucky; Lexington; Kentucky
| | - ROBIN L. COOPER
- Department of Biology and Center for Muscle Biology; University of Kentucky; Lexington; Kentucky
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Baierlein B, Thurow AL, Atwood HL, Cooper RL. Membrane potentials, synaptic responses, neuronal circuitry, neuromodulation and muscle histology using the crayfish: student laboratory exercises. J Vis Exp 2011:2322. [PMID: 21304459 PMCID: PMC3733577 DOI: 10.3791/2322] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The purpose of this report is to help develop an understanding of the effects caused by ion gradients across a biological membrane. Two aspects that influence a cell's membrane potential and which we address in these experiments are: (1) Ion concentration of K+ on the outside of the membrane, and (2) the permeability of the membrane to specific ions. The crayfish abdominal extensor muscles are in groupings with some being tonic (slow) and others phasic (fast) in their biochemical and physiological phenotypes, as well as in their structure; the motor neurons that innervate these muscles are correspondingly different in functional characteristics. We use these muscles as well as the superficial, tonic abdominal flexor muscle to demonstrate properties in synaptic transmission. In addition, we introduce a sensory-CNS-motor neuron-muscle circuit to demonstrate the effect of cuticular sensory stimulation as well as the influence of neuromodulators on certain aspects of the circuit. With the techniques obtained in this exercise, one can begin to answer many questions remaining in other experimental preparations as well as in physiological applications related to medicine and health. We have demonstrated the usefulness of model invertebrate preparations to address fundamental questions pertinent to all animals.
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Zhou Y, Yang W, Lurtz MM, Chen Y, Jiang J, Huang Y, Louis CF, Yang JJ. Calmodulin mediates the Ca2+-dependent regulation of Cx44 gap junctions. Biophys J 2009; 96:2832-48. [PMID: 19348766 DOI: 10.1016/j.bpj.2008.12.3941] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2008] [Revised: 12/07/2008] [Accepted: 12/23/2008] [Indexed: 10/20/2022] Open
Abstract
We have shown previously that the Ca2+-dependent inhibition of lens epithelial cell-to-cell communication is mediated in part by the direct association of calmodulin (CaM) with connexin43 (Cx43), the major connexin in these cells. We now show that elevation of [Ca2+](i) in HeLa cells transfected with the lens fiber cell gap junction protein sheep Cx44 also results in the inhibition of cell-to-cell dye transfer. A peptide comprising the putative CaM binding domain (aa 129-150) of the intracellular loop region of this connexin exhibited a high affinity, stoichiometric interaction with Ca2+-CaM. NMR studies indicate that the binding of Cx44 peptide to CaM reflects a classical embracing mode of interaction. The interaction is an exothermic event that is both enthalpically and entropically driven in which electrostatic interactions play an important role. The binding of the Cx44 peptide to CaM increases the CaM intradomain cooperativity and enhances the Ca2+-binding affinities of the C-domain of CaM more than twofold by slowing the rate of Ca2+ release from the complex. Our data suggest a common mechanism by which the Ca2+-dependent inhibition of the alpha-class of gap junction proteins is mediated by the direct association of an intracellular loop region of these proteins with Ca2+-CaM.
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Affiliation(s)
- Yubin Zhou
- Department of Chemistry, Georgia State University, Atlanta, Georgia 30303, USA
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Abstract
The mechanism by which intracellular Ca(2+) concentration ([Ca(2+)](i)) regulates the permeability of gap junctions composed of connexin43 (Cx43) was investigated in HeLa cells stably transfected with this connexin. Extracellular addition of Ca(2+) in the presence of the Ca(2+) ionophore ionomycin produced a sustained elevation in [Ca(2+)](i) that resulted in an inhibition of the cell-to-cell transfer of the fluorescent dye Alexa fluor 594 (IC(50) of 360 nM Ca(2+)). The Ca(2+) dependency of this inhibition of Cx43 gap junctional permeability is very similar to that described in sheep lens epithelial cell cultures that express the three sheep lens connexins (Cx43, Cx44, and Cx49). The intracellular Ca(2+)-mediated decrease in cell-to-cell dye transfer was prevented by an inhibitor of calmodulin action but not by inhibitors of Ca(2+)/calmodulin-dependent protein kinase II or protein kinase C. In experiments that used HeLa cells transfected with a Cx43 COOH-terminus truncation mutant (Cx43(Delta257)), cell-to-cell coupling was similarly decreased by an elevation of [Ca(2+)](i) (IC(50) of 310 nM Ca(2+)) and similarly prevented by the addition of an inhibitor of calmodulin. These data indicate that physiological concentrations of [Ca(2+)](i) regulate the permeability of Cx43 in a calmodulin-dependent manner that does not require the major portion of the COOH terminus of Cx43.
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Affiliation(s)
- Monica M Lurtz
- Department of Cell Biology and Neuroscience, University of California, Riverside, CA 92521, USA.
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Connexin Interacting Proteins. HEART CELL COUPLING AND IMPULSE PROPAGATION IN HEALTH AND DISEASE 2002. [DOI: 10.1007/978-1-4615-1155-7_2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
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Churchill GC, Lurtz MM, Louis CF. Ca(2+) regulation of gap junctional coupling in lens epithelial cells. Am J Physiol Cell Physiol 2001; 281:C972-81. [PMID: 11502574 DOI: 10.1152/ajpcell.2001.281.3.c972] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The quantitative effects of Ca(2+) signaling on gap junctional coupling in lens epithelial cells have been determined using either the spread of Mn(2+) that is imaged by its ability to quench the fluorescence of fura 2 or the spread of the fluorescent dye Alexa Fluor 594. Gap junctional coupling was unaffected by a mechanically stimulated cell-to-cell Ca(2+) wave. Furthermore, when cytosolic Ca(2+) concentration (Ca) increased after the addition of the agonist ATP, coupling was unaffected during the period that Ca was maximal. However, coupling decreased transiently approximately 5-10 min after agonist addition when Ca returned to resting levels, indicating that this transient decrease in coupling was unlikely due to a direct action of Ca on gap junctions. An increase in Ca mediated by the ionophore ionomycin that was sustained for several minutes resulted in a more rapid and sustained decrease in coupling (IC(50) ~300 nM Ca(2+), Hill coefficient of 4), indicating that an increase in Ca alone could regulate gap junctions. Thus Ca increases that occurred during agonist stimulation and cell-to-cell Ca(2+) waves were too transient to mediate a sustained uncoupling of lens epithelial cells.
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Affiliation(s)
- G C Churchill
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, USA
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Yahuaca P, Ek-Vitorin JF, Rush P, Delmar M, Taffet SM. Identification of a protein kinase activity that phosphorylates connexin43 in a pH-dependent manner. Braz J Med Biol Res 2000; 33:399-406. [PMID: 10775304 DOI: 10.1590/s0100-879x2000000400005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The carboxyl-terminal (CT) domain of connexin43 (Cx43) has been implicated in both hormonal and pH-dependent gating of the gap junction channel. An in vitro assay was utilized to determine whether the acidification of cell extracts results in the activation of a protein kinase that can phosphorylate the CT domain. A glutathione S-transferase (GST)-fusion protein was bound to Sephadex beads and used as a target for protein kinase phosphorylation. A protein extract produced from sheep heart was allowed to bind to the fusion protein-coated beads. The bound proteins were washed and then incubated with 32P-ATP. Phosphorylation was assessed after the proteins were resolved by SDS-PAGE. Incubation at pH 7.5 resulted in a minimal amount of phosphorylation while incubation at pH 6.5 resulted in significant phosphorylation reaction. Maximal activity was achieved when both the binding and kinase reactions were performed at pH 6.5. The protein kinase activity was stronger when the incubations were performed with manganese rather than magnesium. Mutants of Cx43 which lack the serines between amino acids 364-374 could not be phosphorylated in the in vitro kinase reaction, indicating that this is a likely target of this reaction. These results indicate that there is a protein kinase activity in cells that becomes more active at lower pH and can phosphorylate Cx43.
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Affiliation(s)
- P Yahuaca
- Department of Pharmacology, SUNY Health Science Center at Syracuse, Syracuse, NY 13210, USA
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Abstract
Gap junctions are highly conductive channels that allow the direct transfer of intracellular messengers such as Ca2+ and inositol triphosphate (IP3) between interconnected cells. In brain, astrocytes are coupled extensively by gap junctions. We found here that gap junctions among astrocytes in acutely prepared brain slices as well as in culture remained open during ischemic conditions. Uncoupling first occurred after the terminal loss of plasma membrane integrity. Gap junctions therefore may link ischemic astrocytes in an evolving infarct with the surroundings. The free exchange of intracellular messengers between dying and potentially viable astrocytes might contribute to secondary expansion of ischemic lesions.
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Cotrina ML, Kang J, Lin JH, Bueno E, Hansen TW, He L, Liu Y, Nedergaard M. Astrocytic gap junctions remain open during ischemic conditions. J Neurosci 1998; 18:2520-37. [PMID: 9502812 PMCID: PMC6793088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/1997] [Revised: 12/22/1997] [Accepted: 12/29/1997] [Indexed: 02/06/2023] Open
Abstract
Gap junctions are highly conductive channels that allow the direct transfer of intracellular messengers such as Ca2+ and inositol triphosphate (IP3) between interconnected cells. In brain, astrocytes are coupled extensively by gap junctions. We found here that gap junctions among astrocytes in acutely prepared brain slices as well as in culture remained open during ischemic conditions. Uncoupling first occurred after the terminal loss of plasma membrane integrity. Gap junctions therefore may link ischemic astrocytes in an evolving infarct with the surroundings. The free exchange of intracellular messengers between dying and potentially viable astrocytes might contribute to secondary expansion of ischemic lesions.
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Affiliation(s)
- M L Cotrina
- Department of Cell Biology, New York Medical College, Valhalla, New York 10595, USA
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Abstract
Pairs of electrically coupled glomus cells from rat carotid bodies were impaled with microelectrodes. In the current clamp mode, intracellular stimulation and recording established the coupling coefficient (KC), across the intercellular junctions. About 80% of 26 pairs uncoupled during exposure to 9.45 mM [Ca2+]o, and about 72% of 18 pairs showed the same effect during applications of ionophore A23187. During superfusion with zero [Ca2+]o and EGTA, about 73% of 40 pairs of cells became more tightly coupled. Similar results (71%) were obtained during exposure of 42 cell pairs to BAPTA/AM, a membrane-permeant calcium chelator. Thus, [Ca2+]i seemed to play a significant a role in glomus cell intercellular communication. A23187 and BAPTA/AM, dissolved in DMSO, tended to reduce intercellular coupling during prolonged exposures of the preparations to this solvent. Consequently, the effects elicited by A23187 and BAPTA/AM were superimposed on a coupling effect produced by DMSO.
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Affiliation(s)
- V Abudara
- Department of Physiology, University of Utah School of Medicine, Salt Lake City 84108, USA
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Spray DC. Physiological Properties of Gap Junction Channels in the Nervous System. NEUROSCIENCE INTELLIGENCE UNIT 1996. [DOI: 10.1007/978-3-662-21935-5_3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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DAI JIDA, COSTELLO MJOSEPH, GILBERT LAWRENCEI. The prothoracic glands ofManduca sexta:a microscopic analysis of gap junctions and intercellular bridges. INVERTEBR REPROD DEV 1994. [DOI: 10.1080/07924259.1994.9672375] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Moreno AP, Spray DC, Ramón F. Humoral factors reduce gap junction sensitivity to cytoplasmic pH. I. Organ ablation studies. THE AMERICAN JOURNAL OF PHYSIOLOGY 1991; 260:C1028-38. [PMID: 2035611 DOI: 10.1152/ajpcell.1991.260.5.c1028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The sensitivity of gap junctions connecting crayfish lateral axons to uncoupling by axoplasmic acidification was studied after altering the hormonal balance of animals by 1) ablation of eyestalks or sinus glands or 2) inducing long-lasting defensive posturing behavior (stress). Internal pH (pHi) was measured with microelectrodes, and junctional resistance (Rj) was calculated from input and transfer resistances. In isolated nerve cords from intact animals, the maximal Rj (Rjmax) reached after acidification varied diurnally (Rjmax approximately 10 and 0.6 M omega at 0900 and 1800 h, respectively). Basal Rj (20-30 k omega) did not change during the 24-h period. Organ ablation (eyestalks or sinus glands) or stress rendered gap junctions less sensitive to uncoupling by low pHi within 1 h or 2 days; recovery toward control values had different time courses. The reduced pH sensitivity of crayfish junctions seen after eyestalk ablation is attributable to stress in its early phase (lasting 1-2 days) and to ablation of the endocrine organs in its late phase (2-7 days). No striking structural differences accompanied these changes, indicating that the altered properties are not due to major changes in gap junction expression.
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Affiliation(s)
- A P Moreno
- Departmento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados, Mexico DF
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Moreno AP, Arellano RO, Rivera A, Ramón F. Humoral factors reduce gap junction sensitivity to cytoplasmic pH. II. In vitro manipulations. THE AMERICAN JOURNAL OF PHYSIOLOGY 1991; 260:C1039-45. [PMID: 2035612 DOI: 10.1152/ajpcell.1991.260.5.c1039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Our previous studies demonstrated a diurnal rhythm in the response of gap junctions between crayfish giant axons to acidification and that the response was reduced after eyestalk ablation, sinus gland removal, or visual stress. In this paper we describe experiments to test whether compounds in the circulating hemolymph were responsible for modulation of the responsiveness gap junction channels to intracellular pH. In axons from destalked animals in which the hemolymph had been replaced with normal saline, the maximal junctional resistance after acidification (Rjmax) reached control values. In contrast, Rjmax reached only 30% of control after acidification in axons from animals that had been destalked but not perfused. Hemolymph drawn after eyestalk ablation was tested on axons from control animals. Treatment with hemolymph drawn 1 day after destalking resulted in control Rjmax values, while treatment with hemolymph drawn 7 days after destalking resulted in Rjmax values of only 5-40%. Similarly, pretreatment for 1 h with 100 microM ecdysterone resulted in low Rjmax values. These experimental results suggest that a circulating compound, most likely ecdysterone or a related molecule, regulates the physiological properties of gap junctions from crayfish lateral axons.
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Affiliation(s)
- A P Moreno
- Departamento de Fisiología Biofísica, Centro de Investigación y Estudios Avanzados, Mexico DF
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Musil LS, Goodenough DA. Gap junctional intercellular communication and the regulation of connexin expression and function. Curr Opin Cell Biol 1990; 2:875-80. [PMID: 1964569 DOI: 10.1016/0955-0674(90)90086-t] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- L S Musil
- Department of Anatomy and Cellular Biology, Harvard Medical School, Boston, Massachusetts
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Goffeau A, Ghislain M, Navarre C, Purnelle B, Supply P. Novel transport ATPases in yeast. BIOCHIMICA ET BIOPHYSICA ACTA 1990; 1018:200-2. [PMID: 2144187 DOI: 10.1016/0005-2728(90)90248-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- A Goffeau
- Université de Louvain, Unité de Biochimie Physiologique, Louvain-la-Neuve, Belgium
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