title: Functional consequences of co-expressing connexin40 or connexin45 with connexin43 on intercellular electrical coupling.
abstract: The functional characteristics of the co-expression of connexin43, connexin40, and connexin45 proteins in human myocardium are thought to play an important role in governing normal propagation of the cardiac electrical impulse and in generating the myocardial substrate for some arrhythmias and conduction disturbances. A rat liver epithelial cell line, that endogenously expresses connexin43, was used to induce also expression of connexin40 or connexin45 after stable transfection using an inducible ecdysone system. Electrical coupling was estimated from measurement of the input resistance of transfected cells using an intracellular microelectrode to inject current and record changes to membrane potential. However, varied expression of the transfected connexin40 or connexin45 did not change electrical coupling, although connexin43/40 co-expression led to better coupling than connexin43/45 co-expression. Quantification of endogenous connexin43 expression, at both mRNA and protein levels, showed that it was altered in a manner dependent on the transfected connexin isotype. The data using rat liver epithelial cells indicate an increased electrical coupling upon expression of connexin40 and connexin43 but decreased coupling with connexin45 and connexin43 co-expression.
authors.affiliation: Myocardial Function, National Heart and Lung Institute, Imperial College London, London, UK. Electronic address: neilmjthomas@gmail.com.
authors.forename: Neil M
authors.initials: NM
authors.lastname: Thomas
authors.affiliation: The Whittington Hospital NHS Trust, London, UK. Electronic address: rosaire.gray@nhs.net.
authors.forename: Rosaire
authors.initials: R
authors.lastname: Gray
authors.affiliation: School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, UK. Electronic address: chris.fry@bristol.ac.uk.
authors.forename: Christopher H
authors.initials: CH
authors.lastname: Fry
authors.affiliation: Myocardial Function, National Heart and Lung Institute, Imperial College London, London, UK. Electronic address: Thomas.Desplantez@ihu-liryc.fr.
authors.forename: Thomas
authors.initials: T
authors.lastname: Desplantez
authors.affiliation: Myocardial Function, National Heart and Lung Institute, Imperial College London, London, UK. Electronic address: n.peters@imperial.ac.uk.
authors.forename: Nicholas S
authors.initials: NS
authors.lastname: Peters
authors.affiliation: Myocardial Function, National Heart and Lung Institute, Imperial College London, London, UK. Electronic address: n.severs@imperial.ac.uk.
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Severs
authors.affiliation: Myocardial Function, National Heart and Lung Institute, Imperial College London, London, UK. Electronic address: k.t.macleod@imperial.ac.uk.
authors.forename: Kenneth T
authors.initials: KT
authors.lastname: Macleod
authors.affiliation: Myocardial Function, National Heart and Lung Institute, Imperial College London, London, UK. Electronic address: e.dupont@imperial.ac.uk.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Dupont
mesh_terms: D000818:Animals; D002460:Cell Line; D018031:Connexin 43 / Q000235:genetics* / Q000378:metabolism; D017630:Connexins / Q000235:genetics* / Q000378:metabolism; D004594:Electrophysiology / Q000379:methods; D004847:Epithelial Cells / Q000502:physiology; D005786:Gene Expression Regulation; D008099:Liver / Q000166:cytology; D051381:Rats; D000097003:Gap Junction alpha-5 Protein
chemical_list: D018031:Connexin 43; D017630:Connexins; D000097003:Gap Junction alpha-5 Protein; C580592:Gja1 protein, rat; C082920:connexin 45
keywords: Connexin; Gap junction; Heart; Inducible expression; Rat liver epithelial cells