title: Molecular mechanism regulating myosin and cardiac functions by ELC.
abstract: The essential myosin light chain (ELC) is involved in modulation of force generation of myosin motors and cardiac contraction, while its mechanism of action remains elusive. We hypothesized that ELC could modulate myosin stiffness which subsequently determines its force production and cardiac contraction. Therefore, we generated heterologous transgenic mouse (TgM) strains with cardiomyocyte-specific expression of ELC with human ventricular ELC (hVLC-1; TgM(hVLC-1)) or E56G-mutated hVLC-1 (hVLC-1(E56G); TgM(E56G)). hVLC-1 or hVLC-1(E56G) expression in TgM was around 39% and 41%, respectively of total VLC-1. Laser trap and in vitro motility assays showed that stiffness and actin sliding velocity of myosin with hVLC-1 prepared from TgM(hVLC-1) (1.67 pN/nm and 2.3 μm/s, respectively) were significantly higher than myosin with hVLC-1(E56G) prepared from TgM(E56G) (1.25 pN/nm and 1.7 μm/s, respectively) or myosin with mouse VLC-1 (mVLC-1) prepared from C57/BL6 (1.41 pN/nm and 1.5 μm/s, respectively). Maximal left ventricular pressure development of isolated perfused hearts in vitro prepared from TgM(hVLC-1) (80.0 mmHg) were significantly higher than hearts from TgM(E56G) (66.2 mmHg) or C57/BL6 (59.3±3.9 mmHg). These findings show that ELCs decreased myosin stiffness, in vitro motility, and thereby cardiac functions in the order hVLC-1>hVLC-1(E56G)≈mVLC-1. They also suggest a molecular pathomechanism of hypertrophic cardiomyopathy caused by hVLC-1 mutations.
authors.affiliation: University Medicine Berlin Charité, Experimental and Clinical Research Center (ECRC), Germany.
authors.forename: Janine
authors.initials: J
authors.lastname: Lossie
authors.affiliation: University Medicine Berlin Charité, Experimental and Clinical Research Center (ECRC), Germany.
authors.forename: Clemens
authors.initials: C
authors.lastname: Köhncke
authors.affiliation: University Medicine Berlin Charité, Institute of Gender in Medicine, Germany; Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany.
authors.forename: Shokoufeh
authors.initials: S
authors.lastname: Mahmoodzadeh
authors.affiliation: Medizinische Hochschule Hannover, Institut fuer Molekular- und Zellphysiologie, Germany.
authors.forename: Walter
authors.initials: W
authors.lastname: Steffen
authors.affiliation: Department of Molecular Medicine and Sport Medicine Research Center, University of Pavia, Italy.
authors.forename: Monica
authors.initials: M
authors.lastname: Canepari
authors.affiliation: Department of Molecular Medicine and Sport Medicine Research Center, University of Pavia, Italy.
authors.forename: Manuela
authors.initials: M
authors.lastname: Maffei
authors.affiliation: Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Taube
authors.affiliation: Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany.
authors.forename: Oriane
authors.initials: O
authors.lastname: Larchevêque
authors.affiliation: Johann Wolfgang Goethe-Universitaet, Institut für Sportwissenschaften, Frankfurt/Main, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Baumert
authors.affiliation: Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany.
authors.forename: Hannelore
authors.initials: H
authors.lastname: Haase
authors.affiliation: Department of Molecular Medicine and Sport Medicine Research Center, University of Pavia, Italy; Fondazione Salvatore Maugeri, Scientific Institute of Pavia, Pavia, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Bottinelli
authors.affiliation: University Medicine Berlin Charité, Institute of Gender in Medicine, Germany.
authors.forename: Vera
authors.initials: V
authors.lastname: Regitz-Zagrosek
authors.affiliation: Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany; University Medicine Berlin Charité, Germany. Electronic address: imorano@mdc-berlin.de.
authors.forename: Ingo
authors.initials: I
authors.lastname: Morano
mesh_terms: D000818:Animals; D055119:Elastic Modulus; D006321:Heart / Q000502:physiology*; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D020409:Molecular Motor Proteins / Q000737:chemistry / Q000502:physiology / Q000648:ultrastructure; D009200:Myocardial Contraction / Q000502:physiology*; D018994:Myosin Light Chains / Q000737:chemistry* / Q000378:metabolism* / Q000648:ultrastructure; D013329:Structure-Activity Relationship; D013718:Tensile Strength / Q000502:physiology
chemical_list: D020409:Molecular Motor Proteins; D018994:Myosin Light Chains
keywords: Essential myosin light chains; In vitro motility; Mutations; Myosin; Stiffness