Functional Characterization of Cardiac Actin Mutants Causing Hypertrophic (p.A295S) and Dilated Cardiomyopathy (p.R312H and p.E361G).

Autor: Hassoun R; Institut für Forschung und Lehre (IFL), Molecular and Experimental Cardiology, Medical Faculty, Ruhr University Bochum, D-44791 Bochum, Germany.; Department of Cardiology, St. Josef-Hospital, Medical Faculty, Ruhr University Bochum, D-44791 Bochum, Germany., Erdmann C; Department of Anatomy and Molecular Embryology, Medical Faculty, Ruhr-University Bochum, D-44780 Bochum, Germany., Schmitt S; Institute of Structural Biology, University of Bonn, D-53127 Bonn, Germany., Fujita-Becker S; Cryoelectron Microscopy, BioQuant, Medical Faculty, University of Heidelberg, D-69120 Heidelberg, Germany., Mügge A; Institut für Forschung und Lehre (IFL), Molecular and Experimental Cardiology, Medical Faculty, Ruhr University Bochum, D-44791 Bochum, Germany.; Department of Cardiology, St. Josef-Hospital, Medical Faculty, Ruhr University Bochum, D-44791 Bochum, Germany., Schröder RR; Cryoelectron Microscopy, BioQuant, Medical Faculty, University of Heidelberg, D-69120 Heidelberg, Germany., Geyer M; Institute of Structural Biology, University of Bonn, D-53127 Bonn, Germany., Borbor M; Department of Neurology, University Hospital Essen, D-45147 Essen, Germany., Jaquet K; Institut für Forschung und Lehre (IFL), Molecular and Experimental Cardiology, Medical Faculty, Ruhr University Bochum, D-44791 Bochum, Germany.; Department of Cardiology, St. Josef-Hospital, Medical Faculty, Ruhr University Bochum, D-44791 Bochum, Germany., Hamdani N; Institut für Forschung und Lehre (IFL), Molecular and Experimental Cardiology, Medical Faculty, Ruhr University Bochum, D-44791 Bochum, Germany.; Department of Cardiology, St. Josef-Hospital, Medical Faculty, Ruhr University Bochum, D-44791 Bochum, Germany., Mannherz HG; Institut für Forschung und Lehre (IFL), Molecular and Experimental Cardiology, Medical Faculty, Ruhr University Bochum, D-44791 Bochum, Germany.; Department of Anatomy and Molecular Embryology, Medical Faculty, Ruhr-University Bochum, D-44780 Bochum, Germany.
Jazyk: angličtina
Zdroj: International journal of molecular sciences [Int J Mol Sci] 2022 Apr 18; Vol. 23 (8). Date of Electronic Publication: 2022 Apr 18.
DOI: 10.3390/ijms23084465
Abstrakt: Human wild type (wt) cardiac α-actin and its mutants p.A295S or p.R312H and p.E361G correlated with hypertrophic or dilated cardiomyopathy, respectively, were expressed by using the baculovirus/Sf21 insect cell system. The c-actin variants inhibited DNase I, indicating maintenance of their native state. Electron microscopy showed the formation of normal appearing actin filaments though they showed mutant specific differences in length and straightness correlating with their polymerization rates. TRITC-phalloidin staining showed that p.A295S and p.R312H exhibited reduced and the p.E361G mutant increased lengths of their formed filaments. Decoration of c-actins with cardiac tropomyosin (cTm) and troponin (cTn) conveyed Ca 2+ -sensitivity of the myosin-S1 ATPase stimulation, which was higher for the HCM p.A295S mutant and lower for the DCM p.R312H and p.E361G mutants than for wt c-actin. The lower Ca 2+ -sensitivity of myosin-S1 stimulation by both DCM actin mutants was corrected by the addition of levosimendan. Ca 2+ -dependency of the movement of pyrene-labeled cTm along polymerized c-actin variants decorated with cTn corresponded to the relations observed for the myosin-S1 ATPase stimulation though shifted to lower Ca 2+ -concentrations. The N-terminal C0C2 domain of cardiac myosin-binding protein-C increased the Ca 2+ -sensitivity of the pyrene-cTM movement of bovine, recombinant wt, p.A295S, and p.E361G c-actins, but not of the p.R312H mutant, suggesting decreased affinity to cTm.
Databáze: MEDLINE
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