RyR2 C-terminal truncating variants identified in patients with arrhythmic phenotypes exert a dominant negative effect through formation of wildtype-truncation heteromers.

Autor:	Tian S; Libin Cardiovascular Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta T2N 4N1, Canada., Zhong X; Libin Cardiovascular Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta T2N 4N1, Canada., Wang H; Libin Cardiovascular Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta T2N 4N1, Canada., Wei J; Libin Cardiovascular Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta T2N 4N1, Canada.; School of Medicine, Northwest University, Xi'an 710069, China., Guo W; Libin Cardiovascular Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta T2N 4N1, Canada., Wang R; Libin Cardiovascular Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta T2N 4N1, Canada., Paul Estillore J; Libin Cardiovascular Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta T2N 4N1, Canada., Napolitano C; European Reference Network 'ERN GUARD-Heart', Amsterdam, Netherlands.; Division of Cardiology and Molecular Cardiology, IRCCS Maugeri Foundation-University of Pavia, 27100 Pavia, Italy.; Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy., Duff HH; Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada., Ilhan E; Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada., Knight LM; Children's Healthcare of Atlanta Cardiology, Atlanta, Georgia, U.S.A., Lloyd MS; Emory University School of Medicine, Atlanta, Georgia, U.S.A., Roberts JD; Population Health Research Institute, McMaster University, and Hamilton Health Sciences, Hamilton, Ontario, Canada., Priori SG; European Reference Network 'ERN GUARD-Heart', Amsterdam, Netherlands.; Division of Cardiology and Molecular Cardiology, IRCCS Maugeri Foundation-University of Pavia, 27100 Pavia, Italy.; Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy.; Molecular Cardiology Laboratory, Centro de Investigaciones Cardiovasculares Carlos III, 28029 Madrid, Spain., Chen SRW; Libin Cardiovascular Institute, Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta T2N 4N1, Canada.
Jazyk:	angličtina
Zdroj:	The Biochemical journal [Biochem J] 2023 Sep 13; Vol. 480 (17), pp. 1379-1395.
DOI:	10.1042/BCJ20230254
Abstrakt:	Gain-of-function missense variants in the cardiac ryanodine receptor (RyR2) are linked to catecholaminergic polymorphic ventricular tachycardia (CPVT), whereas RyR2 loss-of-function missense variants cause Ca2+ release deficiency syndrome (CRDS). Recently, truncating variants in RyR2 have also been associated with ventricular arrhythmias (VAs) and sudden cardiac death. However, there are limited insights into the potential clinical relevance and in vitro functional impact of RyR2 truncating variants. We performed genetic screening of patients presenting with syncope, VAs, or unexplained sudden death and in vitro characterization of the expression and function of RyR2 truncating variants in HEK293 cells. We identified two previously unknown RyR2 truncating variants (Y4591Ter and R4663Ter) and one splice site variant predicted to result in a frameshift and premature termination (N4717 + 15Ter). These 3 new RyR2 truncating variants and a recently reported RyR2 truncating variant, R4790Ter, were generated and functionally characterized in vitro. Immunoprecipitation and immunoblotting analyses showed that all 4 RyR2 truncating variants formed heteromers with the RyR2-wildtype (WT) protein. Each of these C-terminal RyR2 truncations was non-functional and suppressed [3H]ryanodine binding to RyR2-WT and RyR2-WT mediated store overload induced spontaneous Ca2+ release activity in HEK293 cells. The expression of these RyR2 truncating variants in HEK293 cells was markedly reduced compared with that of the full-length RyR2 WT protein. Our data indicate that C-terminal RyR2 truncating variants are non-functional and can exert a dominant negative impact on the function of the RyR2 WT protein through formation of heteromeric WT/truncation complex. (© 2023 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.)
Databáze:	MEDLINE
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