National Institutes of Health/National Heart, Lung, and Blood Institute (NIH/NHLBI)
HL007081
米国
National Institutes of Health/National Heart, Lung, and Blood Institute (NIH/NHLBI)
HL007227
米国
National Institutes of Health/National Heart, Lung, and Blood Institute (NIH/NHLBI)
GM138448
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
GM138854
米国
National Institutes of Health/National Heart, Lung, and Blood Institute (NIH/NHLBI)
HL141086
米国
National Institutes of Health/National Heart, Lung, and Blood Institute (NIH/NHLBI)
HL141086
米国
National Institutes of Health/National Heart, Lung, and Blood Institute (NIH/NHLBI)
HL138466
米国
National Institutes of Health/National Heart, Lung, and Blood Institute (NIH/NHLBI)
HL139714
米国
National Institutes of Health/National Heart, Lung, and Blood Institute (NIH/NHLBI)
HL151078
米国
National Institutes of Health/National Heart, Lung, and Blood Institute (NIH/NHLBI)
HL161185
米国
Leducq Foundation
20CVD02
フランス
Burroughs Wellcome Fund
1014782
米国
Childrens Discovery Institute of Washington University and St. Louis Childrens Hospital
CH-II-2015-462
米国
Childrens Discovery Institute of Washington University and St. Louis Childrens Hospital
CH-II-2017-628
米国
Childrens Discovery Institute of Washington University and St. Louis Childrens Hospital
PM-LI-2019-829
米国
引用
ジャーナル: Proc Natl Acad Sci U S A / 年: 2024 タイトル: Dilated cardiomyopathy-associated skeletal muscle actin (ACTA1) mutation R256H disrupts actin structure and function and causes cardiomyocyte hypocontractility. 著者: Ankit Garg / Silvia Jansen / Lina Greenberg / Rui Zhang / Kory J Lavine / Michael J Greenberg / 要旨: Skeletal muscle actin (ACTA1) mutations are a prevalent cause of skeletal myopathies consistent with ACTA1's high expression in skeletal muscle. Rare de novo mutations in ACTA1 associated with ...Skeletal muscle actin (ACTA1) mutations are a prevalent cause of skeletal myopathies consistent with ACTA1's high expression in skeletal muscle. Rare de novo mutations in ACTA1 associated with combined cardiac and skeletal myopathies have been reported, but ACTA1 represents only ~20% of the total actin pool in cardiomyocytes, making its role in cardiomyopathy controversial. Here we demonstrate how a mutation in an actin isoform expressed at low levels in cardiomyocytes can cause cardiomyopathy by focusing on a unique ACTA1 variant, R256H. We previously identified this variant in a family with dilated cardiomyopathy, who had reduced systolic function without clinical skeletal myopathy. Using a battery of multiscale biophysical tools, we show that R256H has potent effects on ACTA1 function at the molecular scale and in human cardiomyocytes. Importantly, we demonstrate that R256H acts in a dominant manner, where the incorporation of small amounts of mutant protein into thin filaments is sufficient to disrupt molecular contractility, and that this effect is dependent on the presence of troponin and tropomyosin. To understand the structural basis of this change in regulation, we resolved a structure of R256H filaments using cryoelectron microscopy, and we see alterations in actin's structure that have the potential to disrupt interactions with tropomyosin. Finally, we show that human-induced pluripotent stem cell cardiomyocytes demonstrate reduced contractility and sarcomeric organization. Taken together, we demonstrate that R256H has multiple effects on ACTA1 function that are sufficient to cause reduced contractility and establish a likely causative relationship between ACTA1 R256H and clinical cardiomyopathy.
ソフトウェア - 名称: cryoSPARC (ver. 3.4) 詳細: Actin filaments were automatically picked from the micrographs using template based 'Filament tracer' in CryoSPARC
初期モデル
モデルのタイプ: OTHER / 詳細: 'Ab-Initio Reconstruction' in CryoSPARC
最終 角度割当
タイプ: NOT APPLICABLE / ソフトウェア - 名称: cryoSPARC (ver. 3.4)