Molecular basis for gating and regulation of cardiac ryanodine receptor: underlying mechanisms for gain- and loss-of function mutations
Molecular basis for gating and regulation of cardiac ryanodine receptor: underlying mechanisms for gain- and loss-of function mutations
复制标题
心脏兰尼碱受体门控和调节的分子基础：功能获得和丧失突变的潜在机制
DOI：
10.1101/2020.11.30.401026
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Ogawa Haruo
中科院分区：
文献类型：
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作者：
Kobayashi Takuya;Tsutsumi Akihisa;Kurebayashi Nagomi;Saito Kei;Kodama Masami;Sakurai Takashi;Kikkawa Masahide;Murayama Takashi;Ogawa Haruo
心脏ryanodine受体（RyR 2）是肌浆网中的大的Ca 2+释放通道，并且在心脏中的兴奋-收缩偶联中是不可缺少的。RyR 2被Ca 2+激活，RyR 2突变与严重的致瘤性疾病有关。然而，通道开放的结构基础以及突变如何影响通道仍然未知。在这里，我们解决了门控机制的RyR 2通过结合高分辨率的结构确定的冷冻电子显微镜与定量功能分析的通道携带各种突变的特定残基。我们证明了通道门控的两个基本机制：靠近通道孔的相互作用稳定通道以防止过度活跃，以及周围区域的一系列相互作用对于Ca 2+结合后的通道开放是必要的。在前一种和后一种机制中涉及的残基处的突变分别引起功能获得和功能丧失。我们的研究结果揭示了RyR 2通道的门控机制和原子水平上致病突变的改变。
Cardiac ryanodine receptor (RyR2) is a large Ca2+release channel in the sarcoplasmic reticulum and indispensable for excitation-contraction coupling in the heart. RyR2 is activated by Ca2+and RyR2 mutations are implicated in severe arrhythmogenic diseases. Yet, the structural basis underlying channel opening and how mutations affect the channel remain unknown. Here, we addressed gating mechanism of RyR2 by combining high-resolution structures determined by cryo-electron microscopy with quantitative functional analysis of channels carrying various mutations in specific residues. We demonstrated two fundamental mechanisms for channel gating: interactions close to the channel pore stabilize the channel to prevent hyperactivity and a series of interactions in the surrounding regions is necessary for channel opening upon Ca2+binding. Mutations at the residues involved in the former and the latter mechanisms cause gain-of-function and loss-of-function, respectively. Our results reveal gating mechanisms of the RyR2 channel and alterations by pathogenic mutations at the atomic level.