Divergent Activity Profiles of Type 1 Ryanodine Receptor Channels Carrying Malignant Hyperthermia and Central Core Disease Mutations in the Amino-Terminal Region.
Divergent Activity Profiles of Type 1 Ryanodine Receptor Channels Carrying Malignant Hyperthermia and Central Core Disease Mutations in the Amino-Terminal Region.
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DOI：
10.1371/journal.pone.0130606
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Sakurai T
中科院分区：
文献类型：
--
作者：
Murayama T;Kurebayashi N;Yamazawa T;Oyamada H;Suzuki J;Kanemaru K;Oguchi K;Iino M;Sakurai T
1型兰尼碱受体（RyR 1）是骨骼肌肌浆网中的Ca 2+释放通道，并且在几种疾病中突变，包括恶性高热（MH）和中央核心疾病（CCD）。大多数MH和CCD突变会导致Ca 2+释放加速，导致骨骼肌中Ca 2+稳态异常。然而，具体的突变如何影响通道产生不同的表型还不清楚。在这项研究中，我们已经调查了11个在7个不同的位置在氨基（N）-末端区域的RyR 1（9个MH和2个MH/CCD突变）使用异源表达系统在HEK 293细胞。在室温（~25 °C）下的活细胞Ca 2+成像中，表达突变通道的细胞表现出Ca 2+稳态的改变，即，对咖啡因的敏感性增强，ER中Ca 2+的消耗和静息细胞质Ca 2+的增加。RyR 1通道活性通过[3 H]ryanodine结合和三个参数（对激活Ca 2+的敏感性、对失活Ca 2+的敏感性和可达到的最大活性，即，增益）。这些突变以位点特异性方式增加了增益和对激活Ca 2+的敏感性。在MH和MH/CCD突变中，增益始终较高。MH/CCD突变对激活Ca ~（2+）的敏感性显著增强。从这三个参数估计的通道活性提供了一个合理的解释的病理表型评估的Ca 2+稳态。在更高的温度（~37 °C）下也观察到这些性质。我们的数据表明，不同的活性谱可能会导致不同的疾病表型的特定突变。这种方法对于诊断和治疗RyR 1突变的疾病是有用的。
The type 1 ryanodine receptor (RyR1) is a Ca2+ release channel in the sarcoplasmic reticulum of skeletal muscle and is mutated in several diseases, including malignant hyperthermia (MH) and central core disease (CCD). Most MH and CCD mutations cause accelerated Ca2+ release, resulting in abnormal Ca2+ homeostasis in skeletal muscle. However, how specific mutations affect the channel to produce different phenotypes is not well understood. In this study, we have investigated 11 mutations at 7 different positions in the amino (N)-terminal region of RyR1 (9 MH and 2 MH/CCD mutations) using a heterologous expression system in HEK293 cells. In live-cell Ca2+ imaging at room temperature (~25 °C), cells expressing mutant channels exhibited alterations in Ca2+ homeostasis, i.e., an enhanced sensitivity to caffeine, a depletion of Ca2+ in the ER and an increase in resting cytoplasmic Ca2+. RyR1 channel activity was quantitatively evaluated by [3H]ryanodine binding and three parameters (sensitivity to activating Ca2+, sensitivity to inactivating Ca2+ and attainable maximum activity, i.e., gain) were obtained by fitting analysis. The mutations increased the gain and the sensitivity to activating Ca2+ in a site-specific manner. The gain was consistently higher in both MH and MH/CCD mutations. Sensitivity to activating Ca2+ was markedly enhanced in MH/CCD mutations. The channel activity estimated from the three parameters provides a reasonable explanation to the pathological phenotype assessed by Ca2+ homeostasis. These properties were also observed at higher temperatures (~37 °C). Our data suggest that divergent activity profiles may cause varied disease phenotypes by specific mutations. This approach should be useful for diagnosis and treatment of diseases with mutations in RyR1.
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影响因子：
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通讯作者：
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