Sub-Project #3

骨骼肌Ca 2+释放通道，也称为兰尼碱受体（RYR 1），调节 从肌浆网（SR）释放的Ca 2+在人中央核心储存并突变 疾病（CCD）和药物遗传学综合征，恶性高热（MH）。的 RYR 1的突变集中在三个区域：第1区从氨基酸35至614，第2区从氨基酸35至614， 2163至2459和区域3从4647至4914。MH突变主要位于细胞质中， 在跨膜区1和跨膜区2中发现大部分CCD突变，而在跨膜区3中发现大部分CCD突变。的 本项目中有待检验的工作假设是：a.区域1和2，位于夹具中 结构域相互作用以变构稳定通道的闭合状态，B. MH突变，通过 使这种相互作用不稳定，增强通道（因此肌肉）对激活剂的反应 和升高的温度，C.运动过程中RyR 1活性的增强提高了内源性 作为热原的细胞因子（如IL-6）和随后的体温升高 增加了MH响应的可能性。为了验证这些假设，以下具体目标 建议：A1。定义MH/CCD突变对以下构象变化的影响： RyR 1 A2的钳位结构域。评估MH/CCD突变对结构和功能的影响。 肌肉的收缩特性。A3.确定运动诱发MH的概率 升高的体温和/或升高的体温增加了横纹肌溶解和/或横纹肌溶解增加了 内源性IL-6浓度。这些研究将使用具有MH/CCD突变的小鼠， 在项目1和3中生成。

The skeletal muscle Ca2+ release channel, also known as the ryanodine receptor (RYR1), regulates the release of Ca2+ from sarcoplasmic reticulum (SR) stores and is mutated in human central core disease (CCD) and in the pharmacogenetic syndrome, malignant hyperthermia (MH). The mutations cluster in three regions of RYR1: region 1 from amino acids 35 to 614, region 2 from 2163 to 2459 and region 3 from 4647-4914. The MH mutations are located primarily in cytoplasmic regionsl and 2 while most of the CCD mutations are found in the transmembrane region 3. The working hypotheses to be tested in this project are: a. Regions 1 and 2, located in the clamp domain, interact to allosterically stabilize a closed state of the channel, b. The MH mutations, by destabilizing this interaction, enhance the response of the channel (and hence muscle) to activators and elevated temperature, c. Enhanced RyR1 activity during exercise elevates endogenous cytokines that act as pyrogens (such as IL-6) and the subsequent increase in body temperature increases the probability of an MH response. To test these hypotheses, the following specific aims are proposed: A1. Define the effects of the MH/CCD mutations on the conformational changes in the clamp domain of RyR1 A2. Evaluate the effects of the MH/CCD mutations on the structural and contractile properties of the muscle. A3. Determine if the probability of exercise-induced MH responses and/or rhabdomyolysis is increased by elevated body temperature and/or increased endogenous IL-6 concentrations. These studies will use mice with MH/CCD mutations that have been generated in Projects 1 and 3.