STRUCTURAL AND FUNCTIONAL INTERACTIONS BETWEEN THE II-III LOOP OF THE SKELETAL DHPR AND THE RYANODINE RECEPTOR

该项目对神经肌肉疾病、一般肌肉无力和老年人都有影响，所有这些都是重大的健康问题。这一结果将阐明肌肉收缩的分子机制，并将为肌肉疾病的药物设计和治疗提供依据。呼吸和运动依赖于肌肉细胞内钙浓度的变化。心血管功能、神经活动和免疫反应也依赖于体内钙的释放。Ryanodine受体(RyR)钙通道单独或与不同的内部钙通道结合，在这些不同的功能中调节钙的释放。当RyR表达有缺陷时，出生时或出生前死亡就突显了RyR的本质。RyR基因缺陷会导致心律失常、恶性体温过高和中枢性核心病。RyR功能因心力衰竭和疲劳而受损。RyRs的关键作用使其成为潜在的治疗靶点，但由于对其调控部位的性质和结构的有限了解，它们并未被用作治疗靶点。来自大脑的电信号能够从肌肉内部储存的钙释放出来，并通过两个钙通道蛋白之间的物理相互作用启动肌肉收缩，这两个钙通道蛋白是表面膜通道和RyR。这种蛋白质-蛋白质相互作用的分子基础还不清楚，是这项提议的主题。我们将(A)解决已知有助于蛋白质与RyR相互作用的表面通道的一部分的结构，(B)确定相互作用的氨基酸残基，以及(C)评估蛋白质结合的功能后果。更多地了解RyR的调控将为合理的药物设计和最终将RyR用作治疗靶点铺平道路。

The project has implications for neuromuscular diseases and for muscle weakness in general and in the elderly, all of which are significant health issues. The results will elucidate molecular mechanisms in muscle contraction and will provide a basis for drug design and treatment of muscle disorders. Respiration and locomotion depend on changes in calcium concentration inside muscle cells. Cardiovascular function, neuronal activity and immune responses also depend on the release of calcium from internal stores. Ryanodine receptor (RyR) calcium channels, either alone or in combination with a different internal calcium channel, regulate calcium release in each of these diverse functions. The essential nature of RyRs is underlined by death at or before birth when RyR expression is defective. Genetic defects in the RyR cause cardiac arrhythmias, malignant hyperthermia and central core disease. RyR function is compromised in heart failure and fatigue. The key role of RyRs makes them a potential therapeutic target, but they are not used as such because of the limited knowledge of the nature and structure of their regulatory sites. Electrical signals from the brain are able to release calcium from internal stores in muscle and initiate muscle contraction by virtue of a physical interaction between two calcium channel proteins, a surface membrane channel and the RyR. The molecular basis of this protein-protein interaction is is not understood and is a subject of this proposal. We will (a) solve the structure of one part of the surface channel that is known to contribute to the protein-protein interaction with the RyR, (b) determine the amino acid residues that interact with each other and (c) evaluate the functional consequences of the the binding of proteins. Understanding more about RyR regulation will pave the way for rational drug design and the eventual use of the RyR as a therapeutic target.