Regulation of Calcium Release by Calmodulin in Muscle

描述（由申请人提供）：骨骼肌肌浆网（SR）钙（Ca2+）释放通过ryanodine受体（RYR） Ca2+释放通道的改变已经在许多肌肉疾病中被发现，包括恶性高热和中央核心疾病。内源性配体对SR Ca2+释放的调节在这些病变肌肉中也发生了改变。这表明了解内源性调节剂对RYR活性的调节的重要性。利用激光扫描共聚焦显微镜和Ca2+指示剂Fluo-3的技术已经允许在功能完整的骨骼肌中对离散的局部Ca2+释放事件（Ca2+火花）进行成像。检查这些事件在电压或配体刺激下的性质和发生频率，可以深入了解在功能肌纤维的背景下SR Ca2+释放的分子控制。

DESCRIPTION (provided by applicant): Alterations in skeletal muscle sarcoplasmic reticulum (SR) calcium (Ca2+) release via the ryanodine receptor (RYR) Ca2+ release channel have been identified in a number of muscle diseases including malignant hyperthermia and central core disease. The regulation of SR Ca2+ release by endogenous ligands is also altered in these diseased muscles. This signifies the importance of understanding the regulation of RYR activity by endogenous modulators. Techniques utilizing laser scanning confocal microscopy and the Ca2+ indicator Fluo-3 have allowed the imaging of discrete localized Ca2+ release events (Ca2+ sparks) in functionally intact skeletal muscle. Examination of properties and frequency of occurrence of these events in response to either voltage or ligand stimulation is providing insight into the molecular control of SR Ca2+ release within the context of the functioning muscle fiber. The main objective of this proposal is to examine the modulation of the local control of SR Ca2+ release by calmodulin in functionally intact skeletal muscle fibers. Specifically, I intend to examine the effects of calmodulin on spontaneous and voltage activated skeletal muscle Ca2+ spark properties to gain insight into the role calmodulin plays in skeletal muscle excitation contraction coupling. The use of recombinant calmodulin, both wild type and a mutant that cannot bind Ca2+, will allow for the assessment of the role calmodulin plays in the activation, propagation and termination of these discrete localized Ca2+ release events.