RELEASE CHANNEL ISOFORMS AND LOCAL CALCIUM SIGNALING

描述：（申请人摘要） Ryanodine受体（Ryr，Ca 2+释放通道）在细胞内的钙通道中起着重要作用。 肌肉收缩。它主要位于肌浆网 (SR)与T管和表面膜形成连接（T-SR连接）。它 负责从SR释放Ca 2+，触发收缩。释放 通道被认为是由两种不同的机制激活：机械 与二氢吡啶受体（DHPr，电压传感器）相互作用， 钙诱导的钙释放（CICR）。 骨骼肌含有不同的Ryr亚型，可能有助于 兴奋-收缩偶联（ECC）机制的多样性。我的初步 数据揭示了两种不同类型的局部Ca 2+信号传导：Ca 2+火花和 在小事件中释放。本提案的目的是调查 不同释放通道亚型在Ca ~（2+）释放中的作用。我建议采取 两种主要骨骼肌Ryr的相对量 亚型（Ryr 1和Ryr 3）在肌肉类型之间和肌肉过程中差异很大 为了测试三个主要假设： 1.小事件中的Ca 2+释放直接受电压控制， 激活钙火花的前体钙离子。 2. Ca 2+火花是通过打开多个Ryr Ca 2+释放通道产生的。 3. Ryr 3rs是在骨骼肌中产生火花所需的通道， 由CICR激活。 为此，我们将探讨各种成熟和成熟的细胞中的局部钙信号传导， 发育中的哺乳动物、两栖动物和鱼类骨骼肌纤维， Ryr同种型组成和/或每个T-SR连接处的Ryr数量不同。在 同时，我们将通过以下方法监测不同Ryr亚型的组织表达： 免疫印迹和/或免疫染色。 一些肌肉疾病越来越多地被理解为肌肉缺陷。 参与ECC的分子。拟议的研究将大大促进我们的 了解它们的功能，这反过来可以提高我们对它们的理解。 他们在死亡中的角色。

DESCRIPTION: (Applicant's Abstract) The ryanodine receptor (Ryr, Ca2+ release channel) plays a central role in muscle contraction. It is mainly localized where the sarcoplasmic reticulum (SR) forms junctions with T-tubular and surface membranes (T-SR junction). It is responsible for release of Ca2+ from SR that triggers contraction. Release channels are suggested to be activated by two different mechanisms: mechanical interaction with dihydropyridine receptor (DHPr, voltage sensor) and calcium-induced calcium release (CICR). Skeletal muscle contains different Ryr isoforms that might contribute to the diversity of excitation-contraction coupling (ECC) mechanisms. My preliminary data disclosed two distinctive types of local Ca2+ signaling: Ca2+ sparks and release in small events. The goal of this proposal is to investigate the role of different release channel isoforms in Ca2+ release. I propose to take advantage of the fact that relative amounts of two major skeletal muscle Ryr isoforms (Ryrl and Ryr3) vary widely between muscle types and during muscle development in order to test three major hypotheses: 1. Ca2+ release in small events is directly controlled by voltage and provides a precursor Ca2+ that activates Ca2+ sparks. 2. Ca2+ sparks are produced by opening of multiple Ryr Ca2+ release channels. 3. Ryr3rs are the channels required to produce sparks in skeletal muscle and are activated by CICR. For this we will explore local calcium signaling in a variety of mature and developing mammalian, amphibian and fish skeletal muscle fibers with different Ryr isoforms composition and/or different numbers of Ryrs per T-SR junction. In parallel, we will monitor tissue expression of different Ryr isoforms by immunoblotting and/or immunostaining. Some muscle illnesses are increasingly been understood in terms of defects of molecules participating in ECC. Proposed studies will greatly advanced our knowledge of their functioning, which in turn could improve our understanding of their role in decease.