RELEASE CHANNEL ISOFORMS AND LOCAL CALCIUM SIGNALING

描述：(申请人摘要) Ryanodine受体(RyR，钙释放通道)在 肌肉收缩。它主要定位于肌浆网 (Sr)与T型管和表面膜形成连接(T-SR连接)。它 负责从SR释放钙离子，从而触发收缩。发布 建议通过两种不同的机制来激活通道：机械 与二氢吡啶受体(DHPr，电压传感器)和 钙诱导钙释放(CICR)。 骨骼肌含有不同的RyR亚型，可能有助于 兴奋收缩耦合(ECC)机制的多样性。我的初选 数据揭示了两种不同类型的局部钙信号：钙火花和 在小型活动中发布。这项提案的目标是调查 不同释放通道亚型在钙离子释放中的差异。我建议采取 两个主要骨骼肌RyR的相对量的优势 亚型(Ryr1和Ryr3)在不同的肌肉类型和不同的肌肉过程中差异很大 开发以检验三个主要假设： 1.小事件中的Ca~(2+)释放直接受电压控制，并提供 一种激活钙离子的前体钙离子会产生火花。 2.钙火花是通过开放多种RyR钙离子释放通道而产生的。 3.Ryr3r是在骨骼肌中产生火花所需的通道， 是由CICR激活的。 为此，我们将探索在各种成熟和 哺乳动物、两栖动物和鱼类骨骼肌纤维的发育 每个T-SR连接的RyR亚型组成和/或不同数量的RyR。在……里面 同时，我们将通过以下方式监测不同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 参与ECC的分子。拟议的研究将极大地促进我们的 对它们功能的了解，这反过来可以提高我们的理解 他们在死亡中所扮演的角色。

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.