MODULATION OF CALCIUM FLUXES IN HEART AND SMOOTH MUSCLE

我们正在进行的计划的长期目标是理解兴奋- 肌肉(骨骼肌、心脏和平滑肌)的收缩(E-C)耦合。 重点介绍了该系统的结构、功能和调控。 细胞内钙释放通道--一类新的通道 以其庞大的体型和四重对称性为特点。ICRC是 在为细胞动员细胞内存储的钙离子中的重要作用 发信号。有两种类型，兰尼定受体(RyR)和IP3 受体(IP3R)。我们实验室的两个最新发现提供了依据 关于RyR受体调节的关键拟议研究。 1)精子网末端池的磷酸化。 蛋白激酶使通道活动，而磷酸酶起作用 使通道处于非活动状态， 生理[Mg2+]；2)FK结合蛋白(FKBP)，其受体 免疫抑制药物FK5O61与兰尼定受体紧密结合 骨骼肌(RyR-1)和心脏(RyR-2)的亚型。有7个目标： 1)表征RyR-1和RyR-2活性调节的性质 由蛋白激酶和磷酸酶组成 2)研究血管平滑肌对IP3受体的调节作用 蛋白激酶/磷酸酶的磷酸化/去磷酸化。这个 实验方法类似于RyR的方法。(见目标1)。 3)蛋白水解法测定IP3R的表面拓扑结构 敏感度映射。也就是说，完整的受体将被 选择性蛋白水解酶及其形成的多肽的鉴定 化学测序。每个肽都识别一个特定的肽键 受体的表面。 4)继续RyR的三维结构分析研究 心脏和骨骼肌，并启动对IP3 R的研究(一起 与特伦斯·瓦根克内希特博士及同事)。 5)评估患者的生理相关性和功能后果 FKBP与骨骼肌和心脏兰尼定的关系 感受器。 6)定义FKBP和RyR受体上的表面界面 两种骨骼中特异性FKBP亚型与RyR的关系 肌肉(FKBP12/RyR1)和心脏(FKBP-C/RyR2) 7)评估FKBP和磷酸化/去磷酸化在 调节骨骼肌和心肌的E-C偶联。我们的节目是 旨在将ICRC的结构/功能关系与 它们与钙稳态和E-C偶联的生理关系 肌肉。

The long term goal of our ongoing program is to understand excitation- contraction (E-C) coupling in muscle (skeletal, heart and smooth muscle). The emphasis is on the structure, function and regulation of the intracellular calcium release channels (ICRCs), a new class of channels characterized by their large size and four-fold symmetry. ICRCs are important in mobilizing Ca2+ from intracellular stores for cell signalling. There are two types, the ryanodine receptor (RyR) and the IP3 receptor (IP3R). Two recent findings in our laboratory provide the basis of key proposed studies regarding the modulation of the RyR receptor. 1)Phosphorylation of terminal Cisternae of sacroplasmic reticulum by protein kinases renders the channel active, whereas phosphatase action renders the channel inactive, in the presence of approximately physiological [Mg2+].; 2) FK binding protein (FKBP), the receptor for the immunosuppressive drug FK5O61 is tightly bound to the ryanodine receptor isoforms of skeletal muscle (RyR-1) and heart (RyR-2). There are 7 aims: 1) Characterize the nature of the modulation of RyR-1 and RyR-2 activity by protein kinases and phosphatases 2) Study the modulation of the IP3 R from smooth muscle by phosphorylation/dephosphorylation with protei kinases/phosphatases. The experimental approach is similar to that for the RyR. (See Aim 1). 3) Determine surface topology of IP3 R from smooth muscle by proteolysis sensitivity mapping. That is, the intact receptor will be cleaved by selective proteolytic digestion and the peptides formed identified by chemical sequencing. Each peptide identifies a specific peptide bond on the surface of the receptor. 4) Continue three-dimensional structure analysis studies of the RyR from heart and skeletal muscle and initiate studies with the IP3 R (together with Dr. Terrence Wagenknecht and colleagues). 5) Assess the physiological relevance and functional consequence of the association of the FKBP with skeletal muscle and heart ryanodine receptors. 6) Define the surface interfaces on FKBP and on the RyR receptor in the association of specific FKBP isoforms with the RyR for both skeletal muscle (FKBP12/RyR1) and heart (FKBP-C/RyR2) 7) Evaluate the role of FKBP and phosphorylation/dephosphorylation in modulating E-C coupling in skeletal muscle and heart. Our program is designed to correlate structure/function relationships of the ICRCs and their physiological relevance to calcium homeostasis and E-C coupling in muscle.