MODULATION OF CALCIUM FLUXES IN HEART AND SMOOTH MUSCLE

心脏和平滑肌钙通量的调节

• 批准号: 2378718
• 负责人: SIDNEY FLEISCHER
• 金额: $ 26.85万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1984
• 资助国家: 美国
• 起止时间: 1984-12-01 至 1999-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2378718
• 关键词: DVD /CD ROM; binding proteins; calcium channel; calcium flux; drug receptors; electron microscopy; electrophysiology; homeostasis; inositol phosphates; laboratory rabbit; muscle contraction; myocardium; peptidylprolyl isomerase; phosphoprotein phosphatase; phosphorylation; protein isoforms; protein kinase; protein sequence; protein structure function; proteolysis; receptor; smooth muscle; spectrometry

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.

我们正在进行的计划的长期目标是了解激发 - 肌肉（骨骼，心脏和平滑肌）的收缩（E-C）耦合。 重点在于结构，功能和调节 细胞内钙释放通道（ICRCS），一类新的通道 其特征是它们的大尺寸和四倍的对称性。 ICRC是 对于细胞内存储中的Ca2+至关重要 信号。有两种类型：ryanodine受体（RYR）和IP3 受体（IP3R）。我们实验室中的两个最新发现提供了基础 有关RYR受体调节的关键提出的研究。 1）par骨网状末端的磷酸化。 蛋白激酶使通道活跃，而磷酸酶作用 在大约存在的情况下使通道无效 生理[MG2+]。 2）FK结合蛋白（FKBP），该受体的受体 免疫抑制药物FK5O61紧密结合与瑞氨烷受体 骨骼肌（RYR-1）和心脏（RYR-2）的同工型。有7个目标： 1）表征RYR-1和RYR-2活性调制的性质 通过蛋白激酶和磷酸酶 2）研究来自平滑肌的IP3 r的调制 蛋白激酶/磷酸酶的磷酸化/去磷酸化。这 实验方法与RYR相似。 （请参阅目标1）。 3）通过蛋白水解确定来自平滑肌的IP3 R的表面拓扑 灵敏度映射。也就是说，完整的受体将被裂解 选择性蛋白水解消化和由 化学测序。每个肽都鉴定出特定的肽键 受体的表面。 4）继续对RYR的三维结构分析研究 心脏和骨骼肌肉并开始使用IP3 R进行研究（一起 与Terrence Wagenknecht博士及其同事。 5）评估生理相关性和功能后果 FKBP与骨骼肌和心脏ryanodine的关联 受体。 6）定义FKBP和RYR受体上的表面接口 两种骨骼的特定FKBP同工型与RYR的关联 肌肉（FKBP12/RYR1）和心脏（FKBP-C/RYR2） 7）评估FKBP和磷酸化/去磷酸化在 调节骨骼肌和心脏中的E-C耦合。我们的计划是 旨在将ICRC的结构/功能关系相关联 它们与钙稳态和E-C耦合的生理相关性 肌肉。