3-NITROTYROSINE IN AGING OF SKELETAL MUSCLE AND HEART

描述：（改编自应用程序）。 长期目标是 项目是为了了解细胞内钙离子的起源， 伴随骨骼肌和心肌老化的瞬态。 这些 研究者将集中研究肌浆网（SR）Ca-ATPase， 介导钙的限速再隔离， 细胞溶质钙的静息水平用于肌肉松弛。 因此，赤字 在活性钙转运的Ca-ATP酶可能负责 观察到老年心肌和骨骼肌的松弛时间延长。 根据他们最近的观察，假设 3-CaATP酶的SERCA 2a同种型的硝基酪氨酸（3 NY）修饰 在老年骨骼肌中的积累解释了这些缺陷， 收缩性老年心脏SERCA 2a基因3 NY修饰的出现 表明对心肌也有影响 3 NY修改是一个 过氧亚硝酸盐（ONOO-）的特征指示剂，其在体内由以下物质形成： 超氧化物和一氧化氮的扩散限制反应， 大量的肌肉。 3 NY的形成和伴随的失活 Ca-ATP酶可以通过将分离的SR膜体外暴露于 ONOO-. 3 NY形成对SERCA 2a同种型的选择性 钙ATP酶，无论是在体外和在老年骨骼肌，以排除的 高度同源SERCA 1亚型，涉及受磷蛋白， 选择性表达SERCA 2a，作为氧化应激的关键因子 骨骼肌和心肌 因此，具体目标包括：（1） 确定受磷蛋白在SERCA 2a选择性硝化中的作用 （2）比较了SERCA 2a在不同浓度的Ca-ATPase中的氧化修饰情况， 衰老过程中心脏和骨骼肌的变化;（3）鉴定衰老过程中心脏和骨骼肌的变化。 每个体内和体外3 NY位点的功能相关性及其 构象的后果;和（4）描述的构象特征 硝化的SERCA 2a，其产生用于酶活性的底物。 描述导致缺陷的氧化应激途径 钙调节与人类健康有关，因为这种理解是一种 设计有效疗法的先决条件， 衰老过程中的肌肉功能和防止心肌梗死的恶化 手术和其他涉及氧化应激的治疗过程中的损伤。

DESCRIPTION: (Adapted from the Application). The long-term goal of this project is to understand the origin of the prolonged intracellular calcium transients that accompany aging of skeletal and cardiac muscle. These investigators will focus on the sarcoplasmic reticulum (SR) Ca-ATPase which mediates the rate limiting re sequestration of calcium that reestablishes resting levels of cytosolic calcium for muscle relaxation. Therefore deficits in active calcium transport by the Ca-ATPase are likely responsible for the prolonged relaxation times observed for aged cardiac and skeletal muscle. Based on their recent observations, it is hypothesized that the multiple 3-nitrotyrosine (3NY) modifications of the SERCA2a isoform of the CaATPase that accumulate in aged skeletal muscle explain these defects in contractility. The appearance of 3NY modification of SERCA2a in the aged heart suggests effects on cardiac muscle as well. 3NY modification is a characteristic indicator of peroxynitrite (ONOO-) which is formed in vivo by the diffusion-limited reaction of superoxide and nitric oxide, both produced in abundance in muscle. 3NY formation and concomitant inactivation of the Ca-ATPase can be simulated by in vitro exposure of isolated SR membranes to ONOO-. The selectivity of 3NY formation to the SERCA2a isoform of the Ca-ATPase, both in vitro and in aged skeletal muscle, to the exclusion of the highly homologous SERCA1 isoform, implicate phospholamban, which is selectively expressed with SERCA2a, as a critical factor in oxidative stress to skeletal and cardiac muscle. Therefore, the specific aims include: (1) Identify the role of phospholamban in the selective nitration of the SERCA2a isofomm of the Ca-ATPase; (2) Compare the oxidative modification of SERCA2a in the heart with that in skeletal muscle during aging; (3) Identify the functional relevance of each in vivo and in vitro 3NY site and its conformational consequences; and (4) describe the conformational features of nitrated SERCA2a that create a substrate for the denitrase activity. Delineation of pathways resulting from oxidative stress that lead to defects in calcium regulation is relevant to human health as this understanding is a prerequisite for design of effective therapies for both mitigating bass of muscle function during aging and preventing the exacerbation of myocardial damage during surgery and other therapies involving oxidative stress.