Regulation and Function of Hsp27 in Zebrafish

小分子热休克蛋白（Small heat shock proteins，sHsps）是一个庞大但知之甚少的蛋白质家族。在脊椎动物和许多无脊椎动物中，sHsps组成性地存在于肌肉细胞中，在那里它们可以在稳态和损伤修复中发挥作用。Shelden实验室获得的初步结果显示，普遍存在的小热休克蛋白Hsp27在肌肉肌原纤维中具有显著的应激依赖性募集。本研究的重点是确定这种募集的机制和功能意义，并具体解决以下问题：1）当Hsp27与肌原纤维结合时，Hsp27是如何调节的，调节对其功能的影响是什么？2)损伤时Hsp27与肌原纤维的结合动力学是什么？（3）Hsp27在肌原纤维中的作用靶点是什么？ 该项目将采用免疫定位以及超微结构和生物化学方法来研究斑马鱼胚胎中应激诱导的Hsp27和Hsp27磷酸丝氨酸突变体的再分布。这项工作的完成将大大推进对Hsp27在肌肉细胞中的调节和功能的理解。这些研究也有望促进对sHsp功能和肌肉细胞对应激和损伤的反应的一般理解，特别是在体内。这些知识可能最终用于增强肌肉生长，或改善商业或临床环境中的损伤和年龄依赖性肌肉功能障碍，并允许更好地理解变温（冷血）动物对环境应激的适应。此外，该项目将支持在当地的暑期科学夏令营计划中为地区小学和初中高中学生开展宣传和教育活动。

Small heat shock proteins (sHsps) are a large, but poorly understood, family of proteins. In vertebrates and many invertebrates, sHsps are constitutively found in muscle cells where they may play roles in homeostasis and injury repair. Preliminary results obtained in the Shelden laboratory have revealed striking, stress-dependent recruitment of the ubiquitous small heat shock protein, Hsp27, to muscle myofibrils. This research focuses on defining the mechanism and functional significance of this recruitment and specifically addresses the following questions: 1) How is Hsp27 regulated when it associates with myofibrils, and what is the effect of regulation on its function?, 2) What are the kinetics of association between Hsp27 and myofibrils during injury? and, 3) What is the target for Hsp27 within myofibrils? The project will employ immunolocalization as well as ulltrastructural and biochemical approaches to examine stress-induced redistribution of Hsp27 and phosphoserine mutants of Hsp27 in zebrafish embryos. Completion of this work will substantially advance the understanding of Hsp27 regulation and function in muscle cells. These studies are also expected to advance general understanding of sHsp functions and response of muscle cells to stress and injury, especially in vivo. Such knowledge may ultimately be used to enhance muscle growth, or ameliorate injury and age-dependent muscle dysfunction in commercial or clinical settings, and permit a better understanding of adaptations to environmental stress in poikilotherm (cold blooded) animals. In addition, the project will support outreach and educational activities to students in area elementary schools and junior and senior high school students at a local summer science camp program.