Regulation and Function of Hsp27 in Zebrafish

小热休克蛋白（sHsps）是一个庞大的，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，它们可能在体内平衡和损伤修复中发挥作用。在谢尔登实验室获得的初步结果显示，普遍存在的小热休克蛋白Hsp27在肌肉肌原纤维上的招募具有显著的应力依赖性。本研究侧重于明确这种募集的机制和功能意义，具体解决以下问题：1)Hsp27与肌原纤维结合时是如何调控的，调控对其功能的影响是什么？2)损伤时Hsp27与肌原纤维的关联动力学是怎样的？3)肌原纤维中Hsp27的靶点是什么？该项目将采用免疫定位、超微结构和生化方法来检测应激诱导的热休克蛋白27和热休克蛋白27的磷酸丝氨酸突变体在斑马鱼胚胎中的重新分布。这项工作的完成将大大促进对Hsp27在肌肉细胞中的调控和功能的理解。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普遍理解，特别是在体内。这些知识可能最终用于促进肌肉生长，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动物（冷血动物）对环境压力的适应。此外，该项目还将支持向当地小学学生和参加当地暑期科学营项目的初高中学生提供宣传和教育活动。

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.