Functional Studies of Flightin, a Thick Filament Protein of Drosophila Flight Muscles

果蝇飞行肌粗丝蛋白 Flightin 的功能研究

• 批准号: 9728868
• 负责人: Jim Vigoreaux
• 金额: $ 29.98万
• 依托单位: University of Vermont & State Agricultural College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-04-15 至 2003-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9728868&HistoricalAwards=false
• 关键词: Functional; Studies; Flightin; Thick; Filament

9728868 Vigoreaux Lay Abstract The goal of this project is to determine the functional properties of flightin, a protein associated with the thick filaments of insect flight muscle. This protein is interesting because it may be involved in some of the special properties of this muscle, namely its very rapid beating. Unlike a typical vertebrate muscle cell which contracts and relaxes in a cycle coordinated with a rise and then fall in the concentration of intracellular calcium, insect flight muscle undergoes continuing rapid cycles of contraction and relaxation while the calcium concentration remains high. Flightin is found tightly associated with the myosin thick filaments of the insect cells. Flightin may simply stabilize the highly organized filament architecture in the cells or may be involved in a fundamentally different type of contraction control during the interaction of actin and myosin. Flightin or a relative may also be found in other muscle cell types where it may have very different or related functional properties. The project will address three specific questions to understand flightin function in the fruit fly, Drosophila melanogaster, chosen for its many advantages as a powerful model system. (1) Are mutant flight muscle cells that lack flightin less stable than normal cells when these cells contract? This would be expected if flightin plays a basic structural role to stabilize the highly ordered arrays of actin and myosin filament assemblies? (2) What is the precise way flightin interacts with the myosin filament? Detailed analysis of binding should elucidate how flightin might stabilize filament structure or control actin-myosin interaction since many details of the actin and myosin structures are already known. (3) What role does phosphorylation of the flightin molecule play in controlling its activity? Since the molecule can exist in phosphorylated and non-phosphorylated states, by analogy to other phosphorylated proteins whose state of phosphorylation c an be enzymatically controlled, it is very likely that these different states are also functionally different. The principal investigator, who was instrumental in the discovery of flightin, will purify flightin to study its binding properties, sites of phosphorylation, and other biochemical properties. He and his co-principal investigator will integrate results from a variety of other techniques and approaches, including electron microscopy, molecular and classical genetics, and physiological techniques, to provide clear and coherent answers to these questions. ***

9728868 Vigoreaux Lay这个项目的目标是确定Flightin的功能特性，Flightin是一种与昆虫飞行肌肉的粗丝相关的蛋白质。这种蛋白质很有趣，因为它可能与这块肌肉的一些特殊特性有关，即它的快速跳动。与典型的脊椎动物肌肉细胞在细胞内钙浓度上升和下降相协调的周期中收缩和放松不同，昆虫飞行肌肉在钙浓度保持较高的情况下经历持续快速的收缩和放松周期。Fliightin被发现与昆虫细胞的肌球蛋白粗丝紧密相关。Flightin可能只是稳定细胞中高度组织化的细丝结构，或者可能参与肌动蛋白和肌球蛋白相互作用过程中根本不同类型的收缩控制。在其他类型的肌肉细胞中也可以发现Flightin或其亲属，在这些类型的肌肉细胞中，它可能具有非常不同或相关的功能特性。该项目将解决三个具体的问题，以了解飞行蛋白在果蝇，果蝇，黑腹果蝇，选择作为一个强大的模式系统的许多优势。(1)缺乏飞行蛋白的突变飞行肌肉细胞在收缩时是否比正常细胞更不稳定？如果flightin在稳定肌动蛋白和肌球蛋白细丝组装的高度有序的阵列中发挥基本的结构作用，这是可以预期的？(2)flightin与肌球蛋白细丝相互作用的确切方式是什么？结合的详细分析应该阐明flightin如何稳定细丝结构或控制肌动蛋白-肌球蛋白的相互作用，因为肌动蛋白和肌球蛋白结构的许多细节已经知道。(3)Flightin分子的磷酸化在控制其活性方面起什么作用？由于分子可以以磷酸化和非磷酸化的状态存在，类似于其他磷酸化的蛋白质，其磷酸化状态可以通过酶来控制，所以这些不同的状态很可能在功能上也是不同的。这位首席研究员对flightin的发现起到了重要作用，他将提纯flightin，以研究其结合特性、磷酸化位置和其他生化特性。他和他的联合首席研究员将整合各种其他技术和方法的结果，包括电子显微镜、分子和经典遗传学以及生理学技术，为这些问题提供明确和连贯的答案。***