RUI: Characterization of a Molecular Chaperone in the Eukaryotic Flagellum

70000 M.W.热休克蛋白（HSP70）家族的分子伴侣是一种特殊的蛋白质，它与细胞中许多其他类型的蛋白质相互作用，以帮助它们正确折叠和组装。已知需要HSP70功能的生物过程包括应激反应、蛋白质靶向和分泌、类固醇激素受体的组装、病毒复制和基因转录的启动等多种例子。最近的证据表明，HSP70伴侣家族的成员参与了更大的细胞内结构的构建，如微管细胞骨架。在对含有微管的细胞器组装的调查中，真核绿藻衣藻的鞭毛，发现了一个HSP70家族成员。免疫荧光定位实验表明，该HSP70蛋白集中在鞭毛尖端。这种定位是重要的，因为以前的工作已经表明，尖端是鞭毛组装的地点。分子、细胞学和细胞生物学技术的结合将被用来进一步表征这种分子伴侣的体内作用。这项研究为研究活细胞中细胞骨架组装的过程提供了重要的机会。由于鞭毛存在于包括人体细胞在内的许多不同类型的细胞上，因此对衣藻的研究应该揭示大分子组装的保守过程的细节，这些过程适用于理解其他含有微管结构的形成，如有丝分裂纺锤体或间期微管细胞骨架。活细胞是动态的系统，包含赋予它们形式和形状的建筑元素。这些结构必须在适当的时间和地点进行组装和拆卸，以便细胞正常工作。这项研究考察了一种叫做“chape rone”的特殊蛋白质在这一过程中可能发挥的作用。该项目将进一步加深我们对正常细胞功能的理解，并解决生命中的关键机制。＊＊＊

MCB 9506236 Karl Johnson Molecular chaperones of the 70,000 M.W. Heat Shock Protein (HSP70) family are special proteins that interact with many other types of proteins in cells to assist both their proper folding and assembly. Biological processes known to require HSP70 function include such diverse examples as response to stress, protein targeting and secretion, assembly of steroid hormone receptors, viral replication and the initiation of gene transcription. Recent evidence implicates members of the HSP70 chaperone family in the construction of larger intracellular structures such as the microtubule cytoskeleton. During an investigation into the assembly of a microtubule-containing organelle, the eukaryotic flagellum of the green alga Chlamydomonas, an HSP70 family member was identified. Immunofluorescent localization experiments demonstrated that this HSP70 protein was concentrated in the tips of flagella. This localization is significant, as previous work has shown that the tips are the sites of flagellar assembly. A combination of molecular, cytological and cell biological techniques will be employed to further characterize the in vivo role of this molecular chaperone. This investigation offers significant opportunities for novel insight into the processes which govern cytoskeletal assembly in living cells. Because flagella are present on many different cell types, including cells of the human body, investigations in the green alga Chlamydomonas should reveal details about conserved processes of macromolecular assembly applicable to understanding the formation of other microtubule-containing structures, such as the mitotic spindle or interphase microtubule cytoskeleton. %%% Living cells are dynamic systems that contain architectural elements that give them form and shape. These structures must be assembled and disassembled at appropriate times and places in order for the cells to function properly. This investigation examines the role a special kind of protein called a "chape rone" may play in this process. This project should further our understanding of normal cellular functions and address a key mechanism in life. ***