Regulation of Microtubule Motors

描述（由申请人提供）：细胞器和大分子复合物通过细胞质的运输对于每个真核细胞都是必不可少的。这个过程是由马达蛋白完成的，马达蛋白利用ATP水解的能量沿着微管和肌动蛋白丝移动许多类型的货物。运动依赖性运输的空间和时间控制对于细胞分裂、细胞器运输和定位以及mRNA和蛋白质复合物在细胞质中的移动至关重要。细胞器运输和马达相关蛋白的缺陷促成或引起许多神经退行性疾病，并且马达驱动的染色体分离中的错误可引起异常发育和癌症。该提案的目标是了解微管马达的运动是如何由辅助蛋白调节的，以及沿着微管的运动如何产生细胞极性。对于调节运动的蛋白质的分析，我们将使用培养的果蝇S2细胞，因为它们对通过RNAi的蛋白质敲低高度敏感，并且货物沿着微管的运动不受其他细胞骨架元件的干扰。为了分析细胞极性，我们将使用果蝇神经元的原代培养物，其中微管和微管马达是轴突和树突生长所需的关键组分。该提案的具体目标是：（一）确定运输如何受局部信号（微管结合蛋白）的调节。(ii)发现与微管无关的蛋白质对运输调节的贡献。（iii）利用神经元模型研究微管和微管依赖的运输如何形成细胞过程。

DESCRIPTION (provided by applicant): Transport of organelles and macromolecular complexes through the cytoplasm is essential for every eukaryotic cell. This process is performed by motor proteins that use the energy of ATP hydrolysis to move many types of cargo along microtubules and actin filaments. The spatial and temporal control of motor-dependent transport is critical for cell division, organelle transport and positioning, and the movement of mRNA and protein complexes in the cytoplasm. Defects in organelle transport and motor-associated proteins contribute or cause many neurodegenerative diseases, and mistakes in motor- driven chromosome segregation can cause abnormal development and cancer. The goal of this proposal is to understand how movement of microtubule motors is regulated by accessory proteins and how movement along microtubules generates cell polarity. For analysis of proteins regulating the movement we will use cultured Drosophila S2 cells because they are highly sensitive to protein knock-down by RNAi and movement of cargo along microtubules is not perturbed by other cytoskeletal elements. For analysis of cell polarity we will use primary cultures of Drosophila neurons where microtubules and microtubule motors are key components required for growth of axons and dendrites. The specific aims of the proposal are: (i) To establish how transport is regulated by local signals (microtubule-binding proteins). (ii) To find contribution of proteins that are not associated with microtubules to transport regulation (iii) To use neuronal model to find how microtubules and microtubule-dependent transport generate formation of cell processes.