Structure And Function Of Cytoplasmic Motors

交通运输项目 鱿鱼巨型轴突是了解轴突运输的重要模型。传统的动蛋白是在鱿鱼中发现的一组不同的、具有重要功能的分子马达蛋白的创始成员，它在那里的作用归因于轴突中小泡的运输。最近，我们完成了一个EST(表达序列标签)项目，旨在识别鱿鱼神经系统中的其他马达。我们发现了83个重叠序列，编码5个细胞肌球蛋白(非肌肉)，3个动力蛋白重链和6个新的动蛋白。其中一种新的激动素(K-165)与轴浆细胞器分离，仅在细胞器与轴突内的微管交界处发现。这种Kinesin，一种Kinesin-3，似乎实际上是负责轴突运输的马达，尽管Kinesin-1可能也起到了作用。除了新的马达，EST项目还发现了与神经系统疾病有关的基因。这包括淀粉样前体蛋白(APP)，一种在阿尔茨海默病(AD)中起作用的跨膜蛋白，以及两个与尼曼·皮克病有关的基因。这一EST资源已经与17个研究鱿鱼的实验室共享，以研究基础和生物医学研究。我们还使用了我们开发的一种新技术，用可光激活的绿色荧光蛋白-肌动蛋白标记肌动蛋白细胞骨架中的纤维亚群。这项技术可以观察到肌动蛋白的横向运动，同时伴随着β1整合素的同步横向运动和聚集。这些结果表明，肌动蛋白定位激活整合素，为细胞寻找新的黏附位置和首选的迁移方向提供了一种机制。

TRANSPORT PROJECT The squid giant axon is an important model for understanding axonal transport. Conventional kinesin, the founding member of a diverse and functionally important group of molecular motor proteins, was discovered in squid and its role there attributed to the transport of vesicles in axons. Recently we have completed an EST (Expressed Sequence Tag) project aimed at identifying other motors in the squid nervous system. We found 83 overlapping sequences that encode five cellular myosins (non-muscle), three dynein heavy chains, and six new kinesins. One of the new kinesins (K-165) fractionates with axoplasmic organelles, and is found only at organelle interfaces with microtubules in the axon. This kinesin, a Kinesin-3, appears to be the motor actually responsible for axonal transport, though Kinesin-1 may make a contribution as well. In addition to new motors, the EST project has identified genes implicated in neurological disease. This includes Amyloid Precursor Protein (APP), a transmembrane protein with a role in Alzheimer's Disease (AD), and two genes involved in Niemann Pick Disease. This EST resource has been shared with seventeen laboratories working on squid to study basic and biomedical research. We also used a new technique we developed to label a subpopulation of the fibers in the actin cytoskeleton with photoactivatable-EGFP-actin. This technique allowed lateral motions of actin accompanied by synchronous lateral movement and clustering of beta 1 integrins to be observed. These results suggest that actin positioning activates integrins to provide a mechanism for cells to seek new adhesion sites and preferred directions of migration.