Spatial Regulation of Cytoskeletal Asymmetry

描述(申请人提供)：高等生物体中的细胞迁移对于多种生理和病理生理过程是必不可少的，包括胚胎发育和免疫反应。癌细胞的运动性改变是恶性肿瘤最危险的特征之一，因为它建立了肿瘤的侵袭和转移潜力。微管阵列的极化组织对于极化细胞的运动是必不可少的。然而，这一规定的原则还没有被理解。通常认为脊椎动物细胞中的微管是由中心体形成的。我们最近证明了大量的微管起源于高尔基体(Efimov等人，2007年)。我们已经确定了两个对这一新现象至关重要的分子成员：微管调节蛋白CLAP是形成高尔基体来源的微管所必需的，Golgin GCC185是高尔基体外围跨高尔基网络(TGN)上的CLAP的锚。与由中心体组成的对称微管阵列形成鲜明对比的是，在运动细胞中，在外围高尔基体室成核的微管优先朝向前缘。初步数据表明，缺乏高尔基体起源的微管的细胞的迁移潜力受到损害。在这个方案中，我们将检验高尔基体不对称微管成核对运动细胞极化至关重要的假设。我们将测试高尔基体起源的微管是否通过调节肌动蛋白细胞骨架或高尔基体后定向运输到细胞前沿，或两者兼而有之，对细胞极性产生影响。我们还将探讨调节TGN微管形成的分子机制。我们的具体目标是：1.确定高尔基体来源的微管在运动细胞的细胞骨架极性中的作用。2.确定高尔基体来源的微管在运动细胞极化高尔基体运输中的作用。3.确定动态卡环锚定是否是高尔基体微管组织潜力的基础。 公共卫生评论：细胞运动背后的分子事件的知识对于理解主要的健康相关过程至关重要，包括胚胎形态发生、伤口愈合、免疫反应和癌症侵袭。由于主要的抗癌治疗包括微管特异性药物，了解它们的潜在靶点尤其有价值。在这项提案中，我们将开展研究，以确定一种新的高尔基体衍生的非对称微管阵列在细胞运动中的作用。

DESCRIPTION (provided by applicant): Cell migration in higher organisms is essential for multiple physiological and pathophysiological processes, including embryonic development and immune responses. Alteration of cell motility in cancer cells is one of the most dangerous features of malignant tumors, as it builds up their invasive and metastatic potential. Polarized organization of microtubule arrays is essential for polarized cell motility. However, the principles of this regulation are not yet understood. It is generally assumed that microtubules in vertebrate cells are formed by the centrosome. We have recently demonstrated that a large number of microtubules originate from the Golgi apparatus (Efimov et al, 2007). We have identified two molecular players critical for this novel phenomenon: microtubule regulatory proteins CLASPs are required for the formation of Golgi-derived microtubules, and golgin GCC185 serves as an anchor for CLASPs at the trans-Golgi network (TGN) at the Golgi periphery. In sharp contrast to symmetric microtubule arrays organized by the centrosome, microtubules nucleated at the peripheral Golgi compartment are preferentially oriented toward the leading edge in motile cells. Preliminary data suggest that the migratory potential of cells lacking Golgi-originated microtubules is compromised. Within this proposal, we will test the hypothesis that asymmetric microtubule nucleation at the Golgi is critical for motile cell polarization. We will test whether Golgi-originated microtubules exert their effect on cell polarity via regulation of the actin cytoskeleton or directional post-Golgi transport to the cell front, or both. We will also address molecular mechanisms that regulate microtubule formation at the TGN. Our specific aims are: 1. Determine the role of Golgi-derived microtubules in the cytoskeletal polarity of motile cells. 2. Determine the role of Golgi-derived microtubules in polarized Golgi trafficking in motile cells. 3. Determine if dynamic CLASP anchoring underlies the microtubule-organizing potential of the Golgi. PUBLIC HEALTH REVELANCE: Knowledge of the molecular events that underlie cell motility is critical for understanding major health-related processes, including embryonic morphogenesis, wound healing, the immune response and cancer invasiveness. As major anticancer therapies include microtubule-specific drugs, knowledge their potential targets is especially valuable. In this proposal, we will carry out research that will determine the role of a novel Golgi-derived asymmetric microtubule array in cell motility.