The Regulation and Cellular Activities of the ARL2 GTPase

 描述(由申请人提供)：ARF调节GTP酶家族的成员在细胞信号传递中作为节点发挥作用，以协调基本的细胞过程，包括膜交通、能量代谢和细胞骨架。本申请的重点是其中一种GTP酶，ARL2及其结合伙伴。了解ARL2执行或调节基本细胞过程的分子机制将揭示对细胞生物学基本方面的新见解，并为干预人类疾病的进程提供潜在的靶点，包括但不限于癌症、心脏病、神经变性、视网膜退化和耳聋。在过去四年的资助期间，我们对真核细胞不同部分的ARL2作用的几个模型进行了严格的测试，丢弃了一些，提炼了另一些。我们还产生了许多关键试剂，包括第一批纯化的蛋白制剂，包括四种不同蛋白水平的镁和一系列ARL2的点突变，这些突变使我们能够剖析它在真核细胞中的不同关键作用。因此，我们准备在了解微管蛋白折叠和聚合的分子机制、线粒体中三磷酸腺苷的生成以及线粒体的分裂和运动方面取得更快的进展。在下一个资助期，我们提出了三个新的、具体的目标，这些目标是我们以前工作的合理扩展，但它们有望对细胞信号和调控的几个领域产生更广泛的影响。在目标1中，我们将测试 ARL2与微管蛋白特异的辅助伴侣辅因子D(TBCD)共同作用，调节微管的折叠、微管密度或聚合，而不是直接的细胞分裂。在Aim 2中，w将验证ARL2通过改变嵴重塑和线粒体融合来调节线粒体中的ATP产生的假设。在目标3中，我们研究了线粒体融合和运动性如何受到ARL2效应器和GAP ELMOD2的调节。

 DESCRIPTION (provided by applicant): Members of the ARF family of regulatory GTPases function as nodes in cell signaling to coordinate essential cell processes; including membrane traffic, energy metabolism, and the cytoskeleton. The focus of this application is one of those GTPases, ARL2, and its binding partners. An understanding of the molecular mechanisms of ARL2 action to carry out or regulate essential cell processes will reveal novel insights into fundamental aspects of cell biology as well as providing potential targets for intervention to alte the course of human diseases; including but not limited to cancer, heart disease, neurodegeneration, retinal degeneration, and deafness. During the previous four years of funding we have provided rigorous tests of several models for ARL2 actions in different parts of eukaryotic cells, discarding some and refining others. We have also generated many key reagents, including the first purified protein preparations of mg levels of four different proteins and a series of point mutations in ARL2 that allow dissection of its different essential roles in eukaryotic cells. Thus, we are poised to make much more rapid progress in our understanding of the molecular mechanisms of regulation of tubulin folding and polymerization, ATP generation in mitochondria, and mitochondrial fission and motility. In the next funding period we propose three new, specific aims that are logical extensions of our previous work but which promise to have a far broader impact on several fields of cell signaling and regulation. In aim 1 we will test the model that ARL2 acts with the tubulin-specific co-chaperone cofactor D (TBCD) to regulate tubulin folding, microtubule density or polymerization, and less directly cell division. In aim 2 w will test the hypothesis that ARL2 regulates ATP production in mitochondria via changes in cristae remodeling and mitochondrial fusion. And in aim 3 we examine how mitochondrial fusion and motility are regulated by the ARL2 effector and GAP, ELMOD2.