The Regulation and Cellular Activities of the ARL2 GTPase

 描述（由申请人提供）：调节性GTP酶ARF家族成员作为细胞信号传导中的节点发挥作用，以协调基本细胞过程;包括膜运输、能量代谢和细胞骨架。本申请的重点是这些GTP酶之一ARL 2及其结合伴侣。了解ARL 2进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，并为干预提供潜在靶点，以改变人类疾病的进程;包括但不限于癌症，心脏病，神经变性，视网膜变性和耳聋。在过去四年的资助中，我们对真核细胞不同部位的ARL 2作用的几种模型进行了严格的测试，丢弃了一些并改进了另一些。我们还产生了许多关键试剂，包括四种不同蛋白质的mg水平的第一种纯化蛋白质制剂和ARL 2中的一系列点突变，这些点突变允许解剖其在真核细胞中的不同基本作用。因此，我们准备在微管蛋白折叠和聚合、线粒体中ATP产生以及线粒体分裂和运动调节的分子机制的理解方面取得更快的进展。在下一个资助期内，我们提出了三个新的具体目标，这些目标是我们以前工作的逻辑延伸，但有望对细胞信号传导和调控的几个领域产生更广泛的影响。在aim 1中，我们将测试 ARL 2与微管蛋白特异性辅助分子伴侣辅因子D（TBCD）共同作用调节微管蛋白折叠、微管密度或聚合以及较少直接的细胞分裂的模型。在目标2中，我们将测试ARL 2通过嵴重塑和线粒体融合的变化来调节线粒体中ATP产生的假设。在目标3中，我们研究了ARL 2效应子和GAP，ELMOD 2如何调节线粒体融合和运动。

 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.