The regulation and cellular activities of the Arl2 GTPase

描述（由申请人提供）：Ras超家族中的调节性GTP酶的Arf家族出现在原核生物中，Arf家族的成员Arfs和Ar 12被认为是真核生物内共生起源中的关键组分。因此，它们被预测在所有真核生物的细胞生物学调节中具有重要作用。我们和其他人以前已经提供了Arl 2在细胞中微管生长中的作用的证据，但最近我们发现Arl 2在维持能量（ATP）水平中的专性作用，这被预测为它在真核生物中的基本作用。在本申请中，我建议开发Arl 2调节ATP水平的分子模型，以及埃尔莫（吞噬和细胞运动）家族中新发现的Arl 2 GAP/效应子的分子模型，这些模型调节线粒体和高尔基体形态。这项申请有三个具体目标。(1)确定Arl 2在维持ATP水平中的作用。(2)表征ELMOD 2差距域及其在线粒体中的作用，特别是其在线粒体形态中的作用。(3)确定ELMOD 1的特异性和功能。我假设ELMOD 1在细胞中作为ArfGAP发挥作用，可以减弱高尔基体上的Arf信号传导，并影响TGN上的膜交通，在TGN上它具有效应器特性。这些目标将共同提供一种古老的调节能量代谢方式的详细分子模型，这种方式可能存在于所有真核细胞中，与细胞分裂、细胞骨架和细胞核中基因转录的调节有关。这些研究有可能从根本上改变我们对与能量代谢、癌症、对癌症化疗药物的敏感性和基因转录有关的基本细胞过程的理解。 公共卫生相关性：维持适当的能量平衡对所有细胞的健康和功能至关重要，并且是线粒体的主要责任，线粒体是化学能（ATP）产生和氧消耗的场所。已知能量利用的巨大变化伴随着慢性疾病，包括癌症、神经退行性疾病和糖尿病。我们已经发现了新的信号传导途径，参与调节细胞ATP水平和线粒体和高尔基体区室的形态，这些区室与古老且高度保守的调节性GT3 Arl 2有关。在本申请中，我提出了三个具体的目标，将阐明分子机制的Arl 2和Arl 2 GTdR激活蛋白的行动，作为调节ATP的生产，线粒体形态，高尔基体的完整性与预测的联系，细胞分裂和细胞骨架。

DESCRIPTION (provided by applicant): The Arf family of regulatory GTPases, within the Ras superfamily, emerged in prokaryotes and members of the Arf family, Arfs and Arl2, have been implicated as critical components in the endosymbiotic origins of eukaryotes. As such they are predicted to have essential roles in the regulation of cell biology in all eukaryotes. We and others have previously provided evidence for a role for Arl2 in microtubule growth in cells but more recently we have discovered an obligate role for Arl2 in maintenance of energy (ATP) levels that is predicted to be its fundamental role in eukaryotes. In this application I propose to develop molecular models of Arl2 regulation of ATP levels, as well as for the newly identified Arl2 GAPs/effectors in the ELMO (Engulfment and cell motility) family, that regulate mitochondria and Golgi morphology. This application has three specific aims. (1) Determine the role of Arl2 in maintenance of ATP levels. (2) Characterize the GAP domain of ELMOD2 and its actions in mitochondria including specifically its role in mitochondrial morphology. (3) Determine the specificity and functions of ELMOD1. I hypothesize that ELMOD1 acts in cells as an ArfGAP that can attenuate Arf signaling at the Golgi and impact membrane traffic also at the TGN, where it has effector properties. Together these aims will provide detailed molecular models of an ancient means of regulating energy metabolism in perhaps all eukaryotic cells, with ties to cell division, the cytoskeleton, and the regulation of gene transcription in the nucleus. These studies have the potential to fundamentally alter our understanding of essential cellular processes with ties to energy metabolism, cancer, sensitivity to cancer chemotherapeutics, and gene transcription. PUBLIC HEALTH RELEVANCE: Maintenance of proper energy balance is essential to the health and function of all cells and is the primary responsibility of mitochondria, the site of chemical energy (ATP) generation and oxygen consumption. Dramatic changes in energy utilization are known to accompany chronic diseases including cancer, neurodegenerative diseases, and diabetes. We have discovered novel signaling pathways that are involved in regulating cellular ATP levels and the morphology of the mitochondria and Golgi compartments that are tied to the ancient and highly conserved regulatory GTPase Arl2. In this application I propose three specific aims that will elucidate molecular mechanisms of Arl2 and Arl2 GTPase activating protein actions as regulators of ATP production, mitochondria morphology, and Golgi integrity with predicted links to cell division and the cell cytoskeleton.