Regulation of mitochondrial function by ARL2 and its putative effector ELMOD2

ARL2 及其推定效应子 ELMOD2 对线粒体功能的调节

• 批准号: 8974730
• 负责人: Laura Elizabeth Newman
• 金额: $ 4.36万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-12-01 至 2017-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8974730
• 关键词: ARL2 gene; Abnormal Cell; Affect; Animal Model; Binding; Biological Assay; Biology; Blindness; Cell Death; Cell physiology; Cells; Crista ampullaris; Defect; Disease; Dominant-Negative Mutation; Electron Microscopy; Electron Transport; Essential Genes; Family; GTPase-Activating Proteins; Gene Proteins; Genetic Screening; Guanosine Triphosphate Phosphohydrolases; Health; Heart Diseases; Human; Inner mitochondrial membrane; Knowledge; Lead; Link; Location; Maintenance; Malignant Neoplasms; Membrane Fusion; Microtubules; Mitochondria; Mitochondrial Crista; Mitochondrial Matrix; Modeling; Monomeric GTP-Binding Proteins; Morphology; Neurodegenerative Disorders; Normal Cell; OPA1 gene; Organelles; Pathway interactions; Phenocopy; Phenotype; Play; Process; Production; Proteins; Regulation; Retinal Degeneration; Role; Series; Signal Pathway; Signal Transduction; Site; Small Interfering RNA; Testing; Work; cell motility; genetic regulatory protein; human disease; knock-down; loss of function; member; mitochondrial dysfunction; mitochondrial metabolism; mutant; research study; response

DESCRIPTION (provided by applicant): Mitochondria are important and dynamic organelles that produce energy for the cell, and mitochondrial defects underlie several human diseases. We have found that loss of the small GTPase ARL2 severely impairs mitochondrial function. Specifically, loss of ARL2 activity causes defects in mitochondrial morphology, motility, and ATP production. We have also found that knockdown of an ARL2 GTPase activating protein (GAP), ELMOD2, also causes defects in morphology, motility, and ATP production. Because both ARL2 and ELMOD2 localize to the mitochondrial matrix, can bind to each other, and produce the same phenotypes upon knockdown, they are likely members of an important mitochondrial signaling pathway. Additionally, loss of ARL2 and ELMOD2 phenocopy the loss of OPA1, an important regulator of cristae, which are critical for mitochondrial ATP production. Therefore, I hypothesize that ARL2 signaling through ELMOD2 in the mitochondrial matrix is required for proper maintenance of mitochondrial morphology, motility, and ATP production, through regulation of cristae morphology. In Aim 1 I will determine if matrix-targeted ARL2 and ELMOD2 can rescue the mitochondrial defects resulting from ARL2 and ELMOD2 knockdown, which will test my model that ARL2 and ELMOD2 act from within the matrix. To test if ELMOD2 acts as an ARL2 effector, I will generate point mutants of ARL2 that cannot bind ELMOD2, which will determine if ARL2 binding to ELMOD2 is required for its mitochondrial functions. I will also use a GAP dead ELMOD2 mutant, ELMOD2[R167K], to determine if ELMOD2 GAP activity for ARL2 is required for mitochondrial function. In Aim 2 I will use electron microscopy to determine the sub-mitochondrial localization of ARL2 and ELMOD2, and test my hypothesis that their knockdown alters cristae morphology. Studying these evolutionarily conserved proteins will inform us about proper mitochondrial function, which can be used for the study of many human diseases.

描述（由申请人提供）：线粒体是为细胞产生能量的重要且动态的细胞器，线粒体缺陷是多种人类疾病的根源。我们发现小 GTPase ARL2 的缺失会严重损害线粒体功能。具体来说，ARL2 活性的丧失会导致线粒体形态、运动和 ATP 产生的缺陷。我们还发现，ARL2 GTP 酶激活蛋白 (GAP) ELMOD2 的敲除也会导致形态、运动和 ATP 产生的缺陷。由于 ARL2 和 ELMOD2 都定位于线粒体基质，可以相互结合，并在敲低后产生相同的表型，因此它们可能是重要的线粒体信号通路的成员。此外，ARL2 和 ELMOD2 的缺失会导致 OPA1 的缺失，OPA1 是嵴的重要调节因子，对线粒体 ATP 的产生至关重要。因此，我假设通过线粒体基质中的 ELMOD2 进行 ARL2 信号传导是通过调节嵴形态来适当维持线粒体形态、运动和 ATP 产生所必需的。在目标 1 中，我将确定基质靶向的 ARL2 和 ELMOD2 是否可以挽救因 ARL2 和 ELMOD2 敲低而导致的线粒体缺陷，这将测试我的模型，即 ARL2 和 ELMOD2 在基质内发挥作用。为了测试 ELMOD2 是否充当 ARL2 效应子，我将生成无法结合 ELMOD2 的 ARL2 点突变体，这将确定 ARL2 与 ELMOD2 结合是否是其线粒体功能所必需的。我还将使用 GAP 死亡 ELMOD2 突变体 ELMOD2[R167K] 来确定 ARL2 的 ELMOD2 GAP 活性是否是线粒体功能所必需的。在目标 2 中，我将使用电子显微镜来确定 ARL2 和 ELMOD2 的线粒体下定位，并检验我的假设，即它们的敲低会改变嵴形态。研究这些进化上保守的蛋白质将告诉我们适当的线粒体功能，这可用于研究许多人类疾病。