The role of G3BP1 in mutant SOD1-mediated familial ALS

摘要 肌萎缩侧索硬化症，也被称为Lou Gehrig病或ALS，是一种进行性和致命性的 无法治愈的神经退行性疾病。为了制定有效的预防措施或治疗方法， 我们必须更好地了解ALS的分子发病机制。肌萎缩侧索硬化的一个普遍症状是 运动神经元丢失引起的肌肉萎缩。家族性肌萎缩侧索硬化症是由遗传基因引起的 突变。第一个被发现突变导致肌萎缩侧索硬化症的基因编码了铜/锌超氧化物 歧化酶SOD1.目前还不完全清楚SOD1的突变是如何导致ALS的毒性的。其他几个 突变导致肌萎缩侧索硬化症的基因编码RNA新陈代谢调节器，其已知功能似乎是 与SOD1无关。这两条致病途径在肌萎缩侧索硬化症中的趋同尚不清楚。 已知的Ras GTP酶激活蛋白结合蛋白G3BP1调节细胞的稳定性和 信使RNA的翻译。它也是应力颗粒动力学的关键调节器。应激颗粒形态 以应对氧化应激和热休克等挑战。应激颗粒暂时隔离 翻译不活跃形式的可有可无的信使RNA，释放核糖体用于翻译 在压力下生存必不可少的成绩单。 SOD1的ALS突变体形成细胞质内含物。我们发现突变的SOD1包裹体 含有G3BP1。我们还发现突变体SOD1和G3BP1之间存在RNA不依赖的相互作用。我们的 假设G3BP1代表了SOD1中ALS突变和 核糖核酸代谢的病理改变。 拨款提案的目标1将确定ALS突变体SOD1-G3BP1的分子细节 细胞培养和体外模型中的相互作用。目标2将确定SOD1的ALS突变体对应激的影响 细胞培养和转基因小鼠模型中颗粒动力学和G3BP1 RNA结合。目标3将测试 G3BP1和果蝇G3BP1同源物Rasputin/Rin在转基因人SOD1毒性中的作用 飞行模特。这些发现有望为SOD1突变的机制提供重要的见解 造成毒性和干扰RNA新陈代谢。

Abstract Amyotrophic lateral sclerosis, also known as Lou Gehrig's disease or ALS is a progressive and fatal neurodegenerative disease with no cure available. In order to develop effective preventive measures or cures, we have to gain a better understanding of the molecular pathogenesis of ALS. A general symptom of ALS is muscle wasting caused by motor neuron loss. In familial ALS, the disease is caused by inherited gene mutations. The first gene whose mutations were identified to cause ALS encodes the Cu/Zn superoxide dismutase SOD1. It is still not fully understood how the mutations in SOD1 cause toxicity in ALS. Several other genes whose mutations cause ALS encode RNA metabolism regulators whose known functions are seemingly unrelated to that of SOD1. The convergence of these two pathogenic pathways in ALS is still unclear. The Ras GTPase-activating protein-binding protein G3BP1 is known to regulate the stability and translation of messenger RNAs. It is also a critical regulator of stress granule dynamics. Stress granules form in response to challenges such as oxidative stress and heat shock. Stress granules sequester temporarily dispensable messenger RNAs in translationally inactive form, freeing up ribosomes for the translation of transcripts that are essential to survive the stress. ALS mutants of SOD1 form cytoplasmic inclusions. We found that the mutant SOD1 inclusions contained G3BP1. We also found an RNA independent interaction between mutant SOD1 and G3BP1. Our hypothesis is that G3BP1 represents a critical link between the ALS mutations in SOD1 and the pathological alterations in RNA metabolism. Aim 1 of the grant proposal will determine the molecular details of the ALS mutant SOD1-G3BP1 interaction in cell culture and in vitro models. Aim 2 will determine the effect of ALS mutants of SOD1 on stress granule dynamics and G3BP1 RNA binding in cell culture and transgenic mouse models. Aim 3 will test the role of G3BP1 and the Drosophila G3BP1 homolog Rasputin/Rin in the toxicity of transgenic human SOD1 in a fly model. The findings are expected to provide important insight into the mechanism by which SOD1 mutations cause toxicity and perturb RNA metabolism.