Phosphorylation of α-Synuclein Protein at Ser-129 Reduces Neuronal Dysfunction by Lowering Its Membrane Binding Property in Caenorhabditis elegans
Phosphorylation of α-Synuclein Protein at Ser-129 Reduces Neuronal Dysfunction by Lowering Its Membrane Binding Property in Caenorhabditis elegans
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DOI：
10.1074/jbc.m111.237131
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发表时间：
2012-03-02
影响因子：
4.8
通讯作者：
Iwatsubo, Takeshi
中科院分区：
文献类型：
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作者：
Kuwahara, Tomoki;Tonegawa, Reina;Iwatsubo, Takeshi
α -突触核蛋白是常染色体显性家族性帕金森病和伴路易体痴呆的病因，α -突触核蛋白Ser-129残基的磷酸化是帕金森病/伴路易体痴呆中检测到的关键翻译后修饰。然而，Ser-129磷酸化在帕金森病/路易体痴呆发病机制中的作用尚不清楚。本实验研究了ser -129取代α -突触核蛋白对转基因秀丽隐杆线虫（Tg蠕虫）突触核蛋白病模型的神经毒性。Tg虫泛神经元过表达非磷酸化(S129A) α -突触核蛋白显示严重缺陷，包括运动功能障碍、生长迟缓和突触异常。相比之下，表达磷酸化模拟物(S129D) α -突触核蛋白的Tg蠕虫表现出几乎正常的表型。生化分离表明，s129a - α -synuclein Tg虫的膜结合α -synuclein水平显著升高，而S129D-和a30p - α -synuclein的膜结合性能较低。此外，A30P/S129A双突变α -突触核蛋白不会引起神经元功能障碍，并且表现出低的膜结合特性。在人神经母细胞瘤SH-SY5Y细胞中，s129a - α -突触核蛋白在细胞膜上的定位显著增加。最后，S129A-Tg蠕虫的基因表达谱显示Daf-16/FOXO通路基因显著上调，这可能与s129a - α -突触核蛋白引起的功能障碍有关。这些结果表明Ser-129磷酸化的α -突触核蛋白通过降低膜结合特性来减弱α -突触核蛋白诱导的神经元功能障碍和下游应激反应。
alpha-Synuclein is causative for autosomal dominant familial Parkinson disease and dementia with Lewy bodies, and the phosphorylation of alpha-synuclein at residue Ser-129 is a key posttranslational modification detected in Parkinson disease/dementia with Lewy bodies lesions. However, the role of Ser-129 phosphorylation on the pathogenesis of Parkinson disease/dementia with Lewy bodies remains unclear. Here we investigated the neurotoxicity of Ser-129-substituted alpha-synuclein in the transgenic Caenorhabditis elegans (Tg worm) model of synucleinopathy. Tg worms pan-neuronally overexpressing nonphosphorylatable (S129A) alpha-synuclein showed severe defects including motor dysfunction, growth retardation, and synaptic abnormalities. In contrast, Tg worms expressing phosphorylation mimic (S129D) alpha-synuclein exhibited nearly normal phenotypes. Biochemical fractionation revealed that the level of membrane-bound alpha-synuclein was significantly increased in S129A-alpha-synuclein Tg worms, whereas S129D- as well as A30P-alpha-synuclein displayed lower membrane binding properties. Furthermore, A30P/S129A double mutant alpha-synuclein did not cause neuronal dysfunction and displayed low membrane binding property. In human neuroblastoma SH-SY5Y cells, localization of S129A-alpha-synuclein to membranes was significantly increased. Finally, gene expression profiling of S129A-Tg worms revealed a dramatic up-regulation of Daf-16/FOXO pathway genes, which likely act against the dysfunction caused by S129A-alpha-synuclein. These results imply a role of Ser-129 phosphorylation of alpha-synuclein in the attenuation of alpha-synuclein-induced neuronal dysfunction and downstream stress response by lowering the membrane binding property.