Liu Chao, Fei Erkang, Jia Nali, Wang Hongfeng, Tao Ruisong, Iwata Atsushi, Nukina Nobuyuki, Zhou Jiangning, Wang Guanghui
Hefei National Laboratory for Physical Sciences at Microscale and Department of Neurobiology, School of Life Sciences, University of Science & Technology of China, Hefei, Anhui, China.
J Biol Chem. 2007 May 11;282(19):14558-66. doi: 10.1074/jbc.M700422200. Epub 2007 Mar 14.
alpha-Synuclein (alpha-syn) and ubiquitin (Ub) are major protein components deposited in Lewy bodies (LBs) and Lewy neurites, which are pathologic hallmarks of idiopathic Parkinson disease (PD). Almost 90% of alpha-syn in LBs is phosphorylated at serine 129 (Ser(129)). However, the role of Ser(129)-phosphorylated alpha-syn in the biogenesis of LBs remains unclear. Here, we show that compared with coexpression of wild type (WT)alpha-syn and Ub, coexpression of phospho-mimic mutant alpha-syn (S129D) and Ub in neuro2a cells results in an increase of Ub-conjugates and the formation of ubiquitinated inclusions. Furthermore, S129D alpha-syn fails to increase the Ub-conjugates and form ubiquitinated inclusions in the presence of a K63R mutant Ub. In addition, as compared with WT alpha-syn, S129D alpha-syn increased cytoplasmic and neuritic aggregates of itself in neuro2a cells treated with H(2)O(2) and serum deprivation. These results suggest that the contribution of Ser(129)-phosphorylated alpha-syn to the Lys(63)-linked Ub-conjugates and aggregation of itself may be involved in the biogenesis of LBs in Parkinson disease and other related synucleinopathies.
α-突触核蛋白（α-syn）和泛素（Ub）是沉积在路易小体（LBs）和路易神经突中的主要蛋白质成分，而路易小体和路易神经突是特发性帕金森病（PD）的病理标志。路易小体中近90%的α-突触核蛋白在丝氨酸129（Ser(129)）处被磷酸化。然而，Ser(129)磷酸化的α-突触核蛋白在路易小体生物发生中的作用仍不清楚。在此，我们表明，与野生型（WT）α-突触核蛋白和泛素共表达相比，在Neuro2a细胞中共表达磷酸模拟突变体α-突触核蛋白（S129D）和泛素会导致泛素缀合物增加以及泛素化包涵体的形成。此外，在存在K63R突变体泛素的情况下，S129D α-突触核蛋白无法增加泛素缀合物并形成泛素化包涵体。另外，与WT α-突触核蛋白相比，在用H(2)O(2)和血清剥夺处理的Neuro2a细胞中，S129D α-突触核蛋白增加了其自身的细胞质和神经突聚集物。这些结果表明，Ser(129)磷酸化的α-突触核蛋白对赖氨酸63连接的泛素缀合物及其自身聚集的贡献可能参与帕金森病和其他相关突触核蛋白病中路易小体的生物发生。
