Casein kinase II-mediated phosphorylation regulates α-synuclein/synphilin-1 interaction and inclusion body formation
Casein kinase II-mediated phosphorylation regulates α-synuclein/synphilin-1 interaction and inclusion body formation
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DOI：
10.1074/jbc.m312760200
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发表时间：
2004-02-20
影响因子：
4.8
通讯作者：
Mouradian, MM
中科院分区：
文献类型：
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作者：
Lee, G;Tanaka, M;Mouradian, MM
α-突触核蛋白是一种磷蛋白，其作为帕金森病患者脑中路易体的主要组分而积累。也存在于Lewy小体中的Synphilin-1与α-突触核蛋白结合并在转染的细胞中形成细胞质内含物。然而，这种蛋白质-蛋白质相互作用的分子决定因素是未知的。在这里，我们报告说，酪蛋白激酶II（CKII）磷酸化synphilin-1和这种酶复合物的β亚基结合synphilin-1。此外，CKII α和β亚基均存在于过表达synphilin-1的细胞中的细胞质内含物内。值得注意的是，突触亲蛋白-1和α-突触核蛋白之间的相互作用显著依赖于磷酸化。5，6-二氯-β-D-呋喃核糖基苯并咪唑对CKII活性的抑制阻断了这两种蛋白质之间的结合，并显著降低了含有嗜酸性细胞质内含物的细胞的百分比。α-突触核蛋白（S129 A）中主要CKII磷酸化位点的突变对α-突触核蛋白和突触亲蛋白-1之间的结合或突触亲蛋白-1/α-突触核蛋白阳性包涵体的形成没有显著影响。这些数据表明，CKII介导的synphilin-1的磷酸化，而不是α-突触核蛋白的磷酸化是至关重要的，在调节他们的倾向，聚集成夹杂物。这些观察结果共同表明，一个普遍存在的翻译后修饰，如磷酸化，可以调节包涵体的α-突触核蛋白和synphilin-1相互作用的背景下形成。
alpha-Synuclein is a phosphoprotein that accumulates as a major component of Lewy bodies in the brains of patients with Parkinson disease. Synphilin-1, which is also present in Lewy bodies, binds with alpha-synuclein and forms cytoplasmic inclusions in transfected cells. Yet the molecular determinants of this protein-protein interaction are unknown. Here we report that casein kinase II (CKII) phosphorylates synphilin-1 and that the beta subunit of this enzyme complex binds to synphilin-1. Additionally, both CKII alpha and beta subunits are present within cytoplasmic inclusions in cells that overexpress synphilin-1. Notably, the interaction between synphilin-1 and alpha-synuclein is markedly dependent on phosphorylation. Inhibition of CKII activity by 5,6-dichlorol-beta-D-ribofuranosylbenzimidazole blocks the binding between these two proteins and significantly reduces the percentage of cells that contain eosinophilic cytoplasmic inclusions. Mutation of the major CKII phosphorylation site in alpha-synuclein (S129A) has no significant impact on the binding between alpha-synuclein and synphilin-1 or on the formation of synphilin-1/alpha-synuclein-positive inclusions. These data suggest that the CKII-mediated phosphorylation of synphilin-1 rather than that of alpha-synuclein is critical in modulating their tendency to aggregate into inclusions. These observations collectively indicate that a ubiquitous post-translational modification such as phosphorylation can regulate inclusion body formation in the context of alpha-synuclein and synphilin-1 interaction.