Proteasomal inhibition causes the formation of protein aggregates containing a wide range of proteins, including nitrated proteins
Proteasomal inhibition causes the formation of protein aggregates containing a wide range of proteins, including nitrated proteins
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DOI：
10.1046/j.1471-4159.2003.01841.x
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发表时间：
2003-07-01
影响因子：
4.7
通讯作者：
Jenner, P
中科院分区：
文献类型：
--
作者：
Hyun, DH;Lee, M;Jenner, P
Cu， zn -超氧化物歧化酶（SOD-1）突变与肌萎缩性侧索硬化症（ALS）的一些家族病例有关，但尚不清楚它们如何导致细胞死亡。我们研究了野生型SOD-1或G37R或G85R突变的过表达对泛素化和硝化蛋白积累的影响，以及蛋白酶体抑制剂乳糖蛋白酶引起的细胞活力丧失的影响。野生型SOD-1对蛋白酶体活性没有影响，但突变体使蛋白酶体活性有所降低。乳酸菌素（1mum）治疗仅引起有限的细胞活力丧失，尽管它诱导了蛋白酶体活性的明显抑制。然而，当细胞过表达突变体SOD-1时，对乳糖蛋白酶的反应导致细胞凋亡的生存能力丧失。当野生型和突变型SOD-1过表达时，对泛素化或硝化蛋白表现出免疫反应的细胞频率增加。在聚集体中观察到泛素化或硝化的α -微管蛋白、SOD-1、α -突触核蛋白和68K神经丝。在过表达突变体parkin （Del3-5， T240R和Q311'X）的细胞中观察到类似的聚集。一氧化氮合酶抑制剂l-NAME降低了活力丧失和聚集，表明蛋白质的硝化作用可能在聚集和伴随的细胞死亡中起重要作用。
Mutations in Cu,Zn-superoxide dismutase (SOD-1) are associated with some familial cases of amyotrophic lateral sclerosis (ALS), but it is not known how they result in cell death. We examined effects of overexpression of wild-type SOD-1 or the G37R or G85R mutations on the accumulation of ubiquitinated and nitrated proteins, and on loss of cell viability induced by the proteasome inhibitor, lactacystin. Wild-type SOD-1 had no effect on proteasomal activity, but the mutants decreased it somewhat. Treatment with lactacystin (1 mum) caused only limited cell viability loss, even though it induced a marked inhibition of proteasomal activities. However, viability loss due to apoptosis was substantial in response to lactacystin when cells were overexpressing a mutant SOD-1. The frequency of cells showing immunoreactivity against ubiquitinated- or nitrated-proteins was enhanced when wild-type and mutant SOD-1 s were overexpressed. Ubiquitinated or nitrated alpha-tubulin, SOD-1, alpha-synuclein and 68K neurofilaments were observed in the aggregates. Similar aggregates were observed in cells overexpressing mutant parkin (Del3-5, T240R and Q311'X). The nitric oxide synthase inhibitor, l-NAME, decreased viability loss and aggregation, suggesting that nitration of proteins may play an important role in aggregation and in the cell death accompanying it.