Mass spectrometric analysis of accumulated TDP-43 in amyotrophic lateral sclerosis brains.
Mass spectrometric analysis of accumulated TDP-43 in amyotrophic lateral sclerosis brains.
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DOI：
10.1038/srep23281
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发表时间：
2016-03-16
影响因子：
4.6
通讯作者：
Hasegawa M
中科院分区：
文献类型：
--
作者：
Kametani F;Obi T;Shishido T;Akatsu H;Murayama S;Saito Y;Yoshida M;Hasegawa M
TDP-43是肌萎缩侧索硬化症(ALS)和伴有TDP-43病理相关泛素阳性包涵体的额颞叶变性(FTLD-TDP)的主要疾病相关蛋白。TDP-43聚集态的特征是异常的磷酸化、截断和胞浆错位，毒性异常的TDP-43的获得或生理性TDP-43功能的丧失被认为是神经变性的原因。然而，患者脑内异常TDP-43的大部分翻译后修饰或截断位点仍有待蛋白质化学分析鉴定。在这项研究中，我们对ALS患者脑中Sarkosyl不溶解的病理TDP-43进行了高灵敏的液-质联用分析，并确定了几个新的磷酸化位点、脱酰胺位点和切割位点。几乎所有的修饰都定位在富含甘氨酸的C-末端。在这项研究中发现的大多数切割位点都是新的，并且位于N-末端的一半，这表明这些位点可能更容易被蛋白水解酶访问。本研究获得的数据为TDP-43聚集和ALS发病的分子机制提供了基础。
TDP-43 is the major disease-associated protein involved in the pathogenesis and progression of amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration with ubiquitin-positive inclusions linked to TDP-43 pathology (FTLD-TDP). Abnormal phosphorylation, truncation and cytoplasmic mis-localization are known to be the characteristics for the aggregated forms of TDP-43, and gain of toxic abnormal TDP-43 or loss of function of physiological TDP-43 have been suggested as the cause of neurodegeneration. However, most of the post-translational modifications or truncation sites in the abnormal TDP-43 in brains of patients remain to be identified by protein chemical analysis. In this study, we carried out a highly sensitive liquid chromatography-mass spectrometry analysis of Sarkosyl-insoluble pathological TDP-43 from brains of ALS patients and identified several novel phosphorylation sites, deamidation sites, and cleavage sites. Almost all modifications were localized in the Gly-rich C-terminal half. Most of the cleavage sites identified in this study are novel and are located in N-terminal half, suggesting that these sites may be more accessible to proteolytic enzymes. The data obtained in this study provide a foundation for the molecular mechanisms of TDP-43 aggregation and ALS pathogenesis.