A novel EPM2A mutation yields a slow progression form of Lafora disease.
A novel EPM2A mutation yields a slow progression form of Lafora disease.
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DOI：
10.1016/j.eplepsyres.2018.07.003
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发表时间：
2018-09
影响因子：
2.2
通讯作者：
Sanz P
中科院分区：
文献类型：
--
作者：
Garcia-Gimeno MA;Rodilla-Ramirez PN;Viana R;Salas-Puig X;Brewer MK;Gentry MS;Sanz P
Lafora病（LD, OMIM 254780）是一种罕见的疾病，以癫痫和神经退行性变为特征，通常在出现最初症状后的第一个十年内导致患者进入植物人状态并死亡。在绝大多数情况下，LD与EPM2A基因（编码葡聚糖磷酸酶去甲素）或EPM2B基因（编码e3 -泛素连接酶malin）的突变有关。在这项工作中，我们描述了EPM2A基因中存在的突变，该突变在患者中表现出缓慢的疾病进展形式。患者为复合杂合子，对应等位基因有Y112X和N163D突变。在从患者身上获得的原代成纤维细胞中，我们通过实时定量PCR分析了突变等位基因的表达，发现EPM2A基因的表达水平略低于对照细胞。然而，通过Western blotting，我们无法检测患者成纤维细胞粗提取物中的内源性蛋白质水平。Y112X突变会导致缺乏磷酸酶结构域的截断蛋白，并可能被降解。由于微量的laforin-N163D可能仍在细胞生理学中发挥作用，我们分析了N163D突变的生化特性。我们发现重组去甲虫素N163D蛋白与野生型一样稳定，并且对生物学相关底物表现出接近野生型的磷酸酶活性。相反，它显示出与先前确定的劳力素结合伙伴的相互作用谱的严重损害。这些结果使我们得出结论，该患者的疾病进展缓慢可能是由于去甲肾上腺素N163D的特定生化特性或与致病性分离的其他遗传修饰因素的存在。
Lafora disease (LD, OMIM 254780) is a rare disorder characterized by epilepsy and neurodegeneration leading patients to a vegetative state and death, usually within the first decade from the onset of the first symptoms. In the vast majority of cases LD is related to mutations in either the EPM2A gene (encoding the glucan phosphatase laforin) or the EPM2B gene (encoding the E3-ubiquitin ligase malin). In this work, we characterize the mutations present in the EPM2A gene in a patient displaying a slow progression form of the disease. The patient is compound heterozygous with Y112X and N163D mutations in the corresponding alleles. In primary fibroblasts obtained from the patient, we analyzed the expression of the mutated alleles by quantitative real time PCR and found slightly lower levels of expression of the EPM2A gene respect to control cells. However, by Western blotting we were unable to detect endogenous levels of the protein in crude extracts from patient fibroblasts. The Y112X mutation would render a truncated protein lacking the phosphatase domain and likely degraded. Since minute amounts of laforin-N163D might still play a role in cell physiology, we analyzed the biochemical characteristics of the N163D mutation. We found that recombinant laforin N163D protein was as stable as wild type and exhibited near wild type phosphatase activity towards biologically relevant substrates. On the contrary, it showed a severe impairment in the interaction profile with previously identified laforin binding partners. These results lead us to conclude that the slow progression of the disease present in this patient could be either due to the specific biochemical properties of laforin N163D or to the presence of alternative genetic modifying factors separate from pathogenicity.
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影响因子：
10.5
作者：
Cheng, Alan;Zhang, Mei;Saltiel, Alan R.
通讯作者：
Saltiel, Alan R.
影响因子：
2.2
作者：
Jara-Prado, Aurelio;Ochoa, Adriana;Martinez-Juarez, Iris E.
通讯作者：
Martinez-Juarez, Iris E.
DOI：
10.1073/pnas.95.11.6245
发表时间：
1998-05-26
影响因子：
11.1
作者：
Ludin, K;Jiang, R;Carlson, M
通讯作者：
Carlson, M
影响因子：
3.2
作者：
ITO, H;FUKUDA, Y;KIMURA, A
通讯作者：
KIMURA, A
影响因子：
5.6
作者：
Franceschetti, S;Gambardella, A;Zara, F
通讯作者：
Zara, F