Comparison of two families with and without ataxia harboring novel variants in PRKCG
Comparison of two families with and without ataxia harboring novel variants in PRKCG
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DOI：
10.1038/s10038-022-01057-6
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发表时间：
2022-06-28
影响因子：
3.5
通讯作者：
Kawakami, Hideshi
中科院分区：
文献类型：
--
作者：
Tada, Yui;Kume, Kodai;Kawakami, Hideshi
脊髓小脑性共济失调14型（SCA 14）是一种常染色体显性SCA，由编码蛋白激酶C γ（PKC γ）的PRKCG变体引起。虽然毒性功能获得机制是SCA 14的主要原因，但其分子病理生理机制仍不清楚。为了阐明SCA 14的分子发病机制，我们分析了两个具有PRKCG变异的家族。两个日本家庭的临床症状和神经系统的研究结果进行了评估神经科医生。使用BGI平台进行外显子组测序。将携带鉴定的变体的GFP标记的PRKCG转染到HeLa细胞中，并使用共聚焦激光显微镜分析PKC γ的聚集。PKC γ的溶解度通过评估1% Triton-X中存在的不溶性部分的比例来评估。家族1的患者仅表现为小脑萎缩，无共济失调;然而，家族2的患者表现为小脑共济失调、肌张力障碍和比家族1更严重的小脑萎缩。外显子组测序鉴定了两个新的PRKCG错义变体：c.171 G > C，p.W57C（家族1）和c.400 T > C，p.C134R（家族2）。两种突变体PKC γ均聚集在细胞质中。尽管C134 R变体的PKC γ的溶解度低于野生型，但W57 C的PKC γ保持其溶解度。总之，我们鉴定了PRKCG的两种新变体。两个家族之间的严重程度差异可能是由于两种变体之间观察到的溶解度变化差异所致。PKC γ的溶解度降低可能在SCA 14的发病机制中起重要作用。
Spinocerebellar ataxia type 14 (SCA14) is an autosomal dominant SCA caused by variants of the PRKCG encoding protein kinase C gamma (PKC gamma). Although the toxic gain-of-function mechanism is the main cause of SCA14, its molecular pathophysiology remains unclear. To elucidate the molecular pathogenesis of SCA14, we analyzed two families with the variants inPRKCG. Clinical symptoms and neurological findings of two Japanese families were evaluated by neurologists. Exome sequencing was performed using the BGI platform. GFP-tagged PRKCGs harboring the identified variants were transfected into the HeLa cells, and aggregation of PKC gamma was analyzed using confocal laser microscopy. Solubility of PKC gamma was evaluated by assessing the proportion of insoluble fraction present in1% Triton-X. Patients in family 1 presented with only cerebellar atrophy without ataxia; however, patients in family 2 exhibited cerebellar ataxia, dystonia, and more severe cerebellar atrophy than those in family 1. Exome sequencing identified two novel missense variants of PRKCG:c.171 G > C,p.W57C (family 1), and c.400 T > C,p.C134R (family 2). Both the mutant PKC gamma aggregated in the cytoplasm. Although the solubility of PKC gamma of the C134R variant was lower than that of the wild-type, PKC gamma of W57C retained its solubility. In conclusion, we identified two novel variants of PRKCG. The difference in severity between the two families may be due to the difference in solubility changes observed between the two variants. Decreased solubility of the PKC gamma may play an important role in the pathogenesis of SCA14.