Spinocerebellar ataxia type 14 (SCA14) is an autosomal dominant neurodegenerative disorder characterized by cerebellar ataxia with myoclonus, dystonia, spasticity, and rigidity. Although missense mutations and a deletion mutation have been found in the protein kinase C gamma (PRKCG) gene encoding protein kinase C γ (PKCγ) in SCA14 families, a nonsense mutation has not been reported. The patho-mechanisms underlying SCA14 remain poorly understood. However, gain-of-function mechanisms and loss-of-function mechanisms, but not dominant negative mechanisms, were reported the patho-mechanism of SCA14. We identified the c.226C>T mutation of PRKCG, which caused the p.R76X in PKCγ by whole-exome sequencing in patients presenting cerebellar atrophy with cognitive and hearing impairment. To investigate the patho-mechanism of our case, we studied aggregation formation, cell death, and PKC inhibitory effect by confocal microscopy, western blotting with cleaved caspase 3, and pSer PKC motif antibodies, respectively. PKCγ(R76X)-GFP have aggregations the same as wild-type (WT) PKCγ-GFP. The PKCγ(R76X)-GFP inhibited PKC phosphorylation activity more than GFP alone. It also induced more apoptosis in COS7 and SH-SY5Y cells compared to WT-PKCγ-GFP and GFP. We first reported SCA14 patients with p.R76X in PKCγ who have cerebellar atrophy with cognitive and hearing impairment. Our results suggest that a dominant negative mechanism due to truncated peptides produced by p.R76X may be at least partially responsible for the cerebellar atrophy.

中文翻译：

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PRKCG基因无意义的突变导致14型脊髓小脑共济失调。

脊髓小脑性共济失调14型（SCA14）是常染色体显性遗传性神经退行性疾病，其特征是小脑性共济失调伴有肌阵挛，肌张力障碍，痉挛和僵硬。尽管在SCA14家族的蛋白激酶Cγ（PKCγ）的蛋白激酶Cγ（PRKCG）基因中发现了错义突变和缺失突变，但尚未报道无意义的突变。SCA14的病理机制仍知之甚少。然而，有报道称功能获得机制和功能丧失机制，而非显性负机制，不是SCA14的致病机制。我们鉴定了PRKCG的c.226C> T突变，该突变通过全外显子测序在呈现小脑萎缩并伴有认知和听力障碍的患者中引起PKCγ中的p.R76X。为了调查我们案件的病理机制，我们通过共聚焦显微镜，裂解的caspase 3和pSer PKC基序抗体分别研究了聚集形成，细胞死亡和PKC抑制作用。PKCγ（R76X）-GFP具有与野生型（WT）PKCγ-GFP相同的聚集。PKCγ（R76X）-GFP比单独的GFP抑制PKC磷酸化的活性更大。与WT-PKCγ-GFP和GFP相比，它在COS7和SH-SY5Y细胞中还诱导了更多的凋亡。我们首先报道了SCA14PKCγ中p.R76X的患者，其小脑萎缩伴有认知和听力障碍。我们的结果表明，由p.R76X产生的截短的肽引起的显性负性机制可能至少部分负责小脑萎缩。分别。PKCγ（R76X）-GFP具有与野生型（WT）PKCγ-GFP相同的聚集。PKCγ（R76X）-GFP比单独的GFP抑制PKC磷酸化的活性更大。与WT-PKCγ-GFP和GFP相比，它在COS7和SH-SY5Y细胞中还诱导了更多的凋亡。我们首先报道了SCA14PKCγ中p.R76X的患者，其小脑萎缩伴有认知和听力障碍。我们的结果表明，由p.R76X产生的截短的肽引起的显性负性机制可能至少部分负责小脑萎缩。分别。PKCγ（R76X）-GFP具有与野生型（WT）PKCγ-GFP相同的聚集。PKCγ（R76X）-GFP比单独的GFP抑制PKC磷酸化的活性更大。与WT-PKCγ-GFP和GFP相比，它在COS7和SH-SY5Y细胞中还诱导了更多的凋亡。我们首先报道了SCA14PKCγ中p.R76X的患者，其小脑萎缩伴有认知和听力障碍。我们的结果表明，由p.R76X产生的截短的肽引起的显性负性机制可能至少部分负责小脑萎缩。小脑萎缩伴认知和听力障碍的PKCγ中的R76X。我们的结果表明，由p.R76X产生的截短的肽引起的显性负性机制可能至少部分负责小脑萎缩。小脑萎缩伴认知和听力障碍的PKCγ中的R76X。我们的结果表明，由p.R76X产生的截短的肽引起的显性负性机制可能至少部分负责小脑萎缩。