PrP (122?139) is a covert mitochondrial targeting signal of prion protein and it specifically triggers the perinuclear clustering of mitochondria in neuronal culture cells
PrP (122?139) is a covert mitochondrial targeting signal of prion protein and it specifically triggers the perinuclear clustering of mitochondria in neuronal culture cells
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PrP (122?139) 是朊病毒蛋白的隐蔽线粒体靶向信号，它特异性触发神经元培养细胞中线粒体的核周聚集
DOI：
10.1016/j.bbrc.2020.01.099
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发表时间：
2020
影响因子：
3.1
通讯作者：
Hachiya Naomi
中科院分区：
文献类型：
--
作者：
Shimizu Takuto;Kozuka Yoshimichi;Kusano Mayumi;Nagane Masaki;Yamashita Tadashi;Hachiya Naomi
在许多神经退行性疾病中，线粒体积极参与疾病的发作和/或进展，因为神经元细胞的能量消耗直接导致细胞的功能障碍和退化。在朊病毒疾病的情况下，线粒体参与最近已被报道，朊病毒蛋白（PrP）定位于线粒体的证据正在增加。尽管有这些发现，PrP靶向线粒体的精确分子机制仍不清楚。PrP是一种分泌性蛋白，不具有靶向线粒体的前序列，因此我们认为PrP的氨基酸序列中存在一个隐蔽信号。为了找到序列，我们构建了各种GFP融合的PrP截短体，并通过活细胞成像验证了与线粒体的共定位。因此，我们发现18个氨基酸，PrP（122-139），是必不可少的线粒体靶向的PrP。此外，荧光显微镜观察显示，在神经细胞瘤Neuro 2a（N2 a）和朊病毒持续感染N2 a株（ScN 2a）等神经细胞中，PrP定位的线粒体聚集在核周区域，由于PrP在外膜上的堆积，线粒体向细胞膜的顺行运动被完全抑制。核周堆积的线粒体嵴消失，线粒体活性降低。令人惊讶的是，PrP依赖的线粒体核周积累特别发生在神经元细胞上，而在上皮HeLa细胞和成纤维细胞COS-7细胞中，即使在PrP的线粒体靶向后也没有观察到核周积累。
In many neurodegenerative diseases, mitochondria are actively involved in the onset and/or progression of diseases because the energy depletion of the neuronal cells directly leads to the dysfunction and degeneration of cells. In the case of prion diseases, mitochondrial involvement has been reported recently and evidence that prion protein (PrP) is localized in mitochondria is increasing. Despite these findings, the precise molecular mechanism by which PrP targets mitochondria remains unclear. PrP is a secretory protein and does not have a pre-sequence that targets the mitochondria, therefore, we thought that there was a covert signal in the amino acid sequence of PrP. To find the sequence, we constructed various GFP-fused PrP-truncations and colocalization with mitochondria was verified by live-cell imaging. Consequently, we found that 18 amino acids, PrP (122–139), are indispensable for the mitochondrial targeting of PrP. In addition, fluorescent microscopy observation revealed that PrP-localized mitochondria were accumulated at the perinuclear region in neuronal cells such as mouse neuroblastoma Neuro2a (N2a) and prion persistent infection N2a strain (ScN2a), anterograde movement of the mitochondria toward the cell membrane was completely inhibited because of the stacking of PrP on the outer membrane. The cristae formation of perinuclear accumulated mitochondria was disappeared indicating the reduced mitochondrial activity. Surprisingly, PrP-dependent mitochondrial perinuclear accumulation was specifically occurred on neuronal cells, whereas in epithelial HeLa cells and fibroblast COS-7 cells, no perinuclear accumulation observed even after the mitochondrial targeting of PrP.