N-terminal nesprin-2 variants regulate β-catenin signalling.
N-terminal nesprin-2 variants regulate β-catenin signalling.
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DOI：
10.1016/j.yexcr.2016.06.008
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发表时间：
2016-07-15
影响因子：
3.7
通讯作者：
Warren DT
中科院分区：
文献类型：
--
作者：
Zhang Q;Minaisah RM;Ferraro E;Li C;Porter LJ;Zhou C;Gao F;Zhang J;Rajgor D;Autore F;Shanahan CM;Warren DT
生化信号通路的空间区室化对于细胞功能是必不可少的。Nesprin是一个多异构体的蛋白质家族，已成为信号传导支架，在这里，我们研究了新的Nesprin-2 N-末端变体的定位和功能。我们发现，这些nesprin-2变体显示细胞特异性分布，并驻留在细胞质和细胞核。免疫荧光显微镜显示，nesprin-2 N-末端变体与β-catenin共定位在U2 OS细胞的细胞-细胞连接处。钙开关测定表明，nesprin-2和β-连环蛋白在低钙条件下从细胞-细胞连接中丢失，而NE处的emerin定位保持不变，此外，nesprin-2的N-末端片段足以用于细胞-细胞连接定位并与β-连环蛋白相互作用。使用siRNA耗竭破坏这些N-末端nesprin-2变体导致β-连环蛋白从细胞-细胞连接处丢失、活性β-连环蛋白的核积累和增强的β-连环蛋白转录活性。重要的是，我们发现U2 OS细胞缺乏nesprin-2巨人，这表明N-末端nesprin-2变体独立于NE调节β-连环蛋白信号传导。总之，这些数据将N-末端nesprin-2变体鉴定为β-连环蛋白信号传导的新型调节剂，其将β-连环蛋白拴系到细胞-细胞接触以抑制β-连环蛋白转录活性。N-末端nesprin-2变体显示细胞特异性表达模式。nesprin-2的N-末端血影蛋白重复序列与β-连环蛋白相互作用。N-末端nesprin-2变体在细胞-细胞连接处支架β-连环蛋白。Nesprin-2变体在β-连环蛋白信号传导中发挥多种作用。
The spatial compartmentalisation of biochemical signalling pathways is essential for cell function. Nesprins are a multi-isomeric family of proteins that have emerged as signalling scaffolds, herein, we investigate the localisation and function of novel nesprin-2 N-terminal variants. We show that these nesprin-2 variants display cell specific distribution and reside in both the cytoplasm and nucleus. Immunofluorescence microscopy revealed that nesprin-2 N-terminal variants colocalised with β-catenin at cell-cell junctions in U2OS cells. Calcium switch assays demonstrated that nesprin-2 and β-catenin are lost from cell-cell junctions in low calcium conditions whereas emerin localisation at the NE remained unaltered, furthermore, an N-terminal fragment of nesprin-2 was sufficient for cell-cell junction localisation and interacted with β-catenin. Disruption of these N-terminal nesprin-2 variants, using siRNA depletion resulted in loss of β-catenin from cell-cell junctions, nuclear accumulation of active β-catenin and augmented β-catenin transcriptional activity. Importantly, we show that U2OS cells lack nesprin-2 giant, suggesting that the N-terminal nesprin-2 variants regulate β-catenin signalling independently of the NE. Together, these data identify N-terminal nesprin-2 variants as novel regulators of β-catenin signalling that tether β-catenin to cell-cell contacts to inhibit β-catenin transcriptional activity. N-terminal nesprin-2 variants display cell specific expression patterns. N-terminal spectrin repeats of nesprin-2 interact with β-catenin. N-terminal nesprin-2 variants scaffold β-catenin at cell-cell junctions.. Nesprin-2 variants play multiple roles in β-catenin signalling.