Department of Clinical Genetics, Shengjing Hospital of China Medical University, Shenyang, China.
Department of Medical Genetics, China Medical University, Shenyang, China.
Biochim Biophys Acta Mol Basis Dis. 2021 Jun 1;1867(6):166128. doi: 10.1016/j.bbadis.2021.166128. Epub 2021 Mar 13.
Neural precursor cell expressed developmentally down-regulated gene 4-like (NEDD4-2) encodes a ubiquitin E3 ligase that is involved in epileptogenesis with mechanisms needing further investigation. We constructed a novel Nedd4-2 mouse model with half level of both Nedd4-2 long and short isoforms in the brain. Nedd4-2 haploinsufficiency caused increased susceptibility and severity of pentylenetetrazole (PTZ)-induced seizures. Of the 3379 proteins identified by the hippocampal proteomic analysis, 55 were considered altered in Nedd4-2 mice compared with wild-type control, among which the inwardly rectifying K channel Kir4.1 was up-regulated by 1.83-fold. Kir4.1 was subsequently confirmed to be less ubiquitinated in response to comprised Nedd4-2 in mouse brains and C6 cells. Kir4.1 associated with Nedd4-2 through the threonine-proline motif in the intracellular domain by target mutagenesis. Adaptor protein 14-3-3 facilitated Nedd4-2-mediated ubiquitination of Kir4.1. Our data consolidate the detailed molecular mechanism of Nedd4-2-mediated Kir4.1 ubiquitination, and provide a possible relationship between increased seizure susceptibility and impaired Kir4.1 ubiquitination in the brain.
神经前体细胞表达发育下调基因 4 样（NEDD4-2）编码一种泛素 E3 连接酶，参与癫痫发生的机制尚需进一步研究。我们构建了一种新型的 Nedd4-2 小鼠模型，其大脑中两种 Nedd4-2 长和短异构体的水平均减半。Nedd4-2 杂合不足导致戊四氮（PTZ）诱导的癫痫发作易感性和严重程度增加。通过海马体蛋白质组分析鉴定的 3379 种蛋白质中，与野生型对照组相比，Nedd4-2 小鼠中有 55 种被认为发生了改变，其中内向整流钾通道 Kir4.1 上调了 1.83 倍。随后通过小鼠大脑和 C6 细胞中的组成型 Nedd4-2 证实 Kir4.1 的泛素化减少。Kir4.1 通过其细胞内结构域中的苏氨酸-脯氨酸基序与 Nedd4-2 相关联，通过靶突变。衔接蛋白 14-3-3 促进了 Nedd4-2 介导的 Kir4.1 泛素化。我们的数据整合了 Nedd4-2 介导的 Kir4.1 泛素化的详细分子机制，并提供了大脑中癫痫易感性增加和 Kir4.1 泛素化受损之间可能存在的关系。
