Rapid degradation of progressive ankylosis protein (ANKH) in craniometaphyseal dysplasia
Rapid degradation of progressive ankylosis protein (ANKH) in craniometaphyseal dysplasia
复制标题
DOI：
10.1038/s41598-018-34157-5
复制
发表时间：
2018-10-24
影响因子：
4.6
通讯作者：
Chen, I-Ping
中科院分区：
文献类型：
--
作者：
Kanaujiya, Jitendra;Bastow, Edward;Chen, I-Ping
进行性强直蛋白（NP_473368，人类 ANKH）突变会导致颅骨干骺端发育不良（CMD），其特征是颅面骨进行性增厚和长骨干骺端增宽。 CMD 的发病机制在很大程度上仍不清楚，CMD 的治疗仅限于手术干预。我们报道了携带 ANK F377del 突变的敲入小鼠（Ank(KI/KI)）（NM_020332，小鼠 ANK）复制了 CMD 的许多特征。有趣的是，Ank（KO/KO）小鼠中 Ank 基因的消除也会导致几种 CMD 样表型。引起 CMD 的突变导致 ANK/ANKH 蛋白由于快速降解而稳态水平降低。虽然野生型 (wt) ANK 主要与质膜、内质网 (ER)、高尔基体和溶酶体相关，但 CMD 连接的突变型 ANK 异常定位于细胞质中。蛋白酶体降解抑制剂显着恢复了过表达突变型 ANK 的水平，而溶酶体降解抑制剂则更强烈地增加了内源性 CMD 突变型 ANK/ANKH 水平。然而，这些抑制剂不能纠正突变 ANK 的错误定位。在细胞中共表达 wt 和 CMD 突变型 ANK 表明，CMD 突变型 ANK 不会对 wt ANK 表达和定位产生负面影响，反之亦然。总之，我们发现 CMD 突变 ANK/ANKH 蛋白寿命短且在细胞中错误定位，这可能是 CMD 发病机制的一部分。
Mutations in the progressive ankylosis protein (NP_473368, human ANKH) cause craniometaphyseal dysplasia (CMD), characterized by progressive thickening of craniofacial bones and widened metaphyses in long bones. The pathogenesis of CMD remains largely unknown, and treatment for CMD is limited to surgical intervention. We have reported that knock-in mice (Ank(KI/KI)) carrying a F377del mutation in ANK (NM_020332, mouse ANK) replicate many features of CMD. Interestingly, ablation of the Ank gene in Ank(KO/KO) mice also leads to several CMD-like phenotypes. Mutations causing CMD led to decreased steady-state levels of ANK/ANKH protein due to rapid degradation. While wild type (wt) ANK was mostly associated with plasma membranes, endoplasmic reticulum (ER), Golgi apparatus and lysosomes, CMD-linked mutant ANK was aberrantly localized in cytoplasm. Inhibitors of proteasomal degradation significantly restored levels of overexpressed mutant ANK, whereas endogenous CMD-mutant ANK/ANKH levels were more strongly increased by inhibitors of lysosomal degradation. However, these inhibitors do not correct the mislocalization of mutant ANK. Co-expressing wt and CMD-mutant ANK in cells showed that CMD-mutant ANK does not negatively affect wt ANK expression and localization, and vice versa. In conclusion, our finding that CMD mutant ANK/ANKH protein is short-lived and mislocalized in cells may be part of the CMD pathogenesis.