Defective trafficking of nephrin missense mutants rescued by a chemical chaperone
Defective trafficking of nephrin missense mutants rescued by a chemical chaperone
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DOI：
10.1097/01.asn.0000129826.28932.fd
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发表时间：
2004-07-01
影响因子：
13.6
通讯作者：
Tryggvason, K
中科院分区：
文献类型：
--
作者：
Liu, XL;Doné, SC;Tryggvason, K
芬兰型先天性肾病综合征的肾病蛋白基因 (NPHS1) 发生突变。在非芬兰患者中发现的大多数突变都是错义突变。先天性肾病综合征中错义突变最常见的后果是突变蛋白在内质网（ER）中的细胞内转运和保留缺陷，可能是由于错误折叠和不利构象造成的。由于 4-苯基丁酸钠已被证明可作为化学伴侣并纠正几种错误定位或错误折叠的突变质膜蛋白的细胞运输，因此研究了该化合物对芬兰型先天性肾病综合征患者中发现的错义突变体的影响。本研究使用人胚胎肾 293 细胞进行，该细胞稳定表达 ER 中捕获的野生型或错义去氧肾上腺素突变体。免疫荧光显微镜和细胞表面生物素化表明，用 4-苯基丁酸钠处理可以挽救一些从内质网到细胞表面的错义突变体。所有获救的突变体均被发现能够与 Neph1 相互作用。此外，它们的酪氨酸磷酸化是通过与抗去氧肾上腺素抗体聚集而迅速诱导的，这表明被拯救的突变体可能在功能上是完整的。
The nephrin gene (NPHS1) is mutated in congenital nephrotic syndrome of the Finnish type. Most mutations found in non-Finnish patients are missense mutations. The most common consequence of missense mutations in congenital nephrotic syndrome is a defect in intracellular transport and retention of the mutant proteins in the endoplasmic reticulum (ER), possibly as a result of misfolding and unfavored conformation. Because sodium 4-phenylbutyrate has been shown to function as a chemical chaperone and to correct the cellular trafficking of several mislocalized or misfolded mutant plasma membrane proteins, the effects of this compound on the missense mutants identified in patients with congenital nephrotic syndrome of the Finnish type were investigated. This study was performed using human embryonic kidney 293 cells stably expressing wild-type or missense nephrin mutants trapped in the ER. Immunofluorescence microscopy and cell surface biotinylation showed that treatment with sodium 4-phenylbutyrate rescued several of the missense mutants from the ER to the cell surface. All of the rescued mutants were found to be able to interact with Neph1. Furthermore, their tyrosine phosphorylation was rapidly induced by clustering with anti-nephrin antibodies, suggesting that the rescued mutants may be functionally intact.