SYVN1, NEDD8, and FBXO2 Proteins Regulate F508 Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Ubiquitin-mediated Proteasomal Degradation
SYVN1, NEDD8, and FBXO2 Proteins Regulate F508 Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Ubiquitin-mediated Proteasomal Degradation
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DOI：
10.1074/jbc.m116.754283
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发表时间：
2016-12-02
影响因子：
4.8
通讯作者：
McCray, Paul B., Jr.
中科院分区：
文献类型：
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作者：
Ramachandran, Shyam;Osterhaus, Samantha R.;McCray, Paul B., Jr.
我们之前报道过，将针对 SIN3A 的 microRNA-138 模拟物或 siRNA 递送至培养的囊性纤维化 (F508/F508) 气道上皮，部分恢复了 F508 囊性纤维化跨膜电导调节剂 (CFTR) 介导的 cAMP 刺激的 Cl 电导。我们假设剖析这个 microRNA-138/SIN3A 调节的基因网络将鉴定出有助于挽救 F508-CFTR 功能的单个蛋白质。在网络中的基因中，我们使用功能性 CFTR 成熟和极化气道上皮中的电解质转运测定来严格验证候选基因。我们发现，在人囊性纤维化气道上皮原代培养物中，泛素连接酶 SYVN1、泛素/蛋白酶体系统调节剂 NEDD8 或 F-box 蛋白 FBXO2 的消耗部分恢复了 F508-CFTR 介导的 Cl-转运。此外，SYVN1、NEDD8 或 FBXO2 的敲低与校正化合物 18 组合进一步增强了对 F508-CFTR 介导的 Cl-电导的拯救。这项研究提供了 CFTR 生物合成途径的新知识。这表明 SYVN1 和 FBXO2 代表两种不同的多蛋白复合物，可能降解气道上皮中的 F508-CFTR，并确定 NEDD8 在调节 F508-CFTR 泛素化中的新作用。
We previously reported that delivery of a microRNA-138 mimic or siRNA against SIN3A to cultured cystic fibrosis (F508/F508) airway epithelia partially restored F508-cystic fibrosis transmembrane conductance regulator (CFTR)-mediated cAMP-stimulated Cl- conductance. We hypothesized that dissecting this microRNA-138/SIN3A-regulated gene network would identify individual proteins contributing to the rescue of F508-CFTR function. Among the genes in the network, we rigorously validated candidates using functional CFTR maturation and electrolyte transport assays in polarized airway epithelia. We found that depletion of the ubiquitin ligase SYVN1, the ubiquitin/proteasome system regulator NEDD8, or the F-box protein FBXO2 partially restored F508-CFTR-mediated Cl- transport in primary cultures of human cystic fibrosis airway epithelia. Moreover, knockdown of SYVN1, NEDD8, or FBXO2 in combination with corrector compound 18 further potentiated rescue of F508-CFTR-mediated Cl- conductance. This study provides new knowledge of the CFTR biosynthetic pathway. It suggests that SYVN1 and FBXO2 represent two distinct multiprotein complexes that may degrade F508-CFTR in airway epithelia and identifies a new role for NEDD8 in regulating F508-CFTR ubiquitination.