ERP29: PROMOTING ION CHANNEL BIOGENESIS FROM THE ER LUMEN

ERP29：促进 ER 腔的离子通道生物发生

• 批准号: 10302185
• 负责人: Ronald C Rubenstein
• 金额: $ 39.47万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10302185
• 关键词: ERP29; PROMOTING; ION; CHANNEL; BIOGENESIS

PROJECT SUMMARY/ABSTRACT Cystic Fibrosis (CF) and hypertension are life-shortening diseases of epithelial ion transport. In the CF airway, when the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) is functionally absent, there is a relative and unbalanced increase in the activity of the Epithelial Sodium Channel (ENaC) that leads to Na+ absorption from and depletion of the airway surface liquid. In turn, this impairs mucociliary clearance and predisposes the CF airway to bacterial colonization/infection. ENaC can also play a key role in causing hypertension; abnormally increased function of ENaC in the distal tubule of the nephron leads to increased Na+ retention, increased blood volume and hypertension. The regulation of ENaC activity is therefore key in understanding and developing therapies for these diseases of epithelial ion transport. A critical determinant of ENaC's open probability (Po), and therefore its function, is the proteolytic cleavage of the luminal/extracellular loops of its α and γ subunits; uncleaved channel has Po ~0, while fully cleaved channel has Po ~1. In fact, increased ENaC cleavage is reported in CF airway epithelial cells. Interestingly, ENaC can be delivered to the epithelial surface in either a cleaved or an uncleaved form, but the factor(s) that determine whether or not ENaC undergoes cleavage during biogenesis are not known. We have extensively studied Sodium 4-Phenylbutyrate (4PBA), the prototype small molecule corrector of the aberrant trafficking of the most common CF causing CFTR mutation, ΔF508. Others demonstrated that 4PBA also increases the function of ENaC. We found that ERp29 (Endoplasmic Reticulum Protein of 29 kD), a novel, ubiquitously expressed endoplasmic reticulum (ER) luminal chaperone has increased expression in bronchiolar epithelial cells treated with 4PBA, and that ERp29 promotes the trafficking of both wild type and ΔF508-CFTR. ERp29 was thus the first ER luminal component demonstrated to positively influence CFTR trafficking. We have also recently demonstrated that ERp29 promotes the function of ENaC. Interestingly, our data suggest that ERp29 does this by directing ENaC for cleavage in the Golgi during biogenesis, as depletion of ERp29 decreased ENaC function without altering expression of ENaC at the apical epithelial surface. The hypothesis of this proposal is that interaction of the luminal face of epithelial ion channels, such as CFTR and ENaC, with ERp29 during their biogenesis is required to direct these clients from the ER to the Golgi. This hypothesis will be tested with studies Specifically Aiming: 1) To test if ER-luminal facing mutations of CFTR that cause CF and are predicted to not interact with ERp29 have abnormal maturation. 2) To test the mechanism by which ERp29 directs ENaC to the Golgi during biogenesis. 3) To test the mechanism by which ENaC can bypass cleavage in the Golgi en route to the plasma membrane. These studies will yield key mechanistic insights that will be crucial in designing potential ERp29-directed therapeutic interventions for CFTR- and ENaC-opathies.

项目摘要/摘要 囊性纤维化（CF）和高血压是上皮离子转运的寿命疾病。在CF中 气道，囊性纤维化跨膜电导调节剂（CFTR）在功能上不存在 导致Na+的上皮钠通道（ENAC）活性的相对和不平衡增加 气道表面液体的抽象和部署。反过 易于使用细菌定植/感染的CF气道。 ENAC还可以在造成 高血压;否则，ENAC在肾单位的远端小管中的功能增加会导致Na+增加 保留，血容量增加和高血压。因此，ENAC活动的调节是关键 了解和开发这些上皮离子运输疾病的疗法。 ENAC开放概率（PO）的关键决定者，因此其功能是蛋白水解的裂解 其α和γ亚基的腔/细胞外环；未泄漏的通道具有PO〜0，而完全切割的通道 有po〜1。实际上，在CF气道上皮细胞中报道了ENAC裂解增加。有趣的是，ENAC可以是 以裂解或未裂解的形式递送到上皮表面，但要确定的因子 尚不清楚ENAC是否在生物发生过程中进行裂解。 我们已经进行了广泛研究的4-苯基丁酸钠（4pba），该原型的原型小分子校正器 最常见的CF的异常运输，导致CFTR突变ΔF508。其他人证明了4pba 还增加了ENAC的功能。我们发现ERP29（29 kD的内质网蛋白），一种小说， 普遍表达的内质网（ER）腔内链酮在支气管中的表达增加 用4PBA处理的上皮细胞，ERP29促进了野生型和ΔF508-CFTR的运输。 因此，ERP29是第一个ER腔分量，该成分被证明会积极影响CFTR运输。 我们最近还证明ERP29促进了ENAC的功能。有趣的是，我们的数据 表明ERP29通过指导生物发生过程中的Golgi裂解ENAC来做到这一点，作为耗竭 ERP29降低了ENAC功能，而不会改变顶部上皮表面的ENAC表达。这 该提议的假设是上皮离子通道的腔脸的相互作用，例如CFTR和 ENAC，需要在生物发生过程中使用ERP29才能将这些客户从ER引导到高尔基体。这 假设将通过专门针对的研究对假设进行检验：1）测试ER亮型面对CFTR突变是否是 原因CF，预计不与ERP29相互作用具有异常成熟。 2）通过 ERP29在生物发生过程中将ENAC引导到高尔基体。 3）测试ENAC可以绕过的机制 高尔基体在通往质膜的途径中的裂解。这些研究将产生关键的机理见解 对于设计潜在的ERP29定向治疗干预措施至关重要。

项目成果

Bitter taste receptor agonists regulate epithelial two-pore potassium channels via cAMP signaling.

• DOI: 10.1186/s12931-021-01631-0
• 发表时间: 2021-01-28
• 期刊: Respiratory research
• 影响因子: 5.8
• 作者: Kohanski MA;Brown L;Orr M;Tan LH;Adappa ND;Palmer JN;Rubenstein RC;Cohen NA
• 通讯作者: Cohen NA

Editorial Focus: CFTR-dependent bicarbonate secretion by Calu-3 cells.

• DOI: 10.14814/phy2.13691
• 发表时间: 2018-05
• 期刊: Physiological reports
• 影响因子: 2.5
• 作者: Rubenstein RC

ERp29 as a regulator of Insulin biosynthesis.

ERp29 作为胰岛素生物合成的调节剂。

• DOI: 10.1371/journal.pone.0233502
• 发表时间: 2020
• 期刊: PloS one
• 影响因子: 3.7
• 作者: Viviano,Jeffrey;Brecker,Margaret;Ferrara-Cook,Christine;Suaud,Laurence;Rubenstein,RonaldC
• 通讯作者: Rubenstein,RonaldC

Correction: ERp29 as a regulator of Insulin biosynthesis.

更正：ERp29 作为胰岛素生物合成的调节剂。

• DOI: 10.1371/journal.pone.0238264
• 发表时间: 2020
• 期刊: PloS one
• 影响因子: 3.7
• 作者: Viviano,Jeffrey;Brecker,Margaret;Ferrara-Cook,Christine;Suaud,Laurence;Rubenstein,RonaldC
• 通讯作者: Rubenstein,RonaldC

Safety and efficacy of treatment with lumacaftor in combination with ivacaftor in younger patients with cystic fibrosis.

lumacaftor 与 ivacaftor 联合治疗年轻囊性纤维化患者的安全性和有效性。

• DOI: 10.1080/17476348.2019.1602040
• 发表时间: 2019
• 期刊: Expert review of respiratory medicine
• 影响因子: 3.9
• 作者: Cheng,PiChun;Alexiou,Stamatia;Rubenstein,RonaldC
• 通讯作者: Rubenstein,RonaldC