Uncovering Protein Interactions and Membrane Phase Preferences that alter the Plasma Membrane trafficking of Peripheral Myelin Protein 22

项目总结：作为一名独立研究人员，我职业生涯的一个主要目标是了解 膜蛋白在内质网(ER)拥挤的环境中折叠。对这一保真度的破坏 这一过程导致了许多人类疾病，包括阿尔茨海默氏症、帕金森氏症和夏科-玛丽-图斯病 (CMTD)。通过更好地了解这一过程，我希望最终能找到新的治疗策略。 患有这些疾病的患者。CMTD是最常见的周围神经系统(PNS)和 每2500人中就有1人患有此病。超过80%的患有这种疾病的患者都有编码蛋白质的突变。 PMP22基因。PMP22是一种Tetraspan整合膜蛋白，高表达于细胞的质膜。 三叉神经节的髓鞘雪旺细胞。CMTD患者PMP22基因剂量不当导致过多或 雪旺细胞PM的PMP22含量太低。PM时PMP22含量的改变被认为是导致髓鞘 在这些患者中观察到的异常。目前还没有治疗CMTD的方法。PMP22在ER中折叠 监督ER质量控制(QC)体系。该系统既可以帮助PMP22折叠，也可以调解 最终决定是将PMP22传输到PM，还是将蛋白质保留在ER中并最终达到目标 它是为了降级。这项建议的目标是了解调解这一决策过程的因素。上一首 结果表明，野生型(WT)PMP22和PMP22突变体在ER QC中具有不同的蛋白质相互作用 导致不同PM表达的系统。初步数据显示，内质网中蛋白质表达的选择性调节 可以改变PMP22及其疾病突变体的细胞表面转运。此外，PMP22与胆固醇有关 颗粒膜富含膜结构域PNS的另一种膜蛋白P0已被证明与 内质网中的胆固醇是细胞表面运输所必需的。PMP22-/-小鼠来源的雪旺细胞显示 与WT雪旺细胞相比，迁移和黏附能力降低，PM胆固醇含量更低。这 提示PMP22与富含胆固醇结构域的结合对雪旺细胞的功能具有重要意义。这是我的 假设PMP22细胞表面运输可以通过改变其在细胞内的蛋白质相互作用网络来调节 并通过改变其与富含胆固醇的膜域的结合能力。为了解决这一假设，我 威尔：(1)发现内质网中PMP22相互作用体的突变特异性变化，该变化调节其细胞表面运输 以及(2)检查导致PMP22与富含胆固醇的膜结构域相关的因素并评估其影响 关于PMP22交易的胆固醇协会。这项提议的结果将揭示新的蛋白质相互作用和 影响PMP22转运和胆固醇关联的因素。这些信息将为科学家开辟新的途径 试图为患有慢性MTD的患者开发治疗方法。

PROJECT SUMMARY: A major goal of my career as an independent researcher is to understand how integral membrane proteins fold in the crowded environment of the endoplasmic reticulum (ER). Disruptions in the fidelity of this process lead to a number of human diseases including Alzheimer’s, Parkinson’s and Charcot-Marie-Tooth Disease (CMTD). By better understanding this process, I hope to eventually identify novel therapeutic strategies for treating patients afflicted with these diseases. CMTD is the most common neuropathy of the peripheral nervous system (PNS) and afflicts 1 in 2,500 individuals. Over 80% of patients afflicted with this disease have a mutation in the protein encoding PMP22 gene. PMP22 is a tetraspan integral membrane protein that is highly expressed at the plasma membrane (PM) of myelinating Schwann cells of the PNS. Improper gene dosage of PMP22 in CMTD patients results in either too much or too little PMP22 at the PM of Schwann cells. The altered amount of PMP22 at the PM is believed to cause the myelin abnormalities observed in these patients. There are currently no treatments for CMTD. PMP22 folds in the ER under the surveillance of the ER quality control (QC) system. This system both helps PMP22 to fold as well as mediates the ultimate decision whether to traffic PMP22 forward towards the PM or to retain the protein in the ER and ultimately target it for degradation. The goals of this proposal are to understand the factors that mediate this decision process. Previous results show that wild type (WT) PMP22 and PMP22 disease mutants have different protein interactions in the ER QC system leading to varying PM expression. Preliminary data shows that selective modulation of protein expression in ER can alter the cell surface trafficking of PMP22 and its disease mutants. Additionally, PMP22 associates with cholesterol rich membrane domains at the PM. It has been shown for another membrane protein of the PNS, P0, that association with cholesterol in the ER is necessary for cell surface trafficking. Schwann cells derived from PMP22 -/- mice show decreased migration and adhesion capabilities and lower PM cholesterol content compared to WT Schwann cells. This indicates that PMP22 association with cholesterol rich domains is important for Schwann cell function. It is my hypothesis that PMP22 cell surface trafficking can be modulated by both changing its protein interaction network in the ER and through altering its ability to associate with cholesterol rich membrane domains. To address this hypothesis, I will: (1) uncover mutation specific changes to the PMP22 interactome in the ER that modulate its cell surface trafficking and (2) examine the factors that cause PMP22 to associate with cholesterol rich membrane domains and assess the effects of cholesterol association on PMP22 trafficking. The results from this proposal will uncover novel protein interactions and factors that affect PMP22 trafficking and cholesterol association. This information will open novel avenues for scientists attempting to develop therapeutics for patients who suffer from CMTD.