Structure, Folding, and Misfolding of PMP22

描述（由申请人提供）：编码外周髓磷脂蛋白22 （PMP22）的基因的遗传显性突变导致其序列中的单个氨基酸改变，导致髓磷脂缺陷，这是常见的人类外周神经病变，即IA型沙科-玛丽-牙病（CMTD）的基础。据认为，CMTD突变导致PMP22在分泌途径的早期错误组装，导致蛋白质功能丧失，并形成潜在的细胞毒性聚集体。该项目的总体目标是阐明cmtd相关突变对这种关键膜蛋白的结构、稳定性和折叠所造成的扰动的分子生物物理性质。我们还试图测试化学伴侣是否可以纠正通常在PMP22的CMTD突变形式中观察到的折叠缺陷。目的1。利用核磁共振光谱分析人类PMP22野生型（WT）和CMTD突变型的结构。目的1将验证PMP22的CMTD突变形式在构象和/或寡聚状态方面与WT蛋白不同的假设。结构信息还将阐明PMP22的结构/功能关系及其在髓磷脂产生和维持中的作用，并将为氨基酸突变如何导致CMTD提供生物物理学见解。确定PMP22的结构也将增加目前人类膜蛋白结构的稀疏画廊。目标2。表征PMP22 WT和CMTD突变型的稳定性和折叠动力学。目的2将验证PMP22的疾病相关突变使该蛋白不稳定的假设。Aim 2还将验证PMP22的疾病相关突变形式比野生型蛋白折叠更慢和/或效率更低的假设。我们还将测试PMP22的CMTD突变形式是否易于聚集。目标3。确定化学伴侣是否可以增加PMP22的CMTD突变形式的细胞表面表达。目标3将测试PMP22类似于其他与涉及蛋白质错误组装的疾病有关的人类膜蛋白的假设，并且已经确定可以使用化学伴侣恢复适当的折叠和运输。

DESCRIPTION (provided by applicant): Genetically dominant mutations in the gene that encodes peripheral myelin protein 22 (PMP22) lead to single amino acid changes in its sequence that result in defective myelin, underlying the common human peripheral neuropathy, Charcot-Marie-Tooth Disease Type IA (CMTD). It is believed that CMTD mutations result in misassembly of PMP22 early in the secretory pathway, resulting in the loss of protein function and also in the formation of potentially cytotoxic aggregates. The overall goal of this project is to elucidate the molecular biophysical nature of the perturbations made by CMTD-associated mutations to the structure, stability and folding of this critical membrane protein. We also seek to test whether chemical chaperones can correct the folding defects normally observed for CMTD mutant forms of PMP22. Aim 1. Characterize the structures of the wild type (WT) and CMTD mutant forms of human PMP22 using NMR spectroscopy. Aim 1 will test the hypothesis that CMTD mutant forms of PMP22 differ from the WT protein in terms of conformation and/or oligomeric state. Structural information will also illuminate PMP22's structure/function relationships and its role in myelin production and maintenance, and will provide biophysical insight into how amino acid mutations result in CMTD. Determination of PMP22's structure will also add to the currently sparse gallery of human membrane protein structures. Aim 2. Characterize the stability and folding kinetics of WT and CMTD mutant forms of PMP22. Aim 2 will test the hypothesis that disease-related mutations of PMP22 destabilize the protein. Aim 2 will also test the hypothesis that disease-related mutant forms of PMP22 fold more slowly and/or inefficiently than the wild type protein. We will also test whether CMTD mutant forms of PMP22 are aggregation-prone. Aim 3. Determine whether chemical chaperones can increase the cell surface expression of CMTD mutant forms of PMP22. Aim 3 will test the hypothesis that PMP22 is akin to other human membrane proteins that are linked to diseases involving protein misassembly and for which it has already been established that proper folding and trafficking can be restored using chemical chaperones. PUBLIC HEALTH RELEVANCE: Studies of the structure, folding, and stability of the human peripheral myelin protein 22 (PMP22) will be undertaken to unravel the molecular basis for Charcot-Marie Tooth Disease, a peripheral neuropathy. Results from this work are expected to contribute to novel therapeutic strategies for this human disease.