Folding, Misfolding, and Function of PMP22

PMP22的折叠、错误折叠和功能

基本信息

批准号：
9897595
负责人：
Melanie Diane Ohi
金额：
$ 47.18万
依托单位：
VANDERBILT UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-04-01 至 2022-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9897595
关键词：
Adhesions Affect Alleles Amino Acid Sequence Awareness Axon Biochemical Biological Biophysics Cell physiology Cell surface Cells Charcot-Marie-Tooth Disease DNA Sequence Alteration Data Defect Dependence Development Disease Electron Microscopy Endoplasmic Reticulum Future Health Human Integral Membrane Protein Kinetics Lipid Bilayers Lipids Membrane Proteins Molecular Molecular Chaperones Molecular Conformation Mutation Myelin Neural Conduction PMP22 gene Pathway interactions Patients Peripheral Nervous System Peripheral Nervous System Diseases Play Property Proteins Quality Control Role Schwann Cells Series Structure System Testing Therapeutic Thermodynamics Tissues Trisomy Vesicle Work biophysical properties biophysical techniques cytotoxic dysmyelination experimental study glycosylation human disease insight loss of function mutant novel therapeutics organizational structure protein folding public health relevance reconstitution role model trafficking

项目摘要

DESCRIPTION (provided by applicant): Folding, Misfolding, and Function of PMP22 Peripheral myelin protein 22 (PMP22) is a tetraspan integral membrane protein that is abundant in myelin of the peripheral nervous system (PNS). Genetic mutations that encode changes in the amino acid sequence of PMP22 are one cause of the common human peripheral neuropathy Charcot-Marie-Tooth Disease (CMTD). CMTD mutations promote misfolding, retention, and possible degradation of PMP22 early in the secretory pathway, leading to loss of function. This results in dysmyelination of PNS axons and the onset of CMTD. While clearly important, the function of PMP22 in myelin and Schwann cell physiology is not well understood. We recently quantitated the thermodynamic folding stabilities of a series of CMTD mutant forms of PMP22 and established that there is a roughly linear correlation between the thermodynamic stability of PMP22 and both cell surface trafficking efficiencies and patient nerve conduction velocities. In Aim 1 we will compare and contrast the folding kinetics and other properties of different CMTD mutant forms of PMP22 in order to examine whether the specific defects that trigger PMP22 instability and terminal misfolding in the cell are the same from mutant to mutant or whether different CMTD mutants have distinctly different defects beyond differences in stability. In Aim 2 we will determine how the instability of CMTD mutant forms of PMP22 is sensed by endoplasmic reticulum quality control. The cellular data from this aim will be integrated with the results of the biophysical experiments of Aim 1 to provide a unified biophysical and cell biological understanding of how defects in PMP22 are recognized by ER quality control. In Aim 3 we will determine how purified PMP22 promotes formation of myelin-like assemblies (MLAs) following reconstitution into lipid vesicles. This will explore the hypotheses that the role of PMP22 in MLA formation is closely related to at least one of its native functions and also that at least some CMTD mutants are likely to disrupt MLA formation in a manner that reflects how mutations promote dysmyelination in PNS tissue. While CMTD is a relatively common disorder (1:3000), to the best of our knowledge this is the only project in the world that includes the biophysical characterization of PMP22. Completion of the above aims will significantly advance our understanding of the folding, misfolding, and function of this myeli membrane protein under conditions of both health and disease. Results will provide direct insight into the molecular mechanisms underlying CMTD and may pave the way for future development of anti-CMTD therapeutics.

描述（通过应用程序提供）：PMP22外周髓蛋白蛋白22（PMP22）的折叠，错误折叠和功能是一种四面体整合膜蛋白，在外周神经系统（PNS）的髓磷脂中很丰富。编码PMP22氨基酸序列变化的遗传突变是人类外周神经病charcot-marie-marie-tooth疾病（CMTD）的原因之一。 CMTD突变促进了秘密途径早期的不折叠，保留率和PMP22的可能降解，从而导致功能丧失。这会导致PNS轴突和CMTD发作的肿瘤。虽然显然很重要，但PMP22在髓磷脂和Schwann细胞生理学中的功能尚不清楚。我们最近量化了一系列CMTD突变体形式的PMP22的热力折叠稳定性，并确定PMP22的热力学稳定性与细胞表面运输效率与患者神经传导速度之间存在大致线性相关性。在AIM 1中，我们将比较和对比PMP22的不同CMTD突变体形式的折叠动力学和其他特性，以检查触发PMP22不稳定性和终末错误折叠的特定缺陷是否从突变体到突变体是相同的，还是不同的CMTD突变体在稳定性方面差异明显不同。在AIM 2中，我们将确定如何通过内质网质量控制来感知PMP22的CMTD突变形式的不稳定性。该目标的细胞数据将与AIM 1的生物物理实验的结果集成在一起，以提供统一的生物物理和细胞生物学理解PMP22中的缺陷如何通过ER质量控制识别。在AIM 3中，我们将确定纯化的PMP22如何促进重新构造成脂质蔬菜后的髓磷脂样组件（MLA）。这将探讨以下假设：PMP22在MLA形成中的作用与至少一种天然功能密切相关，并且至少某些CMTD突变体可能以反映突变如何促进PNS组织中的肿瘤层化的方式破坏MLA形成。尽管CMTD是一种相对常见的疾病（1：3000），据我们所知，这是唯一的项目包括PMP22的生物物理表征的世界。在健康和疾病的条件下，上述目标的完成将显着提高我们对这种髓膜蛋白的折叠，错误折叠和功能的理解。结果将直接洞悉CMTD的分子机制，并可能为抗CMTD治疗的未来发展铺平道路。