Molecular mechanism of citrate transporter NaCT and its mutations that cause pediatric epilepsies

柠檬酸转运蛋白NaCT及其突变导致小儿癫痫的分子机制

基本信息

批准号：
9904781
负责人：
DANENG WANG
金额：
$ 48.73万
依托单位：
NEW YORK UNIVERSITY SCHOOL OF MEDICINE
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-05-01 至 2023-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9904781
关键词：
Accounting Affect Agreement Astrocytes Binding Binding Sites Biochemical Biological Assay Biophysics Carrier Proteins Cell membrane Cells Child Citrates Citric Acid Cycle Crystallization Cystic Fibrosis Cystic Fibrosis Transmembrane Conductance Regulator Development Developmental Delay Disorders Dimerization Epilepsy Estrogen receptor positive Genes Glues Homology Modeling Hour Human Life Experience Lipids Mass Spectrum Analysis Methods Molecular Molecular Conformation Molecular Structure Mutate Mutation Neurons Neurotransmitters Patients Pattern Play Process Production Proteins Recovery Research Design Role SLC13A5 deficiency Sampling Seizures Site Sodium Structure Subgroup Succinates System Testing base chemical synthesis childhood epilepsy citrate carrier design dimer early onset effective therapy electron density epileptic encephalopathies monomer mutant overexpression prevent small molecule trafficking

项目摘要

SUMMARY Epileptic encephalopathies are a heterogeneous group of severe seizure disorders accounting for approximately 25% of childhood epilepsies. Mutations in the neuronal citrate transporter SLC13A5/NaCT gene abolish its functional activity, causing early onset epileptic encephalopathy (EOEE). The patients display seizures in the first hours of life, and experience developmental delays. The Na+-driven citrate transporter (NaCT) is located in the plasma membrane of neurons. As an intermediate of the citric acid cycle, citrate is critical for energy production in the cell, and it acts as a precursor for the synthesis of lipids and neurotransmitters. Disruption of this citrate import process is therefore understandably harmful to neurons. According to their cellular expression patterns, mutations causing EOEE have been classified as two types. Whereas Type I (protein located in the ER) reduces protein stability, Type II (protein located in the plasma membrane) directly affects the substrate and sodium binding sites or blocks the conformational changes necessary for transport. Based on a homology model of NaCT built from our crystal structure of the bacterial succinate transporter VcINDY, we postulate how each type of mutation alters the NaCT structure and hinders transport activity. We will characterize the mechanisms and structural changes using a combination of biochemical, biophysical and structural approaches. The results will aid in the design of small molecule potentiators and folding correctors with the potential to help the young patients.

概括癫痫性脑病是一组异质性的严重癫痫疾病，大约为童年时期25％。神经元柠檬酸盐转运蛋白转运蛋白SLC13A5/NACT基因的突变消除了其功能活性，导致早期发作癫痫性脑病（EOEE）。患者在生命的第一小时，并体验发展延迟。 Na+驱动的柠檬酸盐转运蛋白（NACT）位于神经元的质膜。作为柠檬酸循环的中级，柠檬酸盐对于能量至关重要细胞中的产生，它是脂质和神经递质合成的前体。破坏因此，这种柠檬酸盐进口过程对神经元有害。根据其细胞表达导致EOEE的模式，突变已被归类为两种类型。而I型（蛋白质位于 ER）降低了蛋白质稳定性，II型（位于质膜中的蛋白质）直接影响底物和钠结合位点或阻断运输所需的构象变化。基于同源模型通过细菌琥珀酸转运蛋白vcindy的晶体结构建造的NACT，我们假设每个人如何突变的类型会改变NACT结构并阻碍运输活性。我们将表征机制以及结构性变化，结合了生化，生物物理和结构方法。结果将有助于设计小分子电位器和折叠校正器，并有可能帮助年轻人患者。