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Functional characterization of the putative lysosomal transporter protein Major facilitator superfamily domain containing 1 (Mfsd1) and its role in sinusoidal obstruction syndrome

假定的溶酶体转运蛋白主要促进子超家族结构域 1 (Mfsd1) 的功能特征及其在血窦阻塞综合征中的作用

基本信息

批准号：
315767030
负责人：
Professor Dr. Markus Damme
金额：
--
依托单位：
Biochemisches Institut
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2016
资助国家：
德国
起止时间：
2015-12-31 至 2020-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/315767030?language=en
关键词：
Functional characterization putative lysosomal transporter

项目摘要

Lysosomes are membrane bound organelles which mediate the degradation of most classes of macromolecules from intracellular or extracellular sources by a concerted action of acid hydrolases. Upon enzymatic degradation of these macromolecules to low molecular weight monomers like amino acids or monosaccharides, the latter become exported from the lysosomal lumen to the cytosol for metabolic reuse by specific transmembrane proteins, so called exporter proteins. Even though lysosomal transporters for a few metabolites are known, the exporter proteins for the great majority including most amino acids and monosaccharides are currently unidentified. Some lysosomal amino acid exporters were shown to play a pivotal role in mechanistic Target of Rapamycin complex (mTORC1)-mediated nutrient signalling at the lysosomal membrane. The ultimate goal of this application is to decipher the function and the substrate(s) of a lysosomal membrane protein from the solute carrier superfamily, called Mfsd1. The protein is assumed to be a transporter for small solutes and was shown in our preliminary experiments to localize to lysosomes, but its substrate(s) is (are) unknown so far. We envisage deciphering its physiological role and transporting function by characterizing the protein in detail, generating loss and gain of function cell lines and analyse an established Mfsd1-knockout mouse model in detail. A possible contribution of Mfsd1 in mTORC1-mediated nutrient-sensing at the lysosomal membrane should also be evaluated. Our preliminary analyses of Mfsd1-knockout mice revealed an early liver phenotype characterised by sinusoidal obstruction and liver sinusoidal endothelial cell death, reflecting the situation in a human hepatic disease called sinusoidal obstruction syndrome. The role of Mfsd1 in the pathogenesis of sinusoidal obstruction syndrome should therefore be investigated. Furthermore the interaction of Mfsd1 with another lysosomal membrane protein called Glmp, will be examined since our preliminary data point to a direct interaction of both proteins and knockout mice of both proteins have a strikingly similar phenotype. In summary, our findings will significantly gain deeper insight into the understanding of transporter functions at the lysosomal membrane. We will identify the metabolites which are transported by Mfsd1 and will determine the physiological function of the protein in knockout mice and particularly in sinusoidal obstruction syndrome.

溶酶体是一种膜结合细胞器，通过酸性水解酶的协同作用，调节细胞内或细胞外来源的大多数大分子的降解。当这些大分子被酶降解成氨基酸或单糖等低分子单体时，后者从溶酶体腔输出到细胞质中，由特定的跨膜蛋白代谢重复使用，即所谓的出口蛋白。尽管已知少数代谢物的溶酶体转运蛋白，但包括大多数氨基酸和单糖在内的绝大多数转运蛋白的转运蛋白目前尚不清楚。一些溶酶体氨基酸输出体在雷帕霉素复合体机械靶标(MTORC1)介导的溶酶体膜营养信号中起着关键作用。本申请的最终目标是破译溶酶体膜蛋白的功能和底物(S)，该蛋白来自溶质载体超家族，称为Mfsd1。该蛋白被认为是小分子溶质的转运蛋白，并在我们的初步实验中被证明定位于溶酶体，但其底物(S)迄今尚不清楚。我们设想通过详细描述该蛋白的特性、产生功能细胞系的损失和获得来破译其生理作用和运输功能，并详细分析已建立的Mfsd1基因敲除小鼠模型。Mfsd1在mTORC1介导的溶酶体膜营养传感中的可能贡献也应该被评估。我们对Mfsd1基因敲除小鼠的初步分析揭示了以肝窦梗阻和肝窦内皮细胞死亡为特征的早期肝脏表型，反映了一种名为正弦梗阻综合征的人类肝病的情况。因此，应研究Mfsd1在肝窦阻塞综合征发病机制中的作用。此外，Mfsd1与另一种名为GlMP的溶酶体膜蛋白的相互作用将被检测，因为我们的初步数据指出这两种蛋白的直接相互作用，并且两种蛋白的敲除小鼠具有惊人的相似表型。综上所述，我们的发现将大大加深对溶酶体膜转运蛋白功能的理解。我们将鉴定由Mfsd1转运的代谢物，并将确定该蛋白在基因敲除小鼠中的生理功能，特别是在正弦阻塞综合征中。