Proteome Dynamics, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Str. 10, 13125 Berlin, Germany.
Bioinformatics Platform, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Str. 10, 13125 Berlin, Germany.
Cell. 2018 Sep 20;175(1):239-253.e17. doi: 10.1016/j.cell.2018.08.019. Epub 2018 Sep 6.
Many disease-causing missense mutations affect intrinsically disordered regions (IDRs) of proteins, but the molecular mechanism of their pathogenicity is enigmatic. Here, we employ a peptide-based proteomic screen to investigate the impact of mutations in IDRs on protein-protein interactions. We find that mutations in disordered cytosolic regions of three transmembrane proteins (GLUT1, ITPR1, and CACNA1H) lead to an increased clathrin binding. All three mutations create dileucine motifs known to mediate clathrin-dependent trafficking. Follow-up experiments on GLUT1 (SLC2A1), the glucose transporter causative of GLUT1 deficiency syndrome, revealed that the mutated protein mislocalizes to intracellular compartments. Mutant GLUT1 interacts with adaptor proteins (APs) in vitro, and knocking down AP-2 reverts the cellular mislocalization and restores glucose transport. A systematic analysis of other known disease-causing variants revealed a significant and specific overrepresentation of gained dileucine motifs in structurally disordered cytosolic domains of transmembrane proteins. Thus, several mutations in disordered regions appear to cause "dileucineopathies."
许多致病的错义突变影响蛋白质的无规则区域（IDR），但其致病的分子机制尚不清楚。在这里，我们采用基于肽的蛋白质组学筛选来研究 IDR 中突变对蛋白质-蛋白质相互作用的影响。我们发现，三种跨膜蛋白（GLUT1、ITPR1 和 CACNA1H）无规则胞质区域的突变导致网格蛋白结合增加。所有三种突变都产生了介导网格蛋白依赖性运输的二亮氨酸基序。对葡萄糖转运蛋白 GLUT1（SLC2A1）的后续实验，即导致 GLUT1 缺乏综合征的葡萄糖转运蛋白，表明突变蛋白错误定位到细胞内隔室。突变 GLUT1 在体外与衔接蛋白（AP）相互作用，敲低 AP-2 可恢复细胞内定位并恢复葡萄糖转运。对其他已知致病变体的系统分析表明，在跨膜蛋白的结构无序胞质结构域中，获得的二亮氨酸基序明显且特异性过表达。因此，无序区域的几种突变似乎导致了“二亮氨酸病”。
