Department of Cell Biology and Physiology, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8228, St. Louis, MO, 63110, USA.
Washington University Center for Cellular Imaging (WUCCI), Washington University School of Medicine, St. Louis, MO, USA.
Nat Commun. 2022 Aug 5;13(1):4570. doi: 10.1038/s41467-022-32318-9.
Molecular chaperones, or heat shock proteins (HSPs), protect against the toxic misfolding and aggregation of proteins. As such, mutations or deficiencies within the chaperone network can lead to disease. Dominant mutations within DNAJB6 (Hsp40)-an Hsp70 co-chaperone-lead to a protein aggregation-linked myopathy termed Limb-Girdle Muscular Dystrophy Type D1 (LGMDD1). Here, we used the yeast prion model client in conjunction with in vitro chaperone activity assays to gain mechanistic insights into the molecular basis of LGMDD1. Here, we show how mutations analogous to those found in LGMDD1 affect Sis1 (a functional homolog of human DNAJB6) function by altering the structure of client protein aggregates, interfering with the Hsp70 ATPase cycle, dimerization and substrate processing; poisoning the function of wild-type protein. These results uncover the mechanisms through which LGMDD1-associated mutations alter chaperone activity, and provide insights relevant to potential therapeutic interventions.
分子伴侣，或热休克蛋白（HSPs），可防止蛋白质的毒性错误折叠和聚集。因此，伴侣网络中的突变或缺陷可能导致疾病。DNAJB6（Hsp40）-Hsp70 共伴侣中的显性突变导致一种称为肢带型肌营养不良症 1 型（LGMDD1）的蛋白聚集相关肌病。在这里，我们使用酵母朊病毒模型客户与体外伴侣活性测定相结合，深入了解 LGMDD1 的分子基础。在这里，我们展示了类似于在 LGMDD1 中发现的突变如何通过改变客户蛋白聚集体的结构、干扰 Hsp70 ATP 酶循环、二聚化和底物处理来影响 Sis1（人类 DNAJB6 的功能同源物）的功能；毒害野生型蛋白的功能。这些结果揭示了与 LGMDD1 相关的突变改变伴侣活性的机制，并为潜在的治疗干预提供了相关见解。
