National Institutes of Health/Office of the Director
OD021741
米国
National Institutes of Health/Office of the Director
OD026881
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
GM129541
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
GM136321
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
GM137463
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
GM140847
米国
引用
ジャーナル: Sci Adv / 年: 2023 タイトル: Dodecamer assembly of a metazoan AAA chaperone couples substrate extraction to refolding. 著者: Arpit Gupta / Alfred M Lentzsch / Alex Siegel / Zanlin Yu / Un Seng Chio / Yifan Cheng / Shu-Ou Shan / 要旨: Ring-forming AAA chaperones solubilize protein aggregates and protect organisms from proteostatic stress. In metazoans, the AAA chaperone Skd3 in the mitochondrial intermembrane space (IMS) is ...Ring-forming AAA chaperones solubilize protein aggregates and protect organisms from proteostatic stress. In metazoans, the AAA chaperone Skd3 in the mitochondrial intermembrane space (IMS) is critical for human health and efficiently refolds aggregated proteins, but its underlying mechanism is poorly understood. Here, we show that Skd3 harbors both disaggregase and protein refolding activities enabled by distinct assembly states. High-resolution structures of Skd3 hexamers in distinct conformations capture ratchet-like motions that mediate substrate extraction. Unlike previously described disaggregases, Skd3 hexamers further assemble into dodecameric cages in which solubilized substrate proteins can attain near-native states. Skd3 mutants defective in dodecamer assembly retain disaggregase activity but are impaired in client refolding, linking the disaggregase and refolding activities to the hexameric and dodecameric states of Skd3, respectively. We suggest that Skd3 is a combined disaggregase and foldase, and this property is particularly suited to meet the complex proteostatic demands in the mitochondrial IMS.