Papadopoulos Chrisovalantis, Kirchner Philipp, Bug Monika, Grum Daniel, Koerver Lisa, Schulze Nina, Poehler Robert, Dressler Alina, Fengler Sven, Arhzaouy Khalid, Lux Vanda, Ehrmann Michael, Weihl Conrad C, Meyer Hemmo
Molecular Biology I, Faculty of Biology, Centre for Medical Biotechnology, University of Duisburg-Essen, Essen, Germany.
Imaging Center Campus Essen, Faculty of Biology, Centre for Medical Biotechnology, University of Duisburg-Essen, Essen, Germany.
EMBO J. 2017 Jan 17;36(2):135-150. doi: 10.15252/embj.201695148. Epub 2016 Oct 17.
Rupture of endosomes and lysosomes is a major cellular stress condition leading to cell death and degeneration. Here, we identified an essential role for the ubiquitin-directed AAA-ATPase, p97, in the clearance of damaged lysosomes by autophagy. Upon damage, p97 translocates to lysosomes and there cooperates with a distinct set of cofactors including UBXD1, PLAA, and the deubiquitinating enzyme YOD1, which we term ELDR components for Endo-Lysosomal Damage Response. Together, they act downstream of K63-linked ubiquitination and p62 recruitment, and selectively remove K48-linked ubiquitin conjugates from a subpopulation of damaged lysosomes to promote autophagosome formation. Lysosomal clearance is also compromised in MEFs harboring a p97 mutation that causes inclusion body myopathy and neurodegeneration, and damaged lysosomes accumulate in affected patient tissue carrying the mutation. Moreover, we show that p97 helps clear late endosomes/lysosomes ruptured by endocytosed tau fibrils. Thus, our data reveal an important mechanism of how p97 maintains lysosomal homeostasis, and implicate the pathway as a modulator of degenerative diseases.
内体和溶酶体破裂是导致细胞死亡和退化的主要细胞应激状态。在此,我们确定了泛素导向的AAA-ATP酶p97在通过自噬清除受损溶酶体中的关键作用。受损时,p97转位至溶酶体,并在那里与一组不同的辅助因子协同作用,包括UBXD1、PLAA和去泛素化酶YOD1,我们将其称为内体-溶酶体损伤反应(Endo-Lysosomal Damage Response,ELDR)组分。它们共同作用于K63连接的泛素化和p62募集的下游,选择性地从受损溶酶体亚群中去除K48连接的泛素缀合物,以促进自噬体形成。在携带导致包涵体肌病和神经退行性变的p97突变的小鼠胚胎成纤维细胞(MEFs)中,溶酶体清除也受到损害,并且受损溶酶体在携带该突变的受影响患者组织中积累。此外,我们表明p97有助于清除被内吞的tau原纤维破裂的晚期内体/溶酶体。因此,我们的数据揭示了p97维持溶酶体稳态的重要机制,并表明该途径是退行性疾病的调节因子。