Ubiquitination of ABCE1 by NOT4 in Response to Mitochondrial Damage Links Co-translational Quality Control to PINK1-Directed Mitophagy

Publication date: Available online 31 May 2018
Source:Cell Metabolism
Author(s): Zhihao Wu, Yan Wang, Junghyun Lim, Boxiang Liu, Yanping Li, Rasika Vartak, Trisha Stankiewicz, Stephen Montgomery, Bingwei Lu
Translation of mRNAs is tightly regulated and constantly surveyed for errors. Aberrant translation can trigger co-translational protein and RNA quality control processes, impairments of which cause neurodegeneration by still poorly understood mechanism(s). Here we show that quality control of translation of mitochondrial outer membrane (MOM)-localized mRNA intersects with the turnover of damaged mitochondria, both orchestrated by the mitochondrial kinase PINK1. Mitochondrial damage causes stalled translation of complex-I 30 kDa subunit (C-I30) mRNA on MOM, triggering the recruitment of co-translational quality control factors Pelo, ABCE1, and NOT4 to the ribosome/mRNA-ribonucleoprotein complex. Damage-induced ubiquitination of ABCE1 by NOT4 generates poly-ubiquitin signals that attract autophagy receptors to MOM to initiate mitophagy. In the Drosophila PINK1 model, these factors act synergistically to restore mitophagy and neuromuscular tissue integrity. Thus ribosome-associated co-translational quality control generates an early signal to trigger mitophagy. Our results have broad therapeutic implications for the understanding and treatment of neurodegenerative diseases.

Graphical abstract

Teaser

Removal of damaged mitochondria is essential for maintaining cellular vitality, but the earliest signal that initiates the mitophagy process is not well defined. Wu et al. show that mitochondrial damage causes stalled translation of OXPHOS-related mRNAs on the mitochondrial surface. Co-translational quality control of stalled ribosomes generates ubiquitin-containing signals that trigger mitophagy.


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