关键词: CAT-tailing MISTERMINATE PINK1/Parkin Parkinson’s disease RQC mitochondrial stress neurodegeneration proteostasis ribosome stalling translation termination

Mesh : Animals Codon, Terminator Drosophila Proteins / genetics metabolism Drosophila melanogaster HeLa Cells Humans Mitochondria / genetics metabolism pathology Mitochondrial Diseases / genetics metabolism pathology Mitochondrial Proteins / genetics metabolism Proteostasis Deficiencies / genetics metabolism pathology RNA, Mitochondrial / genetics metabolism

来  源:   DOI:10.1016/j.molcel.2019.06.031   PDF(Sci-hub)   PDF(Pubmed)

Abstract:
Mitochondrial dysfunction and proteostasis failure frequently coexist as hallmarks of neurodegenerative disease. How these pathologies are related is not well understood. Here, we describe a phenomenon termed MISTERMINATE (mitochondrial-stress-induced translational termination impairment and protein carboxyl terminal extension), which mechanistically links mitochondrial dysfunction with proteostasis failure. We show that mitochondrial dysfunction impairs translational termination of nuclear-encoded mitochondrial mRNAs, including complex-I 30kD subunit (C-I30) mRNA, occurring on the mitochondrial surface in Drosophila and mammalian cells. Ribosomes stalled at the normal stop codon continue to add to the C terminus of C-I30 certain amino acids non-coded by mRNA template. C-terminally extended C-I30 is toxic when assembled into C-I and forms aggregates in the cytosol. Enhancing co-translational quality control prevents C-I30 C-terminal extension and rescues mitochondrial and neuromuscular degeneration in a Parkinson\'s disease model. These findings emphasize the importance of efficient translation termination and reveal unexpected link between mitochondrial health and proteome homeostasis mediated by MISTERMINATE.
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