Formation and persistence of polyglutamine aggregates in mistranslating cells

Jeremy T Lant, Rashmi Kiri, Martin L Duennwald, and Patrick O’Donoghue

Nucleic Acids Research (2021) 49 (20):11883–11899.

The authors demonstrate that a tRNASer variant directs Ser incorporation at Phe codons and leads to increased cytotoxicity and increased need for protein degradation in mammalian cells. Using cellular models of Huntingtin’s Disease (HD) to observe huntingtin protein aggregation kinetics and degradation in cells with compromised translation fidelity, they explore the interaction between mistranslation and poly-glutamine aggregation associated with a deleterious huntingtin allele. They find that mistranslating cells respond by severely inhibiting protein synthesis, leading to a reduced but effective formation of protein aggregates in cellular models of HD. The mistranslating cells are also defective in clearing huntingtin aggregates and resistant to the neuroprotective compound ISRIB. Because this compound shows promise as a treatment for neurodegeneration, the study suggests that an active mistranslating tRNA in a patient’s genetic background may contribute to drug resistance.

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