Researchers at Massachusetts General Hospital and Harvard Medical School have revealed significant findings regarding the role of protein aggregates in neurodegenerative diseases, including Alzheimer's and Parkinson's. Their study highlights how these aggregates may disrupt critical cellular processes, specifically affecting the processing of transfer RNAs (tRNAs). The study, published in Science, focuses on genetic forms of neurodegeneration linked to GGC trinucleotide repeat expansions. These genetic mutations lead to the production of proteins rich in glycine, creating aggregates that can be detected across various tissues and cell types in affected individuals. However, the diseases predominantly manifest in the central nervous system. The researchers aimed to uncover the mechanisms by which these polyglycine aggregates exert their toxic effects on brain cells. They utilized a combination of biochemical techniques and mass spectrometry to analyze the proteins associated with these aggregates, discovering that they specifically sequester the tRNA ligase complex, essential for tRNA processing. Disruption of tRNA processing due to the aggregation of the tRNA ligase complex was found to lead to misprocessed tRNAs, both in laboratory cultures and in human brain tissues. Notably, experiments with mouse models demonstrated that depletion of the tRNA ligase complex resulted in neurodegeneration and motor coordination issues, mirroring symptoms seen in GGC repeat disorders. The findings underscore a novel connection between protein aggregation and RNA processing defects in neurodegenerative diseases. This research opens potential avenues for therapeutic interventions aimed at mitigating the effects of protein aggregation on tRNA processing. Future research will focus on further elucidating the cellular and molecular impacts of altered tRNA splicing in the brain, with the goal of developing targeted treatments for these debilitating disorders.