YIF1A activates mTORC1 signaling to promote cellular senescence.

The mechanistic target of rapamycin complex 1 (mTORC1) serves as a central metabolic hub that integrates nutrient signals and orchestrates cellular metabolism to regulate many fundamental cell processes. While mTORC1 activation is known to occur both on lysosomal membranes and at the Golgi apparatus in response to environmental cues, the molecular mechanisms governing its Golgi-associated activation remain poorly understood. In this study, we identified YIF1A as a novel Golgi-localized regulator of growth factor-mediated mTORC1 signaling. Mechanistically, YIF1A interacted with the E3 ubiquitin ligase RNF126 to facilitate K48-linked polyubiquitination of G3BP1/2, thereby promoting mTORC1 activation. Genetic depletion of either YIF1A or RNF126 stabilized G3BP1/2 proteins and significantly impaired mTORC1 activity. Notably, YIF1A knockdown conferred resistance to etoposide- and doxorubicin-induced cellular senescence. The evolutionary conservation of this pathway was demonstrated by extended or shortened lifespan in Caenorhabditis elegans lacking or overexpressing yif-1, the invertebrate ortholog of YIF1A. Our findings not only elucidate a previously unrecognized Golgi-specific regulatory axis for mTORC1 activation but also suggest YIF1A as a potential therapeutic target for modulating aging-related pathologies.