AKT1 glutarylation regulated by GCDH and SIRT5 suppresses oncogenic signaling

Aberrant AKT1 activation is a hallmark of cancer, yet the molecular mechanisms regulating its activity remain incompletely understood. Here, we report that AKT1 undergoes glutarylation at evolutionarily conserved lysines K179 and K289. Mechanistically, AKT1 glutarylation is regulated by the metabolic enzymes GCDH and DHTKD1, which modulate glutaryl-CoA levels, and reversed by the deglutarylase SIRT5. Glutarylation at K179 disrupts the K179-E198 salt bridge and AKT1-ATP interactions, whereas K289 glutarylation perturbs ATP coordination and reduces PDK1-mediated phosphorylation, collectively inactivating AKT1. Functionally, AKT1 glutarylation inhibits cell proliferation and tumor growth, whereas GCDH promotes these oncogenic functions by suppressing glutarylation. Notably, pharmacological MYC inhibition, which downregulates GCDH and elevates AKT1 glutarylation, synergizes with the AKT inhibitor afuresertib to suppress gastric cancer cell growth, revealing a potential therapeutic vulnerability. These findings link lysine metabolism to AKT-driven cancer progression and suggest therapeutic strategies targeting glutarylation dynamics.