A glycosylation-driven protein complex assembly governs mRNA homeostasis and ensures protein aggregates clearance in cells and organs

Turnover of mRNA, governed by the dynamic balance between synthesis and degradation rates, is a critical mechanism for fine-tuning gene expression. This regulatory process is essential for maintaining mRNA abundance during key biological events, such as maternal mRNA clearance in the maternal-to-zygotic transition and synaptic plasticity during neuronal development. Despite its importance, the molecular mechanisms underlying mRNA turnover and degradation remain poorly understood. In this study, we identify O-GlcNAcylation as a pivotal regulator of mRNA degradation. Specifically, we demonstrate that O-GlcNAcylation of CNOT2 enhances the assembly of the CCR4-NOT complex and augments its ability to regulate the balance of autophagy-related mRNAs. This balance is crucial for maintaining cellular autophagy levels, thereby safeguarding cells from protein aggregation and ensuring cellular homeostasis. Furthermore, we provide evidence that this regulatory mechanism is indispensable for oocyte maturation and the formation of learning and memory. Our findings highlight the central role of O-GlcNAcylation in mRNA turnover regulation and its broader implications for cellular and organismal physiology. Overall design: TAIL Iso-seq for Cnot2 knockdown HeLa cells as well as control cells.