Cross-talks between metabolic and translational controls during beige adipocyte differentiation [Ribo-seq]
Whether and how regulatory events at the translation stage shape the cellular and metabolic features of thermogenic adipocytes is hardly understood. In this study, we report two hitherto unidentified cross-talk pathways between metabolic and translation regulation in beige adipocytes. By analysing temporal profiles of translation activity and protein level changes during precursor-to-beige differentiation, we found selective translational down-regulation of OXPHOS component-coding mRNAs. The down-regulation restricted to Complexes I, III, IV, and V, is coordinated with enhanced translation of TCA cycle genes, engendering distinct stoichiometry of OXPHOS and TCA cycle components and altering the related metabolic activities in mitochondria of thermogenic adipocytes. Our high-resolution description of ribosome positioning unveiled potentiated ribosome pausing at glutamate codons. The increased stalling is driven by elevated glutamate consumption that diminishes glutamate-charged tRNA during pan-adipocyte differentiation. The ribosome pauses decrease protein synthesis and mRNA stability of glutamate codon-rich genes, such as actin cytoskeleton-associated genes. Overall design: Ribo-seq to measure the translation activity upon beige adipocyte differentiation. Adipocyte precursor cells were isolated from inguinal white adipose tissue, and induction of beige adipocyte differentiation was performed. Non-induced and differentiated samples for 4 or 8 days were used for library preparation. For each condition, triplicates were constructed.