Cross-talks between Metabolic and Translational Controls during Beige Adipocyte Differentiation

Area of Science:

• Cellular and Molecular Biology
• Metabolic Regulation
• Adipocyte Biology

Background:

• The role of translational regulation in thermogenic adipocyte development is largely unknown.
• Understanding these mechanisms is crucial for metabolic health and energy expenditure research.

Purpose of the Study:

• To investigate the interplay between metabolic and translational regulation in beige adipocytes.
• To elucidate how translation control influences cellular and metabolic features during adipogenesis.

Main Methods:

• Analysis of temporal translation activity and protein levels during precursor-to-beige adipocyte differentiation.
• High-resolution ribosome profiling to map ribosome positioning and identify pausing sites.
• Investigation of glutamate metabolism and its impact on tRNA charging and translation.

Main Results:

• Identified selective translational down-regulation of oxidative phosphorylation (OXPHOS) component mRNAs (Complexes I, III, IV, V).
• Observed coordinated enhancement of TCA cycle gene translation, altering mitochondrial stoichiometry and metabolic activity.
• Discovered potentiated ribosome pausing at glutamate codons, linked to altered glutamate metabolism and decreased tRNA charging.
• Demonstrated that ribosome pausing reduces protein synthesis and mRNA stability for glutamate-rich genes, including those involved in actin cytoskeleton organization.

Conclusions:

• Two novel cross-talk pathways between metabolic and translational regulation in beige adipocytes were uncovered.
• Translational control significantly shapes mitochondrial function and cellular architecture in thermogenic adipocytes.
• Ribosome pausing at specific codons, influenced by metabolic shifts, acts as a regulatory mechanism impacting gene expression and cellular processes.