Elongation factor 1A1 regulates metabolic substrate preference in mammalian cells

Area of Science:

• Cell Biology
• Metabolism
• Molecular Biology

Background:

• Eukaryotic elongation factor 1A1 (EEF1A1) is known for protein synthesis but has other cellular roles.
• Previous work linked EEF1A1 to lipotoxicity and liver lipid accumulation.
• This suggests a connection between EEF1A1 and metabolic regulation.

Purpose of the Study:

• To investigate the role of EEF1A1 in regulating metabolic substrate preference.
• To understand how EEF1A1 influences glycolysis and oxidative metabolism.

Main Methods:

• Used EEF1A1-deficient Chinese hamster ovary (2E2) cells and EEF1A1 knockdown in HepG2 cells.
• Employed extracellular flux analysis to assess metabolic phenotypes.
• Utilized RNA-seq, immunoblotting, and enzyme activity assays to analyze gene and protein expression.
• Treated cells with EEF1A inhibitors (didemnin B, plitidepsin).

Main Results:

• EEF1A1 deficiency or inhibition reduced lactate production and glycolytic ATP, favoring oxidative metabolism.
• Increased fatty acid oxidation and neutral lipid content were observed in EEF1A1-deficient cells.
• Hexokinase 2, a key glycolytic enzyme, was significantly downregulated.
• Downregulation of TNFA signaling via NFKB and MYC targets, with reduced nuclear RELB and MYC.

Conclusions:

• EEF1A1 plays a role in regulating metabolic substrate utilization in mammalian cells.
• EEF1A1 deficiency perturbs glycolysis by affecting NFKB- and MYC-mediated gene expression.
• This leads to decreased hexokinase expression and activity, shifting metabolic preference.