Oxygen-Sensitive Remodeling of Central Carbon Metabolism by Archaic eIF5B.

The eukaryotic translation initiation factor 5B (eIF5B) is a homolog of IF2, an ancient translation factor that enables initiator methionine-tRNAi (met-tRNAi) loading on prokaryotic ribosomes. While it can be traced back to the last universal common ancestor, eIF5B is curiously dispensable in modern aerobic yeast and mammalian cells. Here, we show that eIF5B is an essential element of the cellular hypoxic cap-dependent protein synthesis machinery.