Origins and evolution of the mechanisms regulating translation initiation in eukaryotes

Translation in eukaryotes is a complex process that is closely regulated, mainly at the initiation step. Both universal and lineage-specific mechanisms regulate translation initiation. Considerable progress in our understanding of the regulation of translation has been achieved, but how these regulatory mechanisms evolved remains poorly understood. New discoveries in different fields suggest that the mechanisms that regulate translation emerged at different times during the evolution of eukaryotes, and that some initially evolved independently of the translation apparatus and were later incorporated into it. Overall, the emerging view suggests that 'tinkering' (i.e. co-opting and assembling molecules and regulatory mechanisms from other cellular processes) contributed importantly to the development of the mechanisms that regulate translation initiation during eukaryotic evolution.