Where to begin? The mechanism of translation initiation codon selection in eukaryotes

Selecting the codon at which to begin translation is a complicated event in an already complicated process. Many protein initiation factors (eIFs) have been implicated in start site selection, but the mechanistic details of their activities have remained obscure until recently. Biochemical and genetic studies of eIFs 1, 1A, 2 and 5 have suggested that the 43S pre-initiation complex exists in two conformations and that the changing interactions of the factors within the 43S pre-initiation complex in response to encountering an AUG codon regulates these conformations and, ultimately, the selection of the start codon.