Translation initiation is a complex event requiring several proteins, called initiation factors (IFs), which allow i) the formation of the ribosomal pre-initiation complex, ii) the recruitment of the 43S complex to the 5′ end of the mRNA, iii) the scanning of the 5′UTR, and iv) the recognition of the AUG codon and the 5′ cap. Capping at the 5′ end is a key process consisting in the addition of 7-methylguanosine to the 5′UTR, which confers protection to the mRNA against degradation, ultimately promoting nuclear export and translation.33
