Eukaryotic translation initiation factor 4E binding protein (EIF4EBP)
This family consists of several eukaryotic translation initiation factor 4E binding proteins (EIF4EBP1,2 and 3). Translation initiation in eukaryotes is mediated by the cap structure (m7GpppN, where N is any nucleotide) present at the 5' end of all cellular mRNAs, except organellar. The cap is recognized by eukaryotic initiation factor 4F (eIF4F), which consists of three polypeptides, including eIF4E, the cap-binding protein subunit. The interaction of the cap with eIF4E facilitates the binding of the ribosome to the mRNA. eIF4E activity is regulated in part by translational repressors, 4E-BP1, 4E-BP2 and 4E-BP3 which bind to it and prevent its assembly into eIF4F.