Recognizes and binds the 7-methylguanosine-containing mRNA cap during an early step in the initiation of protein synthesis and facilitates ribosome binding by inducing the unwinding of the mRNAs secondary structures. All 5 eIF4E proteins bind monomethyl cap structures. Only ife-1, ife-2 and ife-5 bind trimethyl cap structures which result from trans-splicing. Translation of trimethyl cap structure mRNAs may be regulated by intracellular redox state; disulfide bonds change the width and depth of the cap-binding cavity determining selectivity to mRNA caps. eIF4F is a multi-subunit complex, the composition of which varies with external and internal environmental conditions. It is composed of at least eIF4A, eIF4E and eIF4G. eIF4E is also known to interact with other partners. Enriched in somatic cells. Completely dispensible; null mutations have no effect on worm. Belongs to the eukaryotic initiation factor 4E family.