Component of the protein complex eIF4F, which is involved in the recognition of the mRNA cap, ATP-dependent unwinding of 5'-terminal secondary structure and recruitment of mRNA to the ribosome (PubMed:17898986). 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 (PubMed:17898986). EIF4F is a multi-subunit complex, the composition of which varies with external and internal environmental conditions (PubMed:17898986). It is composed of at least EIF4A, EIF4E and EIF4G. EIF4E is also known to interact with other partners (PubMed:17898986). In higher plants two isoforms of EIF4F have been identified, named isoform EIF4F and isoform EIF(iso)4F (PubMed:17898986). Isoform EIF4F has subunits p220 and p26, whereas isoform EIF(iso)4F has subunits p82 and p28 (PubMed:17898986). According to the redox status, the Cys-125-Cys-163 disulfide bridge may have a role in regulating protein function by affecting its ability to bind capped mRNA. Belongs to the eukaryotic initiation factor 4E family.