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:7939721). In addition to its role in translation initiation, also acts as a regulator of translation and stability in the cytoplasm (PubMed:8558852). Component of the CYFIP1-EIF4E-FMR1 complex which binds to the mRNA cap and mediates translational repression: in the complex, EIF4E mediates the binding to the mRNA cap. Component of a multiprotein complex that sequesters and represses translation of proneurogenic factors during neurogenesis (By similarity). In P-bodies, component of a complex that mediates the storage of translationally inactive mRNAs in the cytoplasm and prevents their degradation (By similarity). May play an important role in spermatogenesis through translational regulation of stage-specific mRNAs during germ cell development (PubMed:8558852). eIF4F is a multi-subunit complex, the composition of which varies with external and internal environmental conditions (By similarity). It is composed of at least EIF4A, EIF4E and EIF4G1/EIF4G3. EIF4E is also known to interact with other partners (By similarity). Interacts with EIF4ENIF1/4E-T; promotes recruitment to P-bodies and import into the nucleus. Hypophosphorylated EIF4EBP1, EIF4EBP2 and EIF4EBP3 compete with EIF4G1/EIF4G3 to interact with EIF4E; insulin stimulated MAP-kinase (MAPK1 and MAPK3) phosphorylation of EIF4EBP1 causes dissociation of the complex allowing EIF4G1/EIF4G3 to bind and consequent initiation of translation. Interacts mutually exclusive with EIF4A1 or EIF4A2 (PubMed:7939721). Interacts with NGDN and PIWIL2. Component of the CYFIP1-EIF4E-FMR1 complex composed of CYFIP, EIF4E and FMR1. Interacts directly with CYFIP1. Interacts with CLOCK (By similarity). Binds to MKNK2 in nucleus. Interacts with LIMD1, WTIP and AJUBA. Interacts with APOBEC3G in an RNA-dependent manner. Interacts with LARP1. Interacts with METTL3. Interacts with RBM24; this interaction prevents EIF4E from binding to p53/TP53 mRNA and inhibits the assembly of translation initiation complex. Interacts with DDX3X; interaction is direct and in an RNA-independent manner; this interaction enhances EIF4E cap-binding ability and is required for the repression of cap-dependent translation and the increase of IRES-mediated translation. DDX3X competes with EIF4G1 for interaction with EIF4E (By similarity). Interacts with BTG4 and CNOT7 (By similarity). Interaction with EIF4ENIF1/4E-T is required for localization to processing bodies (P-bodies). Imported in the nucleus via interaction with EIF4ENIF1/4E-T via a piggy-back mechanism. Very high levels in post-meiotic testicular germ cells of rats of reproductive age. Phosphorylation increases the ability of the protein to bind to mRNA caps and to form the eIF4F complex. Belongs to the eukaryotic initiation factor 4E family.