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. Ife-3 is essential for viability. Component of the pid-1 and tost-1 variants of the PETISCO complexes, which have roles in the biogenesis of a class of 21 nucleotide PIWI-interacting RNAs (piRNAs) that possess a uracil residue at the 5'-end (also called 21U-RNAs) and embryogenesis, respectively (PubMed:31147388, PubMed:31216475). Within the pid-1 variant of the PETISCO complex binds to capped 21U-RNA precursor molecules, possibly playing a role in the processing of the 5' end of the molecules to promote binding of other complex components such as pid-3 (PubMed:31147388). However, it is not essential for the biogenesis of 21U-RNAs by itself (PubMed:31147388). Within the tost-1 variant of the PETISCO complex binds to splice leader SL1 RNA fragments to possibly play a role in their processing (PubMed:31147388). 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. Interacts with mxt (PubMed:26294658). Component of the pid-1 variant of the PETISCO complex (also called the pid-3, erh-2, tofu-6, and ife-3 small RNA complex) containing at least pid-1, tofu-6, ife-3, pid-3, and erh-2, which is required for the biogenesis of a class of 21 nucleotide PIWI-interacting RNAs (piRNAs) that possess a uracil residue at the 5'-end (also called 21U-RNAs) (PubMed:31147388, PubMed:31216475). Component of the tost-1 variant of the PETISCO complex (also called the pid-3, erh-2, tofu-6, and ife-3 small RNA complex) containing at least tost-1, tofu-6, ife-3, pid-3, and erh-2, which plays an essential role in embryogenesis (PubMed:31147388, PubMed:31216475). Within the pid-1 and tost-1 variants of the PETISCO complexes interacts with tofu-6 (via C-terminus) (PubMed:31216475, PubMed:31147388). In contrast to the pid-1 variant of the PETISCO complex, the tost-1 variant of the PETISCO complex plays a minor role in the biogenesis of 21U-RNAs (PubMed:31147388). Localizes to cytoplasmic granules in early embryos (PubMed:31147388). Localizes to puncta in the perinuclear region in the germline syncytium (PubMed:31216475, PubMed:31147388). Highly expressed in the germline (at protein level). Expressed from early embryogenesis (at protein level). RNAi-mediated knockdown results in maternal effect lethal (Mel phenotype) and masculinization of the germline (Mog phenotype) phenotypes (PubMed:31147388). RNAi-mediated knockdown results in defective activity of the PIWI-interacting RNA (piRNA) silencing pathway (PubMed:31147388). Inactivation of ife-3 results in 100% embryonic lethality. Belongs to the eukaryotic initiation factor 4E family.