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. Required for progression through meiotic divisions during spermatogenesis and for the production of viable sperm. It is not required during oogenesis. 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, including pgl-1 (PubMed:11641215). Interacts with ifet-1 (PubMed:19786575). When associated with pgl-1. Enriched in the germline from L3 larvae to adults; regions of the gonad undergoing spermatogenesis. Expressed in germ granules (P granules); when associated with pgl-1. Expressed both maternally and zygotically. Ubiquitous embryonic expression until the 100-200 cell stage then disappears by the 300-400 cell stage. Expressed again in L3 larvae through to adulthood. Defects can cause a delay in spermatogenesis, temperature-sensitive sterility and defective sperm. Belongs to the eukaryotic initiation factor 4E family.