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.In addition to its role in translation initiation, also acts as a regulator of translation and stability in the cytoplasm.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.In P-bodies, component of a complex that mediates the storage of translationally inactive mRNAs in the cytoplasm and prevents their degradation.May play an important role in spermatogenesis through translational regulation of stage-specific mRNAs during germ cell development.