EIF4E and fragile X syndrome: The enhanced mTOR signaling observed in the hippocampus of the Fmr1 KO mouse associates with the increase eukaryotic initiation factor complex F4 (eIF4F) [137] and with the increased phosphorylation of the cap-binding protein eukaryotic initiation factor 4E (eIF4E) [136] to further support the increased protein synthesis observed in FXS.