Hypothesis 3: FMRP inhibits cap-dependant translation. Cap-dependent translation requires eIF4F complex (comosed of eIFG-eIF4F-eIF4E) for translational initiation and are inhibited when 4E-binding proteins (4E-BP) interfer with the complex. FMRP inhibits this type of translation by recruiting and binding cytoplasmic FMRP-interacting protein (CYFIP1) to target mRNAs and subsequently associates with eIF4E, thereby forming a FMRP/CYFIP1/eIF4E complex, blocking the recruitment of the translation initation machinery.