Cytoplasmic FMR1-interacting protein 1 is a component of the CYFIP1-EIF4E-FMR1 complex which binds to the mRNA cap and mediates translational repression. In the CYFIP1-EIF4E-FMR1 complex this subunit is an adapter between EIF4E and FMR1. CYFIP1 promotes the translation repression activity of FMR1 in brain probably by mediating its association with EIF4E and mRNA. CYFIP1 is involved in formation of membrane ruffles and lamellipodia protrusions and in axon outgrowth. CYFIP1 may act as an invasion suppressor in cancers [taken from the Universal Protein Resource (UniProt) www.uniprot.org/uniprot/ Q7L576].