Involved in T-cell adhesion and p53/TP53-dependent induction of apoptosis. Does not bind RNA. As component of the WAVE1 complex, required for BDNF-NTRK2 endocytic trafficking and signaling from early endosomes (By similarity). {ECO:0000250|UniProtKB:Q5SQX6, ECO:0000269|PubMed:10449408, ECO:0000269|PubMed:15048733, ECO:0000269|PubMed:17245118}. This is the function of CYFIP2 (cytoplasmic FMR1 interacting protein 2, Ensembl gene identifier ENSG00000055163).