RNA-binding protein. Interacts with FMR1 (PubMed:7489725, PubMed:8668200, PubMed:11157796). Interacts with FXR1 (PubMed:7489725). Interacts with TDRD3 (PubMed:18664458). Interacts with HABP4 (PubMed:21771594). Interacts with CYFIP2 but not with CYFIP1 (By similarity). (Microbial infection) Interacts with Sindbis virus non-structural protein 3 (via C-terminus); this interaction inhibits the formation of host stress granules on viral mRNAs and the nsp3-FXR2 complexes bind viral RNAs and probably orchestrate the assembly of viral replication complexes. The tandem Agenet-like domains preferentially recognize trimethylated histone peptides. Belongs to the FMR1 family.