Identified in a histone pre-mRNA complex, at least composed of ERI1, LSM11, SLBP, SNRPB, SYNCRIP and YBX1 (By similarity). Component of the coding region determinant (CRD)-mediated complex, composed of DHX9, HNRNPU, IGF2BP1, SYNCRIP and YBX1. Identified in a mRNP complex, at least composed of DHX9, DDX3X, ELAVL1, HNRNPU, IGF2BP1, ILF3, PABPC1, PCBP2, PTBP2, STAU1, STAU2, SYNCRIP and YBX1. Identified in a mRNP granule complex, at least composed of ACTB, ACTN4, DHX9, ERG, HNRNPA1, HNRNPA2B1, HNRNPAB, HNRNPD, HNRNPL, HNRNPR, HNRNPU, HSPA1, HSPA8, IGF2BP1, ILF2, ILF3, NCBP1, NCL, PABPC1, PABPC4, PABPN1, RPLP0, RPS3, RPS3A, RPS4X, RPS8, RPS9, SYNCRIP, TROVE2, YBX1 and untranslated mRNAs. Component of the U11/U12 snRNPs that are part of the U12-type spliceosome. Interacts with IGF2BP1 and RBBP6. Component of cytoplasmic messenger ribonucleoprotein particles (mRNPs). Interacts with AKT1, MBNL1, SFRS9, ALYREF/THOC4, MSH2, XRCC5, WRN and NCL. Can bind to DNA as a homomeric form, (EFI-A)n or as a heteromeric form in association with EFI-B. Homodimer in the presence of ATP. Interacts (via C-terminus) with APEX1 (via N-terminus); the interaction is increased with APEX1 acetylated at 'Lys-6' and 'Lys-7'. Interacts with EIF2C1 and EIF2C2.