RNA-binding protein involved in translationally coupled mRNA turnover (PubMed:11051545, PubMed:15314026). Implicated with other RNA-binding proteins in the cytoplasmic deadenylation/translational and decay interplay of the FOS mRNA mediated by the major coding-region determinant of instability (mCRD) domain (PubMed:11051545, PubMed:15314026). Required for efficient formation of stress granules (PubMed:29395067). (Microbial infection) Required for internal initiation of translation of human rhinovirus RNA. Component of a multi subunit autoregulatory ribonucleoprotein complex (ARC), at least composed of IGF2BP1, PABPC1 and CSDE1 (PubMed:16356927). Interacts with STRAP (PubMed:10049359). Part of a complex associated with the FOS mCRD domain and consisting of PABPC1, PAIP1, HNRPD and SYNCRIP (PubMed:11051545). The interaction with PABPC1 is direct and RNA-independent (PubMed:11051545, PubMed:15314026). Interacts with EIF4ENIF1/4E-T (PubMed:27342281, PubMed:32354837). Extended N-terminus.