Binds the poly(A) tail of mRNA (PubMed:2125288). Since it interacts with the cap-associating translation initiation factor eIF4G, it is likely that it functions by linking Atx2 to the cap-binding complex (PubMed:28388438). Forms a complex with tyf and Atx2 which functions in adult circadian pacemaker neurons to sustain circadian rhythms likely by switching between activator and repressor modes of post-transcriptional regulation via interaction with Lsm12a or me31B, respectively (PubMed:28388438). The activator complex (Atx2-tyf activator complex) activates the TYF-dependent translation of per to maintain 24 hour periodicity in circadian locomotor behaviors, whereas the repressor complex (Atx2-Not1 repressor complex) promotes Not1-dependent post-transcriptional gene silencing and supports high-amplitude circadian rhythms in a per-independent manner (PubMed:28388438). In 0-1 hour embryos, forms a ribonucleoprotein complex (RNP) with me31B, eIF4E1, tral and cup which binds to various mRNAs including maternal mRNAs, and down-regulates their expression during the maternal-to-zygotic transition (PubMed:28875934). Core component of the neuromuscular Atx2 complex, composed of at least Atx2, tyf, pAbp, Lsm12a (PubMed:28388438). Interacts with Atx2 (via PAM2 motif) (PubMed:28388438). Atx2 and pAbp form a subcomplex that can associate with the 5' cap of pre-mRNAs independently of tyf, Lsm12a or me31B (PubMed:28388438). Forms a ribonucleoprotein complex (RNP) containing at least me31B, eIF4E1, cup, tral and pAbp; this interaction is required for the translational silencing of maternal mRNAs during the maternal-to-zygotic transition (PubMed:28875934). In 1-5 hour embryos, interaction with me31B is severely reduced and there is no detected interaction with cup and tral, however interaction with eIF4E1 and eIF4G1 remains unchanged (PubMed:28875934). Interacts with gw; this interaction interferes with the binding of pAbp to eIF4G and is required for miRNA-mediated silencing (PubMed:19797087). Interacts with larp (PubMed:19631203). Expressed during the first 5 hrs of embryogenesis (at protein level) (PubMed:28875934). Expressed both maternally and zygotically throughout development (PubMed:2125288). Belongs to the polyadenylate-binding protein type-1 family.