Binds the poly(A) tail of mRNA. Appears to be an important mediator of the multiple roles of the poly(A) tail in mRNA biogenesis, stability and translation. In the cytoplasm, affects both translation and mRNA decay. Inhibits the polyadenylated RNA degradation by the Rrp41p 3'-->5' exonuclease in vitro. Binds with the 5'UTRs of PAB2, PAB3 and with a lower affinity with the 5'UTR of PAB5. Expressed predominantly in immature flowers. Detected in tapetum and pollen. Strongly expressed in immatures siliques. A.thaliana contains 8 PABP genes. Belongs to the polyadenylate-binding protein type-1 family.