Polyadenylate-binding protein-interacting protein 1 is a protein that in humans is encoded by the PAIP1 gene.

The protein encoded by this gene interacts with poly(A)-binding protein and with the cap-binding complex eIF4A. It is involved in translational initiation and protein biosynthesis. Overexpression of this gene in COS7 cells stimulates translation. Alternative splicing occurs at this locus and three transcript variants encoding three distinct isoforms have been identified. [provided by RefSeq, Jul 2008].
Function: Acts as a coactivator in the regulation of translation initiation of poly(A)-containing mRNAs. Its stimulatory activity on translation is mediated via its action on PABPC1. Competes with PAIP2 for binding to PABPC1. Its association with EIF4A and PABPC1 may potentiate contacts between mRNA termini. May also be involved in translationally coupled mRNA turnover. 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.