Poly A Binding Protein Interacting Protein 2B (PAIP2B)

Most mRNAs, except for histones, contain a 3-prime poly(A) tail. Poly(A)-binding protein (PABP) enhances translation by circularizing mRNA through its interaction with the translation initiation factor EIF4G1 and the poly(A) tail. Various PABP-binding proteins regulate PABP activity, including PAIP1, a translational stimulator, and PAIP2A and PAIP2B, translational inhibitors. The predicted protein contains 123 amino acids and has a calculated molecular mass of 14.2 kD. It has central and C-terminal PABP-binding domains and shares 59% amino acid identity with PAIP2A. Northern blot analysis detected PAIP2B transcripts of 6.5, 1.5, and 0.6 kb in most tissues examined. The longest transcript predominated in brain, and the shortest was more abundant in testis and liver.