InterPro domain: IPR030844

Pan3 is a regulatory subunit of the poly(A)-nuclease (PAN) deadenylation complex, one of the two eukaryotic poly(A) nuclease complexes (Ccr4-Caf1 and Pan2-Pan3) involved in mRNA decay [ 1 , 2 ]. It contains a PABP-interacting motif 2 (PAM2) that binds to the C-terminal domain of polyA binding proteins (PABPs) [ 3 ]. It recruits the Pan2-Pan3 complex to mRNA through the Pan3-PABP interaction [ 4 ].

Regulation of mRNA decay rates in eukaryotic cells affects gene expression [ 5 ]. The Pan2-Pan3 complex shortens cytoplasmic mRNA 3' polyA tails to regulate mRNA stability [ 6 ]. In the complex Pan2 provides the catalytic activity, whereas Pan3 mediates Pan2 recruitment to mRNA targets [ 7 ].

1. Concerted action of poly(A) nucleases and decapping enzyme in mammalian mRNA turnover. Nat. Struct. Mol. Biol. 12, 1054-63
2. The yeast Pan2 protein is required for poly(A)-binding protein-stimulated poly(A)-nuclease activity. J. Biol. Chem. 271, 432-8
3. Poly(A) nuclease interacts with the C-terminal domain of polyadenylate-binding protein domain from poly(A)-binding protein. J. Biol. Chem. 282, 25067-75
4. An asymmetric PAN3 dimer recruits a single PAN2 exonuclease to mediate mRNA deadenylation and decay. Nat. Struct. Mol. Biol. 21, 599-608
5. The cap-to-tail guide to mRNA turnover. Nat. Rev. Mol. Cell Biol. 2, 237-46
6. Structural basis for Pan3 binding to Pan2 and its function in mRNA recruitment and deadenylation. EMBO J. 33, 1514-26