The poly(A)-specific nuclease (PAN) is a deadenylating enzyme involved in cytoplasmic mRNA turnover consisting of two subunits, PAN2 and PAN3 that form a conserved complex which acts in the initial trimming of poly(A) tails during deadenylation, followed by the processive activity of CCR4-NOT complex [1]. PAN2 has two independent structural units, the C-terminal catalytic unit (including Pfam:PF13423 and Pfam:PF00929) and the N-terminal assembly unit, represented in this entry, which engages in a bipartite interaction with PAN3 dimers [2]. This assembly unit contains a WD40 propeller that contacts the PAN3 C-terminal domain and it is connected to an adaptable linker which reinforces the asymmetry of the PAN3 dimer preventing the recruitment of a second PAN2 molecule [2].

1: The structure of the Pan2-Pan3 core complex reveals cross-talk between deadenylase and pseudokinase. Schafer IB, Rode M, Bonneau F, Schussler S, Conti E; Nat Struct Mol Biol. 2014;21:591-598. PMID:24880344

2: An asymmetric PAN3 dimer recruits a single PAN2 exonuclease to mediate mRNA deadenylation and decay. Jonas S, Christie M, Peter D, Bhandari D, Loh B, Huntzinger E, Weichenrieder O, Izaurralde E; Nat Struct Mol Biol. 2014;21:599-608. PMID:24880343