Pan2 is a catalytic 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 [, ]. Pan2 is involved in the initial stage of deadenylation of mRNA, which is required for poly(A) tail shortening []. Regulation of mRNA decay rates in eukaryotic cells affects gene expression []. The Pan2-Pan3 complex shortens cytoplasmic mRNA 3' polyA tails to regulate mRNA stability []. In the complex Pan2 provides the catalytic activity, whereas Pan3 mediates Pan2 recruitment tomRNA targets [].
The poly(A)-specific nuclease (PAN) is a deadenylating enzyme involved in cytoplasmic mRNA turnover and consists of two subunits, PAN2 and PAN3, which form a conserved complex acting in the initial trimming of poly(A) tails, a process followed by the processive action of CCR4-NOT complex. PAN2 is the catalytic subunit and has two independent structural units, the N-terminal assembly unit which engages in a bipartite interaction with PAN3 dimers and the C-terminal catalytic unit [, , ]. The C-terminal unit contains the ubiquitin C-terminal hydrolase (UCH) domain, represented in this entry, and a RNase domain of the DEDD superfamily () [, ].
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 [, ]. It contains a PABP-interacting motif 2 (PAM2) that binds to the C-terminal domain of polyA binding proteins (PABPs) []. It recruits the Pan2-Pan3 complex to mRNA through the Pan3-PABP interaction [].Regulation of mRNA decay rates in eukaryotic cells affects gene expression []. The Pan2-Pan3 complex shortens cytoplasmic mRNA 3' polyA tails to regulate mRNA stability []. In the complex Pan2 provides the catalytic activity, whereas Pan3 mediates Pan2 recruitment to mRNA targets [].
