PAN3

PAN3 is a regulatory subunit of the Pan2–Pan3 deadenylase complex, a conserved cytoplasmic enzyme system that shortens poly(A) tails on eukaryotic mRNAs. By removing adenine residues from the 3′ end, the Pan2–Pan3 complex promotes mRNA decay and thereby influences gene expression and translation. PAN3 typically functions in concert with Pan2, which provides the catalytic activity; together they constitute a major cytoplasmic deadenylase in many organisms.

The protein is evolutionarily conserved across eukaryotes, with homologs identified in fungi, plants, and animals. While the exact sequence and domain organization can vary among species, PAN3 generally contains regions that mediate interaction with Pan2 and other RNA-binding or protein-interaction motifs that support its regulatory role in deadenylation. The complex is commonly associated with processing bodies (P bodies) in the cytoplasm, where mRNA decay and storage processes are coordinated.

PAN3 activity is modulated by cellular conditions and by interactions with other components of RNA metabolism, including the CCR4–NOT deadenylase complex and poly(A)-binding proteins. These interactions can influence the recruitment of substrates and the efficiency of deadenylation. Mutations or altered expression of PAN3 can lead to changes in poly(A) tail length and the stability of specific transcripts, affecting cellular gene expression programs.

Overall, PAN3 serves as a critical regulator of mRNA turnover through its role in the Pan2–Pan3 deadenylase complex, contributing to the control of gene expression in diverse eukaryotic systems.