Post-translational protein modifications (PTMs), such as acetylation, play an important role in mediating the function, expression, interactions, and localization of proteins. Thus, PTMs can regulate a variety of cellular processes such as cellular differentiation, signaling pathways, metabolism and even cancer development. Protein acetylation is a reversible process that is tightly regulated by lysine acetyltransferases (KATs) and lysine deacetylases (KDACs). Lysine acetylation of non-histone proteins has been reported to affect enzymatic activity, stability, and complex formation. However, the exact role of acetylation on non-histone substrates is protein-specific. Using PhosphositePlus, a mass spectrometry database, and a published dataset identifying acetylated lysine enriched substrates, revealed that Poly (A)-specific ribonuclease (PARN) may be post-translationally modified by acetylation. PARN is a 3’exoribonuclease: it can cleave nucleotides one-by-one from the 3’end of RNA. PARN’s exoribonuclease activity plays an important role in RNA maturation and degradation. PARN has the highest substrate affinity for adenosines; therefore it is referred to as a deadenylase. Adenosine repeats (poly (A)) on the 3’ end of RNA prevent mature transcripts from degradation by nucleases, especially during transport from the nucleus to the cytoplasm for translation. Thus, removal of poly (A) tails by deadenylase enzymes such as PARN promotes mRNA decay. Currently there are no reports confirming whether PARN can be acetylated and its functional importance. This study reveals that PARN is modified by acetylation and that acetylation plays a key role in mediating its enzymatic activity
