PARN, Nocturnin and Angel are three of the multiple deadenylases that have been 
described in eukaryotic cells. While each of these enzymes appear to target 
poly(A) tails for shortening and influence RNA gene expression levels and 
quality control, the enzymes differ in terms of enzymatic mechanisms, regulation 
and biological impact. The goal of this review is to provide an in depth 
biochemical and biological perspective of the PARN, Nocturnin and Angel 
deadenylases. Understanding the shared and unique roles of these enzymes in cell 
biology will provide important insights into numerous aspects of the 
post-transcriptional control of gene expression. This article is part of a 
Special Issue entitled: RNA Decay mechanisms.