Poly(A) nuclease involved in mRNA decay. Has 3'-5' RNase activity (PubMed:20634287). The CCR4-NOT complex functions as general transcription regulation complex (By similarity). Enhances ligand-dependent transcriptional activity of nuclear hormone receptors (By similarity). Exonucleolytic cleavage of poly(A) to 5'-AMP. Binds 2 magnesium ions, but the ions interact each with only 1 or 2 residues. Subunit of the CCR4-NOT core complex. Predominantly cytoplasmic. Belongs to the CCR4/nocturin family.