Poly(A) nuclease with 3'-5' RNase activity. Catalytic component of the CCR4-NOT complex which is one of the major cellular mRNA deadenylases and is linked to various cellular processes including bulk mRNA degradation, miRNA-mediated repression, translational repression during translational initiation and general transcription regulation. Additional complex functions may be a consequence of its influence on mRNA expression. Involved in mRNA decay mediated by the major-protein-coding determinant of instability (mCRD) of the FOS gene in the cytoplasm. In the presence of ZNF335, enhances ligand-dependent transcriptional activity of nuclear hormone receptors. Mediates cell proliferation and cell survival and prevents cellular senescence. Exonucleolytic cleavage of poly(A) to 5'-AMP. Binds 2 magnesium ions, but the ions interact each with only 1 or 2 residues. Component of the CCR4-NOT complex; distinct complexes seem to exist that differ in the participation of probably mutually exclusive catalytic subunits; the complex contains two deadenylase subunits, CNOT6 or CNOT6L, and CNOT7 or CNOT8. Interacts with CNOT7 and CNOT8 (By similarity). Interacts with UNR (PubMed:15314026). Interacts with ZFP36L1 (via N-terminus). Interacts with ZNF335 (By similarity). Predominantly cytoplasmic. Expressed in embryonic stem (ES) cells. Belongs to the CCR4/nocturin family.