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 down-regulation of MYB- and JUN-dependent transcription. Enhances ligand-dependent transcriptional activity of nuclear hormone receptors. May play a role in cell differentiation (By similarity). Homodimer. Component of the CCR4-NOT complex; distinct complexes seem to exist that differ in the participation of probably mutually exclusive catalytic subunits. Interacts with MYB, ATF2, RARA, RARB, RARG, RXRA, RXRB and RXRG. Identified in a complex with ATF2 bound to target DNA. Interacts with NANOS2. Directly interacts with ZNF335. NANOS2 promotes its localization to P-body. Detected in adult spleen, thymus, testis, bone marrow, lung and brain. Detected in embryonic brain, liver, lung, intestine, heart, kidney, thymus and spleen (at protein level). Belongs to the CNOT9 family.