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. Required for the CCR4-NOT complex structural integrity. Can repress transcription and may link the CCR4-NOT complex to transcriptional regulation; the repressive function may specificly involve the N-Cor repressor complex containing HDAC3, NCOR1 and NCOR2. Involved in the maintenance of emryonic stem (ES) cell identity.Albert T.K., Nucleic Acids Res. 28:809-817(2000).Zhang Q.-H., Genome Res. 10:1546-1560(2000).Ota T., Nat. Genet. 36:40-45(2004).