Acts as catalytic component of the CCR4-NOT core complex, which in the nucleus seems to be a general transcription factor, and in the cytoplasm the major mRNA deadenylase involved in mRNA turnover. Exonucleolytic cleavage of poly(A) to 5'-AMP. Component of the CCR4-NOT complex, at least composed of CRR4 and CAF1 proteins. Belongs to the CCR4/nocturin family. Sequencing errors. Sequencing errors.