Has 3'-5' poly(A) exoribonuclease activity for synthetic poly(A) RNA substrate (PubMed:19276069, PubMed:20634287, PubMed:31439799). Its function seems to be partially redundant with that of CNOT8 (PubMed:19605561). 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 (PubMed:19276069, PubMed:20634287, PubMed:31439799). During miRNA- mediated repression the complex also seems to act as translational repressor during translational initiation (PubMed:20065043). Additional complex functions may be a consequence of its influence on mRNA expression (PubMed:19276069, PubMed:23236473). Associates with members of the BTG family such as TOB1 and BTG2 and is required for their anti- proliferative activity (PubMed:19276069, PubMed:23236473). {ECO:0000269|PubMed:19276069, ECO:0000269|PubMed:19605561, ECO:0000269|PubMed:20065043, ECO:0000269|PubMed:20634287, ECO:0000269|PubMed:23236473, ECO:0000269|PubMed:31439799}. This is the function of CNOT7 (CCR4-NOT transcription complex subunit 7, Ensembl gene identifier ENSG00000198791).