Acts as a probably 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. In vitro, POP2 has 3'-exoribonuclease activity with a preference for poly(A) RNAs, but also degrades poly(U) and poly(C) RNAs. Is part of a glucose-sensing system involved in growth control in response to glucose availability