Acts as a repressor in the regulation of translation initiation of poly(A)-containing mRNAs. Its inhibitory activity on translation is mediated via its action on PABPC1. Displaces the interaction of PABPC1 with poly(A) RNA and competes with PAIP1 for binding to PABPC1. Its association with PABPC1 results in disruption of the cytoplasmic poly(A) RNP structure organization (By similarity). Only the PABPC1-interacting motif-1 (PAM1) interferes with the binding of PABPC1 to poly(A) RNA and translation initiation. Ubiquitinated, leading to its degradation by the proteasome. Belongs to the PAIP2 family.