The function of cytoplasmic PABPs [poly(A)-binding proteins] in promoting mRNA 
translation has been intensively studied. However, PABPs also have less clearly 
defined functions in mRNA turnover including roles in default deadenylation, a 
major rate-limiting step in mRNA decay, as well as roles in the regulation of 
mRNA turnover by cis-acting control elements and in the detection of aberrant 
mRNA transcripts. In the present paper, we review our current understanding of 
the complex roles of PABP1 in mRNA turnover, focusing on recent progress in 
mammals and highlighting some of the major questions that remain to be 
addressed.