mRNA-binding protein that plays a key role in self- renewal of erythroid cells in response to glucocorticoids. Specifically binds to the AU-rich element (ARE) in the 3'-UTR of target mRNAs; promoting their deadenylation and degradation (PubMed:14981510). Specifically expressed in burst-forming unit- erythroid (BFU-E) progenitors in response to glucocorticoids and acts as a negative regulator of erythroid cell differentiation: promotes self-renewal of erythroid cells by binding mRNAs that are induced or highly expressed during terminal erythroid differentiation and promotes their degradation; preventing erythroid cell differentiation. Down-regulated during erythroid differentiation from the BFU-E stage; stabilizing mRNAs required for terminal differentiation (By similarity). {ECO:0000250; ECO:0000269|PubMed:14981510}.