This gene encodes a nuclear protein that functions in the regulation of polyadenylation and promotes gene expression. The protein forms a high-molecular weight complex with components of the polyadenylation machinery. It is thought to serve as a scaffold for recruiting regulatory factors to the polyadenylation complex. It also participates in 3'-end maturation of histone mRNAs, which do not undergo polyadenylation. The protein also localizes to the cytoplasmic plaques of tight junctions in some cell types. [provided by RefSeq, Jul 2008]