Selenoprotein P (SeP) is a plasma protein that contains up to 10 selenocysteine residues and accounts for about 50% of total selenium in human plasma. We have previously shown that SeP expression in the human liver cell line HepG2 is inhibited by transforming growth factor (TGF)-b1 on a transcriptional level. Smad proteins are the transcriptional mediators of TGF-b signalling and putative Smad-binding elements (SBE) comprising the core sequence CAGACA are present at two positions in the SeP promoter
