SelP is the only known eukaryotic selenoprotein that contains multiple selenocysteine (Sec) residues, and accounts for more than 50% of the selenium content of rat and human plasma []. It is thought to be glycosylated []. SelP may have antioxidant properties. It can attach to epithelial cells, and may protect vascular endothelial cells against peroxynitrite toxicity []. The high selenium content of SelP suggests that it may be involved in selenium intercellular transport or storage []. The promoter structure of bovine SelP suggests that it may be involved in countering heavy metal intoxication, and may also have a developmental function []. The N-terminal region always contains one Sec residue, and this is separated from the C-terminal region (9-16 sec residues) by a histidine-rich sequence []. The large number of Sec residues in the C-terminal portion of SelP suggests that it may be involved in selenium transport or storage. However, it is also possible that this region has a redox function [].
SelP is the only known eukaryotic selenoprotein that contains multiple selenocysteine (Sec) residues, and accounts for more than 50% of the selenium content of rat and human plasma []. It is thought to be glycosylated []. SelP may have antioxidant properties. It can attach to epithelial cells, and may protect vascular endothelial cells against peroxynitrite toxicity []. The high selenium content of SelP suggests that it may be involved in selenium intercellular transport or storage []. The promoter structure of bovine SelP suggests that it may be involved in countering heavy metal intoxication, and may also have a developmental function [].This entry represents the N-terminal region of SelP, which can exist independently of the C-terminal region. The N terminus is larger, contains less Selenium and is thought to be heavily glycosylated. It appears to supply selenium to the kidney []. Zebrafish selenoprotein Pb () lacks the C-terminal Sec-rich region, and a protein encoded by the rat SelP gene and lacking this region has also been reported []. The N-terminal region contains a conserved SecxxCys motif, which is similar to the CysxxCys found in thioredoxins. It is speculated that the N-terminal region may adopt a thioredoxin fold and catalyse redox reactions []. The N-terminal region also contains a His-rich region, which is thought to mediate heparin binding. Binding to heparan proteoglycans could account for the membrane binding properties of SelP [].The function of the bacterial members of this family is uncharacterised.
