Selenoprotein P, N-terminal (IPR007671)

Short name: Selenoprotein-P_N

Overlapping homologous superfamilies


Domain relationships



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 [PMID: 10775431]. It is thought to be glycosylated [PMID: 11168591]. SelP may have antioxidant properties. It can attach to epithelial cells, and may protect vascular endothelial cells against peroxynitrite toxicity [PMID: 10775431]. The high selenium content of SelP suggests that it may be involved in selenium intercellular transport or storage [PMID: 11168591]. The promoter structure of bovine SelP suggests that it may be involved in countering heavy metal intoxication, and may also have a developmental function [PMID: 9358058]. The N-terminal region of SelP can exist independently of the C-terminal region. Zebrafish selenoprotein Pb (Q98SV0) lacks the C-terminal Sec-rich region, and a protein encoded by the rat SelP gene and lacking this region has also been reported [PMID: 11168591]. 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 [PMID: 11168591]. 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 [PMID: 10775431].

The function of the bacterial members of this family is uncharacterised.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.