Urotensin-II
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Urotensin-II
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| Identifiers | |
| Symbol | U-II |
| Entrez | 10911 |
| HUGO | 12636 |
| OMIM | 604097 |
| RefSeq | NM_021995 |
| UniProt | O95399 |
| Other data | |
| Locus | Chr. 1# p36 |
[edit] Introduction
Urotensin-II (U-II) is a peptide ligand, initially isolated from the neurosecretory system of the Goby fish (Gillichthys mirabilis) Bern et al. 1969. For many years it was thought that U-II does not exhibit significant effects in mammalian systems; a view quickly overturned when it was demonstrated that Goby U-II produces slow relaxation of mouse annococygeus muscle, in addition to contraction of rat artery segments. In 1998, the cDNA encoding a U-II precursor was cloned in man, unequivocally demonstrating its existence in mammalian species.
[edit] U-II Peptide
As with other peptide ligands, U-II is synthesised from a larger precursor molecule, known as Prepro-urotensin-II, two isoforms have been identified in man of lengths 124 and 139 residues. Cleavage of either of these precursors produces identical, eleven residue, mature U-II peptides. The cyclic, C-terminal hexapeptide sequence((-CYS*-TRY-LYS-TRP-PHE-CYS*-), (*bridged CYS residues)), has been conserved through evolution from lamprey to human, species which diverged some 560 million years ago. The fact that such a strong evolutionary pressure has acted to conserve this sequence, highlights its physiological importance, indeed this hexapeptide sequence confers biological activity.
