Calcitonin gene-related peptide (IPR015476)
Short name: Calcitonin_gene-rel_peptide
Overlapping homologous superfamilies
The calcitonin (CT) gene is alternatively expressed in a tissue-specific manner, producing either the calcium regulatory hormone CT in the thyroid, or the neuropeptide calcitonin gene related peptide (CGRP) in the brain [PMID: 2985435]. In medullary carcinoma of the thyroid, both peptides are produced [PMID: 2985435].
The calcitonin regulatory hormone is a peptide of 32 residues that causes a rapid but short-lived drop in calcium and phosphate levels in the blood by promoting the incorporation of these ions in the bones [PMID: 3060108]. The structure of Oncorhynchus sp. (Salmon) calcitonin has been studied by 2D NMR in SDS micelles [PMID: 1931969]. The main conformational feature of the hormone is an alpha-helix from residues 6-22, which includes an amphipathic segment. Two cysteine residues (at positions 1 and 7) form an N-terminal loop, and a C-terminal decapeptide forms a loop that folds back towards the helix [PMID: 1931969].
CGRP is a 37-residue peptide produced by alternative splicing of the CT gene. CGRP induces vasodilation in various vessels, including those of the coronary, cerebral and systemic vasculature. A neurotransmitter or neuro-modulator role is suggested by its abundance in the CNS [PMID: 2985435]. The structure of human CGRP has been determined by 1H NMR [PMID: 1988044]. The main conformational feature of the hormone is an N-terminal disulphide-bonded loop (residues 2-7), leading into a well-defined alpha-helix between residues 8 and 18; thereafter, the structure is predominantly disordered, although there are indications of a preference for a turn-type conformation between residues 19 and 21 [PMID: 1988044].
This entry represents the full-length propeptide (procalcitonin gene-related peptide or proCGRP) before cleavage into the calcitonin peptide.
- PR00817 (CALCITONINB)