Molecular and functional characterization of amylin, a peptide associated with type 2 diabetes mellitus.

Abstract

The 37-amino acid peptide called amylin is a major component of the islet amyloid deposited in the pancreases of persons with type 2 diabetes mellitus. We report the isolation of a partial cDNA clone and a phage A genomic clone of the coding region of the amylin gene. The DNA sequence encodes a protein sequence identical to that of amylin isolated from the amyloid found in the diabetic pancreas and shows that amylin is likely to be synthesized as a precursor peptide, now named proamylin. We have demonstrated that the amylin gene is present on chromosome 12 and that it is probably transcribed in the islets of Langerhans. The sequences of the genes for amylin and the calcitonin gene-related peptides (CGRPs) show strong similarity, especially over their 5' coding regions, where both peptides have a conserved intramolecular disulfide bridge, and also over their 3' coding regions, where the presence of a glycine codon strongly suggests that the carboxylterminal residue of amylin, like that of CGRP, is amidated. To examine the functional relevance of these posttranslational modifications, the biological activity of amylin synthesized with or without the disulfide bridge and/or amidation was measured. It was found that both features are necessary for full biological activity, thereby confirming the functional importance of those regions of the molecule whose sequences are conserved at both protein and genetic levels.

Evidence for Conservation of the Calcitonin Superfamily and Activity-regulating Mechanisms in the Basal Chordate Branchiostoma floridae

“…1), which is reminiscent of vertebrate CGRP, adrenomedullin, and amylin ( Fig. 1B) (3,(25)(26)(27). In addition, the peptides contained a C-terminal Pro-NH 2 , which is characteristic of vertebrate CT (Fig.…”

Rutin suppresses human-amylin/hIAPP misfolding and oligomer formation in-vitro , and ameliorates diabetes and its impacts in human-amylin/hIAPP transgenic mice

“…1D) between hA and mA in the segment corresponding to NNFGAILSS (dashed line) in large part generate the amyloidogenic nucleus in hA that is largely responsible for its propensity to misfold, aggregate, elicit death by apoptosis of islet β-cells, and cause islet degeneration and diabetes [13]. The intramolecular disulphide bond and carboxyl-terminal amide group are required for physiological hormonal activity of hA [6,14].…”

Biotinyl analogues of amylin as biologically active probes for amylin/CGRP receptor recognition

“…However, it seems likely that an optimal spacer length between the peptide and the bulk of the attached derivative is required to fully prevent steric hindrance of receptor-ligand interactions. In this regard we have found that the N-terminal region of amylin and CGRP plays a role in receptor binding since reduction of the 2-7 disulphide bridge abolishes receptor recognition (C. Bacon and A. Chantry, unpublished observations) and biological activity [11]. The biotinylated analogues de-" scribed here have a spacer with a disulphide bridge and 8 atoms between the biotinyl carboxyl group and the N.terminal Lys.…”