Proislet Amyloid Polypeptide (ProIAPP)

proIAPP is the protein precursor for Islet amyloid polypeptide (IAPP, amylin) . ProIAPP is produced in the pancreatic beta cells (beta-cells) as a 67 amino acid, 7404 Dalton pro-peptide and undergoes post-translational modifications to become the 37 amino acid IAPP hormone, also known as amylin. IAPP is cosecreted with insulin from the pancreatic beta-cells in a ratio of approximately 100:1. Amylin plays a role in glycemic regulation by slowing gastric emptying and promoting satiety, thereby preventing post-prandial spikes in blood glucose levels. ProIAPP has been linked to Type 2 diabetes and the loss of islet beta-cells (Paulsson et al., 2005). Islet amyloid formation, initiated by the aggregation of proIAPP, may contribute to this progressive loss of islet β-cells. It is thought that proIAPP forms the first granules that allow for IAPP to aggregate and form amyloid which may lead to amyloid-induced apoptosis of beta-cells.