Islet amyloid polypeptide (IAPP), 'amylin', is the component peptide of islet amyloid formed in Type 2 diabetes. IAPP is expressed in islet β-cells and is derived from a larger precursor, proIAPP, by proteolysis. An in vitro translation/ translocation system was used to separately examine processing of human proIAPP by the β-cell endopeptidases PC2, PC3 or furin. ProIAPP was converted to mature IAPP by PC2 but there was little conversion by furin or PC3. These data are consistent with processing of proIAPP in β-cell secretory granules. Abnormal cellular proteolysis associated with type 2 diabetes could contribute to IAPP amyloidosis.
- Islet amyloid polypeptide
- Propeptide processing