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Processing of pro-islet amyloid polypeptide (proIAPP) by the prohormone convertase PC2
M K Badman1, K I Shennan, J L Jermany
1Department of Human Anatomy, University of Oxford, UK.
FEBS Letters
|January 15, 1996
Summary
Islet amyloid polypeptide (IAPP), or amylin, forms amyloid in Type 2 diabetes. Research shows the enzyme PC2 effectively processes proIAPP into mature IAPP, unlike PC3 or furin, suggesting a key role in beta-cell function.
Area of Science:
- Biochemistry
- Endocrinology
- Molecular Biology
Background:
- Islet amyloid polypeptide (IAPP), also known as amylin, is a key component of islet amyloid deposits observed in Type 2 diabetes.
- IAPP is synthesized in pancreatic islet beta-cells as a larger precursor, proIAPP, which undergoes proteolytic processing.
Purpose of the Study:
- To investigate the specific endopeptidases responsible for processing human proIAPP into mature IAPP.
- To determine the role of beta-cell endopeptidases PC2, PC3, and furin in proIAPP maturation.
Main Methods:
- Utilized an in vitro translation/translocation system to analyze the processing of human proIAPP.
- Examined the enzymatic activity of PC2, PC3, and furin on proIAPP.
Main Results:
- ProIAPP was efficiently converted to mature IAPP by the endopeptidase PC2.
- Minimal conversion of proIAPP to mature IAPP was observed with furin and PC3.
- These findings support the hypothesis that proIAPP processing occurs within beta-cell secretory granules.
Conclusions:
- PC2 is the primary endopeptidase responsible for processing proIAPP to mature IAPP in beta-cells.
- Aberrant cellular proteolysis in Type 2 diabetes may contribute to the accumulation of IAPP and subsequent amyloidosis.