Investigating the Correlation between Type-II Diabetes Mellitus and Islet Amyloid Polypeptide Aggregation in Various Mammalian Species

Kate Alexandra Menefee
David A. Moffet Ph.D., Loyola Marymount University


The leading theory regarding the mechanism of type-II diabetes mellitus involves amyloid fiber formation and aggregation, resulting in the death of the insulin-producing pancreatic ß-cells. Islet amyloid polypeptide (IAPP) forms fibrils that surround human pancreatic cells. These fibrils induce cellular apoptosis. However, IAPP does not form fibrils within organisms of all species. It is necessary to determine which species have aggregative IAPP sequences in order to better understand the inherent amyloidogenicity of the amino acid sequences themselves. In this study, the amyloidogenicity of the IAPP sequences of fourteen organisms was analyzed using thioflavin-T assays, atomic force microscopy (AFM), and immunodetection dot blot assays (Dot Blot). It is apparent that certain highly-conserved amino acids are crucial for IAPP aggregation and therefore play a large role in the onset of type-II diabetes.