Concentration-dependent transitions govern the subcellular localization of islet amyloid polypeptide

Mazin Magzoub, Andrew D. Miranker

Research output: Contribution to journalArticle

Abstract

Islet amyloid polypeptide (IAPP) is a peptide hormone cosecreted with insulin by pancreatic β-cells. In type II diabetes, IAPP aggregates in a process that is associated with β-cell dysfunction and loss of β-cell mass. The relationship between IAPP's conformational landscape and its capacity to mediate cell death remains poorly understood. We have addressed these unknowns by comparing the cytotoxic effects of sequence variants with differing α-helical and amyloid propensities. IAPP was previously shown to oligomerize cooperatively on binding to lipid bilayers. Here, comparable transitions are evident in cell culture and are associated with a change in subcellular localization to the mitochondria under toxic conditions. Notably, we find that this toxic gain of function maps to IAPP's capacity to adopt aggregated membrane-bound α-helical, and not β-sheet, states. Our findings suggest that upon α-helical mediated oligomerization, IAPP acquires cell-penetrating peptide (CPP) properties, facilitating access to the mitochondrial compartment, resulting in its dysfunction.

Original languageEnglish (US)
Pages (from-to)1228-1238
Number of pages11
JournalFASEB Journal
Volume26
Issue number3
DOIs
StatePublished - Mar 2012

Keywords

  • Alzheimer's disease
  • Amylin
  • Parkinson's disease

ASJC Scopus subject areas

  • Biotechnology
  • Biochemistry
  • Molecular Biology
  • Genetics

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