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Non-selective ion channel activity of polymorphic human islet amyloid polypeptide (amylin) double channels

Jun Zhao1, Rundong Hu, Michele F M Sciacca

  • 1Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, USA. zhengj@uakron.edu.

Physical Chemistry Chemical Physics : PCCP
|December 20, 2013
PubMed

Insights

Amyloid peptide ion channels are key to neurodegenerative disease toxicity. This study reveals diverse human Islet amyloid polypeptide (hIAPP) channel structures and their non-ionic selectivity, offering new insights into toxicity mechanisms.

Area of Science:

  • Biophysics
  • Neuroscience
  • Molecular Biology

Background:

  • Amyloid peptides are implicated in neurodegenerative diseases.
  • Ion channel formation by amyloid peptides is a critical factor in cellular toxicity.
  • Understanding these channels is vital for developing (pre)clinical treatments.

Purpose of the Study:

  • To investigate the conformational states of human Islet amyloid polypeptide (hIAPP) double channels in lipid membranes.
  • To elucidate the ion selectivity and physicochemical mechanisms underlying amyloid-channel-induced toxicity.

Main Methods:

  • Atomistic simulations were employed to model channel structures.
  • Experimental techniques were used to validate simulation findings.
  • Ion selectivity was assessed for various channel conformations.

Main Results:

  • A broad range of conformational states for hIAPP double channels were identified.
  • Individual channels showed high selectivity for chloride ions over cations.
  • Polymorphic double channels exhibited non-ionic selectivity, differing from amyloid-beta channels.

Conclusions:

  • The co-existence of diverse hIAPP channel conformations and orientations dictates their non-ionic selectivity.
  • This study provides a comprehensive physicochemical mechanism for amyloid-channel-induced toxicity.
  • Findings contribute to a deeper understanding of neurodegenerative disease pathogenesis.

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