Membrane destabilization by monomeric hIAPP observed by imaging fluorescence correlation spectroscopy
Nirmalya Bag1, Ashraf Ali, Virander Singh Chauhan
1Departments of Biological Sciences and Chemistry and NUS Centre for Bio-Imaging Sciences (CBIS), National University of Singapore, 117557, Singapore. twohland@nus.edu.sg.
Chemical Communications (Cambridge, England)
|August 30, 2013
Summary
Monomeric human islet amyloid polypeptide (hIAPP) destabilizes cell membranes by increasing fluidity. This suggests hIAPP aggregation may not be required for its toxic effects on cells.
Area of Science:
- Biochemistry
- Cell Biology
- Membrane Biophysics
Background:
- Human islet amyloid polypeptide (hIAPP) is implicated in Type 2 diabetes.
- The mechanism of hIAPP-induced cytotoxicity remains incompletely understood.
- Membrane destabilization is a proposed pathway for hIAPP toxicity.
Purpose of the Study:
- To investigate the interaction of monomeric hIAPP with cell membranes.
- To determine the role of hIAPP aggregation in membrane destabilization and cytotoxicity.
- To elucidate the molecular mechanisms underlying hIAPP-membrane interactions.
Main Methods:
- Utilized model lipid bilayers and live cell imaging.
- Performed biophysical assays to measure membrane fluidity and lipid extraction.
- Analyzed hIAPP concentration-dependent effects on membrane integrity.
Main Results:
- Monomeric hIAPP significantly increases membrane fluidity.
- hIAPP interacts with membranes through carpet formation.
- Lipid extraction from membranes occurs in a concentration-dependent manner.
Conclusions:
- Monomeric hIAPP directly destabilizes both model and live cell membranes.
- The proposed mechanism involves carpet formation and lipid extraction.
- hIAPP aggregation may not be a prerequisite for its cytotoxic effects on cell membranes.
