title: Bayesian total internal reflection fluorescence correlation spectroscopy reveals hIAPP-induced plasma membrane domain organization in live cells.
abstract: Amyloid fibril deposition of human islet amyloid polypeptide (hIAPP) in pancreatic islet cells is implicated in the pathogenesis of type II diabetes. A growing number of studies suggest that small peptide aggregates are cytotoxic via their interaction with the plasma membrane, which leads to membrane permeabilization or disruption. A recent study using imaging total internal reflection-fluorescence correlation spectroscopy (ITIR-FCS) showed that monomeric hIAPP induced the formation of cellular plasma membrane microdomains containing dense lipids, in addition to the modulation of membrane fluidity. However, the spatial organization of microdomains and their temporal evolution were only partially characterized due to limitations in the conventional analysis and interpretation of imaging FCS datasets. Here, we apply a previously developed Bayesian analysis procedure to ITIR-FCS data to resolve hIAPP-induced microdomain spatial organization and temporal dynamics. Our analysis enables the visualization of the temporal evolution of multiple diffusing species in the spatially heterogeneous cell membrane, lending support to the carpet model for the association mode of hIAPP aggregates with the plasma membrane. The presented Bayesian analysis procedure provides an automated and general approach to unbiased model-based interpretation of imaging FCS data, with broad applicability to resolving the heterogeneous spatial-temporal organization of biological membrane systems.
authors.affiliation: Laboratory for Computational Biology & Biophysics, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts.
authors.forename: Syuan-Ming
authors.initials: SM
authors.lastname: Guo
authors.affiliation: Departments of Biological Sciences and Chemistry, and Centre for Bioimaging Sciences, National University of Singapore, Singapore.
authors.forename: Nirmalya
authors.initials: N
authors.lastname: Bag
authors.affiliation: Departments of Biological Sciences and Chemistry, and Centre for Bioimaging Sciences, National University of Singapore, Singapore.
authors.forename: Aseem
authors.initials: A
authors.lastname: Mishra
authors.affiliation: Departments of Biological Sciences and Chemistry, and Centre for Bioimaging Sciences, National University of Singapore, Singapore. Electronic address: twohland@nus.edu.sg.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Wohland
authors.affiliation: Laboratory for Computational Biology & Biophysics, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts. Electronic address: mark.bathe@mit.edu.
authors.forename: Mark
authors.initials: M
authors.lastname: Bathe
mesh_terms: D001499:Bayes Theorem; D045744:Cell Line, Tumor; D006801:Humans; D058228:Islet Amyloid Polypeptide / Q000378:metabolism*; D021962:Membrane Microdomains / Q000378:metabolism / Q000648:ultrastructure*; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D013050:Spectrometry, Fluorescence
chemical_list: D058228:Islet Amyloid Polypeptide