Finite Phase-separation FRET II: Determination of domain size from simulated data

TL;DR

This paper introduces a new FP-FRET model that accurately estimates membrane domain sizes from simulated FRET data, even when some model assumptions are violated.

Contribution

The study develops and validates a Monte Carlo-based FP-FRET model capable of determining membrane domain sizes from FRET efficiency data.

Findings

FP-FRET can determine domain size within 5% for diameters up to ~5Ro.

The model estimates domain size within 15% for diameters up to ~20Ro.

The model's robustness was tested under invalid assumptions.

Abstract

We have developed a new model to describe FRET efficiency (E FRET) between freely-diffusing membrane probes in phase-separated bilayers (Finite Phase-separation FRET, or FP-FRET), that in principle applies to any system where phase domain dimensions are larger than ~Ro . Here we use Monte Carlo techniques to simulate E FRET for a range of probe partitioning behaviors and domain sizes, and then fit the simulated data to the FP-FRET model to recover simulation parameters. We find that FP-FRET can determine domain size to within 5% of simulated values for domain diameters up to ~ 5Ro, and to within 15% for diameters up to ~ 20Ro . We also investigated the performance of the model in cases where specific model assumptions are not valid.