FRET-enhanced photostability allows improved single-molecule tracking of proteins and protein complexes in live mammalian cells

Nat Commun. 2018 Jun 28;9(1):2520. doi: 10.1038/s41467-018-04486-0.


A major challenge in single-molecule imaging is tracking the dynamics of proteins or complexes for long periods of time in the dense environments found in living cells. Here, we introduce the concept of using FRET to enhance the photophysical properties of photo-modulatable (PM) fluorophores commonly used in such studies. By developing novel single-molecule FRET pairs, consisting of a PM donor fluorophore (either mEos3.2 or PA-JF549) next to a photostable acceptor dye JF646, we demonstrate that FRET competes with normal photobleaching kinetic pathways to increase the photostability of both donor fluorophores. This effect was further enhanced using a triplet-state quencher. Our approach allows us to significantly improve single-molecule tracking of chromatin-binding proteins in live mammalian cells. In addition, it provides a novel way to track the localization and dynamics of protein complexes by labeling one protein with the PM donor and its interaction partner with the acceptor dye.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Chromatin / chemistry*
  • Chromatin / metabolism
  • Fluorescence Resonance Energy Transfer
  • Fluorescent Dyes / chemistry
  • Genes, Reporter
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • Mice
  • Microscopy, Fluorescence / methods*
  • Mouse Embryonic Stem Cells / metabolism*
  • Mouse Embryonic Stem Cells / ultrastructure
  • Photobleaching
  • Single Molecule Imaging / methods*


  • Chromatin
  • Fluorescent Dyes
  • Green Fluorescent Proteins