FLIM-FRET Analysis of Ras Nanoclustering and Membrane-Anchorage

Hanna Parkkola, Farid Ahmad Siddiqui, Christina Oetken-Lindholm, Daniel Abankwa*

*Corresponding author for this work

Research output: Chapter in Book/Conference proceedingChapterScientificpeer-review

3 Citations (Scopus)


On the plasma membrane, Ras is organized into laterally segregated proteo-lipid complexes called nanoclusters. The extent of Ras nanoclustering correlates with its signaling output, positioning nanocluster as dynamic signaling gain modulators. Recent evidence suggests that stacked dimers of Ras and Raf are elemental units at least of one type of Ras nanocluster. However, it is still incompletely understood, in which physiological contexts nanoclustering is regulated and which constituents are parts of nanocluster. Nonetheless, disruption of nanoclustering faithfully diminishes Ras activity in cells, suggesting Ras nanocluster as potential drug targets. While there are several methods available to study Ras nanocluster, fluorescence or Förster resonance energy transfer (FRET) between fluorescently labeled, nanoclustered Ras proteins is a relatively simple readout. FRET measurements using fluorescence lifetime imaging microscopy (FLIM) have proven to be robust and sensitive to determine Ras nanoclustering changes. Loss of FRET that emerges due to nanoclustering reports on all processes upstream of Ras nanoclustering, i.e., also on proper trafficking or lipid modification of Ras. Here we report our standard FLIM-FRET protocol to measure nanoclustering-dependent FRET of Ras in mammalian cells. Importantly, nanoclustering-dependent FRET is one of the few methods that can detect differences between the Ras isoforms.

Original languageEnglish
Title of host publicationRas Activity and Signaling
Subtitle of host publicationMethods and Protocols
PublisherHumana Press Inc.
Number of pages18
ISBN (Print)978-1-0716-1190-6
Publication statusPublished - 2021
MoE publication typeA3 Part of a book or another research book

Publication series

NameMethods in Molecular Biology
ISSN (Print)1064-3745
ISSN (Electronic)1940-6029


  • FLIM
  • FRET
  • GTPase
  • Nanocluster
  • Plasma membrane
  • Ras


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