A genetically encoded fluorescent sensor of ERK activity

Christopher D. Harvey, Anka G. Ehrhardt, Cristina Cellurale, Haining Zhong, Ryohei Yasuda, Roger J. Davis, Karel Svoboda

Research output: Contribution to journalArticlepeer-review

261 Scopus citations


The activity of the ERK has complex spatial and temporal dynamics that are important for the specificity of downstream effects. However, current biochemical techniques do not allow for the measurement of ERK signaling with fine spatiotemporal resolution. We developed a genetically encoded, FRET-based sensor of ERK activity (the extracellular signal-regulated kinase activity reporter, EKAR), optimized for signal-to-noise ratio and fluorescence lifetime imaging. EKAR selectively and reversibly reported ERK activation in HEK293 cells after epidermal growth factor stimulation. EKAR signals were correlated with ERK phosphorylation, required ERK activity, and did not report the activities of JNK or p38. EKAR reported ERK activation in the dendrites and nucleus of hippocampal pyramidal neurons in brain slices after theta-burst stimuli or trains of back-propagating action potentials. EKAR therefore permits the measurement of spatiotemporal ERK signaling dynamics in living cells, including in neuronal compartments in intact tissues.

Original languageEnglish (US)
Pages (from-to)19264-19269
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number49
StatePublished - Dec 9 2008
Externally publishedYes


  • FRET
  • Fluorescence lifetime imaging microscopy
  • MAPK

ASJC Scopus subject areas

  • General


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