Open Access

Fluorescence resonance energy transfer (FRET) as a method to calculate the dimerization strength of basic Helix-Loop-Helix (bHLH) proteins

  • Victoria E. Centonze1,
  • Beth A. Firulli2 and
  • Anthony B. Firulli2Email author
Biological Procedures Online6:610078

DOI: 10.1251/bpo75

Received: 17 March 2004

Accepted: 3 May 2004


Post-translational modifications such as phosphorylation play a vital role in the regulation of protein function. In our study of the basic Helix-loop-Helix (bHLH) transcription factor HAND1, we show that HAND1 is phosphorylated during the trophoblast giant cell differentiation on residues residing in Helix I of the bHLH domain. Our hypothesis is that these modifications result in changes in HAND1 dimerization affinities with other bHLH factors. To test this idea, we employed FRET to measure the protein-protein interactions of HAND1 and HAND1 point mutants in HEK293 cells using YFP and CFP fusion proteins and laser scanning confocal microscopy.

Indexing terms

Phosphorylation Fluorescence Resonance Energy Transfer Transcription factors