[Abstract]  [Full Text]  [PDF]

Victoria E. Centonze¹, Beth A. Firulli² and Anthony B. Firulli^2*

¹ Department of Cellular and Structural Biology University of Texas Health Science Center at San Antonio. USA.
² Wells Center for Pediatric Research, James Whitcomb Riley Hospital for Children, Departments of Pediatrics and Medical & Molecular Genetics, Indiana University Medical School. 1044 W. Walnut, R4 372, Indianapolis, IN. 46202-5225. USA.

* To whom correspondence should be addressed: Anthony B. Firulli, Wells Center for Pediatric Research, James Whitcomb Riley Hospital for Children, Departments of Pediatrics and Medical & Molecular Genetics, Indiana University Medical School. 1044 W. Walnut, R4 372, Indianapolis, IN. 46202-5225. USA. Email: tfirulli@iupui.edu

Biol. Proced. Online 2004;6:78-82. doi:10.1251/bpo75
Submitted: March 17, 2004; Accepted: May 03, 2004; Published: May 12, 2004.

Indexing terms: Phosphorylation; Fluorescence Resonance Energy Transfer; Transcription factors.

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.