Fluorescent protein expression assay

Some cellular assays also present the ability to measure kinase activation using recombinantly expressed intracellular sensor molecules that fluoresce in response to phosphorylation. These sensors are reviewed by Lawrence et al. (2007). The most interesting versions use yellow and blue fluorescent proteins to create a FRET through phosphorylation-induced folding with an intramolecular SH2 domain. SH2 domains are known to bind tightly to phosphotyrosine molecules and have been successfully shown to serve as phosphotyrosine detectors. In this type of assay, imaging is not necessary because the total fluorescence can be measured in a population of cells using a standard plate reader. 

Another much used yeast-based assay is the yEGFP assay (first described by Bovee et al., 2004). In this assay recombinant yeast cells are constructed that express the human estrogen reporter a (ER a) and yeast enhanced green fluorescence protein), the estrogenic potential is then measured by a Fluorometer. 

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