Just like dual chain AR, except at least one of the fluorophores is a dye. Therefore, this is not fully genetically encoded.

References

Kraynov, V.S., Chamberlain, C.E., Bokoch, G.M., Schwartz, M. A., Slabaugh, S. and Hahn, K.M. Localized Rac activation dynamics visualized in living cells.  Science, 290: 333-337, 2000. Online article | PDF

Methods articles

Hodgson, L., Pertz, O., and Hahn, K.M. Design and Optimization of genetically encoded fluorescent biosensors: GTPase biosensors. Methods Cell Biol, 85:63-81, 2008. [Link downloads PDF] Online article
*Note: this older methods article contains a useful description of biosensor image analysis.

Hodgson, L. Nalbant, P. Shen, F., and Hahn, K. Imaging and photobleach correction of Mero-CBD, sensor of endogenous Cdc42 activation. Methods Enzymol., 406:140-156, 2006. Online article | PDF
*Note: this article is focused on dye-based biosensors, but includes a method to correct for bleaching of any fluorophore.

 

~ Updated 04/07/2021