Multiplex imaging of Rho family GTPase activities in living cells.

Here, we provide procedures for imaging the Rho GTPase biosensors in both single and multiplex acquisition modes. The multiplex approach enables the direct visualization of two biosensor readouts from a single living cell. Here, we take as an example a combination of the RhoA biosensor based on a CFP/YFP FRET modality and the Cdc42 biosensor based on organic dyes that change fluorescence as a function of the local solvent polarity. We list the required optical components as well as cellular manipulation techniques necessary to successfully image these two ratiometric biosensors in a single living cell.