Rapid blue-light–mediated induction of protein interactions in living cells

Dimerizers allowing inducible control of protein-protein interactions are powerful tools for manipulating biological processes. Here we describe genetically encoded light-inducible protein-interaction modules based on Arabidopsis thaliana cryptochrome 2 and CIB1 that require no exogenous ligands and dimerize on blue-light exposure with subsecond time resolution and subcellular spatial resolution. We demonstrate the utility of this system by inducing protein translocation, transcription and Cre recombinase-mediated DNA recombination using light.