Figure 1.

Schematic drawing of the applications: in both cases, light induces nuclear entry of a protein admitting it to its region of activity. (a) A transcription factor (red) is kept in the cytoplasm. Photoactivation releases it to the nucleus where it initiates expression of proteins (green). (b) TEV-protease (blue) is kept in the cytoplasm and enters the nucleus after photoactivation. Proteins in the nucleus (green/red) with a TEV cleavage site will remain intact until the protease enters the nucleus and starts cleavage. Upon cleavage of the protein, its part containing the NLS will remain nuclear (green) whereas the other part (red) will distribute all over the cell.