ABSTRACT
The application of optogenetic tools aims at controlling important cellular functions by light. Optogenetic approaches in microorganisms are currently in focus due to their importance for biotechnology applications. Efficient optogenetic control of protein abundance is best achieved with concomitant manipulation of target protein synthesis and stability. Variability of protein levels is reachable by using different illumination conditions and/or exchanging parts of the optogenetic tools using modules of different light sensitivity or different activity. In this chapter, we present an overview of optogenetic modules to control protein stability via the photo-sensitive degron and transcription by the photo-sensitive transcription factor. The combined application of these modules results in synergistic optogenetic multistep control that reaches high switching light/dark ratios. A facile protocol is given subsequently with respect to how to implement this approach for manipulating a target protein in yeast in a two-step process, with two examples provided to illustrate the procedure. An outlook on further adaptations of these optogenetic devices is also provided to tweak these modules to a specific application.
