Design, characterization and in vivo functioning of a light-dependent histidine protein kinase in the yeast Saccharomyces cerevisiae

Optogenetic strategies for the control of gene expression in yeasts

Optogenetics involves the use of light to control cellular functions and has become increasingly popular in various areas of research, especially in the precise control of gene expression. While this technology is already well established in neurobiology and basic research, its use in bioprocess development is still emerging. Some optogenetic switches have been implemented in yeasts for different purposes, taking advantage of a wide repertoire of biological parts and relatively easy genetic manipulation. In this review, we cover the current strategies used for the construction of yeast strains to be used in optogenetically controlled protein or metabolite production, as well as the operational aspects to be considered for the scale-up of this type of process. Finally, we discuss the main applications of optogenetic switches in yeast systems and highlight the main advantages and challenges of bioprocess development considering future directions for this field.

Development of a Light-Dependent Protein Histidine Kinase

Phosphorylation plays a critical role in facilitating signal transduction in prokaryotic and eukaryotic organisms. Our study introduces a tool for investigation of signal diffusion in a biochemical regulation network through the design and characterization of a light-stimulated histidine kinase that consists of the LOV domain from YtvA from Bacillus subtilis and the histidine kinase domain Sln1 from Saccharomyces cerevisiae. We show that blue light can be used as a trigger for modulation of the phosphorylation events in this engineered two-component signal transduction pathway in a eukaryotic cell. At the same time, we demonstrate the robustness of LOV domains and their utility for designing fusion proteins for signal transduction that can be triggered with (blue) light, providing a ready toolkit to design blue light dependent two-component signalling pathways.

Manipulation of Bacterial Signaling Using Engineered Histidine Kinases

Two-component systems allow bacteria to respond to changes in environmental or cytosolic conditions through autophosphorylation of a histidine kinase (HK) and subsequent transfer of the phosphate group to its downstream cognate response regulator (RR). The RR then elicits a cellular response, commonly through regulation of transcription. Engineering two-component system signaling networks provides a strategy to study bacterial signaling mechanisms related to bacterial cell survival, symbiosis, and virulence, and to develop sensory devices in synthetic biology. Here we focus on the principles for engineering the HK to identify unknown signal inputs, test signal transmission mechanisms, design small molecule sensors, and rewire two-component signaling networks.