Construction Of Light-sensing Two Component Systems In Escherichia Coli

Two component systems(TCSs)are the prevalent mode of signal transduction for bacteria.A TCS consists of two components,a sensor histidine kinase(HK)and a response regulator(RR).The sensor HK belongs to transmembrane protein that can sense environmental signals and transfer the signal to the cognate RR after being autophosphorylated.The activated RR regulates downstream gene expression by binding to the specific promoter sequences.The variety of extracellular signals complicates the attempt for systematical TCSs study,which is time and labor consuming.Here,we adopt an optogenetics approach to investigate TCSs by reengineering the sensor HKs as a light-sensing fusion protein,so that the study of TCSs can be achieved in a unified way by simulating extracellular signals with light.We construct a two-vector system to screen for light-sensing HKs.Using this system,we screen and obtain light-sensing HKs for eight dif-ferent TCSs(UhpB-UhpA,PhoR-PhoB,YedV-YedW,RstB-RstA,GlrK-GlrR,CusS-CusR,PhoQ-PhoP and CpxA-CpxR).As an application,we investigate the characteristics of the UhpB-UhpA system from the view of signal processing and show that it is a low-pass filter that favors signals with low frequency.Our work demonstrates the advantage of light-controllable HKs for the study of TCSs and set the foundation for future systematic study for TCSs.