Cell-based biosensors based on intein-mediated protein engineering for detection of biologically active signaling molecules

Live-cell-based biosensors have emerged as a useful tool for biotechnology and chemical biology. Genetically encoded sensor cells often use bimolecular fluorescence complementation or fluorescence resonance energy transfer to build a reporter unit that suffers from nonspecific signal activation at high concentrations. Here, we designed genetically encoded sensor cells that can report the presence of biologically active molecules via fluorescence-translocation based on split intein-mediated conditional protein trans-splicing (PTS) and conditional protein trans-cleavage (PTC) reactions. In this work, the target molecules or the external stimuli activated intein-mediated reactions, which resulted in activation of the fluorophore-conjugated signal peptide. This approach fully valued the bond-making and bond-breaking features of intein-mediated reactions in sensor construction and thus eliminated the interference of false-positive signals resulting from the mere binding of fragmented reporters. We could also a...