Table 2.

Recent Examples of Engineered Protein-Based Sensor-Actuators

Input	Output	Engineering Starting Point	Engineering Method	Coupling Mechanism	References
fucose, lactitol, sucralose, gentiobiose	Gene regulation	LacI	Computational design, single-site saturation mutagenesis	Allostery	[41]
Vanillin	Gene regulation	QacR	Computational design	Allostery	[40]
Indole	Enzymatic activity, gene regulation, fluorescence	β-glycosidase, β-glucuronidase, cI, +5 GFP,	Rational / Computational design	Conditional stabilization	[64,65]
Digoxin, progesterone, fentanyl	Fluorescence, gene regulation, enzymatic activity	Computationally designed ligand-binding domains	Computational design / experimental optimization	Conditional stabilization	[24, 47, 48]
ABT-737	Gene regulation, CAR regulation	Bcl-xL/ABT-737 complex	Experimental selection	Conditional assembly	[81]
A1120	CAR regulation	hRBP4-Al120 complex	Experimental selection	Conditional assembly	[82]
Danoprevir, grazoprevir, asunaprevir	Gene regulation, cell signaling	NS3a-drug complexes	Computational design / experimental optimization	Conditional assembly	[84]
A1155463	CAR regulation	Bcl-xL	Computational design	Conditional assembly	[85]
Farnesyl pyrophosphate	Enzymatic activity, fluorescence, luminescence	Famesyl pyrophosphate binding motif & library of >1000 protein-protein scaffolds	Computational design / structure-guided design	Conditional assembly	[31]