Chemical Signal Communication between Two Protoorganelles in a Lipid-Based Artificial Cell

The chemical signal communication among organelles in the cell is extremely important for life. We demonstrate here the chemical signal communication between two protoorganelles using cascade enzyme reactions in a lipid-based artificial cell. Two protoorganelles inside the artificial cell are large unilamellar vesicles containing glucose oxidase (GOx-LUVs) and a vesicle containing horseradish peroxidase (HRP) and Amplex red, respectively. The glucose molecules outside the artificial cell penetrate the lipid bilayer through mellitin pores and enter into one protoroganelle (GOx-LUV) to produce H₂O₂, which subsequently is transported to the other protoorganelle to oxidize Amplex red into red resorufin catalyzed by HRP. The number of GOx-LUVs in an artificial cell is controlled by using a GOx-LUV solution with different density during the electroformation. The reaction rate for resorufin in the protoorganelle increases with more GOx-LUVs inside the artificial cell. The artificial cell developed here paves the way for a more complicated signal transduction mechanism study in a eukaryocyte.