| The development and metastasis of tumors are closely related to their microenvironments(TME,tumor microenviroment).Therefore,it is extremely important to have a better understanding of the interactions between the tumor cells and their microenvironments.PUP-IT system is a proximity-labeling system.In this system,the bait protein is fused to the proteasome accessory factor A(Paf A).Under the catalysis of Paf A,the bait and its proximity proteins,such as the prey,could be labeled by the deaminated prokaryotic ubiquitin-like protein(Pup)at the lysine residues.Based on the PUP-IT system,we designed a proximity sensor to study cell-cell interactions.With the catalysis of Paf A,Pup(E)can be labeled on the nearby cells by cells transfected with the plasmid encoding the PUP-IT sensor.Our results showed that this proximity sensor could be used in self-labeling and proximity-labeling of cells.Our proximity sensor could be used in the future studies to investigate the interactions between tumor cells and their microenvironments.Protein-protein interactions play essential roles in the life of cells.Clearly indentifying protein-protein interactions and delineating their interaction network are important for understanding the biology of cell.Currently,many methods had been developed to study protein-protein interactions.However,each of them had its own advantages and limitations.We fused prey and bait to the two halves of ubiquitin,respectively.It two proteins have interaction,the two halves of ubiquitin will be reconstituted and Cre will be released to the nucleus and mediate recombinations.Based on it,we designed two proximity sensors to study protein-protein interactions at intracellular or extracellular space,respectively.However,our preliminary results indicated that both sensors could not be used to effectively detect protein-protein interactions.Therefore,further studies are required to optimize the sensors for application in the study of protein-protein interactions. |
