Chemical strategies for tagging and imaging the proteome

Proteomic visualization serves as a complement to proteomic identification. In recent years, chemical biologists have made rapid progress developing new methods to tag and image defined sets of proteins. These researchers have requisitioned cellular machinery to place small, reactive analogues into biomolecules. The analogue has been labeled subsequently using a selective ligation reaction. Many groups have demonstrated the efficacy of the copper-catalyzed or strain-promoted azide-alkyne ligation; both enable rapid and precise labeling in complex biological mixtures. This review provides an overview of the methods which have been optimized to tag and fluorophore-label biomolecules for imaging subsets of the proteome in bacterial and mammalian cells. With the approaches described herein, it should be possible to image cells as they undergo changes over time.