Tools for protein trafficking

The endocytic/exocytic processes are fundamental to a wide range of biological phenomena, including immunity, allergy and synaptic transmission. Utilizing engineered proteins that fold well in the secretory pathway of cells and bind to otherwise weakly fluorescent dye molecules, we have developed a series of fluorescent pH indicators that are “activated by targeting.” These ratiometric dyes enable direct interrogation of the endocytic trafficking process and the protein fate after stimulation by biological ligands or drugs. Trafficking of receptors and transporters under the influence of genetic mutations and pharmacologic treatments provides new mechanistic and therapeutic insights into these important biological processes.