Abstract
[Image: see text] A nuclear protein target, polo-like kinase 1 (PLK1) was imaged using a biocompatible bioorthogonal ligation between a specific drug and a fluorescent dye in live cells. Colocalization of the dye and the protein target was confirmed by antibody staining and by expressing a GFP construct of PLK1. The two-step PLK1 imaging procedure was used to quantify PLK1 expression levels in cancer cell lines of various tissue origins.