Live-cell protein labeling using a protein tag and a fluorescent probe is a powerful approach for studying protein localization and dynamics. Herein, we engineered a protein tag, PYP-tag, to image membrane proteins with high contrast. Mutations of charged amino acids on the surface of PYP-tag led to the enhancement of labeling kinetics and brightness. Furthermore, the modification of the surface charge did not affect its expression on the cell surface, and we succeeded in applying this labeling technique to high-contrast imaging of translocation of glucose transporter 4.