ABCB1 Can Actively Pump-out the Background-Free Tame Fluorescent Probe CO-1 From Live Cells

Larissa Miasiro Ciaramicoli, Heon Seok Kim, Samira Husen Alamudi, Young Tae Chang

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


Cell labelling using a small fluorescent probe is an important technique in biomedical sciences. We previously developed a biocompatible and membrane-permeable probe, CO-1, which has low nonspecific binding affinity towards nontarget molecules. Although this background-free tame probe has been utilized for labelling of various intracellular biomolecules in live cells, the probes’ backgroung-free staining mechanism was not fully understood. Here, we propose that Gating-Oriented Live-cell Distinction (GOLD) mechanism occurs when ABCB1 transporter removes unbound CO-1 molecules from mammalian cells and, in a minor role, DIRC2 pumps CO-1 out from lysosomes. We also showed that solute carrier transporters were not involved in carrying CO-1 inside of cells. The role of reporters in assisting the probes’ influx-efflux was analyzed by the combination of CRISPR library sceenings and inhibitors test. In summary, tame probe CO-1 cellular staining occurs in a dual mechanism where the probe moves freely through the cells membrane, but its washable property can be directly related to the action of ABCB1 transporter.

Original languageEnglish
Article numbere202200229
JournalChemistry - An Asian Journal
Issue number12
Publication statusPublished - 15 Jun 2022


  • ABCB1
  • background-free cell staining
  • fluorescent probe
  • Gating-Oriented Live-cell Distinction
  • Tame probe


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