Quantitative Multi-color Detection Strategies for Bioorthogonally Labeled GPCRs

  • Minyoung Park
  • He Tian
  • Saranga Naganathan
  • Thomas P. Sakmar
  • Thomas Huber
Part of the Methods in Molecular Biology book series (MIMB, volume 1335)


We describe multiple bioorthogonal approaches to label G protein-coupled receptors (GPCRs) heterologously expressed in mammalian cells. The use of genetically encoded unnatural amino acids as bioorthogonal tags results in receptors that are expressed at lower levels than even their low abundance wild-type counterparts. Therefore, reproducible and sensitive quantification of the labeled GPCRs is extremely important and conventional methods are simply not sufficiently accurate and precise. Silver stains lack reproducibility, spectroscopic methods using fluorescent ligands are limited to quantifying only functional receptor molecules, and immunoassays using epitope tags derived from rhodopsin are particularly variable for low-abundance GPCRs. To avoid these shortcomings, we employ near infrared (NIR) imaging-based methods that enable simultaneous multi-color detection of two different antigens, thus facilitating the ratiometric analysis of bioorthogonally modified GPCRs. We anticipate that these multi-color detection strategies will provide new tools for quantitatively assessing stoichiometrically labeled GPCRs for studies of signalosomes and for structure–function relationships at a single molecule level.

Key words

G protein-coupled receptor Bioorthogonal labeling SpAAC LI-COR Near infrared-based detection Quantitative analysis 



This work was supported by the Danica Foundation, the Crowley Family Fund, and an International Research Alliance at the Novo Nordisk Foundation Center for Basic Metabolic Research through an unconditional grant from the Novo Nordisk Foundation to the University of Copenhagen. H. T. was funded by the Tri-Institutional Program in Chemical Biology. We thank the Rockefeller University Proteomics Resource Center for peptide synthesis.


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Copyright information

© Springer Science+Business Media New York 2015

Authors and Affiliations

  • Minyoung Park
    • 1
  • He Tian
    • 1
  • Saranga Naganathan
    • 1
  • Thomas P. Sakmar
    • 1
    • 2
  • Thomas Huber
    • 1
  1. 1.Laboratory of Chemical Biology & Signal TransductionThe Rockefeller UniversityNew YorkUSA
  2. 2.Department of Neurobiology, Care Sciences and Society, Division for Neurogeriatrics, Center for Alzheimer ResearchKarolinska InstitutetHuddingeSweden

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