Genetically Targeted Ratiometric and Activated pH Indicator Complexes (TRApHIC) for Receptor Trafficking

Biochemistry. 2018 Feb 6;57(5):861-871. doi: 10.1021/acs.biochem.7b01135. Epub 2018 Jan 16.

Abstract

Fluorescent protein-based pH sensors are useful tools for measuring protein trafficking through pH changes associated with endo- and exocytosis. However, commonly used pH-sensing probes are ubiquitously expressed with their protein of interest throughout the cell, hindering our ability to focus on specific trafficking pools of proteins. We developed a family of excitation ratiometric, activatable pH responsive tandem dyes, consisting of a pH sensitive Cy3 donor linked to a fluorogenic malachite green acceptor. These cell-excluded dyes are targeted and activated upon binding to a genetically expressed fluorogen-activating protein and are suitable for selective labeling of surface proteins for analysis of endocytosis and recycling in live cells using both confocal and superresolution microscopy. Quantitative profiling of the endocytosis and recycling of tagged β2-adrenergic receptor (B2AR) at a single-vesicle level revealed differences among B2AR agonists, consistent with more detailed pharmacological profiling.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Carbocyanines / analysis*
  • Coloring Agents / analysis*
  • Endocytosis / physiology*
  • Endosomes / metabolism
  • Endosomes / ultrastructure
  • Exocytosis / physiology*
  • Fluorescent Dyes / analysis*
  • HEK293 Cells
  • Humans
  • Hydrogen-Ion Concentration
  • Indicators and Reagents / analysis
  • Microscopy, Confocal
  • Protein Transport / physiology*
  • Receptors, Adrenergic, beta-2 / metabolism
  • Rosaniline Dyes / analysis*
  • Single-Chain Antibodies / analysis*

Substances

  • Carbocyanines
  • Coloring Agents
  • Fluorescent Dyes
  • Indicators and Reagents
  • Receptors, Adrenergic, beta-2
  • Rosaniline Dyes
  • Single-Chain Antibodies
  • cyanine dye 3
  • malachite green