Endocytic Sorting of CFTR Variants Monitored by Single-Cell Fluorescence Ratiometric Image Analysis (FRIA) in Living Cells

  • Herve Barrière
  • Pirjo Apaja
  • Tsukasa Okiyoneda
  • Gergely L. LukacsEmail author
Part of the Methods in Molecular Biology book series (MIMB, volume 741)


The wild-type CFTR channel undergoes constitutive internalization and recycling at the plasma membrane. This process is initiated by the recognition of the Tyr- and di-Leu-based endocytic motifs of CFTR by the AP-2 adaptor complex, leading to the formation of clathrin-coated vesicles and the channel delivery to sorting/recycling endosomes. Accumulating evidence suggests that conformationally defective mutant CFTRs (e.g. rescued F508del and glycosylation-deficient channel) are unstable at the plasma membrane and undergo augmented ubiquitination in post-Golgi compartments. Ubiquitination conceivably accounts for the metabolic instability at cell surface by provoking accelerated internalization, as well as rerouting the channel from recycling towards lysosomal degradation. We developed an in vivo fluorescence ratiometric image analysis (FRIA) that in concert with genetic manipulation can be utilized to establish the post-endocytic fate and sorting determinants of mutant CFTRs.

Key words

CF mutations conformational defect endosomal sorting recycling lysosomal targeting ubiquitin-binding protein plasma membrane ESCRT vesicular pH siRNA 


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Copyright information

© Springer Science+Business Media, LLC 2011

Authors and Affiliations

  • Herve Barrière
    • 1
  • Pirjo Apaja
    • 1
  • Tsukasa Okiyoneda
    • 1
  • Gergely L. Lukacs
    • 1
    Email author
  1. 1.Department of PhysiologyMcGill UniversityMontréalCanada

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