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Analysis of Protein Folding, Transport, and Degradation in Living Cells by Radioactive Pulse Chase
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Mechanisms for rescue of correctable folding defects in CFTRDelta F508

Diane E Grove1, Meredith F N Rosser, Hong Yu Ren

  • 1Department of Cell and Developmental Biology and the UNC-Cystic Fibrosis Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.

Molecular Biology of the Cell
|July 24, 2009
PubMed

Insights

Inactivating RMA1 or CHIP ubiquitin ligases helps cystic fibrosis (CF) transmembrane conductance regulator (CFTR)DeltaF508 folding. Combining these with correctors enhances CFTR folding, offering a potential therapeutic strategy for CF.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Genetics

Background:

  • Cystic Fibrosis (CF) is caused by premature degradation of the CFTRDeltaF508 protein.
  • Folding correctors are investigated as therapeutics, but the cellular environment's impact on CFTRDeltaF508 folding efficiency remains unclear.

Purpose of the Study:

  • To investigate how cellular environment modulation affects CFTRDeltaF508 folding.
  • To identify correctable folding defects in CFTRDeltaF508.

Main Methods:

  • Inactivation of RMA1 or CHIP ubiquitin ligases.
  • Treatment with the folding corrector Corr-4a.
  • Analysis of CFTRDeltaF508 folding efficiency and localization.

Main Results:

  • RMA1 or CHIP inactivation allowed CFTRDeltaF508 to escape endoplasmic reticulum retention.
  • Combined inactivation and Corr-4a treatment enhanced CFTRDeltaF508 folding 3-7 fold compared to Corr-4a alone.
  • RMA1 and CHIP recognize different CFTR regions, with RMA1 acting on nascent CFTRDeltaF508.

Conclusions:

  • Modulating ER quality control by inactivating RMA1/CHIP can significantly improve CFTRDeltaF508 folding.
  • Some, but not all, folding defects are correctable, suggesting targeted therapeutic approaches.
  • This strategy holds potential for developing new CF therapies.

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