Association of cystic fibrosis transmembrane conductance regulator with epithelial sodium channel subunits carrying Liddle's syndrome mutations.
Arun K RoojEstelle Cormet-BoyakaEdlira B ClarkYawar J QadriWilliam LeeRavindra BodduAnupam AgarwalRicha TambiMohammed UddinVladimir ParpuraEric J SorscherCathy M FullerBakhrom K BerdievPublished in: American journal of physiology. Lung cellular and molecular physiology (2021)
The association of the cystic fibrosis transmembrane conductance regulator (CFTR) and epithelial sodium channel (ENaC) in the pathophysiology of cystic fibrosis (CF) is controversial. Previously, we demonstrated a close physical association between wild-type (WT) CFTR and WT ENaC. We have also shown that the F508del CFTR fails to associate with ENaC unless the mutant protein is rescued pharmacologically or by low temperature. In this study, we present the evidence for a direct physical association between WT CFTR and ENaC subunits carrying Liddle's syndrome mutations. We show that all three ENaC subunits bearing Liddle's syndrome mutations (both point mutations and the complete truncation of the carboxy terminus), could be coimmunoprecipitated with WT CFTR. The biochemical studies were complemented by fluorescence lifetime imaging microscopy (FLIM), a distance-dependent approach that monitors protein-protein interactions between fluorescently labeled molecules. Our measurements revealed significantly increased fluorescence resonance energy transfer between CFTR and all tested ENaC combinations as compared with controls (ECFP and EYFP cotransfected cells). Our findings are consistent with the notion that CFTR and ENaC are within reach of each other even in the setting of Liddle's syndrome mutations, suggestive of a direct intermolecular interaction between these two proteins.
Keyphrases
- cystic fibrosis
- energy transfer
- pseudomonas aeruginosa
- lung function
- protein protein
- wild type
- case report
- quantum dots
- single molecule
- small molecule
- high resolution
- mental health
- physical activity
- transcription factor
- induced apoptosis
- oxidative stress
- mass spectrometry
- binding protein
- signaling pathway
- high speed
- positron emission tomography
- endoplasmic reticulum stress