CFTR in a lipid raft-TNFR1 complex modulates gap junctional intercellular communication and IL-8 secretion.
Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) cause a chronic inflammatory response in the lung of patients with Cystic Fibrosis (CF). We have showed that TNF-alpha signaling through the Src family tyrosine kinases (SFKs) was defective as determined by an inability of TNF-alpha to regulate gap junctional communication (GJIC) in CF cells. Here, we sought to elucidate the mechanisms linking TNF-alpha signaling to the functions of CFTR at the molecular level. In a MDCKI epithelial cell model expressing wild-type (WtCFTR) or mutant CFTR lacking its PDZ-interacting motif (CFTR-DeltaTRL), TNF-alpha increased the amount of WtCFTR but not CFTR-DeltaTRL in detergent-resistant membrane microdomains (DRMs). This recruitment was modulated by SFK activity and associated with DRM localization of TNFR1 and c-Src. Activation of TNFR1 signaling also decreased GJIC and markedly stimulated IL-8 production in WtCFTR cells. In contrast, the absence of CFTR in DRMs was associated with abnormal TNFR1 signaling as revealed by no recruitment of TNFR1 and c-Src to lipid rafts in CFTR-DeltaTRL cells and loss of regulation of GJIC and IL-8 secretion. These results suggest that localization of CFTR in lipid rafts in association with c-Src and TNFR1 provides a responsive signaling complex to regulate GJIC and cytokine signaling.
Dudez
Tecla
T
Laboratory of Clinical Investigation III, Micheli-du-Crest, Geneva, Switzerland.
Borot
Florence
F
Huang
Song
S
Kwak
Brenda R
BR
Bacchetta
Marc
M
Ollero
Mario
M
Stanton
Bruce A
BA
Chanson
Marc
M
D000818:Animals; D002450:Cell Communication; D002460:Cell Line; D018031:Connexin 43 / Q000032:analysis; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D004285:Dogs; D017629:Gap Junctions / Q000378:metabolism*; D016209:Interleukin-8 / Q000378:metabolism*; D021962:Membrane Microdomains / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D008565:Membrane Proteins / Q000032:analysis; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000378:metabolism; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000378:metabolism*; D017384:Sequence Deletion; D015398:Signal Transduction; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D019061:src-Family Kinases / Q000378:metabolism
D018031:Connexin 43; D016209:Interleukin-8; D008565:Membrane Proteins; D047888:Receptors, Tumor Necrosis Factor, Type I; D014409:Tumor Necrosis Factor-alpha; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D016392:Proto-Oncogene Proteins pp60(c-src); D019061:src-Family Kinases