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Sphingosine‐1‐Phosphate acutely modulates the Cystic Fibrosis Transmembrane Conductance Regulator Protein in an S1P2 and AMPK‐dependent manner
Author(s) -
Malik Firhan Atir,
Meissner Anja,
Bear Christine,
Bolz Steffen Sebastian
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.746.6
Subject(s) - ampk , sphingosine 1 phosphate , cystic fibrosis transmembrane conductance regulator , regulator , cystic fibrosis , transmembrane protein , microbiology and biotechnology , chemistry , conductance , sphingosine , medicine , biochemistry , biology , protein kinase a , phosphorylation , receptor , physics , gene , condensed matter physics
Sphingosine‐1‐phosphate's (S1P) degradation, a ubiquitous signaling mediator directing diverse biological processes, is controlled by S1P phosphohydrolases (SPP1). The intracellular localization of SPP1 requires the import of extracellular S1P prior to its degradation, a step we found to be controlled by CFTR. We hypothesize S1P regulates CFTR function and its own degradation in an AMPK‐dependent manner. CFTR conductance was assessed using iodide efflux techniques (conventional and real‐time) in baby hamster kidney cells that stably express WT‐hCFTR and endogenously express S1P‐signalling components (e.g., S1P 2 R). CFTR expression and phosphorylation were determined using Western blots, and its subcellular localization was assessed with fluorescence microscopy. S1P significantly reduced (n=6, p<0.05) iodide conductance by 43% (conventional) and 75% (real‐time). The inhibiting effect on iodide conductance was reduced by the S1P 2 blocker JTE013 (n=6), and was associated with the AMP‐dependent kinase (AMPK); compound C (n=5), an AMPK inhibitor, abolished the effects of S1P. S1P treatment reduced CFTR's Band C:B ratio by 76±1.2%, and CFTR's membrane fluorescence by 77±3.9% (n=3). Finally, binding of non‐phospho‐CFTR specific antibody was reduced by 42±6.1% and 65±0.92% (n=3) following 30s and 1h S1P treatments respectively. The S1P2R‐ and AMPK‐dependent modulation of CFTR conductance characterizes a novel pathway that potentially allows S1P to regulate its own degradation.