Nedd4-2 does not regulate wt-CFTR in human airway epithelial cells.
The cystic fibrosis transmembrane conductance regulator (CFTR), a Cl(-) channel in airway epithelial cells, plays an important role in maintaining the volume of the airway surface liquid and therefore mucociliary clearance of respiratory pathogens. A recent study has shown that the E3 ubiquitin ligase Neural precursor cells expressed developmentally downregulated (Nedd4-2) ubiquitinates ΔF508-CFTR in pancreatic epithelial cells and that siRNA-mediated silencing of Nedd4-2 increases plasma membrane ΔF508-CFTR. Because the role of Nedd4-2 in regulating wild-type (wt)-CFTR in airway epithelial cells is unknown, studies were conducted to test the hypothesis that Nedd4-2 also ubiquitinates wt-CFTR and regulates its plasma membrane abundance. We found that Nedd4-2 did not affect wt-CFTR Cl(-) currents in Xenopus oocytes. Likewise, overexpression of Nedd4-2 in human airway epithelial cells did not alter the amount of ubiquitinated wt-CFTR. siRNA knockdown of Nedd4-2 in human airway epithelial cells had no effect on ubiquitination or apical plasma membrane abundance of wt-CFTR. Thus Nedd4-2 does not ubiquitinate and thereby regulate wt-CFTR in human airway epithelial cells.
Department of Microbiology and Immunology, The Geisel School of Medicine at Dartmouth, 604 Remsen, Hanover, NH 03755, USA. Katja.Koeppen@Dartmouth.edu
Katja
K
Koeppen
Chris
C
Chapline
J Denry
JD
Sato
Bruce A
BA
Stanton
D000818:Animals; D017920:Antiporters / Q000378:metabolism; D001980:Bronchi / Q000166:cytology; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D002712:Chlorides / Q000378:metabolism; D003550:Cystic Fibrosis / Q000378:metabolism; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics / Q000378:metabolism*; D056827:Endosomal Sorting Complexes Required for Transport / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008564:Membrane Potentials / Q000502:physiology; D000075702:Nedd4 Ubiquitin Protein Ligases; D009865:Oocytes / Q000502:physiology; D010750:Phosphoproteins / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D020545:Respiratory Mucosa / Q000166:cytology* / Q000378:metabolism*; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism; D000076988:Sulfate Transporters; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*; D054875:Ubiquitination / Q000502:physiology; D014981:Xenopus; D029867:Xenopus Proteins
D017920:Antiporters; C505032:CFTR protein, human; D002712:Chlorides; D056827:Endosomal Sorting Complexes Required for Transport; D010750:Phosphoproteins; D034741:RNA, Small Interfering; C455628:SLC26A9 protein, human; D017923:Sodium-Hydrogen Exchangers; D000076988:Sulfate Transporters; D029867:Xenopus Proteins; C093376:sodium-hydrogen exchanger regulatory factor; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D000075702:Nedd4 Ubiquitin Protein Ligases; C000618482:Nedd4 protein, Xenopus; C000618483:Nedd4 protein, human; C000618485:Nedd4L protein, human; C000618460:nedd4l protein, Xenopus; D044767:Ubiquitin-Protein Ligases