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Guanine nucleotide exchange factors regulate epithelial sodium channel (ENaC) activity in alveolar epithelial cells
Author(s) -
Trac David,
Goodson Preston,
Kumar Amrita,
Helms My N.
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.1039.35
Subject(s) - epithelial sodium channel , microbiology and biotechnology , chemistry , guanine nucleotide exchange factor , nadph oxidase , reabsorption , superoxide , reactive oxygen species , signal transduction , sodium , biology , biochemistry , enzyme , organic chemistry
Epithelial sodium channels (ENaC) in the lung transport Na + ions from luminal to basolateral airway surfaces, and hence, create the osmotic driving force for water reabsorption in the lung. While we have shown that reactive oxygen species (ROS) regulate ENaC activity, the signaling mechanisms that control ROS generation in these cells remain unknown. Our results show that NADPH oxidase (NOX) 2 catalyzes the release of superoxide and that the small G protein, Rac1, is an important regulator of NOX2 in all cells that make up the alveolar epithelium (type 1 and type 2). The objective of this study is to identify the Rac‐activating guanine exchange factors (GEF) that mediate assembly of the NOX2 enzymatic complex in alveolar epithelial cells. Using a flow cytometric approach for isolating pure populations of type 1 and type 2 cells, and real‐time PCR, we characterize the mRNA expression level of five GEFs: Arhgrf7, Sos1, Tiam2, Tiam1, and Ras‐GRF2 in alveolar epithelial cells. Our findings identify the GEFs that may be important regulators of both ROS production and ENaC activity in the lung.