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Investigation of the Sodium‐Hydrogen Exchanger 1 and Calcineurin Homologous Protein Isoforms 1 and 2 interaction in Lung Fibroblasts
Author(s) -
PolveroniEdwards Thomas,
Wallert Mark,
Provost Joseph John
Publication year - 2016
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.30.1_supplement.1108.6
Subject(s) - sodium–hydrogen antiporter , microbiology and biotechnology , chemistry , intracellular ph , gene isoform , cytosol , intracellular , biochemistry , biology , sodium , enzyme , gene , organic chemistry
The Sodium‐Hydrogen Exchanger 1 (NHE1) is a transmembrane protein that plays a crucial role in maintaining stable intracellular pH. Furthermore, the protein is regulated by interaction between the C‐terminus of NHE1 and several intracellular proteins, including Calcineurin Homologous Protein Isoform 1 (CHP1) and 2 (CHP2). NHE1's role and importance are easily observable in metastatic lung cancer cells as the exchanger displays higher than normal activity in order to compensate for the increased metabolism and proton production found in the metabolically active cells. Expression of CHP1 to NHE1 is ubiquitous and CHP1‐NHE1 interaction is necessary for proper function of the exchanger, whereas the expression of CHP2 to NHE1 has so far only been found in gut cells and metastatic cancer cells. To investigate the differences between CHP1 and CHP2, and their binding to NHE1, we prepared CHP1‐RFP and CHP2‐GFP and observed their expression in Chinese Hamster Lung Fibroblasts with NHE1 null expressors (PS120 cells) and in Chinese Hamster Lung Fibroblasts stably expressing human NHE1 (PSN cells). Substantial translocation of CHP1 and CHP2 to the cellular membrane was observed in the PSN cells whereas no translocation was observed in the PS120 cells. We also generated several single amino acid alterations of NHE1 to determine the importantance of these residues on binding. Furthermore expression and translocation levels were also measured in fed, serum deprived and stimulated conditions.