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The Effect of Proline Rich Tyrosine Kinase 2 Activity on the Na + ‐H + Exchanger Isoform 1 Regulation of Cell Proliferation and Migration
Author(s) -
Bagnell Kyle P,
Provost Joseph J,
Wallert Mark A.
Publication year - 2017
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.31.1_supplement.614.29
Subject(s) - phosphorylation , kinase , microbiology and biotechnology , sodium–hydrogen antiporter , chemistry , tyrosine phosphorylation , serine , tyrosine kinase , cell growth , biology , signal transduction , biochemistry , sodium , organic chemistry
The Na + ‐H + exchanger isoform 1 (NHE1) is a 12‐pass transmembrane protein that functions by exchanging one extracellular sodium ion for one intracellular proton. The transmembrane domain of NHE1 is involved in ion exchange, and the cytoplasmic tail is the regulatory domain where various kinase and proteins bind, altering transport activity. NHE1 is a central driver of the hallmarks of cancer through its involvement in driving cellular proliferation, migration, and invasion. While the exact number of phosphorylation sites on the cytoplasmic domain of NHE1 is still unclear, many studies have implicated 22 phosphorylation sites and 12 different kinases. One of the kinases believed to directly or indirectly lead to the phosphorylation of NHE1 at S602/S605 is proline rich tyrosine kinase 2 (PyK2). To evaluate the role of PyK2 in NHE1 regulation we prepared three cell lines derived from Chinese hamster lung fibroblast lacking NHE1 expression (PS120 cells). These cell lines are PSN (PS120 cells expressing human NHE1), PSN S602A/S605A (PSN cells with serine to alanine mutations of the reported PyK2 phosphorylation sites) and PSN S602D/S605D (PSN cells with serine to aspartic acid mutations of the reported PyK2 phosphorylation sites to mimic phosphorylation). Some studies have found that PyK2 works inversely on NHE1 and causes inhibition upon activation, while other studies have shown PyK2 to enhance NHE1 activity. In PSN cells stimulated with LPA, it has been shown that inhibition of PyK2 increases the LPA induced increase in pHi. Here we evaluate the impact of PyK2 inhibition and mutation of the PyK2 phosphorylation sites on proliferation and migration. Our results suggest that serum stimulation enhances cell proliferation and PF43I396 inhibition of PyK2 in serum stimulated cells decreases proliferation rate. To further evaluate these responses we will evaluate PSN and PyK2 mutant cells for proliferation and migration stimulated by serum and LPA.