title: A novel role of protein tyrosine kinase2 in mediating chloride secretion in human airway epithelial cells.
abstract: Ca(2+) activated Cl(-) channels (CaCC) are up-regulated in cystic fibrosis (CF) airway surface epithelia. The presence and functional properties of CaCC make it a possible therapeutic target to compensate for the deficiency of Cl(-) secretion in CF epithelia. CaCC is activated by an increase in cytosolic Ca(2+), which not only activates epithelial CaCCs, but also inhibits epithelial Na(+) hyperabsorption, which may also be beneficial in CF. Our previous study has shown that spiperone, a known antipsychotic drug, activates CaCCs and stimulates Cl(-) secretion in polarized human non-CF and CF airway epithelial cell monolayers in vitro, and in Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) knockout mice in vivo. Spiperone activates CaCC not by acting in its well-known role as an antagonist of either 5-HT2 or D2 receptors, but through a protein tyrosine kinase-coupled phospholipase C-dependent pathway. Moreover, spiperone independently activates CFTR through a novel mechanism. Herein, we performed a mass spectrometry analysis and identified the signaling molecule that mediates the spiperone effect in activating chloride secretion through CaCC and CFTR. Proline-rich tyrosine kinase 2 (PYK2) is a non-receptor protein tyrosine kinase, which belongs to the focal adhesion kinase family. The inhibition of PYK2 notably reduced the ability of spiperone to increase intracellular Ca(2+) and Cl(-) secretion. In conclusion, we have identified the tyrosine kinase, PYK2, as the modulator, which plays a crucial role in the activation of CaCC and CFTR by spiperone. The identification of this novel role of PYK2 reveals a new signaling pathway in human airway epithelial cells.
authors.affiliation: Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: Lihua
authors.initials: L
authors.lastname: Liang
authors.forename: Owen M
authors.initials: OM
authors.lastname: Woodward
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Chen
authors.forename: Robert
authors.initials: R
authors.lastname: Cotter
authors.forename: William B
authors.initials: WB
authors.lastname: Guggino
mesh_terms: D000818:Animals; D001980:Bronchi / Q000166:cytology*; D016466:CHO Cells; D002118:Calcium / Q000378:metabolism; D002712:Chlorides / Q000378:metabolism*; D006224:Cricetinae; D003412:Cricetulus; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000378:metabolism; D004847:Epithelial Cells / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism*; D051418:Focal Adhesion Kinase 2 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D015640:Ion Channel Gating / Q000187:drug effects; D051379:Mice; D010766:Phosphorylation / Q000187:drug effects; D019000:Phosphotyrosine / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D015203:Reproducibility of Results; D013134:Spiperone / Q000494:pharmacology; D014162:Transfection
chemical_list: D002712:Chlorides; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D049452:Green Fluorescent Proteins; D019000:Phosphotyrosine; D013134:Spiperone; D051418:Focal Adhesion Kinase 2; C103547:PTK2B protein, human; D002118:Calcium