Effects of nonselective cation channels and PI3K on endothelin-1-induced PYK2 tyrosine phosphorylation in C6 glioma cells.
We recently demonstrated that endothelin-1 (ET-1) activates two types of Ca2+-permeable nonselective cation channels (designated NSCC-1 and NSCC-2) in C6 glioma cells. In the present study, we investigated the effects of NSCCs on the ET-1-induced proline-rich tyrosine kinase 2 (PYK2) phosphorylation in C6 glioma cells. In addition, we examined the effects of phosphoinositide 3-kinase (PI3K) on the ET-1-induced NSCCs activation and PYK2 phosphorylation. The PI3K inhibitors wortmannin and LY-294002 inhibited ET-1-induced Ca2+ influx through NSCC-2 but not NSCC-1. On the other hand, addition of these inhibitors after stimulation with ET-1 failed to suppress Ca2+ influx through NSCC-2. PYK2 phosphorylation was abolished by blocking Ca2+ influx through NSCCs. The PI3K inhibitors blocked the NSCC-2-dependent part of ET-1-induced PYK2 phosphorylation. These results indicate that 1) NSCC-2 is stimulated by ET-1 via a PI3K-dependent cascade, whereas NSCC-1 is stimulated via a PI3K-independent cascade; 2) PI3K seems to be required for the activation of the Ca2+ entry, but not for its maintenance; 3) Ca2+ influx through NSCC-1 and NSCC-2 plays an essential role in ET-1-induced PYK2 phosphorylation; and 4) PI3K is involved in the ET-1-induced PYK2 phosphorylation that depends on the Ca2+ influx through NSCC-2.
Kawanabe
Yoshifumi
Y
Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kapan. ykawanabe@rics.bwh.harvard.edu
Hashimoto
Nobuo
N
Masaki
Tomoh
T
D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000378:metabolism; D002412:Cations / Q000378:metabolism; D002455:Cell Division / Q000502:physiology; D002867:Chromones / Q000494:pharmacology; D019332:Endothelin-1 / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D051418:Focal Adhesion Kinase 2; D005910:Glioma; D007093:Imidazoles / Q000494:pharmacology; D053496:Inositol 1,4,5-Trisphosphate Receptors; D007473:Ion Channels / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009025:Morpholines / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation / Q000187:drug effects; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D051381:Rats; D018160:Receptors, Cytoplasmic and Nuclear / Q000037:antagonists & inhibitors / Q000378:metabolism; D014407:Tumor Cells, Cultured; D000077191:Wortmannin
D000730:Androstadienes; D002118:Calcium; D002121:Calcium Channel Blockers; D015220:Calcium Channels; D002412:Cations; D002867:Chromones; D019332:Endothelin-1; D004791:Enzyme Inhibitors; D051418:Focal Adhesion Kinase 2; D007093:Imidazoles; D053496:Inositol 1,4,5-Trisphosphate Receptors; D007473:Ion Channels; D009025:Morpholines; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011505:Protein-Tyrosine Kinases; D018160:Receptors, Cytoplasmic and Nuclear; D000077191:Wortmannin; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C496054:Ptk2b protein, rat; C063159:1-(2-(3-(4-methoxyphenyl)propoxy)-4-methoxyphenylethyl)-1H-imidazole