Genistein inhibits Ca2+ influx by extracellular ATP in PC12 pheochromocytoma cells.
We previously showed that extracellular ATP-induced Ca2+ influx is inhibited by self-activated protein kinase C in rat PC12 pheochromocytoma cells. In the present study, we examined whether tyrosine kinase is involved in the ATP-induced Ca2+ influx in PC12 cells. Genistein, an inhibitor of protein tyrosine kinases, which by itself had little effect on 45Ca2+ influx, significantly suppressed the ATP-induced 45Ca2+ influx in a dose-dependent manner in the range between 1 and 30 micrograms/ml. Tyrophostin, another inhibitor of tyrosine kinases chemically distinct from genistein, also inhibited the 45Ca2+ influx. Sodium orthovanadate, an inhibitor of protein tyrosine phosphatases, markedly enhanced the ATP-induced 45Ca2+ influx. These results suggest that tyrosine kinase regulates Ca2+ influx induced by extracellular ATP in PC12 pheochromocytoma cells.
Kozawa
O
O
Department of Biochemistry, Institute for Development Research, Aichi, Japan.
Shinoda
J
J
Suzuki
A
A
D000255:Adenosine Triphosphate / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002132:Calcium Radioisotopes; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D019833:Genistein; D007529:Isoflavones / Q000494:pharmacology*; D016716:PC12 Cells; D017027:Protein Tyrosine Phosphatases / Q000037:antagonists & inhibitors; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D051381:Rats; D014638:Vanadates / Q000494:pharmacology
D002132:Calcium Radioisotopes; D004791:Enzyme Inhibitors; D007529:Isoflavones; D014638:Vanadates; D000255:Adenosine Triphosphate; D019833:Genistein; D011505:Protein-Tyrosine Kinases; D017027:Protein Tyrosine Phosphatases; D002118:Calcium