Zabłocki K, Waśniewska M, Duszyński J
Department of Cellular Biochemistry, Nencki Institute of Experimental Biology, Warszawa, Poland.
Acta Biochim Pol. 2000;47(3):591-9.
The participation of phospholipase A2 isoforms in capacitative store-operated Ca2+ influx into Jurkat leukemic T and MDCK cells was investigated. Preincubation of Jurkat cells with either bromophenacyl bromide (an inhibitor of secreted phospholipase A2, sPLA2) or Helss (an inhibitor of calcium independent phospholipase A2--iPLA2) resulted in a significant inhibition of the calcium influx. The extent of this inhibition depended on the pH of the extracellular millieu; it increased with alkalisation. The rate of Ca2+ influx into MDCK cells was reduced by bromophenacyl bromide. Preincubation of these cells with Helss resulted in the stimulation of the influx. These observations suggest the participation of different PLA2 isoforms in the regulation of Ca2+ influx. They also show that the extent that PLA2 isoforms control the influx depends on the pH of the medium. Finally, these data indicate that various phospholipase A2 isoforms may play a role in the control of Ca2+ influx in different cell lines.
研究了磷脂酶A2同工型在调节Ca2+流入Jurkat白血病T细胞和MDCK细胞的钙库操纵性Ca2+内流过程中的作用。用溴苯甲酰溴（一种分泌型磷脂酶A2，即sPLA2的抑制剂）或Helss（一种钙非依赖性磷脂酶A2，即iPLA2的抑制剂）对Jurkat细胞进行预孵育，可显著抑制Ca2+内流。这种抑制程度取决于细胞外环境的pH值；随着碱化程度增加而增强。溴苯甲酰溴可降低Ca2+流入MDCK细胞的速率。用Helss对这些细胞进行预孵育则会刺激Ca2+内流。这些观察结果表明不同的PLA2同工型参与了Ca2+内流的调节。它们还表明PLA2同工型控制Ca2+内流的程度取决于培养基的pH值。最后，这些数据表明各种磷脂酶A2同工型可能在不同细胞系中Ca2+内流的控制中发挥作用。
