Izquierdo M, Ruiz-Ruiz M C, López-Rivas A
Institute of Parasitology and Biomedicine, Granada, Spain.
J Immunol. 1996 Jul 1;157(1):21-8.
We have analyzed the requirements for activation-induced apoptosis in Jurkat T cells expressing the heterologous human muscarinic type 1 receptor (HM1R; J-HM1-2.2 cells) that is coupled to phosphatidylinositol turnover through a protein tyrosine kinase-independent, G protein-regulated mechanism. Triggering of HM1R with the agonist carbachol is sufficient to induce apoptosis in J-HM1-2.2 cells. Apoptosis is also induced in J-HM1-2.2 cells by triggering of the TCR. Calcium influx, intracellular Ca2+ increase, calcineurin function, and de novo protein synthesis are necessary for receptor-controlled apoptosis. However, blocking protein kinase C with a specific inhibitor does not abrogate receptor-induced apoptosis. Furthermore, HM1R-induced apoptosis is inhibited by blocking Fas ligand/Fas interaction with an antagonist anti-Fas Ab, and Fas ligand mRNA and protein are expressed in J-HM1-2.2 cells stimulated through the HM1R. Therefore, protein tyrosine kinase activation is not an absolute requirement for receptor-controlled Fas ligand expression. Taken together, the results demonstrate that stimulation of phosphatidylinositol turnover can induce apoptosis through a Fas-dependent mechanism that requires calcineurin stimulation, but not protein kinase C activation.
我们分析了表达通过蛋白酪氨酸激酶非依赖性、G蛋白调节机制与磷脂酰肌醇代谢偶联的异源人M1型毒蕈碱受体（HM1R；J-HM1-2.2细胞）的Jurkat T细胞中激活诱导凋亡的需求。用激动剂卡巴胆碱触发HM1R足以在J-HM1-2.2细胞中诱导凋亡。通过触发TCR也可在J-HM1-2.2细胞中诱导凋亡。钙内流、细胞内Ca2+增加、钙调神经磷酸酶功能和从头蛋白质合成对于受体控制的凋亡是必需的。然而，用特异性抑制剂阻断蛋白激酶C并不能消除受体诱导的凋亡。此外，通过用拮抗剂抗Fas抗体阻断Fas配体/Fas相互作用可抑制HM1R诱导的凋亡，并且在通过HM1R刺激的J-HM1-2.2细胞中表达Fas配体mRNA和蛋白。因此，蛋白酪氨酸激酶激活对于受体控制的Fas配体表达不是绝对必需的。综上所述，结果表明磷脂酰肌醇代谢的刺激可通过一种需要钙调神经磷酸酶刺激但不需要蛋白激酶C激活的Fas依赖性机制诱导凋亡。
