Stewart S J, Cunningham G R, Strupp J A, House F S, Kelley L L, Henderson G S, Exton J H, Bocckino S B
Department of Medicine, Howard Hughes Medical Institute Vanderbilt University School of Medicine, Nashville, Tennessee.
Cell Regul. 1991 Oct;2(10):841-50. doi: 10.1091/mbc.2.10.841.
A number of cellular signaling systems are called into play by interaction of the T lymphocyte antigen receptor/CD3 complex with its cognate antigen. Well-described signaling systems include phosphoinositide turnover, tyrosine phosphorylation, protein kinase C activation, and increased cytosolic calcium. We have explored the possibility that another recently described signaling system, activation of phospholipase D, may be operative. Data presented here demonstrate that stimulation of Jurkat T cells with anti-CD3 antibodies or phorbol esters resulted in activation of phospholipase D, as measured by production of phosphatidylethanol and phosphatidic acid. The combination of anti-CD3 antibody plus phorbol ester led to a greater than additive production of phosphatidylethanol and to the additive production of phosphatidic acid (in the absence of ethanol). Phorbol esters as a second stimulus with anti-CD3 antibody led to a additive increase in cellular diacylglycerol content but provided no increased production of inositol phosphates, suggesting that diacylglycerol production in these cells results from hydrolysis of noninositol containing lipids as well as from phosphinositides. Exogenous addition of phosphatidic acid led to increases in cytosolic calcium that, depending on the concentration used, resulted from release of an intracellular store of calcium and influx of extracellular calcium. Changes in cytosolic calcium occurred in the absence of inositol phosphates production. These studies establish a role for increased phospholipase D activity in T lymphocyte activation.
T淋巴细胞抗原受体/CD3复合物与其同源抗原相互作用会激活许多细胞信号系统。已被充分描述的信号系统包括磷酸肌醇代谢、酪氨酸磷酸化、蛋白激酶C激活以及胞质钙增加。我们探讨了另一种最近描述的信号系统——磷脂酶D的激活可能起作用的可能性。此处呈现的数据表明，用抗CD3抗体或佛波酯刺激Jurkat T细胞会导致磷脂酶D激活，这可通过磷脂酰乙醇和磷脂酸的产生来衡量。抗CD3抗体加佛波酯的组合导致磷脂酰乙醇的产生大于相加效应，而磷脂酸的产生为相加效应（在无乙醇的情况下）。佛波酯作为抗CD3抗体的第二种刺激导致细胞二酰基甘油含量相加性增加，但肌醇磷酸的产生没有增加，这表明这些细胞中二酰基甘油的产生既源于含肌醇脂质的水解，也源于磷脂酰肌醇。外源性添加磷脂酸会导致胞质钙增加，根据所用浓度的不同，这是由细胞内钙储存的释放和细胞外钙的内流引起的。胞质钙的变化在没有肌醇磷酸产生的情况下发生。这些研究确立了磷脂酶D活性增加在T淋巴细胞激活中的作用。
