Fletcher M C, Samelson L E, June C H
Immune Cell Biology Program, Naval Medical Research Institute, Bethesda, Maryland 20889.
J Biol Chem. 1993 Nov 5;268(31):23697-703.
The effects of phenylarsine oxide, a phosphotyrosine phosphatase inhibitor, on early signal transduction events in human T cells were studied. Simultaneous stimulation of T cells with anti-CD3 monoclonal antibody and phenylarsine oxide prevented increased tyrosine phosphorylation of phospholipase C gamma 1. In contrast, treatment of resting T cells with phenylarsine oxide alone resulted in increased tyrosine phosphorylation of a number of other intracellular substrates. Further, phenylarsine oxide was able to cause an immediate disruption of signal transduction in T cells after anti-CD3 stimulation, as measured by a return of intracellular calcium concentration and inositol 1,4,5-trisphosphate production to base-line levels. Surprisingly, in view of the inhibitory effects of phenylarsine oxide on T cell receptor signal transduction, treatment of T cells with phenylarsine oxide alone caused a dose-dependent increase in intracellular-free calcium concentration that was not accompanied with detectable increases in inositol 1,4,5-trisphosphate production. The phenylarsine oxide-induced increase in free calcium had distinct kinetics from antigen receptor-activated calcium mobilization and was derived from both intracellular sources and increased plasma membrane calcium permeability. This effect was independent of the CD45 transmembrane tyrosine phosphatase. Phenylarsine oxide thus has complex effects on signal transduction in T cells that suggests multiple intracellular targets, and these should be considered in the interpretation of experiments using this agent to study cellular kinase and phosphatase interactions. Finally, the effects of phenylarsine oxide on cellular calcium homeostasis may provide a mechanism of action for the therapeutic and/or toxic effects of arsenicals used for various forms of chemotherapy.
研究了磷酸酪氨酸磷酸酶抑制剂氧化苯胂对人T细胞早期信号转导事件的影响。用抗CD3单克隆抗体和氧化苯胂同时刺激T细胞可防止磷脂酶Cγ1的酪氨酸磷酸化增加。相反，单独用氧化苯胂处理静息T细胞会导致许多其他细胞内底物的酪氨酸磷酸化增加。此外，氧化苯胂能够在抗CD3刺激后立即破坏T细胞中的信号转导，这通过细胞内钙浓度和肌醇1,4,5-三磷酸生成恢复到基线水平来衡量。令人惊讶的是，鉴于氧化苯胂对T细胞受体信号转导的抑制作用，单独用氧化苯胂处理T细胞会导致细胞内游离钙浓度呈剂量依赖性增加，而肌醇1,4,5-三磷酸生成没有可检测到的增加。氧化苯胂诱导的游离钙增加具有与抗原受体激活的钙动员不同的动力学，并且来源于细胞内来源和增加的质膜钙通透性。这种效应独立于CD45跨膜酪氨酸磷酸酶。因此，氧化苯胂对T细胞信号转导具有复杂的影响，提示多个细胞内靶点，在解释使用该试剂研究细胞激酶和磷酸酶相互作用的实验时应考虑这些靶点。最后，氧化苯胂对细胞钙稳态的影响可能为用于各种形式化疗的砷剂的治疗和/或毒性作用提供一种作用机制。
