NIH-3T3 cells transformed by the EJ-ras oncogene exhibit reduced platelet-derived growth factor-mediated Ca2+ mobilization.
NIH-3T3 cells transformed by the EJ-ras oncogene exhibit reduced platelet-derived growth factor-mediated Ca2+ mobilization.
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由 EJ-ras 癌基因转化的 NIH-3T3 细胞表现出血小板衍生生长因子介导的 Ca2+ 动员减少。
DOI：
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发表时间：
1988
影响因子：
11.1
通讯作者：
Robert R. Gorman
中科院分区：
文献类型：
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作者：
C. Benjamin;J. Connor;W. Tarpley;Robert R. Gorman
经EJ-ras癌基因转化的NIH-3 T3细胞在用血小板衍生生长因子（PDGF）刺激后合成的1，4，5-三磷酸肌醇（InsP 3）仅为对照细胞的10-15%。这是尽管在对照和EJ-ras转化细胞中合成的InsP 3的基础（未刺激的）水平没有显著差异的事实。使用荧光指示剂Fura-2和数字成像技术，我们已经可视化和量化的细胞内Ca 2+浓度的变化，在控制和EJ-ras转化的NIH-3 T3细胞响应PDGF。在对照细胞暴露于PDGF后3分钟内，细胞内Ca 2+水平增加3至9倍，与InsP 3的增加平行。相反，大多数（大于90%）EJ-ras转化细胞显示PDGF暴露后Ca 2+水平没有增加，少数应答细胞仅表现出短暂的少量增加。在控制和响应EJ-ras转化细胞的Ca 2+增加的细胞内定位的显着差异也被观察到。尽管InsP 3的合成和随后的Ca 2+动员的抑制，EJ-ras转化的细胞有丝分裂响应PDGF。这些数据不支持EJ-ras基因产物（p21）刺激NIH-3 T3细胞中磷脂酰肌醇4，5-二磷酸特异性磷脂酶C的假设;相反，它们表明EJ-ras p21可能使PDGF受体与磷脂酶C解偶联，从而抑制PDGF刺激的磷脂酶C活性、InsP 3合成和Ca 2+动员。
NIH-3T3 cells transformed by the EJ-ras oncogene synthesize only 10-15% as much inositol 1,4,5-trisphosphate (InsP3) as control cells after stimulation with platelet-derived growth factor (PDGF). This is despite the fact that the basal (unstimulated) levels of InsP3 synthesized in control and EJ-ras-transformed cells are not significantly different. Using the fluorescent indicator fura-2 and digital-imaging techniques, we have visualized and quantified changes in intracellular Ca2+ concentrations in control and EJ-ras-transformed NIH-3T3 cells in response to PDGF. Within 3 min after exposure of control cells to PDGF, intracellular Ca2+ levels are increased 3- to 9-fold, paralleling the increase in InsP3. In contrast, the majority (greater than 90%) of the EJ-ras-transformed cells show no increase in Ca2+ levels after PDGF exposure and the few that did respond exhibited only a small transient increase. Pronounced differences in the intracellular localization of Ca2+ increases in control and the responding EJ-ras-transformed cells were also observed. Despite the inhibition of InsP3 synthesis and subsequent Ca2+ mobilization, the EJ-ras-transformed cells respond mitogenically to PDGF. These data do not support the hypothesis that the EJ-ras gene product (p21) stimulates a phosphatidylinositol 4,5-bisphosphate-specific phospholipase C in NIH-3T3 cells; instead they suggest that the EJ-ras p21 may uncouple the PDGF receptor from phospholipase C resulting in inhibition of PDGF-stimulated activity of phospholipase C, InsP3 synthesis, and Ca2+ mobilization.