Role of protein kinase Cζ in Ras-mediated transcriptional activation of vascular permeability factor/vascular endothelial growth factor expression
Role of protein kinase Cζ in Ras-mediated transcriptional activation of vascular permeability factor/vascular endothelial growth factor expression
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DOI：
10.1074/jbc.m007818200
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发表时间：
2001-01-26
影响因子：
4.8
通讯作者：
Mukhopadhyay, D
中科院分区：
文献类型：
--
作者：
Pal, S;Datta, K;Mukhopadhyay, D
血管通透性因子/血管内皮生长因子（Vascular permeability factor/ Vascular endothelial growth factor, VPF/VEGF）是一种多功能细胞因子，受细胞分化程度、缺氧以及某些致癌基因ras和src等不同因素的调控，ras上调VPF/VEGF的表达是通过转录和mRNA的稳定性两方面来实现的。本研究探讨了Ras通过激活蛋白激酶C zeta （PKC zeta）来促进VPF/VEGF转录的新途径，在共转染实验中，使用PKC zeta的反意义或显性阴性突变体也可以抑制res介导的VPF/VEGF的过表达，通过过表达致癌的Ha-Ras （12 V）和PKC zeta，在活化spll介导的VPF/VEGF转录方面有高达4倍的加性效应。电泳迁移率转移实验表明，Ras促进PKC zeta诱导的Spl与VPF/VEGF启动子的结合。在PKC的主要激活激酶PDK-1存在的情况下，Ras通过PKC zeta介导的VPF/VEGF启动子的激活进一步增加，这表明PKC zeta可以作为Ras和PDK-1的效应物。在其他实验中，使用磷脂酰肌醇3-激酶的显性阴性突变体，通过Ras、PDK-1和PKC zeta激活VPF/VEGF启动子被完全抑制。提示磷脂酰肌醇3-激酶是该途径的重要组成部分。综上所述，这些数据阐明了通过PKC zeta介导的VPF/VEGF转录激活的信号机制，也为PKC zeta和spl依赖的VPF/VEGF转录调控提供了新的视角。
Vascular permeability factor/vascular endothelial growth factor (VPF/VEGF), a multifunctional cytokine, is regulated by different factors including degree of cell differentiation, hypoxia, and certain oncogenes namely, ras and src, The up-regulation of VPF/VEGF expression by Ras has been found to be through both transcription and mRNA stability. The present study investigates a novel pathway whereby Ras promotes the transcription of VPF/VEGF by activating protein kinase C zeta (PKC zeta), The Res-mediated overexpression of VPF/VEGF was also found to be inhibited by using the antisense or the dominant-negative mutant of PKC zeta In co-transfection assays, by overexpressing oncogenic Ha-Ras (12 V) and PKC zeta, there was an additive effect up to 4-fold in activation of Spl-mediated VPF/VEGF transcription. It has been shown through electrophoretic mobility shift assay that Ras promoted the PKC zeta -induced binding of Spl to the VPF/VEGF promoter. In the presence of PDK-1, a major activating kinase for PKC, the Ras-mediated activation of VPF/VEGF promoter through PKC zeta was further increased, suggesting that PKC zeta can serve as an effector for both Ras and PDK-1, In other experiments, with the use of a dominant-negative mutant of phosphatidylinositol 3-kinase, the activation of VPF/VEGF promoter through Ras, PDK-1, and PKC zeta was completely repressed, indicating phosphatidylinositol 3-kinase as an important component of this pathway. Taken together, these data elucidate the signaling mechanism of Res-mediated VPF/VEGF transcriptional activation through PKC zeta and also provide insight into PKC zeta and Spl-dependent transcriptional regulation of VPF/VEGF.