Infection Signaling Network Research Center, Research Institute of Medical Sciences, Department of Physiology, School of Medicine, Chungnam National University, 6 Munhwa-dong, Jung-gu, Daejeon, Korea.
Cardiovasc Res. 2011 Aug 1;91(3):502-9. doi: 10.1093/cvr/cvr095. Epub 2011 Apr 4.
Phosphorylation of the adaptor protein p66shc is essential for p66shc-mediated oxidative stress. We investigated the role of the reducing protein/DNA repair enzyme apurinic/apyrimidinic endonuclease1 (APE1) in modulating protein kinase CβII (PKCβII)-mediated p66shc phosphorylation in cultured endothelial cells and PKC-mediated vasoconstriction of arteries.
Oxidized low-density lipoprotein (oxLDL)induced p66shc phosphorylation at serine 36 residue and PKCβII phosphorylation in mouse endothelial cells. Adenoviral overexpression of APE1 resulted in reduction of oxLDL-induced p66shc and PKCβII phosphorylation. Phorbol 12-myristate 13-acetate (PMA), which stimulates PKCs, induced p66shc phosphorylation and this was inhibited by a selective PKCβII inhibitor. Adenoviral overexpression of PKCβII also increased p66shc phosphorylation. Overexpression of APE1 suppressed PMA-induced p66shc phosphorylation. Moreover, PMA-induced p66shc phosphorylation was augmented in cells in which APE1 was knocked down. PMA increased cytoplasmic APE1 expression, compared with the basal condition, suggesting the role of cytoplasmic APE1 against p66shc phosphorylation. Finally, vasoconstriction induced by phorbol-12,13, dibutylrate, another PKC agonist, was partially inhibited by transduction of Tat-APE1 into arteries.
APE1 suppresses oxLDL-induced p66shc activation in endothelial cells by inhibiting PKCβII-mediated serine phosphorylation of p66shc, and mitigates vasoconstriction induced by activation of PKC.
衔接蛋白 p66shc 的磷酸化对于 p66shc 介导的氧化应激至关重要。我们研究了修复酶脱嘌呤/脱嘧啶内切酶 1（APE1）在调节蛋白激酶 CβII（PKCβII）介导的培养内皮细胞中 p66shc 磷酸化和 PKC 介导的动脉血管收缩中的作用。
氧化型低密度脂蛋白（oxLDL）诱导小鼠内皮细胞中 p66shc 的丝氨酸 36 残基磷酸化和 PKCβII 磷酸化。过表达 APE1 可减少 oxLDL 诱导的 p66shc 和 PKCβII 磷酸化。刺激蛋白激酶 C 的佛波醇 12-肉豆蔻酸 13-醋酸酯（PMA）诱导 p66shc 磷酸化，这一过程被选择性 PKCβII 抑制剂抑制。过表达 PKCβII 也增加了 p66shc 的磷酸化。过表达 APE1 抑制了 PMA 诱导的 p66shc 磷酸化。此外，在 APE1 敲低的细胞中，PMA 诱导的 p66shc 磷酸化增强。与基础状态相比，PMA 增加了细胞质 APE1 的表达，提示细胞质 APE1 对 p66shc 磷酸化的作用。最后，另一种 PKC 激动剂佛波醇-12,13-二丁酸酯诱导的血管收缩部分被 APE1 的 Tat 转导抑制。
APE1 通过抑制 PKCβII 介导的 p66shc 丝氨酸磷酸化抑制 oxLDL 诱导的内皮细胞中 p66shc 的激活，并减轻 PKC 激活诱导的血管收缩。
