Formation of Ternary Complex of Human Biliverdin Reductase-Protein Kinase Cδ-ERK2 Protein Is Essential for ERK2-mediated Activation of Elk1 Protein, Nuclear Factor-κB, and Inducible Nitric-oxidase Synthase (iNOS)
Formation of Ternary Complex of Human Biliverdin Reductase-Protein Kinase Cδ-ERK2 Protein Is Essential for ERK2-mediated Activation of Elk1 Protein, Nuclear Factor-κB, and Inducible Nitric-oxidase Synthase (iNOS)
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DOI：
10.1074/jbc.m111.279612
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发表时间：
2012-01-06
影响因子：
4.8
通讯作者：
Maines, Mahin D.
中科院分区：
文献类型：
--
作者：
Gibbs, Peter E. M.;Miralem, Tihomir;Maines, Mahin D.
生长因子、胰岛素、氧化应激和细胞因子通过PKC δ和MEK 1/2激活ERK 1/2。人胆绿素还原酶（hBVR），一种Ser/Thr/Tyr激酶和细胞内支架/桥/锚，是MEK 1/2刺激的ERK 1/2的核转运蛋白（Lerner-Marmarosh，N.，Miralem，T.，吉布斯，体育，和Maines，M. D.等人（2008）Proc. Acad. Sci.联合S. A. 105，6870-6875）。hBVR、PKC δ和MEK 1/2在其组织表达谱和激活剂类型上重叠。目前，我们报告了hBVR-PKC delta-ERK 2三元复合物的形成，该复合物对于ERK 2信号转导和与细胞增殖和癌症相关的基因的激活是必需的。MEK 1/2和蛋白磷酸酶PP 2A也存在于复合物中。当细胞被胰岛素样生长因子-1（IGF-1）刺激时，FRET-荧光寿命成像显微镜检测到hBVR和PKC δ之间的相互作用增加。hBVR和ERK 2被PKC δ磷酸化;然而，PKC不是ERK 2或hBVR的底物。IGF-1和佛波酯增加hBVR/PKC δ结合; hBVR是PKC δ激活及其与ERK 2相互作用所必需的。PKC δ的C-末端苯丙氨酸残基（Phe（660）、Phe（663）和Phe（665））是与ERK 2结合所必需的，但不是与hBVR结合所必需的。hBVR-PKC delta-ERK 2复合物的形成需要ERK、FXFP（DEF，C-box）和D（delta）-box（ILXXLXL）基序的hBVR对接位点。基于hBVR的肽KKRILHCLGLA抑制PKC活化和PKC δ/ERK 2相互作用。ERK调节的转录因子Elk 1和NF-κ B的佛波酯和TNF-α依赖性激活以及iNOS基因的表达被hBVR siRNA抑制;这些活性被hBVR拯救。这些发现揭示了hBVR在PKC δ/ERK信号传导中的直接输入，并鉴定了ERK介导的基因激活的基于hBVR的肽调节剂。
Growth factors, insulin, oxidative stress, and cytokines activate ERK1/2 by PKC delta and MEK1/2. Human biliverdin reductase (hBVR), a Ser/Thr/Tyr kinase and intracellular scaffold/bridge/anchor, is a nuclear transporter of MEK1/2-stimulated ERK1/2 (Lerner-Marmarosh, N., Miralem, T., Gibbs, P. E., and Maines, M. D. (2008) Proc. Natl. Acad. Sci. U. S. A. 105, 6870-6875). hBVR, PKC delta, and MEK1/2 overlap in their tissue expression profile and type of activators. Presently, we report on formation of an hBVR-PKC delta-ERK2 ternary complex that is essential for ERK2 signal transduction and activation of genes linked to cell proliferation and cancer. MEK1/2 and the protein phosphatase PP2A were also present in the complex. When cells were stimulated with insulin-like growth factor-1 (IGF-1), an increased interaction between hBVR and PKC delta was detected by FRET-fluorescence lifetime imaging microscopy. hBVR and ERK2 were phosphorylated by PKC delta; however, the PKC was not a substrate for either ERK2 or hBVR. IGF-1 and phorbol ester increased hBVR/PKC delta binding; hBVR was required for the activation of PKC delta and its interaction with ERK2. The C-terminal phenylalanine residues of PKC delta (Phe(660), Phe(663), and Phe(665)) were necessary for binding to ERK2 but not for hBVR binding. Formation of the hBVR-PKC delta-ERK2 complex required the hBVR docking site for ERK, FXFP (DEF, C-box) and D(delta)-box (ILXXLXL) motifs. The hBVR-based peptide KKRILHCLGLA inhibited PKC activation and PKC delta/ERK2 interaction. Phorbol ester-and TNF-alpha-dependent activation of the ERK-regulated transcription factors Elk1 and NF-kappa B and expression of the iNOS gene were suppressed by hBVR siRNA; those activities were rescued by hBVR. The findings reveal the direct input of hBVR in PKC delta/ERK signaling and identify hBVR-based peptide regulators of ERK-mediated gene activation.