【摘要】： CUEDC2目前是一個(gè)功能未知的蛋白質(zhì)，通過生物信息學(xué)分析發(fā)現(xiàn)，CUEDC2包含一個(gè)CUE結(jié)構(gòu)域。CUE是一個(gè)非常小的中度保守的結(jié)構(gòu)域，大約包含40個(gè)氨基酸，預(yù)測它能和泛素結(jié)合，既能識別單泛素化又能識別多泛素化，目前發(fā)現(xiàn)它存在各種真核蛋白質(zhì)中。最近，我們實(shí)驗(yàn)室發(fā)現(xiàn)CUEDC2能夠和孕激素受體結(jié)合，促進(jìn)孕激素誘導(dǎo)的受體的泛素化和降解(張佩景等，EMBO J．)，，并抑制乳腺癌細(xì)胞的生長，這就為CUEDC2在乳腺癌增殖過程中的作用提供了重要的線索。本文為進(jìn)一步揭示CUEDC2的功能，在應(yīng)用酵母雙雜交技術(shù)篩選與CUEDC2相互作用蛋白質(zhì)的基礎(chǔ)上，對其功能尤其是在NF-κB通路中的作用進(jìn)行了更為深入的研究。 我們通過研究發(fā)現(xiàn)一個(gè)未知功能的蛋白CUEDC2(CUE Domain Containing 2)能夠結(jié)合IKKα和IKKβ，并且能夠通過使IKKα和IKKβ去磷酸化而抑制NF-κ信號通路。在細(xì)胞因子誘導(dǎo)的NF-κB通路激活中，IκB激酶IKKα和IKKβ的激活是關(guān)鍵的步驟。因此，對IKK復(fù)合體磷酸化的精確調(diào)控是NF-κB通路信號傳導(dǎo)的重要組成部分。利用siRNA抑制內(nèi)源CUEDC2表達(dá)導(dǎo)致TNF誘導(dǎo)的NF-κB轉(zhuǎn)錄活性增加，過表達(dá)CUEDC2增加了細(xì)胞對凋亡信號如TNF誘導(dǎo)的凋亡。我們還發(fā)現(xiàn)CUEDC2與蛋白磷酸酶1(PP1)的調(diào)節(jié)亞基生長抑制和DNA損傷蛋白34(GADD34)存在相互作用。此外，我們發(fā)現(xiàn)CUEDC2對NF-κB信號通路的抑制是由IKK-CUEDC2-GADD34相互作用介導(dǎo)的。siRNA抑制內(nèi)源CUEDC2的實(shí)驗(yàn)證明CUEDC2對于IKK-CUEDC2-GADD34復(fù)合體的形成是必須的，并且作為招募蛋白使IKK去磷酸化。因此，我們發(fā)現(xiàn)了NF-κB信號通路一個(gè)新的抑制蛋白，對CUEDC2在NF-κB信號通路中的作用提供了線索。
[Abstract]:CUEDC2 is a protein with unknown function. Bioinformatics analysis shows that CUEDC2 contains a CUE domain. Cue is a very small, moderately conserved domain containing about 40 amino acids, which is predicted to bind to ubiquitin. It can recognize both monoubiquitization and polyubiquitin. At present, it is found to exist in various eukaryotic proteins. Recently, our lab found that CUEDC2 binds to progesterone receptors, promoting the ubiquification and degradation of progesterone-induced receptors (Zhang Peijing, et al., Embo J.), and inhibits the growth of breast cancer cells. This provides important clues for the role of CUEDC2 in breast cancer proliferation. In order to further reveal the function of CUEDC2, especially in the NF- 魏 B pathway, was studied based on the screening of proteins interacting with CUEDC2 by yeast two-hybrid technique. We found that an unknown functional protein CUEDC2 (CUE Domain Containing 2) could bind IKK 偽 and IKK 尾, and inhibit NF- 魏 signaling pathway by dephosphorylation of IKK 偽 and IKK 尾. Activation of I 魏 B kinase IKK 偽 and IKK 尾 is a key step in cytokine induced activation of NF- 魏 B pathway. Therefore, the precise regulation of phosphorylation of IKK complex is an important part of NF- 魏 B pathway signal transduction. Inhibition of endogenous CUEDC2 expression by siRNA resulted in an increase in NF- 魏 B transcription activity induced by TNF, while overexpression of CUEDC2 increased apoptosis induced by TNF. We also found that CUEDC2 interacts with regulatory subunit growth inhibition of protein phosphatase 1 (PP1) and DNA damage protein 34 (GADD34). In addition, we found that the inhibition of NF- 魏 B signaling pathway by CUEDC2 is mediated by IKK-CUEDC2-GADD34 interaction. SiRNA inhibits endogenous CUEDC2. It is proved that CUEDC2 is necessary for the formation of IKK-CUEDC2-GADD34 complex, and IKK is dephosphorylated as a recruitment protein. Therefore, we have discovered a new inhibitory protein of NF- 魏 B signaling pathway, which provides clues to the role of CUEDC2 in NF- 魏 B signaling pathway.
【學(xué)位授予單位】：中國人民解放軍軍事醫(yī)學(xué)科學(xué)院
【學(xué)位級別】：博士
【學(xué)位授予年份】：2007
【分類號】：R341

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1 李慧艷;CUEDC2通過抑制IKK復(fù)合體磷酸化下調(diào)NF-κB通路[D];中國人民解放軍軍事醫(yī)學(xué)科學(xué)院;2007年

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