The efficient translation of most eukaryotic mRNAs requires an interaction between the 5' m7GTP cap structure of mRNA and eIF-4F which is composed of 25-(eIF 4E),46-(eIF-4A), and 220-kDa (p220) subunits. eIF-4E bi...The efficient translation of most eukaryotic mRNAs requires an interaction between the 5' m7GTP cap structure of mRNA and eIF-4F which is composed of 25-(eIF 4E),46-(eIF-4A), and 220-kDa (p220) subunits. eIF-4E binds specifically to the mRNA cap. Evidence indicates that stimulation of eIF-4E phosphorylation increases the efficiency of the translational initiation by an as yet undefined mechanism. Phosphorylation of both eIF-4E and p220 in intact cells is stimulated by growth factors, and eIF-4E phosphorylation appears to be a critical event during cell growth regulation. To date only serine phosphorylation of eIF-4E has been described in vivo. In these studies we found that treatment of HepG2 cells with okadaic acid resulted in eIF-4E phosphorylation on both serine and threonine residues and that tryptic phosphopeptide maps showed several previously unrecognized phosphopeptides. Analysis of p,,' from control and okadaic acid--treated cells dmonstrated serine and threonine phosphorylation under both conditions. The most notable finding was that hyperphosphorylation of eIF-4E and p220 increased binding of p220 but not eIF-4E to the m7GTP.cap structure. we suggest that phosphorylation of eIF-4E is more complicated than previously recognizes and that hyperphosphorylation of eIF-4E and p220recruits more p220 into the protein complex that associate with mRNA caps.展开更多
[Objectives] To study the therapeutic effect and mechanism of New Maixian Powder on ulcerative colitis( UC) rats through observing its regulatory effect on the protein kinase R-like endoplasmic reticulum kinase( PERK)...[Objectives] To study the therapeutic effect and mechanism of New Maixian Powder on ulcerative colitis( UC) rats through observing its regulatory effect on the protein kinase R-like endoplasmic reticulum kinase( PERK)/eukaryotic translation initiation factor-2α( e IF-2α)/nuclear transcription factor-kappa B( NF-κB) signaling pathway. [Methods]First,60 SD rats were randomly divided into normal group,model group,mesalazine group,and New Maixian Powder low,medium and high dose groups,10 rats each group. Then,dextran sulfate sodium( DSS) was used to induce UC rats. The mesalazine group was given 0. 42 g/( kg·d) of mesalazine sustained-release granule suspension,New Maixian Powder low,medium and high dose groups were given 1. 5,3,and 6 g/( kg·d) of New Maixian Powder suspension,respectively,and other groups were given an equal volume of physiological saline,continuous intragastric administration for 14 d. Next,the disease activity index( DAI) of UC rats was evaluated; the expression of NF-κB in serum was measured by enzyme-linked immunosorbent assay( ELISA); the expression of PERK and e IF-2α protein and m RNA in colon tissue was detected by Western blot and real-time quantitative polymerase chain reaction( RT q-PCR). [Results] Compared with the normal group,the DAI score and serum NF-κB level in the model group were significantly higher( P < 0. 05),and PERK and e IF-2α protein and m RNA levels in the colon tissue were increased( P < 0. 05); compared with the model group,the DAI score decreased and serum NF-κB level declined in the New Maixian Powder group,and the expression of PERK and e IF-2α protein and m RNA in New Maixian Powder medium dose and high dose groups declined( P < 0. 05). [Conclusions]New Maixian Powder has good therapeutic effect on UC rats,and its mechanism may be connected with the inhibition of the activation of PERK/e IF-2α/NF-κB signaling pathway.展开更多
文摘The efficient translation of most eukaryotic mRNAs requires an interaction between the 5' m7GTP cap structure of mRNA and eIF-4F which is composed of 25-(eIF 4E),46-(eIF-4A), and 220-kDa (p220) subunits. eIF-4E binds specifically to the mRNA cap. Evidence indicates that stimulation of eIF-4E phosphorylation increases the efficiency of the translational initiation by an as yet undefined mechanism. Phosphorylation of both eIF-4E and p220 in intact cells is stimulated by growth factors, and eIF-4E phosphorylation appears to be a critical event during cell growth regulation. To date only serine phosphorylation of eIF-4E has been described in vivo. In these studies we found that treatment of HepG2 cells with okadaic acid resulted in eIF-4E phosphorylation on both serine and threonine residues and that tryptic phosphopeptide maps showed several previously unrecognized phosphopeptides. Analysis of p,,' from control and okadaic acid--treated cells dmonstrated serine and threonine phosphorylation under both conditions. The most notable finding was that hyperphosphorylation of eIF-4E and p220 increased binding of p220 but not eIF-4E to the m7GTP.cap structure. we suggest that phosphorylation of eIF-4E is more complicated than previously recognizes and that hyperphosphorylation of eIF-4E and p220recruits more p220 into the protein complex that associate with mRNA caps.
文摘目的 探讨宫颈病变组织内蛋白激酶R（PKR）、核因子（NF）-κB p65的表达及磷酸化的意义，高危型人乳头状瘤病毒（hsHPV）对两者表达及磷酸化的影响，以及三者的关系。方法 以67例宫颈癌、149例宫颈上皮内瘤样病变（CINⅠ-Ⅲ）、15例正常人宫颈组织为观察对象。检测各组hsHPV阳性表达情况，采用免疫组化SP法检测组织内PKR、磷酸化型PKR（p-PKR）、NF-κB p65和磷酸化型NF-κB p65（p-NF-κB p65）在上述分组中的表达。结果231例中hsHPV阳性136例，阴性95例。胞浆中PKR、p-PKR在hsHPV阳性组的表达低于hsHPV阴性组（27.2%和11.0% vs 41.1%和21.1%，χ2分别为4.858、4.371，均P＜0.05），在胞浆和胞核中NF-κB p65、p-NF-κB p65在hsHPV阳性组的表达高于hsHPV阴性组（46.3%、25.7%、22.8%和12.5% vs 32.6%、14.7%、11.6%和24.2%，χ2分别为4.345、4.048、4.729、4.650，均P＜0.05）；在胞浆和胞核中NF-κB p65（＋）组PKR的阳性表达率低于NF-κBp65（-）组（25.5%比38.0%和20.4% vs 36.3%，χ2分别为3.898、4.396，P＜0.05），p-NF-κB p65（＋）组在胞浆中PKR的阳性表达率低于p-NF-κBp65（-）组（19.0% vs 36.0%，χ2=4.462，P＜0.05）。结论hsHPV可能抑制PKR的表达及磷酸化而促进NF-κBp65的表达及磷酸化，NF-κBp65的表达及磷酸化对PKR的表达可能有抑制作用；三者间的调节作用可能与宫颈癌的发生发展有关。
基金Supported by Science and Technology Program of Zhejiang Province(2016C33085)
文摘[Objectives] To study the therapeutic effect and mechanism of New Maixian Powder on ulcerative colitis( UC) rats through observing its regulatory effect on the protein kinase R-like endoplasmic reticulum kinase( PERK)/eukaryotic translation initiation factor-2α( e IF-2α)/nuclear transcription factor-kappa B( NF-κB) signaling pathway. [Methods]First,60 SD rats were randomly divided into normal group,model group,mesalazine group,and New Maixian Powder low,medium and high dose groups,10 rats each group. Then,dextran sulfate sodium( DSS) was used to induce UC rats. The mesalazine group was given 0. 42 g/( kg·d) of mesalazine sustained-release granule suspension,New Maixian Powder low,medium and high dose groups were given 1. 5,3,and 6 g/( kg·d) of New Maixian Powder suspension,respectively,and other groups were given an equal volume of physiological saline,continuous intragastric administration for 14 d. Next,the disease activity index( DAI) of UC rats was evaluated; the expression of NF-κB in serum was measured by enzyme-linked immunosorbent assay( ELISA); the expression of PERK and e IF-2α protein and m RNA in colon tissue was detected by Western blot and real-time quantitative polymerase chain reaction( RT q-PCR). [Results] Compared with the normal group,the DAI score and serum NF-κB level in the model group were significantly higher( P < 0. 05),and PERK and e IF-2α protein and m RNA levels in the colon tissue were increased( P < 0. 05); compared with the model group,the DAI score decreased and serum NF-κB level declined in the New Maixian Powder group,and the expression of PERK and e IF-2α protein and m RNA in New Maixian Powder medium dose and high dose groups declined( P < 0. 05). [Conclusions]New Maixian Powder has good therapeutic effect on UC rats,and its mechanism may be connected with the inhibition of the activation of PERK/e IF-2α/NF-κB signaling pathway.
