植物促分裂原活化蛋白激酶(mapk)的研究进展

植物促分裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)是一类存在于各种真核生物体中的丝氨酸/苏氨酸型蛋白激酶。它与其它一些信号分子组成MAPK级联信号通路,接受外界刺激信号,将信号传入细胞内,影响特定基因的表达,从而在植物的生长、发育、分化和凋亡等多方面起着重要的作用。而它的作用也受到不同因子的凋节。本文就植物中MAPK的基本组成、分类和功能的最新进展作了综述。     

小分子RAF激酶抑制剂的临床研究进展

MAPK信号通路在调控细胞生长、分化和增值中起着至关重要的作用,RAF是该通路中一个重要的蛋白激酶。文章综述了近年来RAF抑制剂的研究现况,总结了已上市小分子RAF抑制剂的最新临床结果,对处于临床阶段的新化合物进行了简要介绍。     

胎衣不下奶牛母体胎盘中有丝分裂原活化蛋白激酶及细胞外信号调节蛋白激酶基因异常表达的分析

目的分析胎衣不下(retained fetal membranes,RFM)奶牛母体胎盘组织中有丝分裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK,MEK)及细胞外信号调节蛋白激酶(extracellular signal-regulated protein kinase,ERK,p42/44 MAPK)的异常表达。方法选取年龄、胎次、体况相近的产后胎衣正常排出和RFM奶牛各3头,分别为N和R组。产后用子宫内膜采样器采集两组奶牛胎盘样本,Western blot法检测样本中MEK、p42/44 MAPK、P-p42/44MAPK蛋白表达水平,RT-qPCR法检测样本中MEK、p42/44 MAPK基因mRNA转录水平。结果与N组比较,R组奶牛胎盘组织中MEK蛋白表达水平显著下调(P 0. 01),p42/44 MAPK蛋白表达水平下调,但差异无统计学意义(P 0. 05),P-p42/44 MAPK蛋白表达水平显著上调(P 0. 001);R组奶牛胎盘组织中MEK及p42/44 MAPK基因mRNA转录水平均显著下调(P 0. 01)。结论 RFM奶牛母体胎盘组织中MEK与p42/44 MAPK蛋白及m RNA转录水平均明显下调,可能是奶牛RFM发生机制中的关键。     

MAPK/ERK1/2对乳酸杆菌介导的子宫内膜上皮细胞增殖的影响

目的研究乳酸杆菌对子宫内膜上皮细胞增殖的丝裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)通路的作用机制。方法将103个/mL乳酸杆菌与子宫内膜上皮细胞共培养20、40、60 min,各时间点收集细胞,采用Western blot法检测子宫内膜上皮细胞MAPK通路中ERK1/2、JNK、P38蛋白及其磷酸化水平。在子宫内膜上皮细胞中加入40 ng/mL U0126,再加入10^3个/mL乳酸杆菌,共培养20、40、60 min,各时间点收集细胞,采用Western blot及CCK-8法检测U0126对ERK1/2、JNK、P38、p90RSK蛋白磷酸化及细胞增殖的影响。结果乳酸杆菌能促进子宫内膜上皮细胞MAPK通路中ERK1/2蛋白发生磷酸化,共培养40和60 min组ERK1/2磷酸化水平显著增加,与对照(0 min)和20 min组相比,差异有统计学意义(P <0. 05),但与40和60 min组比较,差异无统计学意义(P> 0. 05);MAPK通路中JNK和P38总蛋白水平和磷酸化蛋白水平均无明显变化(P> 0. 05)。40 ng/mL U0126对JNK、P38蛋白磷酸化水平无影响,但能抑制ERK1/2信号通路下游蛋白p90RSK的磷酸化,同时能抑制乳酸杆菌促进子宫内膜上皮细胞增殖。结论乳酸杆菌介导的促进子宫内膜上皮细胞增殖的作用是通过MAPK信号通路中的ERK1/2磷酸化发挥作用的。     

奶牛miR-124a靶基因预测及生物信息学分析

目的预测奶牛miR-124a(bta-miR-124a)的靶基因,并对其生物学功能、调控机制以及参与的信号转导通路进行富集分析,为bta-miR-124a调控乳品质代谢的功能验证研究提供理论依据。方法利用miRBase、miRWalk和Targetscan等在线数据分析系统,获得bta-miR-124a的前体及成熟区序列,同时预测其候选靶基因并取交集,进而对筛选获得的候选靶基因进行GO功能注释及信号通路富集分析。结果 bta-miR-124a序列在各物种间高度保守,其候选靶基因主要富集在生物调控、细胞生长、代谢等生物学过程中。KEGG信号通路显示,在癌症、丝裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)、单磷酸腺苷活化蛋白激酶(AMP-activated protein,AMPK)、环磷酸腺苷(cyclic adenosine monophosphate,c AMP)信号转导、脂肪酸降解、脂肪酸生物合成等信号通路中,候选靶基因均被富集。结论 bta-miR-124a的候选靶基因在癌症发生、AMPK信号转导、脂肪酸代谢中发挥重要作用。其中,脂肪酸代谢是bta-miR-124a可能参与的主要代谢调控通路。为后期bta-miR-124a在奶牛乳腺组织中调控乳脂代谢的功能机制的研究提供参考。     

微量元素硒调节细胞信号传导的研究进展

概述了硒调节细胞信号传导的功能,认为其调节信号通路有：促分裂原激活蛋白激酶信号通路、蛋白激酶C信号通路、核糖体S6蛋白激酶信号通路、转录因子NF-kB和AP-1等。同时认为氧化还原修饰信号分子是硒调节信号传导的主要机制。硒通过作用于信号传导通路而调节细胞的分化、生长、增殖和凋亡,使硒具有生物多样性。     

不同胎龄胎儿皮肤内应激活化蛋白激酶基因的表达分析

目的探讨不同胎龄儿皮肤应激活化蛋白激酶及上游信号因子表达情况及其变化特征。方法采用病理学技术方法对胎龄儿皮肤发育检测进行研究。结果比较不同的胎龄分子丝裂素活化蛋白激酶,应激活化蛋白激酶都存在差异(P<0.05)。而不同胎龄人群肌红蛋白不存在差异。结论分子丝裂素活化蛋白激酶应激活化蛋白激酶可能与皮肤增殖,创伤愈合和细胞凋亡有关。肌红蛋白可能与其无关。     

BC02复合佐剂成分协同增强巨噬细胞固有免疫应答的分析

目的初步分析BC02(BCG Cp G DNA combination adjuvants system 02)复合佐剂构成成分在巨噬细胞激活过程中的协同加强作用。方法采用夹心ELISA和RT-PCR法分别检测BC02复合佐剂及其构成成分[Al(OH)3佐剂及BC01(BCG Cp G DNA compound adjuvants system 01)佐剂]对小鼠巨噬细胞RAW264.7分泌的TNF-α及单核细胞趋化蛋白-1(monocyte chemotactic protein 1,MCP-1)细胞因子水平和m RNA转录水平的影响。信号通路蛋白磷酸化芯片检测经BC01和BC02刺激45 min后,RAW264.7细胞中核转录因子-κB(nuclear factor-κB,NF-κB)和促分裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)信号通路的变化情况。结果 BC02对巨噬细胞的刺激存在剂量和时间依赖性,最佳浓度和培养时间分别为1/10人用剂量[(7.5μg/m L BC01+20μg/m L Al(OH)3]和24 h。Al(OH)3无机盐佐剂能协同增强BC01生物佐剂对RAW264.7细胞的刺激活性,同时,TLR-9抑制剂ODN 2088与NLRP3抑制剂MCC 950单独或联合处理RAW264.7细胞,均能显著降低BC02刺激RAW264.7细胞分泌TNF-α和MCP-1细胞因子的能力。信号通路蛋白磷酸化芯片结果表明,BC02复合佐剂显著上调NF-κB信号通路中NF-κB-p105/p50、NF-κB-p65及NF-κB-p100/p52等关键蛋白分子的磷酸化水平;同时,也能显著上调MAPK信号通路中p38 MAPK、c-Jun、SPAK/JNK及EIK-1等关键蛋白分子的磷酸化水平。结论 BC02复合佐剂中BC01生物佐剂与Al(OH)3无机盐佐剂成分在激活小鼠巨噬细胞参与固有免疫应答中具有协同加强作用。     

影响皮肤光老化信号通路的植物提取物

人体衰老过程中伴随着皮肤形态和生理的恶化，并随着年龄的增长而逐渐表现出来，如色素沉积、皱纹、干燥等。光老化是导致皮肤老化的主要原因，因此，研究光老化的信号通路以及探究相关的影响信号通路延缓皮肤衰老的植物提取物具有非常重要的意义。论文综述了调控皮肤光老化的主要信号通路，包括TGF-β1/Smad信号通路、NF-KB信号通路、Nrf2/ARE信号通路和MAPK信号通路，并重点介绍通过调控各种信号通路延缓皮肤衰老的植物提取物。通过对植物提取物抗光老化成分的详细阐述，以期为植物提取物更好地应用到抗衰老化妆品中提供借鉴。     

化妆品植物原料（Ⅳ）——抑制黑色素合成信号通路的植物美白原料的研究与开发

人类的皮肤和头发的颜色取决于黑色素的数量、质量和分布。黑色素在保护皮肤免受各种环境的有害影响方面发挥巨大的作用。而黑色素过量合成会导致严重的皮肤问题。因此,研究黑色素生物合成的信号通路调控以及探究相关的经信号通路抑制黑色素合成的植物提取物具有非常重要的意义。本文综述了调控黑色素生物合成的信号通路和调控因子,包括α-MSH诱导的信号通路、PI3K/Akt信号通路、SCF/c-kit介导的MAPK信号通路、Wnt/β-catenin信号通路、NO/cGMP信号通路、以及细胞因子、转录因子PAX3和肝X受体。重点介绍通过调控各种信号通路抑制黑色素合成的植物提取物。这些植物提取物虽然通过不同的信号通路进行调控,但大多下调一种整合上游信号通路和调控下游基因的转录因子MITF的表达,进而降低酪氨酸酶(TYR)的表达,抑制细胞内黑色素的生物合成。     

Update on the Roles of Rice MAPK Cascades

The mitogen-activated protein kinase (MAPK) cascades have been validated playing critical roles in diverse aspects of plant biology, from growth and developmental regulation, biotic and abiotic stress responses, to phytohormone signal transduction or responses. A classical MAPK cascade consists of a MAPK kinase kinase (MAPKKK), a MAPK kinase (MAPKK), and a MAPK. From the 75 MAPKKKs, eight MAPKKs, and 15 MAPKs of rice, a number of them have been functionally deciphered. Here, we update recent advances in knowledge of the roles of rice MAPK cascades, including their components and complicated action modes, their diversified functions controlling rice growth and developmental responses, coordinating resistance to biotic and abiotic stress, and conducting phytohormone signal transduction. Moreover, we summarize several complete MAPK cascades that harbor OsMAPKKK-OsMAPKK-OsMAPK, their interaction with different upstream components and their phosphorylation of diverse downstream substrates to fulfill their multiple roles. Furthermore, we state a comparison of networks of rice MAPK cascades from signal transduction crosstalk to the precise selection of downstream substrates. Additionally, we discuss putative concerns for elucidating the underlying molecular mechanisms and molecular functions of rice MAPK cascades in the future.     

Mitogen-Activated Protein (MAP) Kinases in Plant Metal Stress: Regulation and Responses in Comparison to Other Biotic and Abiotic Stresses

Exposure of plants to toxic concentrations of metals leads to disruption of the cellular redox status followed by an accumulation of reactive oxygen species (ROS). ROS, like hydrogen peroxide, can act as signaling molecules in the cell and induce signaling via mitogen-activated protein kinase (MAPK) cascades. MAPK cascades are evolutionary conserved signal transduction modules, able to convert extracellular signals to appropriate cellular responses. In this review, our current understanding about MAPK signaling in plant metal stress is discussed. However, this knowledge is scarce compared to research into the role of MAPK signaling in the case of other abiotic and biotic stresses. ROS production is a common response induced by different stresses and undiscovered analogies may exist with metal stress. Therefore, further attention is given to MAPK signaling in other biotic and abiotic stresses and its interplay with other signaling pathways to create a framework in which the involvement of MAPK signaling in metal stress may be studied.     

Pseudophosphatases as Regulators of MAPK Signaling

Mitogen-activated protein kinase (MAPK) signaling pathways are highly conserved regulators of eukaryotic cell function. These enzymes regulate many biological processes, including the cell cycle, apoptosis, differentiation, protein biosynthesis, and oncogenesis; therefore, tight control of the activity of MAPK is critical. Kinases and phosphatases are well established as MAPK activators and inhibitors, respectively. Kinases phosphorylate MAPKs, initiating and controlling the amplitude of the activation. In contrast, MAPK phosphatases (MKPs) dephosphorylate MAPKs, downregulating and controlling the duration of the signal. In addition, within the past decade, pseudoenzymes of these two families, pseudokinases and pseudophosphatases, have emerged as bona fide signaling regulators. This review discusses the role of pseudophosphatases in MAPK signaling, highlighting the function of phosphoserine/threonine/tyrosine-interacting protein (STYX) and TAK1-binding protein (TAB 1) in regulating MAPKs. Finally, a new paradigm is considered for this well-studied cellular pathway, and signal transduction pathways in general.     

ERK in Learning and Memory: A Review of Recent Research

The extracellular signal-regulated kinase (ERK) pathway is a member of the mitogen-activated protein kinase (MAPK) superfamily, which is an important, highly conserved family of enzymes associated with cell membrane receptors and regulative targets. In the central nervous system, there is almost no mature neuronal proliferation and differentiation, but the regulation of MAPK and its upstream and downstream molecular pathways is still widespread, with the ERK signaling pathway being one of the most actively studied signal transduction pathways. It is activated by a variety of cell growth factors and substances which promote mitotic activity, and transmits extracellular signals from the cell surface to the nucleus, which transmission plays an important role in the process of cell proliferation and differentiation. In recent years, accumulating evidence has shown that the ERK signaling pathway has an important link with the higher functions of learning and memory.     

Anti-Inflammatory Effects of Stearidonic Acid Mediated by Suppression of NF-κB and MAP-Kinase Pathways in Macrophages

Stearidonic acid (SDA, 18:4n-3) is an omega-3 polyunsaturated fatty acid present in oils derived from plants of the Boraginaceae family. In this study, we determined the anti-inflammatory effects of SDA isolated from echium oil on lipopolysaccharide (LPS)-induced inflammatory responses in RAW 264.7 macrophages. SDA significantly downregulated the levels of the inducible nitric oxide synthase (iNOS) protein, thereby suppressing the production of nitric oxide (NO) in LPS-stimulated RAW 264.7 cells. In addition, SDA inhibited the nuclear translocation and promoter activity of nuclear factor κB (NFκB) and the phosphorylation of mitogen-activated protein kinases (MAPK) such as extracellular signal regulated kinase 1/2, c-jun N terminal kinase, and p38 in LPS-stimulated RAW 264.7 cells. Our results showed that SDA exerted anti-inflammatory effects by suppressing iNOS-mediated NO production via inactivation of NFκB and MAPK signaling pathways.     

MAPKs and Signal Transduction in the Control of Gastrointestinal Epithelial Cell Proliferation and Differentiation

Mitogen-activated protein kinase (MAPK) pathways are activated by several stimuli and transduce the signal inside cells, generating diverse responses including cell proliferation, differentiation, migration and apoptosis. Each MAPK cascade comprises a series of molecules, and regulation takes place at different levels. They communicate with each other and with additional pathways, creating a signaling network that is important for cell fate determination. In this review, we focus on ERK, JNK, p38 and ERK5, the major MAPKs, and their interactions with PI3K-Akt, TGFβ/Smad and Wnt/β-catenin pathways. More importantly, we describe how MAPKs regulate cell proliferation and differentiation in the rapidly renewing epithelia that lines the gastrointestinal tract and, finally, we highlight the recent findings on nutritional aspects that affect MAPK transduction cascades.     

Structural Optimization and Biological Screening of a Steroidal Scaffold Possessing Cucurbitacin‐Like Functionalities as B‐Raf Inhibitors

Inhibition of the mitogen‐activated protein kinase (MAPK) pathway by targeting the commonly occurring mutated B‐Raf in melanoma has become a practical method for the development of drugs and drug candidates. In order to expand upon the currently reported structural scaffolds used to target the MAPK pathway, molecular docking studies led to the installation an α,β‐unsaturated ketone side chain, related to the cucurbitacin class of natural products, on to an estrone core via an aldol condensation reaction, along with installation of the Δ^9,11 olefin to assemble what has been defined as a pseudo‐cis configuration at the B/C ring juncture. Combination of these cucurbitacin‐like features resulted in a compound with an enhanced biological profile against the A‐375 mutant B‐Raf cell line, in regards to their cytotoxicity and inhibitory activity toward phosphorylated extracellular‐signal‐regulated kinase (ERK).     

Plant Mitogen-Activated Protein Kinase Cascades in Environmental Stresses

Due to global warming and population growth, plants need to rescue themselves, especially in unfavorable environments, to fulfill food requirements because they are sessile organisms. Stress signal sensing is a crucial step that determines the appropriate response which, ultimately, determines the survival of plants. As important signaling modules in eukaryotes, plant mitogen-activated protein kinase (MAPK) cascades play a key role in regulating responses to the following four major environmental stresses: high salinity, drought, extreme temperature and insect and pathogen infections. MAPK cascades are involved in responses to these environmental stresses by regulating the expression of related genes, plant hormone production and crosstalk with other environmental stresses. In this review, we describe recent major studies investigating MAPK-mediated environmental stress responses. We also highlight the diverse function of MAPK cascades in environmental stress. These findings help us understand the regulatory network of MAPKs under environmental stress and provide another strategy to improve stress resistance in crops to ensure food security.     

Are MAP Kinases Drug Targets? Yes,but Difficult Ones

Pharmaceutical companies are facing an increasing interest in new target identification and validation. In particular, extensive efforts are being made in the field of protein kinase inhibitors research and development, and the past ten years of effort in this field have altered our perception of the potential of kinases as drug targets. Therefore, in the drug discovery process, the selection of relevant, susceptible protein kinase targets combined with searches for leads and candidates have become a crucial approach. The success of recent launches of protein kinase inhibitors (Gleevec, Imatinib, Sutent, Iressa, Nexavar, Sprycel) gave another push to this field. Numerous other kinase inhibitors are currently undergoing clinical trials or clinical development. Some questions are nevertheless unanswered, mostly related to the great number of known kinases in the human genome, to their similarity with each other, to the existence of functionally redundant kinases for specific pathways, and also because the connection between particular pathways and diseases is not always clear. The review is leading the reader through a panoramic view of protein kinase inhibition with a major focus on MAPK, successful examples and clinical candidates.