P53蛋白与SV40大T抗原之间相互作用的研究

为确定一种定量研究酵母体内蛋白质-蛋白质之间相互作用的简便、快捷的方法,为抗癌小分子化合物药物筛选提供一条可行性途径。本文选择P53蛋白与SV40大T抗原为靶蛋白对,首先用酵母双杂交系统（LiAc法质粒共转化酵母细胞）方法定性证明了两者之间存在相互作用,然后通过α-半乳糖苷酶活力定量测定了相互作用力的大小,并确定了最佳酶活测定时间,并与β-半乳糖苷酶活力测定进行了比较,认为α-关乳糖苷酶活力定量测定是研究蛋白质-蛋白质间相互作用的一种更加简便快捷的方法。     

两种实验技术在蛋白质-蛋白质相互作用检测中的应用

蛋白质是生命活动的主要承担者.蛋白质种类繁多,结构多样,具有十分广泛的生物学功能,可作为载体蛋白、酶蛋白和信号肽等参与调控细胞内的各种代谢活动.生物体内蛋白质与其他分子的相互作用,尤其是蛋白质-蛋白质之间的相互作用,是蛋白质行使这些重要生物学功能的基础.通过研究可以相互作用的蛋白质形成的各种复合体,对揭示蛋白质的功能,...     

活细胞内临近标记技术BioID在蛋白质相互作用研究中的进展

蛋白质往往通过形成复合物或蛋白质间相互作用来执行功能,研究蛋白质相互作用网络具有重要意义.临近依赖的生物素识别技术(proximity-dependent biotin identification technology,BioID)是一种在活细胞中鉴定互作蛋白质组的新工具,其通过构建靶蛋白-生物素连接酶融合蛋白系统,...     

FRET技术及其在蛋白质-蛋白质分子相互作用研究中的应用

简要综述了FRET方法在活细胞生理条件下研究蛋白质-蛋白质间相互作用方面的最新进展.蛋白质-蛋白质间相互作用在整个细胞生命过程中占有重要地位,由于细胞内各种组分极其复杂,因此一些传统研究蛋白质-蛋白质间相互作用的方法,例如酵母双杂交、免疫沉淀等可能会丢失某些重要的信息,无法正确地反映在当时活细胞生理条件下蛋白质-蛋白质间相互作用的动态变化过程.荧光共振能量转移（fluorescence resonance energy transfer, FRET）是近来发展的一项新技术,此项技术的应用,为在活细胞生理条件下对蛋白质-蛋白质间相互作用进行实时的动态研究,提供一个非常便利的条件.     

胃癌相关新蛋白Raf激酶抑制蛋白相互作用蛋白质的鉴定

Raf激酶抑制蛋白(RKIP)的异常表达在胃癌的发生发展中起重要的作用,为了阐明其作用机制,应用脂质体将RKIP-3xFLAG-pcDNA3.1质粒转染至SGC7901细胞,建立RKIP-3xFLAG高表达的SGC7901细胞;并利用3xFLAG标签的亲和层析技术联合质谱分析,分离、鉴定与RKIP相互作用的蛋白质,并应用免疫共沉淀联合Western-blot进一步验证质谱结果．共鉴定出66个RKIP相互作用蛋白质,功能分类包括蛋白质代谢酶类、生物氧化相关酶类,细胞骨架蛋白、分子伴侣、信号转导相关蛋白、酶解相关蛋白等．并首次证实14-3-3蛋白与RKIP存在相互作用．为阐明RKIP在胃癌发生发展中的作用机制提供了重要的线索,为胃癌的早期诊治及预后监测提供了新的靶点．     

14-3-3蛋白与植物细胞信号转导

14-3-3蛋白通过直接蛋白质-蛋白质相互作用对植物代谢关键酶、质膜H^＋ -ATP酶等发挥广泛调节作用。越来越多证据显示14-3-3蛋白通过与转录因子和其他信号分子结合参与调控植物细胞信号转导。对植物细胞中14-3-3蛋白调控信号转导途径,尤其是植物细胞对胁迫响应的调控机制进行了综述。     

双分子荧光互补技术及其在蛋白质相互作用研究中的应用

双分子荧光互补(bimolecularfluorescencecomplementation,BiFC)分析技术,是由Hu等在2002年最先报道的一种直观、快速地判断目标蛋白在活细胞中的定位和相互作用的新技术.该技术巧妙地将荧光蛋白分子的两个互补片段分别与目标蛋白融合表达,如果荧光蛋白活性恢复则表明两目标蛋白发生了相互作用.其后发展出的多色荧光互补技术(multicolorBiFC),不仅能同时检测到多种蛋白质复合体的形成,还能够对不同蛋白质间产生相互作用的强弱进行比较.目前,该技术已用于转录因子,G蛋白βγ亚基的二聚体形式,不同蛋白质间产生相互作用强弱的比较以及蛋白质泛素化等方面的研究工作上.     

SUMO在转录中的抑制作用

许多调控基因转录的重要蛋白质能被SUMO (small ubiquitin-related modifier)化修饰,这些蛋白质包括转录因子,转录辅助因子和染色质修饰酶.SUMO化修饰对底物蛋白的活性产生影响,在大多数情况下,与转录活性的抑制有关.最近,对SUMO化调控转录的机制有了新的认识,认为SUMO化的一个重要作用是促进转录因子与转录抑制因子之间的相互作用.另一方面,已经发现转录共抑制因子HDAC (组蛋白去乙酰化酶)可以作为SUMO化的底物、效应因子和调控因子,说明乙酰化和SUMO化之间复杂的相互作用对基因转录调控起着非常重要的作用.     

应用单克隆抗体鉴定人类肝脏线粒体蛋白质组中的抗原优势蛋白

对线粒体蛋白质组的鉴定和分析有助于理解线粒体的功能和相关疾病的发病机制, 包括能量代谢、凋亡、自由基产生、产热作用、钙离子信号通路等. 本实验旨在鉴定人类肝脏线粒体蛋白质组中的抗原优势蛋白. 用线粒体蛋白质作为免疫原, 经过细胞融合、筛选和克隆, 制备了240多个单克隆抗体杂交瘤细胞系. 单克隆抗体识别的线粒体蛋白抗原通过人类肝脏cDNA表达文库筛选方法鉴定, 相应的线粒体蛋白质的亚细胞定位通过免疫组化证实. 发现了肝脏线粒体中6个抗原优势蛋白, 分别被至少两种特异性的单克隆抗体所识别. 这6个蛋白分别是乙酰辅酶A酰基转移酶(线粒体3-酮酯酰辅酶A硫解酶)2、醛脱氢酶1家族A1、氨甲酰磷酸合成酶1、二氢硫辛酰胺S乙酰转移酶(丙酮酸脱氢酶复合物的E2组分)、烯酰辅酶A水合酶1和羟基类固醇(11β)脱氢酶1. 这些单克隆抗体有望应用于人类肝脏蛋白质组计划的相关研究, 如去除优势蛋白、蛋白与蛋白之间相互作用的研究和验证等.     

酰基辅酶A结合结构域蛋白3在病原微生物复制中的作用

病毒及细菌等病原微生物侵入细胞后,复制过程离不开宿主细胞内的宿主蛋白.近年来研究表明,酰基辅酶A结合结构域蛋白3(ACBD3)可以与一些病原体的蛋白质相互作用,影响病原体微生物在宿主细胞的复制.本文通过总结爱知病毒、柯萨奇病毒、脊髓灰质炎病毒、丙肝病毒、人类鼻病毒以及沙门氏菌侵染宿主细胞时,病毒蛋白质与ACBD3及磷脂酰肌醇4-激酶B(PI4KB)相互作用的研究进展,探讨ACBD3在病原微生物中的作用.     

Identifying Protein-protein Interaction Sites Using Peptide Arrays

Protein-protein interactions mediate most of the processes in the living cell and control homeostasis of the organism. Impaired protein interactions may result in disease, making protein interactions important drug targets. It is thus highly important to understand these interactions at the molecular level. Protein interactions are studied using a variety of techniques ranging from cellular and biochemical assays to quantitative biophysical assays, and these may be performed either with full-length proteins, with protein domains or with peptides. Peptides serve as excellent tools to study protein interactions since peptides can be easily synthesized and allow the focusing on specific interaction sites. Peptide arrays enable the identification of the interaction sites between two proteins as well as screening for peptides that bind the target protein for therapeutic purposes. They also allow high throughput SAR studies. For identification of binding sites, a typical peptide array usually contains partly overlapping 10-20 residues peptides derived from the full sequences of one or more partner proteins of the desired target protein. Screening the array for binding the target protein reveals the binding peptides, corresponding to the binding sites in the partner proteins, in an easy and fast method using only small amount of protein.In this article we describe a protocol for screening peptide arrays for mapping the interaction sites between a target protein and its partners. The peptide array is designed based on the sequences of the partner proteins taking into account their secondary structures. The arrays used in this protocol were Celluspots arrays prepared by INTAVIS Bioanalytical Instruments. The array is blocked to prevent unspecific binding and then incubated with the studied protein. Detection using an antibody reveals the binding peptides corresponding to the specific interaction sites between the proteins.     

Analysis of protein interaction and function with a 3-dimensional MALDI-MS protein array

Protein profiling and characterization of protein interactions in biological samples ultimately require indicator-free methods of signal detection, which likewise offer an opportunity to distinguish specific interactions from nonspecific protein binding. Here we describe a new 3-dimensional protein microchip for detecting biomolecular interactions with matrix-assisted laser desorption-ionization mass spectrometry (MALDI-MS); the microchip comprises a high-density array of methacrylate polymer elements containing immobilized proteins as capture molecules and directly interfaces with a commercially available mass spectrometer. We demonstrated the performance of the chip in three types of experiments by detecting antibody-antigen interactions, enzymatic activity, and enzyme-inhibitor interactions. MALDI-MS biochip-based tumor necrosisfactor alpha (TNF-alpha) immunoassays demonstrated the feasibility of detecting antigens in complex biological samples by identifying molecular masses of bound proteins even at high nonspecific protein binding. By detecting model interactions of trypsin with trypsin inhibitors, we showed that the protein binding capacity of methacrylate polymer elements and the sensitivity of MALDI-MS detection of proteins bound to these elements surpassed that of other 2- and 3-dimensional substrates tested Immobilized trypsin retained functional (enzymatic) activity within the protein microchip and the specificity of macromolecular interactions even in complex biological samples. We believe that the underlying technology should therefore be extensible to whole-proteome protein expression profiling and interaction mapping.     

Metabolic enzymes as targets for 14-3-3 proteins

The 14-3-3 proteins are binding proteins that have been shown to interact with a wide array of enzymes involved in primary biosynthetic and energy metabolism in plants. In most cases, the significance of binding of the 14-3-3 protein is not known. However, most of the interactions are phosphorylation-dependent and most of the known binding partners are found in the cytosol, while some may also be localized to plastids and mitochondria. In this review, we examine the factors that may regulate the binding of 14-3-3s to their target proteins, and discuss their possible roles in the regulation of the activity and proteolytic degradation of enzymes involved in primary carbon and nitrogen metabolism.     

Protein array based interactome analysis of amyloid-β indicates an inhibition of protein translation

Oligomeric amyloid-β is currently of interest in amyloid-β mediated toxicity and the pathogenesis of Alzheimer's disease. Mapping the amyloid-β interaction partners could help to discover novel pathways in disease pathogenesis. To discover the amyloid-β interaction partners, we applied a protein array with more than 8100 unique recombinantly expressed human proteins. We identified 324 proteins as potential interactors of oligomeric amyloid-β. The Gene Ontology functional analysis of these proteins showed that oligomeric amyloid-β bound to multiple proteins with diverse functions both from extra and intracellular localizations. This undiscriminating binding phenotype indicates that multiple protein interactions mediate the toxicity of the oligomeric amyloid-β. The most highly impacted cellular system was the protein translation machinery. Oligomeric amyloid-β could bind to altogether 24 proteins involved in translation initiation and elongation. The binding of amyloid-β to purified rat hippocampal ribosomes validated the protein array results. More importantly, in vitro translation assays showed that the oligomeric amyloid-β had a concentration dependent inhibitory activity on translation. Our results indicate that the inhibited protein synthesis is one of the pathways that can be involved in the amyloid-beta induced neurotoxicity.     

Protein-protein interactions in a higher-order structure direct lambda site-specific recombination

The highly directional site-specific recombination of bacteriophage lambda is tightly regulated by the binding of three different proteins to a complex array of sites. The manner in which these reactions are both stimulated and inhibited by co-operative binding of proteins to specific sites on the P arm of attP and AttR has been elucidated by correlation of nuclease protection with recombination studies of both wild-type and mutant DNAs. In addition to co-operative forces, there is a specific competitive interaction that allows the protein-DNA complex to serve as a "biological switch". This switch does not depend upon the simple occlusion of DNA binding sites by neighboring proteins; but, rather, the outcome of this competition is dependent on long-range interactions that vary between the higher-order structures of attP and attR. These higher-order structures are dependent on cooperative interactions involving three proteins binding to five or more sites.     

Dissecting DNA-protein and protein-protein interactions involved in bacterial transcriptional regulation by a sensitive protein array method combining a near-infrared fluorescence detection

The protein array methodology is used to study DNA-protein and protein-protein interactions governing gene expression from the Bacillus stearothermophilus PargCo promoter-operator region. Using probes labelled with near-infrared fluorescence dyes with exitation characteristics close to 700 or 800 nm, it is possible to detect signals from proteins (purified or non-purified in Escherichia coli cell extracts) immobilised on a nitrocellulose membrane with a high sensitivity (almost 12 amol of a spotted protein for protein-DNA interactions). Protein array data are confirmed by other methods indicating that molecular interactions of the order 10(-7) M can be monitored with the proposed protein array approach. We show that the PargCo region is a target for binding at least three types of regulatory proteins, ArgR repressors from thermophilic bacteria, the E. coli RNA polymerase alpha subunit and cyclic AMP binding protein CRP. We also demonstrate that the high strength of the PargC promoter is related to an upstream element that binds to the E. coli RNA polymerase alpha subunit.     

Systematic identification of SH3 domain-mediated human protein-protein interactions by peptide array target screening

Systematic identification of direct protein-protein interactions is often hampered by difficulties in expressing and purifying the corresponding full-length proteins. By taking advantage of the modular nature of many regulatory proteins, we attempted to simplify protein-protein interactions to the corresponding domain-ligand recognition and employed peptide arrays to identify such binding events. A group of 12 Src homology (SH) 3 domains from eight human proteins (Swiss-Prot ID: SRC, PLCG1, P85A, NCK1, GRB2, FYN, CRK) were used to screen a peptide target array composed of 1536 potential ligands, which led to the identification of 921 binary interactions between these proteins and 284 targets. To assess the efficiency of the peptide array target screening (PATS) method in identifying authentic protein-protein interactions, we examined a set of interactions mediated by the PLCgamma1 SH3 domain by coimmunoprecipitation and/or affinity pull-downs using full-length proteins and achieved a 75% success rate. Furthermore, we characterized a novel interaction between PLCgamma1 and hematopoietic progenitor kinase 1 (HPK1) identified by PATS and demonstrated that the PLCgamma1 SH3 domain negatively regulated HPK1 kinase activity. Compared to protein interactions listed in the online predicted human interaction protein database (OPHID), the majority of interactions identified by PATS are novel, suggesting that, when extended to the large number of peptide interaction domains encoded by the human genome, PATS should aid in the mapping of the human interactome.