连环蛋白家族成员P120ctn的作用及相关机制

连环蛋白P120可在细胞连接处与E-钙黏蛋白结合形成连环蛋白-钙黏蛋白复合体,调控钙黏蛋白介导的细胞黏附作用;在胞质内可与Rho家族GTP酶相互作用调节细胞骨架的运动;在细胞核内可与核转录因子NF-κB和转录抑制因子Kaiso结合,影响炎性反应和细胞增殖.P120对细胞黏附、细胞动力、炎性反应和细胞增殖的影响使其与损伤修复和肿瘤的发生、发展密切相关.深入研究P120的作用及其相关机制对于进一步研究损伤后修复及肿瘤预防和治疗具有深远的意义.     

肺炎链球菌假想蛋白SPD0414亚细胞定位及对细菌黏附侵袭的影响

目的 为研究肺炎链球菌假想蛋白SPD0414在肺炎链球菌（S.pn）的亚细胞定位,并初步研究其在S.pn黏附和定植中的作用.方法 通过分别在SPD0414的N端和C端融合绿色荧光蛋白（GFP）,共聚焦荧光显微镜观察定位情况.用203野生菌和203△spd0414缺陷菌对鼻咽癌细胞CNE和肺腺癌细胞A549细胞的黏附侵袭实验.体内实验中用203和203△spd0414滴鼻感染BALB/c,在6 h和12 h观察细菌在鼻腔和肺中的载量.结果 无论N端或C端融合的GFP都显示绿色荧光,且整个菌体都显示荧光.与203野生菌相比,203△spd0414缺陷菌对CNE和A549的黏附和侵袭能力均显著下降（P＜0.05）.滴鼻感染BALB/c小鼠,在6 h和12 h,203△spd0414在鼻腔和肺中的细菌载量也明显低于203野生菌（P＜0.05）.结论 肺炎链球菌假想蛋白SPD0414定位于细菌的胞质.该蛋白在细菌的定植和侵袭中发挥了重要的作用.     

黏附分子在肿瘤发生及发展中的作用

细胞黏附分子是以配体和受体相结合的形式,介导细胞与细胞间或细胞与基质间相互作用的一类分子,参与机体的多种重要生理和病理过程.近年来,在对肿瘤发生和发展的研究中发现,黏附分子可通过多种途径影响肿瘤的生长、浸润及转移过程.因此.对黏附分子在肿瘤发生和发展中作用及机制的深入研究,可为肿瘤早期诊断提供重要的分子指标和发现新的治疗靶标.并为进而形成临床诊疗新策略提供重要理论支持.现就几种重要黏附分子在肿瘤生长与转移中的作用进行综述.     

肺炎支原体对宿主细胞黏附机制的研究进展

肺炎支原体通过其末梢尖端结构即黏附细胞器与呼吸道黏膜上皮细胞受体(唾液酸共轭物或糖脂结构域)结合并定植于人体呼吸道,引起原发性非典型性肺炎等疾病。因此,其黏附机制引起了人们的重视。本文着重阐述了肺炎支原体黏附细胞器的形态、结构,黏附素与黏附辅助蛋白的种类、定位、功能及在黏附过程中的协同作用。     

生殖支原体对宿主细胞黏附机制的研究进展

生殖支原体通过其黏附细胞器定植于人体相关组织,引发非淋菌性尿道炎等感染性疾病,但其具体的黏附过程可能相当复杂.探讨其黏附机制有助于了解其致病过程,以促进有关疾病诊断和防治等方面的研究.本文着重介绍了生殖支原体黏附细胞器的形态、结构,各种黏附蛋白的定位、功能及相关基因序列.     

间皮素Mesothelin对大鼠胰岛结构形成和重塑作用的研究进展

大鼠胰腺发育的过程分为以细胞增生、分化为主的早中期及以结构形成、功能完善为主的后期这两个阶段,后期涉及胚胎后期胰岛结构形成和生后胰岛结构重塑.而β细胞的功能完善需要多种细胞迁移和细胞间支持黏附因子的介导,其中表达于β细胞的问皮素(Mesothelin)对细胞间的信号识别以及相互黏附有重要的作用.Mesothelin也是胰腺癌等多种恶性肿瘤的细胞表面标记物.有关Mesothelin在大鼠胰岛结构形成和结构重塑过程中的作用及其与胰腺癌形成关系的作用正处于研究之中.     

肝细胞生长因子对人羊水干细胞迁移和黏附能力的影响

目的分离培养及鉴定羊水干细胞（hAFSC）,并研究肝细胞生长因子（HGF）对羊水干细胞迁移、黏附能力的影响。方法使用细胞贴壁法分离培养羊水干细胞,细胞免疫荧光及westernblot鉴定羊水干细胞,Transwell小室分析HGF对羊水干细胞迁移的作用。明胶贴壁法分析HGF对羊水干细胞黏附能力的作用。两组之间数据的比较采用独立样本t检验。结果分离的羊水干细胞均表达特异性标记物Oct-4、c-kit、SSEA-4、CD105。HGF在体外对hAFSC的迁移有趋化作用,对照组和HGF组每个视野的迁移细胞数分别为38±2.5和80±3.2。对黏附能力有促进作用,对照组和HGF组每个视野的黏附细胞数分别为19±1.5和50±2.7,差异均有统计学意义（P〈0.01）。结论 HGF可趋化羊水干细胞的迁移,增强羊水干细胞的黏附能力。     

淋病奈瑟菌黏附机制的研究进展

淋病导致的公共卫生问题在世界范围内广泛存在.淋病奈瑟菌的唯一宿主是人类,该菌侵袭泌尿生殖道引起淋病.其感染的关键是黏附因子对黏膜细胞的黏附.淋病奈瑟菌主要黏附因子与细胞受体间的作用机制已经在细胞水平上研究得比较清楚,表达淋病奈瑟菌黏附因子受体的转基因动物可望成为淋病研究的合适动物模型,为深入研究淋病奈瑟菌的致病机制、研制淋病疫苗及新型治疗药物提供有效工具.     

双歧杆菌黏附的研究进展

双歧杆菌是人体肠道正常菌群中的优势菌种 ,黏附和定植于肠黏膜上皮细胞后 ,对宿主发挥生物屏障、营养、免疫、抗肿瘤、抗衰老等生理作用。黏附 (ａｄｈｅｓｉｏｎ)是指微生物与宿主上皮细胞通过生物化学作用特异性地连接在一起。由于黏附是微生物与微生物、微生物与宿主相互关系的先决条件之一 ,是定植的第一步。因此 ,有关双歧杆菌黏附的研究越来越受到人们的重视。本文现就这一方面的研究进展作一综述。1　双歧杆菌对肠上皮细胞黏附的特点　　双歧杆菌进入肠道后能否黏附于宿主肠道黏膜上皮细胞表面 ,形成稳定的菌群 ,是关系到其是否能发…     

猪链球菌2型的表面蛋白烯醇化酶在细菌黏附和引发免疫下调中的作用

利用克隆表达获得了具有酶活性的猪链球菌2型(S.suis2)05ZYH33重组烯醇化酶(Enolase)蛋白。流式细胞术FCM的细胞定位发现Enolase可部分存在于S.suis205ZYH33细菌的表面。进而利用Hep2细胞探讨猪链球菌表面Enolase参与细菌对宿主细胞的黏附作用。免疫空斑试验的结果提示,Enolase可能作为一个免疫下调蛋白对于引发猪链球菌相关疾病发挥着重要的作用。     

Innate immune dysfunction in HIV infection: effect of HIV envelope-NK cell interactions

We have previously described a number of NK cell dysfunctions in HIV-viremic individuals. In the present study, we performed DNA microarray analysis followed by phenotypic and functional characterization in an effort to investigate which HIV envelope glycoproteins (gp120) affect the physiologic functions of NK cells. Upon treatment of NK cells with HIV gp120, DNA microarray analyses indicated up-regulation of several categories of genes that are associated with apoptosis, suppression of both cellular proliferation and survival, as well as down-regulation of genes that play a vital role in cell proliferation, innate immune defense mechanism, and cell survival. Both subtypes of gp120 suppressed NK cell cytotoxicity, proliferation, and the ability to secrete IFN-gamma. NK cells exposed to X4-subtype HIV gp120 showed a significant decrease in the levels of CC chemokines, while exposure to R5-subtype HIV gp120 had minimal effect. Extended exposure to HIV gp120 resulted in apoptosis of NK cells, further validating the microarray data. Our data demonstrate that exposure of NK cells to HIV envelope proteins results in profound cellular abnormalities at the level of gene expression as well as generic cell functions. These findings are likely to be a consequence of a direct HIV gp120-mediated effect on NK cells. Identification of specific surface receptors on NK cells that interact with HIV envelope proteins might explain how HIV is capable of circumventing innate immune defense mechanisms and establishing infection in susceptible individuals.     

The p120 family of cell adhesion molecules

p120 is the prototypic member of the p120 subfamily of armadillo-related proteins that includes p0071, delta-catenin/NPRAP, ARVCF and the more distantly related plakophilins 1-3. Like armadillo, beta-catenin and plakoglobin these proteins are involved in mediating cell-cell adhesion. Besides their junctional localization they also reveal a cytoplasmic and nuclear localization. Non-cadherin-associated, cytoplasmic p120 functions in Rho signaling and regulation of cytoskeletal organization and actin dynamics. The nuclear function remains largely unsolved. Some characteristics seem to be shared by the various members of the family but it seems unlikely that p120-related proteins have solely redundant functions and compete for interactions with identical binding partners. Stabilization of cadherins at the membrane seems a common function of p120, p0071, delta-catenin and ARVCF but it is not yet known if and how these proteins confer distinct properties to cellular junctions. Moreover, p0071, NPRAP and ARVCF have a C-terminal PDZ-binding motif that is lacking in p120 pointing to distinct roles of these proteins. PDZ domains are found in a series of proteins involved in establishing cell polarity in epithelial cells. Thus, p120 proteins may not only be master regulators of cadherin abundance and activity but play additional roles in regulating cell polarity. This review focuses on the putative roles of p120 proteins in cell polarity.     

四君子汤加减对大肠癌术前化疗病人免疫功能的影响

目的观察四君子汤加减对大肠癌术前新辅助化疗病人细胞免疫调节作用的影响。方法将40例大肠癌患者按治疗方案分成A组(单纯化疗组)20例,B组(化疗+四君子汤加减治疗组)20例,比较治疗前、后患者细胞免疫功能的变化。结果A、B两组CD3、CD4、NK细胞、CD4/CD8均下降,但下降幅度A组大于B组。A组CD3、CD4、NK细胞明显下降,治疗前、后对比差异有统计学意义(P0.05);CD4/CD8亦有下降,CD8上升,但治疗前、后比较差异无统计学意义(P0.05)。B组治疗后CD3、CD4、NK细胞及CD4/CD8亦有下降,CD8上升,但差异无统计学意义(P0.05)。结论化疗使大肠癌患者细胞免疫功能明显下降,联合四君子汤加减治疗可望使细胞免疫功能得到改善。     

Unraveling the distinct distributions of VE- and N-cadherins in endothelial cells: A key role for p120-catenin

Endothelial cells express two different classical cadherins, vascular endothelial (VE) cadherin and neural (N) cadherin, having distinct functions in the vascular system. VE-cadherin is specific to endothelial adherens junctions and is strictly necessary for vascular morphogenesis. On the contrary, N-cadherin shows diffuse localization on the cell surface and interacts with mural cells for vessel stabilization. In this study, we sought to clarify the cellular mechanisms leading to the distinct cellular locations and functions of the two cadherins in the endothelium. VE-cadherin has been shown to be responsible for the junctional exclusion of N-cadherin. Using several endothelial models, we demonstrate that this property is dependent on VE-cadherin binding to p120 catenin (p120^ctn). Moreover, although in the absence of VE-cadherin N-cadherin can localize to cell contacts, angiogenesis remains impaired, demonstrating that endothelial junction formation is not sufficient for normal vessel development. Interestingly, we show that VE-cadherin, but not N-cadherin, is partially associated with cholesterol-enriched microdomains. Lipid raft-associated-VE-cadherin is characterized by a very high level of p120^ctn association, and this association is necessary for VE-cadherin recruitment into lipid rafts. Altogether, our results indicate a critical role for p120^ctn in regulating the membrane distribution of endothelial cadherins with functional consequences in terms of cadherin stabilization and intracellular signaling.     

Molecular and physiological functions of sphingosine 1-phosphate transporters

Sphingosine 1-phosphate (S1P) is a lipid mediator that plays important roles in diverse cellular functions such as cell proliferation, differentiation and migration. S1P is synthesized inside the cells and subsequently released to the extracellular space, where it binds to specific receptors that are located on the plasma membranes of target cells. Accumulating recent evidence suggests that S1P transporters including SPNS2 mediate S1P release from the cells and are involved in the physiological functions of S1P. In this review, we discuss recent advances in our understanding of the mechanism and physiological functions of S1P transporters. This article is part of a Special Issue entitled New Frontiers in Sphingolipid Biology.     

Investigation of protein-tyrosine phosphatase 1B function by quantitative proteomics

Because of their antagonistic catalytic functions, protein-tyrosine phosphatases (PTPs) and protein-tyrosine kinases act together to control phosphotyrosine-mediated signaling processes in mammalian cells. However, unlike for protein-tyrosine kinases, little is known about the cellular substrate specificity of many PTPs because of the lack of appropriate methods for the systematic and detailed analysis of cellular PTP function. Even for the most intensely studied, prototypic family member PTP1B many of its physiological functions cannot be explained by its known substrates. To gain better insights into cellular PTP1B function, we used quantitative MS to monitor alterations in the global tyrosine phosphorylation of PTP1B-deficient mouse embryonic fibroblasts in comparison with their wild-type counterparts. In total, we quantified 124 proteins containing 301 phosphotyrosine sites under basal, epidermal growth factor-, or platelet-derived growth factor-stimulated conditions. A subset of 18 proteins was found to harbor hyperphosphorylated phosphotyrosine sites in knock-out cells and was functionally linked to PTP1B. Among these proteins, regulators of cell motility and adhesion are overrepresented, such as cortactin, lipoma-preferred partner, ZO-1, or p120ctn. In addition, regulators of proliferation like p62DOK or p120RasGAP also showed increased cellular tyrosine phosphorylation. Physical interactions of these proteins with PTP1B were further demonstrated by using phosphatase-inactive substrate-trapping mutants in a parallel MS-based analysis. Our results correlate well with the described phenotype of PTP1B-deficient fibroblasts that is characterized by an increase in motility and reduced cell proliferation. The presented study provides a broad overview about phosphotyrosine signaling processes in mouse fibroblasts and, supported by the identification of various new potential substrate proteins, indicates a central role of PTP1B within cellular signaling networks. Importantly the MS-based strategies described here are entirely generic and can be used to address the poorly understood aspects of cellular PTP function.     

Cellular behavior in the developing Drosophila pupal retina

Correct patterning of cells within an epithelium is key to establishing their normal function. However, the precise mechanisms by which individual cells arrive at their final developmental niche remains poorly understood. We developed an optimized system for imaging the developing Drosophila retina, an ideal tissue for the study of cell positioning. Using this technique, we characterized the cellular dynamics of developing wild-type pupal retinas. We also analyzed two mutants affecting eye patterning and demonstrate that cells mutant for Notch or Roughest signaling were aberrantly dynamic in their cell movements. Finally, we establish a role for the adherens junction regulator P120-Catenin in retinal patterning through its regulation of normal adherens junction integrity. Our results indicate a requirement for P120-Catenin in the developing retina, the first reported developmental function of this protein in the epithelia of lower metazoa. Based upon our live visualization of the P120-Catenin mutant as well as genetic data, we conclude that P120-Catenin is acting to stabilize E-cadherin and adherens junction integrity during eye development.     

Mutants of human αB-crystallin cause enhanced protein aggregation and apoptosis in mammalian cells: Influence of co-expression of HspB1

Mutations of human αB-crystallin cause congenital cataract and cardio-myopathy by protein aggregation and cell death. How mutations of αB-crystallin become pathogenic is poorly understood. To better understand the cellular events related to protein aggregation and cell death, we transfected cataract and cardio-myopathy causing mutants, R11H, P20S, R56W, D109H, R120G, D140N, G154S, R157H and A171T in HeLa cells and assessed protein aggregation and apoptosis by laser scanning confocal microspy (LSCM) and flow cytometry. Cells individually transfected with the mutants, D109H, R120G, D140N and R157H significantly showed more aggregates. Cells overexpressed with HspB1 (Hsp27) significantly sequestered aggregates in all mutants and suppressed apoptosis in mutants, P20S, D109H and A171T. Significant increases of apoptotic cells as stained with Annexin V were observed in mutants, D109H and A171T transfected cells. Cells positive for active caspase-3 was increased in the mutant, D109H. Thus the previously recognized anti-apoptotic functions of αB-crystallin were compromised in these mutants.