Small GTPases:Structure,biological function and its interaction with nanoparticles

Small GTPase is a kind of GTP-binding protein commonly found in eukaryotic cells.It plays an important role in cytoskeletal reorganization,cell polarity,cell cycle progression,gene expression and many other significant events in cells,such as the interaction with foreign particles.Therefore,it is of great scientific significance to understand the biological properties of small GTPases as well as the GTPase-nano interplay,since more and more nanomedicine are supposed to be used in biomedical field.However,there is no review in this aspect.This review summarizes the small GTPases in terms of the structure,biological function and its interaction with nanoparticles.We briefly introduced the various nanoparticles such as gold/silver nanoparticles,SWCNT,polymeric micelles and other nano delivery systems that interacted with different GTPases.These current nanoparticles exhibited different pharmacological effect modes and various target design concepts in the small GTPases study.This will help to elucidate the conclusion that the therapeutic strategy targeting small GTPases might be a new research direction.It is believed that the in-depth study on the functional mechanism of GTPases can provide insights for the design and study of nanomedicines.

Small GTPases and cilia

Small GTPases are key molecular switches that bind and hydrolyze GTP in diverse membrane-and cytoskeletonrelated cellular processes.Recently,mounting evidences have highlighted the role of various small GTPases,including the members in Arf/Arl,Rab,and Ran subfamilies,in cilia formation and function.Once overlooked as an evolutionary vestige,the primary cilium has attracted more and more attention in last decade because of its role in sensing various extracellular signals and the association between cilia dysfunction and a wide spectrum of human diseases,now called ciliopathies.Here we review recent advances about the function of small GTPases in the context of cilia,and the correlation between the functional impairment of small GTPases and ciliopathies.Understanding of these cellular processes is of fundamental importance for broadening our view of cilia development and function in normal and pathological states and for providing valuable insights into the role of various small GTPases in disease processes,and their potential as therapeutic targets.

Fine-tuning cell organelle dynamics during mitosis by small GTPases

During mitosis,the allocation of genetic material concurs with organelle transformation and distribution.The coordination of genetic material inheritance with organelle dynamics directs accurate mitotic progression,cell fate determination,and organismal homeostasis.Small GTPases belonging to the Ras superfamily regulate various cell organelles during division.Being the key regulators of membrane dynamics,the dysregulation of small GTPases is widely associated with cell organelle disruption in neoplastic and non-neoplastic diseases,such as cancer and Alzheimer’s disease.Recent discoveries shed light on the molecular properties of small GTPases as sophisticated modulators of a remarkably complex and perfect adaptors for rapid structure reformation.This review collects current knowledge on small GTPases in the regulation of cell organelles during mitosis and highlights the mediator role of small GTPase in transducing cell cycle signaling to organelle dynamics during mitosis.

肺癌细胞系中p120-catenin的基因缺失调控small GTP酶活性

背景与目的作为catenin蛋白家族的重要成员之一,p120-catenin(p120ctn)是small GTPase酶的重要调节因子,影响细胞的运动能力,但其中具体的调节机制尚不清楚。本研究旨在探讨p120ctn在肺癌细胞系中对small GTP酶家族核心成员的调节作用,及其对肺癌细胞侵袭、转移的影响。方法应用siRNA方法成功地建立了p120ctn基因沉默的多种癌细胞系BE1、SPC、LTE的细胞克隆,采用Western Blot,pull-down蛋白活性分析,裸鼠移植等体内外实验探讨其可能的调节机制。结果p120ctn的基因沉默能激活Cdc42和Rac1,失活RhoA,并且在活体内外促进肺癌细胞的侵袭和转移。结论p120ctn的缺失可激活Cdc42/Rac1、失活RhoA,促进肺癌细胞的侵袭和转移能力。

Rho GTPases途径在非小细胞肺癌中的表达及其临床意义

目的:探讨Rho GTPases在非小细胞肺癌(non-small cell lung cancer,NSCLC)中的表达及其临床意义。方法:应用RT-PCR和免疫组织化学法检测36例NSCLC组织Rho GTPases信号转导途径中的RhoC、E-钙黏附素、基质金属蛋白酶-2(matrix metalloproteinases-2,MMP-2)和MMP-9的表达。通过绘制Kaplan-Meier生存曲线分析RhoC mRNA的表达与患者预后的关系。结果:RhoC mRNA在NSCLC组织和癌旁正常组织中的表达存在差异(P<0.01),RhoC mRNA的表达与患者的性别、年龄、肿瘤浸润程度、淋巴结转移、肿瘤大小、组织学类型和分化程度无关,而与不同TNM分期有关(P<0.05)。RhoC蛋白与MMP-2蛋白的表达呈正相关(r=0.474,P=0.003)。RhoC mRNA低表达组患者的生存时间长于高表达组患者,但2者之间差异无统计学意义。结论:RhoC mRNA的高表达可能与NSCLC的发生和发展有关,也可能与NSCLC的早期及中期浸润和转移有关。

小GTPase蛋白家族的研究进展

[目的]综述小G蛋白家族的研究进展,为更深入地解析小G蛋白的结构、功能及其分子作用模式提供参考。[方法]介绍了小G蛋白的结构、作用机制以及分类,着重综述了其各个亚家族的生物学功能。[结果]小G蛋白是真核生物的1个超基因家族,其成员超过100个,被分为Ras、Rho、Rab、Sar/Arf和Ran5个亚家族,分别参与细胞骨架组装、基因表达、细胞壁合成、囊泡运输、核质运输、微管形成、酵母出芽、纺锤体组装及细胞极性生长等诸多生命体活动过程。[结论]小G蛋白家族成员庞大,其分子作用机制及其调控的复杂网络有待进一步研究。

海洋生物小GTPase蛋白家族研究进展

小GTPase蛋白家族是一类普遍存在于真核生物的GTP结合蛋白超家族,具有众多家族成员,按照其序列结构特征和生物学功能的不同,主要可以分为Ras、Rho、Rab、Ran和Arf 5个亚家族。诸多研究显示,小GTPase蛋白家族成员在细胞分化、生长发育、肿瘤发生等过程中均发挥着重要作用。小GTPase蛋白家族成员在调控海洋生物细胞分化、骨骼发育和免疫应答等生理生化过程中的作用受到人们的广泛关注。本研究中综述了近年来对海洋生物中小GTPase蛋白家族成员的研究进展,包括其种类、功能和作用机制,以期为进一步深入了解海洋生物小GTPase蛋白家族成员的基因序列特征、进化特点和生物学功能提供更多的信息和资料。

Wound Closure on the Neonatal Rat Skin II. The Potential Ability of Epidermis to Close Small-Sized Wounds Independently of the Underlying Dermis

Reepithelialization of skin which comprises epidermis and dermis has not been fully elucidated due to the complexity of the participants as well as the interactions therein. In this study, the intrinsic roles and behaviors of epidermis itself during wound closure on neonatal rat skin were explored by developing and utilizing a novel in vivo wound model, termed “shallow incisional wound” in which the injury of dermis was minimized. The shallow wounds were closed by 12 h postwounding (PW) by the migration of the wound-marginal epidermal sheets in which activated myosin light chain (p-MLC) was predominantly detected at the lateral plasma membrane of individual cells. By local administration of Rho-associated protein kinase (ROCK) inhibitor Y27632, p-MLC disappeared at the wound margin and wounds were not closed by 12 h PW. Inhibition of Rac 1 by NSC23766 also resulted in hold of wound closure by 12 h PW, though NSC23766 somewhat slowly acted on p-MLC expression. These results suggest that, without joining of dermis, epidermal cells have a potential ability of closing wounds by active epithelial sheet movement integrated by Rho family small GTPases-dependent extension and contraction of the individual cell bodies.

Rho and Ras GTPases in semaphorin-mediated neuronal development

Neurons are highly polarized cells with a single long axon and multiple dendrites, all of which are actinrich structures. The precise regulation of neuronal cell morphology is a fundamental aspect of neurobiology. The major role of Rho GTPases, which is conserved in all eukaryotes, is to regulate the actin and microtubule cytoskeleton. Therefore theRhoGTPases are key regulators of neuronal morphology during development besides their canonical functions in actin cytoskeletal regulation, cell migration and cell cycle progression. Semaphorins are a family of secreted or transmembrane proteins, which function through their receptor plexins and/or neuropilins to act as the repulsive or attractive guidance cues for axons and dendrites. It has been demonstrated that the fully activetion of plexins appears to be dependent on the binding of RhoGTPases to theRhobinding domain (RBD) and Semaphorin to the extracellular region. Here, we summarize the functions of the small Rho GTPases in two well-studied vertebrate Semaphorins, Sema3Aand Sema4D;and the potential roles of the small Rho GTPases in some poorly-studied vertebrate Semaphorins Sema5A, Sema6Aand Sema7A. We also summarize the functions of different members of Ras family, R-Ras, M-Ras and Rap, in Semaphorin signalling pathways as well.

GTP酶激活蛋白SH3功能区结合蛋白1在非小细胞肺癌中的表达及其与放疗疗效的关系

【目的】探讨GTP酶激活蛋白SH3功能区结合蛋白1(G3BP1)在非小细胞肺癌(NSCLC)患者组织中的表达及其与放疗疗效的关系。【方法】检测133例NSCLC患者组织中G3BP1蛋白表达水平,并分析其与NSCLC临床病理参数及放疗疗效的关系。【结果】NSCLC患者组织中G3BP1蛋白水平在不同肿瘤直径、TNM分期及淋巴结转移患者中比较,差异均有统计学意义(P<0.05)。有效组NSCLC组织中G3BP1蛋白水平低于无效组,差异有统计学意义(P<0.05)。G3BP1评价疗效的受试者工作特征(ROC)曲线下面积(AUC)、最佳截断值、敏感度和特异度分别为0.802、2.33、86.54%和61.73%。Logistic多因素回归分析结果显示:肿瘤直径、TNM分期、淋巴结转移、急性放射性肺炎及G3BP1水平是影响NSCLC放疗疗效的独立危险因素(P<0.05)。【结论】G3BP1与NSCLC肿瘤直径、TNM分期及淋巴结转移有关,其水平可为评价患者的放疗疗效提供参考。

Preliminary Characterization of Function of Rac /Rop GEF1 in Arabidopsis

[Objective]The aim was to research the function of AtGEF1 in Rac/Rop GTPses mediate auxin signal passway.[Method]Using the transgenic plants of AtGEF1 promotor fused with GUS reporter gene and the over-expression plants of Rac/Rop GEF1 under the control of 35S promoter as materials,which were constructed from our lab,the expression pattern of GEF1 was analyzed by GUS assay using histochemical staining,and the development of seedling roots of over-expression plant of GEF1 was observed.[Result]GEF1 expression was mainly detected in root meristem,root vascular tissue,lateral roots and root hair.Furthermore,the expression level of GEF1 was highly increased with the induction of NAA.Over-expression of GEF1 was observed to enhance lateral root formation.[Conclusion]GEF1 may be involved in the regulation of development of root and root hair,and it may have redundant function in the control of lateral root development.

阿托伐他汀的抗炎作用及其机制的研究进展

阿托伐他汀具有强效降脂功能,目前已被广泛用于高脂血症和心血管疾病的治疗。此外,阿托伐他汀还能明显抑制白细胞介素1β(IL-1β)、白细胞介素6(IL-6)、肿瘤坏死因子α(TNF-α)等促炎因子的合成,具有显著抗炎效应。但是,阿托伐他汀抗炎效应的具体机制还未完全阐明。本文综述了Toll样受体(TLR)、炎性体、microRNA(miRNA)、小G蛋白和过氧化体增殖物激活型受体(PPAR)在阿托伐他汀抗炎效应中的作用,为深入认识阿托伐他汀的抗炎机制提供了依据。

植物小G蛋白的研究进展

小G蛋白(small GTPases)是近年来细胞信号转导的研究热点,包括Ras、Rho、Rab、Arf和Ran等5个亚家族.植物中存在一种特殊的小G蛋白ROP(Rho-related GTPase from plants)是Rho家族成员,在调控细胞生长发育及植物防御反应体系的建立等方面起重要作用.在植物细胞中ROP存在两种形式,一种是与GTP结合的激活态,另一种是与GDP结合的非激活态,通过这种激活态与非激活态之间的转变,ROPs作为植物生长发育过程中重要的分子开关"参与调控多种信号转导过程.本文主要对国内外近年来有关小G蛋白的种类及其调节机制,以及植物小G蛋白ROP在花粉管生长、根毛发育、H2O2的产生、脱落酸(ABA)以及防御应答反应中的调节作用等方面的研究进展进行综述.

百脉根小G蛋白Rac1基因的克隆与功能分析

小G蛋白Rop在植物细胞信号转导中发挥着重要的分子开关功能。该实验通过RT-PCR方法克隆了百脉根的一个Rop编码基因LjRac1,并对LjRac1基因序列进行生物信息学分析,然后采用半定量RT-PCR检测LjRac1基因在百脉根不同组织中的表达,用荧光实时定量PCR方法检测百脉根接种根瘤菌后LjRac1基因在不同阶段根系中的表达,构建过表达重组质粒,利用发根农杆菌介导的遗传转化法对LjRac1基因功能进行分析。结果表明:(1)序列分析显示,LjRac1完整编码区的cDNA序列长度为594bp,编码197个氨基酸,其编码蛋白具有典型的Rop家族保守结构域;同源分析显示,百脉根LjRac1与大豆GmRac1、野大豆GsRac1的一致性最高(94.42%)。(2)LjRac1基因在百脉根的根、茎、叶、根瘤和花中均有表达,且在根和根瘤中的表达水平较高;接种根瘤菌0.5h后,LjRac1基因在根系中的表达量呈显著升高趋势。(3)过表达转基因植株中LjRac1mRNA的表达水平为对照植株的14.3倍,且过表达植株的结瘤数目较对照明显增加。研究认为,LjRac1基因是一个受根瘤菌诱导增强表达的基因,过表达LjRac1基因可以引起植株结瘤数目的增加,说明LjRac1基因可能参与早期结瘤信号转导途径,从而在根瘤的发育中发挥一定作用。

植物小G蛋白研究进展

小G蛋白是和异三聚体G蛋白α亚基偶联的单体鸟苷酸结合蛋白,所有的小G蛋白从属于Ras超家族.植物小G蛋白超家族尤其是ROP家族在信号转导及生长发育中起了重要的"分子开关"作用,它们参与调控花粉管的伸长、根毛的发育及激素信号转导等过程.主要介绍了小G蛋白的种类、调节机制、ROP家族的功能及靶物,旨在揭示植物小G蛋白功能的多样性.

植物小G蛋白功能的研究进展

近年来,小G蛋白的调控途径已经成为人们研究细胞信号转导过程的热点问题。小G蛋白家族包括Ras、Rab、Rho、Arf和Ran亚家族,它们起着许多不同的重要细胞生理作用,例如基因表达、细胞骨架重组装、微管的形成以及囊泡和核孔运输机制。这些小G蛋白作为重要的分子开关,具有一个非常保守的功能区域,即I-IV结构区,它起着关键性作用。从拟南芥(Arabidopsisthaliana)基因组预测分析得出,拟南芥含有93个小G蛋白同源序列,包含Rab、Rho、Arf和Ran亚家族,但没有Ras亚家族。本文主要阐述了迄今在植物中研究小G蛋白各个亚家族功能的最新进展,并对植物、酵母和动物相关的同源蛋白的生理功能进行比较和推测。

橡胶树HbRAN1基因的克隆与表达分析

利用本课题组获得的二代测序(FLX454)转录组数据库,筛选并克隆获得到1条969 bp的核苷酸序列,该序列编码1个由221个氨基酸组成的25.11 ku蛋白,氨基酸同源性分析发现,此氨基酸序列具有GTPase活性区域,属于小G蛋白RAN亚家族,且与蓖麻、烟草、水稻、小麦等的RAN1基因序列高度同源,命名为HbRAN1(GenBank登录号:KC577150)。实时荧光定量PCR分析结果表明,该基因受割胶、伤害、高温、低温、干旱及乙烯利等因素调控,同时其表达模式与橡胶树死皮程度相关,但对SA、GA、JA、ABA、CTK、2,4-D等激素处理应答不明显。结果表明,HbRAN1基因编码1个典型的RAN蛋白,可能在橡胶树抗逆过程中起作用,可作为橡胶树抗逆分子育种的靶标基因。

δ-catenin与Cdc42在非小细胞肺癌中表达的相关性

背景与目的:δ-catenin是p120 catenin亚家族中的成员,可与细胞膜上的E-cadherin直接结合,形成E-cadherin/catenin复合体。δ-catenin还可以通过调节Cdc42(Small GTP酶)活性以影响细胞骨架装配。该研究检测非小细胞肺癌(non-small cell lung cancer,NSCLC)中δ-catenin及Cdc42的表达情况并探讨了二者表达的相关性。方法:采用免疫组织化学方法检测122例NSCLC标本中δ-catenin与Cdc42的表达。采用蛋白[质]印迹法(Western blot)及逆转录聚合酶链反应(reverse transcription polymerase chain reaction,RT-PCR)法检测肺癌组织中δ-catenin及Cdc42的蛋白及m RNA表达情况。在肺癌细胞系中,分别上调或干扰δ-catenin的表达后,利用G-LISA及Transwell小室法检测Cdc42活性以及肺癌细胞侵袭能力的改变。结果:δ-catenin和Cdc42在肺癌组织中其蛋白及m RNA表达明显高于正常肺组织。而在122例NSCLC病例中,δ-catenin阳性表达率为65.57%(80/122),Cdc42过表达率为68.03%(83/122)。δ-catenin阳性表达和Cdc42的过表达具有较好的相关性(P<0.001)。δ-catenin和Cdc42的协同表达与肺癌的高临床分期、低分化、病理类型为腺癌和淋巴结转移相关(P<0.05),并且与肺癌患者的不良预后明显相关。在肺癌细胞系中通过调节δ-catenin表达,改变Cdc42的表达及活性,影响肺癌细胞的侵袭能力。结论:在肺癌组织中δ-catenin和Cdc42的表达具有相关性,而二者协同表达与患者不良预后相关。

植物生长素极性运输调控机理的研究进展

生长素极性运输特异地调控植物器官发生、发育和向性反应等生理过程。本文综述和分析了生长素极性运输的调控机制。分子遗传和生理学研究证明极性运输这一过程是由生长素输入载体和输出载体活性控制的。小G蛋白ARF附属蛋白GEF和GAP分别调控输出载体(PIN1)和输入载体(AUX1)的定位和活性,并影响高尔基体等介导的细胞囊泡运输系统,小G蛋白ROP也参与输出载体PIN2活性的调节。本文基于作者的研究工作提出小G蛋白在调控生长素极性运输中的可能作用模式。

药用模式真菌灵芝小G蛋白基因家族的系统性分析

[目的]利用比较基因组学方法,对药用模式真菌灵芝的基因组中的小G蛋白基因家族成员进行系统的预测分析和比较。[方法]利用真菌物种中已经报道的小G蛋白,对灵芝全基因组进行BLAST分析,筛选出所有灵芝的小G蛋白基因,并分析这些同源小G蛋白的基本特性。通过小G蛋白家族的进化树分析和功能域分析,解析灵芝小G蛋白家族成员的进化关系。设计每一个小G蛋白同源基因的特异性引物,通过实时荧光定量PCR检测小G蛋白同源基因的表达。[结果]在灵芝中发现了29个小G蛋白家族基因,其中Ras亚家族4个,Rho亚家族4个,Rab亚家族12个,Arf亚家族7个,Ran亚家族1个,还有1个线粒体小G蛋白。菌丝体中有28个小G蛋白基因表达。[结论]根据真菌中已知的小G蛋白系统性地分析了灵芝的小G蛋白家族成员,进行灵芝小G蛋白的特性分析和基因实时荧光定量PCR检测,为下一步研究灵芝小G蛋白家族成员的功能奠定基础。