几种热激蛋白在细胞凋亡信号通路中的调控作用

热激蛋白(heat shock proteins, HSPs)作为进化保守的蛋白家族 之一,普遍存在于各种生物体中,并在生物体内发挥着重要的生理功能.大 量的实验证据表明,热激蛋白与细胞凋亡密切相关,参与细胞凋亡信号通 路的多个环节. 近年来有关该领域的研究已获得了重要的突破与进展.一方 面,热激蛋白主要起着抑制细胞凋亡、促进细胞存活的作用;另一方面, 某些热激蛋白又能够作为凋亡蛋白的分子伴侣,促进细胞凋亡,比如HSP70 能够激活DNase来促使细胞凋亡,线粒体内HSP60能够促进caspase依赖的细 胞凋亡途径.本文在阐明细胞凋亡信号通路的基础上,综述了近年来几种不 同热激蛋白家族（HSP90、 HSP70 、HSP60和小分子HSPs）在细胞凋亡调控 中作用的研究进展,重点阐述了几种主要热激蛋白与细胞凋亡信号通路上 相关因子的相互作用,并绘制了热激蛋白在细胞凋亡信号通路中的调控图 ,为进一步完善细胞凋亡调控网络研究提供一定的参考.     

热激蛋白ClpB的结构和功能

ClpB是HSP100／Clp蛋白家族的一员,具有分子伴侣功能,通过溶解热胁迫下的蛋白聚集体,减少热激对细胞的伤害,ClpB与细胞的耐热性紧密相关。近年来,ClpB在植物中的功能成为研究的热点,但大多局限在植物胞质ClpB的研究,而对细胞器ClpB的研究较少。文章介绍了热激蛋白ClpB的结构、功能和植物热激蛋白ClpB的研究现状。     

钙-钙调素信号系统参与热激信号转导的研究

根据作者实验室的研究工作结合国内外的研究动态讨论热激信号转导的Ca2 -CaM途径。作者实验室的工作表明,钙一钙调素(Ca^2 -CaM)信号系统参与植物热激信号转导。激光共聚焦扫描显微镜的观察结果表明,37℃热激可引起小麦胞内自由Ca。’浓度迅速提高。在Ca^2 存在条件下,热激也引起小麦CaM基因CaM1-2表达及CaM蛋白含量增加。Ca^2 可促进小麦热激基因hsp26和mp70表达和热激蛋白合成,而Ca^2 螯合剂EGTA、Ca^2 通道阻断剂异搏定和LaCl3、CaM抑制剂W7、TFP和CPZ明显降低热激基因hsp26和mp70表达和热激蛋白合成。EGTA、异搏定、TFP或CPZ也阻止小麦耐热性的获得。小麦CaM基因与热激基因的表达动力学研究表明CaM位于热激信号转导的上游,而Ca^2 是启动热激反应的胞内关键因子。凝胶阻滞分析的结果表明,Ca^2 -CaM在热激信号转导中的作用是通过激活热激转录因子的DNA结合活性来实现的。根据大量实验证据,作者提出在植物细胞内存在一条新的热激信号转导途径——钙一钙调素途径。     

p38蛋白激酶在热损伤诱导单核细胞Raw264.7凋亡中的作用

为探讨ｐ３８蛋白激酶在热损伤诱导单核细胞株Ｒａｗ ２６４．７凋亡中的调控作用．应用流式细胞检测术、透射电镜技术、ＤＮＡ 凝胶电泳、Ｗｅｓｔｅｒｎ ｂｌｏｔ、激酶活性测定检测ｐ３８蛋白激酶在热损伤诱导细胞凋亡中的作用．结果显示,热损伤后５ ｍ ｉｎ,ｐ３８即被激活,３０ ｍ ｉｎ 时达到最高水平,然后逐渐下降,２ ｈ 达基底水平;热损伤后３ ｈ 细胞凋亡率开始明显增高,ｐ３８蛋白激酶活性增高是细胞凋亡发生之前的事件;进一步观察了ｐ３８特异性抑制剂ＦＨＰＩ对细胞凋亡的影响,发现ＦＨＰＩ可以抑制热损伤诱导的细胞凋亡．上述结果提示,ｐ３８参与介导热损伤诱导的Ｒａｗ ２６４．７细胞凋亡．     

热疗通过上调基因PUMA表达诱导胃癌MKN45凋亡

目的探讨热疗诱导胃癌MKN45细胞凋亡及其对胃癌细胞促凋亡蛋白PUMA表达的影响。方法体外复苏与培养人胃癌MKN45细胞。对照组常温(37℃)下培养,实验组按不同时间分组43℃水浴加热胃癌MKN45后培养24h,采用倒置显微镜和透射电镜观察热疗后胃癌细胞的形态结构变化。四甲基偶氮唑盐比色法(MMT)检测细胞增殖抑制。AO/EB荧光双染色法及Annexin-V/PI双染色法流式检测细胞凋亡。Western blot检测促凋亡蛋白PUMA蛋白表达。结果光镜观察发现热疗后MKN45细胞明显皱缩、变圆及细胞漂浮,3h多数细胞漂浮。电镜下可见热疗后MKN45细胞核仁增多,胞核及胞浆出现大小不等的空泡和凋亡小体。MTT实验提示,热疗可明显抑制MKN45细胞生长(P0.01)。AO/EB荧光双染色显示,热疗后细胞呈淡黄或橘红色,胞核呈现致密斑状。热疗0.5h、1h、2h和3h后,AO/EB荧光双染色法及Annexin-V/PI双染色法流式检测细胞凋亡率基本一致。热疗0.5h后细胞凋亡率明显增高,1h略低于0.5h,2h达最高峰。Western blot显示,MKN45细胞各热疗时间的PUMA蛋白表达明显升高,热疗0.5h开始升高,热疗2h达最高峰,1h略低于0.5h,3h有所回落(P0.05)。结论热疗2h诱导胃癌细胞凋亡的效果最佳,并且可通过上调基因PUMA表达诱导胃癌MKN45凋亡。     

热激蛋白70研究进展

热激蛋白70（HSP70）是广泛存在且高度保守的蛋白,作为伴侣分子能够促进蛋白折叠;HSP70可以通过阻止细胞色素c从线粒体释放,与凋亡诱导因子结合使其不能入核,或者抑制JNK激酶活性调节细胞凋亡;HSP70可以调节细胞周期进程,促进细胞生长,阻止细胞衰老;免疫功能研究表明HSP70是有效的免疫佐剂,可激发抗原特异性的CTL反应,同时细胞外HSP70和膜结合HSP70可激发非特异性免疫反应。     

水稻热休克转录因子OsHSF13的克隆与生物信息学的初步分析(简报)

环境刺激的信号转导是植物信号转导的一个重要研究方向。热激反应(heat-shockresponse,HSR)是动植物细胞或器官在遇到外界热刺激时所产生的一种保护性反应,是正常的蛋白质合成受阻时产生热激蛋白(heat-shockprotein,HSP)的一种细胞生理活动,其表达通过热休克转录因子(heat-shock factor,HSF)来进行调控[1]。编码热激蛋白基因的启动子区域存在着一段保守的DNA序列,是热休克转录因子的结合位点(heat-shockelement,HSE)。当植物受到外界的热刺激时,HSF可以与HSE特异性结合,激活热激蛋白基因的表达,     

细胞凋亡中的钙调节

胞质Ca^2 升高是细胞凋亡中Ca^2 调节的经典模式,但近年来有证据表明胞质Ca^2 下降同样能诱导细胞凋亡,目前研究发现,胞内Ca^2 在细胞质,细胞核以及细胞钙库线粒体和内质网的动态平衡破坏和重新分布直接参与细胞凋亡信号的调控,而Bcl-2家族蛋白在细胞凋亡过程的胞内Ca^2 调节及继后的一系列生理效应中发挥特殊作用。细胞凋亡中Ca^2 调节的深入研究不但有助于阐明细胞凋亡的调控机理,同时为相关疾病防治和药物开发提供新的策略。     

果蝇热激蛋白的研究进展

热休克蛋白(heat shock proteins,HSPs)是生物体受到应激刺激时诱导产生的一组保守性蛋白,普遍存在于各种生物体中。近年来,果蝇Drosophila作为生命科学与人类疾病研究的重要模式生物,其热激蛋白的研究取得了许多新的进展。文章对果蝇热激蛋白的类别、热激蛋白基因的表达调控机制、热激蛋白的分子伴侣功能、调节细胞存亡和影响发育及寿命等相关生物学功能进行综述,并对热激蛋白在神经退行性疾病治疗中的应用前景作展望。     

热激蛋白27的性质及生理功能

热激蛋白（heat shock protein,HSP）是广泛存在于生物体内、在生物进化过程中序列高度保守的蛋白质家族。HSP27是HSP家族中的重要一员,在机体应激的情况下表达增加,通过分子伴侣作用、抗细胞凋亡和抗氧化应激等作用保护细胞,同时HSP27与多种临床疾病密切相关。     

Heat shock proteins in hematopoietic malignancies

Inducible heat shock proteins are molecular chaperones whose expression is increased after many different types of stress. They have a protective function helping the cell to cope with lethal conditions. Their basal expression is low in nonstressed, normal and nontransformed cells. However, in cancer cells and particularly in hematological malignancies, they are surprisingly abundant. Malignant cells have to rewire their metabolic requirements and therefore have a higher need for chaperones. This cancer cell addiction for HSPs is the basis for the use of HSP inhibitors in cancer therapy. HSPs have been shown to interact with different key apoptotic proteins. As a result, HSPs can essentially block the apoptotic pathways at several steps, most of them involving the activation of cystein proteases called caspases. Apoptosis and differentiation are physiological processes that share many common features, for instance, a controlled caspase activation and chromatin condensation are frequently observed. It is, therefore, not surprising that HSPs may be implicated in the differentiation process. HSPs may determine the fate of the cells by orchestrating the decision of apoptosis versus differentiation. This review will focus on the role of HSPs in hematological malignancies and the emerging therapeutic options that are being either proposed or used to target these protective proteins.     

Apoptosis Versus Cell Differentiation

Heat shock proteins HSP27, HSP70 and HSP90 are molecular chaperones whose expression is increased after many different types of stress. They have a protective function helping the cell to cope with lethal conditions. The cytoprotective function of HSPs is largely explained by their anti-apoptotic function. HSPs have been shown to interact with different key apoptotic proteins. As a result, HSPs can block essentially all apoptotic pathways, most of them involving the activation of cystein proteases called caspases. Apoptosis and differentiation are physiological processes that share many common features, for instance, chromatin condensation and the activation of caspases are frequently observed. It is, therefore, not surprising that many recent reports imply HSPs in the differentiation process. This review will comment on the role of HSP90, HSP70 and HSP27 in apoptosis and cell differentiation. HSPs may determine de fate of the cells by orchestrating the decision of apoptosis versus differentiation.     

Apoptosis Versus Cell Differentiation: Role of Heat Shock Proteins HSP90, HSP70 and HSP27

Heat shock proteins HSP27, HSP70 and HSP90 are molecular chaperones whose expression is increased after many different types of stress. They have a protective function helping the cell to cope with lethal conditions. The cytoprotective function of HSPs is largely explained by their anti-apoptotic function. HSPs have been shown to interact with different key apoptotic proteins. As a result, HSPs can block essentially all apoptotic pathways, most of them involving the activation of cystein proteases called caspases. Apoptosis and differentiation are physiological processes that share many common features, for instance, chromatin condensation and the activation of caspases are frequently observed. It is, therefore, not surprising that many recent reports imply HSPs in the differentiation process. This review will comment on the role of HSP90, HSP70 and HSP27 in apoptosis and cell differentiation. HSPs may determine de fate of the cells by orchestrating the decision of apoptosis versus differentiation.Key Words: apoptosis, differentiation, heat shock proteins, chaperones, cancer cells, anticancer drugs     

Heat shock protein 70 (Hsp70): membrane location, export and immunological relevance

Stress or heat shock proteins (HSPs) are remarkably conserved in all living organisms. Their expression is induced in response to a variety of physiological and environmental insults. In the cytosol these proteins play an essential role as molecular chaperones by assisting the correct folding of nascent and stress-accumulated misfolded proteins, preventing protein aggregation, transport of proteins, and supporting antigen processing and presentation. Following stress, intracellularly located HSPs fulfill protective functions and thus prevent lethal damage. In contrast, membrane-bound or extracellularly located HSPs act as danger signals and elicit immune responses mediated either by the adaptive or innate immune system. Here, HSPs act as carriers for immunogenic peptides, induce cytokine release or provide recognition sites for natural killer (NK) cells. This article will discuss methods for the detection of membrane-bound and extracellular HSPs and methods for determining their immunological functions.     

Heat shock proteins: essential proteins for apoptosis regulation

Many different external and intrinsic apoptotic stimuli induce the accumulation in the cells of a set of proteins known as stress or heat shock proteins (HSPs). HSPs are conserved proteins present in both prokaryotes and eukaryotes. These proteins play an essential role as molecular chaperones by assisting the correct folding of nascent and stress-accumulated misfolded proteins, and by preventing their aggregation. HSPs have a protective function, that is they allow the cells to survive to otherwise lethal conditions. Various mechanisms have been proposed to account for the cytoprotective functions of HSPs. Several of these proteins have demonstrated to directly interact with components of the cell signalling pathways, for example those of the tightly regulated caspase-dependent programmed cell death machinery, upstream, downstream and at the mitochondrial level. HSPs can also affect caspase-independent apoptosis-like process by interacting with apoptogenic factors such as apoptosis-inducing factor (AIF) or by acting at the lysosome level. This review will describe the different key apoptotic proteins interacting with HSPs and the consequences of these interactions in cell survival, proliferation and apoptotic processes. Our purpose will be illustrated by emerging strategies in targeting these protective proteins to treat haematological malignancies.     

Heat shock proteins,cellular chaperones that modulate mitochondrial cell death pathways

Stress or heat shock proteins (HSPs) are ubiquitous and highly conserved proteins whose expression is induced in response to a wide variety of physiological and environmental insults. They allow the cells to survive to otherwise lethal conditions. Various mechanisms have been proposed to account for the cytoprotective functions of HSPs. These proteins play an essential role in intracellular "house-keeping" by assisting the correct folding of nascent and stress-accumulated misfolded proteins and preventing their aggregation. Several HSPs have also demonstrated to directly interact with various components of the tightly regulated programmed cell death machinery, upstream, and downstream of the mitochondrial events. Finally, HSPs could play a role in the proteasome-mediated degradation of selected proteins under stress conditions. Altogether, these properties could make HSPs appropriate targets for modulating cell death pathways.     

植物热激蛋白的功能及其基因表达的调控

本文介绍了植物热激蛋白的产生、分布和分类。着重论述了热激反应的特点、植物热激蛋白的功能、热激基因表达与调控的研究进展     

Cell stress and implications of the heat-shock response in skin

Heat-shock proteins (HSPs), or so-called stress proteins may play an important role in cutaneous pathophysiology. HSPs are a group of highly conserved molecules that are expressed by all cells when subjected to heat or other forms of physical or chemical stress. The physiological roles of stress proteins are varied and are important in stress and nonstress conditions. They bind to other cellular proteins and participate in protein folding pathways during stress and also during the synthesis of new polypeptides. HSPs are also essential for thermotolerance and for prevention and repair of damage caused in DNA after ultraviolet exposure. Although HSPs are expressed in the skin in both epidermis and dermis, HSPs may influence many other cellular processes in the inflammatory and immune skin response. Many authors have speculated on a link between HSPs and human skin disease characterized by inflammation and proliferation.Abbreviations HSP heat-shock protein - IL-1 interleukin-1     

Heat Shock Proteins in Tobacco Cell Suspension during Growth Cycle

Tobacco (Nicotiana tabacum L. cv Wisconsin 38) cells grown in suspension culture at 26°C produce heat shock proteins (HSPs) when exposed to elevated temperature of 34 to 42°C. At 34 and 38°C, synthesis of normal proteins is maintained while HSPs are expressed within 30 minutes after initiation of the shock. At 42°C, HSPs are still expressed but normal proteins are made at a reduced rate or not at all. Exposure of cells to 38°C allows for a full expression of HSPs without inhibition of the synthesis of normal proteins. Induced synthesis of HSPs at 38°C is maximal 1 to 2 hours after elevation of temperature and diminishes thereafter through at least 6 hours. Cells growing asynchronously in the logarithmic phase of growth produce HSPs at a much higher rate than those in the stationary phase. The ability to synthesize HSPs disappears about one generation time before the cells reach a growth plateau.     

In vitro reconstitution of heat shock protein-peptide complexes for generating peptide-specific vaccines against cancers and infectious diseases

Known commonly as molecular chaperones for proteins, heat shock proteins (HSPs) have also been found to chaperone small molecular weight cellular peptides. HSP-peptide complexes can prime T cell immunity specific against the peptides bound to HSPs, but not against HSPs per se. This immunomodulatory functions of HSPs are based on two intrinsic properties. One, HSPs are excellent adjuvants due to their ability to activate dendritic cells (DCs). Two, HSPs can bind directly to their receptors on DCs to then channel HSP-associated peptides to associate with MHC molecules. When a specific antigenic peptide is defined, this peptide can also be complexed with either tissue derived or recombinant HSPs in vitro to generate HSP-peptide complexes as peptide-specific vaccines. This article focuses on the methods commonly used to reconstitute HSP-peptide complexes, and discusses assays to verify the efficiency of complexing for immunotherapy against cancers and infectious diseases.