热激蛋白70与热激反应

热激反应是细胞保护的最原始机制之一。近年来,越来越多的研究证明热激蛋白作为一种自然机制参与细胞保护,而热激蛋白70家族在其中起重要作用,从而成为恶劣条件、手术过程以及同病原体的斗争中器官保护的重要机制之一。     

热激蛋白90与热激应答

热激蛋白90(heat shock protein 90,HSP90)作为机体重要的分子伴侣之一,主要是维持机体内环境的稳态.在机体遭受内外界刺激时,体内氧化-抗氧化平衡失调诱发机体热激应答,诱导HSP90高表达来抵御刺激对机体造成的损伤.     

Heat Shock Response in Lactobacillus plantarum

Heat stress resistance and response were studied in strains of Lactobacillus plantarum. Stationary-phase cells of L. plantarum DPC2739 had decimal reduction times (D values) (D value was the time that it took to reduce the number of cells by 1 log cycle) in sterile milk of 32.9, 14.7, and 7.14 s at 60, 72, and 75°C, respectively. When mid-exponential-phase cells were used, the D values decreased. The temperature increases which caused a 10-fold reduction in the D value ranged from 9 to 20°C, depending on the strain. Part of the cell population treated at 72°C for 90 s recovered viability during incubation at 7°C in sterile milk for 20 days. When mid-exponential- or stationary-phase cells of L. plantarum DPC2739 were adapted to 42°C for 1 h, the heat resistance at 72°C for 90 s increased ca. 3 and 2 log cycles, respectively. Heat-adapted cells also showed increased growth at pH 5 and in the presence of 6% NaCl. Two-dimensional gel electrophoresis of proteins expressed by control and heat-adapted cells revealed changes in the levels of expression of 31 and 18 proteins in mid-exponential- and stationary-phase cells, respectively. Twelve proteins were commonly induced. Nine proteins induced in the heat-adapted mid-exponential- and/or stationary-phase cells of L. plantarum DPC2739 were subjected to N-terminal sequencing. These proteins were identified as DnaK, GroEL, trigger factor, ribosomal proteins L1, L11, L31, and S6, DNA-binding protein II HlbA, and CspC. All of these proteins have been found to play a role in the mechanisms of stress adaptation in other bacteria. Antibodies against GroES detected a protein which was induced moderately, while antibodies against DnaJ and GrpE reacted with proteins whose level of expression did not vary after heat adaptation. This study showed that the heat resistance of L. plantarum is a complex process involving proteins with various roles in cell physiology, including chaperone activity, ribosome stability, stringent response mediation, temperature sensing, and control of ribosomal function. The physiological mechanisms of response to pasteurization in L. plantarum are fundamental for survival in cheese during manufacture.     

Response of Higher Plants to Heat Shock

When sorghum seedlings were rapidly shifted from the cultural temperature of 30℃ to 40℃ and 45℃, a set of abnormal proteins, generally referred to as heat shock proteins were induced. They are a group of high molecular weight proteins (about 66–117 kD), a few intermediate molecular weight proteins (33–66kD) and a low molecular weight protein of 18 kD. At the same time, the synthesis of normal proteins was relatively depressed. The res ponse of the shoot tissues of sorghum seedings to heat shock is similar to that of the root tissues, but there are some differences in more detail between the two tissues. The synthesis of heat shock proteins in sorghum seedlings was rapid. After one-hour exposure at 45℃ their synthesis in the roots was detectable. Maximum induction took place in the second hour of exposure, thereafter their synthesis began to decline markedly. Finally, there appear to be some proteins whose synthesis was not supressed during heat shock, It is not yet known why the synthesis of these proteins is so stable.     

Response of Mutant Sunflower Lines to Heat Shock

The effects of heat shock (HS) (40°C for 1 h) on the level of malondialdehyde (MDA), the terminal product of lipid peroxidation, superoxide dismutase (SOD) activity, catalase activity, and total peroxidase activity (TPA) were studied in root meristems and chloroplasts of several sunflower (Helianthus annuusL.) lines that carried nuclear or plastome chlorophyll mutations. HS either lowered or did not affect the MDA level in the root meristem and in the chloroplasts from the first true leaf, as compared to the untreated plants. In both treatments, the root and leaf enzyme activities varied in the sunflower lines. In the root meristem, catalase was the most sensitive to HS, whereas, in the chloroplasts from HS-treated sunflower lines, HS activated either TPA or SOD.     

生物的热休克反应研究进展

介绍了生物应激反应的基本概念、基本知识、研究概况、热休克蛋白的作用及与细胞凋亡的关系。     

The Identification of Protein Kinase C Iota as a Regulator of the Mammalian Heat Shock Response Using Functional Genomic Screens

Background

The heat shock response is widely used as a surrogate of the general protein quality control system within the cell. This system plays a significant role in aging and many protein folding diseases as well as the responses to other physical and chemical stressors.

Methods/Principal Findings

In this study, a broad-based functional genomics approach was taken to identify potential regulators of the mammalian heat shock response. In the primary screen, a total of 13724 full-length genes in mammalian expression vectors were individually co-transfected into human embryonic kidney cells together with a human HSP70B promoter driving firefly luciferase. A subset of the full-length genes that showed significant activation in the primary screen were then evaluated for their ability to hyper-activate the HSP70B under heat shock conditions. Based on the results from the secondary assay and gene expression microarray analyses, eight genes were chosen for validation using siRNA knockdown. Of the eight genes, only PRKCI showed a statistically significant reduction in the heat shock response in two independent siRNA duplexes compared to scrambled controls. Knockdown of the PRKCI mRNA was confirmed using quantitative RT-PCR. Additional studies did not show a direct physical interaction between PRKCI and HSF1.

Conclusions/Significance

The results suggest that PRKCI is an indirect co-regulator of HSF1 activity and the heat shock response. Given the underlying role of HSF1 in many human diseases and the response to environmental stressors, PRKCI represents a potentially new candidate for gene-environment interactions and therapeutic intervention.     

Non-Specific Protein Modifications by a Phytochemical Induce Heat Shock Response for Self-Defense

Accumulated evidence shows that some phytochemicals provide beneficial effects for human health. Recently, a number of mechanistic studies have revealed that direct interactions between phytochemicals and functional proteins play significant roles in exhibiting their bioactivities. However, their binding selectivities to biological molecules are considered to be lower due to their small and simple structures. In this study, we found that zerumbone, a bioactive sesquiterpene, binds to numerous proteins with little selectivity. Similar to heat-denatured proteins, zerumbone-modified proteins were recognized by heat shock protein 90, a constitutive molecular chaperone, leading to heat shock factor 1-dependent heat shock protein induction in hepa1c1c7 mouse hepatoma cells. Furthermore, oral administration of this phytochemical up-regulated heat shock protein expressions in the livers of Sprague-Dawley rats. Interestingly, pretreatment with zerumbone conferred a thermoresistant phenotype to hepa1c1c7 cells as well as to the nematode Caenorhabditis elegans. It is also important to note that several phytochemicals with higher hydrophobicity or electrophilicity, including phenethyl isothiocyanate and curcumin, markedly induced heat shock proteins, whereas most of the tested nutrients did not. These results suggest that non-specific protein modifications by xenobiotic phytochemicals cause mild proteostress, thereby inducing heat shock response and leading to potentiation of protein quality control systems. We considered these bioactivities to be xenohormesis, an adaptation mechanism against xenobiotic chemical stresses. Heat shock response by phytochemicals may be a fundamental mechanism underlying their various bioactivities.     

Heat Shock and Caloric Restriction Have a Synergistic Effect on the Heat Shock Response in a sir2.1-dependent Manner in Caenorhabditis elegans

The heat shock response (HSR) is responsible for maintaining cellular and organismal health through the regulation of proteostasis. Recent data demonstrating that the mammalian HSR is regulated by SIRT1 suggest that this response may be under metabolic control. To test this hypothesis, we have determined the effect of caloric restriction in Caenorhabditis elegans on activation of the HSR and have found a synergistic effect on the induction of hsp70 gene expression. The homolog of mammalian SIRT1 in C. elegans is Sir2.1. Using a mutated C. elegans strain with a sir2.1 deletion, we show that heat shock and caloric restriction cooperate to promote increased survivability and fitness in a sir2.1-dependent manner. Finally, we show that caloric restriction increases the ability of heat shock to preserve movement in a polyglutamine toxicity neurodegenerative disease model and that this effect is dependent on sir2.1.     

雄性不育高粱四种酶在热激过程中的反应

热激时,雄性不育高梁中4种酶的同工酶的变化以细胞色素氧化酶最大,酸性磷酸酯酶次之,淀粉酶第三,酯酶最小,说明不同酶对热激的反应不同,故与育性的关系也有差异。苗期与穗期同工酶谱互不对应,表明酶随发育而改变。不育系的细胞色素氧化酶酶带C5,C8随温度上升而减弱,达40℃时与可育的保持系相似,此现象与不育系的雄蕊在40℃时呈现可育态同时发生,说明此酶带与育性相关。