热激蛋白HSP

The introduction of truncated genes into mammalian cells, or treatment with amino acid analogues, will result in the synthesis of aberrant proteins. Other treatments, such as heat or ethanol, may damage cell proteins by denaturation, or by mechanisms involving free radicals. Aberrant or damaged proteins are then recognized by the ATP-requiring ubiquitindependent degradation system. However, a suggestion is that the normally 'inactive' form of heat shock transcription factor (HSTF) is in an ubiquitinated state; thus the depletion of the cellular levels of free ubiquitin due to any increases in levels of aberrant or damaged protein will lead to a rise in the levels of nonubiquitinated HSTF. This may be the 'active' form. Alternatively, other mechanisms which do not involve ubiquitin may bring Possible means whereby the presence of damaged about the structural alteration of' inactive' cellular proteins might signal the induction of hsp HSTF to 'active' HSTF (e.g. denaturation, free gene transcription radical damage, proteolytic cleavage).
What are the heat shock proteins (HSPs)?
Prokaryotic and eukaryotic cells respond potentially harmful stimulations like heat stress by inducing synthesis of stress proteins so called heat shock proteins( Hsps).
Introduction
Ferruccio Ritossa(1936-2014 ,1,9)
Ferruccio Ritossa:scientist and sculptor of Italy. After graduating in Agricultural Sciences at the University of Bologna in 1959, he carried out his studies on Genetics in Pavia and then in Naples at IIGB and in the United
基因转录，相应生成了一系列分子量为70kDa和26kDa的蛋白质，这些蛋白质 被命名为热休克蛋白质（Heat shock protain,HSPs） 。 1982 年在冷泉港召开了第1届HSPs的国际大会。之后对HSPs的研究日益 增多，20世纪80年代后期研究进入分子水平。
1992 年 Horwitz 提 出 HSPs 是 一 种 分 子 伴 侣 (Molecular chaperonims )的理论。近几十年来发现某些HSPs具有分子伴侣的作用后，
HEAT SHOCK PROTEINS
By
Wu Chang kui
Content
Introduction Stimulations Molecular regulation of HSPs Classification of HSPs Evolution of HSPs Function of HSPs Reference
Among his major achievements is the discovery of the Heat Shock response in Drosophila. In 1962 someone at the Genetics Institute in Pavia, Italy, turned up the temperature in an incubator holding fruit flies. When Ferruccio Ritossa, then a young geneticist, examined the cells of these “heat shocked” flies, he noticed that their chromosomes had puffed up at discrete locations. The puffy appearance was a known sign that genes were being activated in those regions to give rise to their encoded proteins, so those sites of activity became known as the heat shock loci.
使HSPs的研究产生了一次飞跃。目前HSPs的作用和功能已经引起世界各国学 者的广泛关注。
Why molecular chaperonims?
Molecular chaperons are a class of proteins that function to minimize the problems that arise when other proteins are in nonnative conformations. Molecular chaperons can recognize and bind to nonnative and release them in highly related fashion, allowing the bound proteins to attain/reattain their native conformation and/or be targeted for degradation and removal from the cell. Chaperons are responsible for protein folding, assembly, translocation and degradation in many cellular processes. They stabilize proteins and membranes and can assist in protein refolding under stress conditions.
Heat shock proteins (HSPs) are a large class of family proteins that have been highly conserved throughout evolution and exist by prokaryote and eukaryote organisms.
Drosophila. Experientia 1velopment of Heat Shock Protein
1962年Ritossa首先在果蝇上发现热休克（Heat chock）现象。 1974年Tissieres研究证实该现象的产生是因为温度高增强了这一区域的
HSPs are found in virtually all living organisms, from bacteria to humans, but Archaea.
Stimulations
How does heat stress affect Organism?
Sensing heat at the plasma membrane
Ritossa F (1962) A new puffing pattern induced by temperature shockand DNP in
Ferruccio Ritossa looking at chromosomal puffs in his laboratory in the early 1960s.
Molecular regulation of HSPs
There is an analog situation in eukaryotes. Expression of Hsp genes are primarily regulated at transcriptional level. Heat shock response is controlled by heat shock transcription factors (HSF) binding to specific DNA sites (HS elements) at transcriptional level. HSF specifically binds to heat shock elements (HSEs) in promoters and activates the transcription of HS genes. HSFs, once plant has sensed an increase in temperature, go from a monomeric state in the cytoplasm to a trimeric state in the cell nucleus where they can bind the HSEs. HSF binding recruits other transcription components, resulting in gene expression within minutes.
A possible mechanism involving transcription factors whereby hsp genes might be activated.
Roy H. B.Heat chock and the heat shock proteins. Biochem. J. (1986) 240, 313-324.
Heat stress-induced activation of HSF1
Richard l. Morimoto.Cell in stress :transcriptional activation of heat shock genes . 1993.Science,259.1409-1450.
States.
After teaching Genetics at the Universities of Bari and Bologna, in 1992 he decided to leave the Academy and devote himself to Sculpture.
Discovery and development of Heat Shock Protein