Hsp42 is the general small heat shock protein in the cytosol of Saccharomyces cerevisiae
Hsp42 is the general small heat shock protein in the cytosol of Saccharomyces cerevisiae
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DOI：
10.1038/sj.emboj.7600080
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发表时间：
2004-02-11
期刊：
影响因子：
11.4
通讯作者：
Buchner, J
中科院分区：
文献类型：
--
作者：
Haslbeck, M;Braun, N;Buchner, J
小分子热休克蛋白（Small heat shock proteins，sHsps）是一种广泛存在的防止蛋白质非特异性聚集的分子伴侣。到目前为止，Hsp26是酿酒酵母中唯一明确鉴定的sHsp家族成员。本研究表明，在S.酿酒酵母由两种蛋白质Hsp26和Hsp42组成。Hsp42形成具有桶状结构的大的动态寡聚体。与主要在热休克温度下起作用的Hsp26相反，Hsp42在体内和体外测试的所有条件下作为伴侣是有活性的。在热休克条件下，热休克蛋白42和热休克蛋白26抑制三分之一的细胞溶质蛋白的聚集。该亚群与Hsp42和Hsp26约90%重叠。sHsp底物属于不同的生化途径。这表明sHsps对S.啤酒。与该观察结果一致，sHsp敲除菌株显示表型缺陷。两者合计，我们的研究结果定义热休克蛋白42作为一个重要的球员在生理和应激条件下的蛋白质稳态。
Small heat shock proteins (sHsps) are ubiquitous molecular chaperones that prevent the unspecific aggregation of proteins. So far, Hsp26 was the only unambiguously identified member of the sHsp family in Saccharomyces cerevisiae. We show here that the sHsp system in the cytosol of S. cerevisiae consists of two proteins, Hsp26 and Hsp42. Hsp42 forms large dynamic oligomers with a barrel-like structure. In contrast to Hsp26, which functions predominantly at heat shock temperatures, Hsp42 is active as a chaperone under all conditions tested in vivo and in vitro. Under heat shock conditions, both Hsp42 and Hsp26 suppress the aggregation of one-third of the cytosolic proteins. This subset is about 90% overlapping for Hsp42 and Hsp26. The sHsp substrates belong to different biochemical pathways. This indicates a general protective function of sHsps for proteome stability in S. cerevisiae. Consistent with this observation, sHsp knockout strains show phenotypical defects. Taken together, our results define Hsp42 as an important player for protein homeostasis at physiological and under stress conditions.