Amino acid residue 184 of yeast Hsp104 chaperone is critical for prion-curing by guanidine, prion propagation, and thermotolerance
Amino acid residue 184 of yeast Hsp104 chaperone is critical for prion-curing by guanidine, prion propagation, and thermotolerance
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DOI：
10.1073/pnas.152333299
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发表时间：
2002-07-23
影响因子：
11.1
通讯作者：
Masison, DC
中科院分区：
文献类型：
--
作者：
Jung, GM;Jones, G;Masison, DC
胍对Hsp 104的灭活被认为是胍治愈酵母朊病毒的机制。我们现在发现了一个Hsp104突变（D184N），赋予抗性胍固化的酵母[PSI+]朊病毒。在一个独立的筛选中，我们分离出了一个HSP 104等位基因，该等位基因在相同的残基（D184 Y）中发生了改变，该残基以温度依赖性方式显著损害[PSI+]的传播。HSP104的定向诱变产生额外的等位基因，赋予不同程度的抗性胍固化或受损[PSI+]的传播。这些突变同样影响了[URE3]朊病毒的繁殖。所有突变蛋白的基础和诱导丰度是正常的。表达突变体蛋白的细胞的耐热性是对胍的耐药性，并且耐热性的程度与[PSI+]稳定性无关。因此，我们表明，胍治愈酵母朊病毒灭活热休克蛋白104，并确定一个高度保守的热休克蛋白104残基，是关键的酵母朊病毒的繁殖。我们的数据表明，热休克蛋白104的活性可以大大降低，而不影响[PSI+]的稳定性，和热休克蛋白104与朊病毒聚集体的相互作用不同，而不是与热变性蛋白质的聚集体。
inactivation of Hsp104 by guanidine is contended to be the mechanism by which guanidine cures yeast prions. We now find an Hsp104 mutation (D184N) that confers resistance to guanidine-curing of the yeast [PSI+] prion. In an independent screen we isolated an HSP104 allele altered in the same residue (D184Y) that dramatically impairs [PSI+] propagation in a temperature-dependent manner. Directed mutagenesis of HSP104 produced additional alleles that conferred varying degrees of resistance to guanidine-curing or impaired [PSI+] propagation. The mutations similarly affected propagation of the [URE3] prion. Basal and induced abundance of all mutant proteins was normal. Thermotolerance of cells expressing mutant proteins was variably resistant to guanidine, and the degree of thermotolerance did not correlate with [PSI+] stability. We thus show that guanidine cures yeast prions by inactivating Hsp104 and identify a highly conserved Hsp104 residue that is critical for yeast prion propagation. Our data suggest that Hsp104 activity can be reduced substantially without affecting [PSI+] stability, and that Hsp104 interacts differently with prion aggregates than with aggregates of thermally denatured protein.