Interactions of the chaperone Hsp104 with yeast Sup35 and mammalian PrP.
Interactions of the chaperone Hsp104 with yeast Sup35 and mammalian PrP.
复制标题
伴侣 Hsp104 与酵母 Sup35 和哺乳动物 PrP 的相互作用。
DOI：
10.1073/pnas.94.25.13932
复制
发表时间：
1997
影响因子：
11.1
通讯作者：
Lindquist,S
中科院分区：
文献类型：
--
作者：
Schirmer,EC;Lindquist,S
[PSI+] 是酵母中的一种遗传元件，其表型的可遗传变化似乎是由 Sup35 蛋白构象状态的可遗传变化引起的。 [PSI+]的遗传和Sup35体内的物理状态依赖于蛋白伴侣Hsp104（热休克蛋白104）。尽管这些观察结果提供了强有力的遗传论据来支持 [PSI+] 的“仅蛋白质”或“朊病毒”假说，但迄今为止，还没有直接证据表明这两种蛋白质之间存在相互作用。我们报告说，当纯化的 Sup35 和 Hsp104 混合时，圆二色性 (CD) 光谱与通过添加蛋白质的单个光谱预测的光谱不同，并且 Hsp104 的 ATPase 活性受到抑制。使用另外两种淀粉样蛋白生成底物（哺乳动物 PrP 和 β-淀粉样蛋白 1-42 肽）获得了类似的结果，但使用几种对照蛋白则没有获得类似的结果。对于跨越 PrP 蛋白序列的一组肽，那些在 CD 光谱中产生最大变化的肽也会对 Hsp104 中的 ATP 酶活性产生最强的抑制。我们的观察表明 (i) 先前描述的 Hsp104 和 [PSI+] 之间的遗传相互作用是由 Hsp104 和 Sup35 之间的直接相互作用引起的； (ii) Sup35 和 PrP 分别是酵母和哺乳动物朊病毒的决定因子，它们具有共同的结构特征，可导致与 Hsp104 发生特异性相互作用； (iii) 这些相互作用将结构变化与 Hsp104 的 ATP 酶活性结合起来。
[PSI+] is a genetic element in yeast for which a heritable change in phenotype appears to be caused by a heritable change in the conformational state of the Sup35 protein. The inheritance of [PSI+] and the physical state of Sup35in vivodepend on the protein chaperone Hsp104 (heat shock protein 104). Although these observations provide a strong genetic argument in support of the “protein-only” or “prion” hypothesis for [PSI+], there is, as yet, no direct evidence of an interaction between the two proteins. We report that when purified Sup35 and Hsp104 are mixed, the circular dichroism (CD) spectrum differs from that predicted by the addition of the proteins’ individual spectra, and the ATPase activity of Hsp104 is inhibited. Similar results are obtained with two other amyloidogenic substrates, mammalian PrP and β-amyloid 1-42 peptide, but not with several control proteins. With a group of peptides that span the PrP protein sequence, those that produced the largest changes in CD spectra also caused the strongest inhibition of ATPase activity in Hsp104. Our observations suggest that (i) previously described genetic interactions between Hsp104 and [PSI+] are caused by direct interaction between Hsp104 and Sup35; (ii) Sup35 and PrP, the determinants of the yeast and mammalian prions, respectively, share structural features that lead to a specific interaction with Hsp104; and (iii) these interactions couple a change in structure to the ATPase activity of Hsp104.