Molybdate inhibits hsp90, induces structural changes in its C-terminal domain, and alters its interactions with substrates
Molybdate inhibits hsp90, induces structural changes in its C-terminal domain, and alters its interactions with substrates
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DOI：
10.1021/bi983027s
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发表时间：
1999-03-23
期刊：
影响因子：
2.9
通讯作者：
Matts, RL
中科院分区：
文献类型：
--
作者：
Hartson, SD;Thulasiraman, V;Matts, RL
为了研究热休克蛋白90对某些信号转导蛋白发挥重要正向作用的生化机制，我们研究了钼酸盐和格尔达霉素对热休克蛋白90功能和结构的影响。钼酸盐抑制HSP90介导的p56(Lck)的生物合成和荧光素酶的复性，同时加强与这些底物的盐稳定性相互作用。钼酸盐还减少了细胞裂解产物中的游离热休克蛋白90的含量，抑制了热休克蛋白90的S与格尔达霉素的结合能力，并在热休克蛋白90的C-末端结构域的特定区域诱导了对蛋白降解的抵抗。相反，HSP90抑制剂格尔达那霉素阻止HSP90呈现自然或钼酸盐诱导的构象，这些构象允许盐稳定地与底物相互作用。当这些化合物连续应用时，添加的顺序决定了观察到的效果，表明这些试剂对HSP90具有相反的作用。我们的结论是，HSP90 C-末端结构域(接近残基600)中的一个特定区域决定了HSP90与底物相互作用的方式，并且HSP90在不同相互作用模式之间循环的能力是HSP90功能所必需的。
To examine the biochemical mechanism by which hsp90 exerts its essential positive function on certain signal transduction proteins, we characterized the effects of molybdate and geldanamycin on hsp90 function and structure. Molybdate inhibited hsp90-mediated p56(lck) biogenesis and luciferase renaturation while enforcing salt-stable interactions with these substrates. Molybdate also reduced the amount of free hsp90 present in cell lysates, inhibited hsp90's ability to bind geldanamycin, and induced resistance to proteolysis at a specific region within the C-terminal domain of hsp90. In contrast, the hsp90 inhibitor geldanamycin prevented hsp90 from assuming natural or molybdate-induced conformations that allow salt-stable interactions with substrates. When these compounds were applied sequentially, the order of addition determined the effects observed, indicating that these agents had opposing effects on hsp90. We conclude that a specific region within the C-terminal domain of hsp90 (near residue 600) determines the mode by which hsp90 interacts with substrates and that the ability of hsp90 to cycle between alternative modes of interaction is obligatory for hsp90 function.