Requirement of Hsp90 activity for IκB kinase (IKK) biosynthesis and for constitutive and inducible IKK and NF-κB activation
Requirement of Hsp90 activity for IκB kinase (IKK) biosynthesis and for constitutive and inducible IKK and NF-κB activation
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DOI：
10.1038/sj.onc.1207705
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发表时间：
2004-07-08
期刊：
影响因子：
8
通讯作者：
Scheidereit, C
中科院分区：
文献类型：
--
作者：
Broemer, M;Krappmann, D;Scheidereit, C
分子伴侣Hsp 90影响许多信号分子的功能和命运。我们研究了热休克蛋白90对IkappaB激酶（IKK）复合物和NF-κ B组成型和诱导型活性的要求。Hsp 90 ATP酶抑制剂格尔德霉素（GA）和根赤霉素（RC）的抑制作用表明，Hsp 90在两个水平上控制IKK，诱导酶活性和生物合成，这可以分别通过短时间和长时间GA孵育来区分。TNF α、IL-1 β或佛波酯PMA短时间抑制Hsp 90导致IKK激酶活化受损。此外，GA抑制霍奇金淋巴瘤细胞中IKK和NF-κ B的组成性激活。热休克蛋白90的功能也需要转染IKK β的反式和自身磷酸化。GA暴露数小时导致IKK复合体α、β和γ亚基不同程度的下调。蛋白酶体抑制干扰GA介导的IKK耗竭，Hsp 90抑制诱导蛋白合成过程中IKK α和β的多聚泛素化。事实上，GA阻断IKK α和IKK β的生物合成，但不干扰翻译后周转。总之，这些结果定义了Hsp 90作为NF-κ B信号转导调节剂的双重要求，即其一般参与IKK激活和IKK稳态的作用。
The molecular chaperone Hsp90 affects the function and fate of a number of signaling molecules. We have investigated the Hsp90 requirement for constitutive and inducible activity of the IkappaB kinase (IKK) complex and of NF-kappaB. Inhibition by the Hsp90 ATPase inhibitors, geldanamycin (GA) and radicicol ( RC), revealed that Hsp90 controls IKKs at two levels, inducibility of enzymatic activity and biogenesis, which can be discriminated by short- and long-time GA incubation, respectively. Short-time inhibition of Hsp90 resulted in impaired IKK kinase activation by TNFalpha, IL-1beta or phorbolester PMA. Furthermore, GA inhibited constitutive activation of IKK and NF-kappaB in Hodgkin's lymphoma cells. Hsp90 function was also required for trans- and autophosphorylation of transfected IKKbeta. GA exposure for several hours resulted in a downmodulation of IKK complex alpha, beta and gamma subunits to various extent. Proteasome inhibition interfered with GA mediated IKK depletion and Hsp90 inhibition induced polyubiquitination of IKKalpha and beta during protein synthesis. In fact, GA blocked biogenesis of IKKalpha and IKKbeta but did not interfere with post-translational turnover. Together, these results define a dual requirement for Hsp90 as a regulator of NF-kappaB signaling by its general involvement in IKK activation and by its role in IKK homeostasis.