Hsp90 is an abundant and special molecular chaperone considered to be the regulator of many transcription factors and signaling kinases. Its high abundance is indicative of its involvement in some more fundamental processes. In this study, we provide evidence that Hsp90 is required for microtubule stabilization, Golgi organization and vesicular trafficking. We showed that Hsp90 is bound to microtubule-associated protein MAP 4, which is essential for maintaining microtubule acetylation and stabilization. Hsp90 depletion led to the decrease of MAP 4, causing microtubule deacetylation and destabilization. Furthermore, in Hsp90-depleted cells Golgi was fragmented and anterograde vesicle trafficking was impaired, phenotypes similar to those induced by silencing MAP 4. These disruptive effects of Hsp90 depletion could be rescued by the expression of exogenous MAP 4 or the treatment of trichostatin A that increases microtubule acetylation as well as stability. Thus, microtubule stability is an essential cellular event regulated by Hsp90.

中文翻译：

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分子伴侣 Hsp90 通过调节微管稳定性维持高尔基体组织和囊泡运输。

Hsp90 是一种丰富且特殊的分子伴侣，被认为是许多转录因子和信号激酶的调节剂。它的高丰度表明它参与了一些更基本的过程。在这项研究中，我们提供证据表明 Hsp90 是微管稳定、高尔基体组织和囊泡运输所必需的。我们发现 Hsp90 与微管相关蛋白 MAP 4 结合，这对于维持微管乙酰化和稳定至关重要。Hsp90 耗竭导致 MAP 4 减少，导致微管脱乙酰化和不稳定。此外，在 Hsp90 耗尽的细胞中，高尔基体破碎，顺行囊泡运输受损，表型与沉默 MAP 4 诱导的表型相似。Hsp90 耗竭的这些破坏性影响可以通过外源性 MAP 4 的表达或增加微管乙酰化和稳定性的曲古抑菌素 A 的处理来挽救。因此，微管稳定性是由 Hsp90 调节的重要细胞事件。