Franzmann Titus M, Menhorn Petra, Walter Stefan, Buchner Johannes
Department Chemie, Center for Integrative Protein Science Munich, Technische Universität München, Garching, Germany.
Mol Cell. 2008 Feb 1;29(2):207-16. doi: 10.1016/j.molcel.2007.11.025.
Cells respond to a sudden increase in temperature with the transcription of a special set of genes, a phenomenon known as the heat shock response. In the yeast S. cerevisiae, the molecular chaperone Hsp26 is one component of the heat shock response. Hsp26 has the remarkable ability to sense increases in temperature directly and can switch from an inactive to a chaperone-active state. The underlying principle of this temperature regulation has remained enigmatic. Hsp26 variants with altered spectroscopic properties allowed us to identify structural elements controlling this activation process. We show that temperature sensing by Hsp26 is a feature of its middle domain that changes its conformation within a narrow temperature range. This structural rearrangement allows Hsp26 to respond autonomously and directly to heat stress by reversibly unleashing its chaperone activity. Thus, the Hsp26 middle domain is a thermosensor and intrinsic regulator of chaperone activity.
细胞会通过转录一组特殊的基因来应对温度的突然升高，这一现象被称为热休克反应。在酿酒酵母中，分子伴侣Hsp26是热休克反应的一个组成部分。Hsp26具有直接感知温度升高的非凡能力，并且能够从无活性状态转变为具有伴侣活性的状态。这种温度调节的潜在机制一直是个谜。具有改变的光谱特性的Hsp26变体使我们能够识别控制这一激活过程的结构元件。我们表明，Hsp26的温度感应是其中间结构域的一个特性，该结构域在狭窄的温度范围内会改变其构象。这种结构重排使Hsp26能够通过可逆地释放其伴侣活性来自主且直接地应对热应激。因此，Hsp26中间结构域是一种热传感器和伴侣活性的内在调节器。
