Haslbeck M
Institut für Organische Chemie und Biochemie, Technische Universität München, 85747 Garching, Germany.
Cell Mol Life Sci. 2002 Oct;59(10):1649-57. doi: 10.1007/pl00012492.
Small Hsps (sHsps) encompass a widespread but diverse class of proteins. These low molecular mass proteins (15-42 kDa) form dynamic oligomeric structures ranging from 9 to 50 subunits. sHsps display chaperone function in vitro, and in addition they have been suggested to be involved in the inhibition of apoptosis, organisation of the cytoskeleton and establishing the refractive properties of the eye lens in the case of a-crystallin. How these different functions can be explained by a common mechanism is unclear at present. However, as most of the observed phenomena involve nonnative protein, the repeatedly reported chaperone properties of sHsps seem to be of key importance for understanding their function. In contrast to other chaperone families, sHsps bind several nonnative proteins per oligomeric complex, thus representing the most efficient chaperone family in terms of the quantity of substrate binding. In some cases, the release of substrate proteins from the sHsp complex is achieved in cooperation with Hsp70 in an ATP-dependent reaction, suggesting that the role of sHsps in the network of chaperones is to create a reservoir of nonnative refoldable protein.
小分子热休克蛋白（sHsps）是一类广泛存在但种类多样的蛋白质。这些低分子量蛋白质（15 - 42 kDa）形成由9到50个亚基组成的动态寡聚结构。sHsps在体外表现出伴侣功能，此外，有人认为它们参与抑制细胞凋亡、细胞骨架的组织以及在α - 晶体蛋白的情况下建立晶状体的屈光特性。目前尚不清楚如何用一种共同机制来解释这些不同的功能。然而，由于观察到的大多数现象都涉及非天然蛋白质，sHsps反复被报道的伴侣特性似乎对于理解其功能至关重要。与其他伴侣蛋白家族不同，sHsps每个寡聚复合体结合几种非天然蛋白质，因此就底物结合量而言，代表了最有效的伴侣蛋白家族。在某些情况下，底物蛋白从sHsp复合体中的释放是在ATP依赖反应中与Hsp70协同完成的，这表明sHsps在伴侣蛋白网络中的作用是创建一个非天然可重折叠蛋白质的储备库。
