Interaction between calpain-1 and HSP90: new insights into the regulation of localization and activity of the protease.
Interaction between calpain-1 and HSP90: new insights into the regulation of localization and activity of the protease.
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DOI：
10.1371/journal.pone.0116738
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Melloni E
中科院分区：
文献类型：
--
作者：
Averna M;De Tullio R;Pedrazzi M;Bavestrello M;Pellegrini M;Salamino F;Pontremoli S;Melloni E
在这里，我们表明，热休克蛋白90（HSP 90）与钙蛋白酶-1，但不与钙蛋白酶-2相互作用，并形成一个离散的复合物中的蛋白酶保持其催化活性，但与较低的亲和力Ca 2+。平衡凝胶分布实验表明，这种复合物是由每个蛋白质伴侣的相等数量的分子组成的。此外，在静息细胞中，胞浆钙蛋白酶-1与HSP 90完全相关。由于钙蛋白酶-1与HSP 90结合，保留了其蛋白水解活性，并且在没有Ca 2+的情况下，伴侣蛋白也被钙蛋白酶抑制素取代，因此蛋白酶的催化裂缝不参与这种结合。因此，钙蛋白酶-1可以形成两个不同的复合物，这取决于钙蛋白酶抑制素在胞质溶胶中的可用性。HSP 90和钙蛋白酶-1之间的复合物的出现，其中蛋白酶仍然是可激活的，可以防止蛋白酶的完全抑制，即使在高钙蛋白酶抑制素水平的存在下。我们还表明，在基底细胞条件下，热休克蛋白90和钙蛋白酶-1，但不是钙蛋白酶-2，插入在多蛋白N-甲基-D-天冬氨酸受体（NMDAR）复合物。在NMDAR簇中的钙蛋白酶-1的量在[Ca 2 +]i增加的条件下不改变，并且这种常驻蛋白酶参与NMDAR组分的加工。最后，与NMDAR簇相关的钙蛋白酶-1的量与Ca 2+介导的易位无关。我们的研究结果表明，热休克蛋白90起着重要的作用，在维持一个给定的和适当的量的钙蛋白酶-1的功能位点。
Here we demonstrate that heat shock protein 90 (HSP90) interacts with calpain-1, but not with calpain-2, and forms a discrete complex in which the protease maintains its catalytic activity, although with a lower affinity for Ca2+. Equilibrium gel distribution experiments show that this complex is composed by an equal number of molecules of each protein partner. Moreover, in resting cells, cytosolic calpain-1 is completely associated with HSP90. Since calpain-1, in association with HSP90, retains its proteolytic activity, and the chaperone is displaced by calpastatin also in the absence of Ca2+, the catalytic cleft of the protease is not involved in this association. Thus, calpain-1 can form two distinct complexes depending on the availability of calpastatin in the cytosol. The occurrence of a complex between HSP90 and calpain-1, in which the protease is still activable, can prevent the complete inhibition of the protease even in the presence of high calpastatin levels. We also demonstrate that in basal cell conditions HSP90 and calpain-1, but not calpain-2, are inserted in the multi-protein N-Methyl-D-Aspartate receptor (NMDAR) complex. The amount of calpain-1 at the NMDAR cluster is not modified in conditions of increased [Ca2+]i, and this resident protease is involved in the processing of NMDAR components. Finally, the amount of calpain-1 associated with NMDAR cluster is independent from Ca2+-mediated translocation. Our findings show that HSP90 plays an important role in maintaining a given and proper amount of calpain-1 at the functional sites.