Heat shock protein (Hsp) 70 is an activator of the Hsp104 motor
Heat shock protein (Hsp) 70 is an activator of the Hsp104 motor
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DOI：
10.1073/pnas.1217988110
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发表时间：
2013-05-21
影响因子：
11.1
通讯作者：
Tsai, Francis T. F.
中科院分区：
文献类型：
--
作者：
Lee, Jungsoon;Kim, Ji-Hyun;Tsai, Francis T. F.
热休克蛋白（Hsp） 104是一种环状形成的蛋白质重塑机器，它利用ATP结合和水解的能量来驱动蛋白质分解。虽然Hsp104是一种活性atp酶，但功能蛋白的恢复需要Hsp70系统的物种特异性合作。然而，与Hsp104一样，Hsp70也是一种活性atp酶，它可以识别聚集蛋白和易聚集蛋白，因此很难区分Hsp104和Hsp70在蛋白质分解过程中的机制作用。利用肽阵列技术和光交联技术绘制酵母Hsp104的hsp70结合位点，发现尽管缺乏序列同一性，但Hsp104中间区域的主要hsp70结合基序在不同物种间具有惊人的保守性。值得注意的是，在空间保守的hsp70结合位点插入一个strep - tack结合基序，可以引发Hsp104蛋白分解活性，该活性现在依赖于strep - tack而不再需要Hsp70/40。与strep - tactin依赖性激活步骤一致，我们发现全长Hsp70本身可以通过促进亚基间协调来激活Hsp104六聚体，这表明Hsp70是Hsp104马达的激活剂。
Heat shock protein (Hsp) 104 is a ring-forming, protein-remodeling machine that harnesses the energy of ATP binding and hydrolysis to drive protein disaggregation. Although Hsp104 is an active ATPase, the recovery of functional protein requires the species-specific cooperation of the Hsp70 system. However, like Hsp104, Hsp70 is an active ATPase, which recognizes aggregated and aggregation-prone proteins, making it difficult to differentiate the mechanistic roles of Hsp104 and Hsp70 during protein disaggregation. Mapping the Hsp70-binding sites in yeast Hsp104 using peptide array technology and photo-cross-linking revealed a striking conservation of the primary Hsp70-binding motifs on the Hsp104 middle-domain across species, despite lack of sequence identity. Remarkably, inserting a Strep-Tactin binding motif at the spatially conserved Hsp70-binding site elicits the Hsp104 protein disaggregating activity that now depends on Strep-Tactin but no longer requires Hsp70/40. Consistent with a Strep-Tactin-dependent activation step, we found that full-length Hsp70 on its own could activate the Hsp104 hexamer by promoting intersubunit coordination, suggesting that Hsp70 is an activator of the Hsp104 motor.