Max-Delbrück-Centrum für Molekulare Medizin, 13125 Berlin, Germany; Institut für Chemie und Biochemie, Freie Universität Berlin, 14195 Berlin, Germany.
Charité Universitätsmedizin Berlin, 10117 Berlin, Germany.
Structure. 2019 Dec 3;27(12):1830-1841.e3. doi: 10.1016/j.str.2019.10.001. Epub 2019 Oct 21.
The hexameric ring structure of the type II AAA+ ATPases is considered as stable and permanent. Recently, the UBX domain-containing cofactors Arabidopsis thaliana PUX1 and human alveolar soft part sarcoma locus (ASPL) were reported to bind and disassemble the cognate AAA+ ATPases AtCDC48 and human p97. Here, we present two crystal structures related to these complexes: a truncated AtCDC48 (AtCDC48-ND1) and a hybrid complex containing human p97-ND1 and the UBX domain of plant PUX1 (p97-ND1:PUX1-UBX). These structures reveal close similarity between the human and plant AAA+ ATPases, but also highlight differences between disassembling and non-disassembling AAA+ ATPase cofactors. Based on an AtCDC48 disassembly assay with PUX1 and known crystal structures of the p97-bound human cofactor ASPL, we propose a general ATPase disassembly model. Thus, our structural and biophysical investigations provide detailed insight into the mechanism of AAA+ ATPase disassembly by UBX domain cofactors and suggest a general mode of regulating the cellular activity of these molecular machines.
六聚体环结构的 II 型 AAA+ATP 酶被认为是稳定和永久的。最近，含有 UBX 结构域的植物拟南芥 PUX1 和人类肺泡软组织肉瘤基因（ASPL）的辅因子被报道与相应的 AAA+ATP 酶 AtCDC48 和人类 p97 结合并使其解体。在这里，我们呈现了两个与这些复合物相关的晶体结构：一个截断的 AtCDC48（AtCDC48-ND1）和一个包含人类 p97-ND1 和植物 PUX1 的 UBX 结构域的杂种复合物（p97-ND1:PUX1-UBX）。这些结构揭示了人类和植物 AAA+ATP 酶之间的紧密相似性，但也突出了解体和非解体 AAA+ATP 酶辅因子之间的差异。基于 AtCDC48 与 PUX1 的解组装测定以及已知的 p97 结合的人类辅因子 ASPL 的晶体结构，我们提出了一个通用的 ATP 酶解组装模型。因此，我们的结构和生物物理研究为 UBX 结构域辅因子介导的 AAA+ATP 酶解组装机制提供了详细的见解，并提出了调节这些分子机器细胞活性的一般模式。
