Structural basis of p62/SQSTM1 helical filaments and their role in cellular cargo uptake
Structural basis of p62/SQSTM1 helical filaments and their role in cellular cargo uptake
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DOI：
10.1038/s41467-020-14343-8
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发表时间：
2020-01-23
影响因子：
16.6
通讯作者：
Sachse, Carsten
中科院分区：
文献类型：
--
作者：
Jakobi, Arjen J.;Huber, Stefan T.;Sachse, Carsten
p62/SQSTM1 是一种自噬受体和信号转导接头，具有 N 端 PB1 结构域，可形成细胞中相分离的 p62 体的支架。体外控制 PB1 结构域丝形成的分子决定因素仍有待确定，p62 丝在细胞内的作用目前尚不清楚。我们在这里确定了不同人类和拟南芥 PB1 结构域组件的四种高分辨率冷冻电镜结构，并使用相关细胞电镜观察了 p62/SQSTM1 体的丝状超微结构。我们表明，由 PB1 结构域中的双精氨酸指驱动的寡聚或聚合是溶酶体靶向 p62 的一般要求。此外，p62 的丝状组装状态是 p62 特异性货物 KEAP1 的自噬体加工所必需的。我们的结果表明，利用这种机制，p62 丝对于自噬中的货物摄取至关重要，并且是相分离 p62 体的组成部分。 PB1 介导的 p62/SQSTM1 寡聚对其作为选择性自噬受体的功能至关重要。在此，作者展示了人类和拟南芥 PB1 结构域螺旋组装体的冷冻电镜结构，并发现 PB1 结构域中保守的双精氨酸指对于 p62 聚合和 p62 的溶酶体靶向非常重要。
p62/SQSTM1 is an autophagy receptor and signaling adaptor with an N-terminal PB1 domain that forms the scaffold of phase-separated p62 bodies in the cell. The molecular determinants that govern PB1 domain filament formation in vitro remain to be determined and the role of p62 filaments inside the cell is currently unclear. We here determine four high-resolution cryo-EM structures of different human and Arabidopsis PB1 domain assemblies and observed a filamentous ultrastructure of p62/SQSTM1 bodies using correlative cellular EM. We show that oligomerization or polymerization, driven by a double arginine finger in the PB1 domain, is a general requirement for lysosomal targeting of p62. Furthermore, the filamentous assembly state of p62 is required for autophagosomal processing of the p62-specific cargo KEAP1. Our results show that using such mechanisms, p62 filaments can be critical for cargo uptake in autophagy and are an integral part of phase-separated p62 bodies. PB1-mediated oligomerization of p62/SQSTM1 is essential for its function as a selective autophagy receptor. Here the authors present the cryo-EM structures of human and Arabidopsis PB1 domain helical assemblies and find that a conserved double arginine finger in the PB1 domain is important for p62 polymerisation and lysosomal targeting of p62.