Cryo-EM study of patched in lipid nanodisc suggests a structural basis for its clustering in caveolae.
Cryo-EM study of patched in lipid nanodisc suggests a structural basis for its clustering in caveolae.
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DOI：
10.2139/ssrn.3780328
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发表时间：
2021-02
期刊：
影响因子：
5.7
通讯作者：
Yitian Luo;G. Wan;Xiang Zhang;Xuan Zhou;Qiuwen Wang;Jialin Fan;H. Cai;Liya Ma;Hailong Wu;Q. Qu;Y. Cong;Yun Zhao;Dianfan Li
中科院分区：
文献类型：
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作者：
Yitian Luo;G. Wan;Xiang Zhang;Xuan Zhou;Qiuwen Wang;Jialin Fan;H. Cai;Liya Ma;Hailong Wu;Q. Qu;Y. Cong;Yun Zhao;Dianfan Li
12-跨膜蛋白补丁（Ptc1）作为Hedgehog （Hh）信号的抑制因子，通过消耗细胞质膜小叶中的甾醇来激活下游调节因子。正调节因子Hh通过与Ptc1及其共受体结合抑制Ptc1的转运蛋白功能，Ptc1及其共受体局部集中在内陷的微域，称为小泡。在这里，我们将小鼠Ptc1重组成脂质纳米片，并使用单粒子冷冻电子显微镜确定其结构。其结构总体上与双酚类和洗涤剂中的结构相似，但在跨膜区域表现出不同的构象差异。虽然大多数粒子显示为单体，但我们观察到Ptc1二聚体具有不同的相互作用模式和不同的膜曲率，其中一些使人想起小泡。我们发现一个富含疏水和芳香残基的膜外“握手”区域在不同的膜曲率下介导ptc1之间的相互作用。我们的数据为Ptc1在高度弯曲的小泡中的聚类提供了一个合理的框架。
The 12-transmembrane protein Patched (Ptc1) acts as a suppressor for Hedgehog (Hh) signaling by depleting sterols in the cytoplasmic membrane leaflet that are required for the activation of downstream regulators. The positive modulator Hh inhibits Ptc1's transporter function by binding to Ptc1 and its co-receptors, which are locally concentrated in invaginated microdomains known as caveolae. Here, we reconstitute the mouse Ptc1 into lipid nanodiscs and determine its structure using single-particle cryoelectron microscopy. The structure is overall similar to those in amphipol and detergents but displays various conformational differences in the transmembrane region. Although most particles show monomers, we observe Ptc1 dimers with distinct interaction patterns and different membrane curvatures, some of which are reminiscent of caveolae. We find that an extramembranous "hand-shake" region rich in hydrophobic and aromatic residues mediates inter-Ptc1 interactions under different membrane curvatures. Our data provide a plausible framework for Ptc1 clustering in the highly curved caveolae.