The sorting nexin (SNX) family of proteins deform the membrane to generate transport carriers in endosomal pathways. Here, we elucidate how a prototypic member, SNX1, acts in this process. Performing cryoelectron microscopy, we find that SNX1 assembles into a protein lattice that consists of helical rows of SNX1 dimers wrapped around tubular membranes in a crosslinked fashion. We also visualize the details of this structure, which provides a molecular understanding of how various parts of SNX1 contribute to its ability to deform the membrane. Moreover, we have compared the SNX1 structure with a previously elucidated structure of an endosomal coat complex formed by retromer coupled to a SNX, which reveals how the molecular organization of the SNX in this coat complex is affected by retromer. The comparison also suggests insight into intermediary stages of assembly that results in the formation of the retromer-SNX coat complex on the membrane.

分选连接蛋白 (SNX) 蛋白家族使膜变形以在内体途径中产生转运载体。在这里，我们阐明了原型成员 SNX1 在此过程中的作用。进行冷冻电子显微镜检查，我们发现 SNX1 组装成一个蛋白质晶格，该晶格由以交联方式缠绕在管状膜上的 SNX1 二聚体螺旋行组成。我们还将这种结构的细节可视化，这提供了对 SNX1 的各个部分如何促成其使膜变形的能力的分子理解。此外，我们将 SNX1 结构与先前阐明的由逆向异构体与 SNX 偶联形成的内体外壳复合物的结构进行了比较，这揭示了逆向异构体如何影响该外壳复合物中 SNX 的分子组织。