The contractile ring is a complex molecular apparatus important for dividing many eukaryotic cells. Despite knowledge of its composition, the molecular architecture of the ring is not known. Here we applied super-resolution microscopy and FRET to determine the nanoscale spatial organization of Schizosaccharomyces pombe contractile ring components relative to the plasma membrane. As in other membrane-tethered actin structures, contractile ring proteins are stratified relative to the membrane. The lowest layer (0-80 nm) contains membrane-binding scaffolds, formin, and the myosin-II tail. An intermediate zone (80-160 nm) consists of a network of cytokinesis accessory proteins and signaling components that influence cell division. Most interior from the membrane (160-400 nm) is F-actin, myosin motor domains, and an F-actin crosslinker. Circumferentially within the ring, multiple proximal membrane proteins form different sized clusters, while components farther from the membrane are uniformly distributed. This comprehensive organizational map provides a framework for understanding contractile ring function.

收缩环是一种复杂的分子装置，对于分裂许多真核细胞很重要。尽管知道其组成，环的分子结构仍是未知的。在这里，我们应用超分辨率显微镜和FRET来确定粟酒裂殖酵母的纳米级空间组织相对于质膜的收缩环成分。与其他膜系肌动蛋白结构一样，收缩环蛋白相对于膜是分层的。最下层（0-80 nm）包含膜结合支架，甲酰胺和肌球蛋白II尾部。中间区域（80-160 nm）由胞质分裂辅助蛋白和影响细胞分裂的信号传导成分网络组成。膜的大部分内部区域（160-400 nm）是F-肌动蛋白，肌球蛋白运动域和F-肌动蛋白交联剂。在环的周围，多个近端膜蛋白形成不同大小的簇，而远离膜的成分则均匀分布。这种全面的组织结构图提供了一个了解收缩环功能的框架。