Multiscale imaging of cytokinesis
After separation of duplicated genetic material, animal cells divide by cytokinesis. This process involves several simultaneous and successive steps of molecular reorganization at cell membrane, cortex and the spindle apparatus as the cleavage furrow ingresses and the spindle is transformed into the intercellular bridge. Dozens of proteins play a role in cytokinesis. However, a comprehensive view of their successive nanoscale reorganizations over cytokinesis remains untractable with current microscopy methods. Here, we developed a multimodal imaging and analysis framework to investigate the relative organization of key cytokinetic molecules over time. We extract cytokinetic hallmarks from live-cell lattice light-sheet and expansion microscopy (ExM) to computationally define pseudotime and align nanoscale ExM images of cytokinesis. We discover a cytokinetic substep and create nanoscale maps of the intercellular bridge and the midbody in 6 stages for 20 involved molecules. We thus provide a framework for nanoscale analysis of cytokinesis, a process fundamental to life.