During cytokinesis, a filamentous protein ring contracts around the cell equator to form a cleavage furrow. Before abscission, the two daughter cells are connected by a midbody, which is either engulfed or released as a midbody remnant. In this study, Joshua Bembenek and colleagues employ C. elegans embryos to study cytokinesis during development, by live imaging of cytokinesis components such as the Aurora B kinase (AIR-2), which marks the midbody. Importantly, the authors observe reproducible modified processes of cytokinesis for polarised tissues. In the intestine and pharynx, the midbody migrates to the nascent apical midline and AIR-2 remains at the apical surface even after abscission. Using heat inactivation or tissue-specific degradation of AIR-2 in the gut, the authors show that the kinase is required for organisation of the apical surface in intestinal cells. Similarly, in sensilla neurons, the midbodies of several dividing cells migrate to the apical surface, forming a rosette. Degradation of AIR-2 in sensory neurons results in a wider distribution of cell bodies, indicating a function for apical polarised AIR-2 in neuronal morphogenesis. Although the mechanism remains to be elucidated, these data reveal a specialised form of cytokinesis for polarisation dependent on a new role for AIR-2.
