Deep Insight Section

During cell division the genome is duplicated and segregated along with organelles into the daughter cells with high fidelity. The physical separation of the two daughter cells topologically resembles virus budding and multivesicular endosome (MVE) formation in the sense that they all involve outward budding from cytosol. According to the crucial role of the Endosomal Sorting Complex Required for Transport (ESCRT) machinery that pinches off membranes in MVE biogenesis and virus budding, extensive work from several laboratories during the last six years has now confirmed an essential role of ESCRT members also in cytokinesis. This Deep Insight highlights the current views explaining how the ESCRT machinery and associated proteins collaborate to drive abscission of the intercellular bridge at the correct time when DNA and organelles are successfully segregated. Even though the ESCRT machinery seems to play a central role for proper cytokinesis, it is important to emphasize that alternative mechanisms for abscission have been proposed. Before the role of ESCRTs in cell division was discovered, secretory vesicles and recycling endosomes were hypothesized to provide the molecular machinery required for abscission (Neto et al., 2011). However, this hypothesis is lately debated based on electron microscopy studies showing busy vesicle trafficking in the intercellular bridge early in cytokinesis but not when abscission occurs. Rather these vesicles seem to play important roles prior to abscission, in the thinning of the intercellular bridge, which will be described later.