**5. Conclusions and future objectives**

Work from multiple laboratories in the last few years has significantly advanced our understanding about the core machinery of the abscission step of cytokinesis. All these data have demonstrated that cell abscission is an immensely complicated event that involves coordinated changes in membrane transport, microtubules, the actin cytoskeleton, septin filaments and the ESCRT complexes. How all these components are regulated, and what the mechanisms of the cross-talk between them may be, remain completely unknown and will be the focus of future studies. One of the biggest problems in studying the spatiotemporal dynamics of various cellular components during cell division has been the inability to visualize the individual organelles or cytoskeletal elements within the intracellular bridge, due to the resolution limits of the light microscopy. The emergence of novel superresolution imaging techniques, such as photo-activated localization microscopy (PALM), stimulated emission depletion microscopy (STED) and correlation high-resolution tomography will allow us to begin addressing some of these questions and testing/combining multiple competing abscission models.

#### **6. Acknowledgments**

I am grateful to John Schiel (UC SOM) and Carly Willenborg (UC SOM) for a critical reading of the manuscript. I apologize to all colleagues for not being able to cite all work related to cytokinesis, due to the focused nature of this review. Work in the Prekeris laboratory has been funded by the National Institute of Health (DK064380), Susan G. Komens Breast Cancer Research Foundation and the Cancer League of Colorado Foundation.
