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Michael A. Glotzer, PhD

The Glotzer lab focuses on questions related to cell organization. How do cells coordinate the position of the contractile ring with the position of the spindle? By what mechanisms are cortical domains that mediate cell polarization assembled and maintained? How do cells regulate cortical contractility during developmental morphogenesis?



To answer these questions, we use the nematode C. elegans, cultured human cells, budding yeast, and Drosophila as model systems and we combine forward and reverse genetics, biochemistry, and live cell imaging. Through these approaches we have discovered and extensively characterized the centralspindlin complex, a multifunctional protein complex that regulates essentially every step of cytokinesis.



Not only are centralspindlin and Ect2 implicated in cell division, they are also implicated in the evolution of animals. Phylogenomic and structural analysis indicates that the last common ancestor of animals had the centralspindlin complex and Ect2 and the motifs that mediate inter-subunit interactions - they appear evolutionarily fixed. Some species of Choanoflagellate - the closest taxonomic neighbors of animals - have proteins related to centralspindlin and Ect2 but the interfaces that mediate their interactions are not well conserved. Metazoan germlines are organized in cysts, that form via incomplete cytokinesis. We propose that the evolutionary refinement of centralspindlin enabled the formation of such cysts and the ability of spindle positioning to direct cell division.



We have pioneered the use of optogenetics to dissect spatiotemporally regulated processes. Using these approaches, we have demonstrated that RhoA activation is sufficient to induce cleavage furrows irrespective of the position of the spindle or the stage of the cell cycle. Likewise, we obtained direct evidence that positive feedback is active during yeast cell polarization. By combining optogenetics with "conventional" genetics and live cell imaging we can directly test models for how cells endow well defined cortical regions with distinct properties that are required for complex cellular events, like cell division, cell polarization, and tissue scale morphogenetic events, such as gastrulation.