Too much of a good thing: regulatory and structural brakes underlie contractile oscillations in cytokinesis

Dr Amy Shaub Maddox from the University of North Carolina (USA) leads a small but diverse team of researchers to understand the molecular mechanisms of cell shape stability and dynamics. Cytokinesis, the physical division of one cell into two, is driven by a highly dynamic ring of cellular polymers, motors and crosslinkers (collectively called the cortical cytoskeleton). These same cellular machines are also enriched on the stable rings that maintain structure and communication in syncytia, which are massive cells containing multiple nuclei. Many cells do cytokinesis, when they make a copy of themselves. Syncytia are common throughout nature, especially in the tissues that generate sperm and egg cells. How the cortical cytoskeleton remodels to define cell shape is poorly understood. The Maddox lab uses cell and developmental biology, genetics, biochemistry, computer-aided image processing, advanced statistics, and computational modeling to study cytokinesis and syncytia. Their work on dynamic and stable actomyosin structures converged on a focus on regulatory and structural brakes that limit contractility. Coincidentally, by examining cytokinesis with unprecedented temporal resolution, the Maddox lab observed oscillations in ring closure, so they are now working to define the regulatory and structural bases for time-delayed negative feedback underlying contractility in the ring. The team also places significant emphasis on outreach to a variety of audiences throughout the course of their research. They host undergraduate research interns and primary school teachers in the lab, and devise imaginative techniques to stimulate interdisciplinary interactions. They hold scientific speed-dating events for biologists to meet computational scientists, and coordinate the lunchMatrix, a department-wide program for randomized casual interactions.