Actomyosin Network in Mechanosensation and Cytokinesis: a Novel Workflow for Animating Cell Division

A cell’s survival in large part depends on its ability to respond to cues from its environment. Cellular response to chemical cues in the form of hormones, neurotransmitters and even invading viruses is given a great deal of attention in high school Advanced Placement and college freshman Biology coursework. However, a cell’s ability to respond to mechanical cues by reconstructing its intricate cytoskeleton is not addressed, despite the crucial role mechanosensing plays in cell biology and in human physiology. Work in the Robinson Lab at Johns Hopkins University provides great insights into the processes of cell motility and cell division. Their studies of mechanosensing behavior, beginning with a model organism, Dictyostelium, elucidate aspects of human tissue homeostasis that underlie development of cancer and could explain the prognostic disparity among patients. This field of research involves integration of several highly formal, specialized subfields of fluid physics, computational modeling, protein dynamics, genetics and molecular biology. Our challenge was to communicate the research concepts of Robinson’s lab to a lay audience unfamiliar with the phenomenon of mechanosensing. A novel workflow was developed to streamline parsing of such complex information into a creative collaboration between researcher and artist. Appropriate level of detail for the audience was determined, and a linear narrative form was identified as the optimal way to introduce an unfamiliar topic. A four minute and 45 second overview animatic was created. In it we introduced the key proteins involved in mechanosensitive meshwork of a cell, utilizing analogy as a primary means of relaying concepts of scale, feedback and cooperative binding as well as providing some entertainment value to keep the audience’s attention. We then focused on a protein Myosin II, delineating its component domains; describing its assembly into its functional unit, the bipolar thick filament (BTF); and showing its motor domain activity - first on unrestrained Actin filaments, and secondly on actin filaments anchored by Cortexillin (Robinson, 2012). We then explained the Myosin-Actin-Cortexilin system’s role in a feedback loop promoting BTF assembly, and finally provided a view of Myosin II function in creating the cleavage furrow during cytokinesis. A 3D model of a dividing cell was created in MAXON Cinema4D, set up to feed research data for protein concentration changes into a custom XPresso setup. A system of particles was generated with the X-Particles plugin and set up to receive the data from XPresso. An action plan was developed for further improvement and integration of the model into an interactive user interface