In this CAREER proposal the PI proposes to study a fundamental question in biology: How do nanometer-scale proteins give rise to micron-scale forces at the cellular level? Specifically, the PI will determine the mechanisms of chromosome segregation and cell division in bacteria. The proposed experiments will investigate intracellular organization and force generation in bacteria through (i) imaging, (ii) mechanical perturbation and (iii) force measurement. Super-resolution, three-dimensional imaging will be used to quantify the geometric conformations of cytoskeletal proteins inside cells and how they respond to externally applied forces. The three-dimensional trajectories of actively segregated regions of DNA will be revealed using single particle tracking. In addition, the role of local cell curvature in the placement of the cell division plane and the ability of the contractile ring to generate mechanical force during cell division will be probed with atomic force microscopy. The proposed education plan provides learning opportunities for future biophysical scientists through combined (i) course development, (ii) hands-on observations and (iii) a multimedia cellular environment. The PI will develop and teach two new courses on Biological Physics that integrate research results in a broader biophysical context through his joint appointment in the Department of Physics and the Lewis-Sigler Institute for Integrative Genomics at Princeton University. To motivate the next generation of scientists, the PI will work with local middle school students as part of Princeton Universitys Science and Engineering Expo, introducing them firsthand to the physics of cellular locomotion through microscopy and modeling activities. An interactive software program, partly based on imaging data from this proposal, will be created that allows students to explore the crowded and fascinating three-dimensional world that exists inside cells.
The long term goal of the proposal is to develop novel methods for studying single molecule dynamics in living systems and to understand how different length and time scales are integrated for a living bacteria or cell to emerge. This project encompasses aspects of cell biology, molecular biophysics, physics, and computational biology. The students working on the project will be trained at the interface of several fields of science. The proposed research has all ingredients to be truly transformational. This project is jointly supported by the Physics of Living Systems Program Molecular in the Division of Physics at the Physical Sciences Directorate and by the the Division of Molecular and Cellular Biosciences in the Directorate for Biological Sciences.
