All Publications


  • Optical control of fast and processive engineered myosins in vitro and in living cells. Nature chemical biology Ruijgrok, P. V., Ghosh, R. P., Zemsky, S. n., Nakamura, M. n., Gong, R. n., Ning, L. n., Chen, R. n., Vachharajani, V. T., Chu, A. E., Anand, N. n., Eguchi, R. R., Huang, P. S., Lin, M. Z., Alushin, G. M., Liphardt, J. T., Bryant, Z. n. 2021

    Abstract

    Precision tools for spatiotemporal control of cytoskeletal motor function are needed to dissect fundamental biological processes ranging from intracellular transport to cell migration and division. Direct optical control of motor speed and direction is one promising approach, but it remains a challenge to engineer controllable motors with desirable properties such as the speed and processivity required for transport applications in living cells. Here, we develop engineered myosin motors that combine large optical modulation depths with high velocities, and create processive myosin motors with optically controllable directionality. We characterize the performance of the motors using in vitro motility assays, single-molecule tracking and live-cell imaging. Bidirectional processive motors move efficiently toward the tips of cellular protrusions in the presence of blue light, and can transport molecular cargo in cells. Robust gearshifting myosins will further enable programmable transport in contexts ranging from in vitro active matter reconstitutions to microfabricated systems that harness molecular propulsion.

    View details for DOI 10.1038/s41589-021-00740-7

    View details for PubMedID 33603247

  • Spatiotemporal control of liquid crystal structure and dynamics through activity patterning. Nature materials Zhang, R. n., Redford, S. A., Ruijgrok, P. V., Kumar, N. n., Mozaffari, A. n., Zemsky, S. n., Dinner, A. R., Vitelli, V. n., Bryant, Z. n., Gardel, M. L., de Pablo, J. J. 2021

    Abstract

    Active materials are capable of converting free energy into mechanical work to produce autonomous motion, and exhibit striking collective dynamics that biology relies on for essential functions. Controlling those dynamics and transport in synthetic systems has been particularly challenging. Here, we introduce the concept of spatially structured activity as a means of controlling and manipulating transport in active nematic liquid crystals consisting of actin filaments and light-sensitive myosin motors. Simulations and experiments are used to demonstrate that topological defects can be generated at will and then constrained to move along specified trajectories by inducing local stresses in an otherwise passive material. These results provide a foundation for the design of autonomous and reconfigurable microfluidic systems where transport is controlled by modulating activity with light.

    View details for DOI 10.1038/s41563-020-00901-4

    View details for PubMedID 33603187

  • Optical Control of Fast and Processive Engineered Myosins In Vitro and in Living Cells Ruijgrok, P. V., Ghosh, R. P., Nakamura, M., Zemsky, S., Chen, R., Vachharajani, V., Liphardt, J. T., Bryant, Z. CELL PRESS. 2019: 259A