Center for Molecular Spectroscopy and Dynamics

■   SPEAKER

Prof. Hyokeun Park (The Hong Kong University of Science and Technology)

■   TITLE

Real-time imaging of single myosin X molecules

■   ABSTRACT

Myosin X plays an important role in migration and metastasis of cancer. In particular, myosin X plays a critical role in formation of filopodia and invadopodia in cancer. Recent studies revealed that myosin X undergoes dimerization via an antiparallel coiled-coil domain and moves along actin bundle. Moreover, myosin X was found to contain a flexible lever arm extension. However, the stepping mechanism of this myosin X with unparallel coiled-coil and flexible lever arm extension remains elusive. Our real-time imaging of single-molecule full-length myosin X showed a broad distribution of step size, which is in contrast to well-known step sizes of myosin V that has a narrow distribution of step size. Furthermore, myosin X showed a longer run length, along actin bundles in comparison to those moving on actin filaments. We further elucidated which functional domains of myosin X play the crucial role for the stepping mechanism by constructing the chimera myosins by replacing the motor domain or lever arm of myosin X with those of myosin V. We found that the anti-parallel coiled-coil allows the multiple step sizes of myosin X along actin bundles, suggesting that the antiparallel coiled-coil is critical for positioning of the lever arm near the actin to allow rapid binding of a free head to the actin when coupled to a flexible lever arm. We also tracked single myosin X molecules in living cells and found their unique motion. The observed unique stepping mechanisms and motions are closely related to the functions of myosin X in living cells.

■    DATE AND VENUE

June 5, 2023 (Monday, 5:00 p.m. - 6:00 p.m.) Seminar Room A 116

■   LANGUAGE

Korean

■   INVITED BY

           Associate Director Wonshik Choi