2022, Vol. 26 ›› Issue (25): 4004-4009

Roles of F-actin and myosin II in the regulation of cell mechanics

Fan Jiayu, Xu Limeng, Liu Yang, Wang Li   

Abstract: BACKGROUND: At present, the roles of actin and myosin II, two important cytoskeletal proteins, have been widely studied, but their roles in the regulation of cell mechanics are still incomplete.  
OBJECTIVE: To elucidate the roles of actin and myosin in the regulation of cell mechanical properties.
METHODS: The surface elastic modulus of the long axis and short axis terminal regions of the HeLa cells over time was measured by atomic force microscopy. The Cytochalasin D (inhibitor of actin polymerization), blebbsitatin (inhibitor of ATPase of myosin II) and Calysulin A (enhancer of the myosin II contractive activity) were used to treat HeLa cells. The F-actin, myosin II and activation characteristics of Rho A in HeLa cells were analyzed by confocal microscope.  
RESULTS AND CONCLUSION: (1) In the inhibitor treatment group, the surface elastic modulus at the long axis and short axis terminal regions showed a trend changes, and the change of opposite terminal regions modulus was inconsistent. (2) Inhibition of F-actin polymerization decreased the surface elastic modulus, but the enhancement of myosin II contraction activity significantly increased the surface elastic modulus. (3) The surface elastic modulus increased with F-actin aggregation, and regulated by Rho A activation, but it did not change with the aggregation of myosin. (4) The results showed that the changes of mechanical properties of cells caused by actin and myosin II were not only numerical changes, but also asymmetric changes of mechanical properties. These changes were regulated by the distribution of actin fibers and the contractile activity of myosin II.
Key words: cell surface, elastic modulus, cell long axis, F-actin, myosin II, Rho A, cell mechanics, atomic force microscope