Academic Commons


Nonmuscle Myosin IIA-Dependent Force Inhibits Cell Spreading and Drives F-Actin Flow

Cai, Yunfei; Biais, Nicolas; Giannone, Gregory; Tanase, Monica; Jiang, Guoying; Hoffman, Jake M.; Wiggins, Chris H.; Silberzan, Pascal; Buguin, Alex; Ladoux, Benoit; Sheetz, Michael P.

Nonmuscle myosin IIA (NMM-IIA) is involved in the formation of focal adhesions and neurite retraction. However, the role of NMM-IIA in these functions remains largely unknown. Using RNA interference as a tool to decrease NMM-IIA expression, we have found that NMM-IIA is the major myosin involved in traction force generation and retrograde F-actin flow in mouse embryonic fibroblast cells. Quantitative analyses revealed that ∼60% of traction force on fibronectin-coated surfaces is contributed by NMM-IIA and ∼30% by NMM-IIB. The retrograde F-actin flow decreased dramatically in NMM-IIA-depleted cells, but seemed unaffected by NMM-IIB deletion. In addition, we found that depletion of NMM-IIA caused cells to spread at a higher rate and to a greater area on fibronectin substrates during the early spreading period, whereas deletion of NMM-IIB appeared to have no effect on spreading. The distribution of NMM-IIA was concentrated on the dorsal surface and approached the ventral surface in the periphery, whereas NMM-IIB was primarily concentrated around the nucleus and to a lesser extent at the ventral surface in cell periphery. Our results suggest that NMM-IIA is involved in generating a coherent cytoplasmic contractile force from one side of the cell to the other through the cross-linking and the contraction of dorsal actin filaments.



  • thumnail for nonmuscle-myosin-IIA-dependent-force-inhibits-cell-spreading-and-drives-f-actin-flow.pdf nonmuscle-myosin-IIA-dependent-force-inhibits-cell-spreading-and-drives-f-actin-flow.pdf application/pdf 981 KB Download File

Also Published In

Biophysical Journal

More About This Work

Academic Units
Biological Sciences
Cell Press
Published Here
September 19, 2014
Academic Commons provides global access to research and scholarship produced at Columbia University, Barnard College, Teachers College, Union Theological Seminary and Jewish Theological Seminary. Academic Commons is managed by the Columbia University Libraries.