Role of the actin cytoskeleton in tuning cellular responses to external mechanical stress.
Asparuhova, MB, Gelman, L and Chiquet, M (2009) Role of the actin cytoskeleton in tuning cellular responses to external mechanical stress. Scandinavian Journal of Medicine & Science in Sports. ISSN 1600-0838
Abstract
Mechanical forces are essential for tissue homeostasis. In adherent cells, cell-matrix adhesions connect the extracellular matrix (ECM) with the cytoskeleton and transmit forces in both directions. Integrin receptors and signaling molecules in cell-matrix adhesions transduce mechanical into chemical signals, thereby regulating many cellular processes. This review focuses on how cellular mechanotransduction is tuned by actin-generated cytoskeletal tension that balances external with internal mechanical forces. We point out that the cytoskeleton rapidly responds to external forces by RhoA-dependent actin assembly and contraction. This in turn induces remodeling of cell-matrix adhesions and changes in cell shape and orientation. As a consequence, a cell constantly modulates its response to new bouts of external mechanical stimulation. Changes in actin dynamics are monitored by MAL/MKL-1/MRTF-A, a co-activator of serum response factor. Recent evidence suggests that MAL is also involved in coupling mechanically induced changes in the actin cytoskeleton to gene expression. Compared with other, more rapid and transient signals evoked at the cell surface, this parallel mechanotransduction pathway is more sustained and provides spatial and temporal specificity to the response. We describe examples of genes that are regulated by mechanical stress in a manner depending on actin dynamics, among them the ECM protein, tenascin-C.
Item Type: | Article |
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Keywords: | mechanical signaling; mesenchymal cells; focal adhesions; extracellular matrix; actin stress fibers; Rho/ROCK signaling; megakaryoblastic leukemia protein |
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Date Deposited: | 14 Dec 2009 13:50 |
Last Modified: | 14 Dec 2009 13:50 |
URI: | https://oak.novartis.com/id/eprint/1010 |