engleski

Traction, trypsin, and tensegrity

Motivation. Cells exert traction on their substrates. These mechanical stresses are crucial in cell contraction, locomotion, growth, and differentiation. Method. The cells are plated on a flexible gel substrate with embedded fluorescent microbeads. The traction of the cells induces a deformation of the gel and hence displacement of the microbeads. These displacements are used to compute the traction by Fourier Transform Traction Cytometry (FTTC). Results. The FTTC method was tested using computer simulations. The method was applied to cultured human airway smooth muscle cells before and after their partial detachment from the substrate, induced by trypsin. Before detachment, the traction was highest at the cell ends, whereas there was no traction after partial detachment. Conclusions. Adherent cells are tensed and attached to the substrate mainly at their ends. After one end of the cell detaches, the cell rebounds like a spring to its intact attachment site. The cells typically retract towards the site of highest traction, possibly because this is the site of strong attachments. Retraction of the cell after partial detachment is consistent with the tensegrity model of cell mechanics, in which tension in the cytoskeleton is crucial for the mechanical stability of cells.

Traction microscopy; mechanical stress; cytoskeleton; cell contraction; adhesion; retraction

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