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Real‐time observation of cytoskeletal stresses and subsequent focal adhesion remodeling in live cells
Author(s) -
Hua Susan,
Ye Nannan,
Verma Deepika,
Meng Fanjie,
Sachs Frederick
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.1063.10
Subject(s) - focal adhesion , cytoskeleton , paxillin , stress fiber , actin , adhesion , microbiology and biotechnology , cell adhesion , actin cytoskeleton , chemistry , biophysics , cell , biology , signal transduction , biochemistry , organic chemistry
Cytoskeletal stresses are important regulators of cell adhesion, migration and growth. While cytoskeleton tension has been shown to promote the development of adhesions, the force transduction mechanism remains unclear, because it requires a measurement of cytoskeletal stresses in live cells. We have developed a group of stress sensitive FRET probes that can be inserted into cross‐linking proteins of the cytoskeleton to measure the stresses in live cells. By co‐expressing FRET probes in actinin and fluorescence labeled paxillin, we simultaneously observed the time‐dependent changes in cytoskeletal stresses and the dynamics of its linking focal adhesions. We show that an increase in cytoskeletal stress at the focal adhesions results in an elongation of the adhesions in the direction of force, and a decrease of local force causes disassembly of the adhesions. The orientation of the adhesion sites maintains parallel with the stress fibers at the cell‐cell contacts. At the open edge, a highly active protrusion is followed by the formation of periphery actin bundles and the rotation of associated adhesions. Interestingly, the change of orientation of adhesions appears to be directed by the force in the stress fibers, involving a separation of actin fibers from adhesion sites and a stress directed lateral displacement of adhesions. These results provide the direct observation of the force transduction at focal adhesions.