Cells exert and respond to mechanical forces, but investigating how these signals are transduced is a challenge. By measuring differential labeling of cysteines in stressed and relaxed cells, Johnson et al. identify proteins that change their structure in response to stress. Using mass spectroscopy, they determined the specific Cys residues that experience structural changes. In red blood cells, spectrin unfolds as cells are stressed, and in mesenchymal stem cells, both myosin IIA and vimentin show differential labeling in tensed versus drug-relaxed cells.
C. P. Johnson, H.-Y. Tang, C. Carag, D. W. Speicher, D. E. Discher, Forced unfolding of proteins within cells. Science 317, 663-666 (2007). [Abstract] [Full Text]
