FIG. 7.

Force measurements in live cells and animals. (A) Diagram of actinin-stFRET, filamin-stFRET, spectrin-stFRET, and collagen-stFRET; (B) collagen-stFRET and collagen-GFP distribution pattern in C. elegans cuticles. Only construct 3 (as shown in A) was indistinguishable from Collagen-GFP; (C) 3T3 Cells expressing actinin, filamin, and spectrin stFRET constructs. The images of Venus display the probe distribution, the FRET ratio 16 color map shows constitutive stress in these proteins and uneven force distribution in subcellular domains, and higher FRET ratio reflects higher constitutional stress. To see this illustration in color, the reader is referred to the web version of this article at www.liebertpub.com/ars