Figure 5
Fluorescent proteins and molecules for intracellular measurement. (a) Fluorescence resonance energy transfer (FRET) index of VinTS in migrating bovine aortic endothelial cells indicates high tension per vinculin near the protruding edges (P1 and P2) whereas force per vinculin is lower near retracting edges (R1 and R2). (b) Time traces show the inverse relationship between applied force and FRET efficiency. Fluorescence intensity time traces for donor (green) and acceptor (red). (a and b) reproduced with permission from Ref. 96. (c) FRET responses of a cell upon mechanical stimulation indicate a rapid distal Src activation and a slower wave propagation of Src activation. Reproduced with permission from Ref. 97. (d) Ratiometric fluorescence images of a cell during initial (left) and advanced (right) stages of irradiation; violet corresponds to lower viscosity and orange to higher viscosity. Reproduced with permission from Ref. 98. (e) pH measurements with ratiometric pHluorin in HeLa cells. Left panel: calibration curve of 410/470-nm excitation ratios for HeLa cells. Top right: cell surface (pH 7.40). Middle right: endosomes (pH 5.51). Bottom right: trans-Golgi network (pH 6.21). Reproduced with permission from Ref. 99.
