Fig. 2.

Glucose gradients in C2C12 cells. Average FRET ratios obtained for specific regions in a C2C12 cell exhibiting gradients of ratio intensity similar to Fig. 1. In a, traces 1 and 3 were obtained by defining two regions of interest, near the nucleus and at the cell periphery, respectively. Trace 2 was acquired by integrating the entire cell surface. Note that the CFP and YFP intensities were greater. In b, superposition of traces 1 and 3 indicates that the change in FRET ratio had similar time course in both cases, although the absolute level was higher at the cell center, suggesting lower level of intracellular glucose. The table summarizes these data