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. 1999 Apr 13;96(8):4426–4431. doi: 10.1073/pnas.96.8.4426

Figure 1.

Figure 1

CaM undergoes intracellular redistribution after application of CCK. The presence of CCK in the extracellular solution is indicated by the bar. (A) Relative changes in fluorescence in several regions of interest. The CCK-evoked rapid transient increase in the fluorescence signal from the SG region (red trace) is followed by a delayed, but stronger, signal from the nucleus (blue trace). These effects are accompanied by a corresponding decrease in the fluorescence intensity from the basal nonnuclear area (green trace). The traces were corrected for bleaching. Arrowheads at the top of the graph show the time points at which the five confocal images (b– f) in B were taken. (B, a) Nonconfocal-transmitted light picture of the pancreatic acinar doublet selected. DTAF-CaM was loaded into the cell on the left via a patch clamp pipette. The boxes over the nucleus (blue), SG region (red), and basal nonnuclear area (green) show where the fluorescence intensity changes were measured. (Bar = 10 μm.) (B, b– f) Color-coded images of fluorescence intensity (linear scale). (b) Before application of CCK. Note that the injected cell is stained brightly with DTAF-CaM, whereas the neighbor contains no fluorescent dye. DTAF-CaM is present throughout the cytosol, but is more concentrated in the area corresponding to the nucleus. (c– f) Series of images revealing the intracellular redistribution of DTAF-CaM evoked by CCK. (c) Before the peak response to CCK, DTAF-CaM appears to be accumulating initially in the SG region (increased intensity of yellow and red in this area as compared with b). (d) At the peak of the response the nuclear area is bright red, indicating a substantial accumulation of DTAF-CaM in this region. Note that the nonnuclear basal region is blue rather than green, indicating a low CaM concentration. (e) The fluorescence signal from the SG region is now reduced significantly (compared with d). (f) The distribution of fluorescence is similar to what was observed before stimulation (b). The overall intensity is somewhat lower than in b because of bleaching.