Figure 2.

AQP3, not AQP5, is delivered from the Golgi to cell–cell contacts. (A and B) Representative example of release from a 19°C block of Golgi- accumulated AQP3-PAGFP (A; see Fig. 7 A) and AQP5-PAGFP (B) in pairs of adhering cells. AQP3-PAGFP rapidly accumulates at cell–cell contacts after photoactivation in the Golgi (A), whereas AQP5-PAGFP does not (B). Arrowheads in A point to the edge of AQP3-PAGFP accumulation, arrows point to the edge of cell–cell contacts, and numbers indicate the time (in minutes) after activation. The fluorescence intensity scale is pseudocolored. Bars, 5 μm. (C and D) Quantitation over time of a small spot of AQP3-PAGFP and AQP5-PAGFP fluorescence at the cell–cell contact proximal to the Golgi (blue, fluorescence intensity at cell–cell contacts; red, fluorescence intensity at the plasma membrane as equidistant from the Golgi as the spot measured at the cell–cell contact). Data points are averages of five independent experiments, and the error bars represent the SEM. The dashed boxes (top) indicate the insets shown (bottom). Quantitation shows that AQP3-PAGFP (C) accumulates at cell–cell contact, whereas AQP5-PAGFP (D) does not. Numbers indicate the time (in minutes) after activation. (E) Quantitation of the increase in AQP3-PAGFP fluorescence at cell–cell contacts relative to fluorescence loss of AQP3-PAGFP from the Golgi after release from a 19°C block. Quantitation shows that 2 min after release, 15% of the loss of AQP3-PAGFP fluorescence from the Golgi accumulates at cell–cell contact. Data points are averages of five independent experiments, and the error bars represent the SEM. Time (in minutes) is depicted on the x axis. See Video 3, available at http://www.jcb.org/cgi/content/full/jcb.200705094/DC1.