FIGURE 7.

Rab32 affects ER calcium handling. A, thapsigargin-mediated calcium release with altered Rab32 activity and expression levels. HeLa cells were transfected and processed as described under “Experimental Procedures.” Calcium was released into the FURA-2-loaded cytosol by the addition of 1 μm thapsigargin. Ratiometric signals were normalized to vector-transfected cells and quantified (n = 4). *, p < 0.05; **, p < 0.01; scr, scrambled. B, representative calcium release curves for the two constructs showing significant differences. Curves are derived from 2 × 10⁶ cells, thus corresponding to an averaged response for these cells. C, thapsigargin (Thaps)-mediated calcium release with altered Rab32 activity and expression levels in the presence of Ru360. HeLa cells were transfected and processed as in A in the presence of 10 μm Ru360 (n = 4). *, p < 0.05; **, p < 0.01. D, histamine-mediated calcium release with altered Rab32 activity and expression levels. HeLa cells were transfected and processed as described under “Experimental Procedures.” Calcium was released into the FURA-2-loaded cytosol by the addition of 200 μm histamine. Ratiometric signals were normalized to vector-transfected cells and quantified (n = 3).