FIGURE 7.

Mutating the arginine and glutamine fingers of EPI64B important for Rab GAP activity reduces the ability of EPI64B. A, isolated mouse pancreatic acini were co-infected with 3 × 10⁶ pfu/ml Xpress-tagged Rab27B WT and 2 × 10⁷ pfu/ml EPI64B WT, EPI64B R134K, EPI64B Q171L, or GFP adenovirus, respectively, and then incubated for 16 h. GTP-Rab27B levels were examined by pulldown assay from pancreatic acinar cell lysates with the GST-SHD followed by Western blotting with anti-Xpress antibody. Bars indicate means ± S.E. (error bars) from three independent experiments. ***, p < 0.001 for mutants compared with EPI64B WT. B, isolated ICR mouse pancreatic acini were incubated 2 × 10⁷ pfu/ml EPI64B WT, EPI64B R134K, EPI64B Q171L, or GFP adenovirus, respectively, for 16 h. Acini were then resuspended and incubated with various concentrations of CCK for 30 min, and amylase release was determined by amylase assay. Results are mean ± S.E. (error bars) from three independent experiments. *, p < 0.05 (EPI64B WT versus GFP).