Inactive Rac1 reverses the inhibitory effect of RhoGDI1 on RhoA activation.

<p>DN-Rac1, WT-RhoGDI1 or combination of both were expressed in pancreatic acini using adenoviral delivery. Overnight pancreatic acini were stimulated with CCK (300 pM) for 5 min and then RhoA activation was determined by pull-down assay. <i>Top:</i> A representative immunoblot for RhoA shows that the expression of DN-Rac1 increases the amount of GTP-RhoA in both non-stimulated and stimulated conditions. The expression of WT-RhoGDI1 inhibits RhoA activation by sequestering inactive RhoA. The co-expression of DN-Rac1 and WT-RhoGDI1 prevents the inhibitory effect of RhoGDI1 on RhoA activation. Comparable expression of DN-Rac1 and WT-RhoGDI1 was analyzed using anti-HA-tag and anti-RhoGDI1 antibodies, respectively. <i>Bottom:</i> A quantitative analysis of RhoA activation. Values are means ± SE (n = 4 experiments). *: p<0.05 vs control, †: p<0.05 vs RhoGDI1 and ‡: p<0.05 vs CCK.