Figure 5.

Interaction between Cdc42 and IQGAP2 is essential for parietal cell activation. (A) Synthetic peptides, both inhibitory and scrambled (control), were added into SLO-gland suspensions as indicated amount (micrograms per milliliter). Glands were then stimulated with 100 μM cAMP plus 100 μM ATP, and the AP uptake was measured as described in MATERIALS AND METHODS. AP data are plotted as percentage of the stimulated control for each of experiment. Error bars represent SE; n = 4. *, significant difference compared with stimulated controls (p < 0.05). (B) Constitutive active GST-cdc42 proteins coupled to glutathione agarose beads were used to absorb IQGAP proteins followed by incubation of aliquots beads with the inhibitory and scrambled peptide, respectively. Agarose bead-bound proteins were fractionated by SDS-PAGE and stained with Coomassie Blue. Note there are two IQGAP polypeptides were wiped off by 10 μg/ml inhibitory peptide.