Table 1.

IQGAP2^*Cdc42 interaction is essential for the apical membrane extension

Treatment	Apical Vacuole Diameter (μm)a
Cimetidine	3.9  ± 0.7
Histamine + IBMX	15.9  ± 1.5
Control peptide + histamine + IBMX	15.7  ± 1.7
IQGAP peptide + histamine + IBMX	7.9  ± 1.1*

^* p < 0.01 compared with those of stimulated cells that were pretreated with the control peptide. 

^a Diameter of apical vacuoles was measured as an index for apical membrane extension associated with acid secretion. Data were obtained from >100 cells in which apical vacuoles were in the same focal plane (see MATERIALS AND METHODS).