Figure 7

Schematic representation of ASAP3’s roles in parietal cells. The novel roles of ASAP3 in regulating microvilli and apical membrane structures in resting parietal cells. In wild-type (WT) parietal cells (left), the Arf6 GTPase cycles between GTP-bound active form and GDP-bound inactive status. Controlled assembly of actin induces the formation of short microvilli. However in parietal cells of ASAP3-deficient mice (right), disruption of ASAP3 impairs its ArfGAP function, thus causing overactivation of Arf6 (Arf6-GTP). This enhances actin polymerization and induces the formation of elongated and tightly stacked microvilli. The representative transmission electron microscopy (TEM) images in two conditions are also shown.