Figure 5.

Model suggesting how V-ATPase binding to microfilaments can sort V-ATPase into a vesicle; (A,B) Arp2/3 complex or formin (shown as orange dot) is recruited to a vesicle at a site near V-ATPases and is activated to initiate actin polymerization with actin monomer adding on near the membrane, which is characteristic of actin polymerization in cells; (C) V-ATPase binds tightly to the actin filament at a specific location. As the actin filament elongates, the V-ATPase and associated membrane are drawn away from the vesicle membrane; (D) Eventually, the membrane tether breaks or is actively broken; (E) This leaves a mother vesicle depleted in V-ATPase and a daughter vesicle enriched in V-ATPase. This model is adapted from that of Carnell and colleagues [52]. The same basic mechanism could account for the internalization of V-ATPase from the ruffled plasma membrane.