The secretion-stimulated 80K phosphoprotein of parietal cells is ezrin, and has properties of a membrane cytoskeletal linker in the induced apical microvilli.

摘要: Stimulation of gastric acid secretion in parietal cells involves the translocation proton pump (H,K-ATPase) from cytoplasmic tubulovesicles to apical membrane form long, F-actin-containing, microvilli. Following secretion, is endocytosed back into tubulovesicles. The cell therefore offers a system for study regulated recycling, with temporally separated endocytic and exocytic steps. During cAMP-mediated stimulation, an 80 kDa peripheral protein becomes phosphorylated on serine residues. This major component, together actin pump, isolated stimulated cells, but not resting tubulovesicular membrane. Here we show that phosphoprotein closely related or identical ezrin, whose phosphorylation tyrosine residues was recently implicated induction by growth factors surface structures cultured [Bretscher, A. (1989) J. Cell Biol., 108, 921-930]. Light electron microscopy reveal ezrin associated filaments microvilli terminal web. In addition, significant amount present basolateral infoldings both cells. Extraction studies cytoskeletal unstimulated its association cytoskeleton more stable These indicate linker may play key role control assembly secretory ultimately regulation secretion. Taken earlier studies, suggest might be general substrate kinases involved actin-containing structures.