Study on acidic environment formation by V-ATPase using single molecule observation

我们发现破骨细胞特异性的V-ATPase(液泡型质子泵ATPase)由A3和D2亚型组成。具有A3异构体的V-ATPase定位于溶酶体膜上，是溶酶体向质膜转运所必需的。溶酶体酶的分泌和破骨细胞外的酸化是骨吸收的重要因素。另一方面，我们已经建立了实验系统来观察单分子V-ATPase的亚基旋转，并检测催化结构域和质子途径的组装。这些体系对于阐明造成各种酸性环境的分子机制是必不可少的。

We have found that osteoclast-specific V-ATPase(vacuole-type proton-pumping ATPase) is composed of a3 and d2 isoforms. V-ATPase with a3 isoform is localized on lysosomal membrane, and is essential for traffic of lysosomes to plasmamembrane. Secretion of lysosomal enzymes and acidification outside osteoclasts are important for bone resorption. On the other hand, we have established experimental systems to observe subunit rotation of single molecule V-ATPase and to examine assembly of the catalytic domain and the proton pathway. These systems are essential to elucidate molecular mechanism that creates various acidic environments.