Chatterjee D, Chakraborty M, Leit M, Neff L, Jamsa-Kellokumpu S, Fuchs R, Baron R
Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510.
Proc Natl Acad Sci U S A. 1992 Jul 15;89(14):6257-61. doi: 10.1073/pnas.89.14.6257.
Analysis of proton (H+) transport by inside-out vesicles derived from highly purified chicken osteoclast (OC) membranes has revealed the presence of a newly discovered type of vacuolar H+ ATPase (V-ATPase). Unlike vesicles derived from any other cell type or organelle, H+ transport in OC-derived vesicles is sensitive to V-ATPase inhibitors (N-ethylmaleimide and Bafilomycin A1) and vanadate (IC50, 100 microM), an inhibitor previously found to affect only P-type ATPases. The OC H+ ATPase contains several V-like subunits (115, 39, and 16 kDa) but subunits A and B of the catalytic domain of the enzyme differ from that of other V-ATPases. In OCs, subunit A has a mass of 63 kDa instead of the 67-70 kDa expressed in monocytes, macrophages, and kidney microsomes, which contain a vanadate-insensitive H+ ATPase. Moreover, two types of 57- to 60-kDa B subunits are also found: one is expressed predominantly in OCs and the other is expressed in kidney microsomes. The OC H+ pump may therefore constitute a class of H+ ATPase with a unique pharmacology and specific isoforms of two subunits in the catalytic portion of the enzyme. This H+ ATPase is involved in resorption of bone and may be expressed in a cell-specific manner, thereby opening possibilities for therapeutic intervention.
对源自高度纯化的鸡破骨细胞（OC）膜的内翻囊泡进行的质子（H+）转运分析揭示了一种新发现的液泡H+ATP酶（V-ATP酶）的存在。与源自任何其他细胞类型或细胞器的囊泡不同，源自OC的囊泡中的H+转运对V-ATP酶抑制剂（N-乙基马来酰亚胺和巴弗洛霉素A1）和钒酸盐（IC50，100 microM）敏感，钒酸盐是一种先前发现仅影响P型ATP酶的抑制剂。OC H+ATP酶包含几个V样亚基（115、39和16 kDa），但该酶催化结构域的A和B亚基与其他V-ATP酶不同。在破骨细胞中，A亚基的质量为63 kDa，而不是在单核细胞、巨噬细胞和肾微粒体中表达的67 - 70 kDa，这些细胞和细胞器含有对钒酸盐不敏感的H+ATP酶。此外，还发现了两种57至60 kDa的B亚基：一种主要在破骨细胞中表达，另一种在肾微粒体中表达。因此，OC H+泵可能构成一类具有独特药理学特性和酶催化部分两个亚基特定同工型的H+ATP酶。这种H+ATP酶参与骨吸收，可能以细胞特异性方式表达，从而为治疗干预开辟了可能性。
