title: From lysosomes to the plasma membrane: localization of vacuolar-type H+ -ATPase with the a3 isoform during osteoclast differentiation.
abstract: Osteoclasts generate a massive acid flux to mobilize bone calcium. Local extracellular acidification is carried out by vacuolar type H+-ATPase (V-ATPase) localized in the plasma membrane. We have shown that a3, one of the four subunit a isoforms (a1, a2, a3, and a4), is a component of the plasma membrane V-ATPase (Toyomura, T., Oka, T., Yamaguchi, C., Wada, Y., and Futai, M. (2000) J. Biol. Chem. 275, 8760-8765). To establish the unique localization of V-ATPase, we have used a murine macrophage cell line, RAW 264.7, that can differentiate into multinuclear osteoclast-like cells on stimulation with RANKL (receptor activator of nuclear factor kappaB ligand). The V-ATPase with the a3 isoform was localized to late endosomes and lysosomes, whereas those with the a1 and a2 isoforms were localized to organelles other than lysosomes. After stimulation, the V-ATPase with the a3 isoform was immunochemically colocalized with lysosome marker lamp2 and was detected in acidic organelles. These organelles were also colocalized with microtubules, and the signals of lamp2 and a3 were dispersed by nocodazole, a microtubule depolymerizer. In RAW-derived osteoclasts cultured on mouse skull pieces, the a3 isoform was transported to the plasma membrane facing the bone and accumulated inside podosome rings. These findings indicate that V-ATPases with the a3 isoform localized in late endosomes/lysosomes are transported to the cell periphery during differentiation and finally assembled into the plasma membrane of mature osteoclasts.
authors.affiliation: Division of Biological Sciences, Institute of Scientific and Industrial Research, Osaka University, Osaka 567-0047, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Toyomura
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Murata
authors.forename: Akitsugu
authors.initials: A
authors.lastname: Yamamoto
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Oka
authors.forename: Ge-Hong
authors.initials: GH
authors.lastname: Sun-Wada
authors.forename: Yoh
authors.initials: Y
authors.lastname: Wada
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Futai
mesh_terms: D016475:3T3 Cells; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D002454:Cell Differentiation; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism; D007150:Immunohistochemistry; D052119:Lysosomal-Associated Membrane Protein 2; D051907:Lysosomal Membrane Proteins; D008247:Lysosomes / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D008870:Microtubules / Q000378:metabolism; D015739:Nocodazole / Q000494:pharmacology; D010010:Osteoclasts / Q000166:cytology / Q000378:metabolism*; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D050765:Qa-SNARE Proteins; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D013997:Time Factors; D025262:Vacuolar Proton-Translocating ATPases / Q000378:metabolism
chemical_list: D015703:Antigens, CD; D002352:Carrier Proteins; D052119:Lysosomal-Associated Membrane Protein 2; D051907:Lysosomal Membrane Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D020033:Protein Isoforms; D050765:Qa-SNARE Proteins; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; C505687:Tnfrsf11a protein, mouse; C505689:Tnfsf11 protein, mouse; D025262:Vacuolar Proton-Translocating ATPases; D015739:Nocodazole