title: Osteoactivin is a novel osteoclastic protein and plays a key role in osteoclast differentiation and activity.
abstract: This study presents gene expression, protein expression, and in situ immunohistochemical evidence that osteoclasts express high levels of osteoactivin (OA), which had previously been reported to be an osteoblast-specific protein in bone. OA expression in osteoclasts was up-regulated upon receptor activator of NFkappaB ligand-induced differentiation. Suppression of functional activity of OA with neutralizing antibody reduced cell size, number of nuclei, fusion, and bone resorption activity of osteoclasts. OA was co-immunoprecipitated with integrin beta3 and beta1, indicating that OA co-localizes with integrin beta3 and/or beta1 in a hetero-polymeric complex in osteoclasts. These findings indicate that OA is a novel osteoclastic protein and plays a role in osteoclast differentiation and/or activity.
authors.affiliation: Musculoskeletal Disease Center (151), Jerry L. Pettis Memorial VA Medical Center, Loma Linda, CA 92357, USA. Matilda.Sheng@va.gov
authors.forename: Matilda H-C
authors.initials: MH
authors.lastname: Sheng
authors.forename: Jon E
authors.initials: JE
authors.lastname: Wergedal
authors.forename: Subburaman
authors.initials: S
authors.lastname: Mohan
authors.forename: K-H William
authors.initials: KH
authors.lastname: Lau
mesh_terms: D000135:Acid Phosphatase / Q000235:genetics / Q000378:metabolism; D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D002454:Cell Differentiation / Q000235:genetics; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D047468:Immunoprecipitation; D019012:Integrin beta1 / Q000378:metabolism; D039661:Integrin beta3 / Q000378:metabolism; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism; D010010:Osteoclasts / Q000166:cytology* / Q000378:metabolism; D053245:RANK Ligand / Q000235:genetics / Q000378:metabolism; D000071681:Tartrate-Resistant Acid Phosphatase
chemical_list: D000906:Antibodies; D005136:Eye Proteins; C445671:Gpnmb protein, mouse; D019012:Integrin beta1; D039661:Integrin beta3; D007527:Isoenzymes; D008562:Membrane Glycoproteins; D016328:NF-kappa B; D053245:RANK Ligand; C505689:Tnfsf11 protein, mouse; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase