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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Acid Phosphatase / genetics
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Acid Phosphatase / metabolism
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Animals
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Antibodies / pharmacology
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Cell Differentiation* / genetics
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Eye Proteins / genetics
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Eye Proteins / metabolism*
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Gene Expression
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Immunoprecipitation
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Integrin beta1 / metabolism
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Integrin beta3 / metabolism
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Isoenzymes / genetics
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Isoenzymes / metabolism
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Membrane Glycoproteins / genetics
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Membrane Glycoproteins / metabolism*
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Mice
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NF-kappa B / metabolism
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Osteoclasts / cytology*
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Osteoclasts / metabolism
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RANK Ligand / genetics
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RANK Ligand / metabolism
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Tartrate-Resistant Acid Phosphatase
Substances
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Antibodies
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Eye Proteins
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Gpnmb protein, mouse
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Integrin beta1
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Integrin beta3
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Isoenzymes
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Membrane Glycoproteins
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NF-kappa B
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RANK Ligand
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Tnfsf11 protein, mouse
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Acid Phosphatase
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Tartrate-Resistant Acid Phosphatase