Evidence for an immunological and functional relationship between superoxide dismutase and a high molecular weight osteoclast plasma membrane glycoprotein

Merry Jo Oursler, Patricia Collin‐Osdoby, Ling Li, Earlene Schmitt, Philip Osdoby

Research output: Contribution to journalArticle

15 Scopus citations

Abstract

Large multinucleated osteoclasts are the major cells responsible for bone breakdown and have been reported to produce high levels of superoxides which may contribute to the process of bone resorption (Key et al.: J Bone and Mineral Res 4 [suppl. 1]:S206, 1989). Osteoclasts also possess high levels of superoxide dismutase, a protective enzyme capable of converting toxic superoxides to less toxic H2O2 (Fridovich: J Biol Chem 264:7761–7764, 1989). The amino acid sequence of manganese and/or iron superoxide dismutase has a conserved region which exhibits substantial homology with a fragment obtained from a high molecular weight osteoclast surface marker glycoprotein which is reactive with monoclonal antibody 121F. In this report, evidence is presented substantiating immunological, biochemical, and functional similarities between the osteoclast membrane antigen recognized by the 121F monoclonal antibody and superoxide dismutase. Western blot and immunoprecipitation studies show that a monospecific polyclonal antibody generated against immunoaffinity purified antigen is cross‐reactive with superoxide dismutase. Both the antigen and a high molecular weight superoxide dismutase activity have been detected in osteoclast plasma membrane preparations. The levels of superoxide dismutase activity and the membrane antigen have been found to correlate in antigen depletion studies and in western blots probing osteoclasts and closely related marrow‐derived giant cells. Moreover, regions of osteoclast superoxide dismutase activity identified by electrophoretic zymogram analysis have been shown by gel electrophoresis and western blots to contain the high molecular weight antigen, or complexes of the antigen with the 121F monoclonal antibody when these were premixed prior to nondenaturing electrophoresis. It is proposed that the osteoclast plasma membrane possesses a high molecular weight superoxide dismutase activity. Furthermore, it appears that this activity is associated with the osteoclast antigen recognized by the 121F monoclonal antibody.

Original languageEnglish (US)
Pages (from-to)331-344
Number of pages14
JournalJournal of cellular biochemistry
Volume46
Issue number4
DOIs
StatePublished - Aug 1991

Keywords

  • bone resorption
  • osteoclast
  • superoxide dismutase

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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