Epitopes of the human erythrocyte Ca2+-Mg2+ ATPase pump in human osteoblast-like cell plasma membranes

J. L. Borke, E. F. Eriksen, J. Minami, P. Keeting, K. G. Mann, J. T. Penniston, B. L. Riggs, Rajiv Kumar

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Abstract

Human osteoblast-like cells were examined for the presence of the Ca2+-Mg2+ ATPase pump. The osteoblast-like cells had characteristic features of the oesteoblast phenotype, including the presence of osteonectin, bone GLA protein, and type I collagen. The cells were able to mineralize matrix, their production of cAMP increased in response to PTH, and their alkaline phosphatase activity increased in response to 1,25-dihydroxyvitamin D3. Immunocytochemical staining of the osteoblast-like cells with a monoclonal antibody against human red cell Ca2+-Mg2+ ATPase demonstrated the presence of an epitope of the Ca2+-Mg2+ ATPase in these cells; staining of paraffin-embedded osteoblast-like cell sections demonstrated anti-Ca2+-Mg2+ ATPase staining only in cell plasma membranes. Western blot analysis of osteoblast-like cell homogenates showed that the monoclonal antibody to human erythrocyte Ca2+-Mg2+ ATPase bound to a major band at 140,000 mol wt, similar to the mol wt of known plasma membrane Ca2+-Mg2+ ATPases. The presence in the osteoblast-like cells of a Ca2+-Mg2+ ATPase similar to the human red cell calcium pump suggests that this enzyme may play a role in osteoblast intracellular calcium homeostasis.

Original languageEnglish (US)
Pages (from-to)1299-1304
Number of pages6
JournalJournal of Clinical Endocrinology and Metabolism
Volume67
Issue number6
StatePublished - 1988

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ASJC Scopus subject areas

  • Biochemistry
  • Endocrinology, Diabetes and Metabolism

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Borke, J. L., Eriksen, E. F., Minami, J., Keeting, P., Mann, K. G., Penniston, J. T., Riggs, B. L., & Kumar, R. (1988). Epitopes of the human erythrocyte Ca2+-Mg2+ ATPase pump in human osteoblast-like cell plasma membranes. Journal of Clinical Endocrinology and Metabolism, 67(6), 1299-1304.