Epitopes of the human erythrocyte ca2+-mg2+ atpase pump in human osteoblast-like cell plasma membranes

James L. Borke, Erik F. Eriksen, Junzaburo Minami, Philip Keeting, Kenneth G. Mann, John T. Penniston, B. Lawrence Riggs, Rajiv Kumar

Research output: Contribution to journalArticlepeer-review

46 Scopus citations


Human osteoblast-like cells were examined for the presence of the Ca2+-Mg2+ ATPase pump. The osteoblastlike cells had characteristic features of the osteoblast 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
Issue number6
StatePublished - Dec 1988

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Biochemistry
  • Endocrinology
  • Clinical Biochemistry
  • Biochemistry, medical


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