Overexpression of the erythrocyte plasma membrane Ca2+ pump in COS-1 cells

H. P. Adamo, A. K. Verma, M. A. Sanders, R. Heim, J. L. Salisbury, E. D. Wieben, J. T. Penniston

Research output: Contribution to journalArticlepeer-review

55 Scopus citations


A full-length cDNA corresponding to the hPMCA4 plasma membrane Ca2+ pump was assembled and expressed in COS-1 cells. The original sequence of hPMCA4 gave a very low expression. The mutation of the initiation translation site of this sequence to the consensus A/G-X-X-AUG-G increased the production of the protein. The Ca2+ pump activity in transfected cells was 1.5-3.5-fold higher than in controls. The Ca2+-dependence and the calmodulin stimulation of hPMCA4 expressed in COS-I cells were comparable with those of the erythrocyte Ca2+ pump. Immunohistochemistry experiments showed that most of the expressed protein remained in intracellular membranes. Possible explanations for this targeting of the pump are discussed.

Original languageEnglish (US)
Pages (from-to)791-797
Number of pages7
JournalBiochemical Journal
Issue number3
StatePublished - 1992

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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