Plasma membrane calcium-ATPase in cultured human retinal pigment epithelium

Brian G. Kennedy, Nancy J. Mangini

Research output: Contribution to journalArticlepeer-review

24 Scopus citations

Abstract

The present work demonstrates the presence of plasma membrane (Ca2+ + Mg2+)-ATPase (PMCA) activity in cultured human retinal pigment epithelium (HRPE). Whole-cell HRPE homogenates exhibited Ca2+-stimulated ATPase activity that was inhibited with high affinity (IC50 = 60 nM) by eosin, a potent inhibitor of the erythrocyte PMCA. This activity was not inhibited by thapsigargin, a selective inhibitor of the sarcoplasmic/endoplasmic reticulum Ca2+-ATPase (SERCA). A PMCA-specific monoclonal antibody exhibited staining in attached HRPE monolayers. By Western blot analysis of SDS-PAGE separations of whole cell lysates of HRPE, this antibody identified a single band at ~ 145 kD. Finally, a Ca2+-dependent, La3+-augmented phosphoprotein, which comigrated with anti-PMCA immunoreactivity, was also detected. Taken together, these results show that cultured HRPE express PMCA activity.

Original languageEnglish (US)
Pages (from-to)547-556
Number of pages10
JournalExperimental eye research
Volume63
Issue number5
DOIs
StatePublished - Nov 1996

Keywords

  • HRPE
  • PMCA
  • calcium
  • calcium pump
  • calcium-magnesium-adenosine triphosphatase
  • eosin
  • phosphorylation
  • transport

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

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