Plasma membrane calcium pump activity is affected by the membrane protein concentration: Evidence for the involvement of the actin cytoskeleton

Laura Vanagas, Rolando C. Rossi, Ariel J. Caride, Adelaida G. Filoteo, Emanuel E. Strehler, Juan Pablo F.C. Rossi

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

Plasma membrane calcium pumps (PMCAs) are integral membrane proteins that actively expel Ca2+ from the cell. Specific Ca2+-ATPase activity of erythrocyte membranes increased steeply up to 1.5-5 times when the membrane protein concentration decreased from 50 μg/ml to 1 μg/ml. The activation by dilution was also observed for ATP-dependent Ca2+ uptake into vesicles from Sf9 cells over-expressing the PMCA 4b isoform, confirming that it is a property of the PMCA. Dilution of the protein did not modify the activation by ATP, Ca2+ or Ca2+-calmodulin. Treatment with non-ionic detergents did not abolish the dilution effect, suggesting that it was not due to resealing of the membrane vesicles. Pre-incubation of erythrocyte membranes with Cytochalasin D under conditions that promote actin polymerization abolished the dilution effect. Highly-purified, micellar PMCA showed no dilution effect and was not affected by Cytochalasin D. Taken together, these results suggest that the concentration-dependent behavior of the PMCA activity was due to interactions with cytoskeletal proteins. The dilution effect was also observed with different PMCA isoforms, indicating that this is a general phenomenon for all PMCAs.

Original languageEnglish (US)
Pages (from-to)1641-1649
Number of pages9
JournalBiochimica et Biophysica Acta - Biomembranes
Volume1768
Issue number6
DOIs
StatePublished - Jun 2007

Keywords

  • Calcium
  • Calmodulin
  • Cytochalasin D
  • Cytoskeleton
  • Membrane
  • PMCA

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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