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Updated: Mar 2, 2026
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Cytosolic Calcium Measurements in Renal Epithelial Cells by Flow Cytometry
Published on: October 28, 2014
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Cortical cytoskeleton dynamics regulates plasma membrane calcium ATPase isoform-2 (PMCA2) activity
Marianela G Dalghi1, Mariela Ferreira-Gomes2, Nicolás Montalbetti3
1IQUIFIB - Instituto de Química y Fisicoquímica Biológicas, Conicet/UBA, Junín 956, 1113 Buenos Aires, Argentina; Institute of Biochemistry and Molecular Medicine, Swiss National Centre of Competence in Research, NCCR TransCure, University of Bern, Bühlstrasse 28, 3012 Bern, Switzerland.
Summary
The actin cytoskeleton regulates the activity of the plasma membrane calcium ATPase (PMCA) in living cells. Disrupting actin increases PMCA activity, while stabilizing it inhibits the pump, affecting cellular calcium levels.
Area of Science:
- Cell Biology
- Biochemistry
- Physiology
Background:
- Previous studies showed purified actin modulates human plasma membrane Ca2+ ATPase 4b (hPMCA4b) activity.
- These interactions were observed in vitro, necessitating in vivo validation.
Purpose of the Study:
- To investigate the physiological relevance of PMCA and cortical cytoskeleton interactions in live cells.
- To assess the impact of actin and microtubule polymerization states on PMCA activity and membrane expression.
Main Methods:
- Transiently expressed PMCA in human embryonic kidney (HEK293) cells.
- Real-time monitoring of cytosolic calcium levels ([Ca2+]CYT).
- Pharmacological disruption/stabilization of actin and microtubule networks.
Main Results:
- Disrupting the actin cytoskeleton with cytochalasin D increased PMCA activity by ~50-100%.
- Stabilizing F-actin with jasplakinolide fully inhibited PMCA activity.
- Disrupting microtubules with colchicine decreased PMCA activity by ~40-60%.
- No changes in PMCA surface expression were observed, indicating regulation of specific activity.
Conclusions:
- PMCA activity is significantly modulated by the polymerization state of the cortical cytoskeleton in living cells.
- Cytoskeletal dynamics, not protein expression levels, are key regulators of PMCA function.
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