Regulation of store-operated Ca2+ entry in pulmonary artery smooth muscle cells
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Updated: Jun 21, 2026

Fluorescence-based Measurement of Store-operated Calcium Entry in Live Cells: from Cultured Cancer Cell to Skeletal Muscle Fiber
Published on: February 13, 2012
Stuart P McElroy1, Robert M Drummond, Alison M Gurney
1Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 27 Taylor Street, Glasgow G4 0NR, United Kingdom.
Abstract:
Store-operated Ca2+ entry (SOCE) is an important mechanism for Ca2+ influx in smooth muscle cells; however the activation and regulation of this influx pathway are incompletely understood. In the present study we have examined the effect of several protein kinases in regulating SOCE in pulmonary artery smooth muscle cells (PASMCs) of the rat. Inhibition of protein kinase C with chelerythrine (3microM) potentiated SOCE by 47+/-2%, while the tyrosine kinase inhibitors genistein (100microM) and tyrphostin 23 (100microM) caused a significant reduction in SOCE of 55+/-9% and 43+/-7%, respectively. It has been proposed that Ca2+-insensitive phospholipase A(2) (iPLA(2)) is involved in the activation of SOCE in many different cell types. The iPLA(2) inhibitor, bromoenol lactone had no effect on SOCE, suggesting that this mechanism was not involved in the activation of the pathway. The calmodulin antagonists, calmidazolium (CMZ) (10microM) and W-7 (10microM) appeared to potentiate SOCE in PASMCs. Further investigation established that CMZ was actually activating a Ca2+ influx pathway that was independent of the filling state of the sarcoplasmic reticulum. The CMZ-activated Ca2+ influx was blocked by Gd3+ (10microM), but unaffected by 2-APB (75microM), indicating a pharmacological profile distinct from the classical SOCE pathway.
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