Protein kinases modulate store-operated channels in pulmonary artery smooth muscle cells

Abstract

Background. This study investigates whether protein kinase G (PKG), protein kinase A (PKA) and protein kinase C (PKC) are involved in the regulatory mechanisms of store-operated channel (SOC) in pulmonary arteries. Methods. Pulmonary artery smooth muscle cells (PASMCs) were enzymatically dissociated from rat intralobar pulmonary arteries. Whole cell, cell-attached and inside-out patch-clamp electrophysiology were used to monitor SOCs in isolated PASMCs. Results. Initially the Ca2+-ATPase inhibitor cyclopiazonic acid (CPA, 10 M) initiated a whole cell current that was reduced by the SOC blocker SKF-96365 (10 M). Subsequent work using both cell-attached and whole cell configurations revealed that the PKG and PKA inhibitors, KT5823 (3 M) and H-89 (10 M), also stimulated SOC activity; this augmentation was attenuated by the SOC blockers SKF-96365 (10 M) and Ni2+ (0.1 mM). Finally using the inside-out configuration, the PKC activator phorbol 12-myristate 13-acetate (PMA, 10 M) was confirmed to modestly stimulate SOC activity although this augmentation appeared to be more substantial following the application of 10 M inositol 1,4,5-triphosphate (Ins(1,4,5)P3). Conclusions. SOC activity in PASMCs was stimulated by the inhibition of PKG and PKA and the activation of PKC. Our findings suggest that the SOC could be a substrate of these protein kinases, which therefore would regulate the intracellular concentration of calcium and pulmonary arteriopathy via SOC. © 2011 Chen et al; licensee BioMed Central Ltd.