Activation of the Particulate and Not the Soluble Guanylate Cyclase Leads to the Inhibition of Ca2+ Extrusion through Localized Elevation of cGMP

Olga Zolle,Alison M Lawrie,Alec W.M Simpson

doi:10.1074/jbc.m000786200

Olga Zolle, Alison M Lawrie + Show 1 more

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https://doi.org/10.1074/jbc.m000786200

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Abstract

We examined whether localized increases in cytosolic cGMP have distinct regulatory effects on the concentration of cytosolic free Ca(2+) in ECV304 cells. Stimulation of the particulate guanylate cyclase by brain-type natriuretic peptide in fura-2-loaded cells caused a profound potentiation of the ATP-stimulated and thapsigargin-stimulated rise in cytosolic free Ca(2+). This effect is mediated by the inhibition of Ca(2+) extrusion via the plasma membrane Ca(2+)-ATPase pump. Furthermore, the addition of brain-type natriuretic peptide caused the partial inhibition of cation influx in ATP-stimulated cells. In contrast, elevation of cytosolic cGMP by activation of the soluble guanylate cyclase induced by the addition of sodium nitroprusside causes an increased reuptake of Ca(2+) into the intracellular stores without affecting cation influx or Ca(2+) efflux. Thus, localized pools of cGMP play distinct regulatory roles in the regulation of Ca(2+) homeostasis within individual cells. We define a new role for natriuretic peptides in the inhibition of Ca(2+) efflux that leads to the potentiation of agonist-evoked increases in cytosolic free Ca(2+).

Highlights

We examined whether localized increases in cytosolic cGMP have distinct regulatory effects on the concentration of cytosolic free Ca2؉ in ECV304 cells
We find that NO-stimulated soluble guanylate cyclase and not the particulate guanylate cyclase is involved in the stimulation of Ca2ϩ sequestration into the intracellular Ca2ϩ stores
Effects of brain-type natriuretic peptide (BNP), sodium nitroprusside (SNP), and Bt2cGMP on [Ca2ϩ]c—Direct stimulation of the particulate guanylate cyclase was induced by bolus addition of 100 nM BNP to fura-2-loaded cells

Summary

Introduction

We examined whether localized increases in cytosolic cGMP have distinct regulatory effects on the concentration of cytosolic free Ca2؉ in ECV304 cells. Stimulation of the particulate guanylate cyclase by brain-type natriuretic peptide in fura-2-loaded cells caused a profound potentiation of the ATP-stimulated and thapsigarginstimulated rise in cytosolic free Ca2؉. This effect is mediated by the inhibition of Ca2؉ extrusion via the plasma membrane Ca2؉-ATPase pump. These take the form of microdomains [15], Ca2ϩ waves [16], polarized responses [17], and effects limited to the plasma membrane [18, 19] This localization of the key processes involved in Ca2ϩ homeostasis supports the generation of complex spatial and temporal patterns of Ca2ϩ signaling. The separate subcellular sources of cGMP offer the possibility of localized elevation of cGMP within a cell, putatively under the plasma membrane or within the cytosol

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