Intracellular transport of calcium from plasma membrane to mitochondria in adrenal H295R cells: implication for steroidogenesis

Article Article scientifique Article Intracellular transport of calcium from plasma membrane to mitochondria in adrenal H295R cells: implication for steroidogenesis eng 2003 author Lalevee Nathalie 529987 author Resin Véronique 507155 author Arnaudeau Serge 508253 author Demaurex Nicolas 0000-0002-9933-6772 24642 author Rossier Michel 22435 4575-4585 10.1210/en.2003-0268 12960050 0013-7227 Angiotensin II and extracellular potassium stimulate aldosterone production in adrenal glomerulosa cells by mobilizing the calcium messenger system. This response requires calcium influx across the plasma membrane, followed by calcium uptake into the mitochondria. It has been proposed that calcium is transported to the mitochondria via the lumen of the endoplasmic reticulum, acting as a kind of intracellular calcium pipeline. This hypothesis has been tested in the present study by measuring intramitochondrial calcium variations in H295R cells with a new fluorescent calcium probe, ratiometric pericam. Calyculin A, a protein phosphatase inhibitor, induced the formation of a large cortical layer of actin filaments, removing the peripheral endoplasmic reticulum away from the plasma membrane and thereby physically uncoupling the calcium channels from the pipeline. The mitochondrial calcium response to potassium was markedly reduced after calyculin treatment, but that of AngII was unaffected. Under the same conditions, potassium-stimulated pregnenolone and aldosterone production was significantly reduced, whereas the steroidogenic response to AngII remained unchanged. The inhibitory action of calyculin A on the responses to potassium was not mediated by a modification of the calcium channel activity and was not accompanied by a reduction of the cytosolic calcium response. It therefore appears that, in H295R cells, the organization of the actin cytoskeleton at the cell periphery influences the steroidogenic action of potassium, but not the response to angiotensin II. The response to potassium is proposed to be dependent on the endoplasmic reticulum-mediated transfer of calcium entering through plasma membrane calcium channels to the mitochondria. Actins/metabolism Adrenal Glands/cytology/metabolism Angiotensin II/pharmacology Biological Transport Calcium/metabolism Calcium Channels/drug effects/physiology Cell Line Cell Membrane/metabolism Cytosol/metabolism Electrophysiology Humans Intracellular Membranes/metabolism Mitochondria/drug effects/metabolism Oxazoles/pharmacology Potassium/pharmacology Potassium Chloride/pharmacology Steroids/antagonists & inhibitors/biosynthesis Tissue Distribution Dewey 612 134 Département de physiologie cellulaire et métabolisme 21C false 168 Signaux intracellulaires 210 Endocrinology 144 10 57f6e57d-de36-472f-8eda-7c77304ff6f3 Article (Published version) Public Intracellular transport of calcium from.pdf 555235 application/pdf openAccess Faculté de médecine / Section de médecine fondamentale / Département de physiologie cellulaire et métabolisme

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Intracellular transport of calcium from plasma membrane to mitochondria in adrenal H295R cells: implication for steroidogenesis	Endocrinology			2003	706	443

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