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oai:uvadoc.uva.es:10324/59702021-06-23T09:48:21Zcom_10324_1133com_10324_931com_10324_894col_10324_1209

Chromaffin-cell stimulation triggers fast millimolar mitochondrial Ca2+ transients that modulate secretion Montero Zoccola, María Teresa Alonso Alonso, María Teresa Carnicero Gila, Estela María Cuchillo Ibáñez, Inmaculada Albillos, Almudena García, Antonio G. García-Sancho Martín, Francisco Javier Álvarez Martín, Javier Calcio - Efectos fisiológicos Producción Científica Activation of calcium-ion (Ca2+) channels on the plasma membrane and on intracellular Ca2+ stores, such as the endoplasmic reticulum, generates local transient increases in the cytosolic Ca2+ concentration that induce Ca2+ uptake by neighbouring mitochondria. Here, by using mitochondrially targeted aequorin proteins with different Ca2+ affinities, we show that half of the chromaffin-cell mitochondria exhibit surprisingly rapid millimolar Ca2+ transients upon stimulation of cells with acetylcholine, caffeine or high concentrations of potassium ions. Our results show a tight functional coupling of voltage-dependent Ca2+ channels on the plasma membrane, ryanodine receptors on the endoplasmic reticulum, and mitochondria. Cell stimulation generates localized Ca2+ transients, with Ca2+ concentrations above 20–40 mM, at these functional units. Protonophores abolish mitochondrial Ca2+ uptake and increase stimulated secretion of catecholamines by three- to fivefold. These results indicate that mitochondria modulate secretion by controlling the availability of Ca2+ for exocytosis. 2014-09-16T08:08:18Z 2015-03-16T00:40:07Z 2000 info:eu-repo/semantics/article Nature Cell Biology, Febrero 2000, vol. 2, p. 57-61 1465-7392 http://uvadoc.uva.es/handle/10324/5970 57 61 Nature Cell Biology 2 eng info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by-nc-nd/4.0/ Attribution-NonCommercial-NoDerivatives 4.0 International Macmillan Magazines Ltd. SI