Mayte Montero

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Recent results indicate that Ca2+ transport by organella contributes to shaping Ca2+ signals and exocytosis in adrenal chromaffin cells. Therefore, accurate measurements of [Ca2+] inside cytoplasmic organella are essential for a comprehensive analysis of the Ca2+ redistribution that follows cell stimulation. Here we have studied changes in Ca2+ inside the(More)
BACKGROUND AND PURPOSE Ca(2+) signalling and exocytosis mediated by nicotinic receptor (nAChR) subtypes, especially the α7 nAChR, in bovine chromaffin cells are still matters of debate. EXPERIMENTAL APPROACH We have used chromaffin cell cultures loaded with Fluo-4 or transfected with aequorins directed to the cytosol or mitochondria, several nAChR(More)
Two recombinant aequorin isoforms with different Ca2+ affinities, specifically targeted to the endoplasmic reticulum (ER), were used in parallel to investigate free Ca2+ homeostasis in the lumen of this organelle. Here we show that, although identically and homogeneously distributed in the ER system, as revealed by both immunocytochemical and functional(More)
The recent availability of activators of the mitochondrial Ca(2+) uniporter allows direct testing of the influence of mitochondrial Ca(2+) uptake on the overall Ca(2+) homeostasis of the cell. We show here that activation of mitochondrial Ca(2+) uptake by 4,4',4''-(4-propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol (PPT) or kaempferol stimulates(More)
It is widely acknowledged that mitochondrial Ca2+ uptake modulates the cytosolic [Ca2+] ([Ca2+]c) acting as a transient Ca2+ buffer. In addition, mitochondrial [Ca2+] ([Ca2+]M) regulates the rate of respiration and may trigger opening of the permeability transition pore and start apoptosis. However, no mechanism for the physiological regulation of(More)
The presence and physiological role of Ca 2 1 induced Ca 2 1 release (CICR) in nonmuscle excitable cells has been investigated only indirectly through measurements of cytosolic [Ca 2 1 ] ([Ca 2 1 ] c ). Using targeted aequorin, we have directly monitored [Ca 2 1 ] changes inside the ER ([Ca 2 1 ] ER ) in bovine adrenal chromaffin cells. Ca 2 1 entry induced(More)
There is increasing evidence that mitochondria play an important role in the control of cytosolic Ca2+ signaling. We show here that the main mitochondrial Ca2+-exit pathway, the mitochondrial Na+/Ca2+ exchanger, controls the pattern of cytosolic Ca2+ oscillations in non-excitable cells. In HeLa cells, the inhibitor of the mitochondrial Na+/Ca2+ exchanger(More)
The secretory granules constitute one of the less well-known compartments in terms of Ca2+ dynamics. They contain large amounts of total Ca2+, but the free intragranular [Ca2+] ([Ca2+]SG), the mechanisms for Ca2+ uptake and release from the granules and their physiological significance regarding exocytosis are still matters of debate. We used in the present(More)
The presence and physiological role of Ca2+-induced Ca2+ release (CICR) in nonmuscle excitable cells has been investigated only indirectly through measurements of cytosolic [Ca2+] ([Ca2+]c). Using targeted aequorin, we have directly monitored [Ca2+] changes inside the ER ([Ca2+]ER) in bovine adrenal chromaffin cells. Ca2+ entry induced by cell(More)
MICU1 (Ca2+ uptake protein 1, mitochondrial) is an important regulator of the MCU (Ca2+ uniporter protein, mitochondrial) that has been shown recently to act as a gatekeeper of the MCU at low [Ca2+]c (cytosolic [Ca2+]). In the present study we have investigated in detail the dynamics of MCU activity after shRNA-knockdown of MICU1 and we have found several(More)