2024-03-29T11:40:08Zhttp://uvadoc.uva.es/oai/requestoai:uvadoc.uva.es:10324/59852021-06-23T09:48:09Zcom_10324_1133com_10324_931com_10324_894col_10324_1209
Mitochondrial free [Ca2+] levels and the permeability transition
Vay, Laura
Hernández San Miguel, Esther
Domínguez Lobatón, María Carmen
Moreno Díaz-Calderón, Alfredo
Montero Zoccola, María Teresa
Álvarez Martín, Javier
Calcio - Metabolismo
Producción Científica
Mitochondrial Ca2+ activates many processes, from mitochondrial metabolism to opening of the permeability
transition pore (PTP) and apoptosis. However, there is considerable controversy regarding the
free mitochondrial [Ca2+] ([Ca2+]M) levels that can be attained during cell activation or even in mitochondrial
preparations. Studies using fluorescent dyes (rhod-2 or similar), have reported that phosphate
precipitation precludes [Ca2+]M from increasing above 2–3 M. Instead, using low-Ca2+-affinity aequorin
probes, we have measured [Ca2+]M values more than two orders of magnitude higher. We confirm here
these values by making a direct in situ calibration of mitochondrial aequorin, and we show that a prolonged
increase in [Ca2+]M to levels of 0.5–1mM was actually observed at any phosphate concentration
(0–10mM) during continuous perfusion of 3.5–100 MCa2+-buffers. In spite of this high and maintained
(>10 min) [Ca2+]M, mitochondria retained functionality and the [Ca2+]M drop induced by a protonophore
was fully reversible. In addition, this high [Ca2+]M did not induce PTP opening unless additional activators
(phenyl arsine oxide, PAO) were present. PAO induced a rapid, concentration-dependent and irreversible
drop in [Ca2+]M. In conclusion [Ca2+]M levels of 0.5–1mM can be reached and maintained for prolonged
periods (>10 min) in phosphate-containing medium, and massive opening of PTP requires additional pore
activators.
2014-09-16
2014-09-16
2009
info:eu-repo/semantics/article
Cell Calcium, 2009, vol. 45, p. 243-250
0143-4160
http://uvadoc.uva.es/handle/10324/5985
10.1016/j.ceca.2008.10.007
243
250
Cell Calcium
45
eng
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-nd/4.0/
Attribution-NonCommercial-NoDerivatives 4.0 International
Elsevier Ltd.