RT info:eu-repo/semantics/article
T1 Mitochondrial free [Ca2+] levels and the permeability transition
A1 Vay, Laura
A1 Hernández San Miguel, Esther
A1 Domínguez Lobatón, María Carmen
A1 Moreno Díaz-Calderón, Alfredo
A1 Montero Zoccola, María Teresa
A1 Álvarez Martín, Javier
K1 Calcio - Metabolismo
AB Mitochondrial Ca2+ activates many processes, from mitochondrial metabolism to opening of the permeabilitytransition pore (PTP) and apoptosis. However, there is considerable controversy regarding thefree mitochondrial [Ca2+] ([Ca2+]M) levels that can be attained during cell activation or even in mitochondrialpreparations. Studies using fluorescent dyes (rhod-2 or similar), have reported that phosphateprecipitation precludes [Ca2+]M from increasing above 2–3 M. Instead, using low-Ca2+-affinity aequorinprobes, we have measured [Ca2+]M values more than two orders of magnitude higher. We confirm herethese values by making a direct in situ calibration of mitochondrial aequorin, and we show that a prolongedincrease 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 protonophorewas 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 irreversibledrop in [Ca2+]M. In conclusion [Ca2+]M levels of 0.5–1mM can be reached and maintained for prolongedperiods (>10 min) in phosphate-containing medium, and massive opening of PTP requires additional poreactivators.
PB Elsevier Ltd.
SN 0143-4160
YR 2009
FD 2009
LK http://uvadoc.uva.es/handle/10324/5985
UL http://uvadoc.uva.es/handle/10324/5985
LA eng
NO Cell Calcium, 2009, vol. 45, p. 243-250
NO Producción Científica
DS UVaDOC
RD 28-nov-2024