RT info:eu-repo/semantics/article
T1 Ca2+ homeostasis in the endoplasmic reticulum measured with a new low-Ca2+-affinity targeted aequorin
A1 Fuente Pérez, Sergio de la
A1 Fonteriz García, Rosalba Inés
A1 Montero Zoccola, María Teresa
A1 Álvarez Martín, Javier
K1 Calcio en el organismo
AB We use here a new very low-Ca2+-affinity targeted aequorin to measure the [Ca2+] in the endoplasmicreticulum ([Ca2+]ER). The new aequorin chimera has the right Ca2+-affinity to make long-lasting measurementsof [Ca2+]ER in the millimolar range. Moreover, previous Ca2+-depletion of the ER is no longerrequired. The steady-state [Ca2+]ER obtained is 1–2 mM, higher than previously reported. In addition,we find evidence that there is significant heterogeneity in [Ca2+]ER among different regions of the ER.About half of the ER had a [Ca2+]ER of 1 mM or below, and the rest had [Ca2+]ER values above 1 mM andin some parts even above 2 mM. About 5% of the ER was also found to have high [Ca2+]ER levels but to bethapsigargin-insensitive and inositol trisphosphate insensitive. The rate of refilling with Ca2+ of the ERwas almost linearly dependent on the extracellular [Ca2+] between 0.1 and 3 mM, and was only partiallyaffected by mitochondrial membrane depolarization. Instead, it was significantly reduced by loading cellswith chelators, and the fast chelator BAPTA was much more effective than the slow chelator EGTA. Thissuggests that local [Ca2+] microdomains connecting the store operated Ca2+ channels with the ER Ca2+pumps may be important during refilling.
PB Elsevier Ltd.
SN 0143-4160
YR 2013
FD 2013
LK http://uvadoc.uva.es/handle/10324/5994
UL http://uvadoc.uva.es/handle/10324/5994
LA eng
NO Cell Calcium, 2013, vol. 54, p. 37-45
NO Producción Científica
DS UVaDOC
RD 22-nov-2024