2024-03-29T01:22:19Zhttps://uvadoc.uva.es/oai/requestoai:uvadoc.uva.es:10324/59732021-06-23T09:48:22Zcom_10324_1133com_10324_931com_10324_894col_10324_1209
Calcium dynamics in catecholamine-containing secretory vesicles
Moreno Díaz-Calderón, Alfredo
Domínguez Lobatón, María Carmen
Santo Domingo, Jaime
Vay, Laura
Hernández San Miguel, Esther
Rizzuto, Rosario
Montero Zoccola, María Teresa
Álvarez Martín, Javier
Calcio en el organismo
Producción Científica
We have used an aequorin chimera targeted to the membrane of the secretory granules to monitor the free [Ca2+] inside them in neurosecretory
PC12 cells. More than 95% of the probe was located in a compartment with an homogeneous [Ca2+] around 40 M. Cell stimulation with
either ATP, caffeine or high-K+ depolarization increased cytosolic [Ca2+] and decreased secretory granule [Ca2+] ([Ca2+]SG). Inositol-(1,4,5)-
trisphosphate, cyclic ADP ribose and nicotinic acid adenine dinucleotide phosphate were all ineffective to release Ca2+ from the granules.
Changes in cytosolic [Na+] (0–140 mM) or [Ca2+] (0–10 M) did not modify either ([Ca2+]SG). Instead, [Ca2+]SG was highly sensitive to
changes in the pH gradient between the cytosol and the granules. Both carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone (FCCP) and
nigericin, as well as cytosolic acidification, reversibly decreased [Ca2+]SG, while cytosolic alcalinization reversibly increased [Ca2+]SG. These
results are consistent with the operation of a H+/Ca2+ antiporter in the vesicular membrane. This antiporter could also mediate the effects
of ATP, caffeine and high-K+ on [Ca2+]SG, because all of them induced a transient cytosolic acidification. The FCCP-induced decrease in
[Ca2+]SG was reversible in 10–15 min even in the absence of cytosolic Ca2+ or ATP, suggesting that most of the calcium content of the vesicles
is bound to a slowly exchanging Ca2+ buffer. This large store buffers [Ca2+]SG changes in the long-term but allows highly dynamic free [Ca2+]SG
changes to occur in seconds or minutes.
2014-09-16T08:47:12Z
2014-09-16T08:47:12Z
2005
info:eu-repo/semantics/article
https://doi.org/10.1016/j.ceca.2005.02.002
Cell Calcium, 2005, vol. 37, p. 555-564
0143-4160
http://uvadoc.uva.es/handle/10324/5973
555
564
Cell Calcium
37
eng
Attribution-NonCommercial-NoDerivatives 4.0 International
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-nd/4.0/
application/pdf
Elsevier Ltd.