RT info:eu-repo/semantics/article
T1 Ca2+ Dynamics in the Secretory Vesicles of Neurosecretory PC12 and INS1 Cells
A1 Santo Domingo, Jaime
A1 Fonteriz García, Rosalba Inés
A1 Domínguez Lobatón, María Carmen
A1 Montero Zoccola, María Teresa
A1 Moreno Díaz-Calderón, Alfredo
A1 Álvarez Martín, Javier
K1 Calcio - Metabolismo
AB We have investigated the dynamics of the free[Ca2+] inside the secretory granules of neurosecretory PC12and INS1 cells using a low-Ca2+-affinity aequorin chimerafused to synaptobrevin-2. The steady-state secretory granule[Ca2+] ([Ca2+]SG] was around 20–40 lM in both cell types,about half the values previously found in chromaffin cells.Inhibition of SERCA-type Ca2+ pumps with thapsigarginlargely blocked Ca2+ uptake by the granules inCa2+-depleted permeabilized cells, and the same effect wasobtained when the perfusion medium lacked ATP. Consistently,the SERCA-type Ca2+ pump inhibitor benzohydroquinoneinduced a rapid release of Ca2+ from the granulesboth in intact and permeabilized cells, suggesting that thecontinuous activity of SERCA-type Ca2+ pumps is essentialto maintain the steady-state [Ca2+]SG. Both inositol 1,4,5-trisphosphate (InsP3) and caffeine produced a rapid Ca2+release from the granules, suggesting the presence of InsP3and ryanodine receptors in the granules. The response tohigh-K+ depolarization was different in both cell types, adecrease in [Ca2+]SG in PC12 cells and an increase in[Ca2+]SG in INS1 cells. The difference may rely on theheterogeneous response of different vesicle populations ineach cell type. Finally, increasing the glucose concentrationtriggered a decrease in [Ca2+]SG in INS1 cells. In conclusion,our data show that the secretory granules of PC12 and INS1cells take up Ca2+ through SERCA-type Ca2+ pumps andcan release it through InsP3 and ryanodine receptors, supportingthe hypothesis that secretory granule Ca2+ may bereleased during cell stimulation and contribute to secretion.
PB Springer Verlag
SN 0272-4340
YR 2010
FD 2010
LK http://uvadoc.uva.es/handle/10324/5980
UL http://uvadoc.uva.es/handle/10324/5980
LA eng
NO Cellular and Molecular Neurobiology, 2010, vol. 30, p. 1267-1274
NO Producción Científica
DS UVaDOC
RD 22-nov-2024